Oxidation inhibition of γ-TiAl alloy at 900°C by inorganic silicate composite coatings

Inorganic silicate composite coatings on gamma-TiAl were fabricated by air spraying. The oxidation behaviour of the alloy was investigated at 900 degrees C. The results indicated that rapid oxidation occurred in the gamma-TiAl, and multilayered non-protective TiO2 and Al2O3 scales formed. For coated gamma-TiAl alloy, the oxidation was markedly inhibited; a thin Al2O3 layer was detected, which improved the oxidation resistance of the alloy. The low oxygen partial pressure at the interface of the coatings and the alloy promotes the preferentially oxidation of Al in the gamma-TiAl substrate, and the outward diffusion of Ti to form TiO2 was retarded. (C) 2013 Elsevier Ltd. All rights reserved.