1、Designation: B 859 03 (Reapproved 2008)1Standard Practice forDe-Agglomeration of Refractory Metal Powders and TheirCompounds Prior to Particle Size Analysis1This standard is issued under the fixed designation B 859; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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.1NOTEEditorial changes were made in October 2008.1. Scope*1.1 This practice covers th
3、e de-agglomeration of refractorymetal powders and their 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 powde
4、rs (for example, elemental metals, carbides,and nitrides) may be prepared for particle size analysis usingthis practice with caution as to effectiveness until actualsatisfactory experience is developed.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with i
5、ts 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. For specificprecautionary statements, see Note 2.2. Referenced Documents2.1 ASTM Standards:2B 243 Terminology of
6、 Powder MetallurgyB 330 Test Method for Fisher Number of Metal Powdersand Related CompoundsB 430 Test Method for Particle Size Distribution of Refrac-tory Metal Powders and Related Compounds by Turbidim-etryB 761 Test Method for Particle Size Distribution of MetalPowders and Related Compounds by X-R
7、ay Monitoring ofGravity SedimentationB 821 Guide for Liquid Dispersion of Metal Powders andRelated Compounds for Particle Size AnalysisB 822 Test Method for Particle Size Distribution of MetalPowders and Related Compounds by Light Scattering2.2 ASTM Adjunct:ADJB0859 Detailed Drawings of Alternative
8、Steel MillingBottles33. Terminology3.1 DefinitionsDefinitions of powder metallurgy termscan be found in Terminology B 243.4. Significance and Use4.1 Refractory metal powders, such as tungsten and molyb-denum, are usually produced by hydrogen reduction at hightemperatures. Thus, they usually contain
9、numerous large,strongly-sintered agglomerates. Many of the manufacturingprocesses using these powders involve a milling step or somesimilar treatment or depend on the individual particulate size,not on the agglomerate size.4Thus, a knowledge of theindividual particulate size distribution, not the ag
10、glomeratesize distribution, is usually desired from a particle size analysisof these powders. This practice provides a procedure forbreaking down agglomerates into their constituent particles(de-agglomeration), without excessive fracture of the indi-vidual particles. The procedure is often referred
11、to as labora-tory milling or rod milling.4.2 The laboratory milling conditions specified in this guidehave been in use since 1965 as part of Test Method B 430. Thisguide was first published as a separate, stand-alone standard in1995 because of its applicability in preparing powder samplesfor analysi
12、s by other methods (for example, Test MethodsB 761 and B 822), in addition to Test Method B 430. Informa-tion on the development and establishment of the millingconditions here specified can be found in the footnotedreference.51This practice is under the jurisdiction of ASTM Committee B09 on MetalPo
13、wders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.03 on Refractory Metal Powders.Current edition approved June 1, 2008. Published October 2008. Originallyapproved in 1995. Last previous edition approved in 2003 as B 859 03.2For referenced ASTM standards, visit the
14、 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.3Available from ASTM International Headquarters. Order Adjunct No.ADJB0859.4Michaels, A. I., “Turbidim
15、etric Particle Size Distribution Theory: Applicationto Refractory Metal and Oxide Powders,” 1958 Symposium on Particle SizeMeasurement, ASTM STP 234, ASTM, 1959, pp. 207244.5Buerkel, W. A., “Turbidimetric Particle Size Analysis as Applied to TungstenPowder and the Carbide Industry,” Handbook of Meta
16、l Powders, A. Poster, ed.,Reinhold Publishing Corp., New York, NY, 1966, pp. 2037.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.3 The milling procedure described i
17、n this practice doesnot necessarily 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
18、numerous manufacturingprocesses.4.4 This practice shall be used for the de-agglomeration ofthe refractory metal powders and compounds listed in 1.1,when an evaluation of the individual particulate size distribu-tion is required from the subsequent particle size analysis. Itshall not be used when the
19、 agglomerate (as-is or as-supplied)size distribution is desired.4.5 This practice may be used in preparing samples for TestMethods B 330, B 430, B 761, B 822, and other particle sizeanalysis methods, prior to the dispersion procedure of GuideB 821, if used.5. Apparatus5.1 Milling BottleThere are two
20、 alternative materials forthe milling container:5.1.1 Glass BottleRound laboratory solution bottle,250-mL capacity, or a 250-mL, 140-mm high, 60-mm diam-eter, wide-mouth, flat-bottom centrifuge bottle, with cap orstopper, or5.1.2 Stainless Steel BottleFabricated according to thedetailed drawings in
21、Adjunct No. ADJB08593.5.2 Tungsten RodsFifty rods 75 6 3 mm long by 4.0 60.3 mm in diameter (approximately 3 in. by 0.15 in.), groundsurface.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
22、 can be either (1) set up on a lathe, or (2) built up in diameter andused on 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
23、50 tungsten milling rods.6.2 Seal the milling bottle and rotate on the jar roll 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
24、. If the rods are not cascading, stop themill, set the bottle upright momentarily, 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 sc
25、reen the powder through aNo. 20 (850-m) screen to remove the milling rods. Dislodgeany 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 r
26、apidly oxidize when the milling bottle is opened.Use caution when opening the 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 B 821.7.2 Immedi
27、ately perform the desired particle size analysis.NOTE 3Since milled powder has a greater tendency than as-suppliedpowder to pick up moisture and oxidize, the analysis procedure should beinitiated immediately after milling is completed. For all practical pur-poses, however, two runs can be made in su
28、ccession on each milledpowder. If more than two runs on the same milled powder 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. Keyword
29、s8.1 de-agglomeration; laboratory-milled; laboratory mill-ing; molybdenum; particle size analysis; powders; refractorymetals; rhenium; rod-milled; rod milling; tantalum; tungsten;tungsten carbideSUMMARY OF CHANGESCommittee B09 has identified the location of selected changes made to this standard sin
30、ce the last issue,B 85903, that may impact the use of this standard.(1) Footnotes 6 and 7 were editorially removed, as there isapparently more than one source for the apparatus.(2) Superscript 3 was added to Section 5.1.2, to refer tofootnote 3.B 859 03 (2008)12ASTM International takes no position r
31、especting 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 rights, and the riskof infringement of such rights, are entirely their own responsibility.Thi
32、s 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 revision of this standard or for additional standardsand should be addressed to ASTM Inte
33、rnational 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 you shouldmake your views known to the ASTM Committee on Standards, at the address shown
34、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 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).B 859 03 (2008)13
