Activity Measurement of FeO•Cr₂O₃ in ‘FeO•(Cr, Al)₂O₃’ Solid Solution

抄録

Thermodynamic information on the equilibrium between dissolved Cr and O in steel melt is the basic knowledge to control Cr content in the stainless steel production process. In the case of using alumina refractories, molten Fe–Cr alloy equilibrates locally with ‘FeO•(Cr, Al)₂O₃’ solid solution at the interface between the melt and refractories when Cr content in the alloy is low. Wide composition range of ‘FeO•(Cr, Al)₂O₃’ solid solution is known, and the activity data of FeO•Cr₂O₃ in ‘FeO•(Cr, Al)₂O₃’ solid solution is required to precisely estimate and control the Cr–O equilibrium relation in molten Fe–Cr when the alloy is produced in the furnace lining by Al₂O₃ refractories. In the present work, crucibles made of ‘FeO•(Cr, Al)₂O₃’ solid solution were equilibrated with molten Ag under CO–CO₂ gas mixture at 1873 K to determine the activity of FeO•Cr₂O₃ in the solid solution.