1、Designation: C 1182 91 (Reapproved 2007)Standard Test Method forDetermining the Particle Size Distribution of Alumina byCentrifugal Photosedimentation1This standard is issued under the fixed designation C 1182; the number immediately following the designation indicates the year oforiginal adoption o
2、r, 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 of
3、 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 met
4、hod to other material.1.3 The values stated in SI units are to be 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 sta
5、ndard 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:C 242 Terminology of Ceramic Whitewares and RelatedProductsE 691 Practice for Conducting an Interlaboratory Study toDetermine
6、the Precision of a Test MethodE 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3. Terminology3.1 Definitions:3.1.1 Refer to Terminology C 242 for definitions of termsused in this test method.4. Summary of Test Method4.1 A homogeneous aqueous dispersion of the powder isprepar
7、ed. 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 specificStok
8、es 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,
9、 the resultsare reported as equivalent diameters (spherical) (Note 2).NOTE 1This diameter in micrometres is referred to as D in theequation:D2518 n H/t!rs2rf!u23 108(1)where:n = viscosity of the fluid, P,H = height of the settling particles, cm,t = time for particle to settle, s,rs= particle density
10、, g/cm3,rf= fluid density, g/cm3, andu = the rotational velocity, cm/s.NOTE 2Refer to Terminology C 242 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 incorporat
11、e 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 sp
12、ecification, quality con-trol, and research and development testing.6. Apparatus6.1 Centrifugal Particle Size Distribution AnalyzerTheanalyzer shall incorporate a centrifuge capable of subjecting ahomogeneous dispersion of the sample to centrifugal accelera-tion in specially designed sample cells. A
13、 collimated beam ofvisible light (either monochromatic or broad-band) shalltraverse the sample cell at a defined distance from the top of the1This test method is under the jurisdiction ofASTM Committee C21 on CeramicWhitewares and Related Products and is the direct responsibility of SubcommitteeC21.
14、04 on Raw Materials.Current edition approved May 1, 2007. Published June 2007. Originallyapproved in 1991. Last previous edition approved in 2001 as C 118291(2001)1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.cell. The change in ph
15、oto 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.) diamete
16、r 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, mercury or alcohol, 0 to 50C, accurate to0.5C.6.7 Sample Cells, as
17、supplied by the instrument manufac-turer.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where
18、 such specifications are available.2Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theprecision of the determination.7.2 Sodium Hexametaphosphate Solution, 0.1 %Tare a50-mL beaker on the balance. Weigh 1.0
19、6 0.1 g of sodiumhexametaphosphate into the beaker. Add 30 to 40 mL ofdistilled or deionized water and dissolve the salt. Pour thesolution into the volumetric flask, rinse the beaker twice withwater, and pour into the flask. Make up the volume to 1000 mLand mix thoroughly. Store in a stoppered glass
20、 or polyethylenereagent bottle labeled with the contents and date of preparation.Discard any solution after six weeks of storage.NOTE 3These reagents are adequate to cover the range of samples upto a maximum diameter of 20 m.8. Procedure8.1 Sample Preparation and Dispersion:8.1.1 Withdraw approximat
21、ely1gofathoroughly mixedpowdered sample (or an equivalent amount of a slurriedsample) and place into a 250-mL beaker. If the sample isreceived in a plastic or glass vial containing about 1 g (60.25g), transfer the entire contents to the 250-mL beaker. Add 200mL of 0.1 % sodium hexametaphosphate solu
22、tion and mix wellby stirring. Disperse by either of the following methods:8.1.1.1 Ultrasonic BathPlace the beaker in the bath withthe bottom of the beaker suspended above the bottom of thebath. In the ideal position, the top of the fluid in the beaker iseven with the liquid level in the bath. Apply
23、ultrasonic energyfor 15 min with frequent stirring. Remove beaker from bath.8.1.1.2 Ultrasonic ProbeInsert the probe into the beakercontaining the sample and apply power for 30 s. Make sure thesample is well suspended during this step. Remove probe fromthe beaker.8.1.2 Add a 25-mm (1-in.) stirring b
24、ar to the beaker andplace on a magnetic stirrer. Stir for approximately 3 min in acold water bath to bring the sample to ambient temperature.Continue stirring at constant temperature.NOTE 4The concentration of the sample may require dilution with0.1 % sodium hexametaphosphate solution to meet the op
