Zinc–nickel alloy coatings electrodeposited from a chloride bath using direct and pulse current

chromeplate：镀铬Bright chrome plating：镀亮铬white zinc-plating ：蓝白锌电镀color-plated zinc:彩锌Electrophoresis:电泳powder coated：烤漆1.电珍珠铬工艺常用语(Commonly used terminology in process for pearl chrome plating)硫酸清洗sulfuric acid clean超声波除蜡ultrasonic clean除油degreasing电解除油electro clean酸浸acid dip预镀碱铜alkali copper焦铜pyrophosphate copper酸铜acid copper半光叻semi-bright nickel氯化叻nickel chloride珍珠叻pearl nickel电铬chromium plated热水洗hot water rinsing烘干baking2. 电光铬工艺常用语(Commonly used terminology in process for bright chrome plating)三氯乙烯清洗trichloroethylene clean上挂具racking除蜡水洗ultrasonic clean电解缸electro clean酸水acid dip预红铜电镀copper strike电红铜copper酸水acid焦铜pyrophosphate copper酸铜acid copper半光叻semi-bright nickel氯化叻nickel chloride打底叻primer nickel镍色bright nickel电铬chromium plated烘干baking3.静电喷涂工艺常用语(Commonly used terminology in process for electrostatic coating)合格件上挂racking加热脱脂hot degreasing水洗rinsing酸洗acid dip中和neutralization表调surface conditioning磷化phosphating水洗二次rinsing x2烘干baking检查inspection上挂racking除尘dedusting喷涂spray painting固化curing下挂taking down包装packaging4.静电喷粉工艺常用语(Commonly used terminology in process for electrostatic powder)合格件上挂racking加热脱脂hot degreasing水洗rinsing中和neutralization表调surface conditioning钝化passivating水洗二次rinsing x2烘干baking检查inspection上挂racking除尘dedusting喷涂spray powder固化curing下挂taking down包装packaging补充词汇(Additional words)闪镀flash/falsh plate光亮电镀bright plating合金电镀alloy plating多层电镀multilayer plating金属喷镀metal spraying刷镀brush plating挂镀rack plating脉冲电镀pulse plating真空镀vacuum deposition热浸镀hot dipping离子镀ion plating滚镀barrel plating装饰性镀铬electroplating adom-chrome镀硬铬electroplating hard chrome钢铁发蓝/钢铁化学氧化blueing (chemical oxide)退镀stripping预镀strike化学抛光chemical polishing浸亮bright dipping活化activation机械抛光mechanical polishing粗化roughtening机械/化学粗化machine/chemistry coarsening敏化处理sensitizationABS塑料电镀plastic plating processpH计pH meter 测定溶液pH值的仪器。

