ASTM B761-02e1
(Test Method)Standard Test Method for Particle Size Distribution of Metal Powders and Related Compounds by X-Ray Monitoring of Gravity Sedimentation
Standard Test Method for Particle Size Distribution of Metal Powders and Related Compounds by X-Ray Monitoring of Gravity Sedimentation
SCOPE
1.1 This test method covers the determination of particle size distributions of metal powders. Experience has shown that this test method is satisfactory for the analysis of elemental tungsten, tungsten carbide, molybdenum, and tantalum powders, all with an as-supplied Fisher number of 6 m or less, as determined by Test Method B 330. Other metal powders (for example, elemental metals, carbides, and nitrides) may be analyzed using this test method with caution as to significance until actual satisfactory experience is developed (see 7.2). The procedure covers the determination of particle size distribution of the powder in the following two conditions:
1.1.1 As the powder is supplied (as-supplied), and
1.1.2 After the powder has been deagglomerated by rod milling as described in Practice B 859.
1.2 This test method is applicable to particles of uniform density and composition having a particle size distribution range of 0.1 up to 100 μm.
1.2.1 However, the relationship between size and sedimentation velocity used in this test method assumes that particles sediment within the laminar flow regime. This requires that the particles sediment with a Reynolds number of 0.3 or less. Particle size distribution analysis for particles settling with a larger Reynolds number may be incorrect due to turbulent flow. Some materials covered by this test method may settle with Reynolds number greater than 0.3 if particles greater than 25 m are present. The user of this test method should calculate the Reynolds number of the largest particle expected to be present in order to judge the quality of obtained results. Reynolds number (Re) can be calculated using the flowing equation
Re = D3(ρ - ρ 0ρog
/18π2
where
D = the diameter of the largest particle expected to be present,
ρ = the particle density,
ρ0 = the suspending liquid density,
g = the acceleration due to gravity, and
π = is the suspending liquid viscosity.
A table of the largest particles that can be analyzed with Reynolds number of 0.3 or less in water at 35°C is given for a number of metals in Table 1. A column of the Reynolds number calculated for a 30-μm particle sedimenting in the same liquid system is given for each material also.
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. Specific hazard information is given in Section 7.
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Designation:B761–02
Standard Test Method for
Particle Size Distribution of Metal Powders and Related
1
Compounds by X-Ray Monitoring of Gravity Sedimentation
This standard is issued under the fixed designation B 761; 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 (e) indicates an editorial change since the last revision or reapproval.
1
e NOTE—Section 11.1.1 was editorially corrected in November 2004.
1. Scope*
where
1.1 This test method covers the determination of particle
size distributions of metal powders. Experience has shown that
this test method is satisfactory for the analysis of elemental
D = the diameter of the largest particle expected to be
tungsten, tungsten carbide, molybdenum, and tantalum pow-
present,
ders, all with an as-supplied Fisher number of 6 µm or less, as
r = the particle density,
determined by Test Method B 330. Other metal powders (for r = the suspending liquid density,
0
g = the acceleration due to gravity, and
example, elemental metals, carbides, and nitrides) may be
h = is the suspending liquid viscosity.
analyzed using this test method with caution as to significance
until actual satisfactory experience is developed (see 7.2). The
A table of the largest particles that can be analyzed with
procedure covers the determination of particle size distribution
Reynolds number of 0.3 or less in water at 35°C is given for a
of the powder in the following two conditions:
numberofmetalsinTable1.AcolumnoftheReynoldsnumber
1.1.1 As the powder is supplied (as-supplied), and
calculated for a 30–µm particle sedimenting in the same liquid
1.1.2 After the powder has been deagglomerated by rod
system is given for each material also.
milling as described in Practice B 859.
1.3 This standard does not purport to address all of the
1.2 This test method is applicable to particles of uniform
safety concerns, if any, associated with its use. It is the
density and composition having a particle size distribution
responsibility of the user of this standard to establish appro-
range of 0.1 up to 100 µm.
priate safety and health practices and determine the applica-
1.2.1 However, the relationship between size and sedimen-
bility of regulatory limitations prior to use. Specific hazard
tation velocity used in this test method assumes that particles
information is given in Section 7.
sediment within the laminar flow regime.This requires that the
particles sediment with a Reynolds number of 0.3 or less.
2. Referenced Documents
Particle size distribution analysis for particles settling with a
2
2.1 ASTM Standards:
largerReynoldsnumbermaybeincorrectduetoturbulentflow.
B 330 Test Method for Fisher Number of Metal Powders
Some materials covered by this test method may settle with
and Related Compounds
Reynolds number greater than 0.3 if particles greater than 25
B 821 Guide for Liquid Dispersion of Metal Powders and
µm are present. The user of this test method should calculate
Related Compounds for Particle Size Analysis
the Reynolds number of the largest particle expected to be
B 859 Practice for De-Agglomeration of Refractory Metal
present in order to judge the quality of obtained results.
Powders and Their Compounds Prior to Particle Size
Reynolds number (Re) can be calculated using the flowing
Analysis
equation
E 456 Terminology Related to Quality and Statistics
3
D ~r – r !r g
0 0
E 691 Practice for Conducting an Interlaboratory Study to
Re 5 (1)
2
18h
Determine the Precision of a Test Method
1
This test method is under the jurisdiction of ASTM Committee B09 on Metal
2
Powders and Metal Powder Products and is the direct responsibility of Subcom- For referenced ASTM standards, visit the ASTM website, www.astm.org, or
mittee B09.03 on Refractory Metal Powders. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Nov. 10, 2002. Published December 2002. Originally Standards volume information, refer to the standard’s Document Summary page on
approved in 1986. Last previous edition approved in 1998 as B 761 – 98. 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.
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B761–02
TABLE 1 Maximum Diameter of Metal Powders and Related Compounds That Can Be Analyzed with Reynolds Number of 0.3 or Less in
Waterat35°C
A
Particle Composition Particle Density Maximum Particle Diameter Reynolds Number for 30 µm
Cobalt 8.90 33.19 0.22
Copper 8.92 33.16 0.22
Iron 7.86 34.79 0.19
Molybdenum 10.20 31.55 0.26
Nickel 8.90 33.19 0.22
Tantalum 16.
...
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