2007 Volume 47 Issue 1 Pages 16-24
The equilibrium relation of Ti and O dissolved in liquid iron saturated with solid titanium oxides was measured in the temperature range of 1 823 to 1 923 K. Pure Ti2O3 (s) phase was identified as the equilibrium deoxidation product for iron melts containing 0.25-4.75 mass% Ti. Using Wagner's formalism, the present results were thermodynamically analyzed to determine the equilibrium constant of Ti deoxidation reaction for the formation of pure Ti2O3 (s) and the first- and second-order interaction parameters between Ti and O given as follows in the temperature range of 1 823 to 1 923 K.
2Ti+3O=Ti2O3 (s) (0.25<mass% Ti<4.75)
eOTi=−1642/T+0.3358, eTiO=−4 915/T+1.005
The equilibrium titanium oxide phase was identified as Ti3O5 (s) for iron melts containing 0.0012-0.25 mass% Ti at 1 873 K. The equilibrium constant of Ti deoxidation reaction for the formation of pure Ti3O5 (s) were estimated as follows.
3Ti+5O=Ti3O5 (s) (0.0012<mass% Ti<0.25)
The activity coefficient of Ti in liquid iron at infinite dilution, γ°Ti(s) was assessed as 0.011, 0.014 and 0.018 at 1 823 K, 1 873 K and 1 923 K, respectively.