In slagging coal-gasifier systems, the combination of oxides present as impurities in coal and combustion temperatures that can exceed 1650 degreesC restrict the use of liner materials in the coal combustion chambers to refractories. In this study, the slag-refractory interactions of a new high chrome sesquioxide refractory was characterized. High-temperature cup tests showed that the molten oxides infused into the refractory and that the sesquioxide refractory reacts with the oxides in a manner similar to spinel phase refractories. Studies of the coal slag's individual oxide components showed CaO reacts with the chrome refractory to form a low melting Ca(CrO2)(2). FeO reacts with the sesquioxide to form a interface layer of (Cr,Fe)(3)O-4 spinel phase. Results of this study now make it possible to design studies for improving corrosion resistance to increase refractory life.