CN115479970A - System and method for testing heat conductivity coefficient - Google Patents
System and method for testing heat conductivity coefficient Download PDFInfo
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Abstract
The invention discloses a system and a method for testing heat conductivity coefficient. The system comprises: the device comprises a sample to be detected, a sample placing table, a laser source module, an oscilloscope, a current source module and a data processing module; a sample to be detected is placed on the sample placing table and is enabled to be parallel to and opposite to the laser source module, and the laser source module emits nanosecond laser to irradiate the preset surface of the sample to be detected; the current source module is electrically connected with a sample to be detected; the oscilloscope is electrically connected with the sample to be measured and the data processing module, and is used for acquiring resistance change data of the sample to be measured under the irradiation of the laser source module and transmitting the resistance change data to the data processing module; the data processing module is used for collecting and processing resistance change data to obtain the heat conductivity coefficient of the sample to be measured. The temperature change of the rear surface of the sample to be measured caused by laser irradiation is measured by utilizing the relation between the metal conductivity and the temperature, so that the heat transfer capacity of heat in the normal direction of the sample to be measured is measured, the measuring operation process is simplified, and the measuring precision is improved.
Description
Technical Field
The embodiment of the invention relates to the technical field of semiconductors, in particular to a system and a method for testing a heat conductivity coefficient.
Background
With the rapid development of integration and miniaturization of energy systems, such as large-scale development and application of solar cell devices, battery systems, heaters, and the like, thermal management becomes one of the important factors affecting the reliability and energy efficiency of materials and devices. With the development of materials, thin film heat dissipation materials, especially micron-scale thin film materials such as graphene films, copper sheets and the like, are becoming the hot choice. The thermal conductivity of copper is about 400W/(mK), and the highest single-layer graphene can reach 5000W/(mK). In recent years, graphene-related materials have received much attention because of their extremely high thermal and electrical conductivity and high mechanical strength. Among them, free-standing graphene nanoplatelets or graphene papers have been studied by a large number of researchers for their high potential use in thermal management materials. The normal thermal properties are the most important factors for soaking materials, but it is difficult to measure the normal thermal conductivity of such films.
At present, the normal thermal conductivity coefficient test methods of the film material mainly comprise a laser flash method, a 3 omega method and the like. Typical commercial instruments are the relaxation-tolerant Laser Flash series test instruments. Laser Flash uses Laser Flash method to quickly and effectively measure the thermal conductivity of the material with temperature range of-125 deg.C-2800 deg.C and thermal conductivity of 0.1W/(mK) -2000W/(mK). However, this method cannot perform effective and accurate measurement for samples having a thickness of 20 μm or less. The 3 omega method can measure the thermal conductivity of a thin sample, but requires that the material is subjected to insulation treatment in advance, and has high requirements on the roughness of the surface of the material; meanwhile, the problems of temperature calibration, complex operation and error during later characterization exist.
Disclosure of Invention
The invention provides a system and a method for testing heat conductivity coefficient, which are used for measuring the temperature change of the rear surface of a sample to be tested caused by laser irradiation by utilizing the relationship between metal conductivity and temperature, thereby measuring the heat transfer capacity of heat in the normal direction of the sample to be tested, simplifying the measurement operation process and improving the measurement precision.
In a first aspect, an embodiment of the present invention provides a system for testing a thermal conductivity, including: the device comprises a sample to be detected, a sample placing table, a laser source module, an oscilloscope, a current source module and a data processing module;
the sample to be detected is placed on the sample placing table and is enabled to be parallel to and opposite to the laser source module, and the laser source module emits nanosecond laser to irradiate the preset surface of the sample to be detected;
the current source module is electrically connected with the sample to be detected and is used for providing direct current for the sample to be detected;
the oscilloscope is electrically connected with the sample to be detected and the data processing module, and is used for acquiring resistance change data of the sample to be detected under the irradiation of the laser source module and transmitting the resistance change data to the data processing module;
the data processing module is used for collecting and processing the resistance change data to obtain the heat conductivity coefficient of the sample to be measured.
