Microwave absorption properties of PDCs-SiC(N) based on heat treatment at different temperatures

Polymer-derived ceramics (PDCs) exhibit diverse microstructures and varying levels of free carbon after pyrolysis at different temperatures, resulting in distinct wave-absorbing capabilities. In this study, PCS, PSN1, and PSN2 with different free carbon concentrations were subjected to heat treatment, followed by systematic characterization of their microstructures, particularly the transformation process of free carbon. Subsequently, the dielectric constants and microwave-absorbing properties of the heat-treated PDC powders within the 2–18 GHz range were determined using the coaxial method. Finally, an analysis was conducted on the relationship between loss mechanisms and microstructure in PDCs to establish a foundation for preparing broadband wave-absorbing ceramic matrix composites.