1、Designation:C95892(Reapproved 2014)Standard Test Method forParticle Size Distribution of Alumina or Quartz by X-RayMonitoring of Gravity Sedimentation1This standard is issued under the fixed designation C958;the number immediately following the designation indicates the year oforiginal adoption or,i
2、n 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 test method covers the determination of the particlesize distribution of alumina or
3、 quartz powders in the rangefrom 0.5 to 50 m and having a median particle diameter from2.5 to 10 m using a sedimentation method.This test methodis one of several found valuable for the measurement ofparticle size.Instruments used for this test method employ aconstant intensity X-ray beam that is pas
4、sed through a sedi-menting dispersion of particles.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibilit
5、y 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.For specific hazardstatements,see Section 7.2.Referenced Documents2.1 ASTM Standards:2C242 Terminology of Ceramic Whitewares and RelatedProduct
6、sE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 For definitions of terms used in this test method,refer toTerminology C242.4.Summary of Test Method4.1 An aqueous
7、 homogeneous dispersion of the specimen ispermitted to settle in a cell.The decrease in particle concen-tration over a programmed settling distance is monitored by anX-ray beam passing through the sedimenting dispersion to adetector.The specimen concentration at any given sedimenta-tion distance is
8、inversely proportional to the X-ray flux and theequivalent diameter(spherical)is calculated from Stokes law.NOTE1Refer to Terminology C242.Most equipment manufacturersrefer to this as the equivalent spherical diameter.5.Apparatus5.1 X-Ray Sedimentation Apparatus.5.2 Ultrasonic Probe or BathAn ultras
9、onic probe approxi-mately 13-mm(12-in.)in diameter and approximately 50 to100 W or an ultrasonic bath of approximately 0.3 W/cm2(2W/in.2).6.Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the
10、specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determinati
11、on.6.2 Distilled or Deionized Water.6.3 Dispersing LiquidDissolve 1.0 g/L of reagent gradesodium hexametaphosphate in distilled or deionized water.Discard any remaining solution after six weeks from date ofpreparation.7.Hazards7.1 Precautions applying to the use of low-intensity X-raysshould be obse
12、rved.1This test method is under the jurisdiction ofASTM Committee C21 on CeramicWhitewares and Related Productsand is the direct responsibility of SubcommitteeC21.04 on Raw Materials.Current edition approved Jan.1,2014.Published February 2014.Originallyapproved in 1992.Last previous edition approved
13、 in 2007 as C95892(2007)DOI:10.1520/C0958-92R14.2For 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.3Reagent Chemicals
14、,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.
15、Pharmaceutical Convention,Inc.(USPC),Rockville,MD.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.2 Users should be aware that sample concentrations usedin this test method may be higher than those considered idealby some authorities an
16、d that the range of this test methodextends into the region where Brownian motion could be afactor in conventional gravity sedimentation.Within the rangeof this test method neither the sample concentration norBrownian motion are believed to be significant.8.Procedure8.1 Prepare the instrument for use according to the manu-facturers instructions.8.2 If necessary,manually zero the instrument with the cellfilled with the dispersing liquid.8.3 Transfer 2.5 g of the dry specimen(or an equivalentamoun
