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

Abstract

The Ti deoxidation equilibrium of Fe–Ni, Fe–Cr and Fe–Cr–Ni alloys saturated with ‘Ti₃O₅’ and Ti₂O₃ phase was clarified in previous researches. Solubility of Fe, Cr and/or Ni oxides in ‘Ti₃O₅’ phase equilibrated with liquid Fe–Ni, Fe–Cr and Fe–Cr–Ni alloys at 1823 K to 1923 K were measured by SEM–EDS. It was confirmed that the solubility of Fe, Cr and/or Ni oxide in ‘Ti₃O₅’ phase at low Ti content increase with decrease of Ti content in alloys. Titanium content that dissolution of Fe, Cr and/or Ni oxide into ‘Ti₃O₅’ phase becomes apparent increases with increase of Cr and/or Ni content of the alloys.
The activity of Ti deoxidation product, ‘Ti₃O₅’ phase, equilibrated with Fe–Ni, Fe–Cr and Fe–Cr–Ni alloys was also evaluated by Redlich-Kister type polynomial. Equilibrium between Ti and O at low Ti content of those alloys was analyzed using the activity of ‘Ti₃O₅’ phase.