Oxidation behavior of the AlN coatings on the TiAl alloy at 900 °C

Oxidation behavior of the AlN coatings and the TiAl alloy is investigated at 900 °C. Results indicate that the application of the AlN coatings prepared by arc ion plating with different negative voltages on the TiAl alloy can improve its high temperature oxidation resistance. AlN in the coatings can be oxized to Al2O3 at 900 °C. After oxidation for 100 h, a protective Al2O3 scale without AlN is formed, and the Ti3Al/Ti2AlN/ Ti3Al interface is detected beneath that. The AlN coating with negative bias voltage 200 V exhibits higher oxidation resistance than others.