In-situ formed amorphous carbon layer: Enabling excellent mechanical performance in Al/Y co-doped ZrO2 nanofibers

Traditional zirconia (ZrO 2 ) fibers suffer from severe limitations in mechanical performance under extreme conditions due to high-temperature phase transformation-induced cracking, abnormal grain growth, and inherent brittleness, making it difficult to meet the stringent requirements of fields such as aerospace and energy systems. This work proposes an innovative fabrication strategy that successfully achieves in-situ growth of an amorphous carbon coating layer on the surface of Al/Y co-doped ZrO 2 nanofibers through electrospinning and hot-stretching processes. In this work, zirconium acetate acts as both zirconium source and solvent, simplifying precursor preparation. The hot-stretching process utilizes the micropores on the fiber surface to form an in-situ amorphous carbon layer, which significantly enhances the mechanical properties of the fibers: tensile strength reaches 8.08 MPa, and the fiber membrane maintains structural integrity after 500 bending cycles at 80% strain, demonstrating excellent fatigue resistance and elastic recovery capability; it also exhibits outstanding thermal shock resistance at extremely low (-196°C) and ultra-high (1350°C) temperatures. Through the key innovation of introducing an amorphous carbon layer via hot-stretching, this work successfully integrates high strength, superior flexibility, and outstanding fatigue resistance into ZrO 2 fibers. Furthermore, owing to its high porosity (92%), the fiber membrane exhibits ultra-low thermal conductivity and effective sound absorption. Ultimately, this provides a reliable solution for multifunctional ceramic fiber materials applied in high-temperature environments (up to 800°C).