Structural-Functional Integrative Mullite_f/SiBN Composites with Excellent Wave-Transparent and Mechanical Properties

摘要

A structural-functional integrative wave-transparent material, consisted of BN coating and SiBN substrate, is synthesized through precursor infiltration pyrolysis (PIP) process. The technical parameters and procedures are obtained according to the key properties of the precursors. It was show that compact substrate and weak interface enhance the strength, and porous structure improvesthe dielectric performance of the composite. The composite exhibits good bending strength (-95.12 MPa), tensile strength (-34.95 MPa) and compressive strength (-80.92 MPa). Moreover the composite displays a low dielectric constant (4.17) and a low loss tangent (9.7×10~(-3)) at room temperature. The composite has a low changing rate of dielectric constant (-2.01% per 100°C). These results imply that the composite with excellent mechanical and dielectric properties can be an excellent wave-transparent material applied in the fields of aerospace.