Effect of deposition rate on the characteristics

Coating thickness effects on diamond coated cutting toolsF. Qin, Y.K. Chou,D. Nolen and R.G. ThompsonAvailable online 12 June 2009金刚石涂层刀具的涂层厚度的影响作者：F. Qin, Y.K. Chou,D. Nolen and R.G. Thompson发表日期：2009Abstract：Chemical vapor deposition (CVD)-grown diamond films have found applications as a hard coating for cutting tools. Even though the use of conventional diamond coatings seemsto be accepted in the cutting tool industry, selections of proper coating thickness for differentmachining operations have not been often studied. Coating thickness affects the characteristics of diamond coated cutting tools in different perspectives that may mutuallyimpact the tool performance in machining in a complex way.In this study, coating thickness effects on the deposition residual stresses, particularlyaround a cutting edge, and on coating failure modes were numerically investigated. 化学气相沉积法（CVD），金刚石薄膜的发现，作为涂层刀具的应用。

Electrochemical deposition (ECD), a versatile and widely employed surface modification technique, offers unparalleled precision and control in the creation of functional coatings, thin films, and nanostructured materials. This method involves the controlled reduction or oxidation of ions at an electrode surface under the influence of an applied electric field, resulting in the formation of a deposit with desired properties. To achieve high-quality and high-standard ECD processes, it is crucial to consider multiple factors, including the selection of appropriate electrolyte systems, electrode design, process parameters, and post-deposition treatments. This comprehensive analysis delves into these aspects, highlighting their significance and interplay in ensuring the successful execution of electrochemical deposition.1. **Electrolyte Systems: The Foundation of Electrochemical Deposition**The choice of electrolyte system plays a pivotal role in determining the quality and standard of the deposited material. An ideal electrolyte should:a. **Contain the desired metal ions**: The electrolyte must contain soluble salts or complexes of the metal to be deposited. The chemical stability, solubility, and redox potential of these ions directly influence the deposition rate, morphology, and composition of the film.b. **Provide suitable supporting electrolytes**: Supporting electrolytes, such as inorganic salts or organic additives, enhance ionic conductivity, stabilize the double layer, and minimize side reactions. They also influence the nucleation and growth kinetics of the deposit, affecting its microstructure and adhesion.c. **Include functional additives**: To tailor the properties of the deposited material, various functional additives can be incorporated into the electrolyte. These may include surfactants for modifying surface energy and controlling particle size, complexing agents for adjusting ion speciation, or inhibitors for suppressing unwanted reactions or impurity incorporation.2. **Electrode Design: The Interface of Electrochemistry and Deposition**The design and preparation of the substrate electrode significantly impactthe quality and standard of the deposited film. Key considerations include:a. **Substrate material**: The substrate material should possess adequate electrical conductivity, chemical compatibility with the electrolyte, and mechanical stability during the deposition process. Moreover, its surface chemistry and roughness can influence nucleation and adhesion of the deposited layer.b. **Surface pre-treatment**: Prior to deposition, the substrate surface may require cleaning, polishing, or activation treatments to remove contaminants, create a defined surface topography, or induce specific surface chemistries that promote nucleation and adhesion.c. **Electrode geometry**: The electrode geometry, including shape, size, and arrangement, can affect mass transport, current distribution, and the development of local electric fields, which in turn influence deposition uniformity, thickness control, and defect formation.3. **Process Parameters: The Fine-Tuning Elements**Optimizing process parameters is crucial for achieving high-quality and high-standard electrochemical deposition. Key parameters include:a. **Applied voltage or current**: The magnitude and mode (direct current, pulsed current, alternating current) of the applied electrical field govern the kinetics of ion reduction/oxidation, deposition rate, and energy input into the system. Careful control is essential for achieving desired film thickness, composition, and microstructure.b. **Temperature**: Temperature influences electrolyte conductivity, reaction kinetics, and mass transport. It can be used to modulate deposition rate, phase formation, and stress development in the deposited film.c. **Deposition time**: The duration of the deposition process determines the overall thickness of the film and can influence the evolution of microstructure and properties. Balancing deposition time with other parameters ensures efficient use of resources while maintaining desired film characteristics.4. **Post-Deposition Treatments: Enhancing and Preserving Deposit Quality**Post-deposition treatments are often employed to further refine the properties of the electrochemically deposited material or to ensure its long-term stability. Some common treatments include:a. **Annealing**: Thermal annealing can be used to homogenize the microstructure, relieve residual stresses, improve crystallinity, or induce phase transformations, thereby enhancing the mechanical, electrical, or optical properties of the deposited film.b. **Chemical or electrochemical passivation**: Surface passivation treatments can be applied to increase corrosion resistance, reduce surface roughness, or modify surface chemistry for improved adhesion or functionality in subsequent processing steps.c. **Mechanical or chemical polishing**: Polishing techniques can be employed to achieve a desired surface finish, remove defects, or control the thickness of the deposited layer with high precision.In conclusion, achieving high-quality and high-standard electrochemical deposition requires a holistic approach that encompasses careful selection of electrolyte systems, meticulous design of electrode substrates, optimization of process parameters, and strategic implementation of post-deposition treatments. Each of these aspects is interconnected and contributes uniquely to the overall performance and reliability of the deposited material. By systematically considering and fine-tuning these factors, researchers and engineers can harness the full potential of electrochemical deposition for the synthesis of advanced functional coatings, thin films, and nanostructured materials with tailored properties and exceptional performance.。

