ASTM B859-21

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

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 agglomerate size.3 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.  
4.2 The laboratory milling conditions specified in this guide have been in use since 1965, initially as part of a particle size analysis test method. 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 as well (for example, Test Methods B761 and B822). Information on the development and establishment of the milling conditions here specified can be found in the footnoted reference.4  
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 1.2, 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 distr...
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 Units—With the exception of the values for mass, for which the use of the gram (g) unit is the long-standing industry practice, the values stated in SI units 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 responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Note 2.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2021
• ICS: 77.160 - Powder metallurgy
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.03 - Refractory Metal Powders

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B859 − 21
Standard Practice for
De-Agglomeration of Refractory Metal Powders and Their
1
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.
1. Scope* B330 Test Methods for Estimating Average Particle Size of
Metal Powders and Related Compounds Using Air Per-
1.1 This practice covers the de-agglomeration of refractory
meability
metal powders and their compounds in preparation for particle
B761 Test Method for Particle Size Distribution of Metal
size analysis.
Powders and Related Compounds by X-Ray Monitoring
1.2 Experience has shown that this practice is satisfactory
of Gravity Sedimentation
for the de-agglomeration of elemental tungsten, molybdenum,
B821 Guide for Liquid Dispersion of Metal Powders and
rhenium, and tantalum metal powders, and tungsten carbide.
Related Compounds for Particle Size Analysis
Other metal powders (for example, elemental metals, carbides,
B822 Test Method for Particle Size Distribution of Metal
and nitrides) may be prepared for particle size analysis using
Powders and Related Compounds by Light Scattering
this practice with caution as to effectiveness until actual
satisfactory experience is developed.
3. Terminology
1.3 Units—With the exception of the values for mass, for
3.1 Definitions—Definitions of powder metallurgy terms
which the use of the gram (g) unit is the long-standing industry
can be found in Terminology B243.
practice, the values stated in SI units are to be regarded as
standard. No other units of measure are included in this
4. Significance and Use
standard.
4.1 Refractory metal powders, such as tungsten and
1.4 This standard does not purport to address all of the
molybdenum, are usually produced by hydrogen reduction at
safety concerns, if any, associated with its use. It is the
high temperatures. Thus, they usually contain numerous large,
responsibility of the user of this standard to establish appro-
strongly-sintered agglomerates. Many of the manufacturing
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. processes using these powders involve a milling step or some
For specific precautionary statements, see Note 2. similar treatment or depend on the individual particulate size,
3
1.5 This international standard was developed in accor- not on the agglomerate size. Thus, a knowledge of the
dance with internationally recognized principles on standard- individual particulate size distribution, not the agglomerate
ization established in the Decision on Principles for the
size distribution, is usually desired from a particle size analysis
Development of International Standards, Guides and Recom- of these powders. This practice provides a procedure for
mendations issued by the World Trade Organization Technical
breaking down agglomerates into their constituent particles
Barriers to Trade (TBT) Committee.
(de-agglomeration), without excessive fracture of the indi-
vidual particles. The procedure is often referred to as labora-
2. Referenced Documents
tory milling or rod milling.
2
2.1 ASTM Standards:
4.2 The laboratory milling conditions specified in this guide
B243 Terminology of Powder Metallurgy
have been in use since 1965, initially as part of a particle size
analysis test method. This guide was first published as a
1
This practice is under the jurisdiction of ASTM Committee B09 on Metal
separate, stand-alone standard in 1995 because of its applica-
Powders and Metal Powder Products and is the direct responsibility of Subcom-
bility in preparing powder samples for analysis by other
mittee B09.03 on Refractory Metal Powders.
methods as well (for example, Test Methods B761 and B822).
Current edition approved April 1, 2021. Published May 2021. Originally
approvedin1995.Lastpreviouseditionapprovedin2018asB859–13(2018).DOI:
10.1520/B0859-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3
contact ASTM Customer Service at [e-mail]. 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
...

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. 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.
Designation: B859 − 13 (Reapproved 2018) B859 − 21
Standard Practice for
De-Agglomeration of Refractory Metal Powders and Their
1
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.
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 Units—With the exception of the values for mass, for which the use of the gram (g) unit is the long-standing industry practice,
the values stated in SI units 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 responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. For specific precautionary statements, see Note 2.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
B243 Terminology of Powder Metallurgy
B330 Test Methods for Estimating Average Particle Size of Metal Powders and Related Compounds Using Air Permeability
B761 Test Method for Particle Size Distribution of Metal Powders and Related Compounds by X-Ray Monitoring of Gravity
Sedimentation
B821 Guide for Liquid Dispersion of Metal Powders and Related Compounds for Particle Size Analysis
B822 Test Method for Particle Size Distribution of Metal Powders and Related Compounds by Light Scattering
2.2 ASTM Adjunct:
3
ADJB0859 Detailed Drawings of Alternative Steel Milling Bottles
1
This practice is under the jurisdiction of ASTM 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 April 1, 2018April 1, 2021. Published May 2018May 2021. Originally approved in 1995. Last previous edition approved in 20032018 as B859
– 13.13(2018). DOI: 10.1520/B0859-13R18.10.1520/B0859-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*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

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B859 − 21
3. Terminology
3.1 Definitions—Definitions of powder metallurgy terms can be found in Terminology B243.
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
3
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.
4.2 The laboratory milling conditions specified in this guide have been in use since 1965
...