Experimental Study on Thermal Contact Resistance of Oxygen-free Copper Materials under Indium Sheet Filling at 4~5 K

In the successive deep space exploration missions, high-precision optical detection equipment requires a long-term stable cryogenic temperature working environment. The heat transfer interface has a certain heat transfer temperature difference due to the thermal resistance of the heat transfer medium, in order to ensure the working environment of the equipment, avoid serious consequences such as detection efficiency loss, accuracy decline and noise interference increase. The interfacial thermal contact resistance of two solid thermal conductive materials, oxygen-free copper and stainless steel, was experimentally tested at the deep cryogenic temperature zone. The contact thermal resistance of oxygen-free copper（Ra=3.2 ）and stainless steel-oxygen-free copper contact thermal resistance（Ra=3.2 ）were texted under the conditions of vacuum, 4~5.2 K, pressure of 3077 N and indium sheet as filler. The results show that the thermal contact resistance between oxygen-free copper interfaces is 10⁻⁵~10⁻⁴ m²· K/W magnitude, and decreases with the increase of temperature and the decrease of roughness. The contact thermal resistance between oxygen-free copper and stainless steel is in the order of 10⁻² m²· K/W magnitude.