The advantages of using Nb and Ti-Nb coatings for improving the hardness and corrosion resistance of Ti6Al4V were investigated. It has been reported that Ti6Al4V used in orthopaedic implants tends to release toxic Al and V ions into the surrounding tissue. Thin layers of Nb and Ti-Nb were deposited on Ti6Al4V substrates using a laser metal deposition technique. The deposited material was analysed using optical microscopy, scanning electron microscopy coupled with energy dispersive spectroscopy, and X-ray diffraction. The corrosion behaviour of the deposited layers was investigated using a Metrohm Autolab PG Stat101 compact potentiostat at 25°C in simulated body fluid. A Vickers hardness system was used to study the mechanical properties. Both Nb and Ti-Nb coatings exhibited good metallurgical bonding with the substrate. The microstructure and the XRD analyses for the Nb system showed that the a-Nb phase was most dominant, while the Ti-Nb system comprised a mixture of the a and b phases. The average hardness of the Ti6Al4V substrate was 350 HV(sub0.3), with a slight increase for the Nb coating (363 HV(sub0.3)) and a much higher hardness from the Ti-Nb coating at 423 HV(sub0.3). The corrosion results show that the deposited Nb was more corrosion-resistant in the solution than either the Ti6Al4V substrate or the Ti-Nb coating.
Reference:
Pityana, S.L., Baloyi, N., Tlotleng, M. & Popoola, P. 2019. Laser surface deposition of niobium and titanium-niobium on Ti6A14V substrates for biomedical applications. Journal of the Southern African Institute of Mining and Metallurgy, vol 119(4), pp. 385-389
Pityana, S. L., Baloyi, N., Tlotleng, M., & Popoola, P. (2019). Laser surface deposition of niobium and titanium-niobium on Ti6A14V substrates for biomedical applications. http://hdl.handle.net/10204/11263
Pityana, Sisa L, N Baloyi, Monnamme Tlotleng, and P Popoola "Laser surface deposition of niobium and titanium-niobium on Ti6A14V substrates for biomedical applications." (2019) http://hdl.handle.net/10204/11263
Pityana SL, Baloyi N, Tlotleng M, Popoola P. Laser surface deposition of niobium and titanium-niobium on Ti6A14V substrates for biomedical applications. 2019; http://hdl.handle.net/10204/11263.