ASTM C1282 - 08

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Designation: C 1282 – 08

Standard Test Method for

Determining the Particle Size Distribution of Advanced

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

1.1 This test method covers determination of the particle

size distribution of advanced ceramic powders speciﬁcally

silicon nitride and carbides, in the range of 0.1 to 20 µm,

having a median particle diameter from 0.5 to 5.0 µm.

1.2 The procedure described in this test method may be

applied successfully to other ceramic powders in this general

size range, provided that appropriate dispersion procedures are

developed. It is the responsibility of the user to determine the

applicability of this test method to other materials.

1.3 The values stated in SI units are to be regarded as the

standard. The values given in parentheses are for information

only.

1.4 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 appro-

priate safety and health practices and determine the applica-

bility of regulatory limitations prior to use.

2. Referenced Documents

2.1 ASTM Standards:

C 242 Terminology of Ceramic Whitewares and Related

Products

3. Terminology

3.1 Deﬁnitions—Refer to Terminology C 242 for deﬁnitions

of terms used in this test method.

4. Summary of Test Method

4.1 A homogeneous aqueous dispersion of the powder is

prepared. While kept in a thoroughly mixed condition, a small

aliquot is transferred to the analyzer sample cell, which is

placed in the instrument and subjected to a controlled centrifu-

gal acceleration at a known or controlled temperature. At

predetermined times related to the sedimentation of speciﬁc

Stokes’ diameters (Note 1), the optical absorbance is recorded

and compared to the initial value to determine the fraction of

the total sample that has sedimented a speciﬁc distance. A

volume-based size distribution is calculated from the

absorbance-time data. The results are reported as equivalent

diameter (spherical) (Note 2) since particles in these powders

are not truly spherical.

NOTE 1—This diameter in µm is referred to as Din the equation given

below.

NOTE 2—Refer to Terminology C 242 for the ASTM deﬁnition of this

term. Most equipment manufacturers refer to this as the equivalent

spherical diameter.

D25

18h·log X1

~ps–pf!u2t3108(1)

where:

h= viscosity of the ﬂuid, cP,

= distance from the middle of the centrifugal disc cell to the point

in the cell where sedimentation starts,

= distance from the center of the centrifugal disc cell to the point

where the light beam intersects the particle

t= time for the particle to settle, s

= particle density, g/cm

= ﬂuid density, g/cm

, and

u= rotational angular velocity, rad/s.

4.2 The instruments that have been found suitable for this

test method incorporate microcomputers that control instru-

ment operation and perform all required data acquisition and

computation functions.

5. Signiﬁcance and Use

5.1 Manufacturers and users of advanced ceramic powders

will ﬁnd this test method useful for determining the particle

size distribution of these materials for product speciﬁcation,

quality control, and research and development.

6. Apparatus

6.1 Centrifugal Particle Size Distribution Analyzer—The

analyzer shall incorporate a centrifuge capable of subjecting an

homogeneous dispersion of the sample to centrifugal accelera-

tion in specially designed sample cells. A collimated beam of

This test method is under the jurisdiction of ASTM Committee C28 on

Advanced Ceramics and is the direct responsibility of Subcommittee C28.03 on

Physical Properties and Performance.

Current edition approved Jan. 1, 2008. Published January 2008. Originally

approved in 1994. Last previous edition approved in 2006 as C 1282 – 00 (2006).

For referenced ASTM standards, visit the ASTM website, www.astm.org, or

contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM

Standards volume information, refer to the standard’s Document Summary page on

the ASTM website.

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visible light (either monochromatic or broad-band) shall

traverse the sample cell at a deﬁned distance from the top of the

cell. The change in photo-extinction resulting from sedimen-

tation of the sample shall be measured by a photo-detector and

appropriate electronic circuits and used to calculate the

volume-based size distribution of the sample.

6.2 Ultrasonic Probe, consisting of a 200 to 300-W power

unit, ultrasonic transducer, and 13-mm (

⁄

-in.) diameter probe.

