LAUSR

Abstract A novel wear and corrosion resistant β-Ta 5 Si 3 coating was deposited onto a Ti-6Al-4V substrate using a double glow discharge plasma method. The structure of the coating was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), and its mechanical properties were determined by a combination of nanoindentation and scratch testing. Dry sliding wear behavior of the β-Ta 5 Si 3 coating was evaluated using a ball-on-disc tribometer. Further, the electrochemical behavior of the β-Ta 5 Si 3 coating was assessed through immersion in a 3.5 wt% NaCl solution. The as-deposited coating consisted of equiaxed tetragonal D8 m -structured Ta 5 Si 3 exhibiting a ∼4 nm grain size with a pronounced (400) preferred orientation. The specific wear rates of the β-Ta 5 Si 3 coating were ∼10 −6 mm 3 /(N m), which is two orders of magnitude better than that of the uncoated substrate under the same test conditions. This is because the coating exhibits higher values of H/E. Finally, the corrosion resistance of the coating was improved relative to bare alloy in this solution. Mott-Schottky analysis showed that the passive film formed on the coating during corrosion testing behaved like an n-type semiconductor. The carrier density was one order of magnitude less than that formed on bare substrate in the same solution. In light of this, the β-Ta 5 Si 3 nanocrystalline coating is expected to provide protection to metallic components against wear and corrosion and as such extend their service life.