1、Designation: B822 10Standard Test Method forParticle Size Distribution of Metal Powders and RelatedCompounds by Light Scattering1This standard is issued under the fixed designation B822; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, 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 by light scattering, repor
3、ted as volume per-cent, of particulate materials including metals and compounds.1.2 This test method applies to analyses with both aqueousand nonaqueous dispersions. In addition, analysis can beperformed with a gaseous dispersion for materials that arehygroscopic or react with a liquid carrier.1.3 T
4、his test method is applicable to the measurement ofparticulate materials in the range of 0.4 to 2000 m, or a subsetof that range, as applicable to the particle size distributionbeing measured.1.4 The values stated in SI units are to be regarded as thestandard.1.5 This standard does not purport to ad
5、dress 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:2B215 Practic
6、es for Sampling Metal PowdersB243 Terminology of Powder MetallurgyB821 Guide for Liquid Dispersion of Metal Powders andRelated Compounds for Particle Size AnalysisE1617 Practice for Reporting Particle Size CharacterizationData2.2 ISO Standard:3ISO13320-1 Particle Size AnalysisLaser DiffractionMethod
7、sPart 1: General Principles3. Terminology3.1 DefinitionsDefinitions of powder metallurgy termscan be found in Terminology B243.3.2 Definitions of Terms Specific to This Standard:3.2.1 backgroundextraneous scattering of light by ele-ments other than the particles to be measured; includesscattering by
8、 contamination in the measurement path.3.2.2 Fraunhofer Diffractionthe optical theory that de-scribes the low-angle scattering of light by particles that arelarge compared to the wavelength of the incident light.43.2.3 Mie Scatteringthe complex electromagnetic theorythat describes the scattering of
9、light by spherical particles. It isusually applied to particles with diameters that are close to thewavelength of the incident light. The real and imaginaryindices of light refraction of the particles are needed.43.2.4 multiple scatteringthe rescattering of light by aparticle in the path of light sc
10、attered by another particle. Thisusually occurs in heavy concentrations of a particle dispersion.4. Summary of Test Method4.1 Aprepared sample of particulate material is dispersed inwater, or a compatible organic liquid, and circulated throughthe path of a light beam or some other suitable light sou
11、rce. Adry sample may be aspirated through the light in a carrier gas.The particles pass through the light beam and scatter it.Photodetector arrays collect the scattered light that is convertedto electrical signals, which are then analyzed in a micropro-cessor. The signal is converted to a size distr
12、ibution usingFraunhofer Diffraction or Mie Scattering, or a combination ofboth. Scattering information is analyzed assuming a sphericalmodel. Calculated particle sizes are therefore presented asequivalent spherical diameters.Additional information pertain-ing to the general principles of particle si
13、ze distributionanalysis by light scattering can be found in ISO Standard13320-1.5. Significance and Use5.1 Reported particle size measurement is a function of boththe actual particle dimension and shape factor as well as the1This test method is under the jurisdiction of ASTM Committee B09 on MetalPo
14、wders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.02 on Base Metal Powders.Current edition approved May 1, 2010. Published June 2010. Originallypublished as B822 92. Last previous edition B822 02. DOI: 10.1520/B0822-10.2For referenced ASTM standards, visit the AST
15、M 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.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036
16、, http:/www.ansi.org.4Muly, E. C., Frock, H. N., “Industrial Particle Size Measurement Using LightScattering,” Optical Engineering, Vol 19, No 6, 1980, pp. 861869.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West
17、 Conshohocken, PA 19428-2959, United States.particular physical or chemical properties being measured.Caution is required when comparing data from instrumentsoperating on different physical or chemical parameters or withdifferent particle size measurement ranges. Sample acquisition,handling, and pre
18、paration can also affect reported particle sizeresults.5.1.1 It is important to recognize that the results obtained bythis test method, or any other method for particle size deter-mination using different physical principles, may disagree. Theresults are strongly influenced by the physical principle
