Cyclic thermal shock behaviors of ZrB2-SiC laminated ceramics sintered with different-sized particles for each sublayer

Abstract

The ZrB₂-SiC ultra-high temperature ceramic is one of the most promising materials for the thermal protection system of hypersonic vehicles. However, the thermal protection system must meet the requirements of thermal protection capability and the lightweight characteristic at the same time. ZrB₂-20 vol.% SiC laminated ceramics with the same material compositions and different-sized particles for each sublayer were prepared by the spark plasma sintering method. Microstructures, grain size, elastic modulus, and hardness of the laminated ceramics were then characterized. Thermal insulation and thermal shock performance of laminated and monolithic ceramics were tested by a self-developed quartz lamp heating platform. The laminated ceramics were composed of three layers with large, medium, and small grain sizes, respectively. The elastic modulus and hardness of laminated ceramics gradually decrease layer by layer due to the different grain sizes. Compared with monolithic ceramics, the laminated ceramics have lower density and a similar cyclic thermal shock resistance, while the thermal insulation ability was obviously higher. The results proved that the ZrB₂–SiC laminated ceramics have a better application prospect in thermal protection systems.