X-band electromagnetic absorption and mechanical properties of mullite/Ti3AlC2 composites

Abstract

Aiming to enhance the electromagnetic wave absorption (EWA) property of mullite ceramics, MAX phase of Ti3AlC2 was introduced into mullite ceramics for the first time. Significantly improved EWA and mechanical performance of mullite ceramics were achieved simultaneously by introducing Ti3AlC2 via a pressureless sintering process. Results indicated the increasing sintering temperature promoted the densification of as-prepared composites and induced the decomposition of Ti3AlC2 to different degrees. The composites sintered at 1450 °C possessed the optimal mechanical performance with flexural strength, fracture toughness and Vickers hardness of 211.78 MPa, 5.28 MPa m1/2 and 9.36 GPa, respectively. The improved mechanical properties were mainly attributed to the enhanced densification and even-distributed TiC particles in the mullite matrix. Moreover, polarization loss resulting from the unpaired defect and newly formed interfaces, and conductance loss originating from the highly conductive TiC particles, played a major role in the considerable improvement in EWA properties of mullite-based composites. The minimum RL value of composites sintered at 1450 °C reached −35.5 dB with a thickness of 2.65 mm. By regulating the decomposition degree of Ti3AlC2, the mechanical and EWA performance of mullite ceramics can be effectively enhanced. This study will provide an effective reference for the preparation of EWA materials with excellent comprehensive properties.