Doping of alumina ceramics by manganese - thermodynamical and experimental approach

The preparation of a transparent ultra-fine-grained doped ceramics requires homogeneous dopant distribution in matrix. In the present work, two thermodynamical phenomena allowing such (the dissolution and formation undesirable secondary phases) were experimentally theoretically studied. A general thermodynamic-kinetic model was developed for dissolution, which verified experimental conditions used this work. experiment showed that Mn3O4 with overall concentration 1 at.% particle size 50 nm is dissolved homogenized fine-grained alumina matrix within less than one hour at temperature 1220 ?C. For purposes study undesired phase, phase diagram Al2O3-Mn3O4 system calculated using CALPHAD approach. Detailed STEM observations combined EDX EELS chemical analyses data calculation need some modifications because they overestimate solubility Mn underestimate MnAl2O4 spinel.