Deposition of TiAlN coatings by RF sputtering technique

The role of coatings as a surface modification technique has grown significantly for applications in automobile, aerospace, electronic, biomedical, cutting tool industries etc. since they can impart specific properties such as hardness, toughness, wear resistance, etc. to a surface. Transition metal nitride coatings have been widely used as protective hard coatings to increase the lifetime of cutting and forming tools. The use of hard coatings has spread well beyond tools; they are now being used for many tribological applications and also for decorative purposes. Among the significant developments in the area of hard coatings has been the synthesis of nanostructured coatings like nanoscale multilayers and nanocomposites. Highly sophisticated surface related properties like mechanical, optical, magnetic, electronic and tribological properties can be obtained using nanostructured coatings. Nanocomposite coatings of transition metal nitrides are the emerging class of superhard materials and apart from high hardness they also exhibit high oxidation resistance, toughness, corrosion and wear resistance and even retain their high hardness at elevated temperatures. In this report salient results pertaining to the development of various superhard nanocomposite coatings are presented with an emphasis on TiAlN and TiAlN-Si3N4 nanocomposites. Important results related to the superhard nanocomposite coatings are presented. Finally, the potential applications of the superhard nanocomposite coatings are also presented