Microstructural evolution and kinetics analysis of aluminum borate ceramics via solid-state reaction synthesis

Aluminum borate ceramics (ABCs) with a skeleton structure of rod-like crystals were established via a solid-state reaction synthesis. The influence of heat treatment systems on the phase composition and microstructural evolution of an anisotropic grain were firstly studied. Next, the impact of boric acid content on the activation energy of reaction, microstructure, mechanical properties, and neutron shielding capability were investigated. The results demonstrate that orthorhombic Al18B4O33 formed between 900 degrees C and 1000 degrees C which was the stable phase during heating treatment. In addition, increasing the boric acid content was favorable for reducing the activation energy of forming aluminum borate, resulting in increased in situ formation and growth of aluminum borate whiskers in fired samples. Next, mircropores could be generated by the decomposition of boric acid at high temperatures, which had a considerable influence on the physical properties of the sample. Furthermore, the Monte Carlo particle transport program simulation and neutron shielding experiments showed that the prepared ABCs could shield neutron effectively manifested as possessing a high neutron absorption cross-section in the case of porous materials. Moreover, ABCs have potential application value as thermal insulation material in the nuclear energy field.