Hardening of the plasma spraying coating dispersed additional phase of titanium carbide

Abstract

Today in Russia, one of the most important stages in the development of additive gas-thermal technologies is the optimal choice of materials. In particular, in the field of gas-thermal methods for applying composite coatings on the surface of machine parts, plasma spraying technology is advanced and promising from the point of view of economic benefits and import substitution. In this paper, the issue of obtaining a composite coating with an additional dispersed phase (titanium carbide) is considered. The results of theoretical and practical studies on the peculiarities of hardening of the composite coating under study are presented. Calculations of shear stress according to the theories of Fischer-Hart-Pry and Orovan are presented. According to the current GOST, the shear strength of the coating under study is determined. As a result of the work, the structure of the composite coating from the sprayed material 76.5% PR-NX17CP4+23.5% TiC was investigated, namely: the structure of the sprayed composite coating in optical and scanning electron microscopy is presented. The transverse section of the composite coating is also analyzed, and conclusions are drawn on the nature of its formation. Defects of the applied layer of composite coating in the form of cracks, local delaminations, large pores were not detected. The microplate is characterized by high density, uniformity of structure, low porosity, absence of cracks and high adhesion strength of the coating to the substrate. Recommendations have been made on the possible use of plasma spraying material (76.5% PR-NH17CR4+23.5% TiC), in particular when restoring worn surfaces of aircraft landing gear racks and steering gear drives of military and civil aviation. These recommendations are justified due to the high shear strength values of the composite coating under study.