ASTM C714-17
(Test Method)Standard Test Method for Thermal Diffusivity of Carbon and Graphite by Thermal Pulse Method
Standard Test Method for Thermal Diffusivity of Carbon and Graphite by Thermal Pulse Method
SIGNIFICANCE AND USE
5.1 Thermal diffusivity is an important property required for such purposes as design applications under transient heat flow conditions, determination of safe operating temperature, process control, and quality assurance.
5.2 The flash method is used to measure values of thermal diffusivity (α) of a wide range of solid materials. It is particularly advantageous because of the simple specimen geometry, small specimen size requirements, rapidity of measurement, and ease of handling materials having a wide range of thermal diffusivity values over a large temperature range with a single apparatus. The short measurement times involved reduce the chances of contamination and change of specimen properties due to exposure to high temperature environments.
5.3 Thermal diffusivity results in many cases can be combined with values for specific heat (Cp) and density (ρ) to derive thermal conductivity (λ) from the relation λ = αCpρ. For guidance on converting thermal diffusivity to thermal conductivity, refer to Practice C781.
5.4 This test method can be used to characterize graphite for design purposes.
5.5 Test Method E1461 is a more detailed form of this test method and has applicability to much wider ranges of materials, applications, and temperatures.
SCOPE
1.1 This test method covers the determination of the thermal diffusivity of carbons and graphite at temperatures up to 500 °C. It requires only a small easily fabricated specimen. Thermal diffusivity values in the range from 0.04 cm2/s to 2.0 cm2/s are readily measurable by this test method; however, for the reason outlined in Section 7, for materials outside this range this test method may require modification.
1.2 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.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C714 − 17
Standard Test Method for
Thermal Diffusivity of Carbon and Graphite by Thermal
1
Pulse Method
This standard is issued under the fixed designation C714; 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* per unit time through a unit area with a temperature gradient of
one degree per unit distance.
1.1 Thistestmethodcoversthedeterminationofthethermal
3.1.2 thermal diffusivity, n—a measure of the ability of a
diffusivity of carbons and graphite at temperatures up to
materialtoconductthermalenergyrelativetoitsabilitytostore
500 °C. It requires only a small easily fabricated specimen.
2
thermal energy; it is equal to the thermal conductivity divided
Thermal diffusivity values in the range from 0.04 cm /s to
2
by density and specific heat capacity at constant pressure.
2.0 cm /s are readily measurable by this test method; however,
for the reason outlined in Section 7, for materials outside this
4. Summary of Test Method
range this test method may require modification.
4.1 A high-intensity short-duration thermal pulse from a
1.2 This standard does not purport to address all of the
flash lamp is absorbed on the front surface of a specimen; and
safety concerns, if any, associated with its use. It is the
the rear surface temperature change as a function of time is
responsibility of the user of this standard to establish appro-
observed on an oscilloscope. The pulse raises the average
priate safety and health practices and determine the applica-
temperature of the specimen only a few degrees above its
bility of regulatory limitations prior to use.
initial value. The ambient temperature of the specimen is
1.3 This international standard was developed in accor-
controlled by a furnace or cryostat. Thermal diffusivity is
dance with internationally recognized principles on standard-
calculated from the specimen thickness and the time required
ization established in the Decision on Principles for the
for the temperature of the back surface to rise to one half of its
Development of International Standards, Guides and Recom-
3
maximum value (1).
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4.2 The critical factors in this test method are:
1
4.2.1 τ/t ⁄2 must be 0.02 or less.τ is the pulse time as defined
2. Referenced Documents
1
in Fig. 1 and t ⁄2 is the time for the rear surface temperature to
2
2.1 ASTM Standards:
rise to one half of its maximum value (see Fig. 2).
