1、Designation: C1182 09 (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,
2、 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 a
3、lumina 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 metho
4、d 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
5、 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 Pr
6、ecision 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. Whil
7、e 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 diame
8、ters (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 res
9、ultsare reported as equivalent diameters (spherical) (Note 2).NOTE 1This diameter in micrometres is referred to as D in theequation:D2518 n H/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=
10、fluid density, g/cm3, andu = the rotational velocity, cm/s.NOTE 2Refer 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 microcomput
11、ers 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,
12、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
13、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, o
14、rcontact 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, W
15、est Conshohocken, PA 19428-2959. United States1homogeneous 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. T
16、he 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 (
17、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 electronic
18、 temperature measuring device, properlycalibrated, that meets the given specifications.6.7 Sample Cells, as 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 c
19、onform 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 lessening theprecision of
20、 the determination.7.2 Sodium Hexametaphosphate Solution , 0.1 %Tare a50-mL beaker on the balance. Weigh 1.0 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 wi
21、thwater, and pour into the flask. Make up the volume to 1000 mLand mix thoroughly. Store in a stoppered glass 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 sample
22、s upto a maximum diameter of 20 m.8. Procedure8.1 Sample Preparation and Dispersion :8.1.1 Withdraw approximately1gofathoroughly 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
23、 (60.25g), transfer the entire contents to the 250-mL beaker. Add 200mL of 0.1 % sodium hexametaphosphate solution 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 theba
24、th. In the ideal position, the top of the fluid in the beaker iseven with the liquid level in the bath. Apply 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
25、thesample is well suspended during this step. Remove probe fromthe beaker.8.1.2 Add a 25-mm (1-in.) stirring bar 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 4T
26、he concentration of the sample may require dilution with0.1 % sodium hexametaphosphate solution to meet the optical 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
27、 power a minimum of10 min prior to testing. Conduct the warm-up with the samplecompartment closed. Make certain 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
28、, rinse with the 0.1 %sodium hexametaphosphate solution and store inverted onabsorbent paper.8.2.2 If required 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
29、distance, (if required),and centrifuge speed) according to the manufacturers operat-ing manual. Set the fluid 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
30、percent finer than the minimumdiameter is less than 10 % (cumulative percent oversize greaterthan 90 %). Preliminary 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 divis
31、ions within the test range.8.2.4 If required by the manufacturers operating manual,conduct a blank test with clean 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 disposabl
32、e plasticpipet, withdraw an appropriate volume of sample from thecenter of the dilute dispersion. Make certain that the dispersionis thoroughly mixed by vigorous pumping with the pipet (avoid3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For s
33、uggestions 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), Rockville,MD.TABLE 1 Viscosity Coeffic
34、ients 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 found satisfactoryfor this test method.C1182 09 (2014)2sufficient agitation to create bubbles). Co
35、mpletely 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 the test. At the beginning of the test,monitor the absorbance display on the instrument to ensure thatthe initial absorbance
36、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.9. Presentation of Data9.1 Analyzer PrintoutThe analyzers that have been foundsuitable for this test method render data printouts that prov
37、idea permanent record of test conditions and graphic records ofthe size distribution. For many purposes, these 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. U
38、se these values for thesodium hexametaphosphate solution. Use a density of 1.00g/mL for these solutions.11. Additional 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
39、 the volumepercent oversize, starting with the programmed maximumdiameter. The incremental divisions are, in 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 multilaboratory
40、study using the procedures and definitions of PracticesE691 79 and E177 80, and over the sample range includedin 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 reproducibilit
41、yis 9.92 % (2s %) of the measured value.12.2 BiasSince no absolute method of particle size distri-bution is recognized, it is not possible to discuss the bias of theresults obtained using this test method.13. Keywords13.1 alumina; particle size distribution; photosedimentationSUMMARY OF CHANGESCommi
42、ttee C21 has identified the location of selected changes to this standard since the last issue(C118291(2007) that may impact the use of this standard.(1) 1.3 was updated(2) Revision of 6.6 to remove reference to a mercurythermometer, and to allow the use of an electronic temperaturemeasuring device.
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