MIRCO-STRUCTURES OF RF SURFACES IN THE ELECTRON-BEAM-WELD REGIONS OF NIOBIUM

表面技术第52卷第12期十二烷基硫酸钠水溶液液滴在微凹槽阵列PDMS表面上的电润湿行为实验研究廖洋波1a，黄先富2,3，卢应发1a，余迎松1a,1b,1c*（1.湖北工业大学 a.土木建筑与环境学院 b.河湖健康智慧感知与生态修复教育部重点实验室c.生态环境岩土与河湖生态修复学科引智创新示范基地，武汉430068；2.中国科学院力学研究所非线性力学国家重点实验室，北京 100190；3.广东空天科技研究院（南沙），广州 511458）摘要：目的研究十二烷基硫酸钠（Sodium dodecyl sulfate, SDS）水溶液液滴在微凹槽阵列聚二甲基硅氧烷（Polydimethylsiloxane, PDMS）表面的电润湿行为特征。

方法采用注入析出法，测量含KCl的SDS水溶液液滴在微凹槽阵列非浸润表面的接触角滞后。

通过施加直流电压，研究SDS浓度和表面粗糙度对含KCl的SDS水溶液液滴的电润湿行为的影响。

结果微凹槽阵列非浸润表面表现出较强的润湿各向异性，与平行于微凹槽方向上的表观接触角（110°≤θe≤141°）、前进角（116°≤θa≤144°）和后退角（99°≤θr≤137°）相比，垂直于微凹槽方向上的表观接触角（142°≤θe≤165°）、前进角（159°≤θa≤177°）和后退角（118°≤θr≤140°）普遍更大。

当表面固定时，水溶液液滴电润湿的启动电压和饱和电压，以及发生润湿状态转变所需的电压均随着SDS浓度的增加而减小。

当水溶液中SDS的浓度固定时，沿垂直于凹槽方向的启动电压随着固相分数的减小而减小，沿平行于凹槽方向的启动电压随着固相分数的减小而增大，而饱和电压均随着固相分数的减小而减小。

结论添加十二烷基硫酸钠可以有效降低SDS水溶液液滴电润湿的启动电压和电润湿过程中水溶液液滴在微凹槽PDMS表面润湿状态转变所需的电压，使得SDS水溶液液滴在微凹槽阵列PDMS表面的电润湿行为发生了改变。

第57卷第12期 2020年12月撳纳电子技术Micronanoelectronic TechnologyVol.57 No. 12December 2020微纳结构沸腾表面构建及传热性能的研究进展曹泷1，杨辉S吴学红\周振华2(1.郑州轻工业大学能源与动力工程学院，郑州 450002;2.郑州地铁集团有限公司，郑州 450016)摘要：综述了微纳结构沸腾表面的构建方法及强化性能最新研究进展，根据表面结构形式，将其 分为纳米结构表面、微米结构表面、多孔表面和微/纳复合表面。

纳米结构表面主要采用化学方法构建，可有效增强表面气泡成核及脱离频率。

微米结构表面多采用刻蚀法和沉积法进行构建，增加了表面有效传热面积。

多孔表面一般采用烧结成型，增加了表面有效传热面积以及核化点密 度。

微/纳复合表面在沸腾过程不同尺度下强化了传热性能，可实现稳定核态沸腾，是今后沸腾 表面研究的发展方向。

关键词：沸腾表面；微纳结构；烧结；蚀刻；自组装；强化传热中图分类号：T K124 文献标识码：A文章编号：1671-4776 (2020) 12-(>982-10Research Progress of the Construction and Heat TransferCharacteristics of Boiling Surfaces with Micro-Nano StructuresCao Shuang1 ,Yang Hui1 ,Wu Xuehong1 ,Zhou Zhenhua2(1. School o f E nergy and Puzver E ngineering, Zhengzhou U niversity o f L ig h t Industry Zhengzhou450002, C hina；2. Zhengzhou M etro Group Co., Ltd., Zhengzhou450016, China)Abstract：The latest research progresses of the construction method and heat transfer enhancement characteristics of the boiling surfaces with micro-nano structures are reviewed.According to the forms of the surface structure,the boiling surfaces are classified into nano­structure surfaces,micro-structure surfaces,porous surfaces and micro-nano composite surfaces.The nano-structure surfaces are mainly constructed by chemical m ethods,which can effectively increase the surface bubbles nucleation and separation frequencies.Etching and deposition methods are often used to construct the micro-structure surfaces,which can increase the surface effective heat transfer area.The porous surfaces are usually sintered to increase the surface effective heat transfer area and nucleating point density.The micro-nano composite surfaces can enhance the heat transfer performance at different scales in the boiling process and realize stable nucleate boiling,which is a development trend of the boiling surface research in the future.Key words：boiling surface；micro-nano structure；sintering；etching；self-assembly；heat transfer enhancement收稿日期：2020-05-26基金项目：国家自然科学基金资助项目（51(川6231);河南省髙等学校重点科研项目（2()A47()(n2);郑州轻工业大学众创空间孵化项目(2019ZCK J106)E-mail ：caos@982曹泷等：微纳结构沸腾表面构建及传热性能的研究进展DOI：10. 13250/ki.wndz.2020. 12. 005 PACC：4430()引百沸腾传热作为一种伴随着气液相变的高效能量 传递方式，具有传热温差小和热流密度大等特点，由于微电子器件小型化及集成度高的发展特点，其 对高效散热方式也提出了较高的要求，相应地沸腾 传热的应用将具有巨大的优势。

英语作文从自然中获取灵感的发明全文共3篇示例，供读者参考篇1Nature's Brilliant Designs: Inventions Inspired by the Natural WorldHave you ever noticed how many amazing things there are in nature? Plants, animals, even tiny insects and microbes have special abilities that are truly incredible. As a kid, I love exploring the outdoors and observing all the wonders of the natural world. What amazes me most is how humans have been able to look at nature and get inspiration to create awesome new inventions!Let me tell you about some of the coolest examples of inventions that were inspired by observing plants and creatures in their natural environments. Get ready to have your mind blown by nature's brilliance and human ingenuity!VelcroThis one is a classic. Can you believe Velcro, which is used to stick things together so easily, was inspired by burs getting stuck to a dog's fur? It's true! In the 1940s, a Swiss engineer named George de Mestral went for a hike and noticed burrs clingingtenaciously to his clothes and his dog's fur. When he looked closely under a microscope, he saw that the burrs had hundreds of tiny hooks that caught on anything looped, like fabric.De Mestral realized he could mimic thisnatural design to create two sides – one with tiny hooks and one with soft loops –that could stick together firmly but be pulled apart easily. And so Velcro was born! Isn't it awesome that such a simple observation in nature led to something we use constantly in our shoes, jackets, bags and more?Bullet TrainsJapan's incredible high-speed bullet trains are able to go over 200 miles per hour. But there was one big problem early on – whenever the trains came out of a tunnel, they created a loud "boom" sound from the built-up air pressure. This sound was so loud it could actually cause windows near the tracks to shatter!The engineers studying this issue got an ingenious idea from...the beak of a kingfisher bird. These sleek birds can smoothly dive from the air into bodies of water to catch fish with hardly a splash. Researchers realized the unique beak shape allows air and water to flow efficiently without creating turbulence.Mimicking the kingfisher's narrow beak, the front of the bullet trains were redesigned to be more aerodynamic. This small change completely solved the boom noise problem and allowed the trains to run much more efficiently at high speeds. Just amazing that a small bird could inspire something so useful for human transportation!Termite Mound Air-ConditioningHere's one that really blows my mind. The huge mounds built by termites, which can be taller than humans, do an incredible job of air-conditioning to keep the termite colonies inside at the perfect temperature. Using a remarkably smart design aided by constant wind movement, the mounds can stay around 87°F (30°C) inside even when outside temperatures vary from 35°F (2°C) all the way to 104°F (40°C).After studying termite mounds in Zimbabwe, researchers built an office building that copied the termites' ventilation design. This "Eastgate Centre" in Harare has no conventionalair-conditioning or heating, but stays regulated at an almost perfect temperature just through carefully designed ventilation. It uses 10% of the energy needed for a normal building its size!I think it's so cool that some of the best air-conditioning comes not from human engineering, but from observing theintricate mounds of tiny termites. Nature really can out-think us if we just pay close attention.Sharkskin SwimsuitsFor the last one, I've got to share something related to one of my biggest interests – swimming! You may have heard of the specialized swimsuits designed to reduce drag and increase speed called "sharkskin swimsuits." As the name suggests, these suits were inspired by the unique texture of sharkskin.While sharkskin feels smooth if you run your hand from the tail to the head, it actually has millions of tiny teeth-like scales that face backwards. This creates a surface that allows the shark to smoothly glide through the water. The rationale behind sharkskin swimsuits is that by having a textured surface mimicking these scale-like grooves, swimmers are able to cut through the water faster.After sharkskin swimsuits were approved for competition in 2008, they helped swimmers win numerous medals and set many new world records. All thanks to carefully observing the sleek skin of nature's most skillful swimming predator!Isn't it amazing how so many human inventions have been inspired by simply observing the natural world around us? Froma casual observation like burrs on a dog leading to Velcro, to studying microscopic details like sharkskin texture, nature is an endless source of brilliant designs and solutions.As a kid, I'm constantly in awe of the incredible abilities of plants and animals all around me. And I'm grateful that humans have shown the curiosity and ingenuity to take inspiration from nature to create so many useful inventions that make our lives better. Who knows how many more awesome innovations are waiting to be discovered by paying closer attention to the marvels of the natural world? I can't wait to see what we come up with next!篇2Nature's Awesome InventionsHave you ever looked around at all the amazing things in nature and thought "Wow, that's so cool! I wish we could make something like that." Well, lots of really smart inventors and engineers have done just that! By observing plants, animals, and the natural world, they've come up with ingenious ways to solve problems and create useful new inventions. Let me tell you about some of the awesome inventions that were inspired by nature.VelcroHave you ever gone on a hike and gotten burdock burrs stuck to your socks or clothes? Those little burrs can be really annoying, but a Swiss inventor named George de Mestral had a brilliant idea after taking a close look at them. In 1941, he went home and studied the burrs under a microscope. He noticed they had lots of tiny hooks that caught on loops in the fabric. De Mestral thought he could mimic this natural design to create a unique fastener. After lots of experimentation, he finally invented what we now call Velcro! The scratchy side has thousands of tiny hooks like the burrs, and the soft side is covered in soft loops for them to grab onto. Velcro is used on so many things today like shoes, jackets, bags, and even NASA spacesuits!Bullet Train NosesJapan's famous bullet trains are some of the fastest trains in the world. But do you know what helped inspire their super aerodynamic design? It was the beak of a kingfisher bird! Engineers noticed how sleek and streamlined a kingfisher's beak is as it dives into water to catch fish. This allows the bird to move very quickly through the water with minimal resistance. The engineers used similar aerodynamic principles when designing the nose cones for the bullet trains. The cones are shaped justlike the narrow beak of a kingfisher, allowing the trains to cut through the air efficiently at incredibly high speeds.Gecko TapeGeckos are those cool little lizards that can climb up smooth walls and hang upside down from ceilings. Pretty neat, right? Well, it's all thanks to millions of tiny hairs on their toes that allow them to stick using molecular attraction. In 2012, scientists and engineers were able to recreate this incredible gripping ability to create Gecko Tape. The tape has synthetic hairs that interact with surfaces the same way a gecko's toes do through van der Waals forces. Gecko Tape can hold up to 700 pounds per square inch! It could be used to make climbing robots, help space vehicles grab onto things, or even let you walk on walls like Spider-Man. As one of the scientists said, "Nature isn't a bad model to follow."Underwater AdhesivesHave you ever tried to stick two things together under water? It's basically impossible because most glues don't work when they get wet. But certain sea creatures like mussels and barnacles figured out how to solidly attach themselves to rocks, ships, and other surfaces in the ocean. Scientists took a close look at the proteins in mussel threads to try and mimic that natural adhesiveability. They were able to reverse engineer a synthetic underwater adhesive that can be used to bond materials together in wet environments. Potential uses range from repairing boat hulls and submarines to delivering drugs or medical sensors inside the human body. Once again, nature provided the perfect model for human innovation.Self-Cleaning MaterialsHave you noticed that it's pretty hard to keep windows and other glass surfaces clean for very long? Dirt, dust, and water spots accumulate so quickly. Well, inventors took a cue from leaves and came up with incredibly self-cleaning glass! Many plant leaves have a micro-texured, super hydrophobic(water-repelling) surface that allows rain and dirt to easily wash away. By etching microscopic patterns into the surface of glass, scientists created a product that mimics that self-cleaning property of nature. When water hits the specialtexture, it forms spheres that easily pick up dust and dirt and roll right off. These self-cleaning windows can be found on many buildings today, and the technology has applications for other products too like self-cleaning exterior paint and fabric.Nature is awesome, isn't it? It has taken millions of years for plants and animals to evolve all sorts of unique abilities and traitsto survive and thrive. But instead of just marveling at them, humans have found incredibly clever ways to take inspiration from nature's designs. Who knows what other brilliantbio-inspired inventions scientists and engineers will come up with next? By observing and learning from the natural world around us, the possibilities are endless for solving problems and creating innovative new technologies. If I were you, I'd keep my eyes open for more of nature's marvels - the next great human invention might just be growing or crawling right in front of you!篇3Nature's Wonders and Human InventionsHave you ever looked around at all the amazing things in nature and thought "Wow, how did that happen?" Well, a lot of very smart people have done the same thing. By studying plants, animals, and the natural world, they've gotten ideas for incredible new inventions that make our lives better. Nature is honestly the best teacher and inspiration!One example is airplanes. You might think "How is a big metal tube anything like nature?" But the Wright brothers, who invented the first successful airplane, were inspired by observations of birds. They noticed how birds angled their wingsto steer and propelled themselves by flapping. The Wright brothers then applied similar principles of aerodynamics to build their flying machine. Wild, right?Speaking of flying, let me tell you about the awesome invention of Velcro. In 1941, a Swiss engineer named George de Mestral went on a hiking trip and got covered in burrs that stuck to his clothes and his dog's fur. Rather than just grumbling about it, de Mestral was curious. He looked at the burrs under a microscope and saw they had tiny hooks that caught on loops in the fabric. This gave him the brilliant idea to invent Velcro - two strips of fabric with hooks and loops that stick together but can be pulled apart. Thank you, burrs!There are tons of medical inventions inspired by nature too. The ancient Greeks observed willow tree bark relieving pain and fever. Much later, scientists were able to extract salicylic acid from willow bark, which led to developing aspirin and other drugs. Morphine, an important painkiller, came from the opium poppy plant. Even the idea of using leeches in medicine was taken from how they naturally attach and help drain blood.Natural creatures have been a huge inspiration for robotics. Robots have been modeled after insects, snakes, fish, and even humans to make them better at walking, swimming, climbing,and other complex movements. Scientists studied insects like cockroaches that are able to squeeze through tiny spaces and keep going even when flipped over. Using what they learned, they built robots that can do search and rescue tasks in areas too small or dangerous for humans.Sometimes nature's inspiration is right there in the name of an invention. The videocam "camcorder" got its name by combining "camera" and "recorder," just like "camouflage" comes from the French for "to disguise." Both words refer to animals' natural ability to blend into their surroundings. People copied this to develop better military disguises and eventually, portable video cameras.We can't forget about giant nautical inventions like ships and submarines, which were inspired by floating and swimming creatures like ducks, fish, and whales. Steel ship hulls got the idea of being streamlined from observing fish. And the first primitive submarines were literally just underwater rowboats sealed with animal skins. Thank you, fish and furry friends!Even some of the coolest fictional inventions were inspired by biology. Everyone's heard of Spider-Man, right? Hisweb-shooters were straight-up copied from how real spiders can shoot out sticky webs. Comic book writers were so impressed byspider silk that they gave Spider-Man the same ability, but powered by fun gadgets instead of being "naturally" produced.Some nature inspirations are just mind-blowing. You know those colorful stickers and decorations that seem to shimmer with rainbows moving across them? Their inventor was inspired by the iridescent colors found in things like butterfly wings, pearls, and soap bubbles. It happens when light bounces off tiny grooves in just the right way, creating those spectacular shimmery effects.Of course, nature doesn't directly hand us ready-made inventions - it takes super creative and hard-working people to turn those inspirations into reality. But we would be a lot worse off without the natural world to spark ideas and point us in the right direction.Even kids like you can get in on this. Maybe you'll notice how spiderwebs are structured in a certain pattern that's crazy strong for its size. Or how chameleons can change color by using fancy cells to shift the pigments in their skin. Or you'll be intrigued by the stickiness of gecko feet that allows them to climb walls. Who knows - observations like those could lead to new discoveries and groundbreaking inventions someday!At the very least, I hope this has given you a newfound appreciation for the wonders of nature and all the ways it has helped human creativity and ingenuity. Next time you're walking outside, I challenge you to keep your eyes peeled for plants, animals, or anything else that makes you think "Whoa, how does that work?" You might just be looking at the inspiration for the world's next big invention!。

