1、Designation: B761 17Standard Test Method forParticle Size Distribution of Metal Powders and RelatedCompounds by X-Ray Monitoring of Gravity Sedimentation1This standard is issued under the fixed designation B761; 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. Scope*1.1 This test method covers the determination of particlesize distributions of m
3、etal powders. Experience has shown thatthis test method is satisfactory for the analysis of elementaltungsten, tungsten carbide, molybdenum, and tantalumpowders, all with an as-supplied estimated average particle sizeof 6 m or less, as determined by Test Method B330. Othermetal powders (for example,
4、 elemental metals, carbides, andnitrides) may be analyzed using this test method with cautionas to significance until actual satisfactory experience is devel-oped (see 7.2). The procedure covers the determination ofparticle size distribution of the powder in the following twoconditions:1.1.1 As the
5、powder is supplied (as-supplied), and1.1.2 After the powder has been deagglomerated by rodmilling as described in Practice B859.1.2 This test method is applicable to particles of uniformdensity and composition having a particle size distributionrange of 0.1 up to 100 m.1.2.1 However, the relationshi
6、p between size and sedimen-tation velocity used in this test method assumes that particlessediment within the laminar flow regime. This requires that theparticles sediment with a Reynolds number of 0.3 or less.Particle size distribution analysis for particles settling with alarger Reynolds number ma
7、y be incorrect due to turbulent flow.Some materials covered by this test method may settle withReynolds number greater than 0.3 if particles greater than 25m are present. The user of this test method should calculatethe Reynolds number of the largest particle expected to bepresent in order to judge
8、the quality of obtained results.Reynolds number (Re) can be calculated using the flowingequationRe 5D3 2 0!0g182(1)whereD = the diameter of the largest particle expected to bepresent, = the particle density,0= the suspending liquid density,g = the acceleration due to gravity, and = is the suspending
9、 liquid viscosity.A table of the largest particles that can be analyzed withReynolds number of 0.3 or less in water at 35C is given for anumber of metals in Table 1.Acolumn of the Reynolds numbercalculated for a 30m particle sedimenting in the same liquidsystem is given for each material also.1.3 Un
10、itsWith the exception of the values for density andthe mass used to determine density, for which the use of thegram per cubic centimetre (g/cm3) and gram (g) units is thelongstanding industry practice, the values in SI units are to beregarded as standard.1.4 This standard does not purport to address
11、 all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.Specific hazard information is given in Sect
12、ion 7.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarri
13、ers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2B330 Test Methods for Estimating Average Particle Size ofMetal Powders and Related Compounds Using Air Per-meabilityB821 Guide for Liquid Dispersion of Metal Powders andRelated Compounds for Particle Size Analysis1This test meth
14、od is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.03 on Refractory Metal Powders.Current edition approved Oct. 15, 2017. Published December 2017. Originallyapproved in 1986. Last previous edition approve
15、d in 2011 as B761 06(2011). DOI:10.1520/B0761-17.2For 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 Summary page onthe ASTM website.*A Summary o
16、f Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in t
17、he Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1B859 Practice for De-Agglomeration of Refractory MetalPowders and Their Compounds Prior to Particle SizeAnalysisE456
18、 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Method3.1 A carefully dispersed homogeneous suspension of thepowder is permitted to settle in a cell scanned by a collimatedX-ray beam of
19、constant intensity. The net X-ray signal isinversely proportional to the sample concentration in thedispersing medium, and the particle diameter is related to theposition of the X-ray beam relative to the top of the cell.Cumulative mass percent versus equivalent spherical diameterare recorded to yie
20、ld a particle size distribution curve.4. Significance and Use4.1 This test method is useful to both producers andpurchasers of powders, as outlined in 1.1 and 1.2, in determin-ing particle size distribution for product specifications, manu-facturing control, development, and research.4.2 Users shoul
21、d be aware that sample concentrations usedin this test method may not be what is considered ideal by someauthorities, and that the range of this test method extends intothe region where Brownian movement could be a factor inconventional sedimentation. Within the range of this testmethod, neither the
22、 sample concentration nor Brownian move-ment are believed to be significant.4.3 Reported particle size measurement is a function of boththe actual particle dimension and shape factor as well as theparticular physical or chemical properties being measured.Caution is required when comparing data from
