1、Designation:B 430 97(Reapproved 2006)e1Standard Test Method forParticle Size Distribution of Refractory Metal Powders andRelated Compounds by Turbidimetry1This standard is issued under the fixed designation B 430;the number immediately following the designation indicates the year oforiginal adoption
2、 or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTEMultip
3、le source footnotes were removed editorially in May 2006.1.Scope1.1 This test method covers the determination of particlesize distribution of refractory metal powders with a turbidime-ter(1).2Experience has shown that this test method issatisfactory for the analysis of elemental tungsten,molybde-num
4、,rhenium,tantalum metal powders,and tungsten carbidepowders.Other refractory metal powders,for example,el-emental metals,carbides,and nitrides,may be analyzed usingthis test method with caution as to significance until actualsatisfactory experience is developed.The procedure covers thedetermination
5、of particle size distribution of the powder in twoconditions:1.1.1 As the powder is supplied(as-supplied),and1.1.2 After the powder has been de-agglomerated by rodmilling(laboratory milled)according to Practice B 859.1.2 Where dual units are given,inch-pound units are to beregarded as standard.1.3 T
6、his 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
7、.1 ASTM Standards:3B 330 Test Method for Fisher Number of Metal Powdersand Related CompoundsB 821 Guide for Liquid Dispersion of Metal Powders andRelated Compounds for Particle Size AnalysisB 859 Practice for De-Agglomeration of Refractory MetalPowders and Their Compounds Prior to Particle SizeAnaly
8、sisE 456 Terminology Relating to Quality and StatisticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2ASTM Adjunct:4Turbidimeter(6 dwgs)3.Summary of Test Method3.1 A uniform dispersion of the powder in a liquid mediumis allowed to settle in a glas
9、s cell.A beam of light is passedthrough the cell at a level having a known vertical distancefrom the liquid level.The intensity of the light beam isdetermined using a photo cell.This intensity increases withtime as sedimentation of the dispersion takes place.3.2 The times at which all particles of a
10、 given size havesettled below the level of the transmitted light beam arecalculated from Stokes law for the series of sizes chosen forthe particle size analysis.3.3 The intensity of the light beam at these times ismeasured as percent of the light transmitted through the cellwith the clear liquid med
11、ium.The size distribution in thepowder can be calculated from these relative intensities usingthe Lambert-Beer law in the modified form(also see Refs 2,3,4).DW125 dmlog Id12 log Id2!(1)where Id1and Id2are the intensities measured at the timeswhen all particles having diameters larger than d1and d2re
12、spectively have settled below the level of the light beam,dmis the arithmetic mean of particle sizes d1and d2,and DW1-2refers to the relative weight for the particle size range betweend1and d2.Values of DW are determined for each of the particlesize ranges chosen.The sum of these values is(DW.Thewei
13、ght percent of particles in the size range from d1to d2canthen be calculated as:1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.03 on Refractory Metal Powders.Current edition approved Ap
14、ril 1,2006.Published May 2006.Originallyapproved in 1965.Last previous edition approved in 2001 as B 430 97(2001)e1.2The boldface numbers in parenthesis refer to the references listed at the end ofthis test method.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Cust
15、omer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.4Copies of detailed drawings of an acceptable instrument are available fromASTM International Headquarters.Order Adjunct No.ADJB0430.Original adjunctpro
16、duced in 1966.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.Copyright by ASTM Intl(all rights reserved);Thu Apr 16 05:11:32 EDT 2009Downloaded/printed byLaurentian University pursuant to License Agreement.No further reproductions authorized.Weight,%5DW122/(DW!3 100(2)4.Significance and Use4.1 Knowledge of the particle size distribution of refractorymetal powders is useful in predicting powder-processing be-havior,and ultimate perfor