层序地层学的名词英语解释GlossaryAccommodation. Another term for relative sea-level. Can be thought of as the space in which sediments can fill, defined at its base by the top of the lithosphere and at its top by the ocean surface.Basinward Shift in Facies. When viewed in cross-section, a shifting of all facies towards the center of a basin. Note that this is a lateral shift in facies, such that in vertical succession, a basinward shift in facies is characterized by a shift to shallow facies (and not a vertical shift to more basinward or deeper-water facies).Bed. Layer of sedimentary rocks or sediments bounded above and below by bedding surfaces. Bedding surfaces are produced during periods of nondeposition or abrupt changes in depositional conditions, including erosion. Bedding surfaces are synchronous when traced laterally; therefore, beds are time-stratigraphic units. See Campbell, 1967 (Sedimentology 8:7-26) for more information.Bedset. Two or more superposed beds characterized by the same composition, texture, and sedimentary structures. Thus, a bedset forms the record of deposition in an environment characterized by a certain set of depositional processes. In this way, bedsets are what define sedimentary facies. Equivalent to McKee and Weir's coset, as applied to cross-stratification. See Campbell, 1967 (Sedimentology 8:7-26) for more information.Condensation. Slow net rates of sediment accumulation. Stratigraphic condensation can occur not only through a cessation in the supply of sediment at the site of accumulation, but also in cases where the supply of sediment to a site is balanced by the rate of re moval of sediment from that site. Where net sediment accumulation rates are slow, a variety of unusual sedimentologic features may form, including burrowed horizons, accumulations of shells, authigenic minerals (such as phosphate, pyrite, siderite, glauconite, etc.), early cementation and hardgrounds, and enrichment in normally rare sedimentary components, such as volcanic ash and micrometeorites.Conformity. Bedding surface separating younger from older strata, along which there is no evidence of subaerial or submarine erosion or nondeposition and along which there is no evidence of a significant hiatus. Unconformities (sequence boundaries) and flooding surfaces (parasequence boundary) will pass laterally into correlative conformities, most commonly in deeper marine sediments.Eustatic Sea Level. Global sea level, which changes in response to changes in the volume of ocean water and the volume of ocean basins.Flooding Surface. Shortened term for a marine flooding surface.Highstand Systems Tract. Systems tract overlying a maximum flooding surface, overlain by a sequence boundary, and characterized by an aggradational to progradational parasequence set.High-Frequency Cycle. A term applied to a cycle of fourth order or higher, that is, having a period of less than 1 million years. Parasequences and sequences can each be considered high-frequency cycles when their period is less than 1 million years. Isostatic Subsidence. Vertical movements of the lithosphere as a result of increased weight on the lithosphere from sediments, water, or ice. Isostatic subsidence is a fraction of the thickness of accumulated material. For example, 100 meters of sediment will drive about 33 meters of subsidence (or less, depending on the rigidity of the lithosphere).Lowstand Systems Tract. Systems tract overlying a type 1 sequence boundary, overlain by a transgressive surface, and characterized by a progradational to aggradational parasequence set.Marine Flooding Surface. Surface separating younger from older strata, across which there is evidence of an abrupt increase in water depth. Surface may also display evidence of minor submarine erosion. Forms in response to an increase in water depth.Maximum Flooding Surface. Marine flooding surface separating the underlying transgressive systems tract from the overlying highstand systems tract. This surface also marks the deepest water facies within a sequence. This flooding surface lies at the turnaround from retrogradational to progradational parasequence stacking, although this turnaround may be gradational and characterized by aggradational stacking. In this case, a single surface defining the point of maximum flooding may not be identifiable, and a maximum flooding zone is recognized instead. The maximum flooding surface commonly, but not always, displays evidence of condensation or slow deposition, such as burrowing, hardgrounds, mineralization, and fossil accumulations. Because other flooding surfaces can have evidence of condensation (in some cases, more than the maximum flooding surface), condensation alone should not be used to define the maximum flooding surface. Meter-Scale Cycle. A term applied to a cycle with a thickness of a couple of meters or less. Parasequences and sequences can each be considered meter-scale cycles when they are thinner than a couple of meters.Parasequence. Relatively conformable (that is, containing no major unconformities), genetically related succession of beds or bedsets bounded by marine-flooding surfaces or their correlative surfaces. Parasequences are typically shallowing-upward cycles.Parasequence Boundary. A marine flooding surface.Parasequence Set. Succession of genetically related parasequences that form a distinctive stacking pattern, and typically bounded by major marine flooding surfaces and their correlative surfaces. Parasequence set boundaries may coincide with sequence boundaries in some cases. See progradational, aggradational and retrogradational parasequence sets.Peritidal. All of those depositional environments associated with tidal flats, including those ranging from the highest spring tides to somewhat below the lowest tides.Relative Sea Level. The local sum of global sea level and tectonic subsidence. Locally, a rise in eustatic sea level and an increase in subsidence rates will have the same effect on accommodation. Likewise, a fall in eustatic sea level and tectonic uplift will have the same effect on accommodation. Because of the extreme difficulty in teasing apart the effects of tectonic subsidence and eustatic sea level in regional or local studies, sequence stratigraphy now generally emphasizes relative changes in sea level, as opposed to its earlier e mphasis on eustatic sea level.Sequence. Relatively conformable (that is, containing no major unconformities), genetically related succession of strata bounded by unconformities or their correlative conformities.Sequence Boundary. Form in response to relative falls in sea level.Sequence Stratigraphy. The study of genetically related facies within a frameworkof chronostratigraphically significant surfaces.Shelf Margin Systems Tract. Systems tract overlying a type 2 sequence boundary, overlain by a transgressive surface, and characterized by a progradational to aggradational parasequence set. Without regional seismic control, most shelf margin systems tracts may be unrecognizable as such and may be inadvertently lumped with the underlying highstand systems tract as part of one uninterrupted progradational parasequence set. If this occurs, the overlying transgressive surface may be erroneously inferred to also be a type 1 sequence boundary.Systems Tract. Linkage of contemporaneous depositional systems, which are three-dimensional assemblages of lithofacies. For example, a systems tract might consist of fluvial, deltaic, and hemipelagic depositional systems. Systems tracts are defined by their position within sequences and by the stacking pattern of successive parasequences. Each sequence consists of three systems tract in a particular order. For a type 1 sequence, these are the lowstand, transgressive, and highstand systems tracts. For a type 2 sequence, these are the shelf margin, transgressive, and highstand systems tracts.Tectonic Subsidence. Vertical movements of the lithosphere, in the absence of any effects from changes in the weight of overlying sediments or water. Also called driving subsidence. Tectonic subsidence is generated primarily by cooling, stretching, loading (by thrust sheets, for example), and lateral compression of the lithosphere.Transgressive Surface. Marine flooding surface separating the underlying lowstand systems tract from the overlying transgressive systems tract. Typically, this is the first major flooding surface following the lowstand systems tract. In depositionally updip areas, the transgressive surface is commonly merged with the sequence boundary, with all of the time represented by the missing lowstand systems tract contained within the unconformity. The transgressive surface, like all of the major flooding surfaces within the transgressive systems tract, may display evidence of stratigraphic condensation or slow net deposition, such as burrowed surfaces, hardgrounds, mineralization, and fossil accumulations.Transgressive Systems Tract. Systems tract overlying a transgressive surface, overlain by a maximum flooding surface, and characterized by a retrogradational parasequence set.Type 1 Sequence Boundary. Characterized by subaerial exposure and associated erosion from downcutting streams, a basinward shift in facies, a downward shift in coastal onlap, and onlap of overlying strata. Forms when the rate of sea-level fall exceeds the rate of subsidence at the depositional shoreline break (usually at base level or at sea level). Note that this means that if such changes can be observed in outcrop and the underlying strata are marine, then the boundary is a type 1 sequence boundary.Type 2 Sequence Boundary. Characterized by subaerial exposure and a downward shift in onlap landward of the depositional shoreline break (usually at base level or at sea level). Overlying strata onlap this surface. Type 2 sequence boundaries lack subaerial erosion associated with the downcutting of streams and lack a basinward shift in facies. Forms when the rate of sea-level fall is less than the rate of subsidence at the depositional shoreline break. Note that the lack of a basinward shift in facies and the lack of a relative fall in sea level at the depositional shoreline break means that there are essentially no criteria by which to recognize a type 2 sequence boundary in outcrop.Unconformity. Surface separating younger from older strata, along which there is evidence of subaerial erosional truncation or subaerial exposure or correlative submarine erosion in some areas, indicating a significant hiatus. Forms in response to a relative fall in sea level. Note that this is a much more restrictive definition of unconformity than is commonly used or used in earlier works on sequence stratigraphy (e.g., Mitchum, 1977).Walther's Law states that "...only those facies and facies areas can be superimposed, without a break, that can be observed beside each other at the present time" (Middleton translation from German). At a Waltherian contact, one facies passes gradationally into an overlying facies, and those two facies represent sedimentary environments that were originally adjacent to one another.Water Depth. The distance between the sediment surface and the ocean surface. Water depth is reflected in sedimentary facies. A very large number of studies that purport to describe sea-level changes (both eustatic and relative) are actually only describing changes in water depth. The effects of isostatic subsidence and compaction must be removed from water depth to calculate relative sea level. This is typically done through backstripping. To calculate eustatic sea level, the rate of tectonic subsidence must then be subtracted from the relative sea-level term.。

