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Mullite ceramic materials have a number of excellent properties that make them an excellent choice for solar heat absorber materials in Concentrating Solar Power (CSP) systems. In this study, the effects of adding Co 2 O 3 and Fe 2 O 3 on the properties of mullite-based ceramics were studied, aiming to get excellent absorption rate and thermal shock resistance. The results show that the sample C2 (45.05 wt% 75 calcined bauxite, 45.05 wt% Suzhou clay, 9 wt% Fe 2 O 3 , 3 wt% Co 2 O 3) sintered at 1400 °C has the best comprehensive performance, with a bending strength of 143.28 MPa and a solar absorption rate of 92.2 % in the wavelength range of 0.3–2.5 μm. The bending strength increased by 31.36 % after thermal shock cycles for 30 times (1000 °C ∼ room temperature, air cooling). Generation of iron cobalt spinel and lattice distortion caused by Fe3+ and Co3+ into the mullite lattice combined to promote the absorption rate. In the meantime, the main crystalline phase columnar mullite showed a tight continuous interlaced network structure. The fracture mode was mainly transgranular fracture, which endowed C2 excellent thermal shock resistance. [ABSTRACT FROM AUTHOR]

In order to study the performance and feasibility of magnesia‐alumina spinel (MgAl2O4) ceramics for thermal storage in solar thermal power generation, MgAl2O4 was prepared by theoretical composition using α‐Al2O3 as aluminium source, fused magnesia, magnesite, and light burned magnesia as different magnesium sources and kaolin as additive. The effects of magnesium source and the additive on sintering properties, thermal shock resistance and thermal properties of MgAl2O4 ceramics were researched. The results shown sample A1 (with fused magnesia) sintered at 1670°C possessed the optimum comprehensive properties, the bending strength increased by 7.71% after 30 thermal shock times (room temperature‐1000°C, air cooling), the specific heat capacity was 1.05 J/ (g·K). Therefore, the MgAl2O4 ceramics exhibited great potential in high‐temperature thermal storage material. [ABSTRACT FROM AUTHOR]

Zirconia-alumina composite ceramics are the preferred materials for high temperature and thermal shock applications because of their excellent mechanical properties. In this paper, La 2 O 3 doped zirconia-alumina composite ceramics were prepared by using fused zirconia corundum and ZrO 2 as starting materials. The effects of La 2 O 3 on the phase composition, microstructure and properties of the composite ceramics were investigated by XRD and SEM. The results show that La 2 O 3 can reduce the sintering temperature and improve the bending strength of the samples. The bending strength and fracture toughness of the composite ceramics with 1.5 wt% La 2 O 3 sintered at 1480 °C are 299.17 MPa and 5.61 MPa m1/2, respectively. The strength loss rate of the sample after 30 thermal shocks (room temperature ∼ 1000 °C) is 2.67%, SEM shows that the grain sizes of alumina and zirconia in the sintered sample were about 5 μm and 2 μm, respectively. After 30 thermal shocks, the phase composition and microstructure of the sample have no significant change, indicating good thermal shock resistance of the composite ceramics. The excellent thermal shock resistance ensures porous medium combustion materials has a long service life. [ABSTRACT FROM AUTHOR]

Solar absorption and thermal storage integrated ceramics (SATS ceramics) are new thermal storage materials that directly absorb sunlight, which improve the solar-to-thermal conversion efficiency. In this paper, SATS ceramics were developed by using calcium and iron-rich steel slag as the starting material. On the basis of composition characteristics of steel slag and performance requirements of SATS ceramics, the target phases of magnesioferrite spinel (MgFe 2 O 4) and monticellite (CaMgSiO 4) were designed and successfully synthesized in the SATS ceramics by the addition of magnesite and quartz. Phase composition, microstructure, physical properties, thermal shock resistance, solar absorptance and thermal storage performance were investigated. The results show that SATS ceramics with the addition of magnesite and quartz possess better properties than the ceramics prepared from 100 wt% steel slag. Particularly, the solar absorptance and thermal storage density of the SATS ceramics with the target phase of MgFe 2 O 4 are 84.7% and 1057.57 kJ kg−1 (25–800 °C), which increased by 3.04% and 21.87% compared to reference sample, respectively. In addition, it still presents higher strength of 64.83 MPa after 30 thermal shock cycles (25–800 °C) than the other samples, indicating good thermal shock resistance. Surprisingly, the utilization rate of steel slag reaches up to 97.89 wt%. This work not only develops a low-cost SATS ceramics, but also provides a new high-value utilization approach to steel slag. [ABSTRACT FROM AUTHOR]