Tribological behaviors of a Ni-free Ti-based bulk metallic glass in air and a simulated physiological environment

Ni-free Ti-based bulk metallic glasses (BMGs) with good mechanical properties, high corrosion resistance, and good biocompatibility are potential biomaterials. For the applications as load-bearing orthopedic implant materials, excellent wear resistance is required. In the present study, tribological behaviors of the Ni-free Ti₄₇Cu₃₈Zr_7.5Fe_2.5Sn₂Si₁Ag₂ BMG in air and a phosphate buffer saline (PBS) solution were investigated and compared with Ti−6Al−4V and Co−28Cr−6Mo alloys. It was found that the wear resistance of the Ti-based BMG in air was superior to that of the Ti−6Al−4V alloy and paralleled with that of the Co−28Cr−6Mo alloy, mainly attributing to the high hardness of the Ti-based BMG. Under the dry-sliding condition, the predominant wear mechanism of the Ti-based BMG was characterized as the oxidation and abrasive wear. Under the PBS-solution condition, although the Ti-based BMG suffered from tribocorrosion that is controlled by the combined effects of abrasive and corrosive wear, the wear resistance of the Ti-based BMG was three times lower than that of the Ti−6Al−4V alloy and slightly inferior to that of the Co−28Cr−6Mo alloy. The effect of corrosion behavior on wear resistance of the Ti-based BMG in the PBS solution is discussed.