ASTM D6744-06(2017)e1
(Test Method)Standard Test Method for Determination of the Thermal Conductivity of Anode Carbons by the Guarded Heat Flow Meter Technique
Standard Test Method for Determination of the Thermal Conductivity of Anode Carbons by the Guarded Heat Flow Meter Technique
SIGNIFICANCE AND USE
5.1 This test method is designed to measure and compare thermal properties of materials under controlled conditions and their ability to maintain required thermal conductance levels.
SCOPE
1.1 This test method covers a steady-state technique for the determination of the thermal conductivity of carbon materials in thicknesses of less than 25 mm. The test method is useful for homogeneous materials having a thermal conductivity in the approximate range 1−4 m2 ·K/W) over the approximate temperature range from 150 K to 600 K. It can be used outside these ranges with reduced accuracy for thicker specimens and for thermal conductivity values up to 60 W/(m·K).
Note 1: It is not recommended to test graphite cathode materials using this test method. Graphites usually have a very low thermal resistance, and the interfaces between the specimen to be tested and the instrument become more significant than the specimen itself.
1.2 This test method is similar in concept to Test Methods E1530 and C518. Significant attention has been paid to ensure that the thermal resistance of contacting surfaces is minimized and reproducible.
1.3 The values stated in SI units are regarded as standard.
1.3.1 Exception—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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Buy Standard
Standards Content (Sample)
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.
´1
Designation: D6744 − 06 (Reapproved 2017)
Standard Test Method for
Determination of the Thermal Conductivity of Anode
Carbons by the Guarded Heat Flow Meter Technique
This standard is issued under the fixed designation D6744; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Units formatting was corrected editorially in February 2017.
1. Scope Properties by Means of the Heat Flow Meter Apparatus
E1530Test Method for Evaluating the Resistance to Ther-
1.1 This test method covers a steady-state technique for the
mal Transmission of Materials by the Guarded Heat Flow
determination of the thermal conductivity of carbon materials
Meter Technique
inthicknessesoflessthan25mm.Thetestmethodisusefulfor
homogeneous materials having a thermal conductivity in the
3. Terminology
approximate range 1< λ < 30 W/(m·K), (thermal resistance in
−4 2
the range from 10 to 400 × 10 m ·K/W) over the approxi- 3.1 Definitions of Terms Specific to This Standard:
mate temperature range from 150K to 600K. It can be used
3.1.1 average temperature, n—the average temperature of a
outside these ranges with reduced accuracy for thicker speci-
surface is the area-weighted mean temperature of that surface.
mens and for thermal conductivity values up to 60W⁄(m·K).
3.1.2 heat flux transducer, HFT, n—a device that produces
an electrical output that is a function of the heat flux, in a
NOTE1—Itisnotrecommendedtotestgraphitecathodematerialsusing
thistestmethod.Graphitesusuallyhaveaverylowthermalresistance,and
predefined and reproducible manner.
the interfaces between the specimen to be tested and the instrument
3.1.3 thermal conductance, C, n—the time rate of heat flux
become more significant than the specimen itself.
through a unit area of a body induced by unit temperature
1.2 This test method is similar in concept to Test Methods
difference between the body surfaces.
E1530 and C518. Significant attention has been paid to ensure
3.1.4 thermal conductivity, λ, of a solid material, n—the
that the thermal resistance of contacting surfaces is minimized
time rate of heat flow, under steady conditions, through unit
and reproducible.
area, per unit temperature gradient in the direction perpendicu-
1.3 The values stated in SI units are regarded as standard.
lar to the area.
1.3.1 Exception—The values given in parentheses are for
3.1.5 thermal resistance, R, n—the reciprocal of thermal
information only.
conductance.
1.4 This standard does not purport to address all of the
3.2 Symbols:
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
λ = thermal conductivity, W/(m·K), [Btu·in/(h·ft ·°F)]
priate safety and health practices and determine the applica-
2 2
C = thermal conductance, W/(m ·K), [Btu/(h·ft ·°F)]
bility of regulatory limitations prior to use. 2 2
R = thermal resistance, m ·K/W, (h·ft ·°F/Btu)
∆x = specimen thickness, mm, (in.)
2. Referenced Documents
2 2
A = specimen cross sectional area, m , (ft )
2.1 ASTM Standards: Q = heat flow, W, (Btu/h)
φ = heat flux transducer output, mV
C518Test Method for Steady-State Thermal Transmission
N = heat flux transducer calibration constant, W/(m ·mV),
[Btu/(h·ft ·mV)]
2 2
This test method is under the jurisdiction of ASTM Committee D02 on Nφ = heat flux, W/m , [Btu/(h·ft )]
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
∆T = temperature difference,° C, (°F)
SubcommitteeD02.05onPropertiesofFuels,PetroleumCokeandCarbonMaterial.
