Experimental study of phase equilibria in the MnO-Si-2-"TiO2"-"Ti2O3" system

Abstract

Phase equilibria and liquidus surface in the system MnO-SiO2-"TiO2"-"Ti2O3" under controlled atmosphere have been investigated in the temperature range from 1200 to 1 500 degrees C and in the range of log PO2 from -7.6 (pCO/pCO(2)=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 primary phases have been observed; molten oxide, manganosite (MnO), ru-tile (TiO2-delta), tridymite and cristobalite (SiO2), tephroite (Mn2SiO4), rhodonite (MnSiO3), spinel (Mn2TiO4-MnTiO4), pyrophanite (MnTiO3-Ti2O3) and pseudobrookite ("MnTi2O5"-Ti3O5) solid solutions. By decreasing oxygen partial pressure, homogeneous liquid oxide area becomes smaller. No ternary compounds or ternary solid solutions were observed.