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 experim entally in the model system Fe-Mn-O by changing the oxygen partial pre ssure at constant temperature and total pressure. The addition of dopa nts such as BaO, CaO, MgO, SrO, Al2O3, Cr2O3 or ZrO2 to the initial, p olycrystalline oxide solid solution (Fe1-xMnx)(1-Delta)O strongly infl uences the location of metal precipitation during reduction. Electron microscopic studies were performed for microstructural characterizatio n, phase identification and chemical analysis. The experimental observ ations are discussed based on solubility limits and the segregation of dopants.