ASTM B430-97(2001)e1
(Test Method)Standard Test Method for Particle Size Distribution of Refractory Metal Powders and Related Compounds by Turbidimetry
Standard Test Method for Particle Size Distribution of Refractory Metal Powders and Related Compounds by Turbidimetry
SCOPE
1.1 This test method covers the determination of particle size distribution of refractory metal powders with a turbidimeter (1). 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 B859.
1.2 Where dual units are given, inch-pound units are to be regarded as standard.
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.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
e1
Designation:B430–97 (Reapproved 2001)
Standard Test Method for
Particle Size Distribution of Refractory Metal Powders and
Related Compounds by Turbidimetry
This standard is issued under the fixed designation B 430; 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.
This standard has been approved for use by agencies of the Department of Defense.
e NOTE—Adjunct references were corrected editorially in April 2006.
1. Scope B 859 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 E 456 Terminology Relating to Quality and Statistics
ter (1). Experience has shown that this test method is
E 691 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 B 859.
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).
B 330 Test Method for Fisher Number of Metal Powders
and Related Compounds DW 5 d ~log I 2 log I ! (1)
1–2 m d1 d2
B 821 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
is the arithmetic mean of particle sizes d and d , and DW
1 2 1-2
refers to the relative weight for the particle size range between
This test method is under the jurisdiction of ASTM Committee B09 on Metal
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.03 on Refractory Metal Powders.
Current edition approved Sept. 10, 1997. Published February 1998. Originally
published as B 430 – 65 T. Last previous edition B 430 – 95. The recommended instrument is a Cenco Photelometer (not made anymore) of
The boldface numbers in parenthesis refer to the references listed at the end of original or modified designs or any proven equivalent instrument. A schematic
this test method. diagram of the Photelometer is shown in the papers referenced at the end of this test
For referenced ASTM standards, visit the ASTM website, www.astm.org, or method. A fabricated instrument can be secured from WAB Instruments Co., 5171
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Hickory Dr., Cleveland, OH 44124. Copies of detailed drawings of an acceptable
Standards volume information, refer to the standard’s Document Summary page on instrumentareavailablefromASTMInternationalHeadquarters.OrderAdjunct No.
the ASTM website. ADJB0430. Original adjunct produced in 1966.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
e1
B430–97 (2001)
d and d .Values of DW are determined for each of the particle 6.1.1 Base Medium, distilled or deionized water (see Note
1 2
size ranges chosen. The sum of these values is (DW. The 4).
weight percent of particles in the size range from d to d can 6.1.2 Use either one of the following as recommended in
1 2
then be calculated as: Guide B 821:
6.1.2.1 Daxad (No. 11) —Dissolve 25 mg in 1 L of base
Weight, % 5 ~DW /(DW! 3 100 (2)
medium.
6.1.2.2 Sodium Hexametaphosphate—Dissolve 0.1 g in 1 L
4. Significance and Use
of base medium.
4.1 Knowledge of the particle size distribution of refractory
NOTE 2—Use water that is pure. Do not store the sedimentation
metal powders is useful in predicting powder-processing be-
medium longer than a week, and do not use rubber tubing in any storage
havior, and ultimate performance of powder metallurgy parts.
container. Clean thoroughly all sedimentation medium containers every
Particle size distribution is closely related to the flowability,
week.
compressibility, and die-filling characteristics of a powder, as
wellastothefinalstructureandpropertiesofthefinishedparts.
7. Preparation of Apparatus
However, the degree of correlation between the results of this
7.1 Warm up equipment by turning on the light source and
testmethodandthequalityofpowdersinusehasnotbeenfully
recorder for a minimum of 1 h prior to use.
determined quantitatively.
7.2 Fill the cell with sedimentation medium to a height
4.2 This test method is suitable for manufacturing control
sufficient to cover the light beam path by at least 10 mm and
and research and development in the production and use of
place the cell in the turbidimeter (Note 3). If a microammeter
refractory metal-type powders, as indicated in 1.1.
is used to measure light intensity, adjust the light transmission
4.3 Reportedparticlesizemeasurementisafunctionofboth
to 100 % using the diaphragm. If a millivolt recorder is used,
the actual particle dimension and shape factor, as well as the
adjust the potentiometer so that the photovoltaic cell output is
particular physical or chemical properties being measured.