19、semployed by each method of particle size analysis. The resultsof any particle sizing method should be used only in a relativesense; they should not be regarded as absolute when comparingresults obtained by other methods.5.2 Light scattering theory has been available for manyyears for use in the det
20、ermination of particle size. Severalmanufacturers of testing equipment now have units based onthese principles. Although each type of testing equipment usesthe same basic principles for light scattering as a function ofparticle size, different assumptions pertinent to application ofthe theory, and d
21、ifferent models for converting light measure-ments to particle size, may lead to different results for eachinstrument. Therefore, the use of this test method cannotguarantee directly comparable results from different types ofinstruments.5.3 Knowledge of the particle size distribution of metalpowders
22、 is useful in predicting the powder-processing behaviorand ultimate performance of powder metallurgy parts. Particlesize distribution is related closely to the flowability, moldabil-ity, compressibility, and die-filling characteristics of a powder,as well as to the final structure and properties of
23、finishedpowder metallurgy (P/M) parts.5.4 This test method is useful to both suppliers and users ofpowders in determining the particle size distributions forproduct specifications, manufacturing control, development,and research.5.5 This test method may be used to obtain data forcomparison between l
24、ots of the same material or for establish-ing conformance, as in acceptance testing.6. Interferences6.1 Air bubbles entrained in the circulating fluid will scatterlight and then be reported as particles. Circulating fluids maynot require degassing, but they should be bubble-free uponvisual inspectio
25、n.6.2 Contaminants, such as nonaqueous solvents, oil, orother organic coatings on the sample, may emulsify in anaqueous carrier, scatter light, and thus be reported as part of theparticle size distribution. Samples containing such contami-nants may be analyzed in a nonaqueous carrier solvent todisso
26、lve the contaminant, or they may be washed free of thecontaminant with a compatible aqueous solvent.6.3 The presence of oil, water, or foreign substances in agaseous dispersion will cause clogging or agglomeration orwill bias the particle size results. The gas supplied should befree of these substan
27、ces.6.4 Reagglomeration or settling of particulates duringanalysis will cause erroneous results. Dispersions shall beprepared in accordance with Guide B821, and a stable disper-sion shall be maintained throughout the analysis.6.5 Insufficient sample loading may cause electrical noiseinterference and
28、 poor data repeatability. Excessive sampleloading may cause excessive light attenuation and multiplescattering, resulting in erroneous particle size distributions.7. Apparatus7.1 Particle Size Analyzer, based on Fraunhofer Diffractionor Mie Scattering, or a combination of both light scatteringanalys
29、is techniques. Care must be taken to ensure that theanalyzer system or subsystem is optimum for the size range ofthe powder being tested.7.2 Liquid or Gaseous Sample Handling System.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise ind
30、icated, it is intended thatall reagents shall conform to the specifications of the Commit-tee onAnalytical Reagents of theAmerican Chemical Society.5Other grades may be used, provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accura
31、cy of the determination.8.2 Appropriate Application-Specific Carrier, as determinedby Guide B821. The carrier shall meet the following condi-tions:8.2.1 It shall be chemically compatible with the construc-tion material of the sample delivery system,8.2.2 It shall not cause dissolution of the particl
32、es, and8.2.3 It shall be sufficiently clean and non-absorbing toachieve acceptable background levels.8.3 Antifoaming Agent, or equivalent.8.4 Dry, Clean Gas, for gaseous dispersions.8.5 Appropriate Surfactant, as determined by Guide B821,subject to the conditions listed in 8.2.9. Sampling and Sample
33、 Size9.1 Obtain a test sample according to Practices B215. Thetest portion shall be extracted from the test sample using amicrosample splitter; quartering shall not be used.9.2 The maximum test sample for liquid dispersion will beno more than 25 g. No more than 500 g will be needed for agaseous disp
34、ersion.10. Calibration and Standardization10.1 Performance of the instrument is defined by the spac-ing and position of the optical components (refer to theinstruction manual provided by the manufacturer).10.2 No absolute standards are available for particle sizeanalysis. Diagnostic powders should b
