Properties and Applications of Ceramic Matrix Composites

Ceramic matrix composites (CMCs) are a class of novel ceramic materials that emerged and gradually developed during the 1980s. Broadly speaking, CMCs not only retain the inherent advantages of traditional ceramics—such as high-temperature resistance, wear resistance, resistance to high-temperature creep, low thermal conductivity, low coefficient of thermal expansion, chemical corrosion resistance, high strength, high hardness, and low density—but also overcome the limitations of ceramics regarding high brittleness and low toughness. They exhibit fracture behaviors similar to those of certain metals, are insensitive to cracks, and rarely undergo catastrophic failure in the presence of damage. Consequently, they find extensive application in operating environments where organic-matrix and metal-matrix materials fail to meet performance requirements—particularly those involving high temperatures—and have thus become an ideal class of high-temperature-resistant materials. It is projected that in the 21st century, CMCs will become the preferred materials for replacing metals and their alloys in the hot-section structures of engines. In light of this, numerous nations are actively conducting research into CMCs, an endeavor that is expected to significantly broaden their scope of application. Fields in which CMCs have already been commercialized—or are on the verge of commercialization—include aerospace, mechanical processing, chemical engineering, and energy.

Currently, fiber-reinforced ceramic matrix composites primarily comprise two categories: structural/thermal-protection composites—such as carbon fiber-reinforced silicon carbide (C/SiC), silicon carbide fiber-reinforced silicon carbide (SiC/SiC), and ultra-high-temperature materials like HEB, ZrB, HfC, and ZIC—and structural/radome composites—such as quartz fiber-reinforced quartz ceramics (SiO₂/SiO₂), silicon nitride fiber-reinforced ceramic matrix composites, and alumina fiber-reinforced alumina (Al₂O₃/Al₂O₃) matrix composites.