10 mV or 100 %. In this case, the diaphragm is not adjusted
Caution is required when comparing data from instruments
and is completely open.
operating on different physical or chemical parameters or with
NOTE 3—For convenience in filling the cell to the proper height,
differentparticlesizemeasurementranges.Sampleacquisition,
inscribe a line on each face of the cell at the desired liquid-level height.
handling, and preparation also can affect reported particle size
The height of fall is usually 25 mm. To determine the location of the line,
results.
the center of the light beam path must be established and 25 mm added to
this value.
5. Apparatus
7.3 After the instrument is adjusted to 100 % light transmis-
5.1 Turbidimeter(5)—Therecommendedinstrumentisone
sion through the sedimentation cell and medium, move the cell
using a cell rectangular in cross section, approximately 50 mm
carriage until light is passing through a reference glass held in
high, 40 mm wide, and 10-mm sedimentation medium thick-
another slot of the cell carriage. Read and record the percent of
ness, and having optically parallel faces.
reference light transmission. Having been selected to have
5.2 Millivolt Recorder, 0 to 10-mV range, 10-in. (254-mm)
approximately 70 to 95 % of the transmission of the sedimen-
wide strip chart, 0 to 100 graduations, 120 in./h (50 mm/min)
tation cell and medium, the reference glass will indicate 100 %
chart speed, or microammeter with 0 to 100 graduations,
light transmission through the sedimentation cell when the
15-µA full scale, 4.5-mV full scale.
recorder reads this value through the reference cell.
NOTE 1—While a 120-in./h (50-mm/min) chart speed is recommended,
other speeds may be satisfactory.
8. Calculation of Times at Which Light Intensity is
Measured
5.3 Ultrasonic Cleaning Tank, with tank dimensions ap-
proximately 5 by 5 by 3 in. (127 by 127 by 76 mm) deep and 8.1 The times at which the light transmission values should
1 1 5
an output of 50 W, or approximately 3 ⁄2 by 3 ⁄2 by 2 ⁄8 in. (89
be read are calculated from Stokes’ law. A uniform 1-µm
by 89 by 67 mm) deep and an output of 25 W.
interval should be used in making measurements through the
5.4 Glass Vial, nominal 2-dram, flat-bottom, with a tight-
10-µm size and, depending upon the particular powder, either
fitting cap. The vial shall be approximately 2 in. (51 mm) in
1-µm or 5-µm intervals thereafter. The form of Stokes’ law
height with a ⁄8-in. (16-mm) outside diameter and approxi-
used is as follows:
mately a ⁄32-in. (0.8-mm) wall.
8 2
t 5 ~18 3 10 Nh!/d ~r 2r !g (3)
x m
6. Reagents
where:
t = time, s,
6.1 Sedimentation Medium:
N = viscosity of settling medium at ambient temperature,
P(Note 4),
The 69800-Q1, Model S, Type G, Speedomax W, or XL630 Series recorder as
made by the Leeds and Northrup Co., have been found satisfactory.
Ultrasonic tank Model Nos. 2 or 12 as made by Bransonic Instrument Co.,
Stamford, CT, have been found satisfactory. Daxad No. 11 powder as made by the W. R. Grace and Co., Polymers and
Two-dram Titeseal vials, as made by Chemical Rubber Co., Cleveland, OH, Chemicals Div., 62 Whittemore Ave., Cambridge, MA 02140, has been found
have been found satisfactory. satisfactory.
e1
B430–97 (2001)
10. Dispersion
h = height of fall, cm (distance from liquid level height
to midpoint of light beam),
10.1 The powder, either as supplied, or laboratory milled in
d = diameter of particle, µm (d , d , et al),
1 2
accordance with 9.2, may be dispersed in the sedimentation
r = theoretical density of the powder being tested (for
x
medium either by a 5-min ultrasonic treatment procedure or by
tungsten, use 19.3 g/cm ),
a 5-min continuous hand-shake procedure. The 5-min ultra-
r = density of settling medium at ambient temperature
m
sonic treatment procedure is the preferred and recommended
(Note 4), and
2 procedure.
g = gravitational constant (980 cm/s ).
