Influence of Ag nanoparticles on the mechanical and tribological properties and on the cytotoxic and bactericidal effects of TaN(Ag) coatings

In this work, a TaN(Ag) composite coating with different silver contents between 2.26 and 28.51 %at, were developed by the unbalanced magnetron sputtering technique. The coating with the best balance presented between tribological and mechanical properties was chosen, and it was subjected to thermal treatments cycles with temperatures among 175 °C and 275 °C to allow the nucleation, growth and controlled diffusion of Ag nanoparticles up to the coating surface; the size, distribution and density of nanoparticles on the coating surface and their influence on the mechanical and tribological properties, were verified. The bactericidal effect against P. aeruginosa by growth inhibition and adhesion test was studied, as well as the cytotoxic behavior on osteoblasts by MTT test. The TaN(Ag)-3 coating after thermal treatment at 200 °C during 4 min, increased the micro hardness of AISI 316L stainless steel from 2.6 GPa to 10.7GPa, and decreased the wear rate from 1.11x10-3 mm3/N.m to 0.17x10-12 mm3/N.m. This coating exhibited 100% of osteoblast cell viability, and an excellent performance to the inhibition of growth and adherence of P. aeruginosa