Role of nano-size TiO2 particles on the crystallite size of microwave-Combustion synthesized Al2O3/TiC composite

The main goal of the current study is to clarify the effect of TiO2 particles size (micro and nano) on the crystallite size of microwave-combustion synthesized Al2O3/TiC composite. Al, C, both nano- and micron TiO2 have been mixed mechanically and milled using a planetary ball mill. The milled samples have been pressed before exposing to microwave with different powers. In order to validate the formation of Al2O3 and TiC phases, the samples have been analyzed by X-ray diffraction. Crystallite sizes of produced TiC and Al2O3 in samples containing micron TiO2 are about 46.6-87.9 and 63.8-208.8 nm respectively and in samples containing nano-TiO2 are about 38.2-68.7 and 54.4-99.5 nm respectively. It means that using nano-TiO2 as one of the raw materials leads to formation of nano-structure Al2O3/TiC composite. Microstructure of produced composites has been evaluated using a scanning electron microscope (SEM). Microscopic evaluations show that Al2O3 phase in micron samples has a regular shape, unlike needle shape in nano-samples. (C) 2010 Elsevier B.V. All rights reserved.