Abstract
Ion-plasma spraying and co-precipitation of ultrafine Ta and Cd particles, as well as W and Cd doped with Nb and Mo, for the first time produced coatings represented by a mixture of crystallized cadmium and amorphous refractory metals. Vacuum annealing at 800 ° C for 1 hour completely evaporated cadmium from the coatings to obtain cellular structures, the degree of blackness of which depends on the doping of Nb and Mo. The blackest coatings were obtained from porous tantalum doped with niobium and porous tungsten doped with niobium and molybdenum. The resulting black coatings have sufficient electrical resistance.