Optionally, the sample to be detected is formed by sequentially laminating a target film to be detected, a polyester film and a metal coating.
Optionally, the current source module is connected to two ends of the metal coating through electrodes, and the current source module is configured to provide a direct current to the sample to be tested through the metal coating;
the oscilloscope is connected with the sample to be tested through the metal coating and is used for collecting resistance change data caused by temperature response of the metal coating after the target film is irradiated by laser light to obtain a temperature response curve.
Optionally, the thermal relaxation device further comprises a silicon photodiode, wherein the silicon photodiode is connected with the oscilloscope and is used for capturing laser pulses from the oscilloscope, and the positions of the laser pulses in the time scale are regarded as the starting time of thermal relaxation.
Optionally, the data processing module includes a thermal diffusivity calculating unit and a thermal conductivity calculating unit;
the thermal diffusivity calculation unit is used for calculating the thermal diffusivity of the target film to be measured according to a control equation of one-dimensional thermal transport in the multilayer film;
the thermal conductivity coefficient calculating unit is used for obtaining a numerical calculation result based on a one-dimensional heat transfer model, and the thermal conductivity coefficient of the target film to be measured is obtained through fitting the numerical calculation result and the temperature response curve.
Optionally, the system further comprises a vacuum chamber, the sample placement stage being placed in the vacuum chamber.
Optionally, the vacuum chamber further comprises a circulating cooling subsystem for providing a stable ambient temperature to the vacuum chamber.
In a second aspect, an embodiment of the present invention further provides a method for testing a thermal conductivity, where the method is applied to a system for testing a thermal conductivity according to any one of the first aspect, and the method includes:
placing a sample to be detected on a sample placing table, and connecting a current source and an oscilloscope, wherein the current source provides direct current for the sample;
irradiating nanosecond laser on a first preset surface of a sample to be detected through a laser source;
receiving resistance change data of a second preset surface of the sample to be detected under the nanosecond laser irradiation through the oscilloscope;
and collecting and processing the resistance change data to obtain the heat conductivity coefficient of the sample to be detected.
Optionally, before the sample to be tested is placed on the sample placing table, the method further includes:
sequentially laminating a target film to be detected, a polyester film and a metal coating to form the sample to be detected; the target film to be detected is a first preset surface, and the metal coating is a second preset surface.
Optionally, the collecting and processing the resistance change data to obtain the thermal conductivity of the sample to be tested includes:
collecting the resistance change data, and calculating according to a control equation of one-dimensional thermal transport in the multilayer film to obtain the thermal diffusivity of the target film to be detected;
and obtaining a numerical calculation result based on the one-dimensional heat transfer model, and fitting the numerical calculation result and the temperature response curve to obtain the heat conductivity coefficient of the target film to be measured.
The nanosecond laser is emitted by the laser source module to irradiate the preset surface of a sample to be measured placed on the placing table, the current source module is electrically connected with the sample to be measured and used for providing direct current for the sample to be measured, the oscilloscope is electrically connected with the sample to be measured, resistance change data of the sample to be measured under the irradiation of the laser source module are collected and transmitted to the data processing module for processing, and the heat conductivity coefficient of the sample to be measured is obtained; the method solves the problems that the measurement of the heat conductivity coefficient of a thin sample needs more complicated operation and has measurement errors, and realizes the measurement of the temperature change of the rear surface of the sample to be measured caused by laser irradiation by utilizing the relation between the metal conductivity and the temperature, thereby measuring the heat transfer capacity of heat in the normal direction of the sample to be measured, simplifying the measurement operation process and improving the measurement precision.
