Preparation and thermo-physical properties of La_1-xNd_xMgAl₁₁O₁₉ (x = 0, 0.1, 0.2) ceramics

La_1-xNd_xMgAl₁₁O₁₉ (x = 0, 0.1, 0.2) ceramic powders were synthesized by chemical-coprecipitation and calcination method, and were then pressureless-sintered at 1700 °C for 10 h in air to fabricate dense bulk materials. La_1-xNd_xMgAl₁₁O₁₉ ceramics were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The thermal expansion coefficients (TECs) and thermal diffusivity coefficients of La_1-xNd_xMgAl₁₁O₁₉ ceramics were studied with a high-temperature dilatometer and a laser flash diffusivity technique from room temperature up to 1200 °C. La_1-xNd_xMgAl₁₁O₁₉ (x = 0, 0.1, 0.2) ceramics exhibited a defect magnetoplumbite structure. The TECs of LaMgAl₁₁O₁₉ and La_0.8Nd_0.2MgAl₁₁O₁₉ are 8.49 × 10^-6 K^-1 and 8.58 × 10^-6 K^-1 at 1200 °C, respectively. The thermal conductivity of La_1-xNd_xMgAl₁₁O₁₉ (x = 0, 0.1, 0.2) ceramics locates in the range of 2.62-3.87 W m^-1 K^-1 from room temperature to 1200 °C.