Thermal shock and self-healing behavior of the enamel composite coatings with addition of various nanoparticles at temperatures of 700 and 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 degrees C to room temperature. With addition of nanoparticles of ZrB2, The enamel composite coating provides well oxidation protection meanwhile high thermal shock resistance at temperatures of 700 and 800 degrees C. Cracks are able to heal owing to the high thermal stability of ZrB2 and its unique oxidation products.