ASTM C408-88(2016)
(Test Method)Standard Test Method for Thermal Conductivity of Whiteware Ceramics
Standard Test Method for Thermal Conductivity of Whiteware Ceramics
SIGNIFICANCE AND USE
2.1 This test method provides information useful in understanding and quantifying such parameters as thermal shock resistance and ability to conduct or dissipate heat.
SCOPE
1.1 This test method covers a general procedure2 for determining the thermal conductivity of whiteware ceramics over the temperature range from 100 to 300°F (40 to 150°C).
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI (metric) units given in parentheses are for information purposes only.
1.3 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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: C408 − 88 (Reapproved 2016)
Standard Test Method for
1
Thermal Conductivity of Whiteware Ceramics
This standard is issued under the fixed designation C408; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 3.1.1 Heating Unit—The heating unit, shown in detail in
2 Fig. 1, shall consist of a 500-W Nichrome element helically
1.1 This test method covers a general procedure for deter-
supported by ceramic insulators inside a 2-in. (50.8-mm)
mining the thermal conductivity of whiteware ceramics over
diameter brass cylinder. This brass cylinder shall be highly
the temperature range from 100 to 300°F (40 to 150°C).
polished to serve also as a reflector, since heat transmission to
1.2 The values stated in inch-pound units are to be regarded
the upper thermode is primarily by radiation. Line voltage to
as the standard. The SI (metric) units given in parentheses are
the heater circuit shall be held constant to within 60.1 % by
for information purposes only.
means of an electronic voltage regulator, and power input to
1.3 This standard does not purport to address all of the
the heater shall be controlled by a variable transformer.
safety concerns, if any, associated with its use. It is the 3.1.2 Thermodes—The thermodes to which the ceramic test
responsibility of the user of this standard to establish appro-
specimen is soldered shall be machined from electrolytically
priate safety and health practices and determine the applica- deposited pure copper to tolerances of 60.001 in. (0.03 mm)
bility of regulatory limitations prior to use.
on diameters. Thermodes of diameters from 0.250 to 0.500 in.
(6.50 to 12.70 mm) may be used, but in all cases the diameters
2. Significance and Use
of the specimen, and that portion of the upper and lower
2.1 This test method provides information useful in under- thermodes incorporating the thermocouple shall be equal in
standing and quantifying such parameters as thermal shock diameter to within 60.001 in. (0.03 mm). The section of the
resistance and ability to conduct or dissipate heat. upper thermode above the upper cooling jacket shall be coated
with carbon black to increase its emissivity.
3. Apparatus
3.1.3 Cooling Jackets—Details of the lower cooling jacket
3
3.1 Essentially,theapparatus shallconsistofaheatingunit, are shown in Fig. 1. The lower thermode makes contact with
upper and lower copper “thermodes” (bars that serve to the lower cooling jacket by means of a tapered fit. The upper
1
introduce heat) to which the ceramic test specimen is soldered, ⁄8-in. (3.2-mm) brass plate which supports the heating unit
and a cooling jacket. The foregoing set of parts shall be shall also be water-cooled for the purpose of eliminating
enclosed by a 5-in. (127-mm) diameter brass cylinder, 12 in. radiation from the heating unit to the thermodes and test
(305 mm) long, which is sealed to the base with a rubber specimen below. In addition, the upper thermode shall be fitted
with a copper reflecting shield to prohibit any direct radiation
gasket. With the exception of the copper thermodes and the
coppercoolingjackets,theinstrumentshallbemadeentirelyof from striking the thermodes and specimen in the chamber
below. A water-circulating system shall be provided for sup-
brass with all joints silver soldered. During operation, the
system shall be evacuated to a pressure of approximately 1 µm plying the cooling jackets with water at constant pressure and
temperature. The water temperatures shall not vary at a rate
of mercury with an oil-diffusion pump which is backed up with
a mechanical vacuum pump. greater than 1°F (0.5°C)/h.
