Low‐temperature and pressureless in‐situ self‐assembled SiC w / SiC composite ceramics for solar thermal absorber and storage integration

Compared with current research of simply improving the efficiency of thermal absorber or thermal storage, integrating two devices into one fundamentally avoids the heat transfer loss between the two devices. In-situ self-assembled SiCw(SiC whisker)/SiC composite ceramics for integrated thermal absorber and thermal storage were pressurelessly prepared from graded SiC, AlN, and Si powders by layered powder embedded sintering in a low temperature range from 1450°C to 1650°C. After sintered at 1550°C, sample A4 with 10.39 wt% Si not only exhibits optimal mechanical properties and excellent thermal shock resistance, but also has high thermal conductivity, thermal storage capacity, and solar absorptance as 6.74 W·(m K)−1, 984.75 kJ·kg−1, and 91.12%, respectively. Results indicate that the in-situ self-assembled SiC whiskers, formed by carburization reaction via VS mechanism in the stacking voids of SiC matrix, could greatly enhance the mechanical and thermal properties. We creatively proposed that the as-prepared SiCw/SiC is promising to apply in integrated thermal absorber and storage system of solar thermal power generation.