Hardness evaluation of W–Si–N sputtered coatings after thermal degradation

The purpose of this research work was to study the effect of the degradation by high temperature oxidation, which is inevitable in real service conditions, on the mechanical properties of the remaining unoxidised W–Si–N films. For this, an ultramicroindentation technique was used on three amorphous as-deposited coatings, after removing the top oxide scales, which had been previously formed by air oxidation at a temperature range of 600–800 °C. The results obtained indicate that the oxidation process does not lead to mechanical degradation of the unoxidised films. Hardness increases with increasing oxidation temperature, a similarity that is observed for the same coatings during thermal annealing in an Ar/H2 atmosphere.