Bias-graded deposition and tribological properties of Ti-contained a-C gradient composite film on Ti6Al4V alloy

• Published in: Applied surface science 2013-08, Vol.279, p.450-457
• Main Authors: Cai, J.B., Wang, X.L., Bai, W.Q., Zhao, X.Y., Wang, T.Q., Tu, J.P.
• Format: Article
• Language: English
• Subjects: Amorphous carbon; Biocompatibility; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Exact sciences and technology; Friction; Gradient composite film; Mechanical property; Physics; Surgical implants; Titanium; Titanium base alloys; Tribological property; Tribology; Wear rate
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.04.136

•Bias-graded Ti-contained a-C composite film was deposited by magnetron sputtering.•The film has the hardness of 19GPa with high toughness and adhesion strength.•The bias-graded film showed excellent tribological property in ambient air.•Its good wear resistance in Hanks’ solution contributes to biological applications. Ti-contained a-C gradient composite film with a thickness 1.5μm was deposited on medical Ti6Al4V alloy substrate using a closed field unbalanced magnetron sputtering with bias-graded voltage through −20V to −150V. The mechanical and tribological properties were evaluated from nanoindentation, scratch test and ball-on-disk tribometer. Compared with the constant-bias film deposited at −150V, the bias-graded film has the approximate hardness (19GPa) but high toughness and adhesion strength. At a normal load of 10N, the bias-graded composite film shows a low friction coefficient of 0.08 and wear rate of 2.89×10−16m3N−1m−1 in ambient air. While in Hanks’ solution, the film has the same low friction coefficient but low wear rate of 4.63×10−17m3N−1m−1. Excellent wear resistance in Hanks’ solution may bring about a biological application for the Ti-contained a-C gradient composite film.