新型抗阿尔茨海默病药物甘露寡糖二酸一、本文概述Overview of this article随着全球人口老龄化趋势的加剧，阿尔茨海默病（Alzheimer's Disease，AD）作为一种慢性神经退行性疾病，已经成为影响老年人生活质量的主要健康问题之一。

其临床表现主要为记忆障碍、失语、失用、失认、视空间技能损害、执行功能障碍以及人格和行为改变等，严重影响了患者的日常生活和社会功能。

目前，尽管已经有一些药物被批准用于治疗阿尔茨海默病，但这些药物在缓解症状、延缓疾病进程方面仍然存在一定的局限性。

因此，研发新型、有效的抗阿尔茨海默病药物成为了当前医学研究的热点和难点。

With the intensification of the global aging trend, Alzheimer's Disease (AD), as a chronic neurodegenerative disease, has become one of the main health problems affecting the quality of life of the elderly. Its clinical manifestations mainly include memory impairment, aphasia, loss of use, loss of recognition, impairment of visual and spatial skills, executive dysfunction, and personality and behavioral changes,which seriously affect the patient's daily life and social function. At present, although some drugs have been approved for the treatment of Alzheimer's disease, these drugs still have certain limitations in alleviating symptoms and delaying disease progression. Therefore, the development of new and effective anti Alzheimer's disease drugs has become a hot and difficult topic in current medical research.近年来，甘露寡糖二酸（Mannosylglycerate，MG）作为一种具有独特生物活性的天然产物，其在抗阿尔茨海默病方面的潜在作用逐渐受到了关注。

第53卷第1期表面技术2024年1月SURFACE TECHNOLOGY·15·激光增材制造钛合金微观组织和力学性能研究进展竺俊杰1，王优强1,2*，倪陈兵1,2，王雪兆1，刘德建1，房玉鑫1，李梦杰1（1.青岛理工大学，山东 青岛 266520；2.工业流体节能与污染控制教育部重点实验室，山东 青岛 266520）摘要：激光选区熔化（SLM）技术与激光熔化沉积（LMD）技术在航空航天、生物医疗等领域的应用具有巨大潜力，但由于成形的Ti6Al4V合金构件存在较差的表面质量、较大的残余应力以及内部孔洞等问题，影响了构件的力学性能，从而制约了其大规模的应用。

针对这一现状，首先概述了激光选区熔化技术与激光熔化沉积技术的制造原理，比较了2种增材制造技术的成形参数及其特点，并分析了2种不同成形技术的自身优势以及适用场合。

其次，从2种增材制造技术成形钛合金的工艺参数入手，综述了激光功率、扫描速度、激光扫描间距、铺粉厚度、粉床温度等参数对SLM工艺成形钛合金的影响，以及激光功率、扫描速度、送粉速率等参数对LMD工艺成形钛合金的影响。

发现成形工艺参数直接影响了粉末熔化程度、熔合质量和成形显微结构，从而影响成形件的组织与力学性能。

此外，综述了不同的扫描策略对两种增材制造技术成形钛合金的表面质量与力学性能的影响，可以发现在不同扫描策略下同一试样表面的不同区域表面质量、残余应力以及抗拉强度存在较大差异，同一扫描策略下试样的不同表面之间也存在各向异性。