T = temperature of guard heater, °C, (°F)
g
Current edition approved Jan. 1, 2017. Published February 2017. Originally
T = temperature of upper heater, °C, (°F)
ɛ1
u
approved in 2001. Last previous edition in 2011 as D6744–06 (2011) . DOI:
T = temperature of lower heater, °C, (°F)
10.1520/D6744-06R17E01. l
For referenced ASTM standards, visit the ASTM website, www.astm.org, or T = temperature of one surface of the specimen, °C, (°F)
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
T = temperature of the other surface of the specimen, °C,
Standards volume information, refer to the standard’s Document Summary page on
(°F)
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D6744 − 06 (2017)
6. Apparatus
T = mean temperature of the specimen, °C, (°F)
m
s = unknown specimen
6.1 Aschematicrenderingofatypicalapparatusisshownin
r = known calibration or reference specimen
Fig. 1. The relative position of the HFT to sample is not
o = contacts
important(itmaybeonthehotorcoldside)asthetestmethod
is based on maintaining axial heat flow with minimal heat
4. Summary of Test Method
losses or gains radially. It is also up to the designer whether to
choose heat flow upward or downward or horizontally, al-
4.1 A specimen and a heat flux transducer (HFT) are
sandwiched between two flat plates controlled at different though downward heat flow in a vertical stack is the most
common one.
temperatures, to produce a heat flow through the test stack. A
reproducible load is applied to the test stack by pneumatic or
6.2 Key Components of a Typical Device:
hydraulic means, to ensure that there is a reproducible contact
6.2.1 The compressive force for the stack is to be provided
resistance between the specimen and plate surfaces. A cylin-
by either a regulated pneumatic or hydraulic cylinder (1) or a
drical guard surrounds the test stack and is maintained at a
spring loaded mechanism. In either case, means must be
uniform mean temperature of the two plates, in order to
provided to ensure that the loading can be varied and set to
minimize lateral heat flow to and from the stack. At steady-
certain values reproducibility.
state, the difference in temperature between the surfaces
6.2.2 The loading force must be transmitted to the stack
contacting the specimen is measured with temperature sensors
through a gimball joint (2) that allows up to 5° swivel in the
embeddedinthesurfaces,togetherwiththeelectricaloutputof
plane perpendicular to the axis of the stack.
the HFT. This output (voltage) is proportional to the heat flow
6.2.3 Suitable insulator plate (3) separates the gimball joint
through the specimen, the HFT and the interfaces between the
from the top plate (4).
specimen and the apparatus. The proportionality is obtained
6.2.4 The top plate (assumed to be the hot plate for the
through prior calibration of the system with specimens of
purposes of this description) is equipped with a heater (5) and
knownthermalresistancemeasuredunderthesameconditions,
control thermocouple (6) adjacent to the heater, to maintain a
suchthatcontactresistanceatthesurfaceismadereproducible.
certain desired temperature. (Other means of producing and
maintaining temperature may also be used as long as the
5. Significance and Use
requirements under 6.3 are met.) The construction of the top
5.1 This test method is designed to measure and compare plate is such as to ensure uniform heat distribution across its
thermalpropertiesofmaterialsundercontrolledconditionsand face contacting the sample (8). Attached to this face (or
their ability to maintain required thermal conductance levels. embedded in close proximity to it), in a fashion that does not
FIG. 1 Key Components of a Typical Device
´1
D6744 − 06 (2017)
interfere with the sample/plate interface, is a temperature (60.001in.), such that a uniform thickness within 0.025mm
sensor (7) (typically a thermocouple, thermistor) that defines (60.001in.)isattainedintherangefrom12.7mmto25.4mm
the temperature of the interface on the plate side. (0.5in. to 1.0in.)
6.2.5 The sample (8) is in direct contact with the top plate
on one side and an intermediate plate (9) on the other side. 8. Sampling and Conditioning
6.2.6 The intermediate plate (9) is an optional item. Its
8.1 Cut representative test specimens from larger pieces of
purpose is to provide a highly conductive environment to the
the sample material or body.
second temperature sensor (10), to obtain an average tempera-
8.2 Condition the cut specimens in accordance with the
ture of the surface. If the temperature sensor (10) is embedded
requirements of the appropriate material specifications, if any.
into the face of the HFT, or other means are provided to define
the temperature of the surface facing the sample, the use of the
9. Calibration
intermediate plate is not mandatory.
6.2.7 Heat flux transducer (HFT) is a device that will 9.1 Select the mean temperature and load conditions re-
quired. Adjust the upper heater temperature (T ) and lower
generate an electrical signal in proportion to the heat flux
u
across it. The level of output required (sensitivity) greatly heater temperature (T) such that the temperature difference at
l
the required mean temperature is no less than 30°C to 35°C
depends on the rest of the instrumentation used to read it. The
overallperformanceoftheHFTanditsreadoutinstrumentation and the specimen ∆T is not less than 3°C. Adjust the guard
heater temperature (T ) such that it is at approximately the
shall be such as to meet the requirements in Section 13.
g
6.2.8 The lower plate (12) is constructed similarly to the average of T and T.
u l
upper plate (4), except it is positioned as a mirror image.
