Nanostructured aluminium titanate (Al2TiO5) particles and nanofibers: Synthesis and mechanism of microstructural evolution

Abstract

In this study, aluminium titanate (AT) particles and nanofibers were synthesized through citrate sol gel and sol gel-assisted electrospinning methods in both nanostructured powder and nanofiber forms. The results of X-ray diffraction analysis, field-emission scanning electron microscopy and differential thermal analysis showed that the synthetic products benefit a nanostructured nature with a grain size less than 70nm. The optimal values for time and temperature at which a roughly pure AT is attained were determined as 2h and 900°C, respectively. It was found that the sol gel precursor bears an amorphous structure till 700°C and begins to be crystallized to alumina, anatase and AT at higher temperatures. Moreover, AT tends to decompose into rutile and alumina at temperatures higher than 900°C and its degradation rate reaches a maximum at temperatures near to 1100°C. In this synthesis, citric acid was used as a chelating agent for Al3+ and Ti4+ ions and it was shown that a low citric acid-to-metal cation ratio leads to larger numbers of nuclei during crystallization and smaller grain size. Finally, a model was suggested to describe the microstructural evolution of AT compound based on a nucleation and growth regime.