Thermodynamics of Titanium and Oxygen Dissolved in Liquid Iron Equilibrated with Titanium Oxides

• Published in: ISIJ International Vol. 47; no. 1; pp. 16 - 24
• Main Authors: Pak, Jong-Jin, Jo, Jong-Oh, Kim, Sun-In, Kim, Wan-Yi, Chung, Tae-In, Seo, Seok-Min, Park, Joo-Hyun, Kim, Dong-Sik
• Format: Journal Article
• Language: English
• Published: Tokyo The Iron and Steel Institute of Japan 2007; Iron and Steel Institute of Japan
• Subjects: Applied sciences; deoxidation; equilibrium constant; Exact sciences and technology; interaction parameter; liquid iron; Metals. Metallurgy; oxygen; titanium; titanium oxides; Thermodynamics; Iron oxide; Liquid oxygen; titanium oxides; titanium; deoxidation; interaction parameter; Titanium oxide; equilibrium constant; liquid iron; oxygen
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.47.16

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) log KTi2O3=44238/T−13.0 eOTi=−1642/T+0.3358, eTiO=−4 915/T+1.005 rOTi=0.0385, rTiO=−0.355 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) log KTi3O5=72813/T−21.32 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.