ASTM B430-97(2006)e1
(Test Method)Standard Test Method for Particle Size Distribution of Refractory Metal Powders and Related Compounds by Turbidimetry (Withdrawn 2011)
Standard Test Method for Particle Size Distribution of Refractory Metal Powders and Related Compounds by Turbidimetry (Withdrawn 2011)
SCOPE
1.1 This test method covers the determination of particle size distribution of refractory metal powders with a turbidimeter (). Experience has shown that this test method is satisfactory for the analysis of elemental tungsten, molybdenum, rhenium, tantalum metal powders, and tungsten carbide powders. Other refractory 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. The procedure covers the determination of particle size distribution of the powder in two conditions:
1.1.1 As the powder is supplied (as-supplied), and
1.1.2 After the powder has been de-agglomerated by rod milling (laboratory milled) according to Practice B 859.
1.2 Where dual units are given, inch-pound units are to be regarded as standard.
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.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:B430–97(Reapproved 2006)
Standard Test Method for
Particle Size Distribution of Refractory Metal Powders and
Related Compounds by Turbidimetry
This standard is issued under the fixed designation B430; 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.
This standard has been approved for use by agencies of the Department of Defense.
´ NOTE—Multiple source footnotes were removed editorially in May 2006.
1. Scope B859 Practice for De-Agglomeration of Refractory Metal
Powders and Their Compounds Prior to Particle Size
1.1 This test method covers the determination of particle
Analysis
size distribution of refractory metal powders with a turbidime-
2 E456 Terminology Relating to Quality and Statistics
ter (1). Experience has shown that this test method is
E691 Practice for Conducting an Interlaboratory Study to
satisfactory for the analysis of elemental tungsten, molybde-
Determine the Precision of a Test Method
num, rhenium, tantalum metal powders, and tungsten carbide
2.2 ASTM Adjunct:
powders. Other refractory metal powders, for example, el-
Turbidimeter (6 dwgs)
emental metals, carbides, and nitrides, may be analyzed using
this test method with caution as to significance until actual
3. Summary of Test Method
satisfactory experience is developed. The procedure covers the
3.1 Auniform dispersion of the powder in a liquid medium
determination of particle size distribution of the powder in two
is allowed to settle in a glass cell. A beam of light is passed
conditions:
through the cell at a level having a known vertical distance
1.1.1 As the powder is supplied (as-supplied), and
from the liquid level. The intensity of the light beam is
1.1.2 After the powder has been de-agglomerated by rod
determined using a photo cell. This intensity increases with
milling (laboratory milled) according to Practice B859.
time as sedimentation of the dispersion takes place.
1.2 Where dual units are given, inch-pound units are to be
3.2 The times at which all particles of a given size have
regarded as standard.
settled below the level of the transmitted light beam are
1.3 This standard does not purport to address all of the
calculated from Stokes’ law for the series of sizes chosen for
safety concerns, if any, associated with its use. It is the
the particle size analysis.
responsibility of the user of this standard to establish appro-
3.3 The intensity of the light beam at these times is
priate safety and health practices and determine the applica-
measured as percent of the light transmitted through the cell
bility of regulatory limitations prior to use.
with the clear liquid medium. The size distribution in the
2. Referenced Documents powder can be calculated from these relative intensities using
the Lambert-Beer law in the modified form (also see Refs 2, 3,
2.1 ASTM Standards:
4).
B330 TestMethodforFisherNumberofMetalPowdersand
Related Compounds DW 5 d ~log I 2 log I ! (1)
1–2 m d1 d2
B821 Guide for Liquid Dispersion of Metal Powders and
where I and I are the intensities measured at the times
d1 d2
Related Compounds for Particle Size Analysis
when all particles having diameters larger than d and d
1 2
respectively have settled below the level of the light beam, d
m
1 is the arithmetic mean of particle sizes d and d , and DW
1 2 1-2
This test method is under the jurisdiction of ASTM Committee B09 on Metal
refers to the relative weight for the particle size range between
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.03 on Refractory Metal Powders.
d and d .Values of DW are determined for each of the particle
1 2
Current edition approved April 1, 2006. Published May 2006. Originally
size ranges chosen. The sum of these values is (DW. The
´1
approved in 1965. Last previous edition approved in 2001 as B430 – 97 (2001) .
weight percent of particles in the size range from d to d can
DOI: 10.1520/B0430-97R06E01. 1 2
The boldface numbers in parenthesis refer to the references listed at the end of then be calculated as:
this test method.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Copies of detailed drawings of an acceptable instrument are available from
Standards volume information, refer to the standard’s Document Summary page on ASTM International Headquarters. OrderAdjunct No.ADJB0430. Original adjunct
the ASTM website. produced in 1966.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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B430–97 (2006)
Weight, % 5 ~DW /(DW! 3 100 (2) 7. Preparation of Apparatus
7.1 Warm up equipment by turning on the light source and
4. Significance and Use
recorder for a minimum of 1 h prior to use.
