Thermodynamics of Oxygen Solutions in Ni–Cr Melts Containing Aluminum

Abstract

The influence of aluminum on the solubility of oxygen in Ni–Cr melts is considered on the basis of thermodynamic analysis. Very low aluminum concentrations have practically no influence on the oxygen concentration in the melt, which is determined by the chromium content. When the aluminum content exceeds 0.01%, it determines the solubility of oxygen in the melt, in all cases. The minimum oxygen concentration corresponds to about 0.2% Al. With increase in chromium content in the melt, the minimum oxygen concentration increases. It is 2 × 10^–3%, 7 × 10^–3%, and 10^–2% for nickel alloys with 10%, 20%, and 30% Cr, respectively.