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SiC composite ceramics for solar absorber and storage integration are new concentrating solar power materials. SiC composite ceramics for solar absorber and storage integration were fabricated using SiC, black corundum and kaolin as the raw materials, Co2O3 as the additive via pressureless graphite-buried sintering method in this study. Influences of Co2O3 on the microstructure and properties of SiC composite ceramics for solar absorber and storage integration were studied. The results indicate that sample D2 (5wt% Co2O3) sintered at 1 480 °C exhibits optimal performances for 119.91 MPa bending strength, 93% solar absorption, 981.5 kJ/kg (25–800 °C) thermal storage density. The weight gain ratio is 12.58 mg/cm2 after 100 h oxidation at 1 000 °C. The Co2O3 can decrease the liquid phase formation temperature and reduce the viscosity of liquid phase during sintering. The liquid with low viscosity not only promotes the elimination of pores to achieve densification, but also increases bending strength, solar absorption, thermal storage density and oxidation resistance. A dense SiO2 layer was formed on the surface of SiC after 100 h oxidation at 1 000 °C, which protects the sample from further oxidation. However, excessive Co2O3 will make the microstructure loose, which is disadvantageous to the performances of samples. [ABSTRACT FROM AUTHOR]

Mullite thermal storage ceramics were prepared by low-cost calcined bauxite and kaolin. The phase composition, microstructure, high temperature resistance and thermophysical properties were characterized by modern testing techniques. The experimental results indicate that sample A3 (bauxite/kaolin ratio of 5:5) sintered at 1 620 °C has the optimum comprehensive properties, with bulk density of 2.83 g·cm−3 and bending strength of 155.44 MPa. After 30 thermal shocks (1 000 °C-room temperature, air cooling), the bending strength of sample A3 increases to 166.15 MPa with an enhancement rate of 6.89%, the corresponding thermal conductivity and specific heat capacity are 3.54 W°(m°K)−1 and 1.39 kJ°(kg°K)−1 at 800 °C, and the thermal storage density is 1 096 kJ°kg−1 (25–800 mullite ceramics; sintering properties; high-temperature thermal storage; thermal shock resistance). Mullite forms a dense and continuous interlaced network microstructure. which endows the samples high thermal storage density and high bending strength, but the decrease of bauxite/kaolin ratio leads to the decrease of mullite content, which reduces the properties of the samples. [ABSTRACT FROM AUTHOR]

We used different SiC particle size as raw materials and via reaction bonding technique to prepare porous SiC membrane supports. The phase composition, microstructure, bending strength, open porosity, and pore size distribution were investigated as a function of SiC particle size and firing temperature. It is found that the reduction of SiC particle size not only dramatically enhances the bending strength of porous SiC membrane supports, but also slightly reduces the firing temperature duo to smaller SiC particle with higher specific surface area and higher reaction activity. Besides, the open porosity and pore size distribution are dependent on the firing temperature, but insensitive to the SiC particle size due to the pore related characters mainly controlled by the binder. The bending strength increases with the increasing of the firing temperature and with the decreasing of SiC particle size. When the firing temperature was 1 500 °C and SiC average particle size was 447.75 µm, the optimal performance were achieved, the bending strength was 15.18 MPa, the open porosity was 36.02 %, the pore size distributed at 3.09–112.47 µm, and the mean pore size was 14.16 µm. [ABSTRACT FROM AUTHOR]