ASTM B867-1995(2008) Standard Specification for Electrodeposited Coatings of Palladium-Nickel for Engineering Use《工程用钯-镍电镀层的标准规范》.pdf

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1、Designation: B 867 95 (Reapproved 2008)Standard Specification forElectrodeposited Coatings of Palladium-Nickel forEngineering Use1This standard is issued under the fixed designation B 867; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi

2、sion, the year 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 CompositionThis specification covers requirementsfor electrodeposited palladium-nickel coatings cont

3、aining be-tween 70 and 95 mass % of palladium metal. Compositecoatings consisting of palladium-nickel and a thin gold over-plate for applications involving electrical contacts are alsocovered.1.2 PropertiesPalladium is the lightest and least noble ofthe platinum group metals. Palladium-nickel is a s

4、olid solutionalloy of palladium and nickel. Electroplated palladium-nickelalloys have a density between 10 and 11.5, which is substan-tially less than electroplated gold (17.0 to 19.3) and compa-rable to electroplated pure palladium (10.5 to 11.8). This yieldsa greater volume or thickness of coating

5、 per unit mass and,consequently, some saving of metal weight. The hardnessrange of electrodeposited palladium-nickel compares favorablywith electroplated noble metals and their alloys (1, 2).2NOTE 1Electroplated deposits generally have a lower density thantheir wrought metal counterparts.Approximate

6、 Hardness (HK25)Gold 50250Palladium 75600Platinum 150550Palladium-Nickel 300650Rhodium 7501100Ruthenium 60013001.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety c

7、oncerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3B 183 Practice for Preparation of Lo

8、w-Carbon Steel forElectroplatingB 242 Guide for Preparation of High-Carbon Steel forElectroplatingB 254 Practice for Preparation of and Electroplating onStainless SteelB 281 Practice for Preparation of Copper and Copper-BaseAlloys for Electroplating and Conversion CoatingsB 322 Guide for Cleaning Me

9、tals Prior to ElectroplatingB 343 Practice for Preparation of Nickel for Electroplatingwith NickelB 374 Terminology Relating to ElectroplatingB 481 Practice for Preparation of Titanium and TitaniumAlloys for ElectroplatingB 482 Practice for Preparation of Tungsten and TungstenAlloys for Electroplati

10、ngB 487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination of CrossSectionB 488 Specification for Electrodeposited Coatings of Goldfor Engineering UsesB 489 Practice for Bend Test for Ductility of Electrodepos-ited and Autocatalytically Deposited Metal Coati

11、ngs onMetalsB 507 Practice for Design ofArticles to Be Electroplated onRacksB 542 Terminology Relating to Electrical Contacts andTheir UseB 558 Practice for Preparation of Nickel Alloys for Electro-platingB 568 Test Method for Measurement of Coating Thicknessby X-Ray SpectrometryB 571 Practice for Q

12、ualitative Adhesion Testing of MetallicCoatings1This specification is under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatings and is under the direct responsibility of Subcom-mittee B08.08.01 on Engineering Coatings.Current edition approved Aug. 1, 2008. Published September 20

13、08. Originallyapproved in 1995. Last previous edition approved in 2003 as B 867 95 (2003).2The boldface numbers in parentheses refer to the list of references at the end ofthis specification.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv

14、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.B 602 Test Method for Attribute Sampling of Metallic an

15、dInorganic CoatingsB 697 Guide for Selection of Sampling Plans for Inspectionof Electrodeposited Metallic and Inorganic CoatingsB 741 Test Method for Porosity In Gold Coatings On MetalSubstrates By Paper Electrography4B 748 Test Method for Measurement of Thickness of Me-tallic Coatings by Measuremen

16、t of Cross Section with aScanning Electron MicroscopeB 762 Test Method of Variables Sampling of Metallic andInorganic CoatingsB 765 Guide for Selection of Porosity and Gross DefectTests for Electrodeposits and Related Metallic CoatingsB 798 Test Method for Porosity in Gold or PalladiumCoatings on Me

17、tal Substrates by Gel-Bulk ElectrographyB 799 Test Method for Porosity in Gold and PalladiumCoatings by Sulfurous Acid/Sulfur-Dioxide VaporB 809 Test Method for Porosity in Metallic Coatings byHumid Sulfur Vapor (“Flowers-of-Sulfur”)B 827 Practice for Conducting Mixed Flowing Gas (MFG)Environmental

18、TestsB 845 Guide for Mixed Flowing Gas (MFG) Tests forElectrical ContactsB 849 Specification for Pre-Treatments of Iron or Steel forReducing Risk of Hydrogen EmbrittlementB 850 Guide for Post-Coating Treatments of Steel for Re-ducing the Risk of Hydrogen EmbrittlementD 1125 Test Methods for Electric

