Designation:D4926−20StandardTestMethodforGammaAluminaContentinCatalystsandCatalystCarriersContainingSilicaandAluminabyX-rayPowderDiffraction1ThisstandardisissuedunderthefixeddesignationD4926;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofgammaaluminaandrelatedtransitionaluminasincatalystsandcata-lystcarrierscontainingsilicaandaluminabyX-raypowderdiffraction,usingthediffractedintensityofthepeakoccurringatabout67°2θwhencopperKαradiationisemployed.1.2Units—ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.4Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2E691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethod3.SummaryofTestMethod3.1Asampleofcatalystorcatalystcarrieriscalcinedandground,andanX-raypowderdiffractionpatternisobtainedunderspecifiedconditionsovertheapproximaterangefrom52to76°2θ.Thediffractedintensityabovebackgroundforthepeakoccurringatabout67°2θiscomparedtothatofareferencesample,afterappropriateadjustmentsaremadeforscalesettingsandpeakhalf-widths.4.SignificanceandUse4.1Thistestmethodisforestimatingtherelativeamountofgammaaluminaincalcinedcatalystorcatalystcarriersamples,assumingthattheX-raypowder...
