Solubility of Carbon in Molten Copper-Nickel Alloy and Vickers Hardness of Copper-Nickel-Saturated Carbon

A Cu-Ni alloy in which the nickel content was included up to approximately 5 mass% was melted in a graphite crucible with a high frequency induction furnace to prepare the Cu-Ni-C-sat (saturated carbon) alloy. Solubility of carbon into Cu-Ni alloy increased with the nickel content and with the melting temperature. The relation between the activity coefficient of carbon for Cu-Ni-C-sat and the temperature could be expressed by numerical formulas. This work proposed that the interaction parameter, omega(Ni)(C), for Cu-Ni-C-sat was -16.1. The precipitated particles from the melt were graphite. Vickers hardness of Cu-Ni-C-sat system increased with C content. The Cu-Ni-C-sat alloy prepared in this study was hardened by precipitation hardening of the graphite particles and solution hardening of Ni.