ASTM B700-2008(2014) Standard Specification for Electrodeposited Coatings of Silver for Engineering Use《工程用银电沉积覆层的标准规范》.pdf

1、Designation: B700 08 (Reapproved 2014)Standard Specification forElectrodeposited Coatings of Silver for Engineering Use1This standard is issued under the fixed designation B700; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y

2、ear of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers requirements for electrodepos-ited coatings of silver used for engineering purposes t

3、hat maybe mat, bright, or semibright and are not less than 98 % silverpurity.1.2 Coatings of silver covered by this specification areusually employed for solderable surfaces, electrical contactcharacteristics, high electrical and thermal conductivity, ther-mocompression bonding, wear resistance of l

4、oad-bearingsurfaces, and spectral reflectivity.1.3 In the Appendixes important characteristics of elec-trodeposited silver coatings are briefly described which mustbe considered when used in engineering applications, namelyelectrical conductivity (see Appendix X1), silver migration(see Appendix X2),

5、 thickness (see Appendix X3), hardness(see Appendix X4), and atmospheric tarnish (see AppendixX5).1.4 The following hazards caveat pertains only to the testmethods section of this specification: This standard does notpurport to address the safety concerns, if any, associated withits use. It is the r

6、esponsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B183 Practice for Preparation of Low-Carbon Steel forElectroplatingB242 Guide for Preparat

7、ion of High-Carbon Steel for Elec-troplatingB252 Guide for Preparation of Zinc Alloy Die Castings forElectroplating and Conversion CoatingsB253 Guide for Preparation of Aluminum Alloys for Elec-troplatingB254 Practice for Preparation of and Electroplating onStainless SteelB281 Practice for Preparati

8、on of Copper and Copper-BaseAlloys for Electroplating and Conversion CoatingsB322 Guide for Cleaning Metals Prior to ElectroplatingB343 Practice for Preparation of Nickel for Electroplatingwith NickelB374 Terminology Relating to ElectroplatingB481 Practice for Preparation of Titanium and TitaniumAll

9、oys for ElectroplatingB482 Practice for Preparation of Tungsten and TungstenAlloys for ElectroplatingB487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination ofCross SectionB499 Test Method for Measurement of Coating Thicknessesby the Magnetic Method: Nonmagn

10、etic Coatings onMagnetic Basis MetalsB504 Test Method for Measurement of Thickness of Metal-lic Coatings by the Coulometric MethodB507 Practice for Design of Articles to Be Electroplated onRacksB542 Terminology Relating to Electrical Contacts and TheirUseB567 Test Method for Measurement of Coating T

11、hicknessby the Beta Backscatter MethodB568 Test Method for Measurement of Coating Thicknessby X-Ray SpectrometryB571 Practice for Qualitative Adhesion Testing of MetallicCoatingsB578 Test Method for Microhardness of Electroplated Coat-ingsB579 Specification for Electrodeposited Coatings of Tin-Lead

12、Alloy (Solder Plate)B602 Test Method for Attribute Sampling of Metallic andInorganic CoatingsB678 Test Method for Solderability of Metallic-CoatedProductsB697 Guide for Selection of Sampling Plans for Inspectionof Electrodeposited Metallic and Inorganic CoatingsB762 Test Method of Variables Sampling

13、 of Metallic andInorganic CoatingsB849 Specification for Pre-Treatments of Iron or Steel forReducing Risk of Hydrogen Embrittlement1This specification is under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.04 on Precious

14、Metal Coatings.Current edition approved May 1, 2014. Published May 2014. Originallyapproved in 1981. Last previous edition approved in 2008 as B700 08. DOI:10.1520/B0700-08R14.2B08 For referenced ASTM standards, visit the ASTM website, www.astm.org,or contactASTM Customer Service at serviceastm.org.

15、 For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1B850 Guide for Post-Coating Treatments of Steel for Reduc-ing the Ri

16、sk of Hydrogen EmbrittlementD3951 Practice for Commercial PackagingE1004 Test Method for Determining Electrical ConductivityUsing the Electromagnetic (Eddy-Current) MethodF519 Test Method for Mechanical Hydrogen EmbrittlementEvaluation of Plating/Coating Processes and Service En-vironments3. Termino

17、logy3.1 DefinitionsMany of the terms used in this specifica-tion are defined in Terminologies B374 or B542.3.2 Definitions of Terms Specific to This Standard:3.2.1 rack-platingan electrodeposition process in whicharticles to be coated are mounted on racks or other fixturesduring the process.3.2.2 si