Designation:F1941M–05METRICStandard Specification forElectrodeposited Coatings on Threaded Fasteners[Metric]1 This standard is issued under thefixed designation F1941M;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis specification covers the coating of steel metric screw threaded fasteners by electrodeposition. The properties of the coatings shall conform to the ASTM standards for the individualfinishes listed. Coating thickness values are based on the tolerances for M series metric threads having the following tolerance positions:6g and4g6g for external threads,and6H for internal threads.The coating must not cause the basic thread size to be transgressed by either the internal or external threads.The method of designating coated threads shall comply with ASME B1.13M.With normal methods for depositing metallic coatings from aqueous solutions,there is a risk of delayed failure due to hydrogen embrittlement for case hardened fasteners and fasteners having a hardness40HRC or above.Although this risk can be managed by selecting raw materials suitable for the application of electrodeposited coatings and by using modern methods of surface treatment and post heat-treatment(baking),the risk of hydrogen embrittlement cannot be completely eliminated. Therefore,the application of a metallic coating by electrodeposition is not recommended for such fasteners.1.Scope1.1This specification covers application,performance and dimensional requirements for electrodeposited coatings on threaded fasteners with metric screw threads.It specifies coating thickness,supplementary chromatefinishes,corrosion resistance,precautions for managing the risk of hydrogen embrittlement and hydrogen embrittlement relief for high-strength and surface-hardened fasteners.It also highlights the differences between barrel and rack plating and makes recom-mendations as to the applicability of each process.1.2The following precautionary statement pertains to the test method portion only,Section9,of this specification:This standard does not purport to address all of the safety concerns, if any,associated with its use.It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limita-tions prior to use.2.Referenced Documents2.1ASTM Standards:2B117Practice for Operating Salt Spray(Fog)Apparatus B487Test Method for Measurement of Metal and Oxide Coating Thickness by Miocroscopical Examination of a Cross SectionB499Test Method for Measurement of Coating Thickness by the Magnetic Method:Nonmagnetic Coatings on Mag-netic Basis MetalsB504Test Method for Measurement of Thickness of Me-tallic Coatings by the Coulometric MethodB567Test Method for Measurement of Coating Thickness by the Beta Backscatter MethodB568Test Method for Measurement of Coating Thickness by X-Ray SpectrometryB659Guide for Measuring Thickness of Metallic and Inorganic Coatings1This specification is under the jurisdiction of ASTM Committee F16onFasteners and is the direct responsibility of Subcommittee F16.03on Coatings on Fasteners.Current edition approved May1,2005.Published May2005.Originally approved st previous edition approved in2000as F1941M–00.2For referenced ASTM standards,visit the ASTM website,,or contact ASTM Customer Service at service@.For Annual Book of ASTM Standards volume information,refer to the standard’s Document Summary page on the ASTM website.1Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.E 376Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-Current (Electromagnetic)Exami-nation MethodsF 606Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners,Washers,and RivetsF 1470Guide for Fastener Sampling for Specified Mechani-cal Properties and Performance InspectionF 1624Test Method for Measurement of Hydrogen Em-brittlement Threshold in Steel by the Incremental Step Loading TechniqueF 1940Test Method for Process Control Verification to Prevent Hydrogen Embrittlement in Plated or Coated Fasteners2.2ASME Standard:3B1.13M Metric Screw Threads -M Profile 2.3National Aerospace Standard (AIA):4NASM-1312-5Fast Test Method -Method 5:Stress Dura-bility2.4IFI Standard:5IFI-142Hydrogen Embrittlement Risk Management 3.Terminology 3.1Definitions:3.1.1local thickness —mean of the thickness measurements,of which a specified number is made within a reference area.3.1.2minimum local thickness —lowest local thickness value on the significant surface of a single article.3.1.3reference area —area within which a specified number of single measurements are required to be made.3.1.4significant surface —significant surfaces are areas where the minimum thickness to be met shall be designated on the applicable drawing or by the provision of a suitably marked sample.However,if not designated,significant surfaces shall be defined as those normally visible,directly or by reflection,which are essential to the appearance or serviceability of the fastener when assembled in normal position,or which can be the source of corrosion products that deface visible surfaces on the assembled fastener.Figs.1and 2illustrate significant surfaces on standard externally threaded and internally threaded fasteners.4.Classification4.1Coating Material —The coating material shall be se-lected and designated in accordance with Table 1.4.2Coating Thickness —The coating thickness shall be selected and designated in accordance with Table 2.4.3Chromate Finish —The chromate finish shall be selected and designated in accordance with Table 3.5.Ordering Information for Electroplating5.1When ordering threaded fasteners to be coated by electrodeposition in accordance with this specification,the following information shall be supplied to the electroplater:5.1.1The desired coating,coating thickness and the chro-mate finish,or the classification codes as specified in Tables 1-3.(For example,Fe/Zn 5C denotes yellow zinc plated with a minimum thickness of 5µm on significant surfaces.)5.1.2The identification of significant surfaces (optional).5.1.3The requirement,if any,for stress relief before elec-troplating,in which case the stress-relief conditions must be specified.5.1.4The requirements,if any,for hydrogen embrittlement relief by heat treatment (baking)stating the tensile strength or surface hardness of the fasteners and/or baking time and temperature.N OTE 1—Fasteners with a specified maximum hardness of 34HRC and below have a very low susceptibility to hydrogen embrittlement and do not require baking.3Available from American Society of Mechanical Engineers (ASME),345E.47th Street,New York,NY 10017.4Available from Standardization Documents Order Desk,DODSSP,Bldg.4,Section D,700Robbins Ave.,Philadelphia,PA 19111-5098.5Available from Industrial Fasteners Institute (IFI),1717East 9th Street,Suite 1105,Cleveland,OH44114–2879.N OTE 1—Black dot (•)indicates test surface.FIG.1Significant surfaces on Externally ThreadedFastenersN OTE 1—Black dot (•)indicates test surface.FIG.2Significant surfaces on Internally Threaded FastenersTABLE 1Designation of Common Coating MaterialsCoating DesignationCoating Type Fe/Zn Zinc Fe/Cd Cadmium Fe/Zn-Co Zinc Cobalt Alloy Fe/Zn-Ni Zinc Nickel Alloy Fe/Zn-FeZinc Iron AlloyTABLE 2Designation of Coating ThicknessN OTE 1—The conversion factor from microns to inch is 3.94310–5(for example,5µm =0.0002in.).Thickness DesignationMinimum Thickness µm3355881212F 1941M –055.1.5The requirements,if any,for the type of electroplating process (barrel-plating or rack-plating).See Section 10and Appendix X1.5.1.6The designation of coated thread class shall comply with ASME B1.13M.6.Requirements6.1Coating Requirements —The electrodeposited coating as ordered shall cover all surfaces and shall meet the following requirements:6.1.1The coating metal deposit shall be bright or semi-bright unless otherwise specified by the purchaser,smooth,fine grained,adherent and uniform in appearance.6.1.2The coating shall be free of blisters,pits,nodules,roughness,cracks,unplated areas,and other defects that will affect the function of the coating.6.1.3The coating shall not be stained,discolored or exhibit any evidence of white or red corrosion products.6.1.3.1Slight discoloration that results from baking,drying,or electrode contact during rack-plating,or all of these,as well as slight staining that results from rinsing shall not be cause for rejection.6.2Corrosion Resistance —Coated fasteners,when tested by continuous exposure to neutral salt spray in accordance with 9.3,shall show neither corrosion products of coatings (white corrosion)nor basis metal corrosion products (red rust)at the end of the test period.The appearance of corrosion products visible to the unaided eye at normal reading distance shall be cause for rejection,except when present at the edges of the tested fasteners.Refer to Annex A1for neutral salt spray performance requirements for zinc,zinc alloy and cadmium coatings.6.3Thickness —The coating thickness shall comply with requirements of Table 2when measured in accordance with 9.1.6.3.1Restrictions on Coating Thickness —This specification imposes minimum local thickness requirements at significant surfaces in accordance with Table 2.Thick or thin local thickness in a location other than a significant surface shall not be a cause for rejection.However the following restrictions apply:6.3.1.1Minimum coating thickness at low current density areas,such as the center of a bolt or recesses,must be sufficient to provide for adequate chromate adhesion.6.3.1.2External Threads —Maximum coating thickness at high current density threaded tips must provide for basic (tolerance position h )GO thread gauge acceptance.Therefore,the thread after coating is subject to acceptance using a class 6hGO gauge for plated 6g class external threads and 4h6h GO gauge for plated 4g6g class external threads respectively.6.3.1.3Internal Threads —Maximum coating thickness of internal threads must provide for basic (tolerance position H )Go thread gauge acceptance.Therefore,the thread after coating is subject to acceptance using a class 6H GO gauge for 6H class internal threads.6.3.1.4Surfaces such as threads,holes,deep recesses,bases of angles,and similar areas on which the specified thickness of deposit cannot readily be controlled,are exempted from minimum thickness requirements unless they are specially designated as not being exempted.When such areas are subject to minimum thickness requirements,the purchaser and the manufacturer shall recognize the necessity for either thicker deposits on other areas or special racking.6.3.2Applicability to M Series Threads :6.3.2.1The applicability of the required coating to M series metric threads is limited by the basic deviation of the threads,and hence limited by the pitch diameter,allowance,and tolerance positions.Refer to Appendix X3as a guideline for the tolerances of the various thread sizes and classes and the coating thickness they will accommodate.6.3.2.2Because of the inherent variability in coating thick-ness by the barrel-plating process,the application of a mini-mum coating thickness of 12µm is not recommended for a standard screw thread by this method due to the fact that dimensional allowance of many metric threaded fasteners normally does not permit it.If the size of the fastener is large enough to economically use the rack-plating process,then the latter shall be used to obtain this thickness requirement.If heavier coatings are required,allowance for the deposit buildup must be made during the manufacture of fasteners.6.3.3Applicability to Wood Screws and Thread Forming Screws —Any classification code in Table 2may be applied to screws that cut or form their own threads.6.4Hydrogen Embrittlement Relief :6.4.1Requirement for Baking —Coated fasteners made from steel heat treated to a specified hardness of 40HRC or above,case-hardened steel fasteners,and fasteners with captive wash-ers made from hardened steel,shall be baked to minimize the risk of hydrogen embrittlement.Unless otherwise specified by the purchaser,baking is not mandatory for fasteners with specified maximum hardness below 40HRC.N OTE 2—With proper care many steel fasteners can be plated without baking by correlating process conditions to the susceptibility of the fastener material to hydrogen embrittlement,and by applying adequate process control procedures,such as those outlined in X4.2.Test Method F 1940is a recognized verification method for process control to minimize the risk of hydrogen embrittlement.Upon agreement between the supplier and the purchaser,this test method can be used as a basis for determining if baking should be mandated in a controlled process environment.6.4.2Baking Conditions —At the time of publication of this specification it was not considered possible to give an exact baking duration.Eight hours is considered a typical example of baking duration.However,upon agreement between the pur-chaser and the manufacturer,baking times between 2and 24h at temperatures of 175to 235°C (350to 450°F)are suitable depending on the type and size of the fastener,geometry,TABLE 3Designation of Chromate FinishDesignationType Typical AppearanceA Clear Transparent colorless with slight iridescenceB Blue-bright Transparent with a bluish tinge and slight iridescenceC Yellow Yellow iridescentD Opaque Olive green,shading to brown or bronzeE Black Black with slight iridescenceFOrganicAny of the above plus organictopcoatmechanical properties,cleaning process and cathodic effi-ciency of the electroplating process used.The baking condi-tions shall be selected based on the results of recognized embrittlement test procedures such as Test Methods F1940, F1624,F606,or NASM1312-5.6.4.2.1Bake time and temperatures may require lowering to minimize the risk of solid or liquid metal embrittlement resulting from alloy compositions such as those containing lead or from the lower melting point of cadmium320°C(610°F)in comparison to zinc419°C(786°F).6.4.2.2Fasteners must be baked within4h,preferably1h after electroplating.Baking to relieve hydrogen embrittlement must be