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The effects of nitrogen incorporation into amorphous boron carbide (B 4 C) films were studied. The films were deposited by dc-magnetron sputtering with the Si substrates at room temperature. The nitrogen incorporation occurs at the expense of the boron content. The main feature of infrared absorption spectra obtained from B 4 C films is a broad band at around 1100 cm --1 that shifts to higher wavenumbers upon nitrogen incorporation. The spectra obtained from films with higher nitrogen content are typical of hexagonal boron nitride. The friction coefficient and the surface wear were studied by lateral force microscopy. The influence of several parameters like relative humidity, scanning velocity and load force was investigated. For boron-carbon nitride films, a weak dependence on the relative humidity of wear and friction coefficients was observed. In the case of B 4 C films, there is a clear correlation between the wear depth and the energy deposited at the AFM tip-film interface.

The analysis of friction and wear of boron carbide films scanned with a light load atomic force microscope Si3N4 tip is presented. The results show that nano-scale friction and wear are strongly correlated, and that friction decreases fast at the beginning of the scratching tests. We propose that the energy dissipated at the tip-surface interface during scanning induces the formation of a lubricant material at the surface of the boron carbide film that reduces friction.

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The investigation of the modifications of the nanoscale tribological properties of boron carbide films induced by the energy dissipation at the interface between the atomic force microscope tip and the film surface is presented. It is shown that the microscope tip induces a modification at the surface that results in a decrease on the friction forces between the tip and the film surface. The influences of the friction coefficient, the scanning speed, and the applied normal force on the film wear are investigated. Using a microscopic model, the dissipated energy at the tip–surface interface during scanning was estimated. The influence of the dissipated energy on the nanoscale wear is presented and a strong correlation between friction and wear, in nanoscale, is shown.