Abstract In this work a highly scattering rear Si surface texture (RST) is realized by plasma etching of polycrystalline silicon (poly-Si) thin-film solar cells on glass. The resulting RST shows reflection haze values of more than 95% at the Si–air interface. The average feature size of the texture is around 200nm. We use a model based on the scalar scattering theory to calculate the scattering properties of the textured surface. We also use a commercial thin-film solar cell simulator to evaluate the light trapping and current enhancement induced by the texture. Combining this submicron RST with a micrometer-scale glass texture can produce a multi-scale rear Si surface texture. Assuming a 1900nm thick poly-Si solar cell on glass with a high-quality back surface reflector (silicon dioxide/silver stack), the calculated photon density absorbed in the poly-Si solar cell with the multi-scale rear Si surface texture corresponds to a 1-sun short-circuit current density ( j sc ) of 31.1mA/cm 2 , which is 1mA/cm 2 more than the calculated j sc of a poly-Si solar cell with the same thickness on textured glass but without RST. The calculated current densities do not fu lly take current loss due to parasitic absorption into consideration, hence are slightly overestimated. Highlights Plasma etching of poly-Si thin-film produces a submicron rear Si surface texture. Combining the submicron texture with a glass texture produces a multi-scale texture. The multi-scale silicon texture shows very good scattering properties. A current density of 31.1mA/cm 2 is estimated for a multi-scale textured solar cell.Abstract Polycrystalline silicon thin film solar cells on a glass substrate are investigated. The solar cell layer structure was generated by a two-step process in which first a 100-600nm thin seed layer is formed by diode laser crystallization of electron beam evaporated amorphous silicon. In a second step this layer is epitaxially thickened to 2-3.5μm by layered laser crystallization. In this process further amorphous silicon is deposited and in situ repeatedly is irradiated by excimer laser pulses. The polycrystalline layer consists of grains several hundreds of microns long and several tens of microns wide and it contains doping profile. After deposition a rapid thermal annealing and a hydrogen passivation steps follow. The back and front contacts are prepared after mesa structuring. The influence of the seed layer thickness on the solar cell performance was investigated. In addition, the absorber contamination due to the background pressure during absorber deposition and its influence on the short circuit current density was investigated. The best parameters reached for various solar cells are 540mV open circuit voltage, 20.3mA/cm 2 short circuit current density (without light trapping), 75% fill factor, and 5.2% efficiency. Highlights Layered laser crystallization leads to grain sizes of 10-300μm on glass. Open circuit voltage of 540mV and efficiency of 5.2% are achieved. Short circuitcurrent is influenced by background pressure during deposition. Short circuit current density of 20.3mA/cm 2 is reached without light trapping. Progress requires pressures below 10 -7 hPa and deposition rates over 100nm/min.Advanced light management currently plays an important role in high-performance solar cells. In this paper, a HAZO/AZO structure that was produced using RF-magnetron sputtering with segmented hydrogen mediation was proposed to further simultaneously enhance the transmittance and light trapping capability at full solar spectrum. Compared to the standard AZO front contact, the total transmittance at short wavelength and haze at full spectrum were remarkably enhanced by 5.1% and 20.7%, respectively. Additionally, the resistivity of the HAZO/AZO structure was enhanced by 16.9%. When applied as front electrodes, the spectral response of a-Si:H and μc-Si:H solar cells increased. The quantum efficiency of the a-Si:H solar cell improved by 7.9% (from 59% to 66.9%) at 400nm. An initial efficiency of 8.69% with J sc over 27mA/cm 2 was obtained for the μc-Si:H solar cell. Finally, an a-Si:H/a-SiGe:H/μc-Si:H triple-junction solar cell was obtained with the initial efficiency over 15%, which illustrates a promising and potentially cost-effective alternative structure to further improve the high-quality transparent electrodes for high-efficiency thin-film solar cells.A new plasma post-etching method, H 2 /CH 4 mixed gas plasma, is introduced to modify ZnO:B films grown by LP-MOCVD technique, successfully relaxing the double trade-offs, i.e., transparency/conductivity trade-off and surface texture/ V oc and FF trade-off. To deeply evaluate the post-etching process, optical emission spectroscopy technique is applied to diagnose the plasma condition. Upon different etching power, three distinct possible etching mechanisms are identified by analyzing the evolution of H α * , H β * , CH * emission species in the plasma space. It is demonstrated that H β * and CH * species are responsible for the physical etching process and chemical etching process, respectively, from which a new “soft” surface morphology is formed with a combination of micro- and... nano-sized texture. Additionally, H α * species can bond with ZnO and also passivate the grains boundaries, thereby making both the carrier concentration and hall mobility increase. This process is defined as chemical bonding process. Finally, pin-type a-Si:H single-junction solar cells with an optimized device structure is grown on the etched ZnO:B substrate. The corresponding electrical parameters, such as J sc , V oc and FF, are simultaneously improved compared with the solar cell deposited on as-grown ZnO:B substrate with the same fabrication process. As a consequence, a noteworthy 8.85% conversion-efficiency isachieved with an absorber layer thickness only 160nm.Highlights CZTSe thin-films were scribed using laser induced material lift-off effect. We modeled the laser energy coupling in the complex CZTSe structure. Absorber layer removal was triggered by temperature increase in Mo-CZTSe interface. Thermal effects were minimized since laser affected film was removed mechanically. No secondary phase formation of the CZTSe film was detected near the ablation zone. Abstract The thin-film Cu-chalcopyrite-based solar cell technologies are becoming more attractive due to their lower cost and optimal performance. High efficiency of small cells might be maintained with the transition to larger areas if small segments are interconnected in series in order to reduce photocurrent in thin films and resistance losses. Interconnect formation is based... on three step scribing processes and use of laser is thus crucial for performance of the device. For the first time we demonstrate the possibility to scribe the CZTSe thin-film solar cell structures with picosecond lasers. Investigations on the material lift-off effect in the CZTSe thin film were performed and the method was approved for the damage-free front-side scribing processes. Single pulse ablation and scribing experiments in the thin-film solar cell structures together with theoretical modeling of laser energy coupling in the complex CZTSe structure are presented. We found that the absorber layer removal process was triggered by a micro-explosive effect induced by high pressure of sublimated material due to temperature increase in molybdenum-CZTSe interface. This facilitated to minimize the remaining thermal effects since the laser-affected material was removed by thermo-mechanical process.Modified Surface Texturing of Aluminium-Doped Zinc Oxide (AZO) Transparent Conductive Oxides for Thin-Film Silicon Solar Cells Abstract For thin-film solar cells, the properties of the front transparent conductive oxide (TCO) electrode is an important factor in determining the overall performance of the solar cells. An efficient light trapping scheme is required to increase the optical light path and thus enhance the photon absorption within the solar cells. Improved photon absorption is necessary to increase the short-circuit current density ( Jsc ) and thus the efficiency of cells. In this paper we report the results of the texturing of aluminium-doped zinc oxide (ZnO:Al or AZO) thin films for enhanced light scattering. AZO films were deposited onto soda-lime glass sheets by in-line DC magnetron sputtering. An effective AZO texturing method was developed using diluted hydrogen chloride (HCl) and hydrogen fluoride (HF) acids through either a two-step etching or a mixed etching process, which significantly improves the uniformity of the textured surface. Texturing based on HCl and HF combines the advantagesof the large craters created by HCl etching and smaller jagged but uniform features resulting from HF etching. In this work, we demonstrate that by adopting the two-step or the mixed texturing method, it is possible to achieve high haze values of above 40% with very low surface roughness values. The combination of low surface roughness and high haze is beneficial to prevent shunting issues, and is thus very attractive for the fabrication of thin-film silicon solar cells.The influences of the oxygen contaminations on the crystal quality and performances of the evaporated polycrystalline silicon (poly-Si) thin-film solar cells prepared by solid-phase epitaxy were investigated by applying different deposition rates and base pressures. The experimental results show that although the evaporated poly-Si thin-film solar cell obtained at high base pressures (9.33×10 −5 Pa) and high deposition rate (300nm/min) has small amount of SiO 2 precipitations, it still shows the similar good material quality and performances as the cell prepared at low base pressure (1.33×10 −6 Pa) and high deposition... rate (300nm/min) with oxygen interstitials. On the other hand, the poly-Si thin-film solar cell deposited at low base pressure (1.33×10 −6 Pa) and low deposition rate (50nm/min) has large amount of SiO 2 precipitations and resulting worse material quality and hence cell performances. Therefore, the high deposition rate is desirable to maximize the solar cell performance, as well as the throughput. It is a more influential factor than the base pressure.Nanotextured Ag back reflectors were used to enhance the short-circuit current of flexible silicon thin-film solar cells with an n-i-p configuration by means of optical confinement. A nanotextured topography with a root-mean-square ( σrms ) surface roughness of 88.0nm was successfully induced by abnormal grain growth of Ag films, which was controlled by varying the deposition temperature and film thickness in a direct current (dc) magnetron sputtering process. Effective light scattering of the long wavelengths over 600nm was achieved on the nano-textured Ag back reflectors, resulting in enhanced absorption of weakly absorbing, long-wavelength light in the hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon (μc-Si:H) thin-film solar cells. Compared with similar reference cells on flat back reflectors, a 34.4% increase in the short-circuit current density ( J sc ) for an a-Si:H solar cell and an 11.9% for μc-Si:H were observed in the solar cells on the nanotextured back reflectors, with little reduction in fill factor (FF) and open circuit voltage ( V oc ). Due to the increase of the J sc by the improved light absorption at the long wavelengths, the conversion efficiency ( η ) of the a-Si:H and μc-Si:H solar cells increased from 5.59% to 7.60% and from 4.31% to 4.64%。