25、tical absorbancetolerance specified in the instrument operating manual. Thorough mixingmust accompany any dilution of the sample.8.2 Analyzer Preparation:8.2.1 To warm up the analyzer, apply power a minimum of10 min prior to testing. Conduct the warm-up with the samplecompartment closed. Make certai
26、n that ventilation airflow isnot restricted by adjacent equipment, papers, or other materi-als. Check the printer to ensure a sufficient supply of paper.Clean a pair of sample cells and caps, rinse with the 0.1 %sodium hexametaphosphate solution and store inverted onabsorbent paper.8.2.2 If required
27、 by the manufacturers operating manual,check and adjust the zero and full-scale settings.8.2.3 Input the test parameters (sample and fluid density,fluid viscosity, test range, sedimentation distance, (if required),and centrifuge speed) according to the manufacturers operat-ing manual. Set the fluid
28、viscosity at the value corresponding tothe actual room temperature (see Table 1). Set the range suchthat the volume percent greater than the maximum diameter iscertainly zero and the volume percent finer than the minimumdiameter is less than 10 % (cumulative percent oversize greaterthan 90 %). Preli
29、minary test runs may be required to establishthe range and the size of the divisions needed to accomplishtest limits. The test range and division settings shall provide aminimum of ten divisions within the test range.8.2.4 If required by the manufacturers operating manual,conduct a blank test with c
30、lean dispersant fluid in the sampleand reference cells.8.3 Test Performance:8.3.1 Adjust the rate of the magnetic stirrer to produce aslight vortex in the sample dispersion. With a disposable plasticpipet, withdraw an appropriate volume of sample from thecenter of the dilute dispersion. Make certain
31、 that the dispersionis thoroughly mixed by vigorous pumping with the pipet (avoidsufficient agitation to create bubbles). Completely transfer thewithdrawn sample portion to the drained sample cell. Insert thecell cap, carefully wipe all outer surfaces of the cell, place inthe centrifuge, and start t
32、he test. At the beginning of the test,monitor the absorbance display on the instrument to ensure thatthe initial absorbance is within the specified tolerance. If not,refer to Note 4. When the test is completed, remove the samplecell, clean immediately, and rinse with dispersant fluid.2Reagent Chemic
33、als, 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
34、Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.TABLE 1 Viscosity Coefficients of WaterATemperature, C 20 21 22 23 24 25 26 27 28 29Viscosity coefficient,mPas or cP1.01 0.98 0.96 0.94 0.92 0.89 0.87 0.86 0.84 0.82AViscosity coefficient values to two decimal places have been foun
35、d satisfactoryfor this test method.C 1182 91 (2007)29. Presentation of Data9.1 Analyzer PrintoutThe analyzers that have been foundsuitable for this test method render data printouts that providea permanent record of test conditions and graphic records ofthe size distribution. For many purposes, thes
36、e printouts mayprovide sufficient information.10. Fluid Densities and Viscosity Coefficients10.1 Table 1 lists the viscosity coefficients for water over thetemperature range from 20 to 29C. Use these values for thesodium hexametaphosphate solution. Use a density of 1.00g/mL for these solutions.11. A
37、dditional Data Presentations11.1 The analyzers that have been found suitable for usewith this test method produce a printed report that may includea cumulative size distribution table showing the volumepercent oversize, starting with the programmed maximumdiameter. The incremental divisions are, in
38、some operatingmodes, selectable by the operator, and, in others, determinedby the microcomputer in the instrument.12. Precision and Bias12.1 PrecisionBased on the results of a multilaboratorystudy using the procedures and definitions of PracticesE 691 79 and E 177 80, and over the sample range inclu
39、dedin the study the precision is as follows:12.1.1 RepeatabilityThe within-laboratory repeatability is3.56 % (2s %) of the measured value.12.1.2 ReproducibilityBetween-laboratory reproducibil-ity is 9.92 % (2s %) of the measured value.12.2 BiasSince no absolute method of particle size distri-bution
40、is recognized, it is not possible to discuss the bias of theresults obtained using this test method.13. Keywords13.1 alumina; particle size distribution; photosedimentationASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned
41、in 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 is subject to revision at any time by the responsible technical committee and m
42、ust 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 Headquarters. Your comments will receive careful consideration at a meeting of t
43、heresponsible 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 standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C7
44、00, 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).C 1182 91 (2007)3
