Preparation and Properties of BN-SiO_2 Composite Ceramics

摘要

A series of BN-SiO_2 composite ceramics with high relative densities have been fabricated by hot pressing of a mixture of hexagonal boron nitride powder and silica sol. X-ray diffraction (XRD) results show that silica are distributed in the BN matrix as noncrystalline state. Microstructure of as-sintered composite ceramics is observed by scanning electron microscopy (SEM). The influence of the secondary phase on the mechanical properties is studied by varying the silica content from 10 wt percent up to 40 wt percent. Dielectric properties of composite ceramics are also measured from 1 MHz to 2.0 GHz.