International Journal of Modern Physics C Vol. 15, No. 5 (2004) 675–687 c  World Scientific Publishing Company THERMODYNAMIC CALCULATION OF n-COMPONENT EUTECTIC MIXTURES L. BRUNET ∗ and J. CAILLARD Giat Industries, 7 route de Guerry Bourges Cedex, F-18023, France ∗ l.brunet@giat-industries.fr P. ANDR ´ E L.A.E.P.T, Universit´ e Blaise Pascal 24 avenue des Landais, Aubiere, F-63177, France Received 5 November 2003 Revised 12 January 2004 This paper presents a simple numerical method to calculate the eutectic mixture compo- sition and melting temperature. Using a Newton–Raphson method to solve the nonlinear problem, the calculation is possible for n-component eutectic. We tested this algorithm on inorganic and organic mixtures. A better correlation between experimental and nu- merical results has been found for organic compound. Keywords : Eutectic; thermodynamic; phase change. 1. Symbols G Gibbs free enthalpy (J/mol/K) μ Chemical potential R Ideal gas constant (8,314510 J/mol/K) H ◦ Enthalpy of fusion (J/mol) T Temperature (K) x Molar fraction a Activity (J/mol) n Number of components S Entropy (J/mol/K) ◦ Standard property 2. Thermodynamical Problem A lot of progress has been made in the calculation of thermodynamic properties of complex mixtures. 1,2 Solid mixtures are used in a wide variety of industrial pro- cesses. Solid mixtures can be made of several organic or inorganic components. The 675