Tribological properties of graded diamond-like carbon films on Ti ion-implanted aluminum substrate

Titanium ions are implanted into the aluminum substrate prior to deposition of the Ti interlayer and DLC graded film produced by magnetron sputtering in order to enhance the structural continuity between the soft substrate and graded DLC film. The Ti-implanted substrate not only strengthens loading support but also improves adhesion with the overlying film. The total thickness of the functionally graded film on the Al substrate reaches over 10 μm and it has a hardness value of ~ 11 GPa. The graphitic network in DLC film helps to reduce the friction coefficient while the graded design disperses the stress during wear and loading.