Deoxidation Equilibrium of Chromium in Liquid Iron-Nickel Alloys

Abstract

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 (g°O (Fe) ϭ0.0105; g°O (Ni) ϭ0.357), 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 Ϫ7% Cr (pure iron) to Ϫ1.7 % 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.

Thermodynamics of Oxygen Solutions in Carbon-Containing Fe-Ni Alloys

“…If the melt base contains two or more components (in our case, iron and nickel), the content of the element at which the minimum of the oxygen solubility curve is observed also depends on the affinity of this element for the metals of the melt base. Our previous thermodynamic analysis and experimental studies of the oxygen solubility in Fe-Ni-R melts (R = Mn, Cr, V, Ti, Al) showed that the [2,5]), as in the case of carbon, with an increase in the nickel content of the melt, which is determined by the interaction of all components of the melt with one another. The strengths of the bonds of the components with one another in the melt are characterized by the interaction parameters.…”

“…For silicon, The calculated equilibrium constants for reaction (1) at different nickel contents of the melt at 1873 K are presented in Table 1 and Fig. 1 in comparison with the data on oxygen solutions in Fe-Ni melts containing Mn [1,4], Cr [2], V [2], Si [1,4], Ti [2], and Al [2,5].…”

“…The thermodynamics of oxygen solutions in Fe-Ni melts containing Mn, Si, Al, Cr, V, and Ti has been studied in sufficient detail [1][2][3][4][5]. However, no information is available on oxygen solubility in carbon-containing Fe-Ni melts.…”

THERMODYNAMICS OF OXYGEN SOLUTIONS IN ALUMINUM-CONTAINING Ni – Cr MELTS

“…При содержании в жидком никеле хрома приблизительно 2 % наблюдается минимум на кривой растворимости кислорода, дальнейшее повышение содержания хрома приводит к повышению растворимости кислорода [1]. При раскислении жидкого никеля хромом продуктом реакции при содержании хрома выше 0,01 % является оксид хрома Cr 2 O 3 [2]:…”

“…Концентрация кислорода в расплаве, равновесная с заданным содержанием хрома, может быть рассчита-на по уравнению (2) где - параметр взаимодействия первого порядка; -параметр взаимодействия второго порядка при выраже-нии концентрации компонентов в массовых процентах.…”