23、instrumentsoperating on different physical or chemical parameters or withdifferent particle size measurement ranges. Sample acquisition,handling, and preparation can also affect reported particle sizeresults.5. Apparatus5.1 Gravitational sedimentation particle size analyzer utiliz-ing X-ray extincti
24、on to determine particle concentration.36. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society
25、wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Dispersing MediumDissolve 0.10 g of sodium hexam-etaphosphate (NaPO3)6 in 1000 mL
26、of distilled or deionizedwater.6.3 Cleaning SolutionDissolve 0.5 g of laboratory deter-gent in 1000 mL of distilled or deionized water, or prepare a0.1 % solution by volume of Triton X-100 using distilled ordeionized water.57. Hazards7.1 Precautions applying to the use of low intensity X-rayunits sh
27、ould be observed.3The sole instrument of this type known to the committee as this time is theSediGraph X-ray gravity sedimentation particle size analyzer, available fromMicromeritics Instrument Corporation, 4356 Communications Drive, Norcross, GA30093. If you are aware of alternative suppliers, plea
28、se provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For sugge
29、stions 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. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5Triton X-100 is a trademarked
30、 product of Rohm six or more recommended), the user of this testmethod may infer its precision from this interlaboratory study.The pertinent conclusions are presented below:11.1.1 The within-laboratory repeatability limit, r, for themedian particle size (r as defined by Terminology E456), wasfound t
31、o be estimated by the following equation:r 5 0.133M 2 0.009 (2)whereM = the measured median particle size (m), in the range of1.4 to 4.2 m (r = 0.15 to 0.55 m in this range).Duplicate median particle size results from the same laboratoryshould not be considered suspect unless they differ by morethan
32、 r.11.1.2 The between-laboratory reproducibility limit, R, forthe median particle size (R as defined by Terminology E456)was found to be estimated by the following equation:R 5 0.482M 2 0.489 (3)whereM = the measured median particle size (m) in the range of1.4 to 4.2 m (R = 0.19 to 1.54 m in this ra
33、nge).Median particle size results from two different laboratoriesshould not be considered suspect unless they differ by morethan R.6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:B09-1011.TABLE 2 Suggested Approximate Starting M
34、asses for Tungstenor Tungsten CarbideNominal Average Particle SizeEstimated According to Test MethodB330 of As-Supplied Powder, mMassA, g per 60 mL of Dispersing Me-dium1 0.502 0.553 0.624 0.675 0.726 0.79AThe amount of sample required will vary. Increase or decrease the sample massas needed to prov
35、ide the level of X-ray attenuation recommended in analyzerinstruction manual.B761 17311.2 BiasNo absolute method of determining powderparticle size exists, nor are there any universally recognizedstandard or reference powders for this measurement.Therefore, it is not possible to discuss the bias res
36、ults by thistest method.12. Keywords12.1 metal powders; particle size; particle size distribution;powdered metals; refractory metal powders; sedimentationparticle size distributionSUMMARY OF CHANGESCommittee B09 has identified the location of selected changes to this standard since the last issue,B7
37、61 06(2011), that may impact the use of this standard. (Approved October 15, 2017.)(1) References to Fisher number have been changed to particlesize estimated using Test Method B330 in two places, para-graph 1.1 and Table 2.(2) A statement on Units usage, taken from the B09 PolicyGuide, was added as
38、 paragraph 1.3. This resulted in renumber-ing the paragraph that follows it to 1.4.(3) The terms “suppliers and users” was changed to “producersand purchasers” in paragraph 4.1.(4) The terms “weight” and “weights” were replaced with“mass” and “masses, respectively, in five places, once inparagraph 9
39、.3, once in Note 1, and three times in Table 2.(5) The address for the sole known producer of this type ofinstrumentation was corrected in Footnote 3.(6) Note 4 was removed.(7) The volume of dispersing medium listed Table 2, alongwith the corresponding masses of sample to use, was updatedto match wh
40、at is typically used with current instrumentation.ASTM International takes no position 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 right
41、s, 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 must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for r
42、evision of this standard or for additional standardsand should be addressed to ASTM International 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 y
43、ou 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 C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may b
44、e 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 174