NOTE 6—The weight of the sample used should give a preferred initial
NOTE 4—Theviscosityanddensityvaluesatdifferenttemperaturesthat
lighttransmissionofbetween20and30 %.Transmissionsbetween15and
are used for the sedimentation medium in this procedure are the same as
40 %areacceptable.Ifitisdesiredtochangetheinitiallighttransmission,
for pure water. Some viscosity (from the Handbook of Chemistry and
reweigh another sample, increasing or decreasing the weight accordingly.
Physics, 65th Edition, CRC Press, 1984) and density (from Metrological
Handbook 145, NIST, 1990) values are given as follows: NOTE 7—Table 1 gives likely sample weight ranges for lab-milled
tungsten powders having known Fisher sub-sieve sizer average particle
Temperature, Viscosity, Density,
diameters in the as-supplied condition. (See Test Method B 330.) These
°C °F cP g/cm
likely sample weight ranges apply for powders that have been lab-milled
18 64.4 1.0530 0.9986
before testing and either dispersed using the 5-min ultrasonic treatment or
19 66.2 1.0270 0.9984
the 5-min hand-shake procedure.The table also lists preferred micrometre
20 68.0 1.0020 0.9982
sizes to be read. For the determination of particle distribution of tungsten
21 69.8 0.9779 0.9980
in the as-supplied condition, or other powders, proper weights should be
22 71.6 0.9548 0.9978
23 73.4 0.9325 0.9975 determined by trial and error.
24 75.2 0.9111 0.9973
25 77.0 0.8904 0.9970 10.2 The 5-min ultrasonic treatment dispersion procedure is
26 78.8 0.8705 0.9968
as follows:
27 80.6 0.8513 0.9965
28 82.4 0.8327 0.9962 10.2.1 Fill the vial with 2 mL of sedimentation medium or
29 84.2 0.8148 0.9959
to a height of approximately ⁄4 in. (7.0 mm). Add weighed
30 86.0 0.7975 0.9956
amount of powder and cap the vial. Place into the ultrasonic
tank, handholding the vial for 5 min.
9. Conditioning (or De-agglomeration) of the Powder
Prior to Analysis
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
9.1 Foras-suppliedparticlesizedistributiondeterminations,
distilled or deionized water, room temperature, with a small amount of
this step is not needed.
detergent. A 1-min warm-up of the ultrasonic tank is recommended prior
9.2 For laboratory-milled particle size distribution determi-
to vial immersion.
nations, follow the procedure specified in Practice B 859.
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
NOTE 5—Since milled powder has a greater tendency than as-supplied
thepowderdownintothebottom.Thevialneednotbeheldinastationary
powder to pick up moisture and oxidize, the analysis procedure should be
positionnorperpendiculartothebottom.Depthofimmersionandlocation
initiated immediately after milling is completed. This is particularly
of the vial are generally at the center portion of the tank, but may vary.
important if the powder is to be dispersed using the 5-min hand-shake
Where cavitation within the vial is noticeable, as evidenced by rapid
procedure (see Section 8) where a difference can be seen between
agitation of the powder dispersion, the bottom of the vial could even be at
determinationsmadeinsuccessiononpowdershavingsignificantamounts
the surface of the tank liquid. Agitation within the vial should be
of 1-µm size powder. This difference, related to the size of the powder, is
noticeable. Where agitation is not evident within the vial, the vial should
greater for fine powders. For all practical purposes, however, two runs can
be moved until agitation is evident. The vial generally is immersed to a
be made in succession on each milled powder. If more than two runs on
depth where po
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.