ASTM C925-79(2000)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:C925–79(Reapproved2000)
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.
1. Scope
1.1 Thistestmethodcoversthedeterminationoftheparticle
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
frames, having nominal apertures of 45, 30, 20, 10, and 5 µm
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
5.2.1 Filtering Flask (suction flask), 1-L, with side arm,
funnel, two-hole to fit the graduate,
5.2.6 Quantity of glass tubing and rubber tubing,
1 5.2.7 Metal Rod, 15 to 20-cm, about 5 mm in diameter, and,
This test method is under the jurisdiction of ASTM Committee C-21 on
5.2.8 Vacuum Source.
Ceramic Whitewares and Related Products and is the direct responsibility of
Subcommittee C21.07 on Nonplastics.
5.3 Ultrasonic Cleaner, required to clean all sieves below
Current edition approved Dec. 28, 1979. Published February 1980.
20 µm. It should be low-powered (for example, 100 W).
Annual Book of ASTM Standards, Vol 14.02.
5.4 AnalyticalBalance,capableofweighingupto100gand
Asupport grid, manufactured by Buckbee Mears Co., 245 E. Sixth St., St. Paul,
MN 55101, has been found satisfactory for this purpose. having at least three significant digits after the decimal.
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C925
5.5 Drying Oven, capable of maintaining 110 6 5°C. agent), and disperse by placing beaker in ultrasonic bath for 1
5.6 Desiccator, containing magnesium perchlorate or other min. Microscopical examination of the particles after disper-
suitable desiccant. sion may be helpful in determining if the dispersion is
complete.
6. Reagents and Materials
10.4 Wash the dispersed sample onto the sieve using a wash
6.1 Water, visually clear and particle free, not necessarily
bottle containing the sieving solution, turn on vacuum (a
distilled, at room temperature or slightly above. maximum of 15 in. of water), and agitate. Continuously add
6.2 Sieving Solution, a dispersing media consisting of 0.1
sieving solution, at a rate sufficient to maintain a small amount
weight % solution of sodium hexametaphosphate or sodium inthesieve,untilabout1Lhaspassed.Below6µmtheamount
pyrophosphate in water.
of liquid required is less due to the time for sieving.Agitate by
6.3 Drying Agents, acetone or methyl alcohol, commercial sharp tapping on the sieve frame with the metal rod. For sieves
grade.
above30µmtheliquidrunsquicklyenoughwithoutvacuumso
that the air-bleed valve can be opened. The bleed-line should
7. Sampling
be pinched occasionally, however, to draw the larger particles
7.1 Since the amount of sample used in the determination is
through, but care must be taken to avoid damage to the sieve.
quite small, great care must be taken to avoid segregation.
For apertures of 10 µm or less, when
...