Processing and characterization of novel calcium titanate/Na-titanate nanotube/rutile nanocomposite coating on titanium metal

摘要

A novel nanocomposite coating, containing calcium titanate (CaTiO3), sodium titanate nanotube (Na-T) and rutile, was prepared on a titanium substrate. At first, calcium phosphate was deposited electrochemically on Ti substrate. Hydrothermal processing at 130 degrees C in 10M NaOH transformed calcium phosphate layer into well-crystallized calcium titanium oxide hydroxide (Kassite) and titanium surface into Na-T. Annealing at 350 degrees C transformed the titanium metal surface into rutile (TiO2) and the final coating was CaTiO3/Na-T/rutile composite. Hydrothermal treatment decreases adhesion bond strength and microhardness. Although the adhesion strength of the final coating was comparative to that of the initial coating, hardness and corrosion resistance were increased with annealing at 350 degrees C due to the formation of buffer layer of rutile phase.