9.2 Selectatleasttwocalibrationspecimenshavingthermal
6.2.9 An insulator plate (16) separates the lower plate (12)
resistance values that bracket the range expected for the test
from the heat sink (17). In case of using circulating fluid in
specimens at the temperature conditions required.
placeofaheater/thermocouplearrangementintheupperand/or
9.3 Table 1 contains a list of several available materials
lower plates, the heat sink may or may not be present.
commonly used for calibration, together with corresponding
6.2.10 The entire stack is surrounded by a cylindrical guard
thermal resistance (R ) values for a given thickness. This
s
(18) equipped with a heater (19) and a control thermocouple
information is provided to assist the user in selecting optimum
(20) to maintain it at the mean temperature between the upper
specimenthicknessfortestingamaterialandindecidingwhich
and lower plates.Asmall, generally unfilled gap separates the
calibration specimens to use.
guard from the stack. For instruments limited to operate in the
9.4 The range of thermal conductivity for which this test
ambient region, no guard is required. A draft shield is recom-
mended in place of it. method is most suitable is such that the optimum thermal
−4 −4 −2
resistancerangeisfrom10×10 to400×10 m ·K/W.The
NOTE 2—It is permissible to use thin layers of high conductivity grease
most commonly used calibration materials are the Pyrex 7740,
or elastomeric material on the two surfaces of the specimen to reduce the
Pyroceram 9606, and stainless steel.
thermal resistance of the interface and promote uniform thermal contact
across the interface area.
9.5 Measure the thickness of the specimen to 25µm.
NOTE 3—The cross sectional area of the specimen may be any,
however,mostcommonlycircularandrectangularcrosssectionsareused.
9.6 Coatbothsurfacesofacalibrationspecimenwithavery
Minimum size is dictated by the magnitude of the disturbance caused by
thin layer of a compatible heat sink compound or place a thin
thermal sensors in relation to the overall flux distribution. The most
layer of elastomeric heat transfer medium on it to help
common sizes are 25mm round or square to 50mm round.
minimize the thermal resistance at the interfaces of adjacent
6.3 Requirements:
contacting surfaces.
6.3.1 Temperature control of upper and lower plate is to be
60.1°C (6 0.18°F) or better.
6.3.2 Reproducible load of 0.28MPa (40psi) has been
found to be satisfactory for solid specimens. Minimum load TABLE 1 Typical Thermal Resistance Values of Specimens of
Different Materials
shall not be below 0.07MPa (10psi).
6.3.3 Temperature sensors are usually fine gauge or small Material Approximate Thickness, Approximate
Thermal mm Thermal
diameter sheath thermocouples, however, ultraminiature resis-
Conductivity, Resistance,
−4
tance thermometers and linear thermistors may also be used.
W/(m·K) at 10 m ·K/W at
30 °C 30 °C
6.3.4 Operating range of a device using a mean temperature
A
Pyroceram 9606 420 50
guard shall be limited to −100°C to 300°C, when using
A
Pyroceram 9606 410 25
thermocouples as temperature sensors, and −180°C to 300°C
A
Pyrex 7740 Glass 1 20 200
A
with platinum resistance thermometers.
Pyrex 7740 Glass 1 10 100
A
Pyrex 7740 Glass 1 1 10
304 Stainless Steel 14 20 14
7. Test Specimen
304 Stainless Steel 14 10 7
B
Vespel 0.4 2 50
7.1 Thespecimentobetestedshallberepresentativeforthe
A
Pyrex 7740 and Pyroceram 9606 are products and trademarks of Corning Glass
sample material. The recommended specimen configuration is
Co., Corning, WV.
a 50.8mm 6 0.25mm (2in. 6 0.010in.) diameter disk, B
Vespel is a product of DuPont Co.
having smooth flat and parallel faces, 60.025 mm
´1
D6744 − 06 (2017)
9.7 Insert the calibration specimen into the test chamber. 1
C 5 (2)
s
Exercise care to ensure that all surfaces are free of any foreign R
s
matter.
11.1.1 For homogeneous materials:
9.8 Close the test chamber and clamp the calibration speci-
∆x
men in position between the plates at the recommended
R 5 (3)
s
λ
compressive load of 0.28MPa.
11.1.2 In Eq 1, N and R are temperature-and load-
9.9 Wait for thermal equilibrium to be attained.This should
dependentparametersobtainedbycalibrationateachparticular
be seen when all the temperatures measured do not drift more
set of conditions. Once obtained, they should remain fixed for
than 0.1°C in 1min. Read and record all temperatures and the
the particular settings used to attain the conditions.
output of the heat flux transducer.
NOTE 4—The time to attain thermal equilibrium is dependent upon the
NOTE 8—Since N is also determined by the particular HFTutilized, the
thickness of the specimen and its thermal properties. Experience shows
calibration should be checked occasionally to ensure that continuous
that approximately 1h is needed for thermal equilibrium to be attained,
heating/cycling does not affect the HFT.
when testing a specimen with the thermal conductivity within the
NOTE 9—The parameter R depends on the para
...
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
´1
Designation: D6744 − 06 (Reapproved 2017)
Standard Test Method for
Determination of the Thermal Conductivity of Anode
Carbons by the Guarded Heat Flow Meter Technique
This standard is issued under the fixed designation D6744; 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.
ε NOTE—Units formatting was corrected editorially in February 2017.
