Aging Tests of the High Current Aluminum–Copper Contact Connections in the ITER DC Busbar System

In ITER, the superconducting coils will be connected with ac/dc converters by water-cooled aluminum busbars, whose segments will be interconnected by copper flexible inserts to compensate for cyclic thermal expansion. This paper presents the experimental data obtained during development and testing of high-current aluminum-copper contact connections with various coatings protecting against corrosion and oxidation including multilayer and composite coatings, coatings with an additional interlayer. With the testing results, the coating method has been chosen for the protection of the contact surfaces of aluminum busbars and flexible copper inserts, which will be used during manufacturing of the busbars for the power supply system of the ITER magnet system coils.