Abstract
In order to discuss the formation of MnS–CuS0.5 inclusion in γ-Fe, the phase diagram of the MnS–CuS0.5 binary system has been determined by using a confocal scanning laser microscope (CSLM) and a chemical equilibration technique. In addition, the activities of MnS and CuS0.5 in the liquid phase at 1473 K were investigated by chemical equilibration with molten Cu. The phase diagram of the binary system was found to be of a eutectic type with mutual solid solubility between MnS and CuS0.5. The activities of MnS and CuS0.5 showed positive deviation from the ideality. Finally, the solid steel composition equilibrated with the inclusion was estimated by using the determined thermodynamic properties.
