Characteristics of (Cr1−x, Alx) N films prepared by pulsed laser deposition

Chromium aluminum nitride ((Cr1−x, Alx) N) films have been successfully prepared by pulsed laser deposition (PLD). The (Cr1−x, Alx) N film, which is hard and resistant against wear and oxidation, is one of the most promising pseudobinary nitrides for applications in the protective coatings. The film was synthesized by depositing chromium and aluminum metal vapors in nitrogen. Experiments were carried out by changing the surface area ratio of the target (Al/(Cr+Al)) from 0 to 100%. The hardness of the (Cr1−x, Alx) N films showed the maximum value (HV∼3000) at x = 0.75. Phase transition from B1 (NaCl) structure to B4 (würtzite) structure occurred above x = 0.75, being in a reasonable agreement with the theoretical prediction. As a result of oxidation test, the CrN film oxidized at near 600°C, whereas the (Cr0.5, Al0.5) N film was not detected the existence of oxide in the annealing temperature range R.T. to 900°C.