Thermal conductivity measuring method and measuring device

Abstract

The invention belongs to the technical field of micro-nano-scale thermal measurement, and particularly relates to a thermal conductivity measuring method and a measuring device.The thermal conductivity measuring method comprises the steps that a heat sink, a plurality of micro-nano devices and a to-be-measured sample are provided, the micro-nano devices have first thermal resistance, and the to-be-measured sample has second thermal resistance; contact thermal resistance is formed between the to-be-tested sample and the heat sink as well as between the to-be-tested sample and each contact area, and the first thermal resistance is greater than the second thermal resistance and greater than the contact thermal resistance; applying heating power to the thermal measurement circuit of the first micro-nano device; acquiring actual contact temperatures of the to-be-tested sample and contact areas of the second micro-nano device and the third micro-nano device adjacent to the to-be-tested sample; acquiring the actual heat flow power of a part which flows through the to-be-tested sample and corresponds to the part between the second micro-nano device and the third micro-nano device; calculating the thermal conductivity of the to-be-detected sample; and calculating the thermal conductivity of the to-be-tested sample according to the geometric dimension and the thermal conductivity of the to-be-tested sample. The device can eliminate the influence of contact thermal resistance, improves the measurement precision, is simple in structure, is low in cost, and is suitable for batch production.

Description

Technical Field

[0001] The present application relates to the technical field of micro-nanoscale thermal measurement, and more specifically, to a thermal conductivity measurement method and a measurement device. Background Art

[0002] With the development of micro-nano technology, new fibers, carbon nanotubes, semiconductor quantum dots, superlattices, nanoparticles and other materials are increasingly widely used in aerospace, detection, energy conversion, medicine and health. In the application field of nanotechnology, thermal properties are important properties of nanomaterials. The measurement and characterization of thermal parameters such as thermal conductivity, thermal diffusivity, and specific heat capacity of materials at micro / nano scales are important means to study microscopic phonon motion, heat transport, and defects. As the characteristic size of the material is reduced to the micron or even nanometer level, its thermal conductivity, thermal diffusivity, and even other thermal parameters also show obvious differences, that is, there is an obvious scale effect. Due to the small thickness of low-dimensional materials, surface thermal radiation has a greater impact on thermal conductivity measurement. Traditional thermal conductivity test methods for macroscopic materials, such as hot wire method, flash method, photothermal reflection emission, photoacoustic method, etc., are no longer suitable for the measurement of thermal conductivity of low-dimensional materials, and the thermal conductivity measurement methods in related technologies have the defect of poor measurement accuracy due to contact thermal resistance. Summary of the invention

[0003] The purpose of the present application is to provide a thermal conductivity measurement method and device, which can eliminate the influence of contact thermal resistance, improve the measurement accuracy of materials at the micro / nano scale, and have a simple structure, low cost, and are suitable for mass production.

[0004] In a first aspect, an embodiment of the present application provides a thermal conductivity measurement method, including: providing a heat sink, a plurality of micro-nano devices and a sample to be tested, wherein the heat sink has a cavity of a preset length, and a contact area and a thermal measurement circuit electrically connected to the contact area are arranged on the micro-nano device; the plurality of micro-nano devices are arranged on the heat sink at intervals along the length direction of the cavity, one end of the sample to be tested is contacted with the heat sink, and the other end of the sample to be tested is contacted with the contact areas of the plurality of micro-nano devices at different positions along its own length direction, wherein the micro-nano device has a first thermal resistance, the sample to be tested has a second thermal resistance, contact thermal resistances are formed between the sample to be tested and the heat sink, and between the sample to be tested and each contact area, the first thermal resistance is greater than the second thermal resistance, and the first thermal resistance is greater than the contact Thermal resistance; forming a temperature gradient along the length direction of the sample to be tested by applying heating power Q to the thermal measurement circuit of the first micro-nano device; obtaining the actual contact temperatures T2 and T3 of the contact areas of the sample to be tested with the adjacent second micro-nano device and the third micro-nano device respectively; obtaining the actual heat flow power Q0 flowing through the sample to be tested corresponding to the portion between the second micro-nano device and the third micro-nano device; calculating the thermal conductivity G=Q0 / (T3-T2) of the sample to be tested based on the actual heat flow power Q0 and the actual contact temperatures T2 and T3; calculating the thermal conductivity λ=G×L / S of the sample to be tested based on the geometric dimensions and thermal conductivity of the sample to be tested, wherein L is the length of the sample to be tested and S is the cross-sectional area of ​​the sample to be tested.