Enhanced Electrical and Mechanical Properties of Silver Nanoplatelet-Based Conductive Features Direct Printed on a Flexible SubstrateYoung-In Lee,†Seil Kim,‡Seung-Boo Jung,§Nosang V.Myung,†and Yong-Ho Choa*,‡†Department of Chemical and Environmental Engineering and Center for Nanoscale Science and Engineering,University of California-Riverside,Riverside,California92521,United States‡Department of Bionano Technology,Hanyang University,Ansan426-791,Republic of Korea§School of Advanced Materials Science and Engineering,Sungkyunkwan University,Suwon440-476,Republic of Korea*Supporting Informationfeatures,mechanical propertiesDirect printing methods,including dispenser,1,2gravure,3,4flexography,5and inkjet6−8printing,have been intensively investigated as low-cost“greener”alternatives to traditional subtractive photolithography to create electrical connections.In addition,these methods can write directly on various substrates (i.e.,polyimide,polyethylene terephthalate,polycarbonate,and paper)9−12to formflexible electronics including displays,13 solar cell arrays,14radio frequency identification(RFID)tags,15 and chemical sensors.16These applications require electrical contacts with excellent electrical conductance and mechanical properties.Direct printing methods generally create conductive features from ink or paste containing metals,such as micrometer or nanoparticles.Conductive features printed on flexible substrate should be electrically conductive,resist repetitive bending stress,and be properly adhered to substrates. The electrical conductivity and mechanical properties are determined by a conductive medium’s sinterability and packability during low temperature sintering and affect its composition,shape,morphology,size,and distribution.34 Currently,most research on conductive patterns printed directly onflexible substrates has been focused on enhancing electrical conductivity by controlling the diameter of conductive particles while decreasing the sintering temperature because of thermal compatibility.17−20Although nanoparticles with a high surface area to volume ratio improved the electrical properties,layer of nanoparticles into a fully densifiedfilm line without applying high pressure is still difficult because the higher surface area to volume leads to particles agglomerating and trapping gases on the surface.21Therefore,it is necessary to use dispersion agents that could inhibit the decrease in stability by coating dispersion agent on the surfaces of the nano-particles.22,23However,these dispersion agents generally have high molecular weights.Thus,a high temperature was demanded to decompose such heavy molecular materials, which hinder the application of metal nanoparticle based ink on flexible substrates.In addition,at low temperature and moderate pressure,the massflow to minimize Gibbs free energy mainly occurs at the particle surface,causing neck growth without changing particle spacing(no shrinkage or densification).Thus,fully eliminating the void between particles during sintering is impossible.Therefore,directly printing nanoparticles results in porous structures,which lead to lower conductivity and poor mechanical resistibility to external stress compared to electrochemical and physical vapor deposited patterns.This problem is more significant in noncontact direct printing,such as dispenser,aerosolized jet, inkjet,and spray coating because the only external force toReceived:May9,2013Accepted:June20,2013Published:June20,2013increase the packing density of conductive materials during printing is gravity.Thus,developing nanoengineered materials that form dense conductive features with enhanced electrical conductivity andflexural and adhesion strength by increasing the packing density is essential.One way to solve this problem is using nanoplatelets instead of nanoparticles.Metallic platelets with a micrometre scale are used in various applications,including conductive adhesives, internal multilayer ceramic capacitor electrodes,and solar cells because they do not easily agglomerate,allowing them to form conductive features with high packing densities.To use the metallic platelets as a conductive material for conductive patterns printed onflexible substrates,the platelet dimensions, including thickness,need to be optimized to nanometre scale to secure sinterability as well as packing density.To the best of our knowledge,no reports have been used metallic nano-platelets to form conductive features on aflexible substrate. Herein,we fabricated direct printed conductive features with superiorflexural strength on aflexible substrate as well as a proper electrical resistivity using silver nanoplatelet based inks without any surfactants for particle dispersion.Silver was selected as the conductive material because of its high conductivity and resistance to oxidation.In addition,the synthesis of silver nanoplatelets with a controlled shape, morphology,and dimensions has been previously re-ported.24−26The microstructure,electrical conductivity,and bending and adhesion strength of conductive features based on nanoplatelets were systematically investigated and compared to conductive features based on nanoparticles to demonstratesuperior properties.■EXPERIMENTAL PROCEDURESilver nanoplatelets were synthesized by solvothermal process that has been described in detail previously.27Poly(vinyl pyrrolidione)(PVP,MW=29000,Sigma-Aldrich)was added to N,N-dimethylformamide(DMF,>99.8%,Sigma-Aldrich)in a beaker,and mixed until completely dissolved.Silver nitrate (50mM AgNO3,>99%,Junsei)was rapidly added to the solution.After the AgNO3had completely dissolved,the solution was quickly transferred to a benchtop reactor(Model 4843,Parr Instrument Company)at160°C.After incubating for4h,samples were collected,centrifuged,and washed with water many times to remove the solution and excess PVP. The synthesized silver nanoplatelets and commercial silver nanopowders(<100nm,Sigma Aldrich)were used as materials to form conductive features on aflexible substrate.They were added and ultrasonically dispersed in ethanol to20wt% without any dispersion agents for printing inks.The ink viscosity was characterized with a viscometer(LVDV-II+CP, Brookfield Inc.).Various conductive patterns were formed on polyimidefilm(Kolon LV200,50um thickness)using dispenser printing system(SMP-III,RichStone Ltd.)composed of a syringe and needle connected to a plunger controller.The ink was loaded into a5mL plastic syringe connected to a nozzle with a capillary tip(0.2mm diameter).The nozzle ejected droplets of a constant volume of0.5μL on the polyimidefilm to fabricate patterns.The nozzle to surface distance was set to5mm.The printed patterns were annealed at200°C for1h in ambient atmosphere.Transmission electron microscopy(TEM,JEOL JEM-2100F)and atomic force microscopy(AFM;XE100,PSIA) were used to analyze the morphology and microstructure of silver nanoplatelets.X-ray diffractometry(XRD;Rigaku,CuKα)was carried out to confirm the crystal structure of the patterns.The pattern microstructures were investigated byfield emission scanning electron microscopy(FE-SEM;Hitachi S-4800)and focus ion beam equipped SEM(FIB;Tescan LYRA 1FEG).In addition,the resistivity was measured using sheet resistance obtained by a four-point probe(ATI CMT-SR2000N)and the pattern thickness.To evaluate the mechanical properties of printed silver patterns,we tested the IPCflexural resistance endurance using the IPC sliding tester (Ajeontech,Korea).Figure S1in the Supporting Information shows illustrations and images of a test sample(15mm wide, 150mm long)and the machine.The sample was loaded into the system halfway and the gap between the upper and lower samples was set to5mm.The lower plate moved forward and backward with a25mm stroke at170cycles/min,and the resistance of the silver pattern was measured at the same time. The test was carried out for959,140cycles and the changes to the microstructure were observed by FE-SEM after the test.■RESULTS AND DISCUSSIONThe silver nanoplatelets used to create conductive patterns were synthesized by a mass-productive,rapid,and simple solvothermal solution approach.The shape,size,and morphology of silver nanoplatelets can be controlled by modulating factors such as reaction time,reactant concen-trations,and reaction temperature.Images A and B in Figure1show a single triangular plate that has an edge length of approximately530nm and good crystallinity.The fringes at the edge of Figure1B are separated by2.35Å,which can be ascribed to(111)reflection.The inset in Figure1B shows a typical selected area diffraction pattern,and the spot points clearly indicate that the platelet is a single crystal with its[111] orientation parallel to the electron beam.The XRD pattern of solvothermally synthesized nanoplatelets shown in Figure3(B) also demonstrates that the basal plane(i.e.,the top crystalplane Figure1.(A)TEM image,(B)high-resolution TEM images with SAED patterns(inset image),(C)FE-SEM image with edge length distribution(inset graph)and(D)AFM image and thickness profile of silver nanoplatelets synthesized by solvothermal method.of the nanoplates)is the (111)plane because the over-whelmingly intensive di ffraction peak was located at 2θ=38.06°,which is from the (111)lattice plane of face-centered cubic (fcc)silver.Figure 1C shows a FE-SEM image and edge length distributions of silver nanoplatelets synthesized by the solvothermal method.The synthesized silver nanoplatelets were triangular and the narrow edge length distribution and average was approximately 517nm.The nanoplatelets were approximately 30nm thick by AFM analysis,shown in Figure 1D.Two inks containing silver nanoplatelets or nanoparticles were directly printed to a square shape (2cm ×2cm)on polyimide (PI)films using a dispenser printing system.The viscosities of the silver nanoplatelet and nanoparticle based inks were 5.8and 5.7cP,respectively.The surface microstructures of silver patterns from the noncontact direct printing with di fferent conductive materials and prepared by annealing at 200°C in an ambient atmosphere for 1h are shown in images A and B in Figure 2.The conductive patterns had clearly di fferentmicrostructures depending on the precursor morphology.Patterns based on silver nanoparticles had a signi ficantly higher void volume compared to patterns based on silver nano-platelets.This result directly indicates the e ffect of conductive material morphology on the microstructure of conducting pattern after sintering.Although fractional density of monosized sphere is between 0.60and 0.64,the actual density depends on the powder characteristics,namely the size and shape.28In theory,cube or cuboid particles can be packed up to 100%if arranged properly.The images in Figure 2are consistent with this idea.The cross-sectional FE-SEM images also reveal that the microstructure of annealed patterns depended on the shape of the conductive material (Figure 2C,D).For silver nanoparticles Figure 2C,the cross-sectional image and surface morphologies were the same.On the contrary,silver nanoplatelets stacked neatly on the substrate with greater packing density (Figure 2D).Panels E and F in Figure 2show the pore as black and dense areas as white colors.From these images,an image analysis program was used to calculate the pore volume.The porosities were approximately34%for nanoparticles and 12%for nanoplatelets.The particle agglomeration could also a ffect the microstructures of the patterns because there are no surfactants for particle dispersion in the inks.The nanoplatelets are more stable against the agglomeration than the nanoparticles because of their small speci fic surface area (nanoplatelets:3.83m 2/g,nanoparticles:6.96m 2/g)and platelet morphology.As shown in Figure S2in the Supporting Information,the printed pattern using the silver nanoparticle indicated agglomerated nanoparticles and a lot of voids,whereas the nanoplatelet was free of the agglomeration and the microstructure of the printed film is more compact.Figure 3shows XRD patterns for nanoparticles (Figure 3A)and nanoplatelets (Figure 3B)annealed at di fferent temper-atures (200and 300°C)in an ambient atmosphere for 1h.Five di ffraction peaks were identi fied as the (111),(200),(220),(311),and (222)planes of face-centered cubic silver in all samples.These results indicated that there were no any secondary phases in the product.For nanoplatelets,the ratio between the intensities of (111)and (200)di ffraction peaks was much higher than for commercial nanoparticles and a standard reference (in JCPDS)[(111)/(200)=125(nano-platelets),3.52(nanoparticles),and 2.15(JCDPS card #65−2871)],which is consistent with the preferred (111)facets.These XRD patterns show that (111)plane in silver nanoplatelets oriented parallel to the supporting substrate after printing.If the nanoplatelets do not arrange uniformly with the substrate,all peak intensities except (111)should increase.This phenomenon will allow for highly densepatterns.Figure 2.FE-SEM images showing the (A,B)surface and (C,D)cross-section microstructures and directly printed conductive patterns using (A,C,E)silver nanoparticles and (B,D,F)nanoplatelets after sintering at 200°C for 1h in air.(E,F)show the pore (black)and dense (white)areas.Figure 3.XRD patterns of directly printed patterns using (A)silver nanoparticles and (B)nanoplatelets before and after heat treatment at 200°C for 1h in air.The preferred stack orientation of silver nanoplatelets in the pattern remained after sintering.The pattern microstructure strongly in fluenced the electrical conductivity and flexural strength of the pattern.Table 1shows the speci fic electrical resistances of silver patterns fabricated using silver nanoplatelets and nanoparticles in this study and the comparison with those of direct printed silver patterns previously reported.Nanoplatelet patterns sintered at 200°C had the resistivity of average 7.4μΩcm (bulk silver resistivity:1.59μΩcm).This value has signi ficantly lower electrical resistivity than that of nanoparticles based patterns (30μΩcm).This result clearly shows that the electrical resistivity is functionally related to the pattern microstructure.It is clearly observed that necks between the nanoplatelets are well formed after sintering,which allows a percolation path for the electricity.Although the nanoparticles also show well-sintered structures,they have a lot of pores in the microstructure.The pores in the sintered conductive pattern may reduce the number of the percolation pathways.29,30Therefore,the electrical resistivity of the pattern based on the nanoplatelets was enhanced than that of nanoparticles because of higher packing density as shown in Figure 2.Table 1summarizes the operating parameters and the resistivity of prior works on direct printed silver patterns using silver nanoparticle based inks and this work.The resistivity of the conductive pattern typically depends on several factors,including the diameter of conductive media,a sintering temperature and time,a ramping rate for sintering,and surfactants for dispersion.20,35−37The nanoparticle-based pattern in this work exhibits a high resistivity compared with the referred results because the pattern was fabricated by relatively large nanoparticles without any surfactants for a dispersion.In the case of the nanoplatelet,the speci fic surface area of the nanoplatelets is much smaller than the nanoparticles as mentioned above,however,the printed nanoplatelet pattern had a similar or lower resistivity compared with the prior works resulting from its compact microstructure.Figures S3and S4in the Supporting Information shows the resistivity and FE-SEM images of silver patterns as a function of sintering temperature.The both films show a drastic decrease in resistivity between 150and 200°C and an additional slight decrease above 200°C.As shown in Figure S4in the Supporting Information,the patterns that sintered at relatively high temperature show a well-sintered microstructure with larger grains because the driving force for the sintering increased.The development of microstructure are consistent with the decrease in resistivity shown in Figure S3in the Supporting Information.The driving force can be also increased by decreasing the size of the conductive medium.Unfortunately,we did not investigate an e ffect of the nanoplatelet dimension and thickness on the pattern resistivityand microstructure in this study,it is expected to achieve a more densely compact and well-developed microstructure and a lower resistivity at a comparatively low sintering temperature if nanoplatelets with a smaller dimension and thickness are used.The mechanical stability of electrical circuits printed directly on a flexible substrate during external strain is one of the most important factors for flexible electronics.Figure 4shows thevariations in resistance of nanoparticle and nanoplatelet patterns under repetitive bending stress.Nanoparticle and nanoplatelet patterns di ffered markedly.For a nanoparticle pattern with a thickness of about 5.9μm,the initial resistance was 2.47Ωand it increased rapidly to 51.45Ωafter 959140bending cycles.The rate of resistance increase was about 2,080%and in case of a thinner film of 4.1μm,the resistance change rate is about 2160%(initial resistance =2.54Ω,after 959,140cycle =54.88Ω),which is similar to that of 5.9μm film.Cracks that easily formed in the pattern by bending stress likely degraded the electrical properties because theresistanceTable parison of the Electrical Resistivity of Direct Printed Silver Patterns aAg NPs 50260/3PVP 1632Ag NPs 40180/602polymer520Ag NPs 20250/9010poly(acrylic acid)5219Ag NPs 20160/30PVP 8.833Ag NPs 100200/6010none 30±3.65this work AgNTsE:518,T:30200/6010none7.4±0.65this workaNPs,nanoparticles;NTs,nanoplatelets;E,edge;T,thickness;EG,ethylene glycol;PVP,polyvinylpyrrolidone.Figure 4.Graphs showing resistance variation of conductive patterns formed by (A)silver nanoparticles and (B)silver nanoplatelets at 200°C under repetitive bending stress.sharply increased throughout the test.In contrast,the electrical resistance of nanoplatelet patterns shows a small change rate as shown in Figure 4B.The result on the nanoplatelet patterns with a thickness of 3.3μm was constant in the entire bending cycles except for the small increase in the resistance after the 900000th cycle.The resistance increased a mere 200%from 2.95to 6.01Ωafter 959140bending cycles.Therefore,the resistance change due to repetitive bending stress is connected to the microstructures.The silver nanoparticle patterns have to be vulnerable to bending stress because the many pores crack and move easily,thus the electrical resistivity increased sharply after bending stress.The dense microstructure of nanoplatelet patterns,however,withstood the bending stress by minimizing cracking and movement.Figure 5shows the microstructure of silver patterns after inducing repetitive bending stress.Many cracks about 50μmlong were observed throughout the silver nanoparticle patterns.On the other hand,cracks of nanoplatelet patterns were di fficult to find.Images show that crack formation likely causes the resistance increases (Figure 4),and cracks are minimized by using nanoplatelets.The mechanical stability test and FE-SEM images indicate that nanoplatelet patterns with dense micro-structure have excellent resistivity on repetitive bending stress compared with nanoparticles.