A novel low thermal conductivity thermal barrier coating at super high temperature

Abstract Novel high temperature-resistant thermal barrier coatings are urgently required as the stringent operating environment. High temperature property studies of zirconia matrix thermal barrier coatings doped with Cr3+, Mg2+, Si4+, and Mn4+ ions prepared by solid phase reaction method are reported. The results of X-ray diffraction measurements prove the coatings prepared by air plasma spray are predominately in a non-transformable cubic structure which is the most stable phase structure at high temperature. Hot corrosion tests of molten salts (at 900 °C) and oxides (at 1400 °C) have been carried out, and the results show that the corrosions lead to the coating surface deterioration. The thermal conductivity of coating doped with Cr3+ is the lowest value until to 1600 °C, and the mechanism has been analyzed. The antioxidant ablation results also proved that the coating doped with Cr3+ showed the best heat-insulating property. All the results show that the coating doped with Cr3+ will be a promising thermal barrier coating.