3.1.4 Thermocouples—Calibrated glass-asbestos insulated
iron-constantan thermocouples shall be permanently attached
1
This test method is under the jurisdiction ofASTM CommitteeC21 on Ceramic
to the thermodes in positions 1.75 in. (44.4 mm) apart as noted
Whitewares and Related Products and is the direct responsibility of Subcommittee
C21.03 on Methods for Whitewares and Environmental Concerns.
in Fig. 2. The diameter of the thermocouple wires used shall
Current edition approved July 1, 2016. Published July 2016. Originally approved
not exceed the diameter of No. 28 AWG (0.321 mm). The
in 1957. Last previous edition approved in 2011 as C408 – 88 (2011). DOI:
thermocouple wires shall be permanently attached to the
10.1520/C0408-88R16.
2
thermode by silver-soldering each wire of the thermocouple
This work was done under the sponsorship of the U.S. Signal Corps., Squier
Sign
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C408 − 88 (Reapproved 2011) C408 − 88 (Reapproved 2016)
Standard Test Method for
1
Thermal Conductivity of Whiteware Ceramics
This standard is issued under the fixed designation C408; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
2
1.1 This test method covers a general procedure for determining the thermal conductivity of whiteware ceramics over the
temperature range from 100 to 300°F (40 to 150°C).
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI (metric) units given in parentheses are for
information purposes only.
1.3 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 appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Significance and Use
2.1 This test method provides information useful in understanding and quantifying such parameters as thermal shock resistance
and ability to conduct or dissipate heat.
3. Apparatus
3
3.1 Essentially, the apparatus shall consist of a heating unit, upper and lower copper “thermodes” (bars that serve to introduce
heat) to which the ceramic test specimen is soldered, and a cooling jacket. The foregoing set of parts shall be enclosed by a 5-in.
(127-mm) diameter brass cylinder, 12 in. (305 mm) long, which is sealed to the base with a rubber gasket. With the exception of
the copper thermodes and the copper cooling jackets, the instrument shall be made entirely of brass with all joints silver soldered.
During operation, the system shall be evacuated to a pressure of approximately 1 μm of mercury with an oil-diffusion pump which
is backed up with a mechanical vacuum pump.
3.1.1 Heating Unit—The heating unit, shown in detail in Fig. 1, shall consist of a 500-W Nichrome element helically supported
by ceramic insulators inside a 2-in. (50.8-mm) diameter brass cylinder. This brass cylinder shall be highly polished to serve also
as a reflector, since heat transmission to the upper thermode is primarily by radiation. Line voltage to the heater circuit shall be
held constant to within 60.1 % by means of an electronic voltage regulator, and power input to the heater shall be controlled by
a variable transformer.
3.1.2 Thermodes—The thermodes to which the ceramic test specimen is soldered shall be machined from electrolytically
deposited pure copper to tolerances of 60.001 in. (0.03 mm) on diameters. Thermodes of diameters from 0.250 to 0.500 in. (6.50
to 12.70 mm) may be used, but in all cases the diameters of the specimen, and that portion of the upper and lower thermodes
incorporating the thermocouple shall be equal in diameter to within 60.001 in. (0.03 mm). The section of the upper thermode
above the upper cooling jacket shall be coated with carbon black to increase its emissivity.
3.1.3 Cooling Jackets—Details of the lower cooling jacket are shown in Fig. 1. The lower thermode makes contact with the
1
lower cooling jacket by means of a tapered fit. The upper ⁄8-in. (3.2-mm) brass plate which supports the heating unit shall also
be water-cooled for the purpose of eliminating radiation from the heating unit to the thermodes and test specimen below. In
addition, the upper thermode shall be fitted with a copper reflecting shield to prohibit any direct radiation from striking the
1
This test method is under the jurisdiction of ASTM Committee C21 on Ceramic Whitewares and Related Products and is the direct responsibility of Subcommittee C21.03
on Methods for Whitewares and Environmental Concerns.
Current edition approved March 1, 2011July 1, 2016. Published March 2011July 2016. Originally approved in 1957. Last previous edition approved in 20062011 as
C408 – 88 (2011). (2006). DOI: 10.1520/C0408-88R11.10.1520/C0408-88R16.
2
This work was done under the sponsorship of the U.S. Signal Corps., Squier Signal Laboratory, Ft. Monmouth, NJ, and the U.S. Air Force, Wright-Patterson Air
Development Center, OH.
3
A suitable type of apparatus is described by Edwin Ruh in “Improved Method of Measuring Thermal Conductivity of Dense Ceramics,” Journal, Am. Ceramic Society,
Vol 37, 1954, No. 5, pp. 2
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.