ASTM_B_480_-_88_2017.pdf

Designation:B48088(Reapproved 2017)Standard Guide forPreparation of Magnesium and Magnesium Alloys forElectroplating1This standard is issued under the fixed designation B480;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 guide describes two processes used for plating onmagnesium and magnesium alloys:direct electroless nickelplating and zinc immersion.Some users report that the directelectroless nickel procedure does not produce quite as high alevel of adhesion as zinc immersion.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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.For specific hazardstatements,see 5.1.1 and 5.2.9.2.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2B322 Guide for Cleaning Metals Prior to Electroplating3.Significance and Use3.1 Metals are electroplated on magnesium for variouspurposes:solderability,RF grounding,hermetic sealing,wearresistance,corrosion resistance,appearance,and electricalconductivity,for example.Because magnesium is covered witha naturally occurring oxide film,usual procedures for thepreparation of metals for autocatalytic or electrolytic platingcannot be used.4.Reagents4.1 Purity of ReagentsAll acids and chemicals used in thisguide are of technical grade.Acid and base solutions are basedon the following assay materials:Ammonium hydroxide(NH4OH)30 mass%,density 0.895 g/LNitric acid(HNO3)67 mass%,density 1.16 g/LSulfuric acid(H2SO4)93 mass%,density 1.40 g/LHydrofluoric acid(HF)70 mass%,density 1.258 g/LPhosphoric acid(H3PO4)85 mass%,density 1.689 g/L4.2 Purity of WaterAll water used for solutions,whethernew or recycled,should be monitored for cations,anions,andorganic matter that are known to interfere with the platingprocess.5.Processes5.1 Procedures:5.1.1 Wheel polish and buff parts for smooth,highly pol-ished surfaces.Tumble and burnish small parts.Acid pickle theparts after use of wire brushing or steel wool.(WarningBecause of the high flammability of powdered magnesium,special precautions against fire are important.Polishing andbuffing lathes should be kept scrupulously clean.Dust fromgrinding in and around lathes should be swept up and placed inclosed containers for proper disposal.Exhaust systems shouldbe cleaned frequently and the residues handled similarly.Ifabrasives are used in tumble finishing,similar precautionarytechniques should be used for the solids from the abrasiveslurry.)5.1.2 ChemicalRemove oil and grease in an alkaline soakcleaner.Remove other soils and coatings in suitable acidpickling solutions.NOTE1General information on the cleaning of metals is given inPractice B322.5.2 General Electroplating Procedure:5.2.1 Remove oil,grease,and other soils left from preplat-ing procedures by soak cleaning in an alkaline cleaner suitablefor magnesium.5.2.2 Rinse in cold water.1This guide is under the jurisdiction of ASTM Committee B08 on Metallic andInorganic Coatings and is the direct responsibility of Subcommittee B08.02 on PreTreatment.Current edition approved May 1,2017.Published May 2017.Originallyapproved in 1968.Last previous edition approved in 2010 as B480 88(2010).DOI:10.1520/B0480-88R17.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 NOTE2As generally used in rinsing terminology,cold water refers towater from an unheated water supply as opposed to heated water used fordrying or other purposes.In some areas,particularly in water,ambientwater temperatures may be too low for effective rinsing.In thoseinstances,the rinse water may need to be heated.A minimum temperatureof 16C is recommen