6.3 Balance, top-loading, accurate to 10 60.1 g.

6.4 Stirrer, magnetic, with 25-mm (1-in.) and 19-mm (

⁄

in.) stirring bars.

6.5 Temperature measurement device (thermometer, ther-

mocouple, etc.), 0 to 50°C, accurate to 0.5°C.

6.6 Sample Cells, as supplied by the instrument manufac-

turer.

7. Reagents

7.1 Purity of Reagents—Reagent grade chemicals shall be

used in all tests. Unless otherwise indicated, it is intended that

all reagents shall conform to the speciﬁcations of the Commit-

tee on Analytical Reagents of the American Chemical Society,

where such speciﬁcations are available.

7.2 Darvan C

Dispersing Fluid—Dissolve 5.0 g Darvan C

(ammonium salt of polymethacrylic acid) in 95 cm

distilled

water (Note 3).

NOTE 3—These reagents are adequate to cover the range of samples up

to a maximum particle diameter of 20 µm.

7.3 pH Adjusters—Fresh ammonium hydroxide (NH4OH)

at 5 to 10 % strength is a common reagent used to raise pH

while fresh nitric acid (HNO3) at 5 to 10 % strength is a

common reagent to lower pH.

8. Procedure

8.1 Sample Preparation and Dispersion:

8.1.1 Add the appropriate sample mass of powder, usually 1

g, to 250 cm

dispersing medium in a 500-cm

beaker. The

dispersing medium consists of 250 cm

of distilled water to

which 0.3 g of dispersing liquid is added.

8.1.1.1 Sample Dispersion—Place the beaker containing

sample in an ice water bath so that the temperature of the

sample does not exceed approximately 30°C. Adjust the pH of

the sample to 9.060.2 to ensure adequate dispersion aided by

the chemical environment. Deagglomerate the sample by

inserting the ultrasonic transducer into the dispersing liquid/

sample in a beaker. Ensure that the transducer is approximately

10.0 mm above the bottom of the sample beaker. Apply the

ultrasonic energy at 40 W or higher for 1.0 min, and allow the

sample to settle for 1.0 min. Repeat this procedure three times

so that the total ultrasonic energy application time is 3 min.

This high level of mechanical energy application is necessary

to accomplish deagglomeration of the particles. The extent of

deagglomeration is expected to be different for powders

produced by different processes. An alternate approach is to

ultrasonicate for 3 min continuously before pH and tempera-

ture check. Readjust the pH, if necessary, after ultrasonic

application. Keep stirring the sample continuously, and test it

as soon as practical to prevent reagglomeration.

8.1.2 Add a 25-mm (1-in.) stirring bar to the beaker, and

place it on a magnetic stirrer. Stir for approximately 3 min in

a cold water bath to bring the sample to ambient temperature.

Continue stirring at constant temperature.

8.2 Analyzer Preparation:

8.2.1 To warm up the analyzer, apply power for a minimum

of 10 min prior to testing. Conduct the warmup with the sample

compartment closed. Make certain that the ventilation airﬂow

is not restricted by adjacent equipment, papers, or other

materials. Check the printer to ensure a sufficient supply of

paper exists. Clean a pair of sample cells and caps, rinse with

the 0.1 % Darvan C solution, and store inverted on absorbent

paper.

NOTE 4—The concentration of the sample may require dilution with

0.1 % Darvan C solution to meet the optical absorbance tolerance

speciﬁed in the instrument operating manual. Thorough mixing must

accompany any dilution of the sample.

8.2.2 If required by the manufacturer’s operating manual,

check and adjust the zero and full-scale settings. These

adjustments can be crucial to reliable and reproducible mea-

surements.

8.2.3 Input the test parameters (sample and ﬂuid density,

ﬂuid viscosity, test range, sedimentation distance, and centri-

fuge speed) according to the manufacturer’s operating manual.

