1、Designation: B822 10B822 17Standard 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
2、 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 particle size distribution by light scatterin
3、g, reported as volume percent,of particulate materials including metals and compounds.1.2 This test method applies to analyses with both aqueous and nonaqueous dispersions. In addition, analysis can be performedwith a gaseous dispersion for materials that are hygroscopic or react with a liquid carri
4、er.1.3 This test method is applicable to the measurement of particulate materials in the range of 0.4 to 2000 m, or a subset ofthat range, as applicable to the particle size distribution being measured.1.4 The values stated in SI units are to be regarded as the standard.1.5 This standard does not pu
5、rport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.6 This international standard was developed
6、in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1
7、 ASTM Standards:2B215 Practices for Sampling Metal PowdersB243 Terminology of Powder MetallurgyB821 Guide for Liquid Dispersion of Metal Powders and Related Compounds for Particle Size AnalysisE1617 Practice for Reporting Particle Size Characterization Data2.2 ISO Standard:3ISO13320-1 Particle Size
8、AnalysisLaser Diffraction MethodsPart 1: General Principles3. Terminology3.1 DefinitionsDefinitions of powder metallurgy terms can be found in Terminology B243.3.2 Definitions of Terms Specific to This Standard:3.2.1 backgroundextraneous scattering of light by elements other than the particles to be
9、 measured; includes scattering bycontamination in the measurement path.3.2.2 Fraunhofer Diffractionthe optical theory that describes the low-angle scattering of light by particles that are largecompared to the wavelength of the incident light.43.2.3 Mie Scatteringthe complex electromagnetic theory t
10、hat describes the scattering of light by spherical particles. It isusually applied to particles with diameters that are close to the wavelength of the incident light. The real and imaginary indicesof light refraction of the particles are needed.41 This test method is under the jurisdiction ofASTM Co
11、mmittee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.02on Base Metal Powders.Current edition approved May 1, 2010April 1, 2017. Published June 2010April 2017. Originally published as B822 92. Last previous edition approved in 2010 asB822 02.B822
12、 10. DOI: 10.1520/B0822-10.10.1520/B0822-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from
13、American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.4 Muly, E. C., Frock, H. N., “Industrial Particle Size Measurement Using Light Scattering,” Optical Engineering, Vol 19, No 6, 1980, pp. 861869.This document is not an ASTM standard and is
14、 intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the
15、current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.4 multiple scatteringth
16、e rescattering of light by a particle in the path of light scattered by another particle. This usuallyoccurs in heavy concentrations of a particle dispersion.4. Summary of Test Method4.1 A prepared sample of particulate material is dispersed in water, or a compatible organic liquid, and circulated t
17、hrough thepath of a light beam or some other suitable light source. A dry sample may be aspirated through the light in a carrier gas. Theparticles pass through the light beam and scatter it. Photodetector arrays collect the scattered light that is converted to electricalsignals, which are then analy
18、zed in a microprocessor. The signal is converted to a size distribution using Fraunhofer Diffractionor Mie Scattering, or a combination of both. Scattering information is analyzed assuming a spherical model. Calculated particlesizes are therefore presented as equivalent spherical diameters. Addition
19、al information pertaining to the general principles ofparticle size distribution analysis by light scattering can be found in ISO Standard 13320-1.5. Significance and Use5.1 Reported particle size measurement is a function of both the actual particle dimension and shape factor as well as theparticul
20、ar physical or chemical properties being measured. Caution is required when comparing data from instruments operatingon different physical or chemical parameters or with different particle size measurement ranges. Sample acquisition, handling, andpreparation can also affect reported particle size re
21、sults.5.1.1 It is important to recognize that the results obtained by this test method, or any other method for particle size determinationusing different physical principles, may disagree. The results are strongly influenced by the physical principles employed by eachmethod of particle size analysi
22、s. The results of any particle sizing method should be used only in a relative sense; they should notbe regarded as absolute when comparing results obtained by other methods.5.2 Light scattering theory has been available for many years for use in the determination of particle size. Several manufactu
23、rersof testing equipment now have units based on these principles. Although each type of testing equipment uses the same basicprinciples for light scattering as a function of particle size, different assumptions pertinent to application of the theory, and differentmodels for converting light measure
24、ments to particle size, may lead to different results for each instrument. Therefore, the use ofthis test method cannot guarantee directly comparable results from different types of instruments.5.3 Knowledge of the particle size distribution of metal powders is useful in predicting the powder-proces
25、sing behavior andultimate performance of powder metallurgy parts. Particle size distribution is related closely to the flowability, moldability,compressibility, and die-filling characteristics of a powder, as well as to the final structure and properties of finished powdermetallurgy (P/M) parts.5.4
26、This test method is useful to both suppliers and users of powders in determining the particle size distributions for productspecifications, manufacturing control, development, and research.5.5 This test method may be used to obtain data for comparison between lots of the same material or for establi
