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

Autores: Sarkar, S.|Datta, S.|Das, S.|Basu, D.
Fuente: Surf. coat. technol.
203 (13), 1797-1805
2009

-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 >750oC 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 -TiAl at 800oC even up to 100 hours 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 800oC up to 100 hours. At further higher temperature such as at 1000oC, the ABK-13 and ABK-103 glass-ceramic coatings offered significant protection to the alloy up to 25 hours 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