C781 PracticeforTestingGraphiteMaterialsforGas-Cooled
4.2.2 Heat losses from the specimen via radiation,
Nuclear Reactor Components
convection, or conduction to the specimen holder must be
D7775 Guide for Measurements on Small Graphite Speci-
small. Whether or not this condition is violated can be
mens
determined experimentally from the oscilloscope trace, an
E1461 Test Method for Thermal Diffusivity by the Flash
1 1
example of which is shown in Fig. 2.If ∆ T(10 t ⁄2 )/∆ T(t ⁄2)>
Method
1.98, the heat losses are assumed to be zero.
4.2.3 The oscilloscope trace must be such that ∆T , ∆
max
3. Terminology
1 1
T(10 t ⁄2 ), and t ⁄2 can be determined to 62%.
3.1 Definitions:
4.2.4 The other conditions are less critical, and the experi-
3.1.1 thermal conductivity, n—the rate at which heat passes
menter is left to his discretion.
through a material, expressed as the amount of heat that flows
5. Significance and Use
1
This test method is under the jurisdiction of ASTM Committee D02 on
5.1 Thermaldiffusivityisanimportantpropertyrequiredfor
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
such purposes as design applications under transient heat flow
Subcommittee D02.F0 on Manufactured Carbon and Graphite Products.
conditions, determination of safe operating temperature, pro-
Current edition approved May 1, 2017. Published May 2017. Originally
approved in 1972. Last previous edition approved in 2015 as C714 – 05 (2015).
cess control, and quality assurance.
DOI: 10.1520/C0714-17.
2
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
3
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to the list of references at the end of
the ASTM website. this test method.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM
...
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: C714 − 05 (Reapproved 2015) C714 − 17 An American National Standard
Standard Test Method for
Thermal Diffusivity of Carbon and Graphite by Thermal
1
Pulse Method
This standard is issued under the fixed designation C714; 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 Scope*
1.1 This test method covers the determination of the thermal diffusivity of carbons and graphite to 65 % at temperatures up to
2 2
500 °C. It requires only a small easily fabricated specimen. Thermal diffusivity values in the range from 0.04 cm /s to 2.0 cm /s
are readily measurable by this test method; however, for the reason outlined in Section 57, for materials outside this range this test
method may require modification.
1.2 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.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
C781 Practice for Testing Graphite and Boronated Graphite Materials for High-Temperature Gas-Cooled Nuclear Reactor
Components
D7775 Guide for Measurements on Small Graphite Specimens
E1461 Test Method for Thermal Diffusivity by the Flash Method
3. Terminology
3.1 Definitions:
3.1.1 thermal conductivity, n—the rate at which heat passes through a material, expressed as the amount of heat that flows per
unit time through a unit area with a temperature gradient of one degree per unit distance.
3.1.2 thermal diffusivity, n—a measure of the ability of a material to conduct thermal energy relative to its ability to store thermal
energy; it is equal to the thermal conductivity divided by density and specific heat capacity at constant pressure.
4. Summary of Test Method
4.1 A high-intensity short-duration thermal pulse from a flash lamp is absorbed on the front surface of a specimen; and the rear
surface temperature change as a function of time is observed on an oscilloscope. The pulse raises the average temperature of the
specimen only a few degrees above its initial value. The ambient temperature of the specimen is controlled by a furnace or cryostat.
Thermal diffusivity is calculated from the specimen thickness and the time required for the temperature of the back surface to rise
3
to one half of its maximum value (1).
4.2 The critical factors in this test method are:
1 1
4.2.1 τ/t ⁄2 must be 0.02 or less. τ is the pulse time as defined in Fig. 1 and t ⁄2 is the time for the rear surface temperature to rise
to one half of its maximum value (see Fig. 2).
1
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.F0 on Manufactured Carbon and Graphite Products.
Current edition approved Oct. 1, 2015May 1, 2017. Published December 2015May 2017. Originally approved in 1972. Last previous edition approved in 20102015 as
C714 – 05 (2010).(2015). DOI: 10.1520/C0714-05R15.10.1520/C0714-17.
2
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.
