Investigation of the thermodynamic properties of Cu-Ni alloys obtained by electrodeposition or by casting

The enthalpies of alloy formation in the copper-nickel system have been determined by reaction calorimetry of dissolution at 298 K and it has been shown that this method can be applied for the investigation of electrodeposited alloys, which often are irreversible and representing metastable systems. It has been demonstrated that electrochemical Cu-Ni plating from diphosphate electrolyte under conditions leading to a deposition of a solid copper-nickel solution allows it to produce a thermochemical analogue of a cast alloy. The results obtained indicate that a model of the subregular solution type still provides a reasonable description of the thermodynamic functions in this system. The activity of the components over the entire concentration range was calculated using experimental data and the relationship between partial enthalpy of mixing and partial excess entropy of dissolved components in infinitely dilute solutions.