[0005] In addition, the thermal conductivity measurement method according to the present application may also have the following additional technical features:

[0006] In some embodiments of the present application, a ratio of the first thermal resistance to the second thermal resistance is greater than 20, and a ratio of the first thermal resistance to the contact thermal resistance is greater than 20.

[0007] In some embodiments of the present application, the first thermal resistance is greater than 10 6 K / W, the second thermal resistance and contact thermal resistance are both less than 5×10 4 K / W.

[0008] In some embodiments of the present application, the distance between the second micro-nano device and the third micro-nano device is greater than 10 times the diameter of the outer contour dimension of the cross section of the sample to be tested.

[0009] In some embodiments of the present application, the actual heat flow power Q0≈Q; and / or, the actual contact temperature T2≈T2' between the contact area of ​​the sample to be tested and the second micro-nano device, and the actual contact temperature T3≈T3' between the contact area of ​​the sample to be tested and the third micro-nano device, wherein T2' and T3' are the temperatures measured by the respective thermal measurement circuits of the second micro-nano device and the third micro-nano device, respectively.

[0010] In some embodiments of the present application, the actual heat flow power Q0=Q-Q', where Q' is the sum of the heat power lost by the first micro-nano device and the second micro-nano device; the actual contact temperatures between the sample to be tested and the second micro-nano device and the third contact area are T2=T2'×(R2'+R0) / R0, T3=T3'×(R3'+R0) / R0, where T2' and T3' are the temperatures measured by the thermal measurement circuit of the second micro-nano device, T3' is the temperature measured by the thermal measurement circuit of the third micro-nano device, R2' is the contact thermal resistance formed by the contact between the sample to be tested and the second micro-nano device, R3' is the contact thermal resistance formed by the contact between the sample to be tested and the third micro-nano device, and R0 is the first thermal resistance.

[0011] In some embodiments of the present application, the sum of the heat power lost by the first micro-nano device and the second micro-nano device is Q'=Q1'+Q2', wherein the heat power lost by the first micro-nano device is Q1', and Q1'=T1'×R0, T1' is the temperature measured by the thermal measurement circuit of the first micro-nano device; the heat power lost by the second micro-nano device is Q2', and Q2'=T2'×R0.

[0012] In some embodiments of the present application, the contact thermal resistance formed by the contact between the sample to be tested and the second micro-nano device is: R2'=(T 2测 -T 1测 ) / Q 2测 The contact thermal resistance formed by the contact between the sample to be tested and the third micro-nano device is: R3'=(T 3测 -T 2测 ) / Q 3测 , where Q 2测 is the test power applied to the second micro-nano device, T 1测 , T 2测 are the temperatures measured by the thermal measurement circuits of the first micro-nano device and the second micro-nano device at this time; Q 3测 is the test power applied to the third micro-nano device, T 2测 , T 3测 These are the temperatures measured by the thermal measurement circuits of the second micro-nano device and the third micro-nano device at this time respectively.

[0013] In some embodiments of the present application, the contact between the sample to be tested and the heat sink and the contact between the sample to be tested and the contact area of ​​each micro-nano device includes any one of direct contact, organic solvent immersion-drying optimized contact, and thermal interface material enhanced contact.

[0014] In a second aspect, an embodiment of the present application provides a thermal conductivity measuring device, comprising: a heat sink having a cavity of a preset length; a plurality of micro-nano devices arranged on the heat sink at intervals along the length direction of the cavity, a contact area and a thermal measurement circuit electrically connected to the contact area being provided on the micro-nano device, one end of a sample to be measured is in contact with the heat sink, and different positions of the sample to be measured along its own length direction are in contact with corresponding contact areas of the plurality of micro-nano devices, wherein the micro-nano device has a first thermal resistance, the sample to be measured has a second thermal resistance, contact thermal resistances are formed between the sample to be measured and the heat sink, and between the sample to be measured and each contact area, the first thermal resistance is greater than the second thermal resistance, and the first thermal resistance is greater than the contact thermal resistance.

[0015] According to the thermal conductivity measurement method and device provided in the embodiments of the present application, the heat flow test and the temperature test are decoupled, and the first thermal resistance of the micro-nano device itself is used to be greater than the second thermal resistance of the sample to be tested and the contact thermal resistance between the two, so as to ensure the accuracy of the heat flow and temperature measurement through the sample to be tested, thereby eliminating the influence of the contact thermal resistance and improving the measurement accuracy of materials at the micro / nano scale. The method and device have a simple structure, low cost, and are suitable for mass production.

