Effect of Ti-Al-Cr coatings on the high temperature oxidation behavior of TiAl alloys

The high temperature oxidation behavior of TiAl alloys coated with Ti-AI-Cr alloys using magnetron sputtering method was studied. The results showed that Ti-Al-Cr coatings improved the oxidation resistance of TiAl alloys. The weight gains at 950 degreesC for Ti-Al-Cr coatings are more than those at 1000 degreesC. Oxide formed on the surface of Ti-50Al-15Cr coating after oxidation consisted of Al2O3, whereas oxide formed on the surface of Ti-50Al-10Cr coating after oxidation is composed of a mixture of a large portion of Al2O3 and a small portion of TiO2. The effect of Ti-Al-Cr coatings on the improvement of oxidation resistance of TiAl alloys results from thermodynamic and kinetics factors contributing to Cr effect. (C) 2001 Elsevier Science B.V. All rights reserved.