Development of the Al₂O₃-B₂O₃-SiO₂ glass for thermal barrier coating

Glass coating is an important thermal insulation technique used in the aerospace industry that serves as a thermal protection system (TPS) to protect the inner layer at elevated temperatures. This work highlights the superb mechanical and thermal properties of the B2O3-SiO2 glass systems as a surface coating for space shuttle. In the B2O3-SiO2 system, the glass transition temperature raises from 650 degrees C to 750 degrees C with increasing SiO2 content and devitrification of the alpha-cristobalite phase. The Al2O3 addition in B2O3-SiO2 glass can increase the glass transition temperature from 750 degrees C to 1000 degrees C and inhibit the alpha-cristobalite phase. The phase transition from an unstable alpha-cristobalite phase to an amorphous phase was achieved at 10 wt% Al2O3-added specimens. This study demonstrates that the Al2O3-B2O3-SiO2 glass (ABS glass) exhibits thermally stable behavior, making it an effective thermal barrier coating at elevated temperatures.