The protection of industrial components by hard coatings at elevated process temperatures demands the development of coatings with increased thermal stability. The development of ternary and quarternary chromium based nitrides requires information and knowledge on the decomposition mechanism of binary chromium nitride (CrN). This work affords a detailed insight to the decomposition process of binary CrN hard coatings and the influence of the deposition technique. The investigated coatings were deposited by the two most common physical vapour deposition (PVD) techniques: reactive cathodic arc evaporation and reactive magnetron sputtering. The decomposition process of CrN at elevated temperatures was investigated by complementary methods of thermal analysis. Simultaneous thermal analysis (STA) and high temperature X-ray diffraction (HT-XRD) were applied to powder samples of the coatings. STA measurements comprised thermogravimetry (TG), mass spectrometry (MS) and differential thermal analysis (DTA). Mass lost, evolved gases and temperature variations were monitored in-situ at different heating rates, up to a temperature of 1440°C in argon atmosphere. HT-XRD measurements with subsequent Rietveld simulation provided data on the microstructural changes (phase fraction, crystallite size and lattice parameter) involved in the decomposition process.