Improve wear resistance of C/C composites as artificial bone using diamond-like carbon coatings

In this study, diamond-like carbon (DLC) coatings and silicon-doped diamond-like (Si-DLC) coatings were prepared on the surface of C/C composites by a combination of plasma-enhanced chemical vapor deposition (PECVD) and magnetron sputtering processes. The film composition, microstructure and atomic bond structure were characterized using X-ray photoelectron spectroscopy, field-emission scanning electron microscopy and Raman spectroscopy. The mechanical properties and friction behavior related to the Si element were investigated using nanoindentation and HT-1000 high temperature friction and wear tester. The biocompatibility of the materials was also evaluated by the MG-63 proliferation test. The results indicate that Si elements were successfully incorporated into the DLC films, bonding with C and O atoms, which altered the thermal stability and microstructure of the coatings, reduced the internal stress of the films, and increased disorder. Compared to C/C composites, all coated layers exhibited lower coefficients of friction, with the formation of transfer layers and graphitization induced by friction contributing to the excellent tribological performance. Both coatings showed no cytotoxicity and demonstrated good biocompatibility. Both coatings are effective in reducing wear and chip losses in C/C composites when used as artificial bones. This work suggests that diamond-like carbon coated C/C composites can be excellent structural materials for human body in biomedical science.