Standard Practice for De-Agglomeration of Refractory Metal Powders and Their Compounds Prior to Particle Size Analysis

SIGNIFICANCE AND USE
Refractory metal powders, such as tungsten and molybdenum, are usually produced by hydrogen reduction at high temperatures. Thus, they usually contain numerous large, strongly-sintered agglomerates. Many of the manufacturing processes using these powders involve a milling step or some similar treatment or depend on the individual particulate size, not on the agglomerate size. Thus, a knowledge of the individual particulate size distribution, not the agglomerate size distribution, is usually desired from a particle size analysis of these powders. This practice provides a procedure for breaking down agglomerates into their constituent particles (de-agglomeration), without excessive fracture of the individual particles. The procedure is often referred to as laboratory milling or rod milling.
The laboratory milling conditions specified in this guide have been in use since 1965 as part of Test Method B 430. This guide was first published as a separate, stand-alone standard in 1995 because of its applicability in preparing powder samples for analysis by other methods (for example, Test Methods B 761 and B 822), in addition to Test Method B 430. Information on the development and establishment of the milling conditions here specified can be found in the footnoted reference.  
The milling procedure described in this practice does not necessarily break down only agglomerates without fracturing individual particles; some particle fracture may occur in certain powders. However, use of this practice does  provide consistent particle size analysis results that have been found to relate well to powder behavior in numerous manufacturing processes.
This practice shall be used for the de-agglomeration of the refractory metal powders and compounds listed in 1.1, when an evaluation of the individual particulate size distribution is required from the subsequent particle size analysis. It shall not be used when the agglomerate (as-is or as-supplied) size distribution is desired.
...
SCOPE
1.1 This practice covers the de-agglomeration of refractory metal powders and their compounds in preparation for particle size analysis.  
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 metal powders (for example, elemental metals, carbides, and nitrides) may be prepared for particle size analysis using this practice with caution as to effectiveness until actual satisfactory experience is developed.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Note 2.

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: B859 − 03(Reapproved 2008)
Standard Practice for
De-Agglomeration of Refractory Metal Powders and Their
Compounds Prior to Particle Size Analysis
This standard is issued under the fixed designation B859; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
´ NOTE—Editorial changes were made in October 2008.
1. Scope* Related Compounds for Particle Size Analysis
B822 Test Method for Particle Size Distribution of Metal
1.1 This practice covers the de-agglomeration of refractory
Powders and Related Compounds by Light Scattering
metal powders and their compounds in preparation for particle
size analysis.
2.2 ASTM Adjunct:
ADJB0859 Detailed Drawings of Alternative Steel Milling
1.2 Experience has shown that this practice is satisfactory
Bottles
for the de-agglomeration of elemental tungsten, molybdenum,
rhenium, and tantalum metal powders, and tungsten carbide.
3. Terminology
Other metal powders (for example, elemental metals, carbides,
and nitrides) may be prepared for particle size analysis using
3.1 Definitions—Definitions of powder metallurgy terms
this practice with caution as to effectiveness until actual
can be found in Terminology B243.
satisfactory experience is developed.
1.3 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
4.1 Refractory metal powders, such as tungsten and
responsibility of the user of this standard to establish appro-
molybdenum, are usually produced by hydrogen reduction at
priate safety and health practices and determine the applica-
high temperatures. Thus, they usually contain numerous large,
bility of regulatory limitations prior to use. For specific
strongly-sintered agglomerates. Many of the manufacturing
precautionary statements, see Note 2.
processes using these powders involve a milling step or some
2. Referenced Documents similar treatment or depend on the individual particulate size,
not on the agglomerate size. Thus, a knowledge of the
2.1 ASTM Standards:
individual particulate size distribution, not the agglomerate
B243 Terminology of Powder Metallurgy
size distribution, is usually desired from a particle size analysis
B330 Test Method for Fisher Number of Metal Powders and
of these powders. This practice provides a procedure for
Related Compounds
breaking down agglomerates into their constituent particles
B430 Test Method for Particle Size Distribution of Refrac-
(de-agglomeration), without excessive fracture of the indi-
tory Metal Powders and Related Compounds by Turbidi-
vidual particles. The procedure is often referred to as labora-
metry
tory milling or rod milling.
B761 Test Method for Particle Size Distribution of Metal
Powders and Related Compounds by X-Ray Monitoring
4.2 The laboratory milling conditions specified in this guide
of Gravity Sedimentation
have been in use since 1965 as part of Test Method B430. This
B821 Guide for Liquid Dispersion of Metal Powders and
guide was first published as a separate, stand-alone standard in
1995 because of its applicability in preparing powder samples
for analysis by other methods (for example, Test Methods
This practice is under the jurisdiction of ASTM Committee B09 on Metal
B761andB822),inadditiontoTestMethodB430.Information
Powders and Metal Powder Productsand is the direct responsibility of Subcommit-
tee B09.03 on Refractory Metal Powders.
Current edition approved June 1, 2008. Published October 2008. Originally
approved in 1995. Last previous edition approved in 2003 as B859 – 03. DOI:
10.1520/B0859-03R08E01. Available from ASTM International Headquarters. Order Adjunct No.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or ADJB0859.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Michaels, A. I., “Turbidimetric Particle Size Distribution Theory: Application
Standards volume information, refer to the standard’s Document Summary page on to Refractory Metal and Oxide Powders,” 1958 Symposium on Particle Size
the ASTM website. Measurement, ASTM STP 234, ASTM, 1959, pp. 207–244.
*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
´1
B859 − 03 (2008)
onthedevelopmentandestablishmentofthemillingconditions 6. Procedure
here specified can be found in the footnoted reference.
6.1 Place 30 6 0.1 g of tungsten, molybdenum, rhenium, or
4.3 The milling procedure described in this practice does
tantalummetal,or50 60.1goftungstencarbidepowderinthe
not necessarily break down only agglomerates without fractur- milling bottle containing the 50 tungsten milling rods.
ing individual particles; some particle fracture may occur in
6.2 Seal the milling bottle and rotate on the jar roll mill for
certain powders. However, use of this practice does provide
60 min6 15 s at a bottle speed of 145 6 5 rpm.After the first
consistent particle si
...


