Microwave-absorption properties of heterostructural SiC nanowires/SiOC ceramic derived from polysiloxane

A kind of heterostructural SiC nanowires/SiOC composite ceramic is obtained by directly pyrolysis of mixture of poly(methylhydrosiloxane) (PMHS) and 2, 4, 6, 8-tetramethy1-2, 4, 6, 8-tetravinylcyclotetrasiloxane (TMTV) polysiloxane. The mechanical of in-situ growth SiC nanowires is mainly attributed to the initial phase separation of SiOC ceramic and subsequent solid-phase reaction of SiO and C phases. Due to the formation of SiC nanowires in amorphous SiOC ceramic, the interfaces of the SiOC particles are raising, which leads to the escalation of interfacial scattering. Thus, the absorption properties are promoted by the electronic dipole polarization and interfacial scattering. Results show that the minimal reflection coefficient (RCmin) of hybrid SiC nanowires/SiOC ceramic decreases with the increasing annealed temperature, and reaches - 10 dB at 13 GHz at the thickness of 3.8 mm when the heat-temperature gets to 1400 degrees C.