1、Designation: C958 92 (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
2、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 test method covers the determination of the particlesize distribution of
3、 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 bea
4、m 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 is
5、 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:2C242 Terminology of Ceramic Whiteware
6、s and RelatedProductsE177 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 Te
7、st 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 given se
8、dimenta-tion distance is inversely proportional to the X-ray flux and theequivalent diameter (spherical) is calculated from Stokes law.NOTE 1Refer to Terminology C242. Most equipment manufacturersrefer to this as the equivalent spherical diameter.5. Apparatus5.1 X-Ray Sedimentation Apparatus.5.2 Ult
9、rasonic Probe or BathAn ultrasonic 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 tha
10、tall 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 without less
11、ening 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.7. Hazards7.1 Precautions applying to the use
12、of low-intensity X-raysshould be observed.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. Originallyapprov
13、ed in 1992. Last previous edition approved 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 Su
14、mmary page onthe ASTM website.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., an
15、d the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17.2 Users should be aware that sample concentrations usedin this test me
16、thod may be higher 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 be
17、lieved 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 equivalentamount of a slurried specimen) in
18、to a 50-mL beaker and 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 Dis
19、perse the specimen 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
20、 the beakerand disperse 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
21、an instrument provides 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 distrib
22、ution in the “Percent 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
23、has been achieved.8.8 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 interlaboratory studyof the particle size distribution of alumina and quartz was runin 1989. Nine labor
24、atories participated 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 E691 was followed forthe design and analysis of the data.9.2 Test ResultThe precision information giv
25、en in 9.3 inthe units 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 % reproducibili
26、ty limit(between laboratories)15 % (8 to 29 %) of the test resultThe above terms repeatability limit and reproducibility limitare used as specified in Practice E177. The respective percentcoefficients of variation among test results may be obtained bydividing the above numbers by 2.8.9.4 BiasNo abso
27、lute method of particle size determinationis recognized. Therefore, no justifiable statement can be madeon the bias of the procedure in this test method.10. Keywords10.1 alumina; gravity sedimentation; particle size; particlesize distribution; quartz; sedimentationASTM International takes no positio
28、n respecting the 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.
29、This standard is 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 I
30、nternational Headquarters. 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 sho
31、wn below.This standard 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
32、-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: C21-1004.C958 92 (2014)2
