Tribocorrosion Behaviour of a Ti–25Nb–3Zr–2Sn–3Mo Alloys Induction Nitride Layer in a Simulated Body Fluid Solution

Ti–25Nb–3Zr–2Sn–3Mo (TLM) alloys have been used in orthopaedics due to their excellent biocompatibility. However, the poor tribological performance caused by the low shear strength limits the applicability of TLM alloy. Herein, the surface of the TLM alloy was strengthened by induction nitriding technology, and the microstructure of the formed nitride layer as well as its corrosion property were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical workstation. The results showed that a gradient nitride layer with a thickness of ~30 μm was obtained on the surface of the TLM alloy after induction nitriding and the surface microhardness of the TLM alloy also increased from approximately 230 HV to 1253 HV. Meanwhile, the corrosion resistance of the TLM alloy in simulated body fluids (SBFs), was significantly improved by the nitride layer, which was supported by the corrosion potential value increasing from −665.77 (the raw sample) to −241.00 mV (the nitrided sample). Triborrosion behaviour is also characterized by a reciprocating sliding wear tester connected to an electrochemical workstation with different electrochemical conditions. The results evidenced that the TLM alloy has excellent tribocorrosion resistance after induction nitriding, who’s the mechanical material loss (WA) was only 0.23% of that of the raw sample under a 10 N load, and the total material loss (WT) was 15% of that of the raw sample.