Preparation of Long Alumina Fibers in Aqueous Solution Using Oxalic Acid and Aluminum Nitrate

Long alumina fibers with 60 cm in length were prepared by sol-gel method. The spinning sol was obtained by mixing aluminum nitrate, oxalic acid, and polyvinylpyrrolidone with a mass ratio of 10∶3∶2. Fourier transform infrared （FTIR） spectra, X-ray diffraction （XRD）, and scanning electron microscopy （SEM） were used to characterize the properties of the gel and ceramic fibers. The fibers with uniform diameter and smooth surface were obtained by sintering at 1 200 ℃ for 1 h, and their main phase was indentified as α-Al2O3.