Oxidation protection of gamma-titanium aluminide using glass–ceramic coatings

γ-TiAl intermetallic alloys are presently considered an efficient structural material for advanced turbine blades and aero-engine components due to their various advantages compared to the traditionally used superalloys. However, their poor oxidation resistance at temperatures > 750 °C severely limits their wider application. The present study dealt with the improvement of oxidation resistance of this alloy by applying impervious glass–ceramic coatings by vitreous enameling technique. Results showed that MgO–SiO2–TiO2 glass–ceramic coating could offer excellent oxidation resistance to γ-TiAl at 800 °C even up to 100 h with negligible weight gain (~ 0.10 mg/cm2) compared to that of the bare alloy (~ 1.3 mg/cm2). The coatings those were belonging from BaO–MgO–SiO2, ZnO–Al2O3–SiO2 and BaO–SiO2 systems also extend appreciable improvement in the oxidation resistance of the alloy at 800 °C up to 100 h. At further higher temperature such as at 1000 °C, the ABK-13 and ABK-103 glass–ceramic coatings offered significant protection to the alloy up to 25 h of exposure in air with minimum weight gain (~ 0.34 mg/cm2). However, after that the coated layers started to peel off from the alloy surface.