Drawings
Fig. 1A is a schematic structural diagram of a system for testing thermal conductivity according to an embodiment of the present invention;
fig. 1B is a schematic structural diagram of another thermal conductivity testing system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a sample to be tested in a thermal conductivity testing system according to an embodiment of the present invention;
fig. 3 is a schematic flow chart of a method for testing a thermal conductivity according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Example one
Fig. 1A is a schematic structural diagram of a thermal conductivity testing system according to an embodiment of the present invention, and as shown in fig. 1A, a thermal conductivity testing system 1 includes: the device comprises a sample to be detected 100, a sample placing table 200, a laser source module 300, an oscilloscope 400, a current source module 500 and a data processing module 600;
the sample 100 to be measured is placed on the sample placing table 200 and is made to face the laser source module 300 in parallel, and the laser source module 300 emits nanosecond laser to irradiate the preset surface of the sample 100 to be measured;
the current source module 500 is electrically connected to the sample 100 to be tested, and is configured to provide a direct current to the sample 100 to be tested;
the oscilloscope 400 is electrically connected to the sample 100 to be measured and the data processing module 600, and is configured to collect resistance change data of the sample 100 to be measured under the irradiation of the laser source module 300, and transmit the resistance change data to the data processing module 600;
the data processing module 600 is configured to collect and process the resistance change data to obtain the thermal conductivity of the sample 100 to be measured.
As shown in fig. 2, the sample 100 to be measured is formed by sequentially laminating a target film 110 to be measured, a polyester film 120, and a metal plating layer 130. Further, the metal plating layer 130 is ohmically connected to the two electrodes of the current source module 500 only by silver conductive paste to form a conductive loop, and the silver paste is used to enhance electrical and thermal contact between the metal plating layer and the electrodes.
The target film 110 used in this embodiment is partially reduced graphene paper PRGP, and since PRGP has conductivity, the target film 110 needs to be insulated first, and in this embodiment, the polyester film 120 with a thickness of 0.5 μm is used to separate the target film 110 from the metal plating 130, so as to meet the requirement of the nano metal plating 130 as a temperature detector.
The method comprises the steps that a sample 100 to be tested is fixedly and vertically placed on a sample placing table 200, the sample 100 to be tested is parallel to and opposite to a laser source module 300 and is connected with a current source module 500 and an oscilloscope 400, the preset surface of a target film 110 of the sample 100 to be tested faces the light source direction and is used for receiving laser irradiation, specifically, the current source module 500 is connected with two ends of a metal coating 130 through electrodes, and the current source module 500 is used for providing direct current for the sample to be tested through the metal coating 130; the oscilloscope 400 is connected to the sample 100 to be measured through the metal plating 130, and the oscilloscope 400 is used for acquiring resistance change data caused by temperature response of the metal plating 130 after the target film 110 is irradiated by laser light, so as to obtain a temperature response curve. When a test is started, the laser source module 300 is started to emit nanosecond laser to irradiate the preset surface of the target film 110 in the sample 100 to be tested, the target film 110 generates heat under the irradiation of the laser, the heat is conducted to the metal plating layer 130 through the polyester film 120, the temperature of the metal plating layer 130 is increased to cause the resistance of the metal plating layer 130 to change, and the oscilloscope 400 connected to the metal plating layer 130 displays the monitored voltage difference between the two ends of the metal plating layer 130. Illustratively, after a single laser pulse irradiates the target film 110, the temperature of the metallization 130 will increase from the initial experimental temperature to a maximum value and then return to the initial state as heat dissipates along the metallization 130, and the oscilloscope 400 receives the resistance change data and generates a waveform map of the corresponding changes. As shown in fig. 1B, the thermal conductivity test system 1 further includes a silicon photodiode 700, the silicon photodiode 700 is connected to the oscilloscope 400, and is configured to capture a laser pulse from the oscilloscope 400, a position of the laser pulse in a time scale is regarded as a start time of thermal relaxation, the photodiode 700 is further connected to the data processing module 600, and the start time of thermal relaxation is sent to the data processing module 600, where signal capture in a microsecond-level ultrafast thermal relaxation process is crucial and the test start time is accurately obtained.
The oscilloscope 400 transmits the resistance change data to the data processing module 600, and the data processing module 600 collects and processes the resistance change data to obtain the thermal conductivity of the sample 100 to be measured. The one-dimensional heat transmission in the sample 100 to be measured composed of the target film 110, the polyester film 120 and the metal coating 130 is simulated by using a numerical method to obtain a temperature response curve of the surface of the metal coating 130, and the curve is used for fitting experimental data to obtain the thermal diffusivity and the thermal conductivity of the target film 110.