4.1 Knowledge of the particle size distribution of refractory
7.2 Fill the cell with sedimentation medium to a height
metal powders is useful in predicting powder-processing be-
sufficient to cover the light beam path by at least 10 mm and
havior, and ultimate performance of powder metallurgy parts.
place the cell in the turbidimeter (Note 3). If a microammeter
Particle size distribution is closely related to the flowability,
is used to measure light intensity, adjust the light transmission
compressibility, and die-filling characteristics of a powder, as
to 100 % using the diaphragm. If a millivolt recorder is used,
wellastothefinalstructureandpropertiesofthefinishedparts.
adjust the potentiometer so that the photovoltaic cell output is
However, the degree of correlation between the results of this
10 mV or 100 %. In this case, the diaphragm is not adjusted
testmethodandthequalityofpowdersinusehasnotbeenfully
and is completely open.
determined quantitatively.
NOTE 3—For convenience in filling the cell to the proper height,
4.2 This test method is suitable for manufacturing control
inscribe a line on each face of the cell at the desired liquid-level height.
and research and development in the production and use of
The height of fall is usually 25 mm. To determine the location of the line,
refractory metal-type powders, as indicated in 1.1.
the center of the light beam path must be established and 25 mm added to
4.3 Reportedparticlesizemeasurementisafunctionofboth
this value.
the actual particle dimension and shape factor, as well as the
7.3 After the instrument is adjusted to 100 % light transmis-
particular physical or chemical properties being measured.
sion through the sedimentation cell and medium, move the cell
Caution is required when comparing data from instruments
carriage until light is passing through a reference glass held in
operating on different physical or chemical parameters or with
another slot of the cell carriage. Read and record the percent of
different particle size measurement ranges. Sample acquisition,
reference light transmission. Having been selected to have
handling, and preparation also can affect reported particle size
approximately 70 to 95 % of the transmission of the sedimen-
results.
tation cell and medium, the reference glass will indicate 100 %
light transmission through the sedimentation cell when the
5. Apparatus
recorder reads this value through the reference cell.
5.1 Turbidimeter(5)—Therecommendedinstrumentisone
using a cell rectangular in cross section, approximately 50 mm
8. Calculation of Times at Which Light Intensity is
high, 40 mm wide, and 10-mm sedimentation medium thick-
Measured
ness, and having optically parallel faces.
8.1 The times at which the light transmission values should
5.2 Millivolt Recorder, 0 to 10-mV range, 10-in. (254-mm)
be read are calculated from Stokes’ law. A uniform 1-µm
wide strip chart, 0 to 100 graduations, 120 in./h (50 mm/min)
interval should be used in making measurements through the
chartspeed,ormicroammeterwith0to100graduations,15-µA
10-µm size and, depending upon the particular powder, either
full scale, 4.5-mV full scale.
1-µm or 5-µm intervals thereafter. The form of Stokes’ law
NOTE 1—While a 120-in./h (50-mm/min) chart speed is recommended, used is as follows:
other speeds may be satisfactory.
8 2
t 5 ~18 3 10 Nh!/d ~r 2r !g (3)
x m
5.3 Ultrasonic Cleaning Tank, with tank dimensions ap-
where:
proximately 5 by 5 by 3 in. (127 by 127 by 76 mm) deep and
1 1 5 t = time, s,
an output of 50 W, or approximately 3 ⁄2 by 3 ⁄2 by 2 ⁄8 in. (89
N = viscosity of settling medium at ambient temperature,
by 89 by 67 mm) deep and an output of 25 W.
P(Note 4),
5.4 Glass Vial, nominal 2-dram, flat-bottom, with a tight-
h = height of fall, cm (distance from liquid level height
fitting cap. The vial shall be approximately 2 in. (51 mm) in
to midpoint of light beam),
height with a ⁄8-in. (16-mm) outside diameter and approxi-
d = diameter of particle, µm (d , d , et al),
1 1 2
mately a ⁄32-in. (0.8-mm) wall.
r = theoretical density of the powder being tested (for
x
tungsten, use 19.3 g/cm ),
6. Reagents
r = density of settling medium at ambient temperature
m
6.1 Sedimentation Medium:
(Note 4), and
6.1.1 Base Medium, distilled or deionized water (see Note 2
g = gravitational constant (980 cm/s ).
4).
NOTE 4—Theviscosityanddensityvaluesatdifferenttemperaturesthat
6.1.2 Use either one of the following as recommended in
are used for the sedimentation medium in this procedure are the same as
Guide B821:
for pure water. Some viscosity (from the Handbook of Chemistry and
6.1.2.1 Daxad (No. 11)—Dissolve 25 mg in 1 L of base
Physics, 65th Edition, CRC Press, 1984) and density (from Metrological
medium.
