Керметные плазменные покрытия TiC – Cr3C2 – WC – NiCr – Mo – C

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Two bulk cermets TiC – WC – Cr3C2 – Ni 20 % Cr – Mo – 2.8% C after liquid-phase sintering at 1400 °C for 1 hour were used to manufacture powders for plasma spraying of coatings. Cermets were obtained with limited time of mechanical alloying at the stage of mixing. Plasma coatings were sprayed on a setup with a nozzle attached to a plasmatron for local protection of the sprayed particles from the air atmosphere. The content of WC – Cr3C2 – C in the cermets provided compensation for carbon losses at all stages of coating production and the formation of an annular zone, the volume of which determines the increase in the TiC content in the coatings by 20 % and the formation of additional carbides in the matrix. The microhardness of cermet with an initial carbide content of 60% is 15.26 – 16.83 GPa with a load on the indenter of 200 G and 20.91 – 24.68 GPa with a load on the indenter of 20 G, the difference was explained by a scale factor. The contribution of the microhardness of carbides to the microhardness of cermet with an initial carbide content of 60% was estimated according to the rule of mixtures, proceeding from their volume fraction and microhardness of cermet under a load on the indenter of 20 G. In the initial powder for spraying, this contribution is high, 33.19 GPa, close to Hardness TiC. The contribution of microhardness of carbides in the coating is lower, 28.09 GPa.