チタンのプラズマ浸炭窒化による硬質Ti(C,N)層の作製

抄録

Plasma carbonitriding process has been applied to preparation of hard Ti(C, N) layer on the surface of titanium plate at relatively low temperatures. The formation of thick Ti(C, N) layer was confirmed by means of XRD and ESCA measurements and Vickers hardness test. The carbonitriding was carried out in an r.f. (4 MHz) glow plasma generated in quartz tube using N₂–C₂H₂ gas mixtures. The Ti(C, N) layer consisted of continuous solid solution of TiN and TiC. With increase in the C₂H₂ ratio of carbonitriding gas, the thickness of carbonitriding layer somewhat decreased, but the friction coefficient of the surface was improved and its value was similar with that of commercial TiN films for cutting tools. The addition of inert gas (He, Ar) into N₂–C₂H₂ gas somewhat decreased the thickness of the carbonitriding layer, while the surface roughness of carbonitrided Ti was rather improved. It may be presumed that the bombardment of massive inert gas ion assists to make the surface more smooth.