[0016] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. In addition, the same reference numerals are used throughout the accompanying drawings to represent the same components. Among them:

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. In addition, the same reference numerals are used throughout the accompanying drawings to represent the same components. Among them:

[0019] Figure 1 This is a schematic structural diagram of a thermal conductivity measuring device according to an embodiment of the present application;

[0020] Figure 2 for Figure 1 A partial enlarged structural schematic diagram of a thermal conductivity measuring device shown;

[0021] Figure 3 This is a flowchart of the thermal conductivity measurement method according to an embodiment of the present application.

[0022] The reference numerals in the drawings are defined as follows:

[0023] 100, thermal conductivity measurement device;

[0024] 10, heat sink; 11, cavity; 20, micro-nano device; 21, contact area; 22, thermal measurement circuit;

[0025] 30, sample to be measured. Detailed implementation manners

[0026] The exemplary embodiments of the present application will be described in more detail below with reference to the drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application can be fully conveyed to those skilled in the art.

[0027] It should be understood that the terms used herein are for the purpose of describing specific exemplary embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" as used herein may also include the plural forms. The terms "comprising", "including", "containing", and "having" are inclusive and thus specify the presence of the stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the particular order described or illustrated, unless the order of performance is explicitly stated. It should also be understood that additional or alternative steps may be used.

[0028] Although the terms first, second, third, etc. may be used herein to describe multiple elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another. Unless the context clearly indicates otherwise, terms such as "first" and "second" and other numerical terms used herein do not imply an order or sequence. Thus, the first element, component, region, layer, or section discussed below may be referred to as the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0029] For ease of description, spatial relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, then the elements described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or in other directions) and the spatial relative descriptors used in the text are interpreted accordingly.

[0030] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0032] Figure 1 is a schematic structural diagram of a thermal conductivity measuring device according to an embodiment of the present application, Figure 2 for Figure 1 A locally enlarged schematic diagram of the thermal conductivity measurement device is shown.

[0033] See also Figure 1 and Figure 2 The embodiment of the present application provides a thermal conductivity measuring device 100 for measuring the thermal conductivity of a sample 30 to be tested. The thermal conductivity measuring device 100 includes a heat sink 10 and a plurality of micro-nano devices 20.

[0034] The heat sink 10 has a cavity 11 of a preset length. The temperature of the heat sink 10 does not change with the amount of heat energy transferred to it, which can be an object such as the atmosphere and the earth. In this embodiment, the material of the heat sink 10 can be a micro heat sink for cooling electronic chips. The heat sink 10 has a high thermal conductivity to the ground, and the thermal conductivity can be greater than 1mW / K.

[0035] A plurality of micro-nano devices 20 are arranged on the heat sink 10 at intervals along the length direction of the cavity 11, and a contact area 21 and a thermal measurement circuit 22 electrically connected to the contact area 21 are arranged on the micro-nano device 20. The material of the micro-nano device 20 may be a silicon nitride film, and the thermal measurement circuit 22 is used to apply heat to the micro-nano device 20 and also to measure the temperature of an object in contact with the contact area 21.

[0036] One end of the sample to be tested 30 contacts the heat sink 10, and the other end of the sample to be tested 30 contacts correspondingly with the contact areas 21 of multiple micro-nano devices 20 at different positions along its length direction, wherein the micro-nano device 20 has a first thermal resistance, and the sample to be tested 30 has a second thermal resistance. Contact thermal resistances are formed between the sample to be tested 30 and the heat sink 10 and between the sample to be tested 30 and each contact area 21, respectively, and the first thermal resistance is greater than the second thermal resistance, and the first thermal resistance is greater than the contact thermal resistance.

[0037] In this embodiment, the number of micro-nano devices 20 is at least three, at least one micro-nano device 20 is used to apply heating power, and the heating current can be a direct current or an alternating current. At least two micro-nano devices 20 are used to measure the temperature of the sample 30 to be tested that is in contact with the contact area 21. The material of the sample 30 to be tested can be any one of platinum, gold, silver, and intrinsic silicon, and the cross-sectional shape of the sample 30 to be tested can be circular or polygonal.

[0038] Optionally, one end of the sample 30 to be tested is in contact with the heat sink 10 through a heat conductive adhesive such as silver glue to improve the conductivity between the sample 30 to be tested and the heat sink 10. The sample 30 to be tested is in contact with the contact areas 21 of the multiple micro-nano devices 20 at different positions along its length direction. Optionally, the contact between the sample 30 to be tested and the heat sink 10 and the contact area 21 of the micro-nano device 20 include any one of direct contact, organic solvent immersion-drying optimized contact, and thermal interface material enhanced contact.

