Designation:F18−12StandardSpecificationandTestMethodforEvaluationofGlass-to-MetalHeadersUsedinElectronDevices1ThisstandardisissuedunderthefixeddesignationF18;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisspecificationandtestmethodcoveracceptancerequirementsforheadersusedinelectrondevicesanddescribesproceduresfordeterminingconformancetotheserequire-ments.1.2Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.1.3Thefollowingsafetyhazardcaveatpertainsonlytothetestmethod(Sections7-13)describedinthisspecification.Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimita-tionspriortouse.2.Terminology2.1DefinitionsofTermsSpecifictoThisStandard:2.1.1Theheadermaybedescribedasanexternalmetalmemberofcylindrical,oval,orothershapeintowhichissealedoneormorewireleadsormetaltubulationsthroughaglassmedium.Themetalpartsmaybeplatedorunplatedandtheglassmaybeclearoropaque.3.SignificanceandUse3.1Thisstandardcoversproceduresforconductingme-chanicalandvacuumleaktestsonglass-to-metalheadersandissuitableforqualitycontrolandresearchanddevelopmentuse.3.2Thisstandardissuitableforassessingboththequalityofmaterialsaswellasthemanufacturingtechniquesused.4.AcceptanceRequirements4.1Theheadersshallconformtotherequirementsasspecifiedin4.1.1and4.1.2whentestedinaccordancewiththeprescribedmethodsoftest(Sections5-13).4.1.1Visual:4.1.1.1Cracksaroundtheleadshallberestrictedaxiallyandradiallytooneleaddiameter.Specimensshowinganyothertypeofcrackshallberejected.4.1.1.2Theglassshallbefreeofinclusion...