performed prior to the application of the chromate finish because temperatures above65°C(150°F)damage the chromatefilm thereby negating its performance.6.4.3Hydrogen Embrittlement Testing—Hydrogen em-brittlement testing is mandatory for fasteners with a specified hardness of40HRC or above,unless the electroplating process has been qualified in accordance with Test Method F1940(that is,the process has been shown not to cause embrittlement for a given product or class of product).This specification does not require mandatory testing of fasteners having a specified hardness below40HRC,unless otherwise specified by the purchaser.7.Dimensional Requirements7.1Threaded components,except those with spaced and forming threads,supplied for electrodeposited coating shall comply with ASME B1.13M.Screw threads that are specifi-cally manufactured to allow the application of12µm or greater coating thickness by the barrel-plating process,must adhere to a special allowance specified by the manufacturer or in ASME B1.13M.The other dimensional characteristics shall be as specified on the applicable standard or drawing.It should be noted that modifications to the threads of a fastener could affect its properties or performance,or both.Refer to Appendix X3 for further information on effects of coating on pitch diameter, allowances and tolerances for external and internal threads.8.Sampling8.1Sampling for coating thickness,salt spray and embrittle-ment testing shall be conducted based on lot size in accordance with Guide F1470.9.Test Methods9.1Coating Thickness—Unless otherwise specified,the re-quirement to measure coating thickness is applicable to sig-nificant surfaces only.The test methods for determining the coating thickness are defined in Test Methods B487,B499, B504,B567,B568,Guide B659or Practice E376as applicable.9.2Embrittlement Test Method—The embrittlement test method shall conform to those specified in Test Method F1940 for process verification,or Test Methods F606,F1624,or NASM-1312-5for product testing.9.3Corrosion Resistance—The requirement to determine corrosion resistance is applicable to significant surfaces only. When specified in the contract or purchase order,salt spray testing shall be conducted in accordance with Practice B117. To secure uniformity of results,samples shall be aged at room temperature for24h before being subjected to the salt spray test.10.Electroplating Processes10.1Two electroplating processes are most commonly used to apply a metallic coating by electrodeposition on threaded fasteners:barrel-plating and rack-plating.When threadfit or thread integrity,or both,is a concern for externally threaded fasteners,rack-plating is preferable to barrel-plating.Refer to Appendix X1.11.Keywords11.1chromatefinish;electrodeposited coating;fasteners; hydrogen embrittlement relief;hydrogen embrittlement test-ing;surfacetreatmentANNEX(Mandatory Information)A1.NEUTRAL SALT SPRAY PERFORMANCETABLE A1.1Classification Code and Neutral Salt Spray Corrosion Protection Performance of Zinc and Cadmium CoatingsClassification Code Minimum Coating Thickness(µm)Chromate Finish DesignationFirst Appearance of White Corrosion Product,(hour)First Appearance of Red Rust Cadmium,(hour)First Appearance of Red Rust Zinc,(hour)Fe/Zn or Fe/Cd 3A 3AA 32412Fe/Zn or Fe/Cd 3B B 62412Fe/Zn or Fe/Cd 3C C 243624Fe/Zn or Fe/Cd 3D D 243624Fe/Zn or Fe/Cd 5A 5A 64824Fe/Zn or Fe/Cd 5B B 127236Fe/Zn or Fe/Cd 5C C 4812072Fe/Zn or Fe/Cd 5D D 7216896Fe/Zn or Fe/Cd 5E E 1272Fe/Zn or Fe/Cd 8A 8A 69648Fe/Zn or Fe/Cd 8B B 2412072Fe/Zn or Fe/Cd 8C C 72168120Fe/Zn or Fe/Cd 8D D 96192144Fe/Zn or Fe/Cd 8E E 2412072Fe/Zn or Fe/Cd 12A 12A 614472Fe/Zn or Fe/Cd 12B B 2419296Fe/Zn or Fe/Cd 12C C 72240144Fe/Zn or Fe/Cd 12D D 96264168Fe/ZnorFe/Cd12BkE2419296ALow coating thickness impairs chromate adhesion and performance.TABLE A1.2Classification Code and Neutral Salt Spray Corrosion Protection Performance of Zinc-Cobalt CoatingsClassification CodeMinimum Coating Thickness (µm)Chromate Finish DesignationFirstAppearance of Zinc Alloy Corrosion Product (hour)FirstAppearance of Red Rust (hour)Fe/Zn-Co 5C 5C 96240Fe/Zn-Co 5D D 96240Fe/Zn-Co 5E E 100240Fe/Zn-Co 5F F 196340Fe/Zn-Co 8C 8C 96240Fe/Zn-Co 8D D 96240Fe/Zn-Co 8E E 100240Fe/Zn-Co 8F F 200340Fe/Zn-Co 12B 12B 12240Fe/Zn-Co 12C C 96400Fe/Zn-Co 12D D 96400Fe/Zn-Co 12E E 100400Fe/Zn-Co12FF196500APPENDIXES(Nonmandatory Information)X1.STANDARD ELECTRODEPOSITION PROCESSESX1.1Barrel-Plating Process —The preparation and metallic coating of threaded fasteners is usually accomplished by the barrel-plating process.In this process,quantities of an item are placed within a containment vessel,called a barrel.The barrel is designed to move the group of items,together,through each of the process steps,allowing ready ingress and egress of processing solutions and rinses.As the barrel is moved through the process steps,it is also rotated such that the individual items are constantly cascading over one another.This can damage the external threads of fasteners.The effect of thread damage is worse on heavy fine threaded fasteners than on light coarse threaded fasteners.In some of the process steps,notably the electrocleaning and electroplating steps,an electric current is applied to the group of items.The cascading action randomly exposes the surface of each individual piece to the process electrodes while also maintaining electrical continuity between all the parts.The local coating thickness on a part is a result of the electrical current density at that location.Therefore,the coating thickness on an individual screw or bolt tends to be greatest at the extremities (head and threaded tip).The extremi-ties being the high current density areas receive the greatest coating thickness.In contrast,the center or recesses such as the bottom of the threads,which are the low current density areas,receive the lowest coating thickness.This phenomenon is accentuated with increasing length and decreasing diameter of the screw or bolt.The extremity-to-center coating thickness ratio increases with increasing length and decreasing diameter,but is also a function of process parameters such as plating solution chemistry and efficiency,anodic/cathodic efficiency,average current density and plating time.TABLE A1.3Classification Code and Neutral Salt Spray Corrosion Protection Performance of Zinc-Nickel CoatingsClassification CodeMinimum Coating Thickness (µm)Chromate Finish DesignationFirstAppearance of Zinc Alloy Corrosion Product (hour)FirstAppearance of Red Rust (hour)Fe/Zn-Ni 5B 5B 20150Fe/Zn-Ni 5C C 120500Fe/Zn-Ni 5D D 180750Fe/Zn-Ni 5E E 100500Fe/Zn-Ni 5B/F B/F 150300Fe/Zn-Ni 5C/F C/F 240620Fe/Zn-Ni 5D/F D/F 3001000Fe/Zn-Ni 5E/F E/F 220620Fe/Zn-Ni 8B 8B 20240Fe/Zn-Ni 8C C 120720Fe/Zn-Ni 8D D 180960Fe/Zn-Ni 8E E 100720Fe/Zn-Ni 8B/F B/F 150400Fe/Zn-Ni 8C/F C/F 240840Fe/Zn-Ni 8D/F D/F 3001200Fe/Zn-Ni 8E/F E/F 220840Fe/Zn-Ni 12B 12B 20500Fe/Zn-Ni 12C C 120960Fe/Zn-Ni 12D D 1801000Fe/Zn-Ni 12E E 100960Fe/Zn-Ni 12B/F B/F 150620Fe/Zn-Ni 12C/F C/F 2401080Fe/Zn-Ni 12D/F D/F 3001500Fe/Zn-Ni12E/FE/F2201080TABLE A1.4Classification Code and Neutral Salt Spray Corrosion Protection Performance of Zinc-Iron CoatingsClassification CodeMinimum Coating Thickness (µm)Chromate Finish DesignationFirstAppearance of Zinc Alloy Corrosion Product (hour)FirstAppearance of Red Rust (hour)Fe/Zn-Co 5E 5E 144312Fe/Zn-Co 8E 8E 144312Fe/Zn-Co 12E12E144480X1.2Rack-Plating Process —The preparation and metallic coating of threaded fasteners can be accomplished by the rack-plating process,particularly on large size fasteners where thread fit and/or damage is a concern,or for smaller size fasteners when it is economically feasible.In this process,quantities of an item are placed on a support,called a rack.The rack is designed to move the group of items,together,through each of the process steps,allowing ready ingress and egress of processing solutions and rinses.In some of the process steps,notably the electrocleaning and electroplating steps,an electric current is applied to the group of items.The electrical continuity is maintained between the parts by the rack itself.The average current density is usually low enough such that the extremity-to-center coating thickness ratio is much lower than with barrel-plating.The external thread damage is also mini-mized in comparison to barrel-plating due to the absence of tumbling.X2.GUIDELINES FOR CHOOSING BETWEEN BARREL-PLATING AND RACK-PLATINGX2.1Table X2.1indicates the recommended electroplating process for each size of externally threaded metric fasteners for all thickness classes in Table 2.For internally threaded fasteners barrel-plating is generally suitable.X3.COATING ACCOMMODATION TOLERANCES FOR EXTERNALLY AND INTERNALLY THREADED FASTENERSX3.1Short screws and bolts are those with a length-to-diameter ratio equal to or less than 5.Long screws and bolts have a length-to-diameter ratio greater than 5but less than 10.Special processing is normally required for bolts with a ratio greater than 10in order to minimize the extremity-to-center thickness ratio.X3.2This specification does not impose maximum thick-ness values on high current density areas,where the coating thickness tends to be the greatest.On an externally threaded fastener this occurs at the threaded tip.Measuring coating thickness on the threaded portion of a fastener is possible but impractical for in-process quality control verification.For this reason the control mechanism specified in this document is by means of GO thread gauges.Nevertheless Table X3.1,which is supplied as an informative guideline,illustrates the maximum coating thickness permitted by the allowance for tolerance classes 6g and 4g6g.N OTE X3.1—The following information is based on ASME B1.13M .That standard should be consulted for more detailed information.X3.3Size limits for standard tolerance classes 6g and 4g6g apply prior to coating.The external thread allowance may thusbe used to accommodate the coating thickness on threaded fasteners,provided the maximum coating thickness is no more than 1⁄4of the allowance (see Fig.X3.1).Thus,threads after coating are subject to acceptance using a class 6h GO gauge for plated 6g class external threads and 4h6h GO gauge for plated 4g6g class external threads respectively.Class 6g and 4g6g shall be used as respective NOT-GO gauges.X3.4In certain cases size limits must be adjusted,within the tolerances,prior to coating,in order to insure proper thread fit.This applies to the following cases:X3.4.1Standard internal threads,because they provide no allowance for coating thickness.X3.4.2Where the external thread has no allowance,such as in class h external threads.X3.4.3Where allowance must be maintained after coating for trouble free thread fit.X3.5Table X3.1provides maximum coating thickness values based only on the allowance for external thread toler-ance classes 6g and 4g6g.It assumes that the external thread pitch diameter is at the maximum and that the internal thread pitch diameter is at the minimum of the tolerance.TABLE X2.1Recommended Electroplating Process for Each Size of Externally Threaded Metric FastenersN OTE 1—Barrel-plating process (B)and rack-plating process (R).Diameter (D),(in.)Length (L)L #5D5D <L #10D10D <L #20D20D <L #30DL >30D M1.6-M4B B B B R M5-M6B B B R R M8-M10B B B R R M12B B R R R M14B B R R R M16B B R R R M20B R R R R M24R R R R R M30-M100RRRRRTABLE X3.1Coating Accommodation Tolerances for ExternallyThreaded Class 6g and 4g6g Metric FastenersThread Pitch,mm Diameter,(in.)Pitch Diameter Allowance for 6g and 6g4g Tolerance Positions,(µm)Maximum Allowable Coating Thickness on Threaded Tip(µm)0.35M1.6–1940.4M2–1940.45M2.5–2050.5M3–2050.6M3.5–2150.7M4–2250.8M5–2461M6–2661.25M8–2871.5M10–3281.75M12–3482M14,M16–3892.5M20–42103M24–48123.5M30–53134M36–60154.5M42–63155M48–71175.5M56–75186M64,M72,M80,M90,M100–8020FIG.X3.1Metric Tolerance System for ScrewThreadsX4.APPLICATION REQUIREMENTSX4.1Cleaning of Basis Metal—Thorough cleaning of the basis metal is essential in order to ensure satisfactory adhesion, appearance and corrosion resistance of the coating.X4.2Hydrogen Embrittlement Risk Management:X4.2.1Process Considerations—The following are some general recommendations for managing the risk of hydrogen embrittlement.For more detailed information refer to IFI-142. X4.2.1.1Clean the fasteners in non-cathodic alkaline solu-tions and in inhibited acid solutions.X4.2.1.2Use abrasive cleaners for fasteners having a hard-ness of40HRC or above and case hardened fasteners.X4.2.1.3Manage anode/cathode surface area and efficiency, resulting in proper control of applied current densities.High current densities increase hydrogen charging.X4.2.1.4Use high efficiency plating processes such as zinc chloride or acid cadmiumX4.2.1.5Control the plating bath temperature to minimize the use of brighteners.X4.2.1.6Select raw materials with a low susceptibility to hydrogen embrittlement by controlling steel chemistry,micro-structure and mechanical properties.X4.2.2Process Control Verification—Test Method F1940 should be used as a test method for process control to minimize the risk of hydrogen embrittlement.Periodic inspections should be conducted according to a specified test plan.The test plan should be designed based upon the specific characteristics of a process,and upon agreement between the purchaser and the manufacturer.The testing frequency should initially estab-lish and subsequently verify over time,the ability of a process to produce parts that do not have the potential for hydrogen embrittlement.PARISON OF THE REQUIREMENTS OF SPECIFICATION F1941M–00VERSUS ISO4042–99X5.1Table X5.1provides the main differences that exist between Specification F1941M–00versus ISO4042–99.In many cases,both standards do not use the same numbering system to address a similar provision.If needed,the reader must refer to the related paragraph(s)of each standard in its entirety to fully appreciate thecomparison.。

