Evaluation of interaction parameters in metallic solutions by the isoactivity method

Abstract

The evaluation of interaction parameters of elements from isoactivity data is theoretically analyzed. Normally, the Wagner formalism is limited in the evaluation of interaction parameters from isoactivity data because the condition of constant activity reduces the degrees of freedom of the studied system. The consistency and discrepancy between the logarithm formula and solubility equation are discussed. In theory, x i ϭ 2N i in M-i-j melts under the isoactivity of i becomes the critical condition of consistency and discrepancy between the logarithm formula and solubility equation. Experimental results show that a discrepancy exists between the two methods if experimental data do not meet the condition of x i Յ 2N i . It is necessary to consider the possibility of the formation of compounds as x i Ͼ 2N i in the system M-i-j at isoactivity of i.