Study of the composition and of the mechanical properties of TiBN films obtained by dc magnetron sputtering

The growth of Ti-B-N films obtained by d.c. magnetron cathodic sputtering is studied. The wide influence of process parameters such as nitrogen flow rate, bias voltage and growth temperature on composition and on mechanical properties such as hardness, wear resistance, adhesion and intrinsic stress is pointed out, When nitrogen is introduced (even at a low flow rate) the films appear to be amorphous by XRD analysis. The XPS analysis shows the presence of Ti-B, Ti-N and B-N bondings whose proportions depend on the nitrogen flow rate. The mechanical properties are a function of the relative amounts of these bondings. The highest microhardness (approximately 40 GPa) is obtained when the proportions of Ti-B, Ti-N and B-N bondings are comparable. This high hardness value leads to a good wear resistance which is associated to a low compressive stress level (between -1 and -2 GPa).