Thermal stability and oxidation resistance of Ti-Al-N coatings

► Ti1 − xAlxN coatings with varied Al content and structure were prepared by magnetron sputtering. ► Ti1 − xAlxN coatings with an Al content closer to the solubility limit favor an earlier decomposition. ► C-Ti0.48Al0.52N outperforms the other coatings during hardness vs. temperature tests. ► Single phase wurtzite Ti0.25Al0.75N exhibits the best oxidation resistance. ► Mixed structured coatings underperform during hardness vs. temperature and oxidation tests.