Improving the mechanical and tribological properties of amorphous carbon-based films by an a-C/Zr/ZrN multilayered interlayer

Abstract

Amorphous carbon (a-C) films have been widely investigated to reduce the wear of medical implants due to their excellent tribological performance; however, the high internal stress of a-C films generated during the fabrication process remains an important scientific problem. Herein, we report novel a-C-based films with an a-C/Zr/ZrN multilayered interlayer. Our results reveal that, with increasing thickness of the multilayered interlayer, the hardness of the films decreased while their toughness and adhesion were improved. The Zr layers could act as a ductile phase, providing a toughening effect. A film with a 2:1 thickness ratio of multilayered interlayer to a-C top layer exhibited favorable tribological properties at various applied loads, especially at high applied load. The results indicated that by introducing a multilayered interlayer into a-C based films, the toughness and adhesion could be significantly improved without adversely sacrificing hardness. The tribological properties could be optimized by carefully tailoring the thickness ratio of multilayered interlayer to a-C top layer.