[0039] Optionally, the resistance of the contact area 21 of the micro-nano device 20 is 1 kΩ to 50 kΩ. Optionally, the resistance of the contact area 21 is 35 kΩ to 50 kΩ. This arrangement can ensure that the first thermal resistance of the micro-nano device 20 itself is greater than the contact resistance formed between the contact area 21 and the sample 30 to be tested.

[0040] The thermal conductivity measurement method according to an embodiment of the present application is described in detail below with reference to the accompanying drawings, and is applied to the thermal conductivity measurement device 100 as described above.

[0041] Figure 3 This is a flowchart of the thermal conductivity measurement method according to an embodiment of the present application.

[0042] See also Figure 1 and Figure 3 A thermal conductivity measurement method provided in an embodiment of the present application includes the following steps S1 to S7.

[0043] Step S1: Provide a heat sink 10, a plurality of micro-nano devices 20 and a sample to be tested 30. The heat sink 10 has a cavity 11 of a preset length. The micro-nano device 20 is provided with a contact area 21 and a thermal measurement circuit 22 electrically connected to the contact area 21. The temperature of the heat sink 10 does not change with the amount of heat energy transferred to it, and it can be an object such as the atmosphere and the earth. In this embodiment, the material of the heat sink 10 can be a micro heat sink for cooling electronic chips. The heat sink 10 has a high thermal conductivity to the ground, and the thermal conductivity can be greater than 1mW / K.

[0044] Step S2: multiple micro-nano devices 20 are arranged on the heat sink 10 at intervals along the length direction of the cavity 11, one end of the sample 30 to be tested is contacted with the heat sink 10, and the other end of the sample 30 to be tested is contacted with the contact areas 21 of the multiple micro-nano devices 20 at different positions along its own length direction; wherein the micro-nano device 20 has a first thermal resistance, the sample 30 to be tested has a second thermal resistance, contact thermal resistances are formed between the sample 30 to be tested and the heat sink 10 and each contact area 21, the first thermal resistance is greater than the second thermal resistance, and the first thermal resistance is greater than the contact thermal resistance;

[0045] Step S3: forming a temperature gradient along the length direction of the sample 30 to be measured by applying a heating power Q to the thermal measurement circuit 22 of the first micro-nano device 20;

[0046] Step S4: obtaining actual contact temperatures T2 and T3 of the contact regions 21 of the sample 30 to be tested and the adjacent second micro-nano device 20 and third micro-nano device 20 respectively;

[0047] Step S5: obtaining the actual heat flow power Q0 flowing through the portion of the sample 30 to be tested corresponding to the portion between the second micro-nano device 20 and the third micro-nano device 20;

[0048] Step S6: Calculate the thermal conductivity G=Q0 / (T3-T2) of the sample 30 to be tested according to the actual heat flow power Q0, the actual contact temperatures T2 and T3;

[0049] Step S7: Calculate the thermal conductivity λ=G×L / S of the sample 30 to be tested according to the geometric dimensions and thermal conductivity of the sample 30 to be tested, wherein L is the length of the sample 30 to be tested, and S is the cross-sectional area of ​​the sample 30 to be tested.

[0050] In this embodiment, the number of micro-nano devices 20 is at least three, at least one micro-nano device 20 is used to apply heating power, and the heating current can be a direct current or an alternating current. At least two micro-nano devices 20 are used to measure the temperature of the sample 30 to be tested that is in contact with the contact area 21. Specifically, the thermal measurement circuit 22 of at least one micro-nano device 20 is used to apply heat to the micro-nano device 20, and the thermal measurement circuits 22 of at least two micro-nano devices 20 are used to measure the temperature of the sample 30 to be tested that is in contact with the contact area 21 of the micro-nano device 20.

[0051] like Figure 1 As shown, there are three micro-nano devices 20, and along the direction from right to left of the cavity 11 of the heat sink 10, the rightmost micro-nano device 20 is the first micro-nano device 20, the middle micro-nano device 20 is the second micro-nano device 20, and the leftmost micro-nano device 20 is the third micro-nano device 20. A temperature gradient along the length direction of the sample 30 to be tested is formed by applying a heating power Q to the thermal measurement circuit 22 of the first micro-nano device 20.

