Deoxidation Equilibrium of Chromium in Liquid Iron-Nickel Alloys

抄録

Thermodynamic analysis of oxygen solutions in iron-nickel melts with chromium has been carried out. Since the bond strength of oxygen with such a melt becomes weaker with an increase in the nickel concentration (γ°_O(Fe)=0.0105; γ°_O(Ni)=0.357), the deoxidation power of the chromium in liquid nickel is higher than that in iron melt.
The deoxidation power of chromium remains almost constant when the nickel concentration in melt increases to 20% but it rises sharply with a further increase in its content. Oxygen solubility curves pass through a minimum, which shifts to lower chromium contents in a range of from -7% Cr (pure iron) to -1.7% Cr (pure nickel) when the nickel concentration rises. Minimum oxygen concentrations in nickel are lower almost by an order of magnitude as compared to iron. Subsequent chromium additions cause an increase in the oxygen concentration in melt; in this case, the higher the nickel content, the sharper the rise in the oxygen concentration after the minimum when chromium is added. Deoxidation of iron-nickel melts with chromium was experimentally studied for the Fe-20%Ni, Fe-40%Ni and Fe-60%Ni alloys. Experimental and calculated results are in good agreement.