Metal-ceramic microstructure control in partial reduction reactions in the model system FeMnO by doping

The formation of metal-ceramic multi-phase microstructures by partial reduction of ternary or higher ceramic oxides was investigated experimentally in the model system FeMnO by changing the oxygen partial pressure at constant temperature and total pressure. The addition of dopants such as BaO, CaO, MgO, SrO, Al2O3, Cr2O3 or ZrO2 to the initial, polycrystalline oxide solid solution (Fe1−xMnx)1−ΔO strongly influences the location of metal precipitation during reduction. Electron microscopic studies were performed for microstructural characterization, phase identification and chemical analysis. The experimental observations are discussed based on solubility limits and the segregation of dopants.