The data processing module 600 includes a thermal diffusivity calculating unit 610 and a thermal conductivity calculating unit 620; the thermal diffusivity calculation unit 610 is configured to calculate a thermal diffusivity of the target thin film 110 to be measured according to a control equation of one-dimensional thermal transport in the multilayer film; the thermal conductivity coefficient calculating unit 620 is configured to obtain a numerical calculation result based on the one-dimensional heat transfer model, and obtain the thermal conductivity coefficient of the target film 110 to be measured by fitting the numerical calculation result and the temperature response curve.
In embodiments of the invention, due to the large difference in heat transfer characteristic times or characteristic lengths in both the normal and in-plane directions, heat can be reduced to one-dimensional transport in the cross-plane direction followed by diffusion in the in-plane direction.
The control equation for one-dimensional heat transport in the sample 100 to be measured in the embodiment of the present invention can be expressed as follows:
in the embodiment of the invention, the thickness of the high-heat-conduction nano metal coating is negligible relative to a single-layer film with a micron thickness. The governing equation in the embodiment of the present invention may be solved by using green's function, and when x = L and normalized from the initial temperature to the maximum temperature, the temperature change of the metal plating layer 130 on the rear surface of the sample 100 to be measured is expressed as:
in the embodiment of the present invention, the resistance of the metal plating layer 130 is linearly proportional to its temperature in a small temperature range, that is:
R＝(ρ 0 +γ·ΔT)×(l/A c )
where ρ is 0 Is the initial resistivity at the experimental temperature, gamma is the local temperature coefficient of resistivity, Δ T is the temperature rise, l is the sample length, A c Is the cross-sectional area of the metal coating.
According to the principles of embodiments of the present invention, R is derived from the initial value (R) before the laser pulse 0 ) Normalized to the maximum value (R) after the laser pulse m ) In time, there are:
in accordance with principles and measurements of embodiments of the present invention, thermal conductivity can be calculated from a given material density and specific heat as shown in the following equation:
k＝α·ρ·c p
the temperature response of the back metal plating 130 of the sample 100 to be measured can be directly detected by the voltage change caused by the resistance change using the oscilloscope 400, and the thermal diffusivity of the single-layer sample target film 110 can be determined by α = (1.37L) 2 /π 2 t 1/2 ) Can be directly obtained.
In the numerical simulation process, the thicknesses and heat capacities of the materials of the target film 110, the mylar 120, and the metal plating 130 are critical parameters, and the parameters of the mylar 120 and the metal plating 130 are known and obtained before the test. The interlayer interface thermal resistance of each layer is at least two orders of magnitude smaller than the self thermal resistance of the material, and can be ignored in the test method of the embodiment.
The nanosecond laser is emitted by the laser source module to irradiate the preset surface of a sample to be measured placed on the placing platform, the current source module is electrically connected with the sample to be measured and used for providing direct current for the sample to be measured, the oscilloscope is electrically connected with the sample to be measured, resistance change data of the sample to be measured under the irradiation of the laser source module are collected and transmitted to the data processing module to be processed, and the heat conductivity coefficient of the sample to be measured is obtained; the method solves the problems that the measurement of the heat conductivity coefficient of a thin sample to be measured needs more complicated operation and measurement errors exist, and realizes the measurement of the temperature change of the rear surface of the sample to be measured caused by laser irradiation by utilizing the relation between the metal conductivity and the temperature, thereby measuring the heat transfer capacity of heat in the normal direction of the sample to be measured, simplifying the measurement operation process and improving the measurement precision.
On the basis of the above technical solution, as shown in fig. 1B, further, the thermal conductivity testing system 1 further includes a vacuum chamber 800, and the sample placing stage 200 is placed in the vacuum chamber 800.
Further, the thermal conductivity testing system 1 further comprises a circulating cooling subsystem 2, and the circulating cooling subsystem 2 is used for providing a stable ambient temperature for the vacuum chamber 800.
