Carburized titanium as a solid lubricant on hip implants: Corrosion, tribocorrosion and biocompatibility aspects

As a well-known biomaterial, one disadvantage of the Ti6Al4V alloy is its tribocorrosion behavior, for which carbonate carburization has been introduced to make an improvement. In previous research, carbonate carburization method was applied on cp-Ti and the carburized specimens performed better in tribology tests. Based on their study, we applied the same methodology on Ti6Al4V; then, the carburized samples were characterized by scanning electronic microscopy (SEM), X-ray diffraction and Raman spectroscopy. Furthermore, the carburized samples were evaluated by corrosion, tribocorrosion and biocompatibility tests for whether the carbonate carburization provides any benefit. According to results from material characterization, carburization reduces the resistance of the alloy to corrosion in static conditions, but improves its resistance to erosion and tribocorrosion. The patchy oxycarbide layer elucidated the worse corrosion properties after carburization. Nonetheless, the formed oxycarbide showed less agitated corrosion, less wear debris and less friction coefficient in tribocorrosion experiments. Finally, cell proliferation and confocal images of cell-grown surface exhibited no obvious difference between the reference and carburized specimens. In conclusion, further research may help us modify the carburization process to prevent the sacrifice of corrosion resistance; moreover, better tribocorrosion resistance and good biocompatibility still present its potential in arthroplasty application.