添加LaCl3对电沉积Ni-S涂层结构和电化学性能的影响袁铁锤;周科朝;李瑞迪【摘要】Nickel-sulphur coating electrodes were prepared on foam nickel substrates by electrodeposition method in a modified Watts using thiourea (TU) and LaCl3 as sulphur source and additive, respectively. Adsorption effect of LaCl3 on the electrochemical activities, grain sizes, textures and microstructure of Ni-S coatings were characterized by means of SEM, XRD and electrochemical methods. The results show that LaCl3 can inhibit growth of coatings. The Ni-S coatings obtained from bath containing LaCl3 have larger surface area and much smaller grain sizes than those from the bath without additive. Ni-S alloy coating as a cathode for alkaline water electrolysis exhibits higher hydrogen evolution activities and better corrosion resistant performance. The hydrogen evolution overpotential of Ni-S coatings deposited at 3 g/L LaCl3 is 38 mV lower than that of the bath without additive. In the meantime, the Ni-S coatings have lower activation energy, which is 35.522 kJ/mol, and high electrochemical stability during long-term electrolysis.%以硫脲为硫源、LaC13为添加剂,采用改进的Watt浴体系在泡沫镍基体上电沉积制备Ni-S涂层电极,采用SEM观察涂层表面形貌,采用XRD分析涂层结构,电化学测试方法研究涂层的电化学行为.研究结果表明:La3+在电沉积过程中对晶粒生长起阻碍作用,能够促进沉积层的晶粒细化,同时增大了沉积层的比表面积.所制备的涂层在碱性介质下具有较高的析氢活性和耐腐蚀性能.当镀液中LaCl3质量浓度为3g/L时,制备的Ni-S涂层析氢过电位降低约38 mV,电极反应活化能为35.522 kJ/mol,在长时间水电解实验中具有较高的电化学活性和稳定性.【期刊名称】《中南大学学报（自然科学版）》【年(卷),期】2011(042)008【总页数】6页(P2285-2290)【关键词】LaCl3;Ni-S涂层;电沉积;析氢性能【作者】袁铁锤;周科朝;李瑞迪【作者单位】中南大学粉末冶金国家重点实验室,湖南长沙,410083;中南大学粉末冶金国家重点实验室,湖南长沙,410083;中南大学粉末冶金国家重点实验室,湖南长沙,410083【正文语种】中文【中图分类】TQ153.2氢能源作为一种高效、洁净和理想的二次能源已受到了世界各国的广泛关注。

