Structural evolution and high-temperature sensing performance of polymer-derived SiAlBCN ceramics

In situ temperature monitoring has become extremely imperative in high-temperature harsh environments and polymer-derived ceramics (PDCs) as sensing materials have attracted great attention. However, the stability and oxidation/corrosion resistance of PDCs cannot be simultaneously achieved at the moment, limiting their practical application. Herein, polymer-derived SiAlBCN ceramics were synthesized via polymer conversion method under different pyrolysis temperatures. Their microstructure evolution, high temperature sensing properties and stability were investigated in detail. The results show that the amorphous SiAlBCN phase grows more ordered and the size of the free carbon phase enlarges with the increasing temperature. The defects concentration displays a decreasing tendency. Concurrently, the SiAlBCN ceramics as sensing materials exhibit a good temperature-resistance property from room temperature to 1100 °C. The fabricated SiAlBCN temperature sensor possesses excellent stability, repeatability and accuracy. Moreover, SiAlBCN ceramics exhibit distinguished oxidation/corrosion resistance after 100 h treatment at 1200 °C in a water/oxygen environment, which is attributed to their low corrosive rate constant (0.57 mg·(cm²·h)⁻¹) and oxidative rate constant (3.43 mg²·(cm⁴·h)⁻¹). Therefore, polymer-derived SiAlBCN ceramics as sensing materials, which possess outstanding stability and oxidation/corrosion resistance, have great potential for in-situ monitoring of extreme environmental temperatures in the future.