THERMODYNAMICS OF THE OXYGEN SOLUTIONS IN SILICON-CONTAINING Ni–Co MELTS

Abstract

Thermodynamic analysis of oxygen solutions in silicon-containing Ni – Co melts has been carried out. The equilibrium constant of interaction of silicon and oxygen dissolved in the nickel-cobalt melts, the activity coefficients at infinite dilution, and the interaction parameters characterizing these solutions were determined for melts of different composition. The dependences of the oxygen solubility on the contents of cobalt and silicon in the studied melts were calculated. With increasing cobalt content in melt deoxidation ability of silicon decreases. In Ni – Co alloys containing more than 20 % of cobalt, when the silicon content is less than 0.2 %, deoxidizing ability of silicon is almost the same. At silicon content more than 2 %, the higher is cobalt content in alloys, the more is decrease in deoxidizing ability of silicon.