Mechanical and electrical dataMechanical dataHousing material:Copper zinc alloy (CuZn), die-cast zinc (GD-Zn)Housing surface:Nickel-plated/thick layer passivated (can be coated)Insulating body:Polyamide (PA 66)Contact material:Copper zinc alloy (CuZn)Contact surface:Nickel-plated (Ni) with gold coating (Au)Contact connection method:Crimp versionSealing and O-ring:Fluorocarbon rubber (FKM)Ambient temperature:-40°C ... 130°CCable entry:Cable and coupler connectors for an outer cable diameter of 7.5 - 18 mm,shieldedType of locking:M23 SPEEDCON screw lockingMech. insertion/withdrawal cycles:Default: 100Protection class:IP67 when lockedElectrical dataNumber of positions13 (4+4+4+PE), CAT513 (8++4+PE) Contacts4+4+4+PE8+4+PE Contact Ø[mm]0.8 1.0 2.0 2.0 1.0 2.0 2.0 Litz wire cross sectionsCable and coupler connectors:Max. cable Ø of 18 mm[mm2]0.08 ... 0.50.06 … 1.00.25 … 4.00.25 … 4.00.06 … 1.00.25 … 4.00.25 … 4.0 Device connectors:[mm2]0.08 ... 0.50.06 … 1.00.25 … 4.00.25 … 4.00.06 … 1.00.25 … 4.00.25 … 4.0 Nominal current per contact at 25°C 1) 3.6830-830–Specifications according to DIN EN 61984:2009–Rated voltage[V AC/DC]5050630/850-50630/850–Test/surge voltage[kV AC] 1.5 1.56- 1.56–Surge voltage category III IIIPollution degree 2)33 Installation height[m]Up to 3000Up to 3000Cable clamping area 3)Max. Ø [mm]18181)The effective current carrying capacity must be determined using a derating curve, if necessary, according to the application.2)The values specified assume that the connector pair is correctly locked and is only disconnected for testing and maintenance purposes. If the connector is unlocked and exposed to ambient conditions, and if there is a danger of pollution, the connector must be sealed using a protective cap ≥ IP54.3)The cable clamping areas specified on the following pages may vary depending on the cable material/structure. Selection and testing is the responsibility of the user.100PHOENIX CONTACT4321B C AD7856For further information and full technical data, visit /productsPin assignments and codingContact chamber numbering(view of plug-in side)Number of positionsPinSocket13-pos., CAT5(4 + 4 + 4 + PE)Crimp13-pos.(8 + 4 + PE)Crimp101PHOENIX CONTACTSelection guideM23 hybrid connectors up to30A/630V AC/850V DC, crimp ranges up to 4 mm 2–Cable connectors –Coupler connectors–Device connectors (device flanges)The connectors are supplied pre-assembled and are complemented by the respective crimp contacts.The product chart provides an overview of the available components.Connector type SPEEDCON fast locking system, see page 104.Cable connectorsCoupler connectorsS h i e l d e dS h i e l d e dS h i e l d e dDevice connectorsSee page 106.Straight,see page 107.Angled, rotatable,flange dimensions: 26 mm x 26 mm, see page 108.M23 x 1 standard interlocking,see page 105.Angled, rotatable,flange dimensions: 28 mm x 28 mm see page 108.102PHOENIX CONTACTFor further information and full technical data, visit /productsCrimping pliers with digital display for turnedcrimp contacts,see page 159.Socket contactsTurned, see page 109.Pin contactsTurned, see page 109.Note:For reasons of safety, only socket contactsmay be used in the live part of the connector.T ools/accessoriesCrimp contactsAccessoriesColor rings for individually marking the connectors,see page 164.Allhousingscanbefittedwithpinorsocketcrimpcontacts103PHOENIX CONTACTOrdering dataOrdering dataDescriptionCable clamping areaOrder No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.4 x signal + CAT58 x signal 4 x signal + CAT58 x signal Cable connector, with contact carrier, without contacts, crimp connection Universal gasket 7.5 mm ... 18 mm162151711621524116215291162153417.5 mm ... 9 mm 162152011621525116215301162153519 mm ... 12 mm 1621521116215261162153111621536112 mm ... 15 mm 1621522116215271162153211621537115 mm ... 18 mm 16215231162152811621533116215381Accessories AccessoriesCrimp contactsSee page 109See page 109Color rings, 50 pcs. in set (to be ordered separately)See Catalog 2, page 367See Catalog 2, page 367dimension A = 0 mm104PHOENIX CONTACTCable connector, socket assembly Cable connector, pin assembly–4 x power + PE, 4 x signal, 4 x data –4 x power + PE, 8 x signalSPEEDCON fast locking systemFor further information and full technical data, visit /productsOrdering dataOrdering dataDescriptionCable clamping areaOrder No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.4 x signal + CAT58 x signal 4 x signal + CAT58 x signal Cable connector, with contact carrier, without contacts, crimp connection Universal gasket 7.5 mm ... 18 mm162199711622002116220071162201217.5 mm ... 9 mm 162199811622003116220081162201319 mm ... 12 mm 1621999116220041162200911622014112 mm ... 15 mm 1622000116220051162201011622015115 mm ... 18 mm 16220011162200611622011116220161Accessories AccessoriesCrimp contactsSee page 109See page 109Color rings, 50 pcs. in set (to be ordered separately)See Catalog 2, page 367See Catalog 2, page 367105PHOENIX CONTACTCable connector, socket assembly Cable connector, pin assembly–4 x power + PE, 4 x signal, 4 x data –4 x power + PE, 8 x signalstandard interlockingOrdering dataOrdering dataDescriptionCable clamping areaOrder No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.4 x signal + CAT58 x signal 4 x signal + CAT58 x signal Coupler connector, with contact carrier, without contacts, crimp connection Universal gasket 7.5 mm ... 18 mm162153911621544116215491162155417.5 mm ... 9 mm 162154011621545116215501162155519 mm ... 12 mm 1621541116215461162155111621556112 mm ... 15 mm 1621542116215471162155211621557115 mm ... 18 mm 16215431162154811621553116215581Accessories AccessoriesCrimp contactsSee page 109See page 109Color rings, 50 pcs. in set (to be ordered separately)See Catalog 2, page 367See Catalog 2, page 367dimension A = 0 mm106PHOENIX CONTACTCoupler connector, socket assembly Coupler connector, pin assembly–4 x power + PE, 4 x signal, 4 x data –4 x power + PE, 8 x signalFor further information and full technical data, visit /productsOrdering dataOrdering dataDescriptionOrder No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.4 x signal + CAT58 x signal 4 x signal + CAT58 x signal Device connector, with contact carrier, without contacts Flange dimensions: 26 mm x 26 mm16215671162156811621569116215701Accessories AccessoriesCrimp contactsSee page 109See page 109Color rings, 50 pcs. in set (to be ordered separately)See Catalog 2, page 367See Catalog 2, page 367107PHOENIX CONTACTDevice connector, straight,socket assembly Device connector, straight,pin assembly–4 x power + PE, 4 x signal, 4 x data –4 x power + PE, 8 x signalM23 device connector, hybrid, straightOrdering dataOrdering dataDescriptionOrder No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.Order No.Pcs. / Pkt.4 x signal + CAT58 x signal 4 x signal + CAT58 x signal Device connector, with contact carrier, without contacts Flange dimensions: 26 mm x 26 mm16215631162156411621565116215661Device connector, with contact carrier, without contacts Flange dimensions: 28 mm x 28 mm16215591162156011621561116215621Accessories AccessoriesCrimp contactsSee page 109See page 109Color rings, 50 pcs. in set (to be ordered separately)See Catalog 2, page 367See Catalog 2, page 367108PHOENIX CONTACTDevice connector, angled, rotatable, socket assembly Device connector, angled, rotatable, pin assembly–4 x power + PE, 4 x signal, 4 x data –4 x power + PE, 8 x signal–Housing can be freely rotated by 310°M23 device connector, hybrid, angled, rotatableFor further information and full technical data, visit /productsOrdering dataOrdering dataDescriptionConnection cross section[mm²]Type Order No.Pcs. / Pkt.Type Order No.Pcs. / Pkt.Contacts, Ø 0.8 mm 0.08 mm² ... 0.25 mm²SF-08KS0101621571100SF-08KP01016215741000.34 mm² ... 0.5 mm²SF-08KS0201621573100SF-08KP0201621575100Contacts, Ø 1.0 mm0.06 mm² ... 0.25 mm²ST-10KS0101618239100ST-10KP01016182551000.34 mm² ... 0.5 mm²ST-10KS0201618251100ST-10KP02016182561000.5 mm² ... 1.0 mm²ST-10KS0301618254100ST-10KP0301618261100Contacts, Ø 2.0 mm0.25 mm²... 1.0 mm²SF-20KS021*********SF-20KP0211621579501.0 mm² ... 2.5 mm²SF-20KS022*********SF-20KP0221621580502.5 mm² ... 4.0 mm²SF-20KS023162157850SF-20KP023162158150109PHOENIX CONTACTCrimp contacts, socket Crimp contacts, pinCrimp contacts。