18、gnificant surfacessurfaces that are normallyvisible, directly or by reflection, or that are essential to theserviceability or function of the article or which can be thesource of corrosion products or tarnish films that interfere withthe function or desirable appearances of the article. Whennecessar

19、y, the significant surfaces shall be indicated on thedrawings of the parts, or by the provisions of suitably markedsamples.3.2.2.1 DiscussionVariation in the coating thickness frompoint-to-point on a coated article is an inherent characteristic ofelectroplating processes. Therefore, the coating thic

20、kness willhave to exceed the specified value at some points on thesignificant surfaces to ensure that the thickness equals orexceeds the specified value at all points. The average coatingthickness on the article usually will be greater than thatspecified; how much greater is largely determined by th

21、e shapeof the article (see Practice B507) and the characteristics of theelectroplating process. Additionally, the average coating thick-ness on an article will vary from article to article within aproduction lot. If all the articles in a production lot are to meetthe thickness requirement, the avera

22、ge coating thickness of aproduction lot as a whole will be greater than the averagenecessary to ensure that a single article meets requirements.3.2.3 strike or flasha thin, typically less than 0.25-m (10-in.) metallic coating layer between metallic coatings toimprove adhesion.3.2.4 underplatingan ap

23、plication of a metallic coatinglayer between the basis metal or substrate and the topmostmetallic coating or coatings (see 6.3.4).4. Classification4.1 Electrodeposited coatings of silver shall be classified forType based on minimum purity, Grade whether bright,semibright, or mat, Class if supplement

24、ary surface treatment isapplied, and thickness in micrometers.4.2 PuritySpecify by Type as follows:Type 199.9 % minType 299.0 % minType 398.0 % minNOTE 1Metallic or organic brighteners used for grain refinement maybe present in the electrodeposit so long as they do not interfere with thestated funct

25、ion of the coating and are acceptable to the purchaser (seeAppendix X1).4.3 Surface AppearanceSpecify by Grade in letter code asfollows:Grade A, MatElectrodeposits without luster, obtainedfrom electroplating solutions operated without the use ofbrighteners.Grade B, BrightElectrodeposits obtained by

26、the use ofbrighteners in the electroplating bath.Grade C, BrightElectrodeposits obtained by mechanicalor chemical polishing of Grade A silver coatings.Grade D, Semibright Semi-lustrous electrodeposits ob-tained by the use of addition agents in the electroplating bath.4.4 Supplementary Surface Treatm

27、ent Specify by Class inletter code as follows:Class NA finish that has had no supplementary tarnishresistant (that is, chromate) treatment (see Appendix X5).Class SA finish that has had a supplementary tarnishresistant (that is, chromate) treatment.NOTE 2Class S is not suitable for food service appl

28、ications.5. Ordering Information5.1 To make application of this standard complete, thepurchaser needs to supply the following information to theseller in the purchase order or other governing document:5.1.1 Name, designation, and year of issue of this standard.5.1.2 Type (see 4.2), Grade (see 4.3),

29、Class (see 4.4) andThickness (see 6.6 and Appendix X3).5.1.3 Nature of SubstrateIf, for example, it is highstrength steel, the need for stress relief (see 6.3.2.1) andembrittlement relief (see 6.3.5.1). If it is copper, an undercoatis needed (see S1.3) for some applications.5.1.4 Significant Surface

30、s (see section 3.2.2).5.1.5 Appearance (see 6.7).5.1.6 Underplates (see 6.3.4 and S1.3).5.1.7 Requirements and methods of testing for one or moreof the following: need for and type of test specimens (see 8.1),thickness (see 6.6, 8.2, and Appendix X3), adhesion (see 6.8and 8.3), hardness (see 6.10.1

31、and 8.7), absence of embrittle-ment (see 8.4), solderability (see 6.9 and 8.5), spectral reflec-tance (see 6.10.2 and 8.8), or electrical conductivity (see 6.10.3and 8.9).5.1.8 Sampling Plans and Quality Assurance (see Section 7and S1.2).6. Coating Requirements6.1 Nature of CoatingThe coating essent

32、ially shall besilver, considering the type specified, produced by electrode-position from aqueous electrolytes.6.2 Purity of CoatingThe coating shall meet the chemicalcomposition requirements of the specified type as defined in4.2 and measured as described in 8.6.6.3 Process:6.3.1 The basis metal sh

33、all be subjected to such cleaningprocedures as are necessary to ensure a surface satisfactory forsubsequent electroplating. Materials used for cleaning shallB700 08 (2014)2have no damaging effects on the basis metal resulting in pits,intergranular attack, stress corrosion cracking, or hydrogenembrit

