ВОССТАНОВЛЕНИЕ ИЗНОШЕННЫХ ПОВЕРХНОСТЕЙ ТРЕНИЯ СКОЛЬЖЕНИЯ ГАЗОДИНАМИЧЕСКИМ НАПЫЛЕНИЕМ МЕДНО-ЦИНКОВЫХ ПОКРЫТИЙ

Abstract

Preliminary studies of copper and copper-zinc coatings obtained by gas-dynamic spraying have shown high mechanical and tribological properties of the formed functional surfaces. The influence of the modes of spraying and subsequent heat treatment on copper-zinc gas dynamic coatings has been little studied. (Research purpose) The research purpose is investigating the effect of technological modes of spraying, as well as subsequent heat treatment of the coating on its phase composition, structure and properties. (Materials and methods) The coating was applied using a Dimet gas dynamic installation with different overlap of the sprayed layers and subsequent heat treatment of the resulting coating at different temperatures and exposure times. The structure of the coating was studied using an X-ray diffractometer and a spectrometer. Cohesive properties were determined on a bursting testing machine by the "ring separation" method, tribological properties were determined on the MT-8 stand during reciprocating sliding of flat mating bodies. (Results and discussion) It was determined that the chemical and phase composition of the copper-zinc coating applied with a displacement of the nozzle by two millimeters and an air flow temperature of 450 degrees Celsius, after heat treatment in the temperature range of 420-430 degrees Celsius and a holding time of 180 minutes corresponds to two-phase brass type L65. The study of the parameters of the copper lattice shows that after exposure in the furnace for 60 minutes, a two-phase structure is formed based on solid solutions of zinc in copper with different copper content and an electronic-type solid solution based on CuZn. (Conclusions) Tribological tests of the copper-zinc coating in the I-20A industrial oil medium revealed the presence of mutual mass transfer of copper and zinc from the coating to the counterbody and vice versa, which is accompanied by a wear-free effect at a load of up to 10 megapascals. The cohesive strength of the copper-zinc coating depends on the time of heat treatment (phase composition) and after 60 minutes of exposure exceeds the initial values (approximately 78 megapascals) and reaches approximately 93 megapascals.