3
The boldface numbers in parentheses refer to the list of references at the end of this test method.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
C714 − 17
FIG. 1 Flash Tube Response
FIG. 2 Example of Oscilloscope Trace Showing Parameters Used to Calculate Thermal Diffusivity
4.2.2 Heat losses from the specimen via radiation, convection, or conduction to the specimen holder must be small. Whether
or not this condition is violated can be determined experimenta
...
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: C714 − 17
Standard Test Method for
Thermal Diffusivity of Carbon and Graphite by Thermal
1
Pulse Method
This standard is issued under the fixed designation C714; 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* per unit time through a unit area with a temperature gradient of
one degree per unit distance.
1.1 This test method covers the determination of the thermal
3.1.2 thermal diffusivity, n—a measure of the ability of a
diffusivity of carbons and graphite at temperatures up to
material to conduct thermal energy relative to its ability to store
500 °C. It requires only a small easily fabricated specimen.
2
thermal energy; it is equal to the thermal conductivity divided
Thermal diffusivity values in the range from 0.04 cm /s to
2
by density and specific heat capacity at constant pressure.
2.0 cm /s are readily measurable by this test method; however,
for the reason outlined in Section 7, for materials outside this
4. Summary of Test Method
range this test method may require modification.
4.1 A high-intensity short-duration thermal pulse from a
1.2 This standard does not purport to address all of the
flash lamp is absorbed on the front surface of a specimen; and
safety concerns, if any, associated with its use. It is the
the rear surface temperature change as a function of time is
responsibility of the user of this standard to establish appro-
observed on an oscilloscope. The pulse raises the average
priate safety and health practices and determine the applica-
temperature of the specimen only a few degrees above its
bility of regulatory limitations prior to use.
initial value. The ambient temperature of the specimen is
1.3 This international standard was developed in accor-
controlled by a furnace or cryostat. Thermal diffusivity is
dance with internationally recognized principles on standard-
calculated from the specimen thickness and the time required
ization established in the Decision on Principles for the
for the temperature of the back surface to rise to one half of its
Development of International Standards, Guides and Recom-
3
maximum value (1).
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4.2 The critical factors in this test method are:
1
4.2.1 τ/t ⁄2 must be 0.02 or less. τ is the pulse time as defined
2. Referenced Documents
1
in Fig. 1 and t ⁄2 is the time for the rear surface temperature to
2
2.1 ASTM Standards:
rise to one half of its maximum value (see Fig. 2).
C781 Practice for Testing Graphite Materials for Gas-Cooled
4.2.2 Heat losses from the specimen via radiation,
Nuclear Reactor Components
convection, or conduction to the specimen holder must be
D7775 Guide for Measurements on Small Graphite Speci-
small. Whether or not this condition is violated can be
mens
determined experimentally from the oscilloscope trace, an
E1461 Test Method for Thermal Diffusivity by the Flash
1 1
example of which is shown in Fig. 2. If Δ T(10 t ⁄2 )/Δ T(t ⁄2 ) >
Method
1.98, the heat losses are assumed to be zero.
4.2.3 The oscilloscope trace must be such that ΔT , Δ
max
3. Terminology
1 1
T(10 t ⁄2 ), and t ⁄2 can be determined to 62 %.
3.1 Definitions:
4.2.4 The other conditions are less critical, and the experi-
3.1.1 thermal conductivity, n—the rate at which heat passes
menter is left to his discretion.
through a material, expressed as the amount of heat that flows
5. Significance and Use
1
This test method is under the jurisdiction of ASTM Committee D02 on
5.1 Thermal diffusivity is an important property required for
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
such purposes as design applications under transient heat flow
Subcommittee D02.F0 on Manufactured Carbon and Graphite Products.
conditions, determination of safe operating temperature, pro-
Current edition approved May 1, 2017. Published May 2017. Originally
approved in 1972. Last previous edition approved in 2015 as C714 – 05 (2015).
cess control, and quality assurance.
DOI: 10.1520/C0714-17.
2
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
3
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to the list of references at the end of
the ASTM website. this test method.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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...
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