OPERATIONAL PROPERTIES OF CONSTRUCTION MATERIALS WITH PROTECTIVE COATINGS OBTAINED UNDER NON-STATIONARY TEMPERATURE CONDITIONS

Abstract

The structure and phase composition of chromium-alloy coatings consisting of the following phases are investigated in the work: when boron doping the coating on brass C68700 consists of phases: Cu₃Al, CuB, CuZn₂ and zones of solid solution Cr, Al, B in copper; during titanium doping Cu₃Al and CuAl phases in the transition zone: phases CuTi and CuTi₂ When tested on A572 steels, in conditions of sliding friction, the best wear resistance among the considered protective coatings are doped with titanium and boron. Their wear resistance is 1,8 – 2,1 times higher than that of coatings obtained under isothermal conditions. Under non-stationary temperature conditions, the microhardness reaches the following values: when doped with boron H₁₀₀ = 16500 – 17500 MPa, when doped with silicon H₁₀₀ = 13500 – 14500 MPa, when doped with titanium H₁₀₀ = 15000 – 16000 MPa. The obtained results correlate with the indicators of wear resistance. A comparative analysis of the corrosion resistance of protective coatings obtained under non-stationary temperature conditions and isothermal conditions shows that they have a weight loss of 1.7–2.1 times less. It was found that when tested in a 30% aqueous solution of sulfuric acid, all protective coatings have good stability. Thus, when doped with boron, the weight loss is 15,2 g/m², при when doped with silicon - 10,8 g/m²,  and when doped with titanium - – 9,9 g/m².