High temperature stable amorphous SiBCN microwave absorption ceramics derived from one-pot synthesis of single-source precursors

Abstract

Silicoboron carbonitride (SiBCN) ceramics are developed as microwave absorption material for high-temperature environments under multicomponent doping and in-situ crystallization. In this study, amorphous SiBCN microwave absorption ceramics was derived from single-source hyperbranched polyborosilazanes containing benzene rings synthesized by the one-pot method. The carbon element and ordered carbon ratio of the pyrolyzed SiBCN ceramics enhanced with an increase in the proportion of dichlorodiphenylsilane. By adjusting the monomer ratio and pyrolysis temperature of ceramic precursor, the polymer derived ceramics (PDCs) could achieve good microwave absorption properties while remaining amorphous, with minimum reflection coefficient (RCmin) up to -30.79 dB and maximum effective absorption bandwidth (EABmax) up to 4.07 GHz. Meanwhile, the PDC-SiBCN ceramics exbibited outstanding high temperature stability with essentially no mass loss in argon (Ar) and air atmospheres until 1400 °C. This novel, convenient PDC-SiBCN preparation with potential for scaled-up production provides new ideas for microwave absorption materials for applications in extreme environments.