Handbook 145, NIST, 1990) values are given as follows:
6.1.2.2 Sodium Hexametaphosphate—Dissolve 0.1 g in 1 L
Temperature, Viscosity, Density,
of base medium. °C °F cP g/cm
NOTE 2—Use water that is pure. Do not store the sedimentation
18 64.4 1.0530 0.9986
medium longer than a week, and do not use rubber tubing in any storage 19 66.2 1.0270 0.9984
20 68.0 1.0020 0.9982
container. Clean thoroughly all sedimentation medium containers every
21 69.8 0.9779 0.9980
week.
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B430–97 (2006)
10.2 The 5-min ultrasonic treatment dispersion procedure is
22 71.6 0.9548 0.9978
23 73.4 0.9325 0.9975
as follows:
24 75.2 0.9111 0.9973
10.2.1 Fill the vial with 2 mL of sedimentation medium or
25 77.0 0.8904 0.9970
to a height of approximately ⁄4 in. (7.0 mm). Add weighed
26 78.8 0.8705 0.9968
27 80.6 0.8513 0.9965
amount of powder and cap the vial. Place into the ultrasonic
28 82.4 0.8327 0.9962
tank, handholding the vial for 5 min.
29 84.2 0.8148 0.9959
30 86.0 0.7975 0.9956
NOTE 8—Depth of the liquid in the tank should be 1 ⁄2 to 2 in.
(approximately 40 to 50 mm) from the bottom. Liquid in the tank is
9. Conditioning (or De-agglomeration) of the Powder
distilled or deionized water, room temperature, with a small amount of
Prior to Analysis
detergent. A 1-min warm-up of the ultrasonic tank is recommended prior
9.1 Foras-suppliedparticlesizedistributiondeterminations, to vial immersion.
this step is not needed.
NOTE 9—If any of the powder sample is on the walls of the vial, the
liquid may be swirled before and during the ultrasonic treatment to rinse
9.2 For laboratory-milled particle size distribution determi-
thepowderdownintothebottom.Thevialneednotbeheldinastationary
nations, follow the procedure specified in Practice B859.
positionnorperpendiculartothebottom.Depthofimmersionandlocation
NOTE 5—Since milled powder has a greater tendency than as-supplied
of the vial are generally at the center portion of the tank, but may vary.
powder to pick up moisture and oxidize, the analysis procedure should be
Where cavitation within the vial is noticeable, as evidenced by rapid
initiated immediately after milling is completed. This is particularly
agitation of the powder dispersion, the bottom of the vial could even be at
important if the powder is to be dispersed using the 5-min hand-shake
the surface of the tank liquid. Agitation within the vial should be
procedure (see Section 8) where a difference can be seen between
noticeable. Where agitation is not evident within the vial, the vial should
determinationsmadeinsuccessiononpowdershavingsignificantamounts
be moved until agitation is evident. The vial generally is immersed to a
of 1-µm size powder. This difference, related to the size of the powder, is
depth where powder dispersion is at or below tank liquid level with the
greater for fine powders. For all practical purposes, however, two runs can 1
vial bottom not closer than ⁄2 in. (about 10 mm) to the bottom of the tank.
be made in succession on each milled powder. If more than two runs on
Immersionisgenerallynotwithin1in.(about25mm)fromanytankwall.
the same milled powder are desired using the 5-min shake procedure,
During ultrasonic treatment, a slight tingling feeling at the fingertips,
provisions may be taken to lessen (elimination is not possible) the effect
where they touch the vial, might be present.Also, while vial and contents
of humidity on the milled powder such as immediate splitting of the
are slightly warmed during treatment, no temperature correction need be
sample and storage under dry nitrogen or in a desiccator. If the 5-min
made because of the subsequent dilution in the sedimentation cell.
ultrasonicprocedureisusedtodispersethepowderforanalysis,themilled
10.2.2 Wipe dry or rinse the outside of the vial immediately
powdermaybestoredforseveraldayswithoutanyeffectbeingseeninthe
distribution results. after ultrasonic treatment to prevent ultrasonic tank liquid
contamination in the sedimentation cell.
10. Dispersion
10.2.3 Quantitatively transfer the powder dispersion into an
10.1 The powder, either as supplied, or laboratory milled in
empty sedimentation cell. Thoroughly rinse the vial, making
accordance with 9.2, may be dispersed in the sedimentation
sure that all the powder is in the cell.
medium either by a 5-min ultrasonic treatment procedure or by
NOTE 10—A250 or 500-mL plastic wash bottle that has had the nozzle
a 5-min continuous hand-shake procedure. The 5-min ultra-
straightened to an upright position has been found to be convenient to
sonic treatment procedure is the preferred and recommended
flush the vial of remaining traces of powder as it is inverted over and into
procedure.
the sedimentation cell at a slight angle. Care must be taken not to flush the
vialsostronglythatliquidandpowdersplashesoutoverthesedimentation
NOTE 6—The weight of the sample used should give a preferred initial
cell. (See Note 2 regarding cleansing of this equipment.)
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