Study on cyanide-free silver plating of interlinked molybdenum foils in spacecraft solar arrays
Molybdenum and molybdenum combined metal high temperature resistant materials, can maintain high strength at high temperature, but also has high thermal conductivity and low coefficient of thermal expansion, good thermal impact and electrical conductivity and wear resistance, is widely used in aerospace, including for spacecraft solar arrays interlinked molybdenum foil. But molybdenum weldability is relatively poor, and the high temperature will be strong oxidation, this oxide film has no protective effect, so it needs to be modified by electroplating on the surface of molybdenum foil. Because silver has good brazing properties, silver is usually electroplated on molybdenum foils to improve weldability and reduce or prevent molybdenum oxidation. However, natural oxide (MoO3) is often present on the surface of molybdenum foil, which will interfere with the adsorption of the coating, and it is difficult to form alloy (solid solution) between molybdenum and silver. Therefore, it is difficult to electroplate silver on the surface of molybdenum foil, and the direct silver plating is often not adhere to fast, and the coating quality is poor. The WAY TO solve the difficulties of molybdenum electroplating is usually to use pre-plating or impact plating on the surface of a thin layer of metal (such as chromium, nickel, gold, rhodium, platinum, etc.), after high temperature heat treatment and then continue plating, the process is more complicated.
If the metal plasma injection modification technology is used to directly inject Ag ions into molybdenum, the Ag modified layer with no obvious interface and high binding strength can be obtained, and the natural oxide can be removed by ion beam bombardment and the surface conductivity can be improved. On the basis of the electroplating of molybdenum foil, Ag electroplating with good quality and high binding strength can be obtained.