1. The system Cu-Ni-Zn
Both Ni and Zn are the elements most commonly alloyed with Cu, and the ternary system of Cu-Ni-Zn is one of the basic systems for metals such as copper-nickel alloys, nickel silver and some types of brass and bronze. Although many investigations of the phase equilibria in the Cu-Ni-Zn system have been reported, there was a lack of an overall thermodynamic description of the complete ternary system. The system was evaluated by Chang et al. [79Cha], in which a liquidus projection and an isotherm at 775 ºC were provided mainly based on the work of Yamaguchi and Nakamura [34Yam], and Schramm [35Sch]. Recently, we performed a thermodynamic description of the Cu-Ni-Zn system [03Jia]. In the latter work, the binary thermodynamic assessments done by Mey [92Mey] for the Cu-Ni system, by Kowalski and Spencer [93Kow] for the Cu-Zn system, and by Vassilev et al. [00Vas] for the Ni-Zn system have been basically accepted. However, for the calculation of ternary solid solutions, some binary phases in both Cu-Zn and Ni-Zn systems had to be remodelled.
Very few thermodynamic data have been reported for the Cu-Ni-Zn system. Contrary, phase diagram data are relatively well available except for the Zn-rich side. Thus in the present work we describe experimental studies of 5 Cu-Ni-Zn alloys, containing more than 80 at. % Zn. The results have been used to re-assess the parameters describing the phase equilibria in this ternary system.
2. The system Co-Ni-Zn
Iron-group metals and zinc are industrially important. It has been found also that third element additions (for example Ni) to the galvanizing bathes improve coating quality. Thus, phase equilibria in ternary systems involving these metals (in this case Co-Ni-Zn) are technologically interesting.
Some alloys which constituents are metals of the iron group (Fe, Co, Ni) are attractive because of their magnetic properties also Zn binary and ternary alloys with Co and Ni have been subject of experimental studies by the authors who worked also on thermodynamic descriptions of the binary NiZn [2000Vas] and CoZn systems [2003Vas]. The Co-Ni systems is nearly ideal, thus an estimation of the ternary thermodynamic properties is relatively easy to be done sing pertinent geometrical models. In the same