Reaction Mechanism and Thermal Insulation Property of Al-deposited 7YSZ Thermal Barrier Coating

To increase the performance and efficiency of thermal barrier coating （TBC）, it is important to improve the thermal insulation property. In this work, a columnar AI film was deposited at the top of 7 wt% yttria- stabilized zirconia （7YSZ） TBC by magnetron sputtering. A vacuum heat treatment was then carried out to improve the insulation property of Al-deposited TBC. Reaction mechanism of AI-ZrO2 system in AIdeposited TBC was studied by differential thermal analysis （DTA）. The phase structures of the assprayed TBC, the Al-deposited and vacuum-treated TBC were characterized. The microstructure evolution of M-deposited TBC was illustrated after vacuum heat treatment. And the insulation property of the assprayed TBC and treated TBC was compared. The results show that a multi-scaled layer, consisting of micron/ nano structured α-Al2O3 and AI3Zr grain was in situ synthesized at the top of 7YSZ coating via vacuum heat treatment. The TBC with the multi-scaled overlay has better insulation property than the asspraved TBC.