Sol-Gel-Free Electrospinning of α‑Al₂O₃ Suspensions: A Systematic Study on Processing Commercial Powders into Ceramic...

This study optimizes the fabrication of electrospun α-Al₂O₃ ceramic fibers from commercial powders, focusing on the synergy between solid loading (α-Al₂O₃ solid oxide), solvent systems (water/alcohol), and surfactant (PVP) molecular weight (K15 and K30) for suspension elaboration. Rheological characterization identified a highly suitable processing window with consistency indices (K) of 3.85-4.85 Pa·s and pseudoplastic flow (n) ranging from 0.927-0.972 for the elaborated suspensions. The dominant viscoelastic liquid character (G'> G"), high electrical conductivity (up to 1825 μS/cm), and reduced surface tension (58-64 mN/m) facilitated stable Taylor cone formation and enhanced jet thinning. A breakthrough was achieved by increasing solid loading and transitioning to high-molecular-weight PVP K-30. This strategy, coupled with isopropanol-based solvents, provided steric stabilization and structural recovery necessary to maintain single-fiber integrity during both spinning and sintering at 1500 °C. The resulting fibers exhibited high micrometric uniformity and morphological retention despite the formation of intermediate aluminum oxycarbides. This research demonstrates a robust, cost-effective, and scalable route for designing advanced ceramic scaffolds directly from industrial precursors.