Composition and phase stability upon annealing of gradient nitride coatings

It is established that element and phase composition is stable up to 800 °C. Annealing to greatest temperatures leads to the crystallization processes of a solid solution that ensures the appearance of additional phases (CrN и σ-FeCr). Moreover, it results in the redistribution of chromium in the coating leading to an increase of a solid solution lattice parameter, migration of chromium into the substrate and σ-FeCr formation. The relationship between element and phase composition of coatings is discussed on the basis of a solid solution formation model.