■CONCLUSIONSIn conclusion,we demonstrated highly dense conductive patterns with excellent electrical and mechanical properties using silver nanoplatelets as the conductive materials.Nano-platelets stack neatly on the substrate after direct printing,which minimizes void formation.The direct printed nano-platelets have signi ficantly lower electrical resistivity than nanoparticles (7.4μΩcm compared to 30μΩcm).In addition,nanoplatelet-based conductive patterns have excellent stability on external repetitive bending stress because they do not crack upon external bending stress.Improved electrical resistivity and mechanical stability can be attributed to the dense microstructure resulting nanoplatelet conductive materi-al.These findings can be readily applied to various flexible electronics,including solar cells,displays,RFID,and sensors.ASSOCIATED CONTENT*Supporting Information Illustrations of the IPC flexural resistance endurance test machine and sample,real optical images of direct printed Ag pattern,FE-SEM images of the Ag patterns before sintering,and resistivity and FE-SEM images as a function of sintering temperature.This material is available free of charge via the Internet at .■AUTHOR INFORMATIONCorresponding Author*E-mail:choa15@hanyang.ac.kr.Tel.:+82-31-400-5650.Fax:+82-31-418-6490.NotesThe 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In fluence of micro-blasting on the microstructure and residual stresses of CVD κ-Al 2O 3coatingsC.Barbatti a ,b ,J.Garcia c ,d ,⁎,R.Pitonak e ,H.Pinto a ,A.Kostka a ,A.Di Prinzio f ,M.H.Staia f ,A.R.Pyzalla caMax-Planck-Institut für Eisenforschung GmbH,40237Düsseldorf,GermanybCorus Research,Development and Technology,P.O.Box 10000,1970IJmuiden,The Netherlands cHelmholtz Zentrum Berlin fuer Materialien und Energie GmbH,14109Berlin,Germany dRuhr Universität Bochum,Materials Technology,44780Bochum,Germany eR&D,Boehlerit GmbH &Co.KG,8605Kapfenberg,Austria fSchool of Metallurgy and Materials Science,Universidad Central de Venezuela,P.O.Box 47885,Los Chaguaramos,1041Caracas,Venezuelaa b s t r a c ta r t i c l e i n f o Article history:Received 10February 2009Accepted in revised form 3June 2009Available online 17June 2009Keywords:CVD κ-Al 2O 3Cemented carbides Micro-blasting Residual stressesSynchrotron X-ray diffractionCemented carbides coated with CVD multilayers are commonly used in metal cutting turning and milling operations.For many applications,a micro-blasting finishing procedure based on an impact treatment of the surfaces is carried out in order to smooth the coated surface and reduce sharp cutting edges.In this work,micro-blasting with corundum in aqueous solution at pressures between 0.05and 0.3MPa was applied to CVD TiN/Ti(C,N)/κ-Al 2O 3multilayer coatings deposited onto cemented carbides in order to investigate its in fluence on the micro-topography,microstructure and residual stresses.The results showed that the micro-blasting reduces the surface roughness and affects the coating thickness.TEM investigations revealed no signi ficant changes on the microstructure of the κ-Al 2O 3top layer.Synchrotron X-ray investigations showed that the residual stress state of the as-deposited κ-Al 2O 3top layer is not affected by the micro-blasting treatment under the conditions investigated.©2009Elsevier B.V.All rights reserved.1.IntroductionCoated cemented carbides are commonly used in the metal cutting industry for machining of iron-base alloys.In order to increase the tool life of cutting inserts,cemented carbides are coated with wear resistant coatings by chemical vapour deposition (CVD)or physical vapour deposition (PVD).Al 2O 3is considered an ideal coating layer in high-speed metal cutting due to its high chemical stability,high hardness and favourable thermal properties at the high temperatures reached during metal cutting [1–3].Due to the mixed ionic and covalent bonding,the material is highly insulating [4,5],thus being usually applied as a top layer to act as a thermal and diffusion barrier.The CVD technique is commonly employed since it is the only deposition method that allows the economical large-scale production of high-quality alumina coatings [6].In addition to the stable α-Al 2O 3,alumina can be obtained in two other metastable modi fications by CVD,namely κ-Al 2O 3and γ-Al 2O 3[7,8].A typical multilayer combination is that of Ti(C,N)to provide wear resistance,followed by an Al 2O 3top layer,which enhances the thermal resistance of the tool.Due to adhesion problems between the Ti(C,N)and the Al 2O 3coating,the use of an intermediate layer made of Ti(C,N,O)is proposed[9,10].These intermediate layers of Ti-based compounds favour the nucleation of κ-Al 2O 3[11,12].More recently,a novel method for producing an adequate bonding of the Al 2O 3top layer onto the Ti(C,N)by the formation of a nano-transition needle-like phase arrangement has proved to be advantageous [13].This method also leads to the formation of κ-Al 2O 3.Micro-blasting is a finishing procedure based on an impact treatment of the surfaces.Generally,this procedure is applied to coatings to clean,smooth the surface and reduce sharp cutting edges [14–16].This process involves the use of high pressure and abrasive powders.Besides,there is still the possibility of achieving an attractive side effect,namely,the introduction of bene ficial compressive residual stresses.Previous works showed that micro-blasting of ground and polished hard metal substrates can increase the cutting performance of coated tools mainly due to film adhesion enhancement [17–20].Moreover,it has been recently shown that micro-blasting treatment of PVD coatings deposited on hard metal substrates improves its residual stress with regard to fatigue strength and cutting performance of the coated tool [21].In [22,23]it is reported that compressive residual stresses were induced on PVD/CVD multilayers by micro-blasting with pressures between 0.2and 0.6MPa.Holzschuh reports in [24]a method to introduce compressive stresses in CVD multilayers by removing the TiN top layer of a Ti(C,N)/Al 2O 3/TiN multilayer coating by micro-blasting,however,without any mention of the blastingSurface &Coatings Technology 203(2009)3708–3717⁎Corresponding author.Helmholtz Zentrum Berlin fuer Materialien und Energie GmbH,14109Berlin,Germany.Tel.:+492343228229.E-mail address:jose.garcia@helmholtz-berlin.de (J.Garcia).0257-8972/$–see front matter ©2009Elsevier B.V.All rights reserved.doi:10.1016/j.surfcoat.2009.06.021Contents lists available at ScienceDirectSurface &Coatings Technologyj o u r n a l h om e p a g e :w w w.e l s ev i e r.c o m /l o c a t e /s u r fc o a tconditions employed.In[22–24]improvements of tool life of micro-blasted Al2O3coated cutting inserts in metal cutting are presented. The reason for the increment of the tool life is reported to be related to the introduction of compressive residual stresses on the Al2O3top layer.Although not mentioned in their publications,it is to be understood from the results presented that the authors worked with α-Al2O3coatings.Nevertheless,in spite of the many publications,no systematic study on the influence of micro-blasting pressure on Al2O3coating is found in the literature.In this work,we applied micro-blasting to CVD multilayer TiN/Ti (C,N)/κ-Al2O3coatings.The micro-blasting pressure range varies between0.05and0.3MPa.We aim at investigating systematically the influence of the blasting pressure on the micro-topography and the possibility of inducing compressive residual stresses on theκ-Al2O3 top layer.The microstructure and residual stress state of theκ-Al2O3top layer were investigated for the as-deposited and micro-blasted conditions by scanning electron microscopy,transmission electron microscopy,synchrotron as well as laboratory source X-ray diffraction and roughness measurements.2.Experimental2.1.Substrate and coatingsThe coatings were deposited onto cemented carbide substrates (90wt.%WC–10wt.%Co)with a size of14mm×14mm×5mm, produced by state-of-the-art powder metallurgy sintering techniques.A TiN/Ti(C,N)/κ-Al2O3multilayer was applied on the hard metal substrate by CVD in a standard hot-wall CVD reactor working at 1015°C and15kPa.The TiN and Ti(C,N)layers were deposited from the gas mixture TiCl4–CH4–N2–H2.The Al2O3layer was deposited on top of the Ti(C,N)layer from the gas mixture AlCl3–ClH2–CO2.Due to the deposition conditions employed,κ-Al2O3was produced as a top coating layer.2.2.Micro-blastingAfter deposition,the coatings were subjected to a micro-blasting treatment performed using an injector-type system in a commercial industrial blasting furnace.Standard industrial parameters were employed.The grit blasting material used was320-mesh(average diameter within~50µm)corundum shots in aqueous solution.The micro-blasting treatment was carried out for30s to ensure full coverage of the surfaces.The pressure was varied within the range from0.05MPa to0.3MPa in steps of0.05MPa.2.3.MicroscopyScanning electron microscopy(SEM)was performed on non-polished surfaces and fractured cross-sections.Specimens for transmission electron microscopy(TEM)analyses were prepared by using a gallium source JEOL JEM-9320focused ion beam(FIB)system operating at30kV.A JEOL2200F TEM/STEM operating at200kV and equipped with an EDX system was used for studying the microstructure of coatings in the as-deposited and micro-blasted state.2.4.RoughnessThe surface roughness(R a and R z)of as-deposited and micro-blasted coatings was determined from atomic force microscopy pictures.Four areas were measured in order to determine an average value.The measurements were carried out in a Nano-scratch tester equipped with an atomic force microscope(CSM Instruments).2.5.Phase and residual stress analysesIn order to assess the phase constitution within the as-deposited and micro-blasted coatings,X-ray diffraction(XRD)diffractograms were obtained using synchrotron radiation at the experimental station G3at DORIS III at HASYLAB at DESY,Hamburg.The radiation energy was 6.9keV(λCo=1.7904A˚´).The beam size was set as 4mm×1mm.The residual stresses within theκ-Al2O3coatings were determined on a laboratory four-circle diffractometer operating with Co–K a radiation and parallel-beam geometry using the sin2ψmethod[25]. Owing to the weak macroscopic texture of theκ-Al2O3coating, unrestricted lattice spacing measurements could be performed for24 sample directions defined by the inclination angleψbetween0°and 89.8°at the azimuthsφ=0°and180°.Considering the stress state in the coatings to be biaxial and of rotational symmetry,the fundamental relationship of X-ray stress analysis can be solved to provide the depth-dependence of the in-plane residual stressesσ//[26]:σ==τeffðÞ=eψτeffðÞ12s21ÀÁð1Þwhereɛψis the measured lattice strain,σ//is the in-plane residual stress,τeff is the information depth,and1/2s2and s1are the phase-specific diffraction elastic constants(DEC).The concept of effective information depthτeff is usually applied in diffraction studies of thinfilms to define the depth from which the diffraction information comes,since the penetration depthτof the radiation into a certain material may be much larger than thefilm thickness.According to its definitionτeff can be tuned within thefilm thickness by changing theψ-angle[27]:τeff=R DzÁe−zτd zRe−zτd z=τ−De−Dτ1−e−Dτð2Þwhereτis the average penetration depth for an infinitely thick sample,which is a function of theψ-tilt,and D is the thickness of theκ-Al2O3layer.In this approach the maximum achievable information depth approaches the limit of half layer thickness(D/2) as the ratio D/τin Eq.(2)decreases towards zero.The lattice strains were measured for the{135}diffraction line of κ-Al2O3.This reflection was chosen based on a compromise between the ease for separating this line from neighboring ones,its intensity and the highest possible2θ-angle.The DEC were estimated using the mechanical values of Young's modulus E=361.7GPa and Poisson's ratioν=0.24forκ-Al2O3at room temperature available in[5].The integral breadth of the selected reflection was also determined as a function of the micro-blasting conditions.This quantity is related to the density of crystalline defects(dislocations,stacking faults)and small size of crystallites(i.e.domains over which diffraction is coherent)[28].The integral breadth for each condition represents an average on the results obtained at differentψ-angles byfitting the {135}diffraction lines using pseudo-Voigt functions.3.Results3.1.Microstructure of the as-deposited coatingsThe as-deposited layer system is shown in Fig.1.The CVD TiN/ TiCN/κ-Al2O3layers show good adhesion to the cemented carbides, hence no pores,brittle phase formation nor spallation between the substrate and the coating are observed.The layer thickness is homogeneous across the coating,the thickness of the TiN is of about 0.2µm,for the intermediate Ti(C,N)layers is about3µm and the thickness of theκ-Al2O3is about4µm±0.05.3709C.Barbatti et al./Surface&Coatings Technology203(2009)3708–3717The alumina layer is composed of columnar grains that grow directly from the nucleation surface (here,the intermediate Ti(C,N)layer).The length of the columnar grains is mostly equivalent to the thickness of the alumina layer.A change in the morphology towards the surface can be observed,with the formation of hexagonal-shaped grains (Fig.1b and c).Some cracks (mainly transgranular)can also be observed.They are typical cracks as a consequence of the different thermal expansion coef ficients between the substrate and the coating and cannot really be avoided in commercial CVD cutting inserts.Several isolated large grains with average diameter larger than 5µmformed as a single crystal or a polycrystalline structure in a random distribution throughout the surface (Fig.2).Their number increases towards the edge of the inserts.Crack initiation seems to be associated with these outgrowths.The average surface roughness R a measured was 0.110±0.008(Table 1).The penetration depth of the X-rays in alumina is about 18µm.Hence,we have full penetration of the radiation into the coating system.The X-ray diffraction (XRD)patterns for the as-deposited sample are shown in Fig.3.The contribution of the substrate is also registered,indicated by the peaks associated with WC re flections.The XRD measurements also reveal that the intermediate layer is composed of Ti (C 0.3N 0.7).The intensity ratio between peaks shows no marked texture in the layers.Although the observation of the κ-→α-Al 2O 3phase transformation already during the deposition process is generally reported in literature [29],there is no evidence for the occurrence of such transformation,since the XRD diffractograms only revealed re flections associated with κ-Al 2O 3.This indicates that the super ficial cracks observed in the as-deposited coatings arise upon cooling due to the differences in thermal coef ficient between the coating and the substrate,and not originating from volume contraction that occurs in phase transformation.Fig.4shows a STEM micrograph of the as-deposited coating.The darkest areas at the bottom correspond to the cemented carbide substrate (WC grains are seen in black).The TiN layer with a thickness of 0.5µm lies adjacent to the substrate.Onto the TiN layer,the Ti(C,N)layer shows a changing grain morphology (Fig.4),making it appear as two distinct structures.The first sub-layer consists of columnar grains with a width of about 0.1µm.The following sub-layer has signi ficantly smaller grains with a needle-like morphology and appears randomly oriented.The uppermost layer consists of κ-Al 2O 3(in lighter contrast)and shows grains grown along the CVD deposition direction perpendicular to the substrate.The columnar microstructure istypicalFig.2.SEM image (BSE mode)of κ-Al 2O 3surface topography (top view)after coating.Isolated large Al 2O 3grains (with average size of 5µm)form in a random distribution throughout the surface.Crack initiation seems to be associated with these large grains (see arrows around the large Al 2O 3grain).Table 1Values of R a ,R z and thickness for the κ-Al 2O 3top layer as a function of micro-blasting pressure.Micro-blasting pressure [MPa]R a roughness [µm]R z roughness [µm]Thickness [µm]00.110±0.0080.690±0.04 4.20±0.050.050.096±0.0050.540±0.04 4.20±0.050.10.079±0.0060.480±0.04 4.00±0.050.150.038±0.0040.190±0.03 3.40±0.050.20.045±0.0030.250±0.03 3.00±0.050.250.074±0.0040.440±0.03 2.50±0.050.30.084±0.0040.540±0.042.50±0.05Fig.1.SEM images of (a)fracture cross-section of the coated cemented carbide,(b)top view of the surface topography of as-deposited CVD κ-Al 2O 3coating and (c)higher magni fication (top view)of the surface topography showing hexagonal-shaped grains.3710 C.Barbatti et al./Surface &Coatings Technology 203(2009)3708–3717for coatings deposited at low gas pressures and low temperatures compared to the melting point temperature [30].Besides the STEM mode,conventional Bragg diffraction contrast TEM was applied to investigate the evidence of defects within the κ-Al 2O 3top layer.A TEM micrograph in bright field (BF)mode is shown in Fig.5a.No dislocations but a high concentration of planar defects (twin-related faults)were observed (Fig.5a).All obtained electron diffraction patterns(e.g.Fig.5b)only reveal the presence of the κ-Al 2O 3phase.No evidence of phase transformation was obtained.The two possible variations of alumina (i.e.the metastable κ-Al 2O 3and the stable polymorph α-Al 2O 3)have strikingly different symmetry,which could have been easily distinguished if the latter were present.EDX analysis reveals almost no chemical intermixing,which suggests good separation of the layers.3.2.Microstructure of micro-blasted coatingsMicrographs of surface morphology and fracture cross-section of the samples micro-blasted at pressures in the range 0.05–0.15MPa are presented in Fig.6.Lower micro-blasting pressures,i.e.0.05and 0.1MPa cause no signi ficant changes in grain morphology,although a decrease in the average roughness is measured.At blasting pressures as low as 0.05MPa few isolated areas already appear deformed.As from 0.15MPa,signi ficant loss of coating material begins to occur and the number of cracks increases.Crack propagation typically occurs in a transgranular mode,but seems to be con fined to the near-surface zone of the upper coating.Micro-blasting at 0.2MPa causes a flattening of the grains and flaking of the coating as a consequence of the strong abrasive effect due to micro-blasting (Fig.7).Higher micro-blasting pressures (0.25and 0.3MPa)lead to strong changes in the surfacemicro-topographyFig.3.X-ray diffractogram of the as-deposited κ-Al 2O 3/Ti(C,N)coatings taken at ψ=0°with synchrotron radiation energy of 6.9keV (λCo =1.7904A˚´).The arrow indicates the position of the κ-Al 2O 3(135)re flection used for the residual stressevaluation.Fig. 4.