Mechanical and dielectric properties of porous Si2N2O-Si3N4 in situ composites

Mechanical and dielectric properties of porous Si2N2O-Si3N4 in situ composites fabricated for use as radome by gel-casting process were investigated. The flexural strength of the Si2N2O-Si3N4 ceramics is 230.46 +/- 13.24 MPa, the complex permittivity of the composites varies from 4.34 to 4.59 and the dissipation factor varies from 0.00053 to 0.00092 from room temperature to elevated temperature (1150 degrees C) at the X-band. In the porous regions, some Si2N2O fibers (50-100 nm in diameter) are observed which may improve the materials properties. (c) 2008 Elsevier Ltd and Techna Group S.r.l. All rights reserved.