Microstructure and properties of forsterite-zirconia composite ceramics for solar thermal storage

Abstract

Solar thermal power generation is an important direction of energy utilization, and thermal storage materials are the key to ensure the continuous use of energy. In this paper, forsterite - zirconia composite ceramics were prepared by adding different contents of 3Y–ZrO2 and their physical properties, phase composition, microstructure thermal shock resistance and thermal physical properties were studied. The results showed that the water absorption, bulk density and bending strength of sample A3 sintered at 1600 °C (59.10 wt% fused magnesia, 40.90 wt% quartz and 30 wt% 3Y–ZrO2) were 0.35 %, 3.27 g/cm3 and 83.66 MPa, respectively. The crystal phase of sample A3 was forsterite and c-ZrO2. Mg2+ and Y3+ replace Zr4+, formed oxygen vacancy in the anion position, distort the coordination layer and release some interlayer stress to promote the stability of c-ZrO2. In the sintering process, the zirconia solid solution existed in the form of second phase, which reduced the growth rate of periclase, facilitated the pore discharge in the sample and promotes sintering. The thermal conductivity of forsterite - zirconia composite ceramics at room temperature was 5.52 W/(m·K). At 1000 °C, the specific heat capacity and heat storage density were 1.09 J/(g·K) and 1062.36 kJ/kg, respectively. The forsterite - zirconia composite ceramic prepared in this study was suitable for high temperature environment, its heat storage capacity was excellent, and it was suitable for high temperature heat storage system.