Designation:F144−80(Reapproved2015)StandardPracticeforMakingReferenceGlass-MetalSandwichSealandTestingforExpansionCharacteristicsbyPolarimetricMethods1ThisstandardisissuedunderthefixeddesignationF144;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversthepreparationandtestingofareferenceglass-metalsandwichsealfordeterminingstressintheglassorfordeterminingthedegreeofthermalexpansion(orcontraction)mismatchbetweentheglassandmetal.TestsareinaccordancewithTestMethodF218(Section2).1.2Thispracticeappliestoallglassandmetal(oralloy)combinationsnormallysealedtogetherintheproductionofelectroniccomponents.1.3Thepracticallimitofthetestinderivingmismatchisapproximately300ppm,abovewhichtheglassislikelytofracture.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyproblems,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2F15SpecificationforIron-Nickel-CobaltSealingAlloyF30SpecificationforIron-NickelSealingAlloysF31SpecificationforNickel-Chromium-IronSealingAlloysF47TestMethodforCrystallographicPerfectionofSiliconbyPreferentialEtchTechniques(Withdrawn1998)3F79SpecificationforType101SealingGlassF105SpecificationforType58BorosilicateSealingGlassF218TestMethodforMeasuringOpticalRetardationandAnalyzingStressinGlassF256SpecificationforChromium-IronSealingAlloyswith18or28PercentChromium3.SummaryofPractice3.1Sealsofastandardconfigurationarepreparedfromrepresentativespecimensoftheglassandmetaltobetested.Theglassandmetalarecleaned,treated,andsizedtospecifiedproportions.Plane-interfacedsealsareformed,annealed,andmeasuredforresidualopticalretardation.Thestressparalleltotheinterfaceineachsealis...
