ASTM C1282-94

NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn.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.
Designation: C 1282 – 94
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Determining the Particle Size Distribution of Advanced
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Ceramics by Centrifugal Photosedimentation
This standard is issued under the fixed designation C 1282; 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. Scope predetermined times related to the sedimentation of specific
Stokes’ diameters (Note 1), the optical absorbance is recorded
1.1 This test method covers determination of the particle
and compared to the initial value to determine the fraction of
size distribution of advanced ceramic powders specifically
the total sample that has sedimented a specific distance. A
silicon nitride and carbides, in the range of 0.1 to 20 μm,
volume-based size distribution is calculated from the
having a median particle diameter from 0.5 to 5.0 μm.
absorbance-time data. The results are reported as equivalent
1.2 The procedure described in this test method may be
diameter (spherical) (Note 2) since particles in these powders
applied successfully to other ceramic powders in this general
are not truly spherical.
size range, provided that appropriate dispersion procedures are
developed. It is the responsibility of the user to determine the
NOTE 1—This diameter in μm is referred to as D in the equation given
applicability of this test method to other materials.
below.
NOTE 2—Refer to Terminology C 242 for the ASTM definition of this
1.3 The values stated in SI units are to be regarded as the
term. Most equipment manufacturers refer to this as the equivalent
standard. The values given in parentheses are for information
spherical diameter.
only.
X
1.4 This standard does not purport to address all of the
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18 · log
h
X
safety concerns, if any, associated with its use. It is the 2 2 8
D 5 3 10 ()
2
~p – p !u t
responsibility of the user of this standard to establish appro-
s f
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
where:
h = viscosity of the fluid, cP,
2. Referenced Documents
X = distance from the middle of the centrifugal disc cell to
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2.1 ASTM Standards: the point in the cell where sedimentation starts,
X = distance from the center of the centrifugal disc cell to
C 242 Terminology of Ceramic Whitewares and Related
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2
the point where the light beam intersects the particle
Products
t = time for the particle to settle, s
E 177 Practice for Use of the Terms Precision and Bias in
3
3
r = particle density, g/cm ,
ASTM Test Methods s
3
r = fluid density, g/cm , and
f
E 691 Practice for Conducting an Interlaboratory Study to
3 u = rotational angular velocity, rad/s.
Determine the Precision of a Test Method
4.2 The instruments that have been found suitable for this
3. Terminology
test method incorporate microcomputers that control instru-
3.1 Definitions—Refer to Terminology C 242 for definitions
ment operation and perform all required data acquisition and
of terms used in this test method.
computation functions.
4. Summary of Test Method
5. Significance and Use
4.1 A homogeneous aqueous dispersion of the powder is
5.1 Manufacturers and users of advanced ceramic powders
prepared. While kept in a thoroughly mixed condition, a small
will find this test method useful for determining the particle
aliquot is transferred to the analyzer sample cell, which is
size distribution of these materials for product specification,
placed in the instrument and subjected to a controlled centrifu-
quality control, and research and development.
gal acceleration at a known or controlled temperature. At
6. Apparatus
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6.1 Centrifugal Particle Size Distribution Analyzer —The
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This test method is under the jurisdiction of ASTM Committee C-28 on
analyzer shall incorporate a centrifuge capable of subjecting an
Advanced Ceramics and is the direct responsibility of Subcommittee C28.05 on
Processing and Characterization.
Current edition approved Sept. 15, 1994. Published November 1994.
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Annual Book of ASTM Standards, Vol 15.02. Instruments from Horiba Instruments, Inc., 17671 Armstrong Ave., Irvine, CA
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Annual Book of ASTM Standards, Vol 14.02. 92714, have been found satisfactory. Other instruments may also be found suitable.
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C 1282
homogeneous dispersion of the sample to centrifugal accelera- after ultrasonic application. Keep stirring the sample continu-
tion in specially designed sample cells. A collimated beam of ously
...