1、Designation: C 958 92 (Reapproved 2007)Standard Test Method forParticle Size Distribution of Alumina or Quartz by X-RayMonitoring of Gravity Sedimentation1This standard is issued under the fixed designation C 958; the number immediately following the designation indicates the year oforiginal adoptio
2、n 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.1. Scope1.1 This test method covers the determination of the particlesize distribution
3、 of alumina or 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
4、beam that is passed 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
5、 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. For specific hazardstatements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2C 242 Terminology of Ceramic White
6、wares and RelatedProductsE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 691 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 C 242.4. Summar
7、y of Test Method4.1 An aqueous 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 g
8、iven sedimenta-tion distance is inversely proportional to the X-ray flux and theequivalent diameter (spherical) is calculated from Stokes law.NOTE 1Refer to Terminology C 242. Most equipment manufacturersrefer to this as the equivalent spherical diameter.5. Apparatus5.1 X-Ray Sedimentation Apparatus
9、.5.2 Ultrasonic Probe or BathAn ultrasonic probe ap-proximately 13-mm (12-in.) in diameter and approximately 50to 100 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 inte
10、nded thatall reagents shall conform to the 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 with
11、out lessening theaccuracy of the determination.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.1This test method is under the jurisdi
12、ction ofASTM Committee C21 on CeramicWhitewares and Related Products and is the direct responsibility of SubcommitteeC21.04 on Raw Materials.Current edition approved May 1, 2007. Published June 2007. Originallyapproved in 1992. Last previous edition approved in 2000 as C 95892(2000)2For referenced A
13、STM 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, American Chemical Society Specifications, AmericanChemical
14、 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. Pharmaceutical Convention, Inc. (USPC), Rockvil
15、le,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Hazards7.1 Precautions applying to the use of low-intensity X-raysshould be observed.7.2 Users should be aware that sample concentrations usedin this test method may be higher
16、than those considered idealby some authorities and 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 signif
17、icant.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 equivalentamount of a slurried specimen) into a 50-mL beaker a
18、nd add 30mL of the dispersing liquid. Mix well using a rubber policemanto break up any clumping.8.3.1 The amount of specimen required may vary betweeninstruments. Adjust the specimen weight to reduce the X-rayintensity according to the manufacturers recommended con-ditions.8.4 Disperse the specimen
19、using either of the instrumentsgiven in 8.4.1 and 8.4.2:8.4.1 Ultrasonic BathPlace the beaker in the bath anddisperse the specimen for 5 min with frequent stirring. It isbeneficial to cause the liquid level in the bath and beaker tomatch.8.4.2 Ultrasonic ProbeInsert the probe into the beakerand disp
20、erse the specimen for 1 min. Do not allow thetemperature of the dispersion liquid to rise more than 2C.8.5 Add a 25-mm (1-in.) magnetic stirring bar to the beaker,and place the beaker in the instruments cell compartment.Adjust the stirring rate to produce a slight vortex.8.5.1 If an instrument provi
21、des a different method forstirring and circulating the dispersion, be sure to follow theappropriate procedure.8.6 Fill the cell with the dispersed slurry according to themanufacturers instructions, making sure that no air bubblesremain in the cell.8.7 Run the particle size distribution in the “Perce
22、nt FinerThan” mode using a starting diameter of 50 m. Calculate theinstrument rates using a density of 3.95 g/m3for alumina and2.65 g/m3for silica.8.7.1 It is recommended that 8.6 and 8.7 be repeated inorder to increase confidence in the analysis and to ensure thatgood dispersion has been achieved.8
23、.8 Upon completion of the analyses, rinse or clean theinstrument for the following run as suggested by the manufac-turer.9. Precision and Bias49.1 Interlaboratory Test ProgramAn interlaboratorystudy of the particle size distribution of alumina and quartz wasrun in 1989. Nine laboratories participate
24、d in the study, whichincluded three different models of instruments, with eachlaboratory testing five specimens of each material. Except forthe use of only two materials, Practice E 691 was followed forthe design and analysis of the data.9.2 Test ResultThe precision information given in 9.3 inthe un
25、its of equivalent spherical diameter (in micrometres) isfor the comparison of two test results, each of which is theaverage of five test determinations.9.3 Precision:Test range 1 to 50 m95 % repeatability limit(within laboratory)10 % (5 to 21 %) of the test result95 % reproducibility limit(between l
26、aboratories)15 % (8 to 29 %) of the test resultThe above terms repeatability limit and reproducibility limitare used as specified in Practice E 177. The respective percentcoefficients of variation among test results may be obtained bydividing the above numbers by 2.8.9.4 BiasNo absolute method of pa
27、rticle size determina-tion is recognized. Therefore, no justifiable statement can bemade on the bias of the procedure in this test method.10. Keywords10.1 alumina; gravity sedimentation; particle size; particlesize distribution; quartz; sedimentationASTM International takes no position respecting th
28、e validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard i
29、s subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International He
30、adquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This s
31、tandard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: C21-1004.C 958 92 (2007)2