1. Scope Properties by Means of the Heat Flow Meter Apparatus
E1530 Test Method for Evaluating the Resistance to Ther-
1.1 This test method covers a steady-state technique for the
mal Transmission of Materials by the Guarded Heat Flow
determination of the thermal conductivity of carbon materials
Meter Technique
in thicknesses of less than 25 mm. The test method is useful for
homogeneous materials having a thermal conductivity in the
3. Terminology
approximate range 1< λ < 30 W/(m·K), (thermal resistance in
−4 2
the range from 10 to 400 × 10 m ·K/W) over the approxi-
3.1 Definitions of Terms Specific to This Standard:
mate temperature range from 150 K to 600 K. It can be used
3.1.1 average temperature, n—the average temperature of a
outside these ranges with reduced accuracy for thicker speci-
surface is the area-weighted mean temperature of that surface.
mens and for thermal conductivity values up to 60 W ⁄(m·K).
3.1.2 heat flux transducer, HFT, n—a device that produces
an electrical output that is a function of the heat flux, in a
NOTE 1—It is not recommended to test graphite cathode materials using
this test method. Graphites usually have a very low thermal resistance, and
predefined and reproducible manner.
the interfaces between the specimen to be tested and the instrument
3.1.3 thermal conductance, C, n—the time rate of heat flux
become more significant than the specimen itself.
through a unit area of a body induced by unit temperature
1.2 This test method is similar in concept to Test Methods
difference between the body surfaces.
E1530 and C518. Significant attention has been paid to ensure
3.1.4 thermal conductivity, λ, of a solid material, n—the
that the thermal resistance of contacting surfaces is minimized
time rate of heat flow, under steady conditions, through unit
and reproducible.
area, per unit temperature gradient in the direction perpendicu-
1.3 The values stated in SI units are regarded as standard.
lar to the area.
1.3.1 Exception—The values given in parentheses are for
3.1.5 thermal resistance, R, n—the reciprocal of thermal
information only.
conductance.
1.4 This standard does not purport to address all of the
3.2 Symbols:
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
λ = thermal conductivity, W/(m·K), [Btu·in/(h·ft ·°F)]
priate safety and health practices and determine the applica-
2 2
C = thermal conductance, W/(m ·K), [Btu/(h·ft ·°F)]
bility of regulatory limitations prior to use.
2 2
R = thermal resistance, m ·K/W, (h·ft ·°F/Btu)
Δx = specimen thickness, mm, (in.)
2. Referenced Documents 2 2
A = specimen cross sectional area, m , (ft )
2.1 ASTM Standards: Q = heat flow, W, (Btu/h)
C518 Test Method for Steady-State Thermal Transmission φ = heat flux transducer output, mV
N = heat flux transducer calibration constant, W/(m ·mV),
[Btu/(h·ft ·mV)]
2 2
This test method is under the jurisdiction of ASTM Committee D02 on Nφ = heat flux, W/m , [Btu/(h·ft )]
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
ΔT = temperature difference,° C, (°F)
Subcommittee D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
T = temperature of guard heater, °C, (°F)
g
Current edition approved Jan. 1, 2017. Published February 2017. Originally
T = temperature of upper heater, °C, (°F)
ɛ1
u
approved in 2001. Last previous edition in 2011 as D6744 – 06 (2011) . DOI:
T = temperature of lower heater, °C, (°F)
10.1520/D6744-06R17E01. l
T = temperature of one surface of the specimen, °C, (°F)
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
T = temperature of the other surface of the specimen, °C,
Standards volume information, refer to the standard’s Document Summary page on
(°F)
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D6744 − 06 (2017)
6. Apparatus
T = mean temperature of the specimen, °C, (°F)
m
s = unknown specimen
6.1 A schematic rendering of a typical apparatus is shown in
r = known calibration or reference specimen
Fig. 1. The relative position of the HFT to sample is not
o = contacts
important (it may be on the hot or cold side) as the test method
is based on maintaining axial heat flow with minimal heat
4. Summary of Test Method
losses or gains radially. It is also up to the designer whether to
4.1 A specimen and a heat flux transducer (HFT) are choose heat flow upward or downward or horizontally, al-
though downward heat flow in a vertical stack is the most
sandwiched between two flat plates controlled at different
temperatures, to produce a heat flow through the test stack. A common one.
reproducible load is applied to the test stack by pneumatic or
6.2 Key Components of a Typical Device:
hydraulic means, to ensure that there is a reproducible contact
6.2.1 The compressive force for the stack is to be provided
resistance between the specimen and plate surfaces. A cylin-
by either a regulated pneumatic or hydraulic cylinder (1) or a
drical guard surrounds the test stack and is maintained at a
spring loaded mechanism. In either case, means must be
uniform mean temperature of the two plates, in order to
provided to ensure that the loading can be varied and set to
minimize lateral heat flow to and from the stack. At steady-
certain values reproducibility.
state, the difference in temperature between the surfaces
6.2.2 The loading force must be transmitted to the stack
contacting the specimen is measured with temperature sensors
through a gimball joint (2) that allows up to 5° swivel in the
embedded in the surfaces, together with the electrical output of
plane perpendicular to the axis of the stack.
