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【英文标准名称】:StandardPracticeforDe-AgglomerationofRefractoryMetalPowdersandTheirCompoundsPriortoParticleSizeAnalysis
【原文标准名称】:粒径分析前耐熔金属粉末及其化合物去除结块的标准实施规程
【标准号】:ASTMB859-2003(2008)e1
【标准状态】:现行
【国别】:美国
【发布日期】:2003
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:B09.03
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:de-agglomeration;laboratory-milled;laboratorymilling;molybdenum;particlesizeanalysis;powders;refractorymetals;rhenium;rod-milled;rodmilling;tantalum;tungsten;tungstencarbide;De-agglomeration;Laboratory-milledpowders;Molybd
【摘要】:Refractorymetalpowders,suchastungstenandmolybdenum,areusuallyproducedbyhydrogenreductionathightemperatures.Thus,theyusuallycontainnumerouslarge,strongly-sinteredagglomerates.Manyofthemanufacturingprocessesusingthesepowdersinvolveamillingsteporsomesimilartreatmentordependontheindividualparticulatesize,notontheagglomeratesize.Thus,aknowledgeoftheindividualparticulatesizedistribution,nottheagglomeratesizedistribution,isusuallydesiredfromaparticlesizeanalysisofthesepowders.Thispracticeprovidesaprocedureforbreakingdownagglomeratesintotheirconstituentparticles(de-agglomeration),withoutexcessivefractureoftheindividualparticles.Theprocedureisoftenreferredtoaslaboratorymillingorrodmilling.Thelaboratorymillingconditionsspecifiedinthisguidehavebeeninusesince1965aspartofTestMethodB430.Thisguidewasfirstpublishedasaseparate,stand-alonestandardin1995becauseofitsapplicabilityinpreparingpowdersamplesforanalysisbyothermethods(forexample,TestMethodsB761andB822),inadditiontoTestMethodB430.Informationonthedevelopmentandestablishmentofthemillingconditionsherespecifiedcanbefoundinthefootnotedreference.Themillingproceduredescribedinthispracticedoesnotnecessarilybreakdownonlyagglomerateswithoutfracturingindividualparticles;someparticlefracturemayoccurincertainpowders.However,useofthispracticedoesprovideconsistentparticlesizeanalysisresultsthathavebeenfoundtorelatewelltopowderbehaviorinnumerousmanufacturingprocesses.Thispracticeshallbeusedforthede-agglomerationoftherefractorymetalpowdersandcompoundslistedin1.1,whenanevaluationoftheindividualparticulatesizedistributionisrequiredfromthesubsequentparticlesizeanalysis.Itshallnotbeusedwhentheagglomerate(as-isoras-supplied)sizedistributionisdesired.ThispracticemaybeusedinpreparingsamplesforTestMethodsB330,B430,B761,B822,andotherparticlesizeanalysismethods,priortothedispersionprocedureofGuideB821,ifused.1.1Thispracticecoversthede-agglomerationofrefractorymetalpowdersandtheircompoundsinpreparationforparticlesizeanalysis.1.2Experiencehasshownthatthispracticeissatisfactoryforthede-agglomerationofelementaltungsten,molybdenum,rhenium,andtantalummetalpowders,andtungstencarbide.Othermetalpowders(forexample,elementalmetals,carbides,andnitrides)maybepreparedforparticlesizeanalysisusingthispracticewithcautionastoeffectivenessuntilactualsatisfactoryexperienceisdeveloped.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.Forspecificprecautionarystatements,seeNote2.
【中国标准分类号】:H16
【国际标准分类号】:
【页数】:3P.;A4
【正文语种】:英语