This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it 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 current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation:B859–95 (Reapproved 2000) Designation:B859–03 (Reapproved 2008)
Standard Practice for
De-Agglomeration of Refractory Metal Powders and Their
Compounds Prior to Particle Size Analysis
This standard is issued under the fixed designation B 859; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
´ NOTE—Editorial changes were made in October 2008.
1. Scope*
1.1 This practice covers the de-agglomeration of refractory metal powders and their compounds in preparation for particle size
analysis.
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 metal powders (for example, elemental metals, carbides, and
nitrides) may be prepared for particle size analysis using this practice with caution as to effectiveness until actual satisfactory
experience is developed.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use. For specific precautionary statements, see Note 2.
2. Referenced Documents
2.1 ASTM Standards:
B 243 Terminology of Powder Metallurgy
B 330Test Method for Average Particle Size of Powders of Refractory Metals and Their Compounds by the Fisher Sub-Sieve
Sizer Test Method for Fisher Number of Metal Powders and Related Compounds
B 430 Test Method for Particle Size Distribution of Refractory Metal Powders and Related Compounds by Turbidimetry
B 761 Test Method for Particle Size Distribution of Refractory MetalsMetal Powders and TheirRelated Compounds by X-Ray
Monitoring of Gravity Sedimentation
B 821 Guide for Liquid Dispersion of Metal Powders and Related Compounds for Particle Size Analysis
B 822Test Method for Particle Size Distribution of Metal Powders and Related Compounds by Light Scattering Test Method
for Particle Size Distribution of Metal Powders and Related Compounds by Light Scattering
2.2 ASTM Adjunct:
ADJB0859 Detailed Drawings of Alternative Steel Milling Bottles
3. Terminology
3.1 Definitions—Definitions of powder metallurgy terms can be found in Terminology B 243.
4. Significance and Use
4.1 Refractory metal powders, such as tungsten and molybdenum, are usually produced by hydrogen reduction at high
temperatures. Thus, they usually contain numerous large, strongly-sintered agglomerates. Many of the manufacturing processes
using these powders involve a milling step or some similar treatment or depend on the individual particulate size, not on the
This practice is under the jurisdiction ofASTM Committee B-9 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.03
on Refractory Metal Powders.
Current edition approved Jan. 15, 1995. Published March 1995.
This practice is under the jurisdiction ofASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.03
on Refractory Metal Powders.
Current edition approved June 1, 2008. Published October 2008. Originally approved in 1995. Last previous edition approved in 2003 as B 859 – 03.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 02.05.volume information, refer to the standard’s Document Summary page on the ASTM website.
Michaels,A. I., “Turbidimetric Particle Size Distribution Theory:Application to Refractory Metal and Oxide Powders,” 1958 Symposium on Particle Size Measurement,
ASTM STP 234, ASTM, 1959, pp. 207–244.
Available from ASTM International Headquarters. Order Adjunct No. ADJB0859.
*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.
´1
B859–03 (2008)
agglomeratesize. Thus,aknowledgeoftheindividualparticulatesizedistribution,nottheagglomeratesizedistribution,isusually
desiredfromaparticlesizeanalysisofthesepowders.Thispracticeprovidesaprocedureforbreakingdownagglomeratesintotheir
constituent particles (de-agglomeration), without excessive fracture of the individual particles. The procedure is often referred to
as laboratory milling or rod milling.
4.2 The laboratory milling conditions specified in this guide have been in use since 1965 as part of Test Method B 430. This
guide was first published as a separate, stand-alone standard in 1995 because of its applicability in preparing powder samples for
analysis by other methods (for example, Test Methods B 761 and B 822), in addition to Test Method B 430. Information on the
development and establishment of the milling conditions here specified can be found in the footnoted reference.
4.3 The milling procedure described in this practice does not necessarily break down only agglomerates without fracturing
individual particles; some particle fracture may occur in certain powders. However, use of this practice does provide consistent
particle 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 listed in 1.1, when an
evaluation of the individual particulate size distribution is required from the subsequent particle size analysis. It shall not be used
when the agglomerate (as-is or as-supplied) size dist
...

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