(a)STEM micrograph showing the cross-section microstructure of the as-deposited coating.(b)Higher magni fication of the top κ-Al 2O 3layer.Fig.5.TEM micrograph in bright field (BF)mode showing planar defects within the as-deposited κ-Al 2O 3layer.(b)Selected area diffraction pattern (SADP)corresponding to κ-Al 2O 3.3711C.Barbatti et al./Surface &Coatings Technology 203(2009)3708–3717and an increase in the number and length of the cracks.The microstructure of the Ti(C,N)intermediate layer does not seem affected by the impact of the alumina shots.STEM micrographs of the cross-section microstructure of coatings micro-blasted at 0.1MPa and 0.3MPa are shown in Fig.8.By comparing the microstructure of the micro-blasted samples at different conditions,the only difference corresponds to the signi ficant reduced thickness of the alumina layer micro-blasted at 0.3MPa.The in fluence of micro-blasting pressure on the thickness of the κ-Al 2O 3layer is shown in Table 1.On the other hand,the results clearly show that the micro-blasting does not affect the adherence of the layer.Moreover,the Ti(C,N)is not affected by the mechanical treatment,the reduction in layer thickness being con fined to the top alumina layer.The TEM micrograph in BF mode (Fig.8c)shows the typical planar defects also observed within the alumina layer of the micro-blasted coatings (here we only show the example of the sample micro-blasted at 0.3MPa).The concentration of the twin-related faults observed in samples in all conditions seems to be identical,which directly suggests that the micro-blasting process has no in fluence on the defect density observed in the top κ-Al 2O 3layers.Besides,not a single dislocation was observed in the analyzed micro-blasted top κ-Al 2O 3layers.Micro-blasting leads to a decrease in the roughness of the alumina coating,showing a minimum at blasting pressures between 0.15and 0.2MPa (Table 1).Increasing the blasting pressure above 0.2MPa increases the roughness due to deterioration of the coating layer.ThisFig.6.SEM micrographs showing the changes on the κ-Al 2O 3thickness (fracture cross-sections)and surface topography (top view images)as a function of micro-blasting pressure:(a)and (b)at 0.05MPa;(c)and (d)at 0.1MPa;(e)and (f)at 0.15MPa.3712 C.Barbatti et al./Surface &Coatings Technology 203(2009)3708–3717is related to the extensive loss of the top layer material that occurs with increasing pressures.The removal of top coating material causes an increase in the line intensity of the WC re flections,since more contribution from the substrate is being registered (Fig.9).No changes in the intensity ratio between peaks with increasing micro-blasting pressures are observed.3.3.Residual stress analysesThe sin 2ψcurves of the κ-Al 2O 3layers in the as-deposited and micro-blasted (at 0.1and 0.3MPa)conditions are presented in Fig.10.The obtained d –sin 2ψdistributions are shown to be linear with positive slopes up to sin 2ψ~0.92in all conditions,indicating the presence of average residual stresses of tensile nature within the κ-Al 2O 3layer,which still predominate in the micro-blasted state.On top of the coatings (at large ψangles,thus,at small penetration depths),however,the d ψhkl–sin 2ψdistributions tend to curve downwards,suggesting the presence of near-surface gradients of the in-plane residual stresses in the as-deposited as well as in the micro-blasted conditions.ψ-splittingin the d ψhkl–sin 2ψplots does not occur,indicating the absence of shear stress components in all cases investigated.The in-plane residual stresses averaged over the entire κ-Al 2O 3layer are 355±41MPa,349±45MPa,and 392±39MPa in the as-deposited,0.1and 0.3MPa conditions,respectively (Table 2).Based on the sin 2ψdistributions (Fig.10),the in-depth distribution of the residual stresses in the κ-Al 2O 3coatings was determined using Eq.(1).The stress-depth pro files for the as-deposited and micro-blasted coatings are similar as presented in Fig.11.In the as-depositedstate,Fig.7.SEM micrographs showing the changes on the κ-Al 2O 3thickness (fracture cross-sections)and surface topography (top view images)as a function of micro-blasting pressure:(a)and (b)at 0.2MPa;(c)and (d)at 0.25MPa;(e)and (f)at 0.3MPa.3713C.Barbatti et al./Surface &Coatings Technology 203(2009)3708–3717the residual stress in the ‘bulk ’of the layer was found to be σ//(τ≈1.5µm)=699MPa,whereas the obtained value at the outer surface decreases down to σ//(τ≈0)=−32MPa.This indicates thatthe stresses become gradually less tensile towards the free surface,eventually turning into low compression at the surface.A similar behaviour is observed for the specimen micro-blasted at 0.1MPa:the tensile residual stress within the coating is slightly lower σ//(τ≈1.5µm)=603MPa,whereas at the surface low compressive residual stresses σ//(τ≈0)=−42MPa are also obtained.For the specimen micro-blasted at 0.3MPa,the stress values are σ//(τ≈1.5µm)=546MPa and σ//(τ≈0)=153MPa within the coating and close to the surface,respectively (Table 2).The analysis of the average integral breadth of the {135}diffraction line of κ-Al 2O 3suggests that the density of lattice imperfections does not signi ficantly increase with increasing micro-blasting pressures.This information corroborates the TEM investigations,which reveal low dislocation densities,even with increasing micro-blasting pressures.4.Discussion4.1.Effect of micro-blasting on microstructure and roughnessOur results indicate that the micro-blasting procedure only affects the κ-Al 2O 3top coating layer.SEM and TEM images show that there are no disturbances in the integrity of the intermediate Ti(C,N)layer.Strong deformation of the coatings appears as a flattening effect on the near-surface zone,mainly at pressures higher than 0.1MPa.ThisFig.8.STEM micrographs showing the cross-section microstructure of coatings micro-blasted at (a)0.1MPa and (b)0.3MPa.(c)TEM micrograph (BF)showing planar defects within the alumina layer of the coating micro-blasted at 0.3MPa.Fig.9.X-ray diffractograms of micro-blasted coatings as a function of micro-blasting pressure showing no change in the intensity ratio between peaks with increasing micro-blasting pressures.3714 C.Barbatti et al./Surface &Coatings Technology 203(2009)3708–3717flattening is produced on the one hand by the overlapping of the several localized deformations caused by the impact of the alumina shots on the surface.On the other hand,the impacts also remove material from the alumina coating,which also results in a smoothing of the protruding irregularities on the surface (Table 1).The lower roughness in the contact zone of the coating decreases the mechanical contact between asperities of the tribological pair tool-workpiece.This leads to a lower friction coef ficient and thus,a contribution for extended tool life of the inserts.4.2.Origin of stresses and defects4.2.1.Stress development upon CVD depositionCVD coatings are known to evolve relevant thermal mismatch residual stresses upon cooling from the high deposition temperatures [31].The strain and stress state in the layers change due to thermal strain introduced by differences in the coef ficients of thermal expansion between the individual layers and the substrate.The maximum thermal stresses induced by cooling (without taking stress relieving processes into account)can be estimated by using the Dietzel equation [32]:σc =E c αc −αs ðÞΔT f g =1−v c ðÞ+1−v s ðÞ=E s ½ d c =d s f gð3Þwhere αis the linear coef ficient of thermal expansion,νis the Poisson ratio,E is the Young's modulus,d is the thickness,c stands for coating and s for substrate.The thermal expansion coef ficient(TEC)Fig.10.The sin 2ψdistributions of the κ-Al 2O 3(135)re flection for φ=0°of the coatings (a)as-deposited,(b)micro-blasted at 0.1MPa and (c)micro-blasted at 0.3MPa.Table 2Values of internal stresses in the κ-Al 2O 3top layer as a function of micro-blasting pressure.Micro-blasting pressure [MPa]Average in-plane residual stresses [MPa]Stress value near the outer surface of κ-Al 2O 3[MPa]Stress value in the “bulk ”of κ-Al 2O 3[MPa]0355±41σ//(τ≈0)=−32σ//(τ≈1.5µm)=6990.1349±45σ//(τ≈0)=−42σ//(τ≈1.5µm)=6030.3392±39σ//(τ≈0)=153σ//(τ≈1.5µm)=546Fig.11.Depth pro file of the in-plane residual stresses obtained from the evaluation of the sin 2ψdistributions shown in Fig.11for the coatings (a)as-deposited,(b)micro-blasted at 0.1MPa and (c)micro-blasted at 0.3MPa.3715C.Barbatti et al./Surface &Coatings Technology 203(2009)3708–3717ofκ-Al2O3and Ti(C,N)usually lies within8.0–9.0×10−6K−1[33], whereas in the case of WC–Co cemented carbides it is in the range within 4.0–7.0×10−6K−1depending on the composition[34]. Hence,tensile stresses will necessarily develop in theκ-Al2O3coating sinceακ-Al2O3Nαs.Our results clearly show that average tensile stresses develop within theκ-Al2O3layer,indicating that thermal strains represent the major source of residual stresses in the present case.The low compressive stress values towards the surface could be attributed to the relaxation of the tensile residual stresses existent in the‘bulk’of the layer,since the interaction between the substrate and the coatings tends to decrease when approaching the free surface. Besides,the crack propagation,which seems to be confined to the zone closest to the surface,might also play a role in the relaxation mechanism.4.2.2.Stresses and defects induced by micro-blastingThe residual stresses are generally classified into three types: macro-stresses,micro-stresses,and root mean square(r.m.s.)stresses [25].Macro-stresses often develop during sample manufacturing, extending homogeneously over macroscopic distances,i.e.several grains.In contrast,micro-stresses arise over microscopic volumes, typically grain sizes,due to the mismatches in thermal and mechanical properties of the individual phases or grain orientations. Both cause diffraction line shifts since they are related to average lattice strains of grains with specific orientations.As discussed in the Section4.2.1,they are of thermal origin in the present case,and are not affected by the applied micro-blasting treatment.The third type of stresses(r.m.s.stresses),which is inhomogeneous within subgrains or crystallites due to the presence of lattice imperfections and vary on the atomic scale,does not induce line shifts but only diffraction line broadening,since any disturbance in the regularity of the crystal lattice is reflected in lattice parameter fluctuations.Typical causes for diffraction line broadening are therefore lattice distortions that arise from crystal defects(e.g.dislocations and planar faults),changes in the diffraction coherence length(domain size)and domain-size distribution[28].Based on evidences provided by both TEM and XRD investigations, we conclude that theκ-Al2O3top layer does not undergo plastic deformation during micro-blasting.In particular,TEM imaging indicates practically the absence of dislocations,even at a micro-blasting pressure as high as0.3MPa,which promotes extensive loss of theκ-Al2O3layer and strong changes in layer micro-topography.Planar defects in the form of twin-related faults are the only type of crystalline defects observed and already predominate in the as-deposited state,the density of which is not affected by the micro-blasting process.The crystal structure of the metastableκ-Al2O3is well established. It has an orthorhombic crystal structure(space group Pna21)with lattice parameters a=4.844Å,b=8.330Å,c=8.955Åformed from a pseudo-closed-packed stacking ABAC of oxygen atoms with Al in octahedral and tetrahedral environments in a3:1ratio[35,36]. Supposedly,due to the rather complex crystalline structure,distortion of the lattice occurs differently according to the crystallographic direction leading to twinning as the predominant deformation mechanism inκ-Al2O3phase in contrast toα-Al2O3,in which dislocation is the type of recurrent defects observed.5.ConclusionsMicro-blasting at pressures ranging from0.05up to0.3MPa was applied to CVDκ-Al2O3/Ti(C,N)/TiN multilayer coatings in order to investigate the potentiality of this procedure to control the surface micro-topography and modify the residual stress state of the coating. Our investigations reveal that:1.Theκ-Al2O3growth occurs in columnar direction,perpendicular tothe substrate.Noκ→αphase transformation of the Al2O3isinduced by micro-blasting according to both synchrotron X-ray diffraction and TEM studies.2.The effects of the micro-blasting treatment on the TiN/Ti(C,N)/κ-Al2O3multilayer under the conditions investigated are con-fined to theκ-Al2O3top layer,as revealed by the TEM and STEM investigations.3.Increasing the micro-blasting pressure leads to the formation andpropagation of cracks.SEM and TEM investigations show that crack propagation is confined to the zone closest to the surface.4.Increasing micro-blasting pressure leads to a reduction in roughnessfrom R a:0.110±0.008/R z:0.690±0.04in the as-deposited coatings up to R a:0.038±0.004/R z:0.190±0.03in coatings micro-blasted at0.15MPa,which is mainly associated with the loss of coating material.Blasting pressures above0.2MPa lead to coating degradation.5.TEM investigations showed high density of planar defects in theκ-Al2O3in the form of twin-related faults(Figs.5and8).TEM and XRD investigations reveal that theκ-Al2O3top layer does not undergo plastic deformation during micro-blasting.6.The residual stresses are of tensile nature and thermally induced andare not affected by the applied micro-blasting treatment.The average stress values over theκ-Al2O3layer are355±41MPa,349±45MPa, and392±39MPa in the as-deposited,0.1MPa and0.3MPa conditions.These tensile stresses ease towards the free surface.It can be in general concluded that,under the conditions investigated,the more remarkable effect of the micro-blasting treat-ment on theκ-Al2O3top layer was a reduction of the surface roughness for blasting pressures up to0.15MPa and a strong coating degradation for blasting pressures above0.2MPa.Neither the morphology nor the residual stress state of theκ-Al2O3top layer was affected by the micro-blasting.This is a main difference in the response to the treatment compared with the reported values forα-Al2O3[22,24,26],pointing out that the generation of compressive internal stresses by micro-blasting depends strongly on the crystalline structure of the Al2O3phase.This observation may be supported by previous investigations indicating a higher degree of plasticity ofα-Al2O3[37]compared toκ-Al2O3.On the other hand,the different physical characteristics of the metastable CVD κ-Al2O3compared to the CVDα-Al2O3,such as a smaller grain size,a lower pore density and an epitaxial growth,may also have an influence on the internal stress conditions after micro-blasting treatment[35]. AcknowledgementsThe authors(J.Garcia and H.Pinto)thank thefinancial support of the DFG project444Bra-113/25/0-1to carry out part of this work.Anna di Prinzio thanks ADEMAT Network,Alfa-project Nr.II-0240-B1-AT-RT-CT forfinancial support.Dr.A.Rothkirch(Hasylab),Dr.C.Juricic and Mr.P. Brito(MPIE)are kindly acknowledged for their support during the synchrotron X-ray measurements.Thanks to Mr.U.Föckeler(Ruhr Universität Bochum)for atom force microscopy measurements. References[1]F.Bunshah,Handbook of Hard Coatings,Noyes Publications/William AndrewPublishing,LLC,Norwich,New York,USA,2001.[2]P.K.Mehrothra,D.T.Quinto,High Temp.High Press.18(1980)199.[3]B.M.Kramer,N.P.Suh,J.Eng.Ind.102(1980)303.[4]R.H.French,J.Am.Ceram.Soc.73(1990)477.[5]B.Holm,R.Ahuja,Y.Yourdshhyan,B.Johansson,B.I.Lundqvist,Phys.Rev.,B59(1999)12777.[6]S.Ruppi,Int.J.Refract.Met.Hard Mater.23(2005)306.[7]S.Ruppi,rsson,Thin Solid Films388(2001)50.[8]S.Ruppi,rsson,A.Flink,Thin Solid Films516(2008)5959.[9]H.Holzschuh,Patent US6,436,519B2,20.08.2002.[10]H.Halvarsson,S.Vuorinen,Surf.Coat.Technol.56(1993)165.[11]M.Halvarsson,H.Nordén,S.Vuorinen,Surf.Coat.Technol.68–69(1994)266.[12]M.Halvarsson,J.E.Trancik,S.Ruppi,Int.J.Refract.Met.Hard Mater.24(2006)32.[13]R.Pitonak,J.Garcia,R.Weissenbacher,K.Udier,Patent EP1948842,30.07.2008.[14]D.M.Kennedy,J.Vahey,D.Hanney,Mater.Des.26(2005)203.[15]J.Qu,A.J.Shih,R.O.Scattergood,J.Luo,J.Mater.Process.Technol.166(2005)440.3716 C.Barbatti et al./Surface&Coatings Technology203(2009)3708–3717。

