Friction and wear study of diamond-like carbon gradient coatings on Ti6Al4V substrate prepared by plasma source ion implant-ion beam enhanced deposition

DLC gradient coatings had been deposited on Ti6Al4Valloy substrate by plasma source ion implantation-ion beam enhanced deposition method and their friction and wear behavior sliding against ultra high molecular weight polyethylene counterpart were investigated. The results showed that DLC gradient coated Ti6Al4V had low friction coefficient, which reduced 24, 14 and 10% compared with non-coated Ti6Al4V alloy under dry sliding, lubrication of bovine serum and 0.9% NaCl solution, respectively. DLC gradient coated Ti6Al4V showed significantly improved wear resistance, the wear rate was about half of noncoated Ti6Al4V alloy. The wear of ultra high molecular weight polyethylene counterpart was also reduced. High adhesion to Ti6Al4V substrate of DLC gradient coatings and surface structure played important roles in improved tribological performance, serious oxidative wear was eliminated when DLC gradient coating was applied to the Ti6Al4V alloy