Mechanical and Microwave-Absorption Properties of Si3N4 Ceramic with SiCNFs Fillers

Aiming to optimize the mechanical and microwave absorption properties of Si3N4 ceramics, SiC nanofibers (SiCNFs) are introduced into Si3N4 ceramics by gel casting. The results indicate that flexural strength of as-prepared Si3N4-based ceramics decreases from 362 to 284.2 MPa, while the fracture toughness increases from 3.4 to 5.2 MPa center dot m(1/2), as the SiCNFs fillers in the Si3N4 matrix increase from 0 to 8 wt%. Moreover, both complex permittivity and dielectric loss are significantly enhanced after introduction of SiCNFs fillers into Si3N4 ceramics. The investigation of microwave absorption demonstrates that much enhanced microwave attenuation abilities is achieved in the Si3N4 ceramics with different content of SiCNFs fillers. Especially, the Si3N4 ceramics with 8 wt% SiCNFs fillers exhibit excellent microwave absorption properties at thin thickness, indicating favorable potential application as high-performance microwave absorbing materials.