Different techniques, like PVD, CVD, ion implantation, are increasingly used to produce thin film layers of ceramic compounds to modify the surface properties of metals, carbides, ceramics or polymeric components for specialized conditions or in severe conditions of use. Carbides, nitrides, oxides, etc. have been deposited on the most varied supports to solve problems of high temperature, erosion, corrosion, diffusion and conductivity or electrical resistance. The fields of thin hard coating applications are: tools, dies, punches, mechanical components (for antiwear deposits), structures (for anticorrosion), optics (reflecting or absorbing layers) and microelectronics. In this paper we will present the principal characteristics of different thin hard coating layers and processes, and the principal applications in the anti-wear field.