Development of Technological Recommendations for the Formation of Composite Oxide Powder for Plasma Spraying

The article considers the conducted research on the formation of composite powder for plasma spraying. The development of new compositions based on known ceramic powder materials is associated with increasing requirements for improving the properties of plasma wear-resistant coatings, since only powder composites can simultaneously contain compounds of elements with different physical and chemical compositions, allowing to improve the properties of plasma coatings formed on their basis. In technologies for creating plasma coatings based on nickel, for further improvement of operational properties of these systems, carbon and boron are introduced into these systems, promoting the formation of carbide and boride phases, increasing fracture toughness, creep time, and the period of long-term strength. These phases are more thermally stable in comparison with γ-phases and, moreover, at temperatures exceeding the solubility limits, highly dispersed γ´-precipitates increase the strength characteristics of heat-resistant nickel alloys. Strengthening with carbide inclusions is especially significant at operating temperatures exceeding 1500 K, when the quantitative indices of the γ-phase in alloys decrease significantly. In previous studies, B4C powder was applied as separate coatings or used as a reinforcement in composite ceramic coatings, which showed improved mechanical and thermodynamic properties. The presence of B4C in various composite coatings made from B4C – NiCrAlY – Al2O3, B4C – Al – W, Al – B4C and B4C – Ni powders improved microhardness, corrosion resistance, and the strength characteristics of the carbide-metal interface, and also increased wear resistance. Composite materials based on metal-chromium-aluminum-yttrium (M-rolay) systems strengthened by non-metallic phases have been developed. Based on the conducted studies of the influence of the ratio of the number of components in the powder composite, granulation and spheroidization modes on the kinetics of the formation of the composite material, the optimal composition of the Al2O3 – TiO2 – В4С (Ni) – Ni – Cr – Al – Y – Ta powder was developed, while maintaining its strength characteristics, its physical, mechanical and tribological properties have increased compared to analogues: hardness has increased by 1.2 times, wear intensity has increased by 1.3 times under lubrication friction and by 1.4 times under dry friction. Thus, the proposed method for producing a composite material allows to increase the wear resistance of coatings under hightemperature corrosion conditions.