Sm2（Zr1-xCex）2O7 （x=0.1, 0.2, and 0.3） ceramics were prepared by solid reaction method at 1600°C for 10 h using Sm2O3, ZrO2, and CeO2 as starting reactants. The phase compositions, microstructures, thermal ex...Sm2（Zr1-xCex）2O7 （x=0.1, 0.2, and 0.3） ceramics were prepared by solid reaction method at 1600°C for 10 h using Sm2O3, ZrO2, and CeO2 as starting reactants. The phase compositions, microstructures, thermal expansion coefficients, and partial thermal conductivities of these materials were investigated. X-ray diffraction （XRD） results reveal that Sm2（Zr0.9Ce0.1）2O7 with pyrochlore structure and Sm2（Zr1-xCex）2O7 （x=0.2 and 0.3） with fluorite structure were synthesized, and scanning electrical microscopy （SEM） images show that the microstructures of these products are very dense. The linear thermal expansion coefficients increase with increasing temperature in the temperature range from ambient to 1200°C, and the thermal expansion coefficients increase with increasing content of doped CeO2. The thermal conductivities of Sm2（Zr0.8Ce0.2）2O7 and Sm2（Zr0.7Ce0.3）2O7 decrease gradually with an increase in temperature. These results show that the synthesized ceramic materials can be explored as novel prospective candidate materials for use in new thermal barrier coating systems in the future.展开更多
Resonant-cavity technique was introduced to measure the permittivity and loss tangent of low-loss dielectrics. The dielectric properties at 9-10 GHz are measured accurately at the temperature up to 800 ℃ by the reson...Resonant-cavity technique was introduced to measure the permittivity and loss tangent of low-loss dielectrics. The dielectric properties at 9-10 GHz are measured accurately at the temperature up to 800 ℃ by the resonant cavity technique. The only electrical parameters that need to be measured are quality factors （Q） and resonant length （L） of resonant cavity loaded and unloaded with dielectric sample. Moreover, the error caused by thermal expansion effect was resolved by error analysis and experimental calibration.展开更多
基金supported by the Doctor Research Fund of Henan Institute of Engineering (No. D2007012)
文摘Sm2（Zr1-xCex）2O7 （x=0.1, 0.2, and 0.3） ceramics were prepared by solid reaction method at 1600°C for 10 h using Sm2O3, ZrO2, and CeO2 as starting reactants. The phase compositions, microstructures, thermal expansion coefficients, and partial thermal conductivities of these materials were investigated. X-ray diffraction （XRD） results reveal that Sm2（Zr0.9Ce0.1）2O7 with pyrochlore structure and Sm2（Zr1-xCex）2O7 （x=0.2 and 0.3） with fluorite structure were synthesized, and scanning electrical microscopy （SEM） images show that the microstructures of these products are very dense. The linear thermal expansion coefficients increase with increasing temperature in the temperature range from ambient to 1200°C, and the thermal expansion coefficients increase with increasing content of doped CeO2. The thermal conductivities of Sm2（Zr0.8Ce0.2）2O7 and Sm2（Zr0.7Ce0.3）2O7 decrease gradually with an increase in temperature. These results show that the synthesized ceramic materials can be explored as novel prospective candidate materials for use in new thermal barrier coating systems in the future.
文摘Resonant-cavity technique was introduced to measure the permittivity and loss tangent of low-loss dielectrics. The dielectric properties at 9-10 GHz are measured accurately at the temperature up to 800 ℃ by the resonant cavity technique. The only electrical parameters that need to be measured are quality factors （Q） and resonant length （L） of resonant cavity loaded and unloaded with dielectric sample. Moreover, the error caused by thermal expansion effect was resolved by error analysis and experimental calibration.
