Exceptional improvement in the wear resistance of biomedical ?-type titanium alloy with the use of a biocompatible multilayer Si/DLC nanocomposite coating

Abstract

A silicon/diamond-like carbon (Si/DLC) multilayer nanocomposite coating (MNC) was applied to the Ti-29Nb-13Ta-4.6Zr (TNTZ) alloy to improve its wear resistance and durability. The Si/DLC MNC on the TNTZ alloy demonstrated an extremely low wear rate of 6.2 x 10-10 mm3N- 1mm- 1. Moreover, the wear track depth after one million wear cycles was found to be only 220 nm, while the thickness of the entire coating was 370 nm. Furthermore, cell culture tests demonstrated that the Si/DLC MNC samples exhibited better biocompatibility than the TNTZ alloy samples. A quantitative comparison of the cell adhesion behavior of the TNTZ and Si/DLC MNC samples indicated that 60 of the surface of the Si/DLC MNC sample was covered with cells, which was approximately twice the surface of the TNTZ alloy sample covered with cells. In addition, no dead cells were observed on the Si/DLC MNC samples, indicating that the Si/DLC MNC samples exhibited no toxic effects against the MC3T3 cells. These results indicate that the Si/DLC MNC enhances the wear resistance of the TNTZ alloy and improves its biofunctionality, thus making it a potential candidate for use in long-term implant applications.