19、al Conductivity and Re-sistivity of WaterD 3951 Practice for Commercial Packaging3. Terminology3.1 Definitions: Many terms used in this specification aredefined in Terminology B 374 or B 542.3.2 Definitions of Terms Specific to This Standard:3.2.1 overplating, na coating applied onto the topmostpall

20、adium-nickel coating. The thickness of an overplating or“flash” is usually less than 0.25 m.3.2.2 significant surfaces, nthose surfaces normally vis-ible (directly or by reflection) or which are essential to theserviceability or function of the article; or which can be thesource of corrosion product

21、s or tarnish films that interfere withthe function or desirable appearance of the article. The signifi-cant surfaces shall be indicated on the drawings of the parts, orby the provision of suitably marked samples.3.2.3 underplating, na metallic coating layer or layersbetween the basis metal or substr

22、ate and the palladium-nickelcoating. The thickness of an underplating is usually greaterthan 1 m, in contrast to a strike which is thinner.4. Classification4.1 Orders for articles to be plated in accordance with thisspecification shall specify the coating system, indicating thebasis metal, the thick

23、nesses of the underplatings, the type andthickness class of the palladium-nickel coating, and the gradeof the gold overplating according to Table 1, Table 2, and Table3. See Section 7.5. Ordering Information5.1 In order to make the application of this specificationcomplete, the purchaser shall suppl

24、y the following informationto the seller in the purchase order or other governing document:5.1.1 The name, designation, and date of issue of thisspecification;5.1.2 The coating system including basis metal, composi-tion type, thickness class and gold overplate grade (see 4.1 andTable 1, Table 2, and

25、 Table 3);5.1.3 Presence, composition, and thickness of underplating(see 3.2.1). For nickel underplating see 6.5.1;5.1.4 Significant surfaces shall be defined (see 3.2.3);5.1.5 Requirements, if any, for porosity testing (see 9.6);5.1.6 (Steel parts only) Stress relief if required (see Speci-fication

26、 B 849);5.1.7 (Steel parts only) Hydrogen embrittlement relief (seeB 850 );5.1.8 Sampling plan employed (see Section 8); and,5.1.9 Requirement, if any, for surface coating cleanliness(absence of residual salts). See Appendix X6.6. Manufacture6.1 Any process that provides an electrodeposit capable of

27、meeting the specified requirements will be acceptable.6.2 Substrate:6.2.1 The surface condition of the basis metal should bespecified and should meet this specification prior to the platingof the parts.6.2.2 Defects in the surface of the basis metal, such asscratches, porosity, pits, inclusions, rol

28、l and die marks, laps,cracks, burrs, cold shuts, and roughness may adversely affectthe appearance and performance of the deposit, despite the4Withdrawn.TABLE 1 Composition TypeType Nominal Composition (Mass %) Range (Mass% Pd)I 75 % Pd/25 % Ni 7080 % PdII 80 % Pd/20 % Ni 7585 % PdIII 85 % Pd/15 % Ni

29、 8090 % PdIV 90 % Pd/10 % Ni 8595 % PdTABLE 2 Thickness ClassAThickness Class Minimum Thickness of Pd-Ni (m)0.4 0.40.5 0.50.7 0.71.0 1.01.3 1.31.5 1.52.0 2.02.5 2.53.0 3.0ASee Appendix X3 on Electrical Contact Performance Versus Thickness Class.TABLE 3 Gold OverplateAGrade TypeMIL-G-45204Hardness (C

30、ode)ThicknessRange0 No Overplate . . .1 1 (99.9 % Au min) III 90 HK25max (A) 0.050.12 m2 2 (99.7 % Au min) I 130200 HK25(C) 0.050.25 mASee Specification B 488 and Appendix X1 and Appendix X2.B 867 95 (2008)2observance of the best plating practice. Any such defects onsignificant surfaces should be br

31、ought to the attention of thesupplier and the purchaser.6.2.3 Clean the basis metal as necessary to ensure a satis-factory surface for subsequent electroplating in accordancewith Practices B 183, B 242, B 254, B 281, B 322, B 343,B 481, B 482 and B 558.6.2.4 Proper preparatory procedures and thoroug

32、h cleaningof the basis metal are essential for satisfactory adhesion andperformance of these coatings. The surface must be chemicallyclean and continuously conductive, that is, without inclusionsor other contaminants. The coatings must be smooth and as freeof scratches, gouges, nicks, and similar im

33、perfections aspossible.NOTE 2A metal finisher can often remove defects through specialtreatments such as grinding, polishing, abrasive blasting, chemical treat-ments, and electropolishing. However, these may not be normal in thetreatment steps preceding the plating, and a special agreement is indica

