Tribocorrosion response of different multilayer TaN coatings in biological environments

摘要

The principal cause of failure of biomedical implants is due to the tribological processes (friction and wear) they are exposed to during their lifetime. Besides, these processes are found to accelerate the corrosion mechanisms occurring in the aggressive environment the body represents. The first contacting area is the surface; therefore, the problem can be minimized by the development and application of adequate coatings combining both low friction and high corrosion and wear resistance. Tantalum nitride (TaN) is a hard, chemically inert, highly corrosion resistant biocompatible material. These features make it an excellent candidate for application as protective coating on biological corrosive environments. Recently developed high power pulsed magnetron sputtering (HPPMS) is a physical vapor deposition technology able to create columnar-free, fully dense and less defective TaNx coatings. In the present work, multilayer TaN coatings characterized by different bilayer periods have been deposited on titanium biomedical alloys. Corrosion, wear and tribocorrosion performance has been analyzed in simulated body fluids with protein content. TaN films strongly decreases wear rates of titanium substrates when they are simultaneously submitted to electrochemical and tribological effects, being a very attractive candidates for their use in biomedical field.