Features of the formation process of brass coating by gas-dynamic deposition of copper and zinc particles

Abstract

Coatings deposited on the surface of samples of steel 40X by the method of gas-dynamic deposition using the finished mechanical mixture of particles of copper, zinc and aluminum oxide. X-ray structural phase analysis reveals significant differences in the structure and phase composition of the coating applied when the nozzle is displaced by 2 mm and 3 mm. During gas-dynamic deposition of the coating using a mechanical mixture of copper, zinc and aluminum oxide (corundum) particles, in the deposited metal layer, copper, zinc, solid solution of copper in zinc (η-phase) and intermetallic (electronic) compounds are exposed based on CuZn3 (ε-phase) and Cu5Zn8 (γ-phase). Primary diffusion of copper to zinc is recorded; the diffusion coefficient has a high value of 0.75-2.25 x 10-8 cm2/s. The deformation of particles is accompanied by the formation of stresses, then their relaxation will take place due to the cooperative displacement of atoms, which will significantly increase the rate of diffusion of copper into zinc. In this case, a high value of the diffusion coefficient for gas-dynamic deposition of a coating based on copper and zinc particles should be attributed to a significant increase in point defects (vacancies) in zinc, as well as the onset and relaxation of deformation – stresses in copper particles. Analysis of the technological factors of deposition shows the effect of deformation on the diffusion of copper into zinc.