Synergistic microstructural and chemical engineering: A novel strategy for constructing robust piezoresistive films in extreme environments

Precise monitoring in extreme aerodynamic environments requires sensing materials with high thermal endurance. However, the application of traditional metal oxide sensing films is often limited by coupled microstructural and chemical degradation driven by thermodynamic and kinetic instabilities. In this work, alumina-reinforced indium tin oxide (ITO-Al₂O₃) composite films are developed via standard Micro-Electromechanical Systems (MEMS) processes. The modified films exhibit improved electrical stability and piezoresistive performance at elevated temperatures up to 900 °C, with a reduced resistance drift rate of 0.001%/h. Microstructural characterization indicates that this enhancement is associated with the formation of a core-shell structure, which mitigates detrimental degradation pathways like grain growth, defect evolution, and elemental diffusion in pristine ITO films, thereby improving their structural, chemical, and electrical stability at elevated temperatures. These results demonstrate the feasibility of tailoring thermally stable sensing films via composite engineering, providing a promising approach for the development of robust sensing devices for next-generation aerospace and energy applications.