Structural effects of energy input during growth of Ti1 − xAlxN (0.55 ≤ x ≤ 0.66) coatings by cathodic arc evaporation

The results also show a strong decrease in grain size as either of the studied parameters is increased. The grain refinement is found to be correlated to an increase in the amount of wurtzite phase, in addition to the majority NaCl phase, as detected by X-ray diffraction. It is proposed that the probability of forming wurtzite becomes higher as either the energy available increases (due to thermal activation) or the energetic difference between the two phases becomes smaller (e.g., as the Al content is increased from x = 0.55 to x = 0.66). This explanation is consistent with the evolution of grain size and phase content as functions of process conditions or Al content, and is further supported by the results on residual stress evolution.