1、Designation: B859 03 (Reapproved 2008)1B859 13Standard 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
2、adoption 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 NOTEEditorial changes were made in October 2008.1. Scope*1.1 This practice cov
3、ers the de-agglomeration of refractory metal powders and their compounds in preparation for particle sizeanalysis.1.2 Experience has shown that this practice is satisfactory for the de-agglomeration of elemental tungsten, molybdenum,rhenium, and tantalum metal powders, and tungsten carbide. Other me
4、tal powders (for example, elemental metals, carbides, andnitrides) may be prepared for particle size analysis using this practice with caution as to effectiveness until actual satisfactoryexperience is developed.1.3 With the exception of the values for mass, for which the use of the gram (g) unit is
5、 the long-standing industry practice, thevalues stated in SI are to be regarded as standard. No other units of measure are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this
6、standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific precautionary statements, see Note 2.2. Referenced Documents2.1 ASTM Standards:2B243 Terminology of Powder MetallurgyB330 Test Methods for Estimating Aver
7、age Particle Size of Metal Powders and Related Compounds Using Air PermeabilityB430 Test Method for Particle Size Distribution of Refractory Metal Powders and Related Compounds by TurbidimetryB761 Test Method for Particle Size Distribution of Metal Powders and Related Compounds by X-Ray Monitoring o
8、f GravitySedimentationB821 Guide for Liquid Dispersion of Metal Powders and Related Compounds for Particle Size AnalysisB822 Test Method for Particle Size Distribution of Metal Powders and Related Compounds by Light Scattering2.2 ASTM Adjunct:ADJB0859 Detailed Drawings of Alternative Steel Milling B
9、ottles33. Terminology3.1 DefinitionsDefinitions of powder metallurgy terms can be found in Terminology B243.4. Significance and Use4.1 Refractory metal powders, such as tungsten and molybdenum, are usually produced by hydrogen reduction at hightemperatures. Thus, they usually contain numerous large,
10、 strongly-sintered agglomerates. Many of the manufacturing processesusing these powders involve a milling step or some similar treatment or depend on the individual particulate size, not on the1 This practice is under the jurisdiction of ASTM Committee B09 on Metal Powders and Metal Powder Products
11、and is the direct responsibility of Subcommittee B09.03on Refractory Metal Powders.Current edition approved June 1, 2008Oct. 1, 2013. Published October 2008 October 2013. Originally approved in 1995. Last previous edition approved in 2003 as B859 03.03(2008)1. DOI: 10.1520/B0859-03R08E01.10.1520/B08
12、59-13.2 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 ASTM International Headquarters. Order
13、 Adjunct No. ADJB0859.This document is not an ASTM standard and is 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 u
14、sers consult prior editions as appropriate. In all cases only the 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 Cons
15、hohocken, PA 19428-2959. United States1agglomerate size.4 Thus, a knowledge of the individual particulate size distribution, not the agglomerate size distribution, is usuallydesired from a particle size analysis of these powders.This practice provides a procedure for breaking down agglomerates into
16、theirconstituent particles (de-agglomeration), without excessive fracture of the individual particles. The procedure is often referred toas laboratory milling or rod milling.4.2 The laboratory milling conditions specified in this guide have been in use since 1965 1965, initially as part of Test Meth
17、odaparticle B430. size analysis test method. This guide was first published as a separate, stand-alone standard in 1995 because of itsapplicability in preparing powder samples for analysis by other methods as well (for example, Test Methods B761 and B822), inaddition to Test Method ). B430. Informat
18、ion on the development and establishment of the milling conditions here specified canbe found in the footnoted reference.54.3 The milling procedure described in this practice does not necessarily break down only agglomerates without fracturingindividual particles; some particle fracture may occur in
19、 certain powders. However, use of this practice does provide consistentparticle size analysis results that have been found to relate well to powder behavior in numerous manufacturing processes.4.4 This practice shall be used for the de-agglomeration of the refractory metal powders and compounds list