34、ted.6.3 If required (see 5.1.6), steel parts with a hardness greaterthan 1000 MPa (31 HRC) shall be given a suitable stress reliefheat treatment prior to plating in accordance with SpecificationB 849. Such stress relief shall not reduce the hardness to avalue below the specified minimum. Avoid acid

35、pickling ofhigh strength steels.6.3.1 Apply the coating after all basis metal preparatory heattreatments and mechanical operations on significant surfaceshave been completed.6.4 Racking:6.4.1 Position parts to allow free circulation of solution overall surfaces. The location of rack or wire marks in

36、 the coatingshould be agreed upon between the producer and supplier.6.5 Plating Process:6.5.1 Nickel UnderplatingApply a nickel underplatingbefore the palladium-nickel when the product is made fromcopper or copper alloy. Nickel underplatings are also appliedfor other reasons. See Appendix X5.NOTE 3I

37、n certain instances where high frequency analog signals areemployed, such as wave guides, the magnetic properties of nickel mayattenuate the signal. Palladium-nickel itself is non-ferromagnetic when thenickel content is less than 14 mass %.NOTE 4In applications where forming or flaring operations ar

38、e to beapplied to the plated component, a ductile nickel electrodeposit should bespecified.6.5.2 StrikesGood practice suggests the use of a palla-dium strike to follow any underplate or substrate (other thansilver or platinum) immediately prior to applying thepalladium-nickel.6.5.3 PlatingGood pract

39、ice calls for the work to beelectrically connected when entering the palladium-nickelsolution.NOTE 5Some palladium-nickel electroplating solutions attack copper.This can result in codeposition of copper impurity. The situation is furtheraggravated when low current densities are utilized. Copper can

40、beremoved from solutions by low current density electrolysis (0.1 to 0.3mA/cm2).6.5.4 Gold OverplatingApply a thin gold overplatingafter the palladium-nickel in any application in whichpalladium-nickel plated electrical connectors are mated to-gether in a contact pair. This process is necessary to p

41、reservethe performance of the contact surface. See Appendix X1 forother reasons for using a gold overplate.NOTE 6When using Type 1 gold, the thickness of the gold overplateshall not exceed 0.12 m (5 in.) due to increased risk of degradingdurability and increasing the coefficient of friction.6.5.5 Re

42、sidual SaltsFor rack and barrel plating applica-tions, residual plating salts can be removed from the articles bya clean, hot (50 to 100C) water rinse. A minimum rinse timeof 2.5 min (racks) or 5 min (barrel) is suggested. Best practicecalls for a minimum of three dragout rinses and one runningrinse

43、 with dwell times of 40 s in each station when rack platingand 80 s when barrel plating. Modern high-velocity impinge-ment type rinses can reduce this time to a few seconds. This isparticularly useful in automatic reel-to-reel applications wheredwell times are significantly reduced. See Appendix X6.

44、7. Coating Requirements Coating Requirements7.1 Nature of CoatingThe palladium-nickel deposit shallhave a minimum purity of 70 mass % palladium.7.2 CompositionThe composition of the palladium-nickelelectrodeposit shall be within 65 mass % of the specified type.7.3 AppearancePalladium-nickel coatings

45、 shall be coher-ent, continuous, and have a uniform appearance to the extentthat the nature of the basis metal and good commercialpractices permit.7.4 ThicknessEverywhere on the significant surface (see5.1), the thickness of the palladium-nickel coating shall beequal to or exceed the specified thick

46、ness. The maximumthickness, however, shall not exceed the drawing tolerance.NOTE 7The coating thickness requirement of this specification is aminimum requirement, that is, the coating thickness is required to equal orexceed the specified thickness everywhere on the significant surfaceswhile conformi

47、ng to all maximum thickness tolerances given in theengineering drawing. Variation in the coating thickness from point to pointon a coated article is an inherent characteristic of electroplating processes.The coating thickness at any single point on the significant surface,therefore, will sometimes h

48、ave to exceed the specified value in order toensure that the thickness equals or exceeds the specified value at all points.Hence, most average coating thicknesses will be greater than the specifiedvalue. How much greater is largely determined by the shape of the article(see Practice B 507) and the c

49、haracteristics of the plating process. Inaddition, the average coating thickness on products will vary from articleto article within a production lot. If all of the articles in a production lotare to meet the thickness requirement, the average coating thickness forthe production lot as a whole will be greater than the average necessary toassure that a single article meets the requirement. See 8.1.7.5 AdhesionThe palladium-nickel coatings shall be ad-herent to the substrate or underplate when tested by one of theprocedures summarized in 9.5.