In the embodiment of the present invention, the vacuum chamber 800 is used to reduce the heat dissipated by thermal convection after the laser irradiates and heats the surface of the target film 110, thereby reducing errors. The closed-cycle cooling subsystem 2 is utilized to ensure that the sample is at a constant temperature in the measurement process, and meanwhile, the influence of the stability of the environmental temperature on the measurement precision can be reduced, so that the effective measurement of the heat conduction performance at an extremely low temperature can be realized.
Further, the original laser spot size emitted by the laser source module 300 is about 3-5 cm, which is much larger than the lateral size of the sample 100 to be measured. Therefore, it can be safely assumed that the laser energy distribution of the preset surface of the sample to be measured is uniform, the laser is irradiated on the light path of the sample to be measured 100, and the laser is adjusted by the diaphragm, so that it can be ensured that the laser only irradiates the preset surface of the sample to be measured, and the interference of laser heating on the electrode and the wiring is reduced to a negligible level.
Example two
Fig. 3 is a schematic flow chart of a method for testing a thermal conductivity according to an embodiment of the present invention. The embodiment is applicable to the case of testing the normal thermal conductivity of a target film with a micrometer thickness, and the method can be executed by a thermal conductivity testing system, as shown in fig. 3, and specifically includes the following steps:
The method comprises the steps that a target film is conductive, so that the target film needs to be subjected to insulation treatment, and the target film to be detected, a polyester film and a metal coating are sequentially laminated to form a sample to be detected before the sample to be detected is placed on a sample placing table; the target film to be detected is a first preset surface, and the metal coating is a second preset surface. Further, the metal plating layer is ohmically connected to the two electrodes of the current source module only by silver conductive paste to form a conductive loop, and the silver paste is used to enhance electrical and thermal contact between the metal plating layer and the electrodes.
The method comprises the following steps that a sample to be tested is fixedly and vertically placed on a sample placing table, the sample to be tested is parallel to and opposite to a laser source module, and is connected with a current source module and an oscilloscope, specifically, the current source module is connected with two ends of a metal coating through electrodes, and the current source module is used for providing direct current for the sample to be tested through the metal coating; the oscilloscope is connected with a sample to be measured through the metal coating and is used for collecting resistance change data caused by temperature response of the metal coating after the target film is irradiated by laser light to obtain a temperature response curve.
When the test is started, the laser source module is started to emit nanosecond laser to irradiate the preset surface of the target film in the sample to be tested, the target film generates heat under the irradiation of the laser, and the heat is conducted to the metal coating through the polyester film.
Further, the method also comprises the following steps: the silicon photodiode was connected to an oscilloscope and the laser pulses were captured from the oscilloscope, and the position of the laser pulse in the time scale was taken as the starting time of thermal relaxation. The photodiode is also connected with the data processing module, the starting time of thermal relaxation is sent to the data processing module, signal capture in the microsecond-level ultra-fast thermal relaxation process is crucial, and the testing starting time is accurately acquired.
And 230, receiving resistance change data of a second preset surface of the sample to be detected, which is caused by the nanosecond laser irradiation of the first preset surface of the sample to be detected, through the oscilloscope.
After a single laser pulse irradiates the target film, the temperature of the metal coating will rise from the initial experimental temperature to a maximum value and then return to the initial state as heat dissipates along the metal coating. The temperature of the metal coating rises to cause the resistance of the metal coating to change, the oscilloscope connected to the metal coating displays the monitored voltage difference at two ends of the metal coating, and the oscilloscope receives resistance change data and generates a waveform diagram of strain.
And 240, collecting and processing the resistance change data to obtain the heat conductivity coefficient of the sample to be detected.
The one-dimensional heat transmission in a sample 100 to be tested consisting of the target film, the polyester film and the metal coating is simulated by using a numerical method to obtain a temperature response curve of the surface of the metal coating, and the experimental data is fitted by using the curve to obtain the thermal diffusivity and the thermal conductivity coefficient of the target film.
Wherein, step 240 specifically includes:
and 241, collecting the resistance change data, and calculating according to a control equation of one-dimensional thermal transport in the multilayer film to obtain the thermal diffusivity of the target film to be measured.
