Electrospinning preparation and microstructure characterization of homogeneous diphasic mullite ceramic nanofibers

In this work, diphasic mullite (3Al(2)O(3)center dot 2SiO(2)) nanofibers with good homogeneity were prepared by electro-spinning method. Aluminum nitrate (AN) and aluminum isopropoxide (AIP) were used as alumina sources, commercial colloidal silica as silica source, and polyvinyl alcohol (PVA) as polymer additive. Precursor nanofibers with continuous and uniform structures were acquired at mass ratio of PVA to precursor sol from 0.06 to 0.09. gamma-Al2O3 phase was obtained at 878 degrees C and mullite phase formed at 1322 degrees C upon heating of the precursor under air atmosphere. Calcined samples suggested mullite as dominant phase at 1300 degrees C and amorphous SiO2 could even exist at 1400 degrees C. As-prepared nanofibers possessed continuous structures with subequal average diameters at 900-1200 degrees C. However, such morphological characteristics were lost at temperatures above 1300 degrees C due to rapid growth of crystal grains. Al and Si elements were uniformly distributed in fibers and mixed at nanoscale, confirming homogeneity and diphasic features of nanofibers.