Lawrence Berkeley National Laboratory

Hyper-thermal species have been used to produce carbon-based films with mechanical and tribological properties that have greatly expanded the applications of amorphous carbon coatings. Tetragonally bonded amorphous carbon films have properties that approach that of diamond in several ways. The major drawback, namely intrinsic stresses, preventing the production of thick ta-C films has been overcome by heat treating these films, and presently several micrometer-thick films of ta-C are regularly produced. Yet another area where superhard coatings are of great interest is for wear applications at elevated temperatures, namely around 500 degrees C and above. Such temperatures may be environment temperatures, or localized (flash) temperatures resulting for instance from wear. For this applications, doping the ta-C with elements that are covalently bonded to C (such as Si and B) offers a promising alternative. In this article, I will discuss some treatments that have allowed expanding the applications of pure ta-C, and the incorporation of Si and B on ta-C films. Film properties are presented and discussed.