1、Designation: B859 13 (Reapproved 2018)Standard Practice forDe-Agglomeration of Refractory Metal Powders and TheirCompounds Prior to Particle Size Analysis1This standard is issued under the fixed designation B859; 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 practice covers the de-agglomeration of refractorymetal powders and th
3、eir compounds in preparation for particlesize analysis.1.2 Experience has shown that this practice is satisfactoryfor the de-agglomeration of elemental tungsten, molybdenum,rhenium, and tantalum metal powders, and tungsten carbide.Other metal powders (for example, elemental metals, carbides,and nitr
4、ides) may be prepared for particle size analysis usingthis practice with caution as to effectiveness until actualsatisfactory experience is developed.1.3 With the exception of the values for mass, for which theuse of the gram (g) unit is the long-standing industry practice,the values stated in SI ar
5、e to be regarded as standard. No otherunits of measure are included in this standard.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 to establish appro-priate safety, health, and environmen
6、tal practices and deter-mine the applicability of regulatory limitations prior to use.For specific precautionary statements, see Note 2.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principle
7、s for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2B243 Terminology of Powder MetallurgyB330 Test Methods for Estimating Average Particle Size ofMeta
8、l Powders and Related Compounds Using Air Per-meabilityB761 Test Method for Particle Size Distribution of MetalPowders and Related Compounds by X-Ray Monitoringof Gravity SedimentationB821 Guide for Liquid Dispersion of Metal Powders andRelated Compounds for Particle Size AnalysisB822 Test Method fo
9、r Particle Size Distribution of MetalPowders and Related Compounds by Light Scattering2.2 ASTM Adjunct:ADJB0859 Detailed Drawings of Alternative Steel MillingBottles33. Terminology3.1 DefinitionsDefinitions of powder metallurgy termscan be found in Terminology B243.4. Significance and Use4.1 Refract
10、ory metal powders, such as tungsten andmolybdenum, are usually produced by hydrogen reduction athigh temperatures. Thus, they usually contain numerous large,strongly-sintered agglomerates. Many of the manufacturingprocesses using these powders involve a milling step or somesimilar treatment or depen
11、d on the individual particulate size,not on the agglomerate size.4Thus, a knowledge of theindividual particulate size distribution, not the agglomeratesize distribution, is usually desired from a particle size analysisof these powders. This practice provides a procedure forbreaking down agglomerates
12、 into their constituent particles(de-agglomeration), without excessive fracture of the indi-vidual particles. The procedure is often referred to as labora-tory milling or rod milling.4.2 The laboratory milling conditions specified in this guidehave been in use since 1965, initially as part of a part
13、icle sizeanalysis test method. This guide was first published as a1This practice 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 April 1, 2018. Publ
14、ished May 2018. Originallyapproved in 1995. Last previous edition approved in 2003 as B859 13. DOI:10.1520/B0859-13R18.2For 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
15、to the standards Document Summary page onthe ASTM website.3Available from ASTM International Headquarters. Order Adjunct No.ADJB0859.4Michaels, A. I., “Turbidimetric Particle Size Distribution Theory: Applicationto Refractory Metal and Oxide Powders,” 1958 Symposium on Particle SizeMeasurement, ASTM
16、 STP 234, ASTM, 1959, pp. 207244.*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 StatesThis international standard was developed in accordance with internationally recognized p
17、rinciples on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1separate, stand-alone standard in 1995 because of its applica-bility in
18、 preparing powder samples for analysis by othermethods as well (for example, Test Methods B761 and B822).Information on the development and establishment of themilling conditions here specified can be found in the footnotedreference.54.3 The milling procedure described in this practice doesnot neces
19、sarily break down only agglomerates without fractur-ing individual particles; some particle fracture may occur incertain powders. However, use of this practice does provideconsistent particle size analysis results that have been found torelate well to powder behavior in numerous manufacturingprocess