34、tlement.NOTE 3For basis metal preparations, the following appropriateASTMstandards are recommended: Practices B183, B254, B281, B343, B481,and B482, and Guides B242, B252, B253, and B322.6.3.2 Preplating OperationsElectroplating shall be ap-plied after all basis metal heat treatments and mechanicalo

35、perations such as forming, machining, and joining of thearticle have been completed.NOTE 4Silver deposits may be used to facilitate mechanical opera-tions such as forming and drawing. In these applications, silver is appliedbefore such process steps.6.3.2.1 Stress Relief TreatmentParts that are made

36、 ofsteels with ultimate tensile strength of 1000 MPa or over(hardness of 31 HRC or greater) that have been machined,ground, cold-formed or cold-straightened subsequent to heattreatment, may require stress relief heat treatment when speci-fied by the purchaser, the tensile strength to be supplied by

37、thepurchaser. Specification B849 may be consulted for a list ofpretreatments that are used widely.6.3.3 StrikeThe final silver coating shall be preceded by asilver or gold strike for optimum adhesion.6.3.4 UnderplatingA nickel or nickel-alloy intermediatelayer, at least 1 m (39 -in.) thick, shall be

38、 applied before thesilver electroplate when the product being plated is made fromcopper or copper alloy. Nickel underplatings are also appliedfor other reasons.6.3.5 Post-Plating Procedures:6.3.5.1 Embrittlement ReliefParts that are made of steelswith ultimate tensile strength of 100 MPa or over (ha

39、rdness of31 HRC or greater), as well as surface-hardened parts, mayrequire post-coating hydrogen embrittlement relief bakingwhen specified by the purchaser, the tensile strength to besupplied by the purchaser. Specification B850 may be con-sulted for a list of post-treatments that are used widely.6.

40、4 Surface AppearanceThe coatings surface finish shallmeet the requirements of the specified grade defined in 4.3.6.5 Supplementary Post TreatmentThe coating shall meetthe requirements of the specified class defined in 4.4.6.6 ThicknessThe silver coating thickness on significantsurfaces shall be at l

41、east that specified (see Appendix X3) whenmeasured as described in 8.2.6.7 AppearanceSilver electroplated coated articles shallbe covered completely on all surfaces as specified in themanufacturing document and shall have a uniform appearancewith no visible defects to the extent that the nature of t

42、he basismetal and good commercial practice permit. The requirementfor uniform color or appearance need not apply for subsequentpassivation or other treatments of the silver.6.7.1 DefectsDefects in the surface of the basis metal suchas scratches, pits, non-conducting inclusions, and roll and diemarks

43、 may adversely affect the appearance and performance ofapplied coatings. Such defects that persists in the finish despitethe observance of good metal finishing practices shall not because for rejection.NOTE 5Coated finishes generally perform better in service when thesubstrate over which they are ap

44、plied is smooth and free from torn metal,inclusions, pores, and other defects. It is recommended that the specifi-cations covering the unfinished product provides limits for those defects.A metal finisher often can remove defects by means of special treatmentssuch as grinding, polishing, abrasive bl

45、asting, chemical treatments, andelectropolishing. However, these are not normal for the treatment stepspreceding application of the finish. When they are desired, they are thesubject of special agreement between the purchaser and the supplier.6.8 AdhesionThe silver coatings shall be free of blisters

46、and peeled areas indicating poor adhesion when tested inaccordance with 8.3.NOTE 6Some applications may require no separation by any mechani-cal means such as machining or milling through the interface.6.9 SolderabilityThe silver plated surfaces shall producesolder coatings which shall be bright, sm

47、ooth, and uniform. Atleast 95 % of the sample surface shall show good wetting whentested as described in 8.5.6.10 Supplementary Requirements :6.10.1 HardnessIf a hardness requirement is specified, thehardness of the silver coatings shall conform to that specifiedas measured as described in 8.7.6.10.

48、2 Spectral ReflectanceThe spectral reflectance of thesilver coatings, if required, shall conform to that specifiedwhen measured as described in 8.8.6.10.3 Electrical ConductivityThe electrical conductivityof the silver coatings, if required, shall conform to thatspecified when measured as described

49、in 8.9.7. Sampling7.1 A random sample of the size required by Test MethodB602 or Method B762 shall be selected from the inspection lot(see 7.2). The articles in the lot shall be classified as conform-ing or nonconforming to each requirement according to thecriteria of the sampling plans in the chosen method.NOTE 7Test Method B602 contains four sampling plans, three for usewith nondestructive test methods; the fourth is for use with destructive testmethods. The three methods for nondestructive tests differ in the qualitylevel they requi