Abstract
Different compositions of pure magnesium aluminate spinel, alumina-spinel and magnesia-spinel Nano ceramic materials were prepared using co-precipitation and sol-gel techniques. The powders prepared from different molecular compositions of the starting materials; 1 : 1, 1 : 4 and 4 : 1 of either magnesium nitrate and aluminum nitrate (co-precipitation) or magnesium chloride and aluminum hydroxide (sol-gel) were calcined at different firing temperatures; 900, 1100, 1300 and 1500 degrees C. The solid phase compositions of the calcined samples were investigated using x-ray diffraction analysis (XRD). The crystal size of the fired powders was calculated from XRD patterns using Scherer's equation. The microstructure and solid phase analysis of some selected samples were investigated using scanning electron microscope attached with energy dispersed x-ray unit. Based on the mineralogical, crystal size and microstructure studies, it is concluded that different compositions of pure spinel, magnesia-spinel and alumina-spinel could be attained at different firing temperatures; 900 degrees C, 1100 degrees C, 1300 degrees C and 1500 degrees C via co-precipitation and sol-gel techniques. For economical reasons firing at 900 degrees C is considered sufficient for obtaining pure spinel, magnesia-spinel and alumina-spinel Nano powders (<100 nm); particles prepared via sol-gel are relatively smaller compared with those prepared via co-precipitation.