De nombreux matériaux céramiques et métalliques seront endommagés s'ils sont soumis à des températures élevées., réduction, oxydation et autres environnements pendant une longue période. De tels problèmes peuvent être résolus en recouvrant la surface du matériau avec un matériau de revêtement composé qui peut rester stable dans l'environnement d'utilisation.. La mullite a des propriétés chimiques stables, good corrosion resistance, and excellent performance, which makes it widely used in compound coatings and other aspects.

Because mullite has excellent high-temperature mechanical properties, chemical stability, creep resistance, thermal shock stability, faible coefficient de dilatation thermique, etc., it is widely used in the field of high-temperature thermal materials. However, mullite has no dislocation slip system. When the external load exceeds a certain limit, more microcracks will be generated inside to consume energy, causing catastrophic damage to mullite ceramics. Donc, how to toughen mullite materials has become a hot topic in recent years.

Researchers at home and abroad have conducted a lot of research on mullite composites and have achieved certain results in the field of mullite toughening. Mullite composites include mullite matrix, mullite fiber, etc.. Mullite composites can reduce the inherent brittleness of mullite material systems and improve their strength and toughness. After years of efforts, the thermodynamic behavior of mullite-based composite materials has been improved by particle reinforcement (SiC, ZrO2) or flake reinforcement, and some progress has been made in the toughening of mullite.