全文分为作者个人简介和正文两个部分：作者个人简介：Hello everyone, I am an author dedicated to creating and sharing high-quality document templates. In this era of information overload, accurate and efficient communication has become especially important. I firmly believe that good communication can build bridges between people, playing an indispensable role in academia, career, and daily life. Therefore, I decided to invest my knowledge and skills into creating valuable documents to help people find inspiration and direction when needed.正文：蝴蝶的外形特征和生活方式英语作文全文共3篇示例，供读者参考篇1The Wondrous World of ButterfliesButterflies are one of the most enchanting creatures on our planet. With their delicate wings adorned in vibrant hues and intricate patterns, they seem to flutter straight out of a fairytale.As a student of nature, I have always been captivated by these graceful insects and the remarkable journey they undertake in their brief but extraordinary lives.The Physical MarvelA butterfly's body is a true marvel of evolution, meticulously designed for its unique lifestyle. At first glance, one may be struck by the striking beauty of its wings, which serve as a canvas for nature's artistry. However, upon closer inspection, it becomes evident that these wings are not merely ornamental but highly functional.Each wing is composed of two layers of chitin, a strong yet lightweight material, allowing the butterfly to take flight with remarkable agility. The wing surface is covered in tiny scales, overlapping like shingles on a roof, which create the mesmerizing colors and patterns we admire. These scales serve a dual purpose, not only enhancing the butterfly's beauty but also aiding in temperature regulation and camouflage.Underneath the wings lies a slender body segmented into three main parts: the head, thorax, and abdomen. The head houses a pair of large compound eyes, capable of detecting even the slightest movements, and a long, coiled proboscis used for sipping nectar from flowers. The thorax is the powerhouse,housing the muscles that control the wing movements, while the abdomen contains the vital organs necessary for the butterfly's survival.Perhaps the most fascinating aspect of a butterfly's physiology is its ability to undergo an incredible transformation from a humble caterpillar to a winged wonder. This process, known as metamorphosis, is a stunning example of nature's resilience and adaptability.The Butterfly LifecycleA butterfly's life begins as a tiny egg, often laid on the underside of a leaf or stem of a specific host plant. Once hatched, the emerging caterpillar embarks on a voracious journey, consuming vast quantities of plant matter to fuel its rapid growth.As the caterpillar grows, it periodically sheds its skin through a process called molting, allowing for its ever-expanding body. After several rounds of molting, the caterpillar enters the pupal stage, where it undergoes a remarkable transformation within a protective chrysalis.Inside this seemingly lifeless casing, the caterpillar's body breaks down into a soupy mixture before reorganizing into theintricate structures of a butterfly. This miraculous process, orchestrated by a complex interplay of hormones and genetic programming, culminates in the emergence of a fully formed adult butterfly.With its new wings unfurled and its body hardened, the butterfly takes its first tentative flight, embarking on a new phase of its life. Its primary objective now is to find a mate and reproduce, ensuring the continuation of its species.The Butterfly's Role in NatureButterflies play a vital role in maintaining the delicate balance of ecosystems. As pollinators, they contribute significantly to the reproduction of numerous plant species, transferring pollen from one flower to another as they flit from bloom to bloom in search of nectar.Their pollination services are essential for the survival of many wildflowers, fruits, and vegetables, making them invaluable allies in sustaining biodiversity and supporting agriculture. Additionally, butterflies serve as food sources for various predators, such as birds, lizards, and spiders, further underscoring their importance in the intricate web of life.Threats and ConservationDespite their beauty and ecological significance, butterflies face numerous threats, primarily driven by human activities. Habitat loss due to urbanization, deforestation, and agricultural expansion has severely impacted many butterfly species, depriving them of the specific plants and environments they rely upon.Pesticide use in agriculture and gardens can also have devastating effects, poisoning both adult butterflies and their caterpillar stages. Climate change, too, poses a significant challenge, disrupting the delicate synchronization between butterflies and the plants they depend on for sustenance and breeding.In response to these threats, conservation efforts have gained momentum worldwide. Organizations and individuals alike are working tirelessly to protect butterfly habitats, establish butterfly gardens, and raise awareness about the importance of these winged wonders.Through education and sustainable practices, we can ensure that future generations have the opportunity to witness the breathtaking spectacle of butterflies in flight, their vibrant colors dancing across fields and gardens.In ConclusionButterflies are not merely beautiful creatures; they are living emblems of nature's resilience, adaptation, and interconnectedness. By studying their intricate physiology, remarkable lifecycle, and vital role within ecosystems, we gain a deeper appreciation for the complexity and fragility of the natural world.As students of nature, it is our responsibility to understand and protect these extraordinary insects, for in doing so, we safeguard the delicate balance that sustains all life on our planet. Let us embrace the wondrous world of butterflies, marveling at their beauty while working tirelessly to ensure their continued presence in the tapestry of life.篇2The Marvelous Life of ButterfliesButterflies are one of the most mesmerizing creatures on our planet. With their delicate wings adorned in vibrant colors and intricate patterns, they seem to float through the air like ethereal beings from another world. As a student fascinated by nature, I have spent countless hours observing and researching these captivating insects, and I am continually amazed by their incredible physical features and fascinating lifestyles.The most striking aspect of a butterfly's appearance is undoubtedly its wings. These gossamer appendages are not only visually stunning but also serve as the butterfly's primary means of locomotion and temperature regulation. The wings are composed of two layers of chitin, a tough, semitransparent material that is both lightweight and flexible. Between these layers lies a network of veins that provide structural support and channels for the circulation of fluids.What makes a butterfly's wings truly remarkable, however, are the millions of tiny scales that cover their surface. These scales, which are essentially flattened hair-like structures, are responsible for the incredible diversity of colors and patterns we see on butterfly wings. Each scale is a masterpiece of nature's artistry, reflecting and refracting light in a way that creates a kaleidoscope of hues. From the brilliant blues and oranges of the Morpho butterflies to the intricate eye-spots of the Buckeye, the sheer variety of wing patterns is simply breathtaking.Butterflies' physical features extend far beyond their wings, however. Their bodies are divided into three main segments: the head, thorax, and abdomen. The head houses a pair of large compound eyes, which are composed of thousands of individual lenses, allowing the butterfly to have a nearly 360-degree field ofvision. This keen eyesight is crucial for spotting potential mates, locating food sources, and avoiding predators.The thorax is the powerhouse of the butterfly's body, housing the muscles that control its wings and legs. The legs, which are relatively short and hairy, serve primarily for grasping onto surfaces and positioning the body for feeding or mating. It is the abdomen, however, that contains the butterfly's digestive and reproductive organs, as well as the spiracles through which it breathes.While the physical features of butterflies are undoubtedly captivating, their lifestyles are equally fascinating. Most species undergo a remarkable transformation known as metamorphosis, which involves four distinct stages: egg, larva (caterpillar), pupa, and adult.The journey begins when a female butterfly lays her eggs on the leaves of a host plant, carefully selecting a species that will provide nourishment for her offspring. After a few days or weeks, depending on the species and environmental conditions, the eggs hatch into tiny caterpillars.These voracious larvae spend the majority of their lives eating, growing, and molting (shedding their exoskeletons) as they increase in size. Some caterpillars, like the iconic Monarch,are brightly colored as a warning to predators of their toxicity, while others rely on camouflage to blend in with their surroundings.Once the caterpillar has reached its final larval stage, it attaches itself to a suitable surface and undergoes a remarkable transformation. Its body contracts and hardens into a protective casing called a chrysalis or pupa. Inside this seemingly lifeless shell, the caterpillar's body undergoes a complete metamorphosis, with its cells reorganizing and forming the wings, legs, and other structures of an adult butterfly.After several weeks or months, depending on the species and environmental conditions, the adult butterfly emerges from the chrysalis, its wings wet and crumpled. It must then hang upside down and pump fluid into its wings, allowing them to expand and dry into their full, glorious form.The adult stage of a butterfly's life is relatively short, lasting anywhere from a few days to several months. During this time, the primary focus is on mating and reproduction. Butterflies employ a variety of strategies to attract mates, from releasing pheromones to performing intricate courtship dances.Once mating has occurred, the female butterfly must locate suitable host plants on which to lay her eggs, perpetuating thecycle of life. Some species, like the Monarch, undertake incredible migrations, traveling thousands of miles to reach their breeding grounds.Throughout their lives, butterflies play a crucial role in the ecosystem as pollinators. As they flit from flower to flower, sipping nectar with their long, coiled proboscis (tongue-like mouthpart), they inadvertently transfer pollen, facilitating the reproduction of many plant species.Sadly, despite their beauty and ecological importance, many butterfly species are facing significant threats from human activities. Habitat loss, pesticide use, and climate change are all contributing to declining populations worldwide. As students and stewards of the natural world, it is our responsibility to learn about and protect these extraordinary creatures, ensuring that future generations can continue to marvel at the majesty of butterflies.In conclusion, butterflies are truly remarkable insects, possessing a unique blend of physical characteristics and lifestyle adaptations that have captivated humankind for centuries. From their delicate yet intricate wings to their incredible metamorphosis, these creatures are a testament to the wonders of nature. By studying and appreciating butterflies, we not onlygain a deeper understanding of the natural world but also a renewed sense of awe and respect for the diversity of life on our planet.篇3The Wondrous World of Butterflies: Examining their Intricate Anatomy and Fascinating LifestylesButterflies are undoubtedly one of the most beautiful and captivating creatures on our planet. As a student fascinated by the natural world, I have spent countless hours observing and studying these delicate insects, marveling at their intricate anatomy and mesmerizing life cycles. In this essay, I will delve into the remarkable physical characteristics and lifestyles of butterflies, offering insights that will hopefully inspire a greater appreciation for these winged wonders.Physical Characteristics:Wings: The most striking feature of butterflies is, without a doubt, their wings. These intricate structures are not only visually stunning but also serve as a testament to nature's artistry. Butterfly wings are covered in tiny scales, which are actually flattened hair-like structures called lepidopteran scales. These scales are responsible for the stunning array of colors andpatterns that adorn their wings, ranging from the vibrant hues of the Monarch to the intricate designs of the Swallowtail.The wing patterns serve various purposes, including camouflage, mimicry, and even communication. For instance, some butterflies have evolved to resemble leaves or tree bark, providing them with effective camouflage from predators. Others have developed wing patterns that mimic the appearance of more dangerous species, deterring potential threats through a process known as Batesian mimicry.Proboscis: Butterflies possess a long, coiled structure called a proboscis, which serves as their feeding tube. This remarkable organ is composed of two separate halves that join together to form a straw-like apparatus. When not in use, the proboscis remains coiled up underneath the butterfly's head. However, when it's time to feed, the proboscis unfurls and extends, allowing the butterfly to sip nectar from flowers or other liquid sources.Body Structure: The butterfly's body is divided into three main segments: the head, thorax, and abdomen. The head houses the compound eyes, which are composed of thousands of individual lenses, providing the butterfly with exceptional visual acuity. The thorax serves as the powerhouse, containingthe muscles that control the wings and legs. Finally, the abdomen houses the digestive and reproductive systems.Antennae: Butterflies possess a pair of slender antennae on their heads, which serve as sensory organs. These antennae are covered in tiny hairs that detect various chemical cues, aiding the butterfly in locating food sources, potential mates, and even helping them navigate their environment.Lifestyles and Behavior:Life Cycle: Butterflies undergo a remarkable transformation known as metamorphosis, which involves four distinct stages: egg, larva (caterpillar), pupa (chrysalis), and adult. This process is nothing short of miraculous, as the caterpillar undergoes a complete reorganization of its body structure within the chrysalis, emerging as a stunningly beautiful winged adult.Feeding Habits: As adults, butterflies primarily feed on nectar from flowers, using their proboscis to sip the sweet liquid. However, some species also obtain nutrients from other sources, such as rotting fruit, tree sap, or even dissolved minerals in puddles or streams. Their feeding habits play a crucial role in pollination, as they inadvertently transfer pollen from one flower to another while collecting nectar.Migration: Some butterfly species, such as the iconic Monarch, embark on remarkable migrations that span thousands of miles. These journeys are driven by the need to locate suitable breeding grounds or escape harsh winter conditions. The Monarch's migration from the United States and Canada to overwintering sites in Mexico is a truly awe-inspiring phenomenon that has captivated scientists and nature enthusiasts alike.Mating and Reproduction: Butterflies engage in intricate courtship rituals to attract mates, often involving elaborate wing displays and specific pheromone signals. Once mated, the female will lay her eggs on specific host plants, which serve as food sources for the emerging caterpillars. The caterpillars then undergo a series of molts, shedding their skin as they grow, before finally forming a chrysalis and completing the metamorphic transformation into an adult butterfly.Predators and Defense Mechanisms: Despite their delicate appearance, butterflies have evolved various defense mechanisms to protect themselves from predators. Some species employ camouflage or mimicry, as mentioned earlier, while others rely on chemical defenses. For instance, certain butterflyspecies sequester toxins from the plants they feed on as caterpillars, making them unpalatable to predators as adults.Conclusion:Butterflies are truly remarkable creatures that inspire awe and wonder in all who observe them. Their intricate anatomy, with features like the vibrant wings, coiled proboscis, and intricate body structure, is a testament to the incredible diversity and complexity of life on our planet. Moreover, their fascinating lifestyles, encompassing metamorphosis, migration, and intricate reproductive behaviors, serve as a reminder of the resilience and adaptability of nature.As a student captivated by the natural world, studying butterflies has been an enriching and humbling experience. It has deepened my appreciation for the intricate web of life that surrounds us and reinforced the importance of preserving and protecting these delicate creatures and their habitats. Butterflies are not only aesthetically pleasing but also play crucial roles in various ecosystems, acting as pollinators and contributing to the overall balance of the natural world.I encourage everyone to take the time to observe and appreciate these winged wonders, whether in their natural habitats or in dedicated butterfly gardens and conservatories. Byfostering a deeper understanding and appreciation for butterflies, we can cultivate a greater respect for all forms of life and inspire efforts to safeguard the delicate ecosystems upon which we all depend.。

