Effect of rare earth doping on thermo-physical properties of lanthanum zirconate ceramic for thermal barrier coatings |
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| Authors: | Hongming ZHOU Danqing YI |
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| Affiliation: | aSchool of Materials Science and Engineering, Central South University, Changsha 410083, China |
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| Abstract: | The effect of rare earth doping on thermo-physical properties of lanthanum zirconate was investigated. Oxide powders of various compositions La2Zr2O7 were synthesized by coprecipitation-calcination method. High-temperature dilatometer, DSC, and laser thermal dif-fusivity methods were used to analyze thermal expansion coefficient (TEC), specific heat, and thermal diffusivity. The results showed that CeO2 doped pyrochlores La2(Zr1.8Ce0.2)2O7 and La1.7(DyNd)0.15(Zr0.8Ce0.2)2O7 had higher TEC than La2Zr2O7 and La1.7Dy0.3Zr2O7. La2(Zr1.8Ce0.2)2O7, La1.7Dy0.3Zr2O7, and La1.7(DyNd)0.15(Zr0.8Ce0.2)2O7 had lower thermal conductivity than undoped La2Zr2O7. The Dy2O3, Nd2O3, and CeO2 codoped composition showed the lowest thermal conductivity and the highest TEC. Thermo-physical results also indicated that TEC of rare earth oxide doped La2Zr2O7 ceramic was slightly higher than that of conventional ZrO2-8wt.% Y2O3 (8YSZ), and its thermal conductivity was lower than that of 8YSZ. |
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| Keywords: | lanthanum zirconate thermal barrier coatings thermo-physical properties pyrochlore oxides rare earths |
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