ASTM_B_343_-_92a_2014.pdf

Designation:B34392a(Reapproved 2014)Endorsed by AmericanElectroplaters SocietyEndorsed by NationalAssociation of Metal FinishersStandard Practice forPreparation of Nickel for Electroplating with Nickel1This standard is issued under the fixed designation B343;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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 This practice summarizes well-known,generally practi-cal methods for producing adherent electrodeposits of nickelon nickel.1.2 Electrodeposits of nickel on nickel are produced,forexample,to improve the performance of decorative coatings,toreclaim electroplated parts that are defective,and to resumenickel electroplating after interruptions in processing.Interrup-tions may be deliberate,for example,to machine the electrode-posit at an intermediate stage in the electrodeposition of thicknickel coatings.The interruptions may be unintentional,forexample,resulting from equipment and power failures.1.3 To ensure good adhesion of nickel to nickel,precautionsshould be taken to avoid biopolar effects during nickel elec-troplating.This is of particular importance in return-typeautomatic plating machines where one rack follows anotherrack closely.Bipolar effects can be avoided by making theracks cathodic while they are entering or leaving the nickeltank.Separate current control on entry and exit stations isdesirable.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns,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.Types of Nickel2.1 The types of nickel for which an overplate of nickel maybe desired are dull nickel,semi-bright nickel,bright nickel,andnickel strike.Variations in these types may possibly requirespecial handling.2.2 Surface conditions of the nickel may vary as follows:2.2.1 Freshly electroplated surfaces that are still wet withelectroplating solution or rinse water(see 5.1),2.2.2 Freshly electroplated surfaces that have been allowedto dry(see 5.2),2.2.3 Buffed,polished,or machine-ground surfaces(see5.3),and2.2.4 Surfaces that have been given a reverse-current treat-ment in an alkaline solution for cleaning or possibly strippingan overplate of chromium(see 5.4).3.Cleaning3.1 The following cleaning treatments may be used for allconditions and types of electrodeposited nickel.The choice ofthe procedure will be governed largely by the condition of thesurface.3.1.1 DegreasingDegreasing is used to remove the bulkof grease,oil,and buffing compounds that may be present onthe surface.The cleaning may be effected with vapordegreasing,organic solvents,emulsion cleaners,or soakcleaner.3.1.2 Electrolytic Alkaline CleaningRemoval of finaltraces of dirt,grease,and oil is accomplished best withelectrolytic alkaline cleaning.The solution may be either aproprietary cleaner or a formulated one.Since a nickel surfaceforms an oxide coating if treated anodically in an alkalinesolution,this condition must be altered in subsequent steps if itcannot be avoided.4.Activating4.1 The procedure used for etching or activating the nickelsurface usually determines the soundness of the adhesion.Thechoice of the procedure may be governed by the condition ofthe surface and possibly the type of nickel.The milder etchingtreatment should be used in the case of highly finishedsurfaces,but it may result in sacrificing maximum adhesion.The thickness of the nickel may militate against the use ofcertain etching procedures,and therefore the thickness re-moved is indicated for each procedure described in 4.2 to 4.8.4.2 Anodic Treatment in Concentrated Sulfuric Acid(Nickel removed nil).A70 mass%sulfuric acid solutioncontaining 661 mL of concentrated,96 mass%sulfuric acid1This practice is under the jurisdiction of ASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.02 onPre Treatment.Current edition approved Nov.1,2014.Published November 2014.Originallyapproved in 1960.Last previous edition approved in 2009 as B343 92a(2009).DOI:10.1520/B0343-92R14.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1(density 1.83 mL)diluted to 1 L may be used for activating thenickel surface provided the temperature of the solution is notover 30C(see Warning).When the initial mixture cools,dilute to exact volume.The time of treatment should be about1 min at a current density of 10 A/dm2.At this current densitythe nickel normally goes passive and a bright surface becomesonly slightly dull.This type of passivi