Designation:F44−95(Reapproved2011)StandardSpecificationforMetallizedSurfacesonCeramic1ThisstandardisissuedunderthefixeddesignationF44;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisspecificationcoversrequirementsforpowderedrefractorymetalcoatingsproducedwithorwithoutadditives.Thesecoatingsareappliedtoceramicbodiesinordertojoinceramicbodiestometalsortoothermetallizedceramicsbymeansofbrazingorsoldering.Includedinthisspecificationarerequirementsforasecondarymetalliclayerwhichisusuallyappliedovertherefractorymetallayer.1.2Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.1.3Thevaluesstatedininch-poundunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.2.ReferencedDocuments2.1ASTMStandards:2E3GuideforPreparationofMetallographicSpecimensF19TestMethodforTensionandVacuumTestingMetal-lizedCeramicSeals3.Terminology3.1DefinitionsofTermsSpecifictoThisStandard:3.1.1ceramics—asreferredtointhisspecificationareunderstoodtobeinorganic,nonmetallicmaterials,themajorphaseofwhichmustbecrystalline.Aglassyintercrystallinematrixmaybepresentasoneoftheminorphases.3.1.2metallizing—onaceramic,isaprocesswherebyasinteredmatrixofmetalparticlesfirmlyadherestotheceramic.3.1.3refractorymetals—thosemetalswithmeltingpointsequaltoorhigherthanthatofchromium.Therefore,thisgroupincludeschromium,columbium,molybdenum,rhenium,tanta-lum,andtungsten.4.OrderingInformation4.1Themanufacturerandpurchasershallagreeuponspe-cificqualitylevelsasoutlinedinthefollowingsections:4.1.1Uniformityofmetallizing(Section5),4.1.2Thicknessofmetallizing(Section6),4.1.3Secondarymetallayeronthemetallizing(Section9),4.1.4Valuesforbondstrength(Secti...
