Mechanochemical assisted synthesis and powder characteristics of nanostructure ceramic of α-Al 2O 3 at room temperature

Abstract

In this study, α-Al 2O 3 was synthesized mechanochemically by milling a mixture of hematite (Fe 2O 3) and aluminum (Al) as reagents using a planetary ball mill at room temperature. The powder samples were characterized by commonly used bulk techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM) and high resolution transmission electron microscope (HR-TEM), differential thermal analysis (DTA), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Fourier transform infra-red spectroscopy (FTIR). Experimental results showed that the mechanochemical reaction proceeds with an increase in milling time and has been completed by 2 h. Also, it was found that increasing the milling time can effectively decrease the nanocrystalline size and increase the lattice strain of α-Al 2O 3. Finally, the grains of the milled powders were comparatively angular consisting of submicron fragments which appear to have been welded together, forming larger agglomerates.