Zinc±cobalt alloy electrodeposition from chloride baths R.FRATESI,G.ROVENTI,G.GIULIANI,Dipartimento di Scienze dei Materiali e della Terra,UniversitaÁdi Ancona,via Brecce Bianche,60131Ancona,ItalyC.R.TOMACHUKDepartamento de Engenharia de Materiais,Faculdade de Engenharia MecaÃnica,Universidade Estadual de Campinas,CEP13081-970,C.P.6122Campinas,SaÄo Paulo,BrazilReceived29July1996;revised21November1996Electrodeposition of Zn±Co alloys on iron substrate from chloride baths under galvanostatic and potentiostatic conditions were carried out.Current density,temperature and cobalt percentage in the bath were found to strongly in¯uence the composition of the deposits and their morphology. Changes in potentials,current e ciency and partial current densities were studied.The results show that the shift in potential and in the cobalt percentage of the deposits,for a particular current density during galvanostatic electrodeposition,does not always correspond to the transition from normal to anomalous codeposition.This shift is attributed to zinc ion discharge,which passes from underpo-tential to thermodynamic conditions.In the range of potentials for the underpotential deposition of zinc,the electrodeposition of zinc±cobalt alloys is discussed,emphasizing the in¯uence of the elec-trode potential on the composition and microstructure of the deposits.1.IntroductionThe electrodeposition of Zn alloys with group eight metals(Ni,Co and Fe)has recently been attracting interest because of the high corrosion resistance compared to that of pure zinc.The electrodeposition of these alloys is considered a codeposition of anomalous type,according to the Brenner de®nition [1];that is,the less noble metal deposits preferably on the cathode with respect to the more noble one.The operating conditions such as current density,tem-perature,pH,organic additives,bu er capacity, concentration of all solution components etc.lead to changes in the kinetics of electrodeposition,compo-sition and morphology of the coatings,as well as changes in their physico-mechanical characteristics [2±7].Therefore,normal codeposition is possible, even in particular electrodeposition conditions[8]. Several hypotheses have been advanced to explain the anomalous codeposition of alloys.The ideas are focused on phenomena occurring on the cathode surface.Dahms and Croll[9],who studied the anomalous electrodeposition of Fe±Ni alloy,con-cluded that the discharge of nickel is hindered by the formation of ferrous hydroxide on the electrode surface.Higashi et al.and Decroly[2,10,11]pro-posed the hydroxide suppression mechanism to ex-plain the anomalous codeposition of Zn±Co alloy in a sulfate bath.The discharge of the cobalt is inhibited by the formation of a zinc hydroxide®lm which o ers resistance to the transport of the Co2+ions.On the contrary Co(OH)2is not formed because the pH does not reach a critical value for precipitation.However,not all researchers agree on this mech-anism.Nicol and Philip[12]suggested that under-potential deposition(UPD)of the less noble metal on the cathode surface suppresses the deposition of the more noble metal.The term`underpotential deposi-tion'is used for the deposition of metal species on a foreign substrate in a potential region which is more positive than the equilibrium potential of the bulk deposit.Swathirajan[13]found that the strong inhi-bition of nickel deposition in the Zn±Ni alloy elec-trodeposition is due to submonolayer amounts of underpotential deposited zinc.Previously[3,8,14],anomalous codeposition of Zn±Ni and Zn±Co alloys has been treated,emphasiz-ing the importance of the kinetic parameters of the cathodic reactions:the iron group metals are gener-ally characterized by very low exchange current densities and re¯ect`electrochemical inertia'[15], unlike zinc,which shows high exchange current density.By studying the electrodeposition of Zn±Ni alloys from baths containing NH4Cl,no increase in the partial current of hydrogen reduction was ob-served at the potential values from which anomalous codeposition begins;this fact,plus the formation of zinc ammonium complexes,seems to exclude the precipitation of zinc hydroxide at the electrode sur-face.These results are supported by Mathias et al. [16,17].They found that,on using the Roehl bath (pH1.6),the electrodeposition of Zn±Ni alloys is anomalous even though the hydrogen current is not high enough to raise the interfacial pH much above the bulk pH,as would be necessary for the formation of Zn(OH)2.These authors calculated that the zincJOURNAL OF APPLIED ELECTROCHEMISTRY27(1997)1088±10940021-891XÓ1997Chapman&Hall1088exchange current density is®ve orders of magnitude higher than that of nickel and attributed the anom-alous codeposition to the intrinsically slow nickel kinetics.In the present work,the codeposition of Zn±Co alloys from a chloride bath has been studied.The bath was free of additives such as levellers or bright-eners since they can strongly in¯uence the composi-tion and the morphology of the alloys deposited on the cathode.2.Experimental detailsZn±Co alloys were obtained at various temperatures (25,40and55°C),under galvanostatic and potent-iostatic conditions using baths of the following com-position:ZnCl231.1±70.0g dm A3;CoCl2á6H2O90.7±15.2g dm A3(M tot37.4g dm A3);H3BO326g dm A3; KCl220g dm A3(pH4.3,4.2and3.9for baths with Co10,30and60%,respectively).Boric acid is used extensively in Zn±Co and Zn±Ni alloy electro-depositions,as a bu er to prevent the pH rise at the electrode surface;however,the function of H3BO3is a controversial subject[18,19].Tests with only cobalt or zinc,maintaining the total metal quantity and the other components of the bath constant,were also carried out.Solutions were prepared with doubly distilled water and analytical grade reagents. Electrodeposits were obtained on both sides of mild steel discs,1mm thick(exposed area15cm2). Before electrodeposition,the samples were smoothed with emery paper and any grease was removed from their surface by anodic and cathodic electrolysis for 2min in an aqueous NaOH60g dm A3solution at4V against graphite anodes.The samples were then neutralized in a2%HCl solution and rinsed with distilled water.A PVC cell1dm3in capacity was used.The steel cathode was centrally positioned,whereas two zinc anodes(total area150cm2)were symmetrically po-sitioned with respect to the central cathode.Before immersion in the bath,the zinc anodes were im-mersed for3h without current¯ow,in a solution of similar composition at40°C.The zinc sheets were coated with a dark cobalt layer,so avoiding the de-pletion of cobalt in the bath due to its cementation on the zinc anodes.Cathode potential measurements were performed during electrodeposition using a Ag/ AgCl reference electrode.Polarization was applied when the cathode was immersed in the bath and electrolysis was continued until deposits at least6l m thick were obtained.During the electrodeposition, the cathodic solution was mechanically stirred.The amount of electrical charge during potentiostatic tests was registered by means of a coulometer AMEL model731.At the end of each deposition,the disc cathodes were thoroughly washed with water and then ethanol,hot air dried and weighed.To determine the percentage composition of the electrodeposited alloys,the deposits were stripped in a minimum volume of1:3HCl solution and analysed for cobalt and zinc by means of inductively coupled plasma spectroscopy(ICPS).By means of Faraday's law,the partial currents of zinc and cobalt were cal-culated and their respective polarization curves were plotted.The morphology of the deposits was observed by means of scanning electron microscopy(SEM).The deposited phases were analysed by X-ray di raction with Cu K a(k 15.4nm)and identi®ed by powder di raction®le card(JCPDS).All the tests were repeated three times with good agreement of the results.3.Results and discussionThe data shown in Fig.1were obtained by gal-vanostatic electrodeposition at25°C.They show the in¯uence of current density on the chemical compo-sition of the deposits obtained from baths containing di erent percentages of cobalt ions.The percentage of Co present in the baths and deposits,indicated by Co b and Co d was calculated as follows:Co a%Co a gCo Zn a gÂ100The trend of the curves is similar to that already known for codepositions of anomalous type[2,8]:the percentage of cobalt deposited on the cathode de-pends on the cobalt/zinc concentration ratio in the bath and is quite constant for a large range of current density,where the deposition of zinc and cobalt is of anomalous type.At low current densities the per-centage of cobalt in the deposits increases abruptly reaching values of almost100%and the codeposition becomes normal.The value of current density corre-sponding to the transition from normal to anomalous codeposition is called the transition current density (i T)and it depends,at constant temperature,on the bath chemical composition.In Fig.1the letters(a), (b)and(c)show the points of the respective curves where the percentage of cobalt in the deposits isequalZINC±COBALT ALLOY ELECTRODEPOSITION1089to that in the bath;the`imaginary'line interpolating the three points represents the composition reference line(CRL).With increase in cobalt/zinc concentration ratio,a higher current density is necessary for anom-alous deposition to occur.The temperature strongly a ects the composition of the deposits,as shown in Fig.2.On increasing the temperature,the sharp decrease in cobalt percentage in the coatings occurs at higher current densities and this is associated with the abrupt shift of cathodic potential toward more negative values.At tempera-tures of25and40°C the transition from normal to anomalous codeposition(points A and B in Fig.2) corresponds to the rapid shift in the cobalt percentage of the deposits and in the cathodic potentials.In the Zn±Co electrodeposition carried out at55°C,at about3.6mA cm A2the cobalt percentage of the de-posits decreases abruptly,but it still remains higher than the cobalt percentage in the bath.In spite of thesharp shift in cathodic potential,normal/anomalous transition does not take place.This behaviour is more evident in the electrodeposition carried out at55°C, but in a solution with a cobalt ion concentration of 60%(Fig.3).In this case the characteristic shift in the cathodic potential,as well as the reduction in cobalt percentage of the deposits at about35mA cm A2,are still less marked and the codeposition always remains normal even at relatively high current densities (50mA cm A2).The alloy current e ciency is almost 100%and therefore the current e ciency of hydrogen is very low throughout the whole current density range studied.Figures2and3show that only for some experimental conditions does the shift in po-tential and in the cobalt percentage of deposits cor-respond to the transition from normal to anomalous electrodeposition.Only in these latter cases,the cur-rent density corresponding to the sharp shift in cathodic potential is the transition current. Figure4shows the polarization curves obtained by galvanostatic tests at55°C using baths containing di erent cobalt/zinc concentration ratios.The curves obtained from the baths containing only zinc or co-balt ions are also indicated.The cobalt deposition from the solution containing only cobalt ions starts at about A550mV,while the zinc deposition from baths containing only zinc ions starts at about A1000mV. The alloy polarization curves are close to the curve for Co at low current densities,while they are very close to the curve for Zn after the rapid shift in po-tential.The sharp variations in cathodic potential are due to the zinc ions discharge which passes from underpotential to thermodynamic conditions.The galvanostatic tests do not shed light on the phe-nomena that occur on the electrode in the range in which the potential rapidly changes. Therefore,potentiostatic electrodeposition was carried out in the current range where the cathodic potential is unstable(Fig.5).The curves related to pure zinc or pure cobalt are similar to those obtained by galvanostatic tests.The zinc and the cobalt ions separately begin deposition only at their respective equilibrium potential of the bulk deposit.Thecurves 1090R.FRATESI ET AL.due to the deposition of Zn±Co alloys,compared to those of galvanostatic type,are more detailed.At more positive potential values the curves are similar to those of pure cobalt deposition,but around ±800to ±850mV the current signi®cantly drops and then,at potential values more negative than ±950mV it again sharply increases.The total electrolysis current together with the partial currents related to cobalt,zinc and hydrogen and also the zinc percentage in the alloy deposit ob-tained in the potential range ±660to ±1100mV are shown in Fig.6.In the operating conditions related to Fig.6,the trend of the current density due to the alloy is quite similar to the partial current density of cobalt up to about ±800mV,and the deposits contain more than 90%of cobalt in the range ±600to ±800mV.The zinc deposition starts around ±700mV and its per-centage in the deposits increases as the cathodic po-tential change toward more negative values.The zincreduction in this ®eld of potential is assisted by the presence of cobalt ions in the solution,indeed the partial current density of zinc depends on the per-centage of cobalt in the bath,when the other exper-imental conditions are kept constant (Fig.7);a connection between i Co and i Zn was found previously,though for di erent experimental conditions [20].How the cobalt supports the underpotential elec-trodeposition of zinc is not clear at the moment.At a potential of ±800mV vs Ag/AgCl,the percentage of zinc in the deposits is about 14%and the partial current density of cobalt reaches a maximum value;at ±830mV the percentage of zinc in the deposits reaches 19%and the partial current densities of co-balt and of zinc begin to decrease.The zinc percent-age in the deposits remains quite constant until about ±900mV (Zn d ~23%),then it rapidly begins to in-crease again together with the partial current of zinc (i Zn ).The cathodic reduction of zinc prevails over cobalt reduction only at potential values more nega-tive than about ±970mV,where it begins to discharge in thermodynamic conditions.In these conditions,however,the codeposition is not always of anoma-lous type.Using the same bath,but carrying out the tests at 25°C (Fig.8),the trend of the curves appears the same as in Fig.6.At this temperature value the in-hibition of the cobalt ions discharge starts when the zinc percentage in the deposits is about 15%.In this case however,on the contrary to what happens in the operating condition related to Fig.6,the transition from underpotential to thermodynamic electro-deposition corresponds to the transition from normal to anomalous codeposition.In the range of potentials where the zinc reduces in underpotential conditions,the deposition of Zn±Co alloys is always of normal type.It must be emphasized that,in the range ±700~±800mV,in spite of the high percentage of zinc (higher than 10%),the inhibition of cobalt ions dis-charge does notoccur.ZINC±COBALT ALLOY ELECTRODEPOSITION 1091The increase in pH at the cathodic interface is generally considered responsible for the inhibition of cobalt discharge in the hydroxide suppression mech-anism,as mentioned in the introduction [2,5].The present work does not seem to con®rm this theory since the partial current density of hydrogen remains quite constant and very low (Figs 6and 8).Therefore,the inhibition of cobalt ion reduction in these oper-ating conditions does not seem connected with an increase in pH.The observation carried out by SEM on the sur-faces of the deposits obtained at the potential values of Fig.6,are shown in Figs 9±13.Deposits obtained at ±700mV (Fig.9,Zn d 0.5%)are formed of pure cobalt and are not cracked,according to the solu-bility of Zn in Co,which is less than 3%[18].The coatings obtained at ±750mV are cracked (Fig.10,Zn d 8%);in the range ±800to ±830mV the deposits are cracked and do not adhere to the steel substrate (Fig.11,Zn d 14%).At more negative potential val-ues,in the range where the zinc percentage remains quite constant and the partial current density of co-balt decreases,the deposits are still cracked,but they adhere again to the steel substrate (Fig.12,Zn d 23%).The cracking of the cobalt deposits with inclusion of zinc above 3%was found by other authors [10,11];the higher percentage of zinc in the alloy produces more internal stresses in the deposits,until a change in the crystalline structure occurs which reduces these internal stresses.The maximum in the internal stresses coincides with the maximum in the current density of cobalt (i Co ).These deposits show a brittle behaviour with the surface fracture that looks like a vitreous fracture (Fig.13).At potentials where the zinc can reduce in thermodynamic conditions and the partial current density of zinc becomes higher than the partial current density of cobalt,the deposition of compact and well formed zinc-rich deposits occurs (Fig.14,Zn d 60%).The in¯uence of the electrode potential on the deposition of various phases of di erent zinc com-position from the same electrolyte was also foundbyFig.9.Microstructure of zinc±cobalt alloy obtained by potentio-static electrodeposition at ±700mV vs Ag/AgCl.Co b 30%;T 55°C;Zn d0.5%.Fig.10.Microstructure of zinc±cobalt alloy obtained by potent-iostatic electrodeposition at ±750mV vs Ag/AgCl.Co b 30%;T =55°C;Zn d8%.Fig.11.Microstructure of zinc±cobalt alloy obtained by potent-iostatic electrodeposition at ±800mV vs Ag/AgCl.Co b 30%;T 55°C;Zn d 14%.1092R.FRATESI ET AL.other authors for Zn±Ni and Zn±Co alloys elec-trodeposition [13,21].The X-ray analysis do not always permit to iden-tify the phases present in the coatings (Fig.15).De-posits of only cobalt are not crystalline,the peaks have very low intensity and can be attributed to low content of crystalline a Co in the quite completely amorphous deposit (Fig.15,line a).The presence of zinc in the range 0.5~23%makes the deposits more and more amorphous (Fig.15lines b,c,d,e).When the zinc reaches 60%,the deposits become crystalline and the zinc peaks clearly appear (Fig.15,line f ).4.ConclusionsThe deposition of Zn±Co alloys is generally a code-position of anomalous type,but,in particular elec-trodeposition conditions,it is possible to obtain normal codeposition.The shift in potential and in cobalt percentage in the deposits,which occur at a particular current density during galvanostatic electrodeposition,doesnot always correspond to the transition from normal to anomalous codeposition.The sharp variations in cathodic potential are due to the zinc ions discharge which passes from underpotential to thermodynamic conditions.In the underpotential deposition,the electrode potential determines the deposition of various phases of di erent composition.The inclusion of zinc above 3%causes cracking of the cobalt deposits and the further increase in the percentage of zinc in the alloy produces more internal stresses in the deposits.TheFig.12.Microstructure of zinc±cobalt alloy obtained by potent-iostatic electrodeposition at ±870mV vs Ag/AgCl.Co b 30%;T 55°C;Zn d23%.Fig.13.Fracture of Zn±Co alloy (Zn d 23%)obtained by bending of the coatinglayer.Fig.14.Microstructure of zinc±cobalt alloy obtained by potent-iostatic electrodeposition at ±1000mV vs Ag/AgCl.Co b 30%;T 55°C;Zn d23%.ZINC±COBALT ALLOY ELECTRODEPOSITION 1093inhibition of the cobalt ions discharge starts only when the zinc percentage in the deposits reaches about15%.The maximum in the internal stresses coincides with the maximum in the current density of cobalt(i Co).At potentials where the zinc can reduce in ther-modynamic conditions,deposits containing more than60%zinc become compact and well formed, even when the codeposition is still of normal type.AcknowledgementsThe research was supported by Conselho Nacional de Desenvolvimento Cientõ®co e TecnoloÂgico(CNPq), Brasil.References[1] A.Brenner,`Electrodeposition of alloys',vols I and II,Academic Press,New York and London(1963). [2]K.Higashi,H.Fukushima,T.Urokawa,T.Adaniya andK.Matsudo,J.Electrochem.Soc.128(1981)2081. [3]L.Felloni,R.Fratesi,E.Quadrini and G.Roventi,J.Appl.Electrochem.17(1987)574.[4]L.Felloni,R.Fratesi and G.Roventi,Proceedings of theXXII International Metals Congress,Bologna,Italy(17±19May1988),p.687.[5]H.Fukushima,T.Akiyama,K.Higashi,R.Kammel andM.Karimkhani,Metall.42(1988)242.[6]R.Albalat,E.GoÂmez,C.Muller,M.Sarret,E.ValleÂs andJ.Pregonas,J.Appl.Electrochem.20(1989)529. [7]R.Albalat,E.GoÂmez,C.Muller,M.Sarret,E.ValleÂs andJ.Pregonas,ibid.20(1990)635.[8]R.Fratesi and G.Roventi,J.Appl.Electrochem.22(1992)657.[9]H.Dahms and I.M.Croll,J.Electrochem.Soc.112(1965)771.[10]J.Mindowicz,C.Capel-Boute and C.Decroly,Electro-chim.Acta10(1965)901.[11]M.Yunus,C.Capel-Boute and C.Decroly,ibid.10(1965)885.[12]M.I.Nicol and H.I.Philip,J.Electroanal.Chem.70(1976)233.[13]S.Swathirajan,ibid.221(1987)211.[14]R.Fratesi and G.Roventi,Mater.Chem.Phys.23(1989)529.[15]R.Piontelli,in`Atlas of Electrochemical Equilibria inAqueous Solutions'(edited by M.Pourbaix),NACE,Huston,Texas(1974),p.11.[16]M.F.Mathias and T.W.Chapman,J.Electrochem.Soc.134(1987)1408.[17]Idem,ibid.137(1990)102.[18] C.Karwas and T.Hepel,J.Electrochem.Soc.136(1989)1672.[19]M.Pushpavanam and K.Balakrishnan,J.Appl.Electro-chem.26(1996)283.[20]M.Maja,N.Penazzi,R.Fratesi and G.Roventi,J.Electrochem.Soc.129(1982)2695.[21]M.L.AlcalaÂ,E.GoÂmez and E.ValleÂs,J.Electroanal.Chem.370(1994)73.1094R.FRATESI ET AL.。

