The Use of Electrochemical Methods to Determine the Effect of Nitrides of Alloying Elements on the Electrochemical Properties of Titanium β-Alloys

Titanium beta alloys represent the new generation of materials for the manufacturing of joint implants. Their Young's modulus is lower and thus closer to the bone tissue compared to commonly used alloys. The surface tribological properties of these materials should be improved by ion implantation. The influence of this surface treatment on corrosion behaviour is unknown. The surface of Ti-36Nb-6Ta, Ti-36Nb-4Zr, and Ti-39Nb titanium beta-alloys was modified using nitrogen ion implantation. X-ray photoelectron spectroscopy was used for surface analysis, which showed the presence of titanium, niobium, and tantalum nitrides in the treated samples and the elimination of less stable oxides. Electrochemical methods, electrochemical impedance spectra, polarisation resistance, and Mott-Schottky plot were measured in a physiological saline solution. The results of the measurements showed that ion implantation does not have a significant negative effect on the corrosion behaviour of the material. The best results of the alloys investigated were achieved by the Ti-36Nb-6Ta alloy. The combination of niobium and tantalum nitrides had a positive effect on the corrosion resistance of this alloy. After surface treatment, the polarization resistance of this alloy increased, 2.3 x 10(6) omega center dot cm(2), demonstrating higher corrosion resistance of the alloy. These results were also supported by the results of electrochemical impedance spectroscopy.

Automated summary

Titanium beta alloys have lower Young's modulus than commonly used alloys, making them more similar to bone tissue. Ion implantation can improve the tribological properties of these alloys, but its effect on corrosion behavior is uncertain. Surface analysis showed the presence of nitrides and the elimination of unstable oxides after nitrogen ion implantation. Electrochemical measurements demonstrated that ion implantation does not negatively impact the corrosion behavior of the material. The Ti-36Nb-6Ta alloy exhibited the best corrosion resistance, with the combination of niobium and tantalum nitrides contributing to its improved performance.