[0052] If the first thermal resistance of the micro-nano device 20 is much greater than the second thermal resistance of the sample 30 to be tested, and the first thermal resistance is much greater than the contact thermal resistance, the heat loss through the micro-nano device 20 can be ignored, and the heat loss through the micro-nano device 20 is related to its own first thermal resistance.

[0053] If the first thermal resistance of the micro-nano device 20 is greater than the second thermal resistance of the sample 30 to be tested, and the first thermal resistance is greater than the contact thermal resistance, for example, the ratio of the first thermal resistance to the second thermal resistance is greater than 20, and the ratio of the first thermal resistance to the contact thermal resistance is greater than 20, then the contact thermal resistance between the contact area 21 of the micro-nano device 20 and the sample 30 to be tested can be calculated based on the first thermal resistance of the micro-nano device 20 itself and the measured temperature, thereby calculating the heat loss through the micro-nano device 20, and obtaining the actual heat flow power Q0 through a certain section of the sample 30 to be tested, and the temperature difference between the two ends of the certain section of the sample 30 to be tested, and obtaining the thermal conductivity G of the sample 30 to be tested, and finally calculating the thermal conductivity λ of the sample 30 to be tested based on the geometric dimensions and thermal conductivity G of the sample 30 to be tested.

[0054] Therefore, the thermal conductivity measurement method of this embodiment decouples the heat flow test and the temperature test, and at the same time utilizes the first thermal resistance of the micro-nano device 20 itself to be much larger than the second thermal resistance of the sample 30 to be tested and the contact thermal resistance between the two, thereby ensuring the accuracy of the heat flow and temperature measurement through the sample 30 to be tested, thereby eliminating the influence of the contact thermal resistance and improving the measurement accuracy of materials at the micro / nano scale. It has a simple structure, low cost, and is suitable for mass production.

[0055] In some embodiments, the ratio of the first thermal resistance to the second thermal resistance is greater than 20, and the ratio of the first thermal resistance to the contact thermal resistance is greater than 20. For example, if the ratio of the first thermal resistance to the second thermal resistance is greater than 50, and the ratio of the first thermal resistance to the contact thermal resistance is greater than 50, the heat loss through the micro-nano device 20 can be ignored. This thermal resistance relationship can ensure that the heating power Q and the heat flow through the sample to be tested 30 have small errors, and the temperature value measured by the thermal measurement circuit 22 has a small error with the actual contact temperature of the sample to be tested 30.

[0056] In some embodiments, the first thermal resistance is greater than 10 6 K / W, the second thermal resistance and contact thermal resistance are both less than 5×10 4 K / W. For example, the first thermal resistance is 5×10 6 K / W, the second thermal resistance and contact thermal resistance are both 2×10 4 K / W, at this time the heat loss through the micro-nano device 20 can be ignored.

[0057] In some embodiments, the distance between the second micro-nano device 20 and the third micro-nano device 20 is greater than 10 times the diameter of the outer contour dimension of the cross section of the sample 30 to be tested.

[0058] like Figure 1 and Figure 2 As shown, the cross section of the sample 30 to be tested is circular, and the distance between the second micro-nano device 20 and the third micro-nano device 20 is greater than 10 times the diameter of the sample 30 to be tested, so that the influence of the radial temperature gradient of the sample 30 to be tested on the measurement result of the thermal conductivity λ can be ignored. It can be understood that when the cross section of the sample 30 to be tested is a polygon, the diameter of its outer contour dimension is the diameter of the circumscribed circle of the polygon.

[0059] In some embodiments, the actual heat flow power Q0≈Q; and / or, the actual contact temperature T2≈T2' between the sample to be tested 30 and the contact area 21 of the second micro-nano device 20, and the actual contact temperature T3≈T3' between the sample to be tested 30 and the contact area 21 of the third micro-nano device 20, wherein T2' and T3' are the temperatures measured by the thermal measurement circuits 22 of the second micro-nano device 20 and the third micro-nano device 20, respectively.

[0060] As mentioned above, if the ratio of the first thermal resistance of the micro-nano device 20 to the second thermal resistance of the sample 30 to be tested is greater than 50, the heat loss through the micro-nano device 20 can be ignored. In other words, a heating power Q is applied to the thermal measurement circuit 22 of the first micro-nano device 20 to form a temperature gradient along the length direction of the sample 30 to be tested, and at this time, the actual heat flow power Q0≈Q flowing through the portion of the sample 30 to be tested corresponding to the second micro-nano device 20 and the third micro-nano device 20.

