ABSTRACT
An idea to improve mechanical and functional properties of the transition metal nitrides by the addition of silicon into the films has arisen from previous studies dealing namely with the addition of boron [1-4]. The refinement effect of boron through the formed boron nitride amorphous matrix, hindering the grain growth and forming a nanocomposite structure, results in reaching superhardness in Ti-B-N films [5,6]. Such effect of structure refinement and thus enhancement of the functional film properties through the nanocomposite nature of the films preventing the dislocation movement may be obtained by the addition of several alloying elements. However, it does not always lead to the improvement of the thermal stability and oxidation resistance of the films. Especially at high working temperatures close to 900°C, the loss of the enhanced mechanical properties has often been observed [7]. Another disadvantage of these hard and superhard nanocomposites is the high stress level generated during the film growth. It may cause troubles while the coated tools are subjected to high loads in cutting applications. The adhesion problems and film delamination under applied mechanical loads mainly restrict the use of coated tools in practical applications. For that reason, a great interest has been devoted to find other alternative alloying element which might overcome the observed limitations and extend the usage of the transition nitrides into other branches of industry.
