Controlling grain growth in electrospun ZrO2 nanofibers: The role of biphasic precursor systems

Abstract Zirconia nanofibers frequently suffer from undesirable phase transformations and abnormal grain growth at elevated temperatures, significantly limiting their high-temperature applications. To overcome these challenges, we developed an innovative biphasic precursor system that combines zirconium acetate and zirconium oxychloride as co-precursors. By precisely optimizing the molar ratio of these precursors, we successfully fabricated high-quality yttria-stabilized zirconia (YSZ) nanofibers through a combination of electrospinning and sol-gel processing. Extensive characterization (FTIR, STA/TG-MS, XRD, SEM, and TEM) revealed that the optimal precursor ratio of 8:2 (zirconium acetate: zirconium oxychloride) effectively suppresses grain growth while maintaining smooth, defect-free fiber surfaces with uniform diameter distribution. The resulting nanofibers calcined at 700 °C exhibited outstanding mechanical properties, including superior tensile strength (0.25 ± 0.02 MPa) and minimal bending stiffness (23 ± 2 mN). At 1000 °C, these nanofibers maintain structural integrity with improved strength retention (0.18 ± 0.01 MPa) and controlled grain growth, while preserving cubic phase stability. The biphasic precursor strategy enables precise control over crystallization kinetics and effectively suppresses detrimental phase transformations. This study not only addresses the critical issue of thermal instability in zirconia nanofibers but also provides new insights into precursor selection for the design of high-performance ceramic nanofibers.