Rapid mechanically activated solid-state synthesis of nanocrystalline α-Al2O3 using Fe2O3 and Al

Abstract

In this research, we demonstrate rapid mechanochemical synthesis of nanocrystalline α-alumina (α-Al 2 O 3 ) from a starting mixture of hematite (Fe 2 O 3 ) and aluminum (Al). The formation of α-Al 2 O 3 nanocrystallites occurs during the solid-state reaction and through the reduction treatment. Also in this paper, effects of milling time on the particle size and lattice strain of nanocrystalline α-Al 2 O 3 are investigated. The results indicate that complete reduction is reached only after 2 h of milling in a planetary mill and the crystallite size of obtained α-Al 2 O 3 is in general about 12 nm. Also, it is found that increasing the milling time can effectively decrease the nanocrystalline size and increase the lattice strain of α-Al 2 O 3 . Finally, the experimental results show appropriate homogeneity and dispersion of related nanocrystallites.

Crystalline Microstructure of Corundum Fillers Determined from Powder X-Ray Diffraction Patterns

“…Some papers present more complete characterisation based on XRD patterns including mean crystallite size and strain (e.g. [8][9][10][11]), crystallite size distribution [12], and rarely crystallite size and shape distributions [13]. Densification and re-crystallisation can be achieved by overgrinding of nanocrystalline corundum [14] but usually the maximum of frequency of crystallite size distributions migrates to smaller crystallite sizes after milling (e.g.…”