Abstract
Titanium aluminum nitride films were deposited on special dental alloys by reactive RF sputtering to modify the characteristics of nickel-based and chromium-based dental material. The surface hardness of the (Ti1-x,Alx)N films was measured by nanoindentation testing. The hardness of the films was enhanced by the introduction of aluminum as compared to pure TiN films. Nanoindentation tests showed that the surface hardness of the (Ti1-x,Alx)N was as high as 35GPa for a x value of 0.45. The sliding pin-on-disk was employed to investigate the wear resistance of the coatings as compared with dental alloys without any coatings. The friction coefficient of (Ti1-x,Alx)N films against cemented tungsten carbide was lower than that of uncoated dental alloys. To simulate the body environment, corrosion test was carried out in 0.9 wt. % NaCl solution. The morphology and microstructure of the coatings were analyzed by X-ray diffractometry and scanning electron microscopy. A lower corrosion current density was achieved for Ti0.75Al0.25N coated dental alloy as compared with uncoated dental alloys. In addition, the pitting corrosion was substantially reduced by the employment of TiAlN coating. The biocompatibility of three specimens was tested using a subcutaneous implantation test. Data were analyzed using the t-test with a significance level of p<0.05. Specimens coated with (Ti,Al)N films exhibited significantly improved corrosion resistance (p<0.05). The results from biocompatibility testing, based on tissue reactions at two and 12 weeks, revealed substantially enhanced biocompatibility for (Ti,Al)N coated samples when compared to uncoated samples. This demonstrates that the (Ti,Al)N film can significantly improve the electrochemical and biocompatibility properties of the base dental alloy.