20、ed in 1.11.2, whenan evaluation of the individual particulate size distribution is required from the subsequent particle size analysis. It shall not beused when the agglomerate (as-is or as-supplied) size distribution is desired.4.5 This practice may be used in preparing samples for Test Methods B33
21、0, B430, B761, B822, and other particle size analysismethods, prior to the dispersion procedure of Guide B821, if used.5. Apparatus5.1 Milling BottleThere are two alternative materials for the milling container:5.1.1 Glass BottleRound laboratory solution bottle, 250-mL capacity, or a 250-mL, 140-mm
22、high, 60-mm diameter,wide-mouth, flat-bottom centrifuge bottle, with cap or stopper, or5.1.2 Stainless Steel BottleFabricated according to the detailed drawings in Adjunct No. ADJB08593.5.2 Tungsten RodsFifty rods 7563 mm long by 4.060.3 mm in diameter (approximately 3 in. by 0.15 in.), diameter, gr
23、oundsurface.5.3 Laboratory Jar Roll Mill, capable of rotating the milling bottle 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 and usedon a faster rpm mill.5.4 Screen, No. 20 (850-m), and
24、Bottom Pan.6. Procedure6.1 Place 30 6 0.1 g of tungsten, molybdenum, rhenium, or tantalum 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 roll mill for 60 min6 15 s at a bottle speed of 145
25、 6 5 rpm. After the first 5min, check to be sure the rods are cascading inside the bottle by listening for the fast-paced, repeated “clinking” sound that thecascading rods make. If the rods are not cascading, stop the mill, set the bottle upright momentarily, then replace the bottle on themill and c
26、ontinue milling for the remaining 55 min (if the rods are now cascading; if not, repeat setting the bottle upright andrestarting until they are).6.3 After milling, immediately screen the powder through a No. 20 (850-m) screen to remove the milling rods. Dislodge anymilled powder that might remain in
27、 the bottle by placing a couple of screened rods in the bottle and “whipping” for a few turns.NOTE 2Warning: The fresh metal surfaces produced during milling may have a tendency to rapidly oxidize when the milling bottle is opened. Usecaution when opening the bottle to avoid fire or explosion.6.4 Re
28、move all the milled powder from the bottom pan and place in a sample container.7. Particle Size Analysis7.1 If necessary, disperse the milled powder according to Guide B821.7.2 Immediately perform the desired particle size analysis.NOTE 3Since milled powder has a greater tendency than as-supplied po
29、wder to pick up moisture and oxidize, the analysis procedure should beinitiated immediately after milling is completed. For all practical purposes, however, two runs can be made in succession on each milled powder. If more4 Michaels,A. I., “Turbidimetric Particle Size Distribution Theory:Application
30、 to Refractory Metal and Oxide Powders,” 1958 Symposium on Particle Size Measurement,ASTM STP 234, ASTM, 1959, pp. 207244.5 Buerkel, W. A., “Turbidimetric Particle Size Analysis as Applied to Tungsten Powder and the Carbide Industry,” Handbook of Metal Powders, A. Poster, ed., ReinholdPublishing Cor
31、p., New York, NY, 1966, pp. 2037.B859 132than two runs on the same milled powder are desired, provisions may be taken to lessen (elimination is not possible) the effect of humidity on the milledpowder, such as immediate splitting of the sample and storage under dry nitrogen or in a desiccator.8. Key
32、words8.1 de-agglomeration; laboratory-milled; laboratory milling; molybdenum; particle size analysis; powders; refractory metals;rhenium; rod-milled; rod milling; tantalum; tungsten; tungsten carbideSUMMARY OF CHANGESCommittee B09 has identified the location of selected changes made to this standard
33、 since the last issue,B85903, 03(2008)1, that may impact the use of this standard.(1) Footnotes 6 and 7 were editorially removed, as there is apparently more than one source for the apparatus.(1) A units statement was added, as Section 1.3.(2) References to now-obsolete Test Method B430 were deleted
34、.(3) Inch-pound units were removed.(2) Superscript 3 was added to Section 5.1.2, to refer to footnote 3.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
35、determination of the validity of any such 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 reapprove
36、d or withdrawn.Your comments are invited 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
37、that your comments have not received a 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 reprin
38、ts (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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).B859 133