[0061] In addition, the actual contact temperature between the sample to be tested 30 and the contact area 21 of the second micro-nano device 20 is T2, and T2 = T2'×(R2'+R0) / R0;

[0062] The actual contact temperature between the sample 30 to be tested and the contact area 21 of the third micro-nano device 20 is T3, and

[0063] T3 = T3' × (R3' + R0) / R0;

[0064] Among them, T2' and T3' are the temperatures measured by the thermal measurement circuits 22 of the second micro-nano device 20 and the third micro-nano device 20 respectively, R2' and R3' are the contact thermal resistances between the contact areas 21 of the second micro-nano device 20 and the third micro-nano device 20 and the sample to be tested 30 respectively, and R0 is the first thermal resistance of the micro-nano device 20.

[0065] Since the ratio of the first thermal resistance R0 to the contact thermal resistances R2 ′ and R3 ′ is greater than 50, T2 ≈ T2 ′ and T3 ≈ T3 ′.

[0066] Thus, according to the actual heat flow power Q0, the actual contact temperatures T2 and T3, the thermal conductivity of the sample 30 to be tested is calculated as G=Q0 / (T3-T2)=Q / (T3'-T2');

[0067] According to the geometric dimensions and thermal conductivity G of the sample 30 to be tested, the thermal conductivity λ=G×L / S of the sample 30 to be tested is calculated, wherein L is the length of the sample 30 to be tested, and S is the cross-sectional area of ​​the sample 30 to be tested.

[0068] In this embodiment, the sample 30 to be tested, whose materials are platinum, gold, silver, and intrinsic silicon and have different geometric sizes, is taken as an example. The thermal conductivity λ of the sample 30 to be tested is measured by the thermal conductivity measurement method as described above, and the measurement result is compared with the thermal conductivity λ recorded in relevant literature, as shown in Table 1.

[0069] Table 1

[0070]

[0071]

[0072] According to the thermal conductivity λ measured in Table 1 and the thermal conductivity λ recorded in relevant literature, it can be seen that the measurement error of the thermal conductivity λ is less than 5%, and the measurement accuracy is high.

[0073] The following describes a measurement method for calculating the thermal conductivity λ of the sample to be tested 30 in consideration of the heat loss flowing through the micro-nano device 20 .

[0074] In some embodiments, the actual heat flow power Q0=Q-Q', where Q' is the sum of the heat power lost by the first micro-nano device 20 and the second micro-nano device 20; the actual contact temperatures between the tested sample 30 and the contact areas 21 of the second micro-nano device 20 and the third micro-nano device 20 are T2=T2'×(R2'+R0) / R0, T3=T3'×

[0075] (R3'+R0) / R0, wherein T2' is the temperature measured by the thermal measurement circuit 22 of the second micro-nano device 20, T3' is the temperature measured by the thermal measurement circuit 22 of the third micro-nano device 20, R2' is the contact thermal resistance formed by the contact between the sample 30 to be tested and the second micro-nano device 20, R3' is the contact thermal resistance formed by the contact between the sample 30 to be tested and the third micro-nano device 20, and R0 is the first thermal resistance.

[0076] In this embodiment, according to steps S3 to S5 of the thermal conductivity measurement method, a temperature gradient along the length direction of the sample to be tested 30 is formed by applying a heating power Q to the thermal measurement circuit 22 of the first micro-nano device 20, and an actual heat flow power Q0=Q-Q' flowing through the sample to be tested 30 corresponding to the portion between the second micro-nano device 20 and the third micro-nano device 20 is obtained, and actual contact temperatures T2 and T3 between the sample to be tested 30 and the second micro-nano device 20 and the third contact area 21 are obtained. The actual contact temperatures T2 and T3 are related to the contact thermal resistance, the first thermal resistance and the temperature measured by the thermal measurement circuit 22.

[0077] Since the measurement method takes into account the heat loss flowing through the micro-nano device 20 and eliminates the influence of contact thermal resistance, the measurement accuracy of the thermal conductivity λ of the sample to be measured 30 can be improved.

[0078] In some embodiments, the sum of the heat power lost by the first micro-nano device 20 and the second micro-nano device 20 is Q'=Q1'+Q2', the heat power lost by the first micro-nano device 20 is Q1', and Q1'=T1'×R0, T1' is the temperature measured by the thermal measurement circuit 22 of the first micro-nano device 20, and the heat power lost by the second micro-nano device 20 is Q2', and Q2'=T2'×R0.

[0079] Since T1' is the temperature measured by the thermal measurement circuit 22 of the first micro-nano device 20, the data can be directly read; R0 is the first thermal resistance of the first micro-nano device 20, the heat power lost by the first micro-nano device 20 can be calculated as Q1'. Similarly, the heat power lost by the first micro-nano device 20 can be calculated as Q2', and thus the sum of the lost heat power Q' can be calculated.

