Thermal shock and self-healing behavior of the enamel composite coatings with addition of various nanoparticles at temperatures of 700 and 800 °C.

• Enamel composite coatings with addition of Ni, Fe or ZrB 2 are prepared on TiAl alloy. • The enamel composite coating with ZrB 2 nanoparticles provides well oxidation protection and high thermal shock resistance. • Cracks are self-healed in the enamel composite coating at temperature of 700 or 800 °C. Enamel coating only provides high oxidation resistance for alloys at temperatures below or close to softening temperature, where cracks are difficult to self-heal due to the high viscous. In this study, the enamel composite coating with nanoparticles of Ni or Fe suffers cracking and local spallation under thermal shock from 700 °C to room temperature. With addition of nanoparticles of ZrB 2 , The enamel composite coating provides well oxidation protection meanwhile high thermal shock resistance at temperatures of 700 and 800 °C. Cracks are able to heal owing to the high thermal stability of ZrB 2 and its unique oxidation products. [ABSTRACT FROM AUTHOR]