Crystal growth in manganese-doped magnesium oxide powders

Abstract

The crystallite size of pure and Mn-doped MgO has been measured after calcination at different temperatures in oxidizing and reducing atmospheres. The oxidation state and location of the impurity ions was assessed by e.s.r. techniques. Manganese has a negligible effect on growth of the oxide fired in a reducing atmosphere, but the increase in crystallite size is marked under oxidizing conditions. This enhanced growth is evident at about 900°C and the magnitude of the effect is much greater than that found in vacuum calcines. Crystallite growth mechanisms of Mn-doped MgO under these differing calcination conditions are proposed.