表面技术第52卷第2期金属锌与PTFE改性建筑陶瓷表面的润湿性能研究萧礼标1，姚蔚2，刘一军1，汪庆刚1，李凯凯2，吴洋1，陆龙生2（1.蒙娜丽莎集团股份有限公司，广东 佛山 528211；2.华南理工大学 机械与汽车工程学院，广州 510641）摘要：目的结合金属锌和聚四氟乙烯（PTFE）改性技术，制备具有微纳复合结构表面的超疏水、防污染、自清洁建筑陶瓷。

方法基于现有工业陶瓷生产方法，在陶瓷釉料中掺入质量分数为60%的金属锌粉，通过高温烧结在陶瓷表面构建微纳复合结构，随后在其表面喷涂PTFE涂料进行低表面能处理，从而制得超疏水性建筑陶瓷。

利用扫描电镜和光学轮廓仪，观察陶瓷表面微纳形貌。

通过X射线能谱仪，对陶瓷表面的化学元素组成进行分析。

使用光学测量系统，测量水滴在陶瓷表面的静态接触角和滚动角。

根据测试结果分析5种烧结温度对陶瓷表面微纳结构和润湿性能的影响。

结果随着烧结温度的升高，陶瓷表面的均方根粗糙度（S q）先增大后减小，对应的疏水性能先增强后减弱。

在1 000 ℃（保温10 min）烧结温度下，S q达到最大值，为(17.52±2.54) μm，表现出最优的超疏水性能，其静态接触角和滚动角分别为165.6°和8.2°，并且该表面展示出良好的防污能力和耐磨性。

结论液滴与陶瓷表面接触时，由金属锌粉烧结形成的微纳复合结构和低表面能的PTFE起耦合协同作用，陶瓷表面与液滴形成固-液-气三相复合接触的Cassie-Baxter状态，即阻隔的空气垫阻碍液体浸入微纳复合结构之中。

随着陶瓷表面粗糙度的增加，气-液接触面积增加，从而使得疏水性能得到提升。

关键词：金属锌；PTFE；建筑陶瓷；烧结温度；微纳复合结构；超疏水表面中图分类号：TU523; TB34 文献标识码：A 文章编号：1001-3660(2023)02-0360-09DOI：10.16490/ki.issn.1001-3660.2023.02.034Surface Wettability of Building Ceramics Modifiedby Zinc Metal and PTFEXIAO Li-biao1, YAO Wei2, LIU Yi-jun1, WANG Qing-gang1, LI Kai-kai2, WU Yang1, LU Long-sheng2(1. Monalisa Group Co., Ltd., Guangdong Foshan 528211, China; 2. School of Mechanical &Automotive Engineering, South China University of Technology, Guangzhou 510641, China) ABSTRACT: The pollution of building ceramics has grown to be a significant issue in people’s lives. Interestingly,收稿日期：2021–11–09；修订日期：2022–07–27Received：2021-11-09；Revised：2022-07-27基金项目：广东省自然科学基金面上项目（2019A1515011530）Fund：Natural Science Foundation of Guangdong Province (2019A1515011530)作者简介：萧礼标（1975—），男，博士，高级工程师，主要研究方向为建筑陶瓷材料。