Influence of dysprosium oxide doping on thermophysical properties of LaMgAl11O19 ceramics

This paper deals with the influence of dysprosium oxide doping on thermophysical properties of LaMgAl11O19 ceramics. LaMgAl11O19 ceramic powders doped with different contents of dysprosium oxide were pressureless-sintered at 1700 oC for 10 h in air to fabricate dense bulk ceramics. La1-xDyxMgAl11O19 (x = 0, 0.1, 0.2, 0.3) ceramics have a relative density of 90.7-96.0%, and exhibit a single phase of magnetoplumbite structure. Thermal diffusivity and thermal expansion coefficients of La1-xDyxMgAl11O19 ceramics were measured with a laser flash method and a high-temperature dilatometer. Thermal diffusivity of La1-xDyxMgAl11O19 ceramics decreases with increasing Dy2O3 content at identical temperature levels. The measured thermal conductivity of La1-xDyxMgAl11O19 ceramics is located in the range of 2.52-2.89 W m-1 K-1 at 1200 oC. Thermal expansion coefficient of La0.8Dy0.2MgAl11O19 ceramic is slightly higher than that of undoped LaMgAl11O19 ceramic at identical temperature levels.