Structural, chemical, optical and mechanical properties of Au doped AlN sputtered coatings

This paper is focused on the structure, chemical composition, optical and mechanical properties of coatings consisting in an AlN matrix incorporating different Au contents (up to 2.5 at.%). The Au was incorporated in the matrix atomically or in the form of very small nanoparticles (< 1 nm). With the increase in the Au content both the refractive index and the coefficient of extinction were increased. The AlN matrix presented a crystalline wurtzite phase, stable up to 1000 °C. nnealing at 400 °C the precipitation of XRD detectable Au nanoparticles was possible, originating SPR light absorption. The AlN + Au coatings exhibited hardness values between 15 and 24 GPa, with no significant changes after the annealing treatments at low temperatures. These coatings are of interest to the decorative applications.