e h welding 躺焊earing 出耳子early slag 初渣earth metal 稀土金属earthy browncoal 土状褐煤earthy iron ore 泥状铁矿easy magnetization axis 易磁化方向ebr 电子束重熔eccentric bottom tapping 偏心炉底出钢eccentric converter 偏心炉口转炉eccentric covering 偏心被覆eccentric press 偏心压机eccentric tapping 偏心出钢economizer 节约装置eddy current flaw detection 涡帘陷探测eddy currents 涡流eddy mill 旋涡研磨机eddy mill powder 旋涡研磨粉eddy motion 涡了动eddyloss 涡琉耗edenborn reel 伊登堡式线材卷取机edge beveling 边缘倒棱edge chamfering 边缘倒棱edge crack 边裂edge dislocation 刃型位错edge planer 刨边机edge preparation 边缘加工edge runner mill 刃型连续研磨机edge shaver 刨边机edge stability 棱边强度edge strength 棱边强度edge trimmers 剪边机edge trimming 切边edge waviness 边缘波纹edger 立辊轧机edging 侧压下量edging groove 立轧孔型edging pass 立轧道次edging roll 立辊edging stand 立辊轧机eduction pipe 排气管effective area 有效面积effective diameter 有效直径effective distribution coefficient 有效分布系数effective particle density 颗粒有效密度effective porosity 有效孔隙度effective pressure 有效压力effective stress 有效应力effervescent deep drawing steel 深冲用沸腾钢effervescent steel 沸腾钢effervescing steel 沸腾钢efficiency 效率efficient deformation 有效形变efflorescence 风化effluents 废水effusion 瘤effusion method 隙透法einsteinium 锿ejection force 推顶力ejection pressure 脱模压力ejector 喷射器elastic aftereffect 弹性后效elastic afterworking 弹性后效elastic body 弹性体elastic constant 弹性常数elastic deformation 弹性变形elastic energy 弹性能elastic fatigue 弹性疲劳elastic force 弹力elastic hysteresis 弹性滞后elastic limit 弹性极限elastic modulus 弹性模数elastic plastic fracture mechanics 弹性塑性断裂力学elastic range 弹性区elastic region 弹性区elastic strain 弹性变形elastic stress 弹性应力elasticity 弹性elbow 弯管electric arc 电弧electric arc furnace 电弧炉electric arc welding 电弧焊electric brazing 电热钎焊electric conduction 电导electric conductivity 导电率electric corundum 电熔刚玉electric energy 电能electric furnace 电炉electric furnace brazing 电炉内钎焊electric furnace shop 电炉车间electric furnace slag 电炉渣electric heating 电加热electric melting 电热熔炼electric pig iron 电炉生铁electric pig iron furnace 炼铁电炉electric power 电力electric power consumption 电力消耗量electric precipitator 电气集尘器electric reduction furnace 电热还原炉electric reduction process 电热还原法electric resistance 电阻electric resistance annealing 电阻退火electric resistance brazing 电阻钎焊electric resistance thermometer 电阻温度计electric resistance welding 电阻焊electric smelting 电炉熔炼electric steel 电炉钢electric steel plant 电炉炼钢车间electric steelmaking furnace 电气炼钢炉electric vacuum furnace 真空电炉electric weld pipe mill 电焊钢管轧管机electric welded pipe 电焊管electric welding 电焊electric welding machine 电焊机electrical contact alloy 电气接点合金electrical properties 电气性质electrical sheet 电工钢板electroanalysis 电解分析electrobrightening 电解抛光electrocapillarity 电毛细现象electrochemical action 电化酌electrochemical analysis 电化分析electrochemical corrosion 电解腐蚀electrochemical equivalent 电化当量electrochemical polarization 电化学极化electrochemical potential 电化学势electrochemical reduction 电化还原electrochemical series 电化序electrochemistry 电化学electrocolor process 电解着色法electrocrystallization 电结晶electrode 电极;焊条electrode coke 电极焦electrode crater 电极端弧坑electrode for cast iron 铸铁焊条electrode for underwater cutting 水中割条electrode force 电极压力electrode holder 电焊钳electrode potential 电极电势electrode reaction 电极反应electrode stub 焊条残头electrode tip 电极端electrode welding 手工电弧焊electrode wire 焊丝electrodeposit 电镀层electrodeposited alloy 电解沉积合金electrodeposited coating 电镀层electrodeposition 电解沉积electrodes circle diameter 电极圆直径electrodiffusion 电扩散electroerosion machining 电侵蚀加工electroextraction 电解提取electrofilter 电过滤器electrogalvanizing 电解镀锌electrogalvanizing line 电镀锌椎线electrogas arc welding 气电焊electrogranodising 电解磷酸盐处理electroless plating 非电解浸镀electrolysis 电解electrolyte 电解液electrolytic analysis 电解分析electrolytic bath 电解浴electrolytic cell 电解槽electrolytic cleaning 电解清洗electrolytic cleaning line 电解清洗椎线electrolytic coloring 电解着色electrolytic copper 电解铜electrolytic copper refining 铜的电解精炼electrolytic corrosion 电解腐蚀electrolytic degreasing 电解脱脂electrolytic deposit 电解沉积物electrolytic deposition 电解沉积electrolytic dissociation 电离electrolytic dissolution 电解溶解electrolytic etching 电解浸蚀electrolytic extraction 电解提取electrolytic furnace 电解炉electrolytic iron 电解铁electrolytic leaching 电解浸出electrolytic lead 电解铅electrolytic lead refining 铅电解精炼electrolytic manganese 电解锰electrolytic metal 电解金属electrolytic nickel 电解镍electrolytic oxidation 电解氧化electrolytic parting 电解分离electrolytic pickling 电解酸洗electrolytic plant 电解车间electrolytic polarization 电解极化electrolytic polishing 电解抛光electrolytic powder 电解粉末electrolytic process 电解法electrolytic rectifier 电解用整流electrolytic reduction 电解还原electrolytic refining 电解精炼electrolytic separation 电解分离electrolytic slime 电解泥electrolytic solution 电解溶液electrolytic solution tension 电溶压electrolytic stripping 电解剥离electrolytic tinning 电解镀锡electrolytic tinning line 电镀锡椎线electrolytic tinplate 电镀锡板electrolytic zinc 电解锌electrolytic zinc plating line 电镀锌椎线electrolyzer 电解槽electromagnet 电磁铁electromagnetic coagulation 电磁凝结electromagnetic field 电磁场electromagnetic forming 电磁成形electromagnetic lens 电磁透镜electromagnetic radiation 电磁辐射electromagnetic separation 电磁分离electromagnetic stirring 电磁搅拌electromagnetism 电磁学electromechanical scale 机电天平electrometallurgy 电冶金electrometer 静电计electromotive force 电动势electron 电子;埃雷克特龙镁基合金electron affinity 电子亲和力electron beam 电子束electron beam furnace 电子束熔炼炉electron beam gun 电子枪electron beam hardening 电子束淬火electron beam melting 电子束熔炼electron beam microprobe 电子束显微探头electron beam remelting 电子束重熔electron beam welding 电子线束焊接electron bombardment 电子轰击electron diffraction 电子衍射electron diffraction analysis 电子衍射分析electron diffraction pattern 电子衍射图electron emission microscopy 电子发射显微镜检查法electron microprobe analyser 电子显微探针分析仪electron microprobe analysis 电子探针分析electron microscope 电子显微镜electron microscopy 电子显微镜检查法electron optics 电子光学electron probe analyzer 电子探针分析器electron probe microanalysis 电子探针分析electron shell 电子壳electron spectroscopy 电子光谱学electronegative element 阴电性元素electronegativity 负电性electronic computer 电脑electropercussive welding 电冲桓接electrophoresis 电泳electroplating 电镀electroplating bath 电镀槽electropolishing 电解抛光electropositive element 阳电性元素electropositive metal 正电性金属electroreduction 电解还原electrorefining 电解精炼electroslag process 电渣法electroslag refining furnace 电渣重熔炉electroslag remelting 电渣重熔electroslag remelting furnace 电渣重熔炉electroslag remelting process 电渣重熔法electroslag resistance furnace 电渣电阻炉electroslag topping process 电渣顶部加热法electroslag welding 电渣焊electrospark machining 电火花加工electrostatic cleaning 静电除尘electrostatic potential 静电位electrostatic precipitator 静电集尘器electrostatic separation 静电选矿electrostatic welding 静电焊electrostriction 电致伸缩electrothermal furnace 电热炉electrothermal oven 电热炉electrothermal process 电热法electrothermics 电热学electrothermy 电热学electrotype metal 电铸极金属electrovalent linkage 离子键electrum 埃列克特鲁金银合金element 元素elemental body 单质体elementary analysis 元素分析elementary cell 单位晶胞elevating piler 升降堆垛台elevator 升降机elin hafergut welding 躺焊elinvar 埃林瓦合金elongated grain 伸长晶粒elongating mill 延伸轧管机elongation 延伸elongation at rupture 破断伸长elongator 延伸轧管机elred process 电热还原法eluate 洗出液eluent 洗提液elution 洗提elution process 洗提法elutriation 淘析elutriator 淘析器embolite 氯溴银矿embossing 压纹embrittlement 脆化embrittlement temperature 脆化温度emergency ladle 备用罐emergency repair 紧急修理emergency shears 事故剪切机emergency taphole 备用紧急出铁口emergency tuyere 备用紧急风口emery 刚砂emery cloth 刚砂布emery paper 砂纸emery wheel 砂轮emf method 电动势法emissary dislocations 发射位错emission 放射emission analysis 放射分析emissive power 辐射本领emissivity 辐射系数;辐射本领emplectite 硫铜苍铅矿emplectum 硫铜苍铅矿emulsification 乳化emulsified oil quenching 乳化油淬火emulsifier 乳化剂emulsifying agent 乳化剂emulsion 乳浊液emulsoid 乳胶体enamel 瓷漆enameled wire 漆包线enameling 搪瓷enameling sheet 搪瓷钢板enantiotropism 互变现象enargite 硫砷铜矿enclosure 夹杂物end cropping 切头end product 最终产物end quench curve 乔米尼曲线end quench hardenability test 末端淬透性试验end quenching 顶端淬火end return 端部周边焊end shears 剪头机end sizing 最终定径end tab 引出板endless mill 无头轧机endless rolling 无头轧制endogenous inclusion 内生夹杂物endoscope 内视镜endothermic reaction 吸热反应endurance 耐久性endurance bending strength 弯曲疲劳强度endurance failure 疲劳断裂endurance limit 疲劳极限endurance ratio 疲劳比endurance test 疲劳试验endurance testing machine 疲劳试验机energizer 活化剂energy 能energy balance 能量平衡energy band 能带energy barrier 能垒energy conservation 能量守恒energy density 能量密度energy distribution 能量分布energy efficiency 能效率energy exchange 能量交换energy hill 能垒energy level 能级energy loss 能量损失energy spectrum 能谱energy state 能态energy transfer 能量传移engineering cast iron 机破造用铸铁enriched element 富集元素enriched uranium 浓缩铀enrichment 富集enthalpy 焓enthalpy of formation 生成焓enthalpy of fusion 熔化焓enthalpy of melting 熔化焓enthalpy of mixing 混合焓entropy 熵entry accumulator 入口贮料坑entry guide 进口导板entry guide box 进口导极盒entry roll cone 进口辊圆锥entry side 进料侧entry table 输入辊道envelope 外壳;保护介质environment protection 环境保护environmental pollution 环境污染epitaxial film 外延生长膜epitaxial layer 外延生长膜epitaxy 外延生长epoxy coat 环氧涂层epoxy resin 环氧尸epsomite 泻利盐equal angle 等边角钢equation of state 状态方程式equiaxed crystal 等轴晶体equicohesive temperature 等内聚温度equilibrium 平衡equilibrium blast cupola 平衡鼓风化铁炉equilibrium concentration 平衡浓度equilibrium conditions 平衡条件equilibrium constant 平衡常数equilibrium diagram 平衡状态图equilibrium electrode potential 平衡电极电位equilibrium phase 平衡相equilibrium pressure 平衡压力equilibrium state 平衡状态equilibrium system 平衡系equipartition 平匀分配equipment 设备equipotential line 等势线equipotential surface 等位面equivalence point 当量点equivalent 当量equivalent carbon content 碳当量equivalent concentration 当量浓度equivalent conductivity 当量导电率equivalent diameter 等效直径equivalent fuel 等价燃料equivalent weight 当量erbium 铒erection welding 工地焊接erichsen test 埃里克森杯突试验erosion 侵蚀erosion resistance 抗腐蚀性erythrite 钴华esr 电渣重熔esr process 电渣重熔法etch figure 侵蚀图etch pit 蚀坑etch test 腐蚀试验etch test cut 腐蚀试片etchant 腐蚀剂etched slice 腐蚀试片etching 腐蚀etching crack 腐蚀裂纹etching pattern 侵蚀图etching reagent 腐蚀剂ether 醚ethyl alcohol 乙醇euchroite 翠砷铜矿europium 铕eutectic 共晶体eutectic alloy 共晶合金eutectic carbides 共晶碳化物eutectic cast iron 共晶铸铁eutectic cementite 共晶渗碳体eutectic composition 共晶成分eutectic line 共晶线eutectic melting 共晶熔化eutectic mixture 共晶混合物eutectic point 共晶点eutectic reaction 共晶反应eutectic solder 共晶软焊料eutectic structure 共晶组织eutectic temperature 共晶温度eutectic transformation 共晶转变eutectic trough 共晶谷eutectic valley 共晶谷eutectoid 共析体eutectoid alloy 共析合金eutectoid cementite 共析渗碳体eutectoid composition 共析成分eutectoid decomposition 共析分解eutectoid horizontal 共析线eutectoid line 共析线eutectoid point 共析点eutectoid reaction 共析反应eutectoid steel 共析钢eutectoid structure 共析组织eutectoid transformation 共析转变evacuation 抽空evaporating dish 蒸发皿evaporation 蒸发evaporation coating 蒸发镀层evaporation concentration 蒸发浓缩evaporation cooling 汽化冷却evaporation loss 蒸发损失evaporation residue 蒸发残渣evaporator 蒸发器even fracture 平坦断口examination 试验excess air 过剩空气excess air coefficient 过剩空气系数excess enthalpy 过剩焓excess free energy 过剩自由能excess oxygen flame 过剩氧火焰excess vacancy 过剩空位exchange energy 交换能exchange reaction 交换反应exchanger 交换器换热器excitation 激励excitation energy 激励能excitation level 激励能级excitation potential 激励电位excited atom 受激原子excited state 激励状态exfoliation 剥落exhaust 排气exhaust fan 抽风机exhaust gas 排出的气体exhaust heat boiler 废热锅炉exhaust pipe 排气管exhaust steam 排汽exhaust valve 排气阀exhauster 抽风机exit accumulator 出口贮料坑exit gas 出口气体exit guide 出口导板exit roll cone 轧辊出口圆锥exit side 出料侧exogas 放热型气体exogenous inclusion 处来夹杂exothermal reaction 放热反应exothermic ferroalloy 放热性铁合金exothermic gas 放热型气体expanded blister 扩张气泡expanded crack 扩大裂纹expanded skin 轧制氧化皮expander 扩管装置expanding bar 扩孔锻造用心轴expanding machine 扩管装置expanding mill 扩径机expansibility 膨胀性expansion 膨胀expansion joint 伸缩缝expansion test 扩口试验experimental furnace 试验炉experimental plant 试验装置explosion 爆发explosion forming 爆炸成形explosion welding 爆炸焊接explosion working 爆炸加工explosive compacting 爆炸压制explosive hardening treatment 爆炸硬化处理explosivity 爆炸性exponent 指数exponent curve 指数曲线exponential function 指数函数exsiccator 保干器extended dislocation 扩展位错extensibility 延伸性extension 延伸extensometer 延伸仪extent 范围external combustion stove 外燃式热风炉external defect 外部缺陷external desulfurization 炉外脱硫external force 外力external resistance 外电阻extra deep drawing 极深冲extra deep drawing steel 极深冲钢extra furnace dephosphorization 炉外脱磷extra half plane 多余的半原子平面extract 提取物extractability 可萃性extraction 萃取extraction agent 提取剂extraction column 萃取塔extraction liquid 萃取液extraction method 萃取法extractive distillation 萃取蒸馏镏extractive matter 萃取物extractive metallurgy 提炼冶金extractive solvent 萃取溶剂extractor 萃取器extrahard steel 极硬钢extrasoft steel 特软钢extrinsic stacking fault 外来层错extrolling 挤压延extruded electrode 机械压涂的焊条extruded section 挤压型材extruded tube 挤压管extruder 挤压机extruding 挤压extruding press 挤压机extrusion 挤压extrusion die 挤压模extrusion ram 挤压杆extrusion stem 挤压杆exudate 渗出物exudation 渗出eyesight 观察孔。

