The effect of deep-case oxygen hardening on the tribological behaviour of a-C:H DLC coatings on Ti6Al4V alloy

A new duplex surface treatment combining the boost diffusion oxidation (BDO) treatment with amorphous hydrogenated diamond-like carbon hard coatings (BDO/a-C:H DLC) has been developed. Experiments results demonstrated that the BDO pre-treatment can effectively improve the scratch resistance and load bearing capacity of a-C:H DLC on Ti6Al4V. This is mainly because the hardened case in Ti6Al4V conferred by the BDO treatment can provide adequate mechanical support for the thin hard top carbon coating.