35、e available from theequipment manufacturer to ensure consistent instrument func-tioning.5Reagent 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
36、 for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.B822 10211. Procedure11.1 Allow the instrument to warm up for a minimum of 20min.11.2 Install the desired sample delivery system
37、 and selectthe applicable instrument range, as indicated by the instruc-tions provided by the instrument manufacturer.11.3 Establish correct optical alignment, if necessary, ac-cording to the requirements of the manufacturer.NOTE 1Optical alignment should be checked upon startup, wheneverthe sample
38、delivery system is changed, or at least once a day.11.4 Measure the background in the mode in which theanalysis will be conducted. Be sure that the carrier is flowingthrough the light path while measuring background. Back-ground values shall not exceed the specifications of themanufacturer. If backg
39、round values exceed the recommenda-tions of the manufacturer, perform the necessary procedures asspecified by the manufacturer to bring the background valuesto within acceptable limits.11.5 Obtain a representative test sample according to Prac-tices B215. Extract a test portion from the test sample
40、using amicrosample splitter. Refer to the recommendations of theequipment manufacturer to ensure that the amount of the testportion is acceptable to achieve optimum light scatteringconditions. A wide range of sample sizes is acceptable,depending on median particle size (50 %), particle density(mass/
41、volume), and sample delivery system.11.6 Select the appropriate run time for the sample. Thisprocedure is very specific to the application and is generallygaged by the run-to-run repeatability.11.7 Select the desired data output parameters, according tothe requirements set forth by the instrument ma
42、nufacturer.11.8 For liquid dispersions, disperse the test portion accord-ing to the procedure outlined in Guide B821. Gaseous disper-sions require no additional sample preparation.11.9 Transfer the prepared sample directly to the sampledelivery system. In the liquid system, allow circulation for 20s
43、 before measuring. In the dry sampling system, engage thesample switch to allow the sample to begin to flow into thelight source before starting measurement.11.10 Perform the sample analysis according to the instruc-tions of the manufacturer.11.11 In the liquid system, drain and fill the sample disp
44、er-sion system in preparation for the next sample analysis. Drainand rinse as necessary, to achieve background values withinacceptable operating limits, as specified by the manufacturer.NOTE 2When changing from either polar to a nonpolar organic liquidor nonpolar to polar liquid, it will be necessar
45、y to rinse the sampledelivery system several times with a compatible solvent, such as alcohol,to eliminate the formation of an interference emulsion due to crosscontamination of the two carriers.11.12 In the dry gaseous system, brush or vacuum out allparticles throughout the sample system. Purge wit
46、h air toremove particles remaining in the sample delivery system.11.13 Repeat Steps 11.5 through 11.11 for additional testportion analyses.12. Report12.1 Practice E1617 specifies three detail levels for report-ing particle size characterization data. It is up to the supplierand the user of the data
47、to determine which level of reportingis needed. As a minimum, report the following information:12.1.1 The instrument name and model number used andthe range selected,12.1.2 The method of dispersing the test portion,12.1.3 The instrument analysis run time,12.1.4 Any curve fit models used (where appli
48、cable),12.1.5 The real and imaginary refractive index of the samplematerial (where applicable),12.1.6 The real refractive index of the dispersing liquid,12.1.7 The volume mean diameter,12.1.8 The differential volume percent versus diameter, and12.1.9 The cumulative volume percent versus diameter.13.
49、 Precision and Bias13.1 An interlaboratory study is being initiated to determinethe precision of this test method.13.2 PrecisionThe repeatability standard deviation of vol-ume mean diameter for one cobalt sample has been determinedto be 60.4 % relative standard deviation, based upon analysisin one laboratory. The reproducibility of this test method isbeing determined and will be available on or before June 30,2012.13.3 BiasNo information can be presented on the bias ofthe procedure in this test method for measuring particle sizedistribution because no metal powder h
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