电镀主要是用于各类产品的表面处理效果。

电镀分为水镀以及真空镀。

镀（Plating);电镀（Electroplating)一般我们跟国外客户谈到这个问题就用这个单词.自催化镀（Auto-catalytic Plating)，一般称为"化学镀(Chemical Plating）"、"无电镀(Electroless Plating)"等浸渍镀（Immersion Plating）氧化又是另一种表面处理效果,主要用于铝件阳极氧化(Anodizing）化学转化层（Chemical Conversion Coating)）钢铁发蓝(Blackening）,俗称”煲黑钢铁磷化（Phosphating）铬酸盐处理(Chromating）金属染色（Metal Colouring）涂装(Paint Finishing)，包括各种涂装如手工涂装、静电涂装、电泳涂装等热浸镀(Hot dip)热浸镀锌（Galvanizing）,俗称”铅水热浸镀锡（Tinning）乾式镀法物理气相沈积法(Physical Vapor Deposition)真空镀(Vacuum Plating)。

离子镀(Ion Plating），P）化学气相沈积法（Chemical Vapor Deposition）1、水电镀：Galvanic plating2、主要工艺是将需电镀的产品放入化学电镀液中进行电镀。

2、真空离子镀，又称真空镀膜：Ion plating3。

一般适用范围较广，如ABS料、ABS+PC料、PC料的产品.同时因其工艺流程复杂、环境、设备要求高,单价比水电镀昂贵。

现对其工艺流程作简要介绍：产品表面清洁、去静电-—>喷底漆--〉烘烤底漆--〉真空镀膜—->喷面漆—-〉烘烤面漆-—〉包装。

以下資料來源世贸人才网电镀electroplating 利用电解在制件表面形成均匀、致密、结合良好的金属或合金沉积层的过程。

Vol. 35 No. 6功 能 高 分 子 学 报2022 年 12 月Journal of Functional Polymers493文章编号： 1008-9357(2022)06-0493-16DOI: 10.14133/ki.1008-9357.20220103001功能高分子材料在锌负极保护中的应用张馨壬， 曲昌镇， 苏延霞， 张秀海， 刘兴蕊， 邱玉倩， 王洪强， 徐 飞（西北工业大学材料学院，凝固技术国家重点实验室，纳米能源材料研究中心，西安710072）摘 要： 水系锌离子电池因安全性高、成本低廉、环境友好等优点，在大规模储能等领域展现出广阔的应用前景。

然而，锌负极与电解液界面处存在严重的枝晶生长和副反应等问题，严重制约了其实际应用。

功能高分子材料具有丰富可调的功能基团、快速传导锌离子的能力、优异的柔韧性、良好的成膜与黏附性等优势，是应用于锌负极保护的一类重要材料。

本文综述了功能高分子材料应用于锌负极保护的最新研究进展，并对其未来的发展进行了展望。

关键词： 锌负极；锌枝晶；功能高分子；涂层；水系锌离子电池中图分类号： O63 文献标志码： ARecent Progress of Functional Polymers for Zinc Anodes ProtectionZHANG Xinren, QU Changzhen, SU Yanxia, ZHANG Xiuhai, LIU Xingrui, QIU Yuqian, WANG Hongqiang, XU Fei （State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China）Abstract:Aqueous zinc ion batteries deliver the merits of high safety, abundant resources, low cost and environmental friendliness, thus exhibiting broad application prospects in large-scale energy storage system. However, serious dendrite growth and side reactions occur at the Zn anode/electrolyte interphase, giving rise to the poor cycling life and Coulombic efficiency. These problems severely hinder the practical applications of zinc ion batteries. Therefore, constructing of suitable protective layers is one of the most important pathways to inhibit zinc dendrite and side reactions like hydrogen evolution, benefiting from their ability to isolate the zinc anode from the electrolyte while allowing rapid Zn2+ migration and facilitating uniform electrodeposition. Functional polymers show potentials as promising Zn anode protective layers, owing to their adjustable functional groups, rapid Zn2+ conduction, excellent flexibility, good film-formation and adhesion. This review summarizes the progress of functional polymers serving as zinc protective layers, and finally presents a perspective on the future development in this field.Key words: zinc anode； zinc dendrite； functional polymer； coating layer； aqueous zinc ion battery在双碳目标的加持下，新型电化学储能正迎来全新的发展机遇。