最后，探讨了不同热处理工艺对钛合金微观组织和力学性能的影响，通过合适的热处理能够降低成形构件应力，并调控组织相变和性能。

关键词：激光选区熔化；激光熔化沉积；钛合金；微观组织；力学性能；热处理中图分类号：TG146.23 文献标志码：A 文章编号：1001-3660(2024)01-0015-18DOI：10.16490/ki.issn.1001-3660.2024.01.002Research Progress on Microstructure and Mechanical Propertiesof Titanium Alloy by Laser Additive ManufacturingZHU Junjie1, WANG Youqiang1,2*, NI Chenbing1,2, WANG Xuezhao1,LIU Dejian1, FANG Yuxin1, LI Mengjie1(1. Qingdao University of Technology, Shandong Qingdao 266520, China;2. Key Lab of Industrial Fluid Energy Conservation and Pollution Control, Shandong Qingdao 266520, China)ABSTRACT: Selective laser melting (SLM) technology and laser melting deposition (LMD) technology are becoming收稿日期：2022-11-30；修订日期：2023-06-15Received：2022-11-30；Revised：2023-06-15基金项目：山东省自然科学基金（ZR2021ME063）Fund：The Natural Science Foundation of Shandong Province (ZR2021ME063)引文格式：竺俊杰, 王优强, 倪陈兵, 等. 激光增材制造钛合金微观组织和力学性能研究进展[J]. 表面技术, 2024, 53(1): 15-32.ZHU Junjie, WANG Youqiang, NI Chenbing, et al. Research Progress on Microstructure and Mechanical Properties of Titanium Alloy by Laser Additive Manufacturing[J]. Surface Technology, 2024, 53(1): 15-32.*通信作者（Corresponding author）·16·表面技术 2024年1月increasingly close to the properties of manufactured titanium alloys and forgings, which have great potential for applications in aerospace, biomedical and other fields. However, the poor surface quality, large residual stresses and the presence of internal holes in the formed Ti6Al4V alloy components affect the mechanical properties of the components, thus limiting their large-scale application. To address this situation, this work firstly outlined the manufacturing principles of selective laser melting and laser melting deposition, compared the forming parameters and characteristics of the two additive manufacturing technologies, and analyzed the advantages and applications of the two different forming technologies. Since the selective laser melting technique could adjust the thickness of the laying powder, a smaller laser spot diameter was chosen to improve the surface quality and dimensional accuracy of the formed components. The laser melting and deposition technology adopted coaxial powder feeding for faster processing and was more suitable for manufacturing medium to large metal parts.Secondly, the effects of laser power, scanning speed, laser scanning pitch, powder thickness and powder bed temperature on the forming of titanium alloys by SLM process and the effects of laser power, scanning speed and powder feeding rate on the forming of titanium alloys by LMD process were reviewed from the forming process parameters of the two additive manufacturing technologies, revealing the intrinsic effects of forming parameters, microstructure and mechanical properties in the additive manufacturing process. The direct parameters of the forming process were found to affect the degree of powder melting, fusion quality and forming microstructure, thus affecting the organization and mechanical properties of the formed parts. The effect of laser power and scanning speed on the forming process was more obvious than other factors, and there was a greater correlation between them, and a combination of lower laser power and higher scanning speed could be adopted to obtain specimens with higher microhardness. In addition, the effects of different scanning strategies on the surface quality and mechanical properties of titanium alloys formed by the two additive manufacturing techniques were reviewed, and it was found that the surface quality, residual stress and tensile strength of different regions of the same specimen surface under different scanning strategies differed significantly, and anisotropy existed between different surfaces of the specimen under the same scanning strategy. Finally, the effects of different heat treatment processes on the microstructure and mechanical properties of titanium alloys were investigated, and suitable heat treatments could reduce the stresses and regulate the phase changes and properties of formed components. Two heat treatments, annealing and solution aging, can be combined to balance the strength and plasticity of the component. To summarize the research development of these two additive manufacturing technologies, it is necessary to accelerate the establishment of a complete system of methods under the forming process and forming environment, and to promote the research on the mechanism of microstructure evolution and macro mechanical properties influence.KEY WORDS: selective laser melting; laser melting deposition; titanium alloy; microstructure; mechanical properties; heat treatment由于钛合金有着比强度较高、生物相容性较好以及耐腐蚀性能好的优势，因此在全球范围内广泛应用于生物医疗与航空领域[1-2]。