ASTM C958-92(2007)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C958 − 92 (Reapproved2007)
Standard Test Method for
Particle Size Distribution of Alumina or Quartz by X-Ray
Monitoring of Gravity Sedimentation
This standard is issued under the fixed designation C958; 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 4. Summary of Test Method
1.1 This test method covers the determination of the particle 4.1 An aqueous homogeneous dispersion of the specimen is
size distribution of alumina or quartz powders in the range permitted to settle in a cell. The decrease in particle concen-
from 0.5 to 50 µm and having a median particle diameter from tration over a programmed settling distance is monitored by an
2.5 to 10 µm using a sedimentation method. This test method X-ray beam passing through the sedimenting dispersion to a
is one of several found valuable for the measurement of detector. The specimen concentration at any given sedimenta-
particle size. Instruments used for this test method employ a tion distance is inversely proportional to the X-ray flux and the
constant intensity X-ray beam that is passed through a sedi- equivalent diameter (spherical) is calculated from Stokes’ law.
menting dispersion of particles.
NOTE 1—Refer to Terminology C242. Most equipment manufacturers
refer to this as the equivalent spherical diameter.
1.2 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information
5. Apparatus
only.
5.1 X-Ray Sedimentation Apparatus.
1.3 This standard does not purport to address all of the
5.2 Ultrasonic Probe or Bath—Anultrasonicprobeapproxi-
safety concerns, if any, associated with its use. It is the
mately 13-mm ( ⁄2-in.) in diameter and approximately 50 to
responsibility of the user of this standard to establish appro-
100 W or an ultrasonic bath of approximately 0.3 W/cm (2
priate safety and health practices and determine the applica-
W/in. ).
bility of regulatory limitations prior to use. For specific hazard
statements, see Section 7.
6. Reagents
6.1 Purity of Reagents—Reagent grade chemicals shall be
2. Referenced Documents
used in all tests. Unless otherwise indicated, it is intended that
2.1 ASTM Standards:
all reagents shall conform to the specifications of the Commit-
C242 Terminology of Ceramic Whitewares and Related
tee onAnalytical Reagents of theAmerican Chemical Society,
Products
where such specifications are available. Other grades may be
E177 Practice for Use of the Terms Precision and Bias in
used, provided it is first ascertained that the reagent is of
ASTM Test Methods
sufficiently high purity to permit its use without lessening the
E691 Practice for Conducting an Interlaboratory Study to
accuracy of the determination.
Determine the Precision of a Test Method
6.2 Distilled or Deionized Water .
6.3 Dispersing Liquid—Dissolve 1.0 g/L of reagent grade
3. Terminology
sodium hexametaphosphate in distilled or deionized water.
3.1 For definitions of terms used in this test method, refer to
Discard any remaining solution after six weeks from date of
Terminology C242.
preparation.
7. Hazards
ThistestmethodisunderthejurisdictionofASTMCommitteeC21onCeramic
7.1 Precautions applying to the use of low-intensity X-rays
Whitewares and Related Productsand is the direct responsibility of Subcommittee
should be observed.
C21.04 on Raw Materials.
Current edition approved May 1, 2007. Published June 2007. Originally
approved in 1992. Last previous edition approved in 2000 as C958–92(2000) DOI: Reagent Chemicals, American Chemical Society Specifications, American
10.1520/C0958-92R07. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
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C958 − 92 (2007)
7.2 Users should be aware that sample concentrations used 8.7 Run the particle size distribution in the “Percent Finer
in this test method may be higher than those considered ideal Than” mode using a starting diameter of 50 µm. Calculate the
by some authorities and that the r
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