Set the ﬂuid viscosity at the value corresponding to the actual

room temperature (see Table 1). Set the range such that the

volume percent greater than the maximum diameter is certainly

zero and the volume percent ﬁner than the minimum diameter

is less than 10 % (cumulative percent oversize greater than

90 %). Preliminary test runs may be required to establish the

range and the size of the divisions necessary to achieve the test

limits. The test range and division settings shall provide a

minimum of ten divisions within the test range.

8.2.4 If required by the manufacturer’s operating manual,

conduct a blank test with clean dispersant ﬂuid in the sample

and reference cells.

8.3 Test Performance:

8.3.1 Adjust the rate of the magnetic stirrer to produce a

slight vortex in the sample dispersion. Withdraw an appropriate

volume of sample from the center of the dilute dispersion with

a disposable plastic pipet. Make certain that the dispersion is

mixed thoroughly by vigorous pumping with the pipet (avoid

strong agitation, which would create bubbles). Completely

transfer the withdrawn sample to the drained sample cell. Insert

Reagent Chemicals, American Chemical Society Speciﬁcations , American

Chemical Society, Washington, DC. For suggestions on the testing of reagents not

listed by the American Chemical Society, see Reagent Chemicals and Standards,by

Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the United States

Pharmacopeia.

Darvan C is a trademarked product of R.T. Vanderbilt Company, Inc., Norwalk,

CT 06856-5150.

TABLE 1 Viscosity Coefficients of Water

Temperature, °C 20 21 22 23 24 25 26 27 28 29

Viscosity

coefficient,

mPa*s or cP

1.01 0.98 0.96 0.94 0.92 0.89 0.87 0.86 0.84 0.82

Viscosity coefficient values to two decimal places have been found satisfactory

for this test method.

C 1282 – 08

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the cell cap, carefully wipe all outer surfaces of the cell, place

in the centrifuge, and start the test. Monitor the absorbance

display on the instrument to ensure that the initial absorbance

is within the speciﬁed tolerance at the beginning of the test. If

not, refer to Note 4. When the test is completed, remove the

sample cell, clean immediately, and rinse with dispersant ﬂuid.

9. Presentation of Data

9.1 Analyzer Printout—The analyzers that have been found

suitable for this test method render data printouts that provide

a permanent record of the test conditions and graphic records

of the size distribution. These printouts may provide sufficient

information for many purposes.

10. Fluid Densities and Viscosity Coefficients

10.1 Table 1 lists the viscosity coefficients for water over the

temperature range of 20 to 29°C. Use these values for the

Darvan C solution. Use a density of 1.00 g/cm

for these

solutions.

11. Additional Data Presentations

11.1 The analyzers that have been found suitable for use

with this test method produce a printed report that may include

a cumulative size distribution table showing the volume

percent oversize, starting with the programmed maximum

diameter. The incremental divisions are selectable by the

operator in some operating modes and, in others, determined

by the microcomputer in the instrument.

12. Precision and Bias

12.1 Precision—No statement of precision can be made

since round-robin testing has not been completed.

12.2 Bias—It is not possible to discuss the bias of the results

obtained using this test method since no absolute method of

particle size distribution is recognized.

13. Keywords

13.1 advanced ceramics; particle size distribution;

photosedimentation

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned

in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk

of infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every ﬁve years and

if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards

and should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the

responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should

make your views known to the ASTM Committee on Standards, at the address shown below.

This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,

United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above

address or at 610-832-9585 (phone), 610-832-9555 (fax), or service@astm.org (e-mail); or through the ASTM website

(www.astm.org).

C 1282 – 08

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摘要：

ASTM C1282 - 08 是美国材料与试验协会（ASTM）发布的一项标准规范，全称为“Standard Specification for Polyolefin and Polyethylene (PE) and Polyvinyl Chloride (PVC) Sealing Tapes for Use in Conjunction with Insulation and Vapor Retarders”。该标准主要规定了用于建筑隔热层与防潮层配合使用的聚烯烃、聚乙烯及聚氯乙烯密封胶带的

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