Designation:B920−16StandardPracticeforPorosityinGoldandPalladiumAlloyCoatingsonMetalSubstratesbyVaporsofSodiumHypochloriteSolution1ThisstandardisissuedunderthefixeddesignationB920;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestpracticecoversequipmentandmethodsforrevealingtheporosityofgoldandpalladiumcoatings,particu-larlyelectrodepositsandcladmetalsusedonelectricalcon-tacts.1.2Thistestpracticeissuitableforcoatingscontaininggoldor75%bymassofpalladiumonsubstratesofcopper,nickel,andtheiralloys,whicharecommonlyusedinelectricalcontacts.1.3Avarietyoffullporositytestingmethodsisdescribedintheliterature.2,3TheseporosityTestMethodsareB735,B741,B798,B799,andB809.AnASTMGuidetotheselectionofporositytestsforelectrodepositsandrelatedmetalliccoatingsisavailableasGuideB765.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Thevaluesgiveninparenthesesareforinformationonly.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.Forspecifichazards,seeSection6.2.ReferencedDocuments2.1ASTMStandards:4B374TerminologyRelatingtoElectroplatingB542TerminologyRelatingtoElectricalContactsandTheirUseB735TestMethodforPorosityinGoldCoatingsonMetalSubstratesbyNitricAcidVaporB741TestMethodforPorosityInGoldCoatingsOnMetalSubstratesByPaperElectrography(Withdrawn2005)5B765GuideforSelectionofPorosityandGrossDefectTestsforElectrodepositsandRelatedMetallicCoatingsB798TestMethodforPorosityinGoldorPalladiumCoat-ingsonMetalSubstratesbyGel-BulkElectrographyB799TestMethodforPorosityinGoldandPalladiumCoatingsbySulfurousAcid/Sulfur-DioxideVaporB809TestMethodforPorosityinMetallicCoatingsbyHumidSulfurV...
