Microstructural characteristics, properties, synthesis and applications of mullite: a review

Abstract

Mullite, an intermediate phase of the binary alumina-silica system, is one of the most important phases of ceramic products containing alumina and silica in the initial composition. Its stoichiometry ranges from 3Al2O3.2SiO2 (3:2) to 2Al2O3.SiO2 (2:1) and its crystalline structure is orthorhombic, characterized by the presence of octahedral chains of AlO6 interconnected by tetrahedral chains of aluminum-oxygen and/or silicon-oxygen (AlO4/SiO4). Properties such as high chemical and thermal stability, low thermal expansion and conductivity, and good mechanical strength enable a wide range of applications. Due to the relevance of this material, it is important for the scientific community to understand its microstructural characteristics, properties, methods of synthesis, and various applications. Therefore, this article aimed to make a comprehensive review on the mullite to gather and present to the reader a series of relevant information that makes it possible to deepen the knowledge about mullite.