Thermal stability of nc-TiN/a-BN/a-TiB2 nanocomposite coatings deposited by plasma chemical vapor deposition

Abstract Thermal stability of nc-TiN/a-BN/a-TiB 2 nanocomposites prepared by plasma chemical vapor deposition at a total pressure of several mbar and deposition temperature of 570 °C with TiCl 4 , BCl 3 , N 2 and H 2 as reactants was investigated. It was shown that the thermal stability of nc-TiN/a-BN/a-TiB 2 nanocomposite coatings is fairly high but lower than that of the nc-TiN/a-Si 3 N 4 and nc-TiN/a-Si 3 N 4 /a-TiSi 2 coatings. The loss of boron from the coating together with the diffusion of chromium and other elements from the steel substrate into the coating during annealing are limiting the thermal stability of these coatings.