20、es.4.4 This practice shall be used for the de-agglomeration ofthe refractory metal powders and compounds listed in 1.2,when an evaluation of the individual particulate size distribu-tion is required from the subsequent particle size analysis. Itshall not be used when the agglomerate (as-is or as-sup
21、plied)size distribution is desired.4.5 This practice may be used in preparing samples for TestMethods B330, B761, B822, and other particle size analysismethods, prior to the dispersion procedure of Guide B821,ifused.5. Apparatus5.1 Milling BottleThere are two alternative materials forthe milling con
22、tainer:5.1.1 Glass BottleRound laboratory solution bottle,250-mL capacity, or a 250-mL, 140-mm high, 60-mmdiameter, wide-mouth, flat-bottom centrifuge bottle, with capor stopper, or5.1.2 Stainless Steel BottleFabricated according to thedetailed drawings in Adjunct No. ADJB08593.5.2 Tungsten RodsFift
23、y rods 75 6 3 mm long by 4.0 60.3 mm in diameter, ground surface.5.3 Laboratory Jar Roll Mill, capable of rotating the millingbottle at 145 rpm.NOTE 1If a jar roll mill is not available to give a bottle rpm of 145,the bottle can be either (1) set up on a lathe, or (2) built up in diameter andused on
24、 a faster rpm mill.5.4 Screen, No. 20 (850-m), and Bottom Pan.6. Procedure6.1 Place 30 6 0.1 g of tungsten, molybdenum, rhenium, ortantalum metal, or 50 6 0.1 g of tungsten carbide powder in themilling bottle containing the 50 tungsten milling rods.6.2 Seal the milling bottle and rotate on the jar r
25、oll mill for60 min6 15 s at a bottle speed of 145 6 5 rpm. After the first5 min, check to be sure the rods are cascading inside the bottleby listening for the fast-paced, repeated “clinking” sound thatthe cascading rods make. If the rods are not cascading, stop themill, set the bottle upright moment
26、arily, then replace the bottleon the mill and continue milling for the remaining 55 min (ifthe rods are now cascading; if not, repeat setting the bottleupright and restarting until they are).6.3 After milling, immediately screen the powder through aNo. 20 (850-m) screen to remove the milling rods. D
27、islodgeany milled powder that might remain in the bottle by placing acouple of screened rods in the bottle and “whipping” for a fewturns.NOTE 2Warning: The fresh metal surfaces produced during millingmay have a tendency to rapidly oxidize when the milling bottle is opened.Use caution when opening th
28、e bottle to avoid fire or explosion.6.4 Remove all the milled powder from the bottom pan andplace in a sample container.7. Particle Size Analysis7.1 If necessary, disperse the milled powder according toGuide B821.7.2 Immediately perform the desired particle size analysis.NOTE 3Since milled powder ha
29、s a greater tendency than as-suppliedpowder to pick up moisture and oxidize, the analysis procedure should beinitiated immediately after milling is completed. For all practicalpurposes, however, two runs can be made in succession on each milledpowder. If more than two runs on the same milled powder
30、are desired,provisions may be taken to lessen (elimination is not possible) the effectof humidity on the milled powder, such as immediate splitting of thesample and storage under dry nitrogen or in a desiccator.8. Keywords8.1 de-agglomeration; laboratory-milled; laboratory mill-ing; molybdenum; part
31、icle size analysis; powders; refractorymetals; rhenium; rod-milled; rod milling; tantalum; tungsten;tungsten carbide5Buerkel, W. A., “Turbidimetric Particle Size Analysis as Applied to TungstenPowder and the Carbide Industry,” Handbook of Metal Powders, A. Poster, ed.,Reinhold Publishing Corp., New
32、York, NY, 1966, pp. 2037.B859 13 (2018)2SUMMARY OF CHANGESCommittee B09 has identified the location of selected changes made to this standard since the last issue, B85903(2008)1, that may impact the use of this standard.(1) A units statement was added, as Section 1.3.(2) References to now-obsolete T
33、est Method B430 were de-leted.(3) Inch-pound units were removed.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 suc
34、h 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 must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invite
35、d 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 theresponsible technical committee, which you may attend. If you feel that your comments have not received a
36、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 C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this
37、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). 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:/ 13 (2018)3
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