Surface treatment technology of molybdenum foil for aerospace interconnecting sheets
Most spacecraft use solar-battery as the power supply system, during the light period, the solar array converts solar energy into electricity, providing electricity for the spacecraft's electrical load, while charging the battery bank. The solar array is actually composed of a certain number of solar cells through the series and parallel, these cells are orderly mounted on the panel, using the photoelectric effect to generate electricity. Because the panels need to be stretched and angled, the intersections between them and the spacecraft must have a range of excellent electrical, mechanical, thermal, and corrosion resistance properties. At present, molybdenum foil is mainly used in aerospace interconnect, but because spacecraft are often affected by high-altitude radiation, meteorites, ultra-high temperature, ultra-low temperature and other complex environmental factors during orbital flight, in order to enhance the conductive ability of molybdenum foil and improve its damage resistance in a wide range, molybdenum foil material must be surface treated, that is, coated with a layer of protective metal silver. However, the bonding force between the silver layer and the molybdenum foil as the substrate is very poor, and there is a problem of mismatch of thermal expansion coefficient, and the interface is easy to crack, so as to fail.
The surface treatment process can effectively remove the grease and oxide layer on the surface of molybdenum foil by adopting reasonable pretreatment steps. The high vacuum electron beam evaporation technology can effectively avoid the secondary oxidation of molybdenum foil, and can precisely control the coating thickness. The mechanical and thermal properties of the workpiece can be effectively improved by using the nickel-chromium alloy layer as the buffer layer. High vacuum annealing treatment of Nichrome alloy can effectively enhance the binding force with molybdenum foil; At the same time, the process is simple in operation and low in cost, which can meet the needs of mass processing of products.
