Equilibrium between titanium and oxygen in liquid Fe-Ti alloy coexisted with titanium oxides at 1873K

Abstract

The equilibrium between Ti and O has been investigated in molten Fe-Ti alloy saturated with various kinds of titanium oxides at 1 873 K. The present results have been thermodynamically analyzed applying Wagner's formalism as well as Darken's quadratic formalism with the excess Gibbs free energy change of mixing described by Redlich-Kister type polynomial. The equilibrium constants and the interaction parameters of Wagner's formalism were given as follows at 1 873 K in the present work. Ti2O3(s)=2Ti+3O (0.5 <6.2) log K=-10.17, eoTi=-0.34 ′Ti3O5′(s)=3Ti+5O (0.0004 <0.36) log K=-16.86, eoTi=-0.34 The Henry constant of Ti in liquid Fe-Ti alloy was assessed as follows at 1 873 K. γ Ti(l)o=0.0090 The interaction parameters of Redlich-Kister type polynomial for molten Fe-Ti-O alloy were given by the following values at 1 873 K in the present work. 0ΩFe-Ti=-73360/J 0ΩTi-O=-1035900/J The estimated results based on Wagner's formalism as well as Darken's quadratic formalism polynomials were well agreed with the experimental results which were observed between Ti and O equilibrium contents in molten Fe-Ti alloy. © 2006 ISIJ.