High Si multilayered TiSiN/TiN(Ag) films with superior oxidation resistance

In this work, the effect of Ag content on the morphology, structure, mechanical properties, thermal stability, and oxidation resistance of multilayered TiSiN/TiN(Ag) films, with Si concentration in the range of 6.3-7.0 at.%, is investigated. The coatings are deposited by DC reactive magnetron sputtering, with increasing Ag content from 0 to 13.9 at.%. All coatings exhibit a face-centered cubic structure (f.c.c NaCl type) and the Ag diffraction peaks progressively increase with increasing Ag content. The hardness and the reduced elastic modulus of the as-deposited films decrease with increasing Ag; these mechanical properties are higher after annealing at 800 °C in protective atmosphere due to the improvement of the crystallinity of the films. The multilayered architecture of the coatings promotes a good barrier against Ag diffusion towards the surface in protective atmosphere. Ag addition does not influence the onset point of oxidation of the films, but it degrades the oxidation resistance due to the Ag diffusion during the oxidation process, which promotes extra paths for ions diffusion.