ASTM C925-79(1995)e1

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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e1
Designation: C 925 – 79 (Reapproved 1995)
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
Precision Electroformed Wet Sieve Analysis of Nonplastic
Ceramic Powders
This standard is issued under the fixed designation C 925; 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.
e NOTE—Section 13 was added editorially in May 1995.
1. Scope
1.1 This test method covers the determination of the particle
size distribution of pulverized alumina and quartz for particle
sizes from 45 to 5 μm by wet sieving.
1.2 This standard does not purport to address the safety
concerns 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 limita-
tions prior to use.
2. Referenced Documents
2.1 ASTM Standards:
E 161 Specification for Precision Electroformed Sieves
(Square Opening Series)
3. Summary of Test Method
3.1 A separate dispersed suspension of the powder is wet
sieved through each sieve, using vacuum and vibration. The
sieve and sample are dried and weighed.
4. Significance and Use
4.1 Both suppliers and users of pulverized ceramic powders
will find this test method useful to determine particle size
distributions for materials specifications, manufacturing con-
trol, development, and research.
4.2 The test method is simple, although tedious, uses
inexpensive equipment, and will provide a continuous curve
with data obtained with standardized woven sieves.
5. Apparatus
FIG. 1 Wet Sieving Apparatus
5.1 Precision Electroformed Sieves, 3-in., mounted in brass
5.2.1 Filtering Flask (suction flask), 1-L, with side arm,
frames, having nominal apertures of 45, 30, 20, 10, and 5 μm
3 5.2.2 Büchner Funnel (for example, Coors No. 2),
and a support grid having 5.7 lines per centimetre. Interme-
5.2.3 O-Ring, 7.5-cm, rubber,
diate sizes may also be used.
5.2.4 Graduate, 1-L,
5.2 Sieving Device (Fig. 1):
5.2.5 Rubber Stoppers, one-hole to fit the flask and the
funnel, two-hole to fit the graduate,
1 5.2.6 Quantity of glass tubing and rubber tubing,
This test method is under the jurisdiction of ASTM Committee C-21 on
Ceramic Whitewares and Related Products and is the direct responsibility of 5.2.7 Metal Rod, 15 to 20-cm, about 5 mm in diameter, and,
Subcommittee C21.07 on Nonplastics.
5.2.8 Vacuum Source.
Current edition approved Dec. 28, 1979. Published February 1980.
5.3 Ultrasonic Cleaner, required to clean all sieves below
Annual Book of ASTM Standards, Vol 14.02.
20 μm. It should be low-powered (for example, 100 W).
A support grid, manufactured by Buckbee Mears Co., 245 E. Sixth St., St. Paul,
MN 55101, has been found satisfactory for this purpose. 5.4 Analytical Balance, capable of weighing up to 100 g and
C 925
having at least three significant digits after the decimal. agent), and disperse by placing beaker in ultrasonic bath for 1
5.5 Drying Oven, capable of maintaining 110 6 5°C. min. Microscopical examination of the particles after disper-
5.6 Desiccator, containing magnesium perchlorate or other sion may be helpful in determining if the dispersion is
suitable desiccant. complete.
10.4 Wash the dispersed sample onto the sieve using a wash
6. Reagents and Materials
bottle containing the sieving solution, turn on vacuum (a
6.1 Water, visually clear and particle free, not necessarily
maximum of 15 in. of water), and agitate. Continuously add
distilled, at room temperature or slightly above.
sieving solution, at a rate sufficient to maintain a small amount
6.2 Sieving Solution, a dispersing media consisting of 0.1
in the sieve, until about 1 L has passed. Below 6 μm the amount
weight % solution of sodium hexametaphosphate or sodium
of liquid required is less due to the time for sieving. Agitate by
pyrophosphate in water.
sharp tapping on the sieve frame with the metal rod. For sieves
6.3 Drying Agents, acetone or methyl alcohol, commercial
above 30 μm the liquid runs quickly enough without vacuum so
grade.
that the air-bleed valve can be opened. The bleed-line should
be pinched occasionally, however, to draw the larger particles
7. Sampling
through, bu
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