Experimental study of phase equilibria in the MnO-"TiO 2"-"Ti2O3" system

Abstract

Phase equilibria and liquidus in the system MnO-"TiO 2"-"Ti2O3" under controlled atmosphere have been investigated in the temperature range from 1 300 to 1550°C and in the range of log pO2 (in atm) from -7.2 (pCO/pCO2=1) to -16.6 (C-CO equilibration). High-temperature equilibration, quenching and electron probe microanalysis (EPMA) were employed to obtain equilibrium compositions of liquid and several solid solutions. The following phases have been observed; molten oxide, manganosite (MnO (s.s.)), rutile (TiO2-δ (s.s.)), spinel (Mn2TiO 4-MnTi2O4), pyrophanite ("MnTiO 3-Ti2O3) and pseudobrookite ("MnTi 2O5"-Ti3O5) solid solutions. Liquidus of manganosite and rutile were measured and compared with previous investigations. "MnTi205" compound was confirmed to be unstable phase in the MnO- "TiO2" system. It was found in the present study that sub-solidus phase equilibria are affected considerably by oxygen partial pressure. © 2005 ISIJ.