Incorporation of SiC on the mechanical properties, tribological performance, and oxidation resistance of HfC-SiC/a-C:H coatings prepared by hybrid HiPIMS and pulsed-DC magnetron co-sputtering

The multiphase nanocomposite HfC-SiC/a-C:H coatings consisting of HfC and SiC grains dispersed in the amorphous carbon matrix were deposited by hybrid HiPIMS and pulsed-DC magnetron co-sputtering. The incorporation of SiC ranging from 0 to 21.3 at.% on the chemical bonding state, nanocomposite structure, mechanical and tribological properties, and oxidation resistance of the coatings were explored. Results showed that the increase of SiC content is mainly at the expense of a-C:H matrix rather than nanocrystalline HfC, and is accompanied by changes in the HfC crystallinity. Nanohardness of up to 45 GPa was obtained for the HfC-SiC/aC:H coating with 6.6 at.% SiC content. The optimum wear rate of 6.4 x 10(-7) mm(3)/N and friction coefficient of 0.2 were also obtained at 6.6 at.% SiC content. The oxidation resistance is enhanced with the increase of SiC content, which delays the oxidation temperature by 100 C-degrees with respect to the HfC/a-C:H coating.