[0080] In some embodiments, the contact thermal resistance formed by the contact between the sample to be tested 30 and the second micro-nano device 20 is:

[0081] R2'=(T 2测 -T 1测 ) / Q 2测 , the contact thermal resistance formed by the contact between the sample to be tested 30 and the third micro-nano device 20 is:

[0082] R3'=(T 3测 -T 2测 ) / Q 3测 ,

[0083] Among them, Q 2测 is the test power applied to the second micro-nano device 20, T 1测 , T 2测 are the temperatures measured by the thermal measurement circuits 22 of the first micro-nano device 20 and the second micro-nano device 20 at this time; Q 3测 is the test power applied to the third micro-nano device 20, T 2测 , T 3测 These are the temperatures measured by the thermal measurement circuits 22 of the second micro-nano device 20 and the third micro-nano device 20 at this time.

[0084] According to the calculated contact thermal resistances R2′ and R3′ of the second micro-nano device 20 and the third micro-nano device 20 , the actual contact temperatures T2 and T3 between the tested sample 30 and the contact regions 21 of the second micro-nano device 20 and the third micro-nano device 20 can be obtained.

[0085] According to the calculated actual heat flow power Q0 = Q-Q', the actual contact temperatures T2 and T3, the thermal conductivity of the sample 30 to be tested is calculated as G = Q0 / (T3-T2) = Q / (T 3测 -T 2测 );

[0086] According to the geometric dimensions and thermal conductivity G of the sample 30 to be tested, the thermal conductivity λ=G×L / S of the sample 30 to be tested is calculated, wherein L is the length of the sample 30 to be tested, and S is the cross-sectional area of ​​the sample 30 to be tested.

[0087] In this embodiment, the sample 30 to be tested, whose materials are platinum, gold, silver, and intrinsic silicon and have different geometric sizes, is taken as an example. The thermal conductivity λ of the sample 30 to be tested is measured by the thermal conductivity measurement method as described above, and the measurement result is compared with the thermal conductivity λ recorded in relevant literature, as shown in Table 2.

[0088] Table 2:

[0089]

[0090]

[0091] According to the thermal conductivity λ measured in Table 2 and the thermal conductivity λ recorded in relevant literature, since the measurement method takes into account the heat loss flowing through the micro-nano device 20 and eliminates the influence of contact thermal resistance, the measurement error of the thermal conductivity λ of the sample 30 to be tested is less than 3%, and the measurement accuracy is higher.

[0092] The thermal conductivity measurement device and thermal conductivity measurement method of the embodiment of the present application decouple the heat flow test and the temperature test, and utilize the first thermal resistance of the micro-nano device 20 itself to be much larger than the second thermal resistance of the sample 30 to be tested and the contact thermal resistance between the two, thereby ensuring the accuracy of the heat flow and temperature measurement through the sample 30 to be tested, thereby eliminating the influence of the contact thermal resistance and improving the measurement accuracy of materials at the micro / nano scale. The device and method have a simple structure, low cost, and are suitable for mass production.

[0093] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for measuring thermal conductivity, characterized in that: include: A heat sink, a plurality of micro-nano devices and a sample to be tested are provided, wherein the heat sink has a cavity of a preset length, and the micro-nano device is provided with a contact area and a thermal measurement circuit electrically connected to the contact area; A plurality of the micro-nano devices are arranged on the heat sink at intervals along the length direction of the cavity, one end of the sample to be tested is brought into contact with the heat sink, and the other end of the sample to be tested is brought into contact with the contact regions of the plurality of micro-nano devices at different positions along its length direction; wherein the micro-nano device has a first thermal resistance, the sample to be tested has a second thermal resistance, contact thermal resistances are formed between the sample to be tested and the heat sink and between the sample to be tested and each of the contact regions, the first thermal resistance is greater than the second thermal resistance, and the first thermal resistance is greater than the contact thermal resistance; Forming a temperature gradient along the length direction of the sample to be measured by applying a heating power Q to the thermal measurement circuit of the first micro-nano device; Obtaining actual contact temperatures T2 and T3 of the contact areas of the sample to be tested and the adjacent second micro-nano device and third micro-nano device respectively; Obtaining actual heat flow power Q0 flowing through the portion of the sample to be tested corresponding to the portion between the second micro-nano device and the third micro-nano device; Calculate the thermal conductivity G=Q0 / (T3-T2) of the sample to be tested according to the actual heat flow power Q0, the actual contact temperatures T2 and T3; According to the geometric dimensions of the sample to be tested and the thermal conductivity, the thermal conductivity λ=G×L / S of the sample to be tested is calculated, wherein L is the length of the sample to be tested and S is the cross-sectional area of ​​the sample to be tested.

