Method for determination of thermal conductivity and thermal diffusivity of anisotropic materials

Abstract

The invention discloses a detection method for thermal conductivity and thermal diffusivity of an anisotropic material, which adopts signal frequency domain characteristics to detect the thermal conductivity and the thermal diffusivity of the anisotropic material by using a harmonic detection technology. According to the method, micro metal detectors with a certain sizes and shapes are arranged on a surface of an sample in different directions; the micro metal detectors are simultaneously adopted as temperature sensors; with adopting alternating current heating, three harmonic waves and fundamental waves of the micro metal detectors are detected through a lock-in amplifying technology; the thermal conductivities and the thermal diffusivities of the anisotropic material in different directions are determined according to a relation between the frequency response characteristics of the micro metal detectors and the temperature changes of the micro metal detectors. According to the present invention, with adopting the harmonic detection principle and the data treatment method, the thermal conductivities and the thermal diffusivities of the anisotropic material in the directions of x,y and z can be obtained according to the width and the arrangement localities of the micro metal detectors.

Description

technical field [0001] The invention relates to the field of measurement technology, and is a method for measuring the thermal conductivity and thermal diffusivity of anisotropic materials by using harmonic detection technology, especially a method for testing thermal and physical parameters of materials such as carbon nanotube arrays, thin films and crystals . Background technique [0002] The thermal conductivity and thermal diffusivity of anisotropic materials are closely related to orientation, and the measured results are very different for different orientations. Along the different directions of the lattice in the crystal, the periodicity and density of atomic arrangement are not the same, which leads to different thermal conductivity and thermal diffusivity of the crystal in different directions. The thickness of the film can reach the nanometer level, the length (width) thickness ratio is very large, and it has strong anisotropy. The accurate measurement of the the...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the technical defects such as the difficulty in describing the thermal conductivity and thermal diffusivity of anisotropic materials at present, and provide a method for measuring the thermal conductivity and thermal diffusivity of anisotropic materials using harmonic detection technology

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