Abstract:
Gd
2Zr
2O
7 was prepared by solid state synthesis and its phase stability and thermo-physical properties were investigated. The Gd
2Zr
2O
7-8YSZ(8%Y
2O
3-ZrO
2) double-ceramic-layer thermal barrier coatings was prepared by electron beam physical vapour deposition. The crystal structure and atomic number ratio of the top coating were analysed. Results reveal that Gd
2Zr
2O
7 powders show excellent phase stability up to 1500℃, 250℃ higher as compared to the conventional 8YSZ.The coefficients of thermal expansion of the Gd
2Zr
2O
7 bulk ranges from 8.8×10
-6-11.0×10
-6 K
-1 at the temperature from 100 to 1500℃, which are comparable to that of the 8YSZ bulk.The thermal conductivities of the Gd
2Zr
2O
7 bulk are in a level of 1.0 W(m·K)
-1 at 1000-1400℃ and about 50% lower than that of the conventional 8YSZ. The as-deposited Gd
2Zr
2O
7 coating with pyrochlore structure has a stoichiometrical composition and exhibits a typical columnar grain structure.