Breaking the Temperature Barrier: Ultra‐Stable SiHfBCN Ceramic Coatings for High‐Temperature Pressure Sensing

Pressure sensors are essential for acquiring real‐time information that directly influences the performance and safety of modern engine control systems. However, developing pressure sensors that can operate reliably at high temperatures remains a formidable challenge due to the lack of stable sensing materials. Here, we report a novel polymer‐derived SiHfBCN ceramic coating exhibiting outstanding pressure‐sensing behavior and remarkable thermal stability at elevated temperatures. The SiHfBCN coating was fabricated on sapphire substrates through a preceramic polymer route and subsequently pyrolyzed at various temperatures up to 1500 °C. The amorphous ceramic film features a nanodomain structure composed of amorphous SiHfBCN and crystalline HfC(N) nanoparticles together with in situ forms carbon ribbons, which provide excellent electrical and mechanical stability. The optimized coating demonstrates a high gauge factor K of up to 42.000, excellent repeatability, and stable signal response under cyclic compression, maintaining its performance up to 1300 °C. These results highlight the potential of SiHfBCN ceramics as next‐generation materials for high‐temperature pressure‐sensing applications.