2. The thermal conductivity measurement method according to claim 1, characterized in that: A ratio of the first thermal resistance to the second thermal resistance is greater than 20, and a ratio of the first thermal resistance to the contact thermal resistance is greater than 20.

3. The thermal conductivity measurement method according to claim 2, characterized in that: The first thermal resistance is greater than 10 6 K / W, the second thermal resistance and the contact thermal resistance are both less than 5×10 4 K / W.

4. The thermal conductivity measurement method according to claim 1, characterized in that: The distance between the second micro-nano device and the third micro-nano device is greater than 10 times the diameter of the outer contour dimension of the cross section of the sample to be tested.

5. The thermal conductivity measurement method according to any one of claims 1 to 4, characterized in that: The actual heat flow power Q0≈Q; and / or, the actual contact temperature T2≈T2' between the sample to be tested and the contact area of ​​the second micro-nano device, the actual contact temperature T3≈T3' between the sample to be tested and the contact area of ​​the third micro-nano device, wherein T2' and T3' are the temperatures measured by the thermal measurement circuits of the second micro-nano device and the third micro-nano device, respectively.

6. The thermal conductivity measurement method according to any one of claims 1 to 4, characterized in that: The actual heat flow power Q0=Q-Q', where Q' is the sum of the heat power lost by the first micro-nano device and the second micro-nano device; The actual contact temperatures between the contact areas of the sample to be tested and the second and third micro-nano devices are T2=T2'×(R2'+R0) / R0, T3=T3'×(R3'+R0) / R0, respectively, wherein T2' is the temperature measured by the thermal measurement circuit of the second micro-nano device, T3' is the temperature measured by the thermal measurement circuit of the third micro-nano device, R2' is the contact thermal resistance formed by the contact between the sample to be tested and the second micro-nano device, R3' is the contact thermal resistance formed by the contact between the sample to be tested and the third micro-nano device, and R0 is the first thermal resistance.

7. The thermal conductivity measurement method according to claim 6, characterized in that: The sum of the heat power lost by the first micro-nano device and the second micro-nano device is Q'=Q1'+Q2', wherein the heat power lost by the first micro-nano device is Q1', and Q1'=T1'×R0, T1' is the temperature measured by the thermal measurement circuit of the first micro-nano device; the heat power lost by the second micro-nano device is Q2', and Q2'=T2'×R0.

8. The thermal conductivity measurement method according to claim 6, characterized in that: The contact thermal resistance formed by the contact between the sample to be tested and the second micro-nano device is: R2’=(T 2测 -T 1测 ) / Q 2测 , The contact thermal resistance formed by the contact between the sample to be tested and the third micro-nano device is: R3’=(T 3测 -T 2测 ) / Q 3测 , Among them, Q 2测 is the test power applied to the second micro-nano device, T 1测 , T 2测 are the temperatures measured by the thermal measurement circuits of the first micro-nano device and the second micro-nano device at this time; Q 3测 is the test power applied to the third micro-nano device, T 2测 , T 3测 These are the temperatures measured by the thermal measurement circuits of the second micro-nano device and the third micro-nano device at this time.

9. The thermal conductivity measurement method according to claim 1, characterized in that: The contact between the sample to be tested and the heat sink and the contact between the sample to be tested and the contact area of ​​each micro-nano device includes any one of direct contact, organic solvent immersion-drying optimized contact, and thermal interface material enhanced contact.

10. A thermal conductivity measuring device, characterized in that: include: A heat sink having a cavity of a predetermined length; A plurality of micro-nano devices are arranged on the heat sink at intervals along the length direction of the cavity, a contact area and a thermal measurement circuit electrically connected to the contact area are arranged on the micro-nano device, one end of the sample to be tested is in contact with the heat sink, and the other end of the sample to be tested is in contact with the contact areas of the plurality of micro-nano devices at different positions along its length direction, wherein the micro-nano device has a first thermal resistance, the sample to be tested has a second thermal resistance, contact thermal resistances are formed between the sample to be tested and the heat sink and between the sample to be tested and each of the contact areas, the first thermal resistance is greater than the second thermal resistance, and the first thermal resistance is greater than the contact thermal resistance.

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