And 242, obtaining a numerical calculation result based on the one-dimensional heat transfer model, and fitting the numerical calculation result and the temperature response curve to obtain the heat conductivity coefficient of the target film to be measured.
In embodiments of the invention, due to the large difference in heat transfer characteristic times or characteristic lengths in both the normal and in-plane directions, heat can be reduced to one-dimensional transport in the cross-plane direction followed by diffusion in the in-plane direction.
The control equation of one-dimensional heat transport in the sample to be measured in the embodiment of the present invention can be expressed as follows:
in the embodiment of the invention, the thickness of the high-heat-conductivity nano metal plating layer is negligible relative to a single-layer film with a micrometer thickness. The control equation in the embodiment of the present invention can be solved by using a green's function, and when x = L and is normalized from the initial temperature to the maximum temperature, the temperature change of the metal plating layer on the rear surface of the sample to be measured is expressed as:
in the embodiment of the invention, the resistance of the metal coating is linearly proportional to the temperature thereof in a small temperature range, namely:
R＝(ρ 0 +γ·ΔT)×(l/A c )
where ρ is 0 Is the initial resistivity at the experimental temperature, gamma is the local temperature coefficient of resistivity, Δ T is the temperature rise, l is the sample length, A c Is the cross-sectional area of the metal coating.
According to the principles of embodiments of the present invention, R is derived from the initial value (R) prior to the laser pulse 0 ) Normalized to the maximum value (R) after the laser pulse m ) In time, there are:
in accordance with principles and measurements of embodiments of the present invention, thermal conductivity can be calculated from a given material density and specific heat as shown in the following equation:
k＝α·ρ·c p
the temperature response of the metal coating on the back of the sample to be detected can be directly detected by a voltage change caused by resistance change by using an oscilloscope, and the thermal diffusivity of the target film of the single-layer sample can be determined by alpha = (1.37L) 2 /π 2 t 1/2 ) Is directly obtained.
In the numerical simulation process, the thicknesses and heat capacities of materials of all layers of the target film, the polyester film and the metal coating are key parameters, and known parameters of the polyester film and the metal coating are obtained before testing. The interlayer interface thermal resistance of each layer is at least two orders of magnitude smaller than the self thermal resistance of the material, and can be ignored in the test method of the embodiment.
The nanosecond laser is emitted by the laser source module to irradiate the preset surface of a sample to be measured placed on the placing table, the current source module is electrically connected with the sample to be measured and used for providing direct current for the sample to be measured, the oscilloscope is electrically connected with the sample to be measured, resistance change data of the sample to be measured under the irradiation of the laser source module are collected and transmitted to the data processing module for processing, and the heat conductivity coefficient of the sample to be measured is obtained; the method solves the problems that the measurement of the heat conductivity coefficient of a thin sample to be measured needs complicated operation and has measurement errors, and realizes the measurement of the temperature change of the rear surface of the sample to be measured caused by laser irradiation by utilizing the relation between the metal conductivity and the temperature, thereby measuring the heat transfer capacity of heat in the normal direction of the sample to be measured, simplifying the measurement operation process and improving the measurement precision.
On the basis of the technical scheme, the method further comprises the steps of placing the sample placing table in the vacuum cavity, and providing stable environment temperature for the vacuum cavity by using the circulating cooling subsystem.
The vacuum cavity adopted in the embodiment of the invention can reduce the heat dissipated by heat convection after the laser irradiates and heats the surface of the target film, and reduce errors. The closed-cycle cooling subsystem is utilized to ensure that the sample is at a constant temperature in the measurement process, and meanwhile, the influence of the stability of the environmental temperature on the measurement precision can be reduced, so that the effective measurement of the heat conductivity at an extremely low temperature can be realized.
Furthermore, the original laser spot size emitted by the laser source module is about 3-5 cm, which is far larger than the transverse size of the sample to be measured. The laser energy distribution on the first preset surface is ensured to be uniform, the laser can be adjusted through the diaphragm, the laser is ensured to only irradiate the preset surface of the sample to be detected, and the interference of laser heating on the electrode and the wiring is reduced to a negligible level.
