BN interface in SiC/SiC composites: A review on structural characteristics, service failure mechanisms, and optimization strategies

In silicon carbide fiber-reinforced silicon carbide (SiC/SiC) composites, the boron nitride (BN) interface is critical for load transfer and toughening, yet its performance is governed by the interplay between microstructure and service environment. This review systematically examines the structural characteristics and failure mechanisms of the BN interface across a wide temperature range. Key optimization strategies are thoroughly discussed, focusing on interface engineering, matrix modification, and system-level integration with environmental barrier coatings (EBCs) for enhanced protection. Finally, promising research directions are outlined to guide future developments toward durable and reliable SiC/SiC composites under extreme conditions.