Fabrication of polymer-derived SiON ceramics with excellent wave-transparent properties by crosslinking temperature optimization and heat treatment

Current research on polymer-derived ceramics (PDC) SiON remains extremely limited, particularly in the understanding of its dielectric properties. In this study, a designed three-stage process was employed to convert commercial polysilazane into PDC-SiON, enabling precise control over its composition and microstructure through controllable oxygen incorporation, nitrogen doping pyrolysis, and subsequent high-temperature decarbonization. The 1500 °C heat treatment was employed to simultaneously reduce residual carbon, facilitate ceramic conversion and Si–O–N network reorganization, induce phase separation, and promote partial crystallization of Si₃N₄. The resulting ceramics exhibit excellent performance at 10 GHz, with the relative permittivity as low as 3.27, a tangent loss of 0.003, and a mass loss of less than 5% after thermal treatment in nitrogen at 1500 °C, demonstrating outstanding thermal stability. These results not only elucidate the structure–property relationships in PDC-SiON but also confirm its significant potential as a candidate material for high-temperature wave-transparent components in hypersonic vehicles.