TiC/a-C:H nanocomposite coatings as substitute for MoS2-based solid lubrication in helium atmosphere

The existing challenges due to the extremely wear condition and variable serving environments require urgent improvements in the performance of solid lubrication coatings in helium atmosphere applications. In this paper, TiC/a-C:H and Ti–MoS2 coatings were deposited using magnetron sputtering process. The tribological performance of TiC/a-C:H and MoS2-based coatings were comparatively investigated under helium gas atmospheres. Results show that TiC/a-C:H coatings exhibit a super-low friction coefficient of around 0.02, and the wear rate of the TiC/a-C:H coatings was nearly one order of magnitude lower than Ti-MoS2 coatings. While the Ti–MoS2 coatings were characterized by severe adhesion wear and plastic deformation. The significant improvement in the tribological performance of TiC/a-C:H coatings can be attributed to the higher hardness and the large extent coverage of transferred carbon films on counterfaces. The good balance between hardness and toughness, super-low friction and excellent anti-wear properties of TiC/a-C:H coatings make them good substitution as solid lubricating coating for helium applications.