Ti Deoxidation Equilibrium in Molten Fe–Ni Alloys at Temperatures between 1823 to 1923 K

Equilibrium between Ti and O in Molten Fe–Ni, Fe–Cr and Fe–Cr–Ni Alloys Equilibrated with ‘Ti3O5’ Solid Solution

“…In previous researches, equilibrium between Ti and O in molten Fe-Ni, Fe-Cr and Fe-Cr-Ni alloys at 1823 K to 1923 K were investigated to control the deoxidation products in these alloys. 1,2) As the result, it was confirmed by EBSD distinction that Ti deoxidation product in molten FeNi alloy was 'Ti3O5' and that in molten Fe-Cr and Fe-CrNi alloys changed from Ti2O3 to 'Ti3O5' with decrease of Ti content in the alloys. Also, solubility of Fe, Cr and/or Ni in 'Ti3O5' phase were confirmed in low Ti content region in the alloys.…”

“…1,2) Deoxidation of Fe-Ni, Fe-Cr and FeCr-Ni alloys with titanium were carried out in a 'Ti3O5' crucible by induction furnace to fix the activity of titanium oxide and to avoid contamination of those alloys with the © 2011 ISIJ other crucible material. The samples were quenched by turning off the power of the furnace and impinging helium gas on the surface of the melt after the predetermined equilibrium time.…”

“…Also, solubility of Fe, Cr and/or Ni in 'Ti3O5' phase were confirmed in low Ti content region in the alloys. It was assumed in previous reports 1,2) that the activity of Ti3O5 was unity when the solubility of Fe, Cr and Ni oxides in 'Ti3O5' phase were lower than (XFe+XCr+XNi)/ XTi(in 'Ti3O5' solid solution)=0.05. Only the experimental data that satisfy this condition were used for thermodynamic analysis by Redlich-Kister type polynomial.…”

A Phenomenological Investigation on the Control of Oxides at the Interface Using an Electrochemical Cell

“…To maintain a clean interface without oxide inclusions and also to decompose already exiting oxide inclusions, the oxygen concentration at the interface must be maintained below the thermodynamic equilibrium oxygen concentration dependent upon the specific deoxidizer such as Al or Ti. According to many previous researches, [14][15][16][17][18][19][20][21][22] the maximum value of soluble oxygen con- centration without oxide precipitation is below 6 ppm. Thus in the present work, the interfacial oxygen concentration of less than 3 ppm with an external direct current of 0.1 A should inhibit and decompose oxides.…”

“…[14][15][16][17][18][19][20][21][22] However, recent work by Suito et al [23][24][25] suggest the existence of a super-saturation phenomenon required for aluminum oxide formation in molten steel at 1 873 K and defined the ratio between the super-saturation concentration and the equilibrium concentration as the critical super-saturation ratio. Due to the necessity of an excess driving potential, aluminum oxide formation in the bulk Fe-Al-O alloy is somewhat difficult even though the bulk oxygen is above the thermodynamic equilibrium concentration.…”