Thermodynamics of Nickel Aluminate Formation in Molten Nickel

Abstract

AbstractAs part of an ongoing program of the study of oxidation and deoxidation reactions in nickel alloy melts, experiments were performed to determine the oxygen solubility in molten nickel in equilibrium with alumina and nickel aluminate in the temperature range 1733–1873 K. Experiments were conducted at the University of Toronto with nickel of initial low oxygen content while those at the University of Kyoto were with initial high oxygen content. The results show very good agreement. Both sets of results were combined to show the effect of temperature on the reaction under investigation as follows:Ni(l)+O +Al2O3(s) = NiO. Al2O3(s);∆G0=(−188,840±16,700)+(82.8±9.3)T J mol−1.The oxygen potential of the melt corresponding to the three phase equilibrium was measured by means of a disposable oxygen probe and the results were utilized to redetermine the free energy of dissolution of oxygen gas in liquid nickel in the temperature range 1733–1873 K, which is given as:1/2 O2(g) = O(Ni)(1 wt%), ∆G0 = −102,420+19...