Fig. 1 High-temperature thermal property test system based on 3ω technology: (a) High-temperature vacuum furnace, (b) Specimen fixture During the operation of aerospace vehicles, aerospace materials are often exposed to high temperatures or temperatures of several thousand degrees Celsius, and sometimes high-temperature abrupt changes occur. The thermal parameters of aerospace materials at high temperatures are designed to safely operate various types of spacecraft. The key data. However, traditional test systems and measurement methods cannot accurately measure the thermal physical properties of materials under high temperature. Based on this background, there is an urgent need to study methods and systems for accurate measurement of high temperature thermal properties of materials. Recently, scientists from the Research Center for Heat and Mass Transfer at the Institute of Engineering Thermophysics, Chinese Academy of Sciences, have developed high temperature thermal properties testing techniques and systems based on 3ω technology (as shown in Figure 1). The researchers first deposited a four-nanometer thick metal four-electrode structure on the sample to be measured, and then used a specially designed sample fixture to press the four-electrode structure and the molybdenum wire lead through the ceramic sheet. The test fixture was placed at high temperature during the test. Vacuum furnace on a specific base. High-temperature vacuum furnace uses induction heating, the maximum heating temperature up to 2500 °C, temperature control accuracy of up to 0.2%. The experimental system was used to measure the thermal conductivity of AlN ceramics from room temperature to 1100 K. The measurement results are in good agreement with the results of K. Watari et al., which shows that the system has high measurement accuracy in this temperature range. 2 is shown). On this basis, researchers further studied the thermal conductivity of germanate glass-ceramics as a function of temperature (as shown in Figure 3). The results show that the effective thermal conductivity of germanate glass-ceramics is dominated by phonon conduction and photons. The heat conduction decides together. The above work was supported by the National Natural Science Foundation of China and the National Basic Research Development Program ("973"). The research results have been published in International Journal of Thermophysics, 2014, 35(2): 336-345. Hp 500 Graphite Electrode,Hp Uhp Graphite Electrode,Graphite Electrode Hp Uhp,Steel Smelting Graphite Electrode Carbographite Industrial PTE.LTD , https://www.graphites.pl
Fig. 2 Verification of the temperature dependence of effective thermal conductivity of AlN ceramics 
Fig. 3 The relationship between the thermal conductivity of germanate glass ceramic and temperature