27、shingconformance, as in acceptance testing.6. Interferences6.1 Air bubbles entrained in the circulating fluid will scatter light and then be reported as particles. Circulating fluids may notrequire degassing, but they should be bubble-free upon visual inspection.6.2 Contaminants, such as nonaqueous
28、solvents, oil, or other organic coatings on the sample, may emulsify in an aqueouscarrier, scatter light, and thus be reported as part of the particle size distribution. Samples containing such contaminants may beanalyzed in a nonaqueous carrier solvent to dissolve the contaminant, or they may be wa
29、shed free of the contaminant with acompatible aqueous solvent.6.3 The presence of oil, water, or foreign substances in a gaseous dispersion will cause clogging or agglomeration or will biasthe particle size results. The gas supplied should be free of these substances.6.4 Reagglomeration or settling
30、of particulates during analysis will cause erroneous results. Dispersions shall be prepared inaccordance with Guide B821, and a stable dispersion shall be maintained throughout the analysis.6.5 Insufficient sample loading may cause electrical noise interference and poor data repeatability. Excessive
31、 sample loadingmay cause excessive light attenuation and multiple scattering, resulting in erroneous particle size distributions.7. Apparatus7.1 Particle Size Analyzer, based on Fraunhofer Diffraction or Mie Scattering, or a combination of both light scattering analysistechniques. Care must be taken
32、 to ensure that the analyzer system or subsystem is optimum for the size range of the powder beingtested.7.2 Liquid or Gaseous Sample Handling System.B822 1728. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended
33、that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society.5 Othergrades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lesseningthe accuracy of the determinati
34、on.8.2 Appropriate Application-Specific Carrier, as determined by Guide B821. The carrier shall meet the following conditions:8.2.1 It shall be chemically compatible with the construction material of the sample delivery system,8.2.2 It shall not cause dissolution of the particles, and8.2.3 It shall
35、be sufficiently clean and non-absorbing to achieve 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 Size9.1 Obtain a te
36、st sample according to Practices B215. The test 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 be no more than 25 g. No more than 500 g will be needed for a gaseousdispersion.10. Calibra
37、tion and Standardization10.1 Performance of the instrument is defined by the spacing and position of the optical components (refer to the instructionmanual provided by the manufacturer).10.2 No absolute standards are available for particle size analysis. Diagnostic powders should be available from t
38、he equipmentmanufacturer to ensure consistent instrument functioning.11. Procedure11.1 Allow the instrument to warm up for a minimum of 20 min.11.2 Install the desired sample delivery system and select the applicable instrument range, as indicated by the instructionsprovided by the instrument manufa
39、cturer.11.3 Establish correct optical alignment, if necessary, according to the requirements of the manufacturer.NOTE 1Optical alignment should be checked upon startup, whenever the sample delivery system is changed, or at least once a day.11.4 Measure the background in the mode in which the analysi
40、s will be conducted. Be sure that the carrier is flowing throughthe light path while measuring background. Background values shall not exceed the specifications of the manufacturer. Ifbackground values exceed the recommendations of the manufacturer, perform the necessary procedures as specified by t
41、hemanufacturer to bring the background values to within acceptable limits.11.5 Obtain a representative test sample according to Practices B215. Extract a test portion from the test sample using amicrosample splitter. Refer to the recommendations of the equipment manufacturer to ensure that the amoun
42、t of the test portionis acceptable to achieve optimum light scattering conditions. A wide range of sample sizes is acceptable, depending on medianparticle size (50 %), particle density (mass/volume), and sample delivery system.11.6 Select the appropriate run time for the sample. This procedure is ve
43、ry specific to the application and is generally gagedby the run-to-run repeatability.11.7 Select the desired data output parameters, according to the requirements set forth by the instrument manufacturer.11.8 For liquid dispersions, disperse the test portion according to the procedure outlined in Gu
44、ide B821. Gaseous dispersionsrequire no additional sample preparation.11.9 Transfer the prepared sample directly to the sample delivery system. In the liquid system, allow circulation for 20 s beforemeasuring. In the dry sampling system, engage the sample switch to allow the sample to begin to flow
45、into the light source beforestarting measurement.11.10 Perform the sample analysis according to the instructions of the manufacturer.5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe A
46、merican Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.B822 17311.11 In the liquid system, drain and fill the sample dispersion system
47、in preparation for the next sample analysis. Drain andrinse as necessary, to achieve background values within acceptable operating limits, as specified by the manufacturer.NOTE 2When changing from either polar to a nonpolar organic liquid or nonpolar to polar liquid, it will be necessary to rinse th
48、e sample deliverysystem several times with a compatible solvent, such as alcohol, to eliminate the formation of an interference emulsion due to cross contamination ofthe two carriers.11.12 In the dry gaseous system, brush or vacuum out all particles throughout the sample system. Purge with air to re
49、moveparticles remaining in the sample delivery system.11.13 Repeat Steps 11.5 through 11.11 for additional test portion analyses.12. Report12.1 Practice E1617 specifies three detail levels for reporting particle size characterization data. It is up to the supplier and theuser of the data to determine which level of reporting is needed. As a minimum, report the following information:12.1.1 The instrument name and model number used and the 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 mo
