Tribo-functional PVD thin films deposited onto additively manufactured Ti6Al7Nb for biomedical applications

Abstract

For biomedical applications, the additive manufacturing of titanium-based alloys in combination with a subsequent physical vapor deposition (PVD) of tribo-functional thin films enables producing complex-shaped implants and devices with improved tribological behavior. Titanium nitride (TiN), titanium carbonitride (TiCN), amorphous carbon (a-C), and Ag-containing amorphous carbon (a–C:Ag) thin films were coated on laser powder bed fused (L-PBF) Ti6Al7Nb substrates by magnetron sputtering. TiN exhibits a high adhesion on Ti6Al7Nb, whereas TiCN, a–C, and a–C:Ag have a lower adhesion strength. In lubricated tribometer tests against Al2O3, the PVD thin films are highly effective in improving the tribological properties of additively manufactured Ti6Al7Nb. TiCN, a–C, and a–C:Ag show lower friction than uncoated Ti6Al7Nb and TiN, with a–C and a–C:Ag having the lowest coefficients of friction. Compared to uncoated Ti6Al7Nb, the PVD films also considerably reduce both the wear and counterpart wear.