Amorphous SiC PVD coatings

Abstract Silicon carbide belongs to the ultrahard materials as well as diamond and diamond-like coatings. These materials are interesting because of their properties such as low friction coefficient, wear resistance and hardness. In comparison with diamond and diamond-like coatings SiC shows better thermal stability. The deposition of silicon carbide is easily achieved by magnetron sputter ion plating (MSIP) using an SiC target in a d.c. process. This method affords a high deposition rate and high reproducibility. These coatings are normally deposited with an X-ray-amorphous structure. This structure shows better properties than comparable coatings. At temperatures around 800°C these thin films begin to crystallize. This process is accompanied by crack formation, which is close to coating failure. Coating peeling is not observed. A remarkable deterioration of coating properties such as hardness and adhesion is seen. This paper describes the stabilization of deposited amorphous SiC by variation of technical parameters such as process temperature and bias. The variation of some additional elements for structure stabilization is also carried out. A way to improve the coating adhesion on cemented carbide by using the multilayer technique with base layers such as TiC and TiN is described.