It is to be noted that the foregoing description is only exemplary of the invention and that the principles of the technology may be employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in some detail by the above embodiments, the invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the invention, and the scope of the invention is determined by the scope of the appended claims.
Claims (10)
1. A system for testing thermal conductivity, comprising: the device comprises a sample to be detected, a sample placing table, a laser source module, an oscilloscope, a current source module and a data processing module;
the sample to be detected is placed on the sample placing table and is enabled to be parallel to and opposite to the laser source module, and the laser source module emits nanosecond laser to irradiate the preset surface of the sample to be detected;
the current source module is electrically connected with the sample to be detected and is used for providing direct current for the sample to be detected;
the oscilloscope is electrically connected with the sample to be detected and the data processing module, and is used for acquiring resistance change data of the sample to be detected under the irradiation of the laser source module and transmitting the resistance change data to the data processing module;
the data processing module is used for collecting and processing the resistance change data to obtain the heat conductivity coefficient of the sample to be measured.
2. The system for testing the thermal conductivity according to claim 1, wherein the sample to be tested is formed by sequentially laminating a target film to be tested, a polyester film and a metal plating layer.
3. The system for testing the thermal conductivity according to claim 2, wherein the current source module is connected to two ends of the metal coating through electrodes, and the current source module is configured to provide a direct current to the sample to be tested through the metal coating;
the oscilloscope is connected with the sample to be tested through the metal coating and is used for collecting resistance change data caused by temperature response of the metal coating after the target film is irradiated by laser light to obtain a temperature response curve.
4. The system for testing thermal conductivity of claim 1, further comprising a silicon photodiode connected to the oscilloscope for capturing laser pulses from the oscilloscope, wherein the position of the laser pulses in the time scale is considered as the start time of thermal relaxation.
5. The system for testing thermal conductivity of claim 3, wherein the data processing module comprises a thermal diffusivity calculating unit and a thermal conductivity calculating unit;
the thermal diffusivity calculation unit is used for calculating the thermal diffusivity of the target film to be measured according to a control equation of one-dimensional thermal transport in the multilayer film;
the thermal conductivity coefficient calculation unit is used for obtaining a numerical calculation result based on a one-dimensional heat transfer model, and obtaining the thermal conductivity coefficient of the target film to be measured through fitting the numerical calculation result and the temperature response curve.
6. The system for testing thermal conductivity of claim 1, further comprising a vacuum chamber, wherein the sample placement stage is placed in the vacuum chamber.
7. The system for testing thermal conductivity of claim 6, further comprising a circulating cooling subsystem for providing a stable ambient temperature for the vacuum chamber.
8. A method for testing a thermal conductivity, which is applied to the system for testing a thermal conductivity according to any one of claims 1 to 7, comprising:
placing a sample to be detected on a sample placing table, and connecting a current source and an oscilloscope, wherein the current source provides direct current for the sample;
irradiating nanosecond laser on a first preset surface of a sample to be detected through a laser source;
receiving resistance change data of a second preset surface of the sample to be detected, which is caused by the nanosecond laser irradiation of the first preset surface, through the oscilloscope;
and collecting and processing the resistance change data to obtain the heat conductivity coefficient of the sample to be detected.
9. The method for testing thermal conductivity according to claim 8, further comprising, before placing the sample to be tested on the sample placement stage:
sequentially laminating a target film to be detected, a polyester film and a metal coating to form the sample to be detected; the target film to be detected is a first preset surface, and the metal coating is a second preset surface.
10. The method for testing thermal conductivity according to claim 8, wherein the collecting and processing the resistance change data to obtain the thermal conductivity of the sample to be tested comprises:
collecting the resistance change data, and calculating according to a control equation of one-dimensional thermal transport in the multilayer film to obtain the thermal diffusivity of the target film to be detected;
and obtaining a numerical calculation result based on the one-dimensional heat transfer model, and fitting the numerical calculation result and a temperature response curve to obtain the heat conductivity coefficient of the target film to be measured.
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| CN117849108A (en) * | 2024-03-07 | 2024-04-09 | 北京科技大学 | Contact type thermal conductivity measuring device and method |
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