the HFT. This output (voltage) is proportional to the heat flow
6.2.3 Suitable insulator plate (3) separates the gimball joint
through the specimen, the HFT and the interfaces between the
from the top plate (4).
specimen and the apparatus. The proportionality is obtained
6.2.4 The top plate (assumed to be the hot plate for the
through prior calibration of the system with specimens of
purposes of this description) is equipped with a heater (5) and
known thermal resistance measured under the same conditions,
control thermocouple (6) adjacent to the heater, to maintain a
such that contact resistance at the surface is made reproducible.
certain desired temperature. (Other means of producing and
maintaining temperature may also be used as long as the
5. Significance and Use
requirements under 6.3 are met.) The construction of the top
5.1 This test method is designed to measure and compare plate is such as to ensure uniform heat distribution across its
thermal properties of materials under controlled conditions and face contacting the sample (8). Attached to this face (or
their ability to maintain required thermal conductance levels. embedded in close proximity to it), in a fashion that does not
FIG. 1 Key Components of a Typical Device
´1
D6744 − 06 (2017)
interfere with the sample/plate interface, is a temperature (60.001 in.), such that a uniform thickness within 0.025 mm
sensor (7) (typically a thermocouple, thermistor) that defines (6 0.001 in.) is attained in the range from 12.7 mm to 25.4 mm
the temperature of the interface on the plate side. (0.5 in. to 1.0 in.)
6.2.5 The sample (8) is in direct contact with the top plate
8. Sampling and Conditioning
on one side and an intermediate plate (9) on the other side.
6.2.6 The intermediate plate (9) is an optional item. Its
8.1 Cut representative test specimens from larger pieces of
purpose is to provide a highly conductive environment to the
the sample material or body.
second temperature sensor (10), to obtain an average tempera-
8.2 Condition the cut specimens in accordance with the
ture of the surface. If the temperature sensor (10) is embedded
requirements of the appropriate material specifications, if any.
into the face of the HFT, or other means are provided to define
the temperature of the surface facing the sample, the use of the
9. Calibration
intermediate plate is not mandatory.
9.1 Select the mean temperature and load conditions re-
6.2.7 Heat flux transducer (HFT) is a device that will
generate an electrical signal in proportion to the heat flux quired. Adjust the upper heater temperature (T ) and lower
u
heater temperature (T ) such that the temperature difference at
across it. The level of output required (sensitivity) greatly
l
depends on the rest of the instrumentation used to read it. The the required mean temperature is no less than 30 °C to 35 °C
and the specimen ΔT is not less than 3 °C. Adjust the guard
overall performance of the HFT and its readout instrumentation
shall be such as to meet the requirements in Section 13. heater temperature (T ) such that it is at approximately the
g
average of T and T .
6.2.8 The lower plate (12) is constructed similarly to the
u l
upper plate (4), except it is positioned as a mirror image.
9.2 Select at least two calibration specimens having thermal
6.2.9 An insulator plate (16) separates the lower plate (12)
resistance values that bracket the range expected for the test
from the heat sink (17). In case of using circulating fluid in
specimens at the temperature conditions required.
place of a heater/thermocouple arrangement in the upper and/or
9.3 Table 1 contains a list of several available materials
lower plates, the heat sink may or may not be present.
commonly used for calibration, together with corresponding
6.2.10 The entire stack is surrounded by a cylindrical guard
thermal resistance (R ) values for a given thickness. This
s
(18) equipped with a heater (19) and a control thermocouple
information is provided to assist the user in selecting optimum
(20) to maintain it at the mean temperature between the upper
specimen thickness for testing a material and in deciding which
and lower plates. A small, generally unfilled gap separates the
calibration specimens to use.
guard from the stack. For instruments limited to operate in the
ambient region, no guard is required. A draft shield is recom- 9.4 The range of thermal conductivity for which this test
method is most suitable is such that the optimum thermal
mended in place of it.
−4 −4 −2
resistance range is from 10 × 10 to 400 × 10 m ·K/W. The
NOTE 2—It is permissible to use thin layers of high conductivity grease
most commonly used calibration materials are the Pyrex 7740,
or elastomeric material on the two surfaces of the specimen to reduce the
Pyroceram 9606, and stainless steel.
thermal resistance of the interface and promote uniform thermal contact
across the interface area.
9.5 Measure the thickness of the specimen to 25 µm.
NOTE 3—The cross sectional area of the specimen may be any,
however, most commonly circular and rectangular cross sections are used.
9.6 Coat both surfaces of a calibration specimen with a very
Minimum size is dictated by the magnitude of the disturbance caused by
thin layer of a compatible heat sink compound or place a thin
thermal sensors in relation to the overall flux distribution. The most
layer of elastomeric heat transfer medium on it to help
common sizes are 25 mm round or square to 50 mm round.
minimize the thermal resistance at the interfaces of adjacent
6.3 Requirements:
contacting surfaces.
6.3.1 Temperature control of upper and lower plate is to be
60.1 °C (6 0.18 °F) or better.
