ASTM_E_2980_-_14.pdf

Designation:E298014Standard Test Methods forEstimating Average Particle Size of Powders Using AirPermeability1This standard is issued under the fixed designation E2980;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods use air permeability to determine anenvelope-specific surface area and its associated averageequivalent spherical diameter(from 0.2 to 75 m)of powders.Two test methods are described:One test method for inorganicmaterials(Test Method 1),and another test method for organicmaterials(Test Method 2).The values obtained are notintended to be absolute but are generally useful on a relativebasis for control purposes.1.2 UnitsWith the exception of the values for density andthe mass used to determine density,for which the use of thegram per cubic centimetre(g/cm3)and gram(g)units is thelongstanding industry practice;and the units for pressure,cmH2Oalso long-standing practice;the values in SI units are tobe regarded as standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2B330 Test Methods for Estimating Average Particle Size ofMetal Powders and Related Compounds Using Air Per-meabilityB859 Practice for De-Agglomeration of Refractory MetalPowders and Their Compounds Prior to Particle SizeAnalysisE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE1638 Terminology Relating to Sieves,Sieving Methods,and Screening MediaE2589 Terminology Relating to Nonsieving Methods ofPowder Characterization2.2 ISO Documents:3ISO 10070 Metallic Powders:Determinations of Envelope-Specific Surface Area from Measurements of the Perme-ability to Air of a Powder Bed Under Steady-State FlowConditions3.Terminology3.1 DefinitionsMany terms used in this test method aredefined in Terminologies E1638 and E2589.3.2 Definitions of Terms Specific to This Standard:3.2.1 air permeability,nmeasurement of air pressure dropacross a packed bed of powder.3.2.2 average particle size,nfor the purposes of these testmethods only,an estimate of the equivalent average sphericalparticle diameter,calculated from the measured envelope-specific surface area,assuming that all the powder particles arespherical and that all are exactly the same size.3.2.3 de-agglomeration,nprocess used to break up ag-glomerates of particles.3.2.4 envelope-specific surface area,nspecific surfacearea of a powder as determined by gas permeametry inaccordance with ISO 10070.3.2.5 HEL Sub-Sieve AutoSizer(HEL SAS),na commer-cially available permeability instrument for measuringenvelope-specific surface area and estimating average particlesize from 0.2 to 75 m.3.2.6 porosity of a bed of powder,nratio of the volume ofthe void space in the powder bed to that of the overall volumeof the powder bed.4.Significance and Use4.1 These test methods provide procedures for determiningthe envelope-specific surface area of powders,from which iscalculated an“average”particle diameter,assuming the par-ticles are monosize,smooth surface,nonporous,sphericalparticles.For this reason,values obtained by these test methods1These test methods are under the jurisdiction of ASTM Committee E29 onParticle and Spray Characterization and is the direct responsibility of SubcommitteeE29.02 on Non-Sieving Methods.Current edition approved Dec.1,2014.Published January 2015.DOI:10.1520/E2980-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 will be reported as an average particle size.The degree ofcorrelation between the results of these test methods and thequality of powders in use will vary with each particularapplication and has not been fully determined.4.2 These test methods are generally applicable to allpowders,including metals(see Test Methods B330 for specificmetal powder requirements),ceramics,and organic materials,for particles having diameters between 0.2 and 75 m.Theyshould not be used for powders composed of particles whoseshape is too far from equiaxed-that is,flakes or fibers.In thesecases,it is permissible to use the test methods described onlyby agreement between the parties concerned.These test met