Thermal decomposition routes of CrN hard coatings synthesized by reactive arc evaporation and magnetron sputtering

Abstract This study presents a comparison of the thermal decomposition of CrN hard coatings synthesized by reactive arc evaporation and magnetron sputtering. Structural changes in the coating material were determined by in-situ high-temperature X-ray diffraction and correlated to the results of simultaneous thermal analysis. Annealing temperatures up to 1440 °C in Ar and a variation in heating rates gave insights to the different decomposition kinetics for the material deposited by reactive arc evaporation and magnetron sputtering. Both single-phase CrN coatings start to decompose above 925 °C under release of nitrogen in two major reaction steps to pure Cr via the intermediate step of Cr 2 N. While the kinetics for the first decomposition reaction from CrN to Cr 2 N is different for both samples, the second step from Cr 2 N into Cr is similar. This behavior can be understood considering the differences in structure, composition, and morphology of both as-deposited coatings and their evolution during thermal analysis.