6.3.2 Reproducible load of 0.28 MPa (40 psi) has been
found to be satisfactory for solid specimens. Minimum load TABLE 1 Typical Thermal Resistance Values of Specimens of
Different Materials
shall not be below 0.07 MPa (10 psi).
Material Approximate Thickness, Approximate
6.3.3 Temperature sensors are usually fine gauge or small
Thermal mm Thermal
diameter sheath thermocouples, however, ultraminiature resis-
Conductivity, Resistance,
−4
tance thermometers and linear thermistors may also be used.
W/(m·K) at 10 m ·K/W at
30 °C 30 °C
6.3.4 Operating range of a device using a mean temperature
A
Pyroceram 9606 4 20 50
guard shall be limited to −100 °C to 300 °C, when using
A
Pyroceram 9606 4 10 25
thermocouples as temperature sensors, and −180 °C to 300 °C
A
Pyrex 7740 Glass 1 20 200
A
with platinum resistance thermometers.
Pyrex 7740 Glass 1 10 100
A
Pyrex 7740 Glass 1 1 10
304 Stainless Steel 14 20 14
7. Test Specimen
304 Stainless Steel 14 10 7
B
Vespel 0.4 2 50
7.1 The specimen to be tested shall be representative for the
A
Pyrex 7740 and Pyroceram 9606 are products and trademarks of Corning Glass
sample material. The recommended specimen configuration is
Co., Corning, WV.
a 50.8 mm 6 0.25 mm (2 in. 6 0.010 in.) diameter disk, B
Vespel is a product of DuPont Co.
having smooth flat and parallel faces, 60.025 mm
´1
D6744 − 06 (2017)
9.7 Insert the calibration specimen into the test chamber. 1
C 5 (2)
s
Exercise care to ensure that all surfaces are free of any foreign R
s
matter.
11.1.1 For homogeneous materials:
9.8 Close the test chamber and clamp the calibration speci-
Δx
men in position between the plates at the recommended
R 5 (3)
s
λ
compressive load of 0.28 MPa.
11.1.2 In Eq 1, N and R are temperature-and load-
9.9 Wait for thermal equilibrium to be attained. This should
dependent parameters obtained by calibration at each particular
be seen when all the temperatures measured do not drift more
set of conditions. Once obtained, they should remain fixed for
than 0.1 °C in 1 min. Read and record all temperatures and the
output of the heat flux transducer. the particular settings used to attain the conditions.
NOTE 4—The time to attain thermal equilibrium is dependent upon the
NOTE 8—Since N is also determined by the particular HFT utilized, the
thickness of the specimen and its thermal properties. Experience shows
calibration should be checked occasionally to ensure that continuous
that approximately 1 h is needed for thermal equilibrium to be attained,
heating/cycling does not affect th
...
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.
´1 ´1
Designation: D6744 − 06 (Reapproved 2011) D6744 − 06 (Reapproved 2017)
Standard Test Method for
Determination of the Thermal Conductivity of Anode
Carbons by the Guarded Heat Flow Meter Technique
This standard is issued under the fixed designation D6744; 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.
ε NOTE—Update wording in Notes 1–4, Units formatting was corrected 6.3.2, 12.1.8, and updated notation in Section
13editorially in August 2011.February 2017.
1. Scope
1.1 This test method covers a steady-state technique for the determination of the thermal conductivity of carbon materials in
thicknesses of less than 25 mm. 25 mm. The test method is useful for homogeneous materials having a thermal conductivity in
−4 2
the approximate range 1< λ < 30 W/(m·K), (thermal resistance in the range from 10 to 400 × 10 m ·K/W) over the approximate
temperature range from 150150 K to 600 K. 600 K. It can be used outside these ranges with reduced accuracy for thicker
specimens and for thermal conductivity values up to 60 60 W W/(m·K).⁄(m·K).
NOTE 1—It is not recommended to test graphite cathode materials using this test method. Graphites usually have a very low thermal resistance, and
the interfaces between the specimen to be tested and the instrument become more significant than the specimen itself.
1.2 This test method is similar in concept to Test Methods E1530 and C518. Significant attention has been paid to ensure that
the thermal resistance of contacting surfaces is minimized and reproducible.
1.3 The values stated in SI units are regarded as standard. The values given in parentheses are for information only.
1.3.1 Exception—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 appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
C518 Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
E1530 Test Method for Evaluating the Resistance to Thermal Transmission of Materials by the Guarded Heat Flow Meter
Technique
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 average temperature, n—the average temperature of a surface is the area-weighted mean temperature of that surface.
3.1.2 heat flux transducer, HFT, n—a device that produces an electrical output that is a function of the heat flux, in a predefined
and reproducible manner.
3.1.3 thermal conductance, C, n—the time rate of heat flux through a unit area of a body induced by unit temperature difference
between the body surfaces.
3.1.4 thermal conductivity, λ, of a solid material, n—the time rate of heat flow, under steady conditions, through unit area, per
unit temperature gradient in the direction perpendicular to the area.
3.1.5 thermal resistance, R, n—the reciprocal of thermal conductance.
