Carbon, oxygen and chromium solubility surface in liquid copper

Thermodynamic modeling of phase equilibria in the liquid metal of Cu-C-O and Cu-Cr-C-O systems was done for the temperature range 1100-1300 °С. Thermodynamic analysis of interaction processes in the investigated systems was performed using the method of constructing of the components’ solubility surface in the metal melt. Such diagram allows connecting the compositions of the metal melt with the type of products of interaction, including solid particles of oxides, components of oxide melt and gaseous reaction products. Temperature dependences of the equilibrium constants of the reactions, which are taking place in the copper melt of the investigated systems, was clarified during thermodynamic modeling. The first order interaction parameters (Wagner) of elements in the liquid copper were evaluated during simulation. The thermodynamic modeling results are presented in the form of graphs on which the compositions of the metallic melt (depending on the temperature) are reflected. On these graphs metal melt compositions are in equilibrium with one or another interaction product. Based on the results of the simulation, it was determined that the formation of copper oxide particles in the presence of carbon and chromium dissolved in liquid copper is thermodynamically unlikely. Using graphite as a deoxidizing element, it is necessary to take into account the low solubility of carbon in liquid copper.