Self-lubricating Ti–C–N nanocomposite coatings prepared by double magnetron sputtering

This paper is devoted to the development of Ti(C,N)-based nanocomposite protective coatings consisting of nanocrystals of a hard phase (TiN or TiCxNy) embedded in an amorphous carbon-based matrix (a-C or a-CNx). The objective here is the achievement of a good compromise between the mechanical and tribological properties by the appropriate control of the hard/soft phase ratio and the microstructural characteristics of the film. To achieve this purpose, dual magnetron sputtering technique was employed following two different strategies. In the first one, we use Ti and graphite targets and Ar/N2 gas mixtures, while in the second case, TiN and graphite targets are sputtered in an Ar atmosphere. By changing the sputtering power applied to each magnetron, different sets of samples are prepared for each route. The effect of the bias voltage applied to the substrate is also studied in some selected cases. The mechanical and tribological properties of the films are characterized and correlated with the microstructure, crystallinity and phase composition. The establishment of correlations enables the development of advanced coatings with tailored mechanical and tribological properties for desired applications.

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