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
D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
Current edition approved May 1, 2011Jan. 1, 2017. Published August 2011February 2017. Originally approved in 2001. Last previous edition in 20062011 as
ɛ1
D6744D6744 – 06 (2011) –06. DOI: 10.1520/D6744-06R11.10.1520/D6744-06R17E01.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D6744 − 06 (2017)
3.2 Symbols:
λ = thermal conductivity, W/(m·K), Btu·in/(h·ft ·°F)
λ = thermal conductivity, W/(m·K), [Btu·in/(h·ft ·°F)]
2 2
C = thermal conductance, W/(m ·K), Btu/(h·ft ·°F)
2 2
C = thermal conductance, W/(m ·K), [Btu/(h·ft ·°F)]
2 2
R = thermal resistance, m ·K/W, h·ft ·°F/Btu
2 2
R = thermal resistance, m ·K/W, (h·ft ·°F/Btu)
Δx = specimen thickness, mm, in
Δx = specimen thickness, mm, (in.)
2 2
A = specimen cross sectional area, m , ft
2 2
A = specimen cross sectional area, m , (ft )
Q = heat flow, W, Btu/h
Q = heat flow, W, (Btu/h)
φ = heat flux transducer output, mV
2 2
N = heat flux transducer calibration constant, W/(m ·mV), Btu/(h·ft ·mV)
2 2
N = heat flux transducer calibration constant, W/(m ·mV), [Btu/(h·ft ·mV)]
2 2
Nφ = heat flux, W/m , Btu/(h·ft )
2 2
Nφ = heat flux, W/m , [Btu/(h·ft )]
ΔT = temperature difference,° C, °F
ΔT = temperature difference,° C, (°F)
T = temperature of guard heater, °C, °F
g
T = temperature of guard heater, °C, (°F)
g
T = temperature of upper heater, °C, °F
u
T = temperature of upper heater, °C, (°F)
u
T = temperature of lower heater, °C, °F
l
T = temperature of lower heater, °C, (°F)
l
T = temperature of one surface of the specimen, °C, °F
T = temperature of one surface of the specimen, °C, (°F)
T = temperature of the other surface of the specimen, °C, °F
T = temperature of the other surface of the specimen, °C, (°F)
T = mean temperature of the specimen, °C, °F
m
T = mean temperature of the specimen, °C, (°F)
m
s = unknown specimen
r = known calibration or reference specimen
o = contacts
4. Summary of Test Method
4.1 A specimen and a heat flux transducer (HFT) are sandwiched between two flat plates controlled at different temperatures,
to produce a heat flow through the test stack. A reproducible load is applied to the test stack by pneumatic or hydraulic means,
to ensure that there is a reproducible contact resistance between the specimen and plate surfaces. A cylindrical guard surrounds
the test stack and is maintained at a uniform mean temperature of the two plates, in order to minimize lateral heat flow to and from
the stack. At steady-state, the difference in temperature between the surfaces contacting the specimen is measured with temperature
sensors embedded in the surfaces, together with the electrical output of the HFT. This output (voltage) is proportional to the heat
flow through the specimen, the HFT and the interfaces between the specimen and the apparatus. The proportionality is obtained
through prior calibration of the system with specimens of known thermal resistance measured under the same conditions, such that
contact resistance at the surface is made reproducible.
5. Significance and Use
5.1 This test method is designed to measure and compare thermal properties of materials under controlled conditions and their
ability to maintain required thermal conductance levels.
6. Apparatus
6.1 A schematic rendering of a typical apparatus is shown in Fig. 1. The relative position of the HFT to sample is not important
(it may be on the hot or cold side) as the test method is based on maintaining axial heat flow with minimal heat losses or gains
radially. It is also up to the designer whether to choose heat flow upward or downward or horizontally, although downward heat
flow in a vertical stack is the most common one.
6.2 Key Components of a Typical Device:
6.2.1 The compressive force for the stack is to be provided by either a regulated pneumatic or hydraulic cylinder (1) or a spring
loaded mechanism. In either case, means must be provided to ensure that the loading can be varied and set to certain values
reproducibility.
´1
D6744 − 06 (2017)
FIG. 1 Key Components of a Typical Device
6.2.2 The loading force must be transmitted to the stack through a gimball joint (2) that allows up to 5° swivel in the plane
perpendicular to the axis of the stack.
6.2.3 Suitable insulator plate (3) separates the gimball joint from the top plate (4).
6.2.4 The top plate (assumed to be the hot plate for the purposes of this description) is equipped with a heater (5) and control
thermocouple (6) adjacent to the heater, to maintain a certain desired temperature. (Other means of producing and maintaining
temperature may also be used as long as the requirements under 6.3 are met.) The construction of the top plate is such as to ensure
uniform heat distribution across its face contacting the sample (8). Attached to this face (or embedded in close proximity to it),
in a fashion that does not interfere with the sample/plate interface, is a temperature sensor (7) (typically a thermocouple,
thermistor) that defines the temperature of the interface on the plate side.
6.2.5 The sample (8) is in direct contact with the top plate on one side and an intermediate plate (9) on the other side.
