Study on magnesia alumina spinel heat storage ceramics for solar thermal power generation

Solar thermal storage ceramic materials use photothermal power generation technology to store heat energy, which is an important way to use clean energy and reduce carbon emissions. In this paper, MgAl 2 O 4 ceramics were prepared by pressureless sintering with fused magnesia and α‐Al 2 O 3 as the primary raw materials and TiO 2 as the additive. The phase composition, microstructure, physical properties, thermal shock resistance, and thermal physical properties of MgAl 2 O 4 thermal storage ceramics were studied. The results show that the main crystalline phase of B4 is MgAl 2 O 4 and the secondary crystalline phase is MgTi 2 O 5 . Ti 4+ is dissolved into MgAl 2 O 4 lattice, which distorts the lattice, reduces activation energy, and promotes sintering. The sample B4 (69.73 wt% α‐Al 2 O 3 , 30.27 wt% fused magnesia, and 7 wt% TiO 2 ) sintered at 1510°C had the best comprehensive physical properties, and its bending strength and bulk density were 89.41 MPa and 3.27 g/cm 3 , respectively. After 30 thermal shock cycles, the bending strength of the sample B4 is slightly lost. The thermal stress generated during the expansion and contraction of the grain volume led to the decrease of the bending strength. From room temperature to 1000°C, the specific heat capacity of sample B4 is .44–1.25 J/(g·K). The heat capacity increases with the increase of temperature, and the heat storage density increases. The heat storage density is 1218.75 kJ/kg (1000°C). Heat capacity increases with temperature due to intensified lattice vibration at high temperatures. Therefore, magnesia alumina spinel ceramics show great potential in solar thermal energy storage.