Structural-Phase State and Hardness of Composite Cu–Al Coatings Obtained by High-Speed Metallization Method

The aim of the work was to study the structure, phase composition, and hardness of composite gas-thermal coatings of the Cu–Al system, sprayed by hypersonic metallization using industrial wire materials from welding bronze CuSi3Mn1 and aluminum alloy AlSi12. It is shown that interdiffusion occurs between the bronze and aluminum interlayers during the sprayed of coatings and the intermetallic compounds Cu9Al4, CuAl2, and Cu3Al are formed. The porosity of the sprayed coatings did not exceed ≈10 vol %. The hardness of the composite coatings was 180–190 HV 1, and their microhardness was 180–240 HV 0.025. It has been established that annealing coatings of the Cu–Al system at 175 and 225°С for 2 h leads to an increase in the content of intermetallic compounds in them as well as an increase in their microhardness to 260 HV 0.025. It is concluded that the composite coatings of the Cu–Al system, obtained by the method of hypersonic metallization, can be used as an antifriction material for friction pairs.