Synthesis and Thermophysical Properties of Ceramics Based on Magnesium Gallate

A ceramic was produced from a nanocrystalline magnesium gallate powder synthesized by the gel combustion method, and the thermal diffusivity of the ceramic at high temperatures was experimentally investigated. The phase and chemical composition of the MgGa2O4 ceramic powder was studied by X-ray powder diffraction analysis, X-ray fluorescence spectroscopy, and CHNS elemental analysis. The microstructural parameters of the obtained ceramic material were determined by scanning electron microscopy. The average particle size of the MgGa2O4 powder was found to be 80 nm. The ceramic produced by sintering the compacted MgGa2O4 powder at 1673 K in air had a density of 4670 kg/m3 (88% of the theoretical density). The average size of the crystalline grains of the ceramic after sintering did not exceed 1 μm. The thermal diffusivity of the ceramic based on MgGa2O4 in the temperature range 300–1173 K was for the first time studied by the laser flash method. It was found that its thermal conductivity in the studied temperature range decreased from 2.25 to 0.96 W/(m K).