X-ray diffractional, spectroscopic and thermo-physical properties analyses on Eu-doped lanthanum zirconate ceramic for thermal barrier coatings

To improve the protective temperature of thermal barrier coatings (TBCs), different Eu-doping ratios of La2Zr2O7 with pyrochlore structure, which are more stable in thermodynamics, were synthesized by coprecipitation-calcination method. Phase structure, grain growth kinetics, bond strength, thermo-physical properties of the doped La2Zr2O7 were investigated under different doping ratios. The results show that nano-sized doped La2Zr2O7 grains (<100 nm) grow rapidly under elevated synthesis temperature. Meanwhile the increasing Eu3+ ions lead to more imperfects, changes of bond strength, and slight disorder of the lattice. The coefficient of thermal expansion (CTE) of Eu-doped La2Zr2O7 is notably improved as Eu3+ ions increase. The thermal conductivity decreases at initial period and increases afterwards, which reaches the lowest value for the composition of (La0.6Eu0.4)2Zr2O7.