ASTM_B_558_-_79_2013.pdf

Designation:B55879(Reapproved 2013)Standard Practice forPreparation of Nickel Alloys for Electroplating1This standard is issued under the fixed designation B558;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 is intended to serve as a guide forproducing adherent electrodeposits of nickel on nickel alloys.Only those methods that are well known and generally prac-ticed are included.Methods that have been used successfullybut not on a broad scale are not included.Once nickel isapplied,other metals may be electroplated on the product.1.2 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.Cleaning2.1 The following cleaning treatments may be used.Thechoice of the procedure will be governed largely by thecondition of the surface.2.1.1 Degreasing is used to remove the bulk of grease,oil,and finishing compounds that may be present on the surface.The cleaning may be vapor degreasing,solvent wash,emulsioncleaning,or soak cleaning.2.1.2 Electrolytic Alkaline Cleaning Removal of finaltraces of dirt,grease,and oil is accomplished best withelectrolytic alkaline cleaning.The solution may be either aproprietary cleaner or a formulated one.3.Activation3.1 The procedure used for activating the nickel alloysurface usually determines the soundness of the adhesion.Thechoice of treatment is governed by the condition of the surfaceand the type of alloy.A mild etching treatment should be usedon polished surfaces if a highly finished surface is required.Too mild a treatment may result in a sacrifice of maximumadhesion.3.2 Anodic-Cathodic Sulfuric AcidA25 mass%sulfuricacid solution,containing 166 mL of concentrated,93 mass%sulfuric acid(density 1.83 g/mL)diluted to 1 L is used for thisetching treatment in which the alloy is first etched anodically ata low-current density of 2 A/dm2for 10 min and then madepassive at 20 A/dm2for 2 min and finally cathodic for 2 or 3 sat 20 A/dm2.(WarningSlowly add the sulfuric acid withrapid stirring to the approximate amount of water required.)When the initial mixture cools,dilute to exact volume.Thetemperature of the solution should be in the range from 20 to25C(70 to 80F).Chemical lead may be used for theelectrodes.Rinsing should be used before electroplating.NOTE1This activation is not suitable for barrel operation.3.3 Acid-Nickel Chloride Treatment This procedure usesan anodic treatment followed by a cathodic treatment in alow-pH nickel chloride solution.The composition of thesolution is 240 g/L of nickel chloride(NiCl26H2O)and 31 mLof concentrated 31.45 mass%hydrochloric acid(density 1.16g/mL).The normal procedure is to make the alloy anodic for 2min at 3A/dm2and then cathodic for 6 min at the same currentdensity.The temperature of the solution should be in the rangefrom 20 to 25C.Nickel may be used for the electrodes.Separate tanks are recommended for the anodic and cathodicsteps to avoid contamination of solution but a single tank maybe used.Rinsing should be used before electroplating exceptwhere indicated in Table X1.1.NOTE2Nickel anode materials containing greater than 0.01%sulfurare not recommended for use in acid nickel strike baths operating at pH0.5,or lower,to avoid oxidation of sulfides by hydrochloric acid.3.4 Anodic Etching in a Low pH Watts BathThe compo-sition of the low pH Watts Bath is 360 g/L of nickel sulfate(NiSO47H2O),45 g/L of nickel chloride(NiCl26H2O),and37.5 g/L of boric acid(H3BO3).This procedure uses an anodictreatment in a low-pH(2.0)bath for 10 min at 2 A/dm2.Thecurrent is then reversed and the nickel is electroplated undernormal conditions.Electrolytic nickel may be used as theopposing electrode material.No rinsing is needed if the alloy istransferred to a chloride-containing electroplating bath.3.5 Hydrofluoric Acid EtchThis procedure consists of a10-s dip in a solution containing 500 mL of 47 mass%hydrofluoric acid diluted to 1 L at room temperature.Rinsingshould precede electroplating.4.Alloys4.1 Recommended activating treatments for specific nickelalloys are listed in the Appendix,Table X1.1.1This practice is under the jurisdiction of ASTM Committee B08 on Metallicand Inorganic Coatingsand is the direct responsibility of Subcommittee B08.02 onPre Treatment.Current edition approved Dec.1,2013.Published December 2013.Originallyapproved in 1972.Last previous edition approved in 2008 as B558 79(2008).DOI:10.1520/B0558-79R138.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 APPENDIX(Nonmandatory Information)X1.RECOMMEN