Improvement on biocompatibility and corrosion resistance of a Ti3Zr2Sn3Mo25Nb alloy through surface nanocrystallization and micro-arc oxidation

This paper reported a surface modification method to improve corrosion resistance and biocompatibility of a Ti3Zr2Sn3Mo25Nb alloy (named as TLM). A 100-μm-thick layer with an average grain size of 70 nm was created on the alloy surface through sliding friction treatment (SFT), followed by a micro-arc oxidation treatment (MAO) to create a porous coating. Phase composition, morphology, structural characteristics, and elemental characteristics of the MAO coating were inspected by scanning electron microscope (SEM), energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Corrosion resistance of the MAO coating was tested by electrochemical method, and the biocompatibility of the MAO coating was evaluated by cell adhesion and proliferation, and protein adsorption tests. It has found that the surface morphology and chemical composition of the MAO coating produced on the SFT surface (NG-MAO) were not significantly different from those of the MAO coating formed on the original TLM substrate without SFT (CG-MAO). However, the corrosion current density of the NG-MAO coating in 0.9% NaCl solution (PS) and simulated body fluid (SBF) solution decreased 43.4 and 46.7%, respectively, as compared to the CG-MAO coating. The polarization resistance of the NG-MAO coating was also 122% higher than that of the CG-MAO coating in PS. And the protein adsorption capacity and cell proliferation have been significantly increased on the NG-MAO coating compared to its counterpart, the CG-MAO coating. Graphical abstract