Ga₂O₃/Al₂O₃ fiber composite for stable electrical conduction in air at 1000 °C with pressure sensing

This study develops a conductive material that remains stable in air at extremely high temperatures. Traditional conductive materials, such as carbon- or metal-based systems, often degrade or oxidize near 1000 °C, which limits their use in harsh environments. To solve this problem, we designed a composite material made of heat-resistant aluminum oxide fibers and a gallium–indium liquid metal. A needle-based method was used to distribute the liquid metal evenly through the fiber network, creating continuous conductive pathways. The material was then tested under high temperatures in air to evaluate its electrical stability and mechanical response. The results show that it maintained stable electrical performance at 1000 °C in air for three hours, with very small resistance changes. After repeated heating and cooling between room temperature and 1000 °C, the resistance remained highly stable. High-temperature treatment also reduced the material’s sensitivity to bending and pressure. Structural analysis indicates that a stable oxide layer formed during heating, while the fiber framework preserved the overall structure. These findings provide a simple and effective strategy for designing flexible conductive materials for high-temperature and harsh-environment applications.