ASTM_C_1182_-_09_2014.pdf

Designation:C118209(Reapproved 2014)Standard Test Method forDetermining the Particle Size Distribution of Alumina byCentrifugal Photosedimentation1This standard is issued under the fixed designation C1182;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.Scope*1.1 This test method covers the determination of the particlesize distribution of alumina in the range from 0.1 to 20 mhaving a median particle diameter from 0.5 to 5.0 m.1.2 The procedure described in this test method may besuccessfully applied to other ceramic powders in this generalsize range.It is the responsibility of the user to determine theapplicability of this test method to other material.1.3 The values stated in SI units are to regarded as thestandard.The values given in parentheses are for informationonly.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:2C242 Terminology of Ceramic Whitewares and RelatedProductsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3.Terminology3.1 Definitions:3.1.1 Refer to Terminology C242 for definitions of termsused in this test method.4.Summary of Test Method4.1 A homogeneous aqueous dispersion of the powder isprepared.While kept in a thoroughly mixed condition,a smallaliquot is transferred to the analyzer sample cell,which isplaced in the instrument and subjected to a controlled centrifu-gal acceleration at a known or controlled temperature.Atpredetermined times related to the sedimentation of specificStokes diameters(Note 1),the optical absorbance is recordedand ratioed to the initial value to determine the fraction of thetotal sample that has sedimented a specific distance.A volumebased size distribution is calculated from the absorbance-timedata.Since alumina particles are not truly spherical,the resultsare reported as equivalent diameters(spherical)(Note 2).NOTE1This diameter in micrometres is referred to as D in theequation:D2518 nH/t!s2 f!u23108(1)where:n=viscosity of the fluid,P,H=height of the settling particles,cm,t=time for particle to settle,s,s=particle density,g/cm3,f=fluid density,g/cm3,andu=the rotational velocity,cm/s.NOTE2Refer to Terminology C242 for the ASTM definition of thisterm.Most equipment manufacturers refer to this as the equivalentspherical diameter.4.2 The instruments that have been found suitable for thistest method incorporate microcomputers that control instru-ment operation and perform all required data acquisition andcomputation functions.5.Significance and Use5.1 Manufacturers and users of alumina powders will findthis test method useful to determine the particle size distribu-tion of these materials for product specification,qualitycontrol,and research and development testing.6.Apparatus6.1 Centrifugal Particle Size Distribution AnalyzerTheanalyzer shall incorporate a centrifuge capable of subjecting a1This test method is under the jurisdiction ofASTM Committee C21 on CeramicWhitewares and Related Products and is the direct responsibility of SubcommitteeC21.04 on Raw Materials.Current edition approved Dec.1,2014.Published December 2014.Originallyapproved in 1991.Last previous edition approved in 2009 as C1182 09.DOI:10.1520/C1182-09R14.2For 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 homogeneous dispersion of the sample to centrifugal accelera-tion in specially designed sample cells.A collimated beam ofvisible light(either monochromatic or broad-band)shall tra-verse the sample cell at a defined distance from the top of thecell.The change in photo extinction resulting from sedimen-tation of the sample shall be measured by a photo detector andappropriate electronic circuits,and used to calculate thevolume-based sized distribution of the sample.6.2 Ultrasonic Probe,consisting of power unit,ultrasonictransducer,and 13-mm(12-in.)diameter probe,200 to 250 W.6.3 Ultrasonic Water Bath,power density approximately 0.3W/cm2(2 W/in.2).6.4 Balance,top-loading,accurate to 60.1 g.6.5 Stirrer,magnetic,with 25-mm(1-in.)and 19-mm(34-in.)stirring bars.6.6 Thermometer,0 to 50C,accurate to 0.5C.May also bean ele