J. Phys. IV France 113 (2004) 69
Experimental study and modelling of Pb-Bi-Hg systemA. Maitre, J.M. Fiorani, J.C. Gachon and M. Vilasi
Laboratoire de Chimie du Solide Minéral, UMR 7555, Université Henri Poincaré, Bd. des Aiguillettes, BP. 239, 54506 Vandoeuvre les Nancy Cedex, France
As a first step, an experimental study of the Pb-Bi-Hg system was performed from calorimetric, XRD and EPMA measurements. Results indicated the presence of a ternary intermetallic compound i.e. Pb B Hg with a narrow homogeneity domain. This phase decomposes peritectically above 45 C. In a second step, all the experimental phase diagram data collected during the present study in the ternary system and the thermodynamic quantities (enthalpies of mixing and activities) given in the literature mainly for binary borders were taken into account in a thermodynamic modelling which used the CALPHAD (CALculation PHAse Diagram) approach. It appeared that two peritectic invariants exist at 37 and 82 C. Otherwise, the calculation of the isopleth section x(Pb)/x(Bi) = 0.45/0.55 versus mercury content which is especially interesting for nuclear applications, suggested the rapid decrease of liquidus temperature even with minor mercury additions (inferior to 1 wt.%).
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