Improving durability of titanium for biomedical use by composite ceramic coatings

Abstract

New composite ZrO2/SiO2 coatings on grade 4 titanium have been produced by the sol-gel synthesis and dip coating, in order to improve durability of the substrate. Mechanical testing by scratch test and nanoindentation allowed to identify the coatings with better adhesion, lower tendency to crack, stiffer, harder and with lower friction against diamond in dry sliding. Potentiodynamic polarization tests in Dulbecco’s phosphate-buffered saline solution were used to evaluate a possible extra corrosion protection imparted by the coatings to the already excellent corrosion resistance of the passivated grade 4 titanium substrate. The silica-containing coatings appeared to be the best tradeoff between the improvement of mechanical and corrosion resistance properties.New composite ZrO2/SiO2 coatings on grade 4 titanium have been produced by the sol-gel synthesis and dip coating, in order to improve durability of the substrate. Mechanical testing by scratch test and nanoindentation allowed to identify the coatings with better adhesion, lower tendency to crack, stiffer, harder and with lower friction against diamond in dry sliding. Potentiodynamic polarization tests in Dulbecco’s phosphate-buffered saline solution were used to evaluate a possible extra corrosion protection imparted by the coatings to the already excellent corrosion resistance of the passivated grade 4 titanium substrate. The silica-containing coatings appeared to be the best tradeoff between the improvement of mechanical and corrosion resistance properties.