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基于微结构低温工程学 ,提出三维低温界面层的概念 ,指出界面热阻是制冷机直接冷却超导磁体需要解决的关键技术之一。以GM制冷机为冷源 ,按稳态热流法原理测量了Bi 2 2 2 3、AlN的热导率及它们之间的低温界面热阻。在 0 15MPa～ 0 5 5MPa压力范围内 ,AlN和Bi 2 2 2 3间的界面热阻随界面层温度和接触压力的升高而降低 ,并随接触界面处温度的不同表现出不同的变化率。当界面层Bi 2 2 2 3侧温度为 5 5K时 ,在 0 5 469MPa的接触压力作用下 ,Bi 2 2 2 3和AlN间的界面热阻是厚度为 10mm的AlN垫片体积热阻的 3 8 86倍 ,是接触压力 0 2 2 81MPa时界面热阻的 3 8 7%。
Based on the microstructure and low temperature engineering, the concept of three-dimensional low-temperature interface layer is proposed. It is pointed out that the interface thermal resistance is one of the key technologies to be solved in direct cooling of superconducting magnets. Based on the steady-state heat flow method, the thermal conductivity of Bi 2 2 2 3, AlN and the low-temperature interface thermal resistance between them were measured using a GM refrigerator as a cooling source. The thermal interface resistance between AlN and Bi 2 2 2 3 decreases with the increase of interfacial temperature and contact pressure in the pressure range of 0 15MPa ~ 0 55MPa, and shows different rate of change with the temperature at the interface . The interface thermal resistance between Bi 2 2 2 3 and AlN at a contact pressure of 5 469 MPa when the temperature at the side of the interface layer Bi 2 2 3 3 is 5 5 K is the volumetric thermal resistance of the AlN gasket with a thickness of 10 mm 8 86 times, is the contact pressure 0 2 2 81MPa interface thermal resistance 387%.