TRIBOTECHNICAL PROPERTIES OF COMBINED COATINGS WITH CARBON-CONTAINING FILLERSINTEGRATED TECHNOLOGIES

Abstract

From the variety of options for combining primary coating technologies, it follows that the most widespread coating technologies used in mechanical engineering, primarily gas-thermal spraying, are in greatest need of improving their properties. The main disadvantages of sprayed coatings are insufficient hardness and wear resistance. It is proposed to increase the tribotechnical properties of sprayed coatings by modifying them with carbon-containing fillers with their subsequent electrocontact treatment. Tribotechnical tests were conducted to study the features of structural and phase transformations in the friction surfaces of sprayed coatings in the presence of carbon-containing fillers. It was established that electrocontact treatment increases the wear resistance of sprayed coatings made of 40X13 steel both with and without carbon fillers. The increase in wear resistance of the coating with carbon-containing fillers is associated with both an increase in its microhardness and an increased content of residual austenite in the layer. In addition, the transformation of austenite into martensite also strengthens the surface layers and leads to the appearance of compressive stresses in them, which prevents fracture during friction. It is shown that as a result of the ECZ of the coating of steel 40X13, the intensity of wear of the layer is significantly reduced (by 3-4 times) and its friction coefficient increases slightly. Saturation of coatings with UDAG contributes to an increase in the wear resistance of coatings of steel 40X13 subjected to electrocontact treatment by 5 times, and reduces the friction coefficient of the tribocontact. During tribotechnical tests, it was determined that steel coatings made of 40X13 steel with diamond-containing filler have a fairly high wear resistance in the range of specific loads of 50 - 90 MPa: the wear intensity of these coatings was from 0.72 to 0.97 μm/km.