6.2.6 The intermediate plate (9) is an optional item. Its purpose is to provide a highly conductive environment to the second
temperature sensor (10), to obtain an average temperature of the surface. If the temperature sensor (10) is embedded into the face
of the HFT, or other means are provided to define the temperature of the surface facing the sample, the use of the intermediate
plate is not mandatory.
6.2.7 Heat flux transducer (HFT) is a device that will generate an electrical signal in proportion to the heat flux across it. The
level of output required (sensitivity) greatly depends on the rest of the instrumentation used to read it. The overall performance
of the HFT and its readout instrumentation shall be such as to meet the requirements in Section 13.
6.2.8 The lower plate (12) is constructed similarly to the upper plate (4), except it is positioned as a mirror image.
6.2.9 An insulator plate (16) separates the lower plate (12) from the heat sink (17). In case of using circulating fluid in place
of a heater/thermocouple arrangement in the upper and/or lower plates, the heat sink may or may not be present.
6.2.10 The entire stack is surrounded by a cylindrical guard (18) equipped with a heater (19) and a control thermocouple (20)
to maintain it at the mean temperature between the upper and lower plates. A small, generally unfilled gap separates the guard from
the stack. For instruments limited to operate in the ambient region, no guard is required. A draft shield is recommended in place
of it.
NOTE 2—It is permissible to use thin layers of high conductivity grease or elastomeric material on the two surfaces of the specimen to reduce the
thermal resistance of the interface and promote uniform thermal contact across the interface area.
NOTE 3—The cross sectional area of the specimen may be any, however, most commonly circular and rectangular cross sections are used. Minimum
size is dictated by the magnitude of the disturbance caused by thermal sensors in relation to the overall flux distribution. The most common sizes are 25
mm 25 mm round or square to 50 mm 50 mm round.
6.3 Requirements:
6.3.1 Temperature control of upper and lower plate is to be 6 0.1 °C (6 0.18 °F) 60.1 °C (6 0.18 °F) or better.
´1
D6744 − 06 (2017)
6.3.2 Reproducible load of 0.28 MPa (40 psi) 0.28 MPa (40 psi) has been found to be satisfactory for solid specimens. Minimum
load shall not be below 0.07 MPa (10 psi).0.07 MPa (10 psi).
6.3.3 Temperature sensors are usually fine gagegauge or small diameter sheath thermocouples, however, ultraminiature
resistance thermometers and linear thermistors may also be used.
6.3.4 Operating range of a device using a mean temperature guard shall be limited to − 100 °C to 300 °C, −100 °C to 300 °C,
when using thermocouples as temperature sensors, and − 180 °C to 300 °C −180 °C to 300 °C with platinum resistance
thermometers.
7. Test Specimen
7.1 The specimen to be tested shall be representative for the sample material. The recommended specimen configuration is a
50.8 6 0.25 mm (2 6 0.010 in.) 50.8 mm 6 0.25 mm (2 in. 6 0.010 in.) diameter disk, having smooth flat and parallel faces, 6
0.025 mm (6 0.001 in.), 60.025 mm (60.001 in.), such that a uniform thickness within 0.025 mm (6 0.001 in.) 0.025 mm (6
0.001 in.) is attained in the range from 12.7 to 25.4 mm (0.5 to 1.0 in.)12.7 mm to 25.4 mm (0.5 in. to 1.0 in.)
8. Sampling and Conditioning
8.1 Cut representative test specimens from larger pieces of the sample material or body.
8.2 Condition the cut specimens in accordance with the requirements of the appropriate material specifications, if any.
9. Calibration
9.1 Select the mean temperature and load conditions required. Adjust the upper heater temperature (T ) and lower heater
u
temperature (T ) such that the temperature difference at the required mean temperature is no less than 3030 °C to 35 °C 35 °C and
l
the specimen ΔT is not less than 3 °C. 3 °C. Adjust the guard heater temperature (T ) such that it is at approximately the average
g
of T and T .
u l
9.2 Select at least two calibration specimens having thermal resistance values that bracket the range expected for the test
specimens at the temperature conditions required.
9.3 Table 1 contains a list of several available materials commonly used for calibration, together with corresponding thermal
resistance (R ) values for a given thickness. This information is provided to assist the user in selecting optimum specimen thickness
s
for testing a material and in deciding which calibration specimens to use.
9.4 The range of thermal conductivity for which this test method is most suitable is such that the optimum thermal resistance
−4 −4 −2
range is from 10 × 10 to 400 × 10 m ·K/W. The most commonly used calibration materials are the Pyrex 7740, Pyroceram
9606, and stainless steel.
9.5 Measure the thickness of the specimen to 25 μm.25 μm.
9.6 Coat both surfaces of a calibration specimen with a very thin layer of a compatible heat sink compound or place a thin layer
of elastomeric heat transfer medium on it to help minimize the thermal resistance at the interfaces of adjacent contacting surfaces.
9.7 Insert the calibration specimen into the test chamber. Exercise care to ensure that all surfaces are free of any foreign matter.
9.8 Close the test chamber and clamp the calibration specimen in position between the plates at the recommended compressive
load of 0.28 MPa.0.28 MPa.
9.9 Wait for therm
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.