ASTM_B_821_-_10_2016.pdf

Designation:B82110(Reapproved 2016)Standard Guide forLiquid Dispersion of Metal Powders and RelatedCompounds for Particle Size Analysis1This standard is issued under the fixed designation B821;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 This guide covers the dispersion in liquids of metalpowders and related compounds for subsequent use in particlesize analysis instruments.This guide describes a generalprocedure for achieving and determining dispersion;it alsolists procedures that are currently in general use for certainmaterials.1.2 This guide is limited to metal powders and related metalcompounds.However,the general procedure described hereinmay be used,with caution as to its significance,for otherparticulate materials,such as ceramics,pigments,minerals,etc.1.3 The values stated in inch-pound units are to be regardedas the standard.The values given in parentheses are forinformation only.1.4 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:2B243 Terminology of Powder MetallurgyB430 Test Method for Particle Size Distribution of Refrac-tory Metal Powders and Related Compounds by Turbidi-metryB761 Test Method for Particle Size Distribution of MetalPowders and Related Compounds by X-Ray Monitoringof Gravity SedimentationB822 Test Method for Particle Size Distribution of MetalPowders and Related Compounds by Light Scattering3.Terminology3.1 DefinitionsDefinitions of powder metallurgy termscan be found in Terminology B243.4.Significance and Use4.1 The method of powder dispersion in a liquid has asignificant effect on the results of a particle size distributionanalysis.The analysis will show a too-coarse,unstable,ornonrepeatable distribution if the powder has not been dispersedadequately.It is therefore important that parties wishing tocompare their analyses use the same dispersion technique.4.2 This guide provides established powder dispersion tech-niques for certain materials and the means of deriving tech-niques for materials not listed.It should be used by all partiesperforming liquid-dispersed particle size analysis of all of thematerials covered by this guide(see 1.1,1.2,and 4.1).4.3 This guide should be used in the preparation of powdersfor use in Test Methods B430,B761,and B822 and otherprocedures that analyze metal powder particle size distribu-tions in liquid-dispersed systems.5.Apparatus5.1 Microscope,suitable for observation of particles in thesize range of 5 to 1000 m.5.2 Ultrasonic Probe,12-in.(25.4-mm)tip,with the powerlevel to be determined by this guide.5.3 Ultrasonic BathPower level to be determined by thisguide.6.Reagents6.1 Purity of ReagentsReagent grade chemicals should beused in all tests.Unless otherwise indicated,it is intended thatall reagents should conform to the specifications of theCommittee on Analytical Reagents of the American Chemical1This guide is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.02 on Base Metal Powders.Current edition approved Oct.1,2016.Published October 2016.Originallyapproved in 1992.Last previous edition approved 2010 as B821 10.DOI:10.1520/B0821-10R16.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 Society.3Other grades may be used,provided it is firstascertained that the reagent is of sufficiently high purity topermit its use without lessening the accuracy of the determi-nation.6.2 SurfactantsSuggested surfactants are listed in Table 1and footnotes 4 through 6.4,5,67.General Dispersion Procedure7.1 The general procedure for determining and achievingproper dispersion is outlined in Fig.17and described in detailbelow:7.1.1 Place a test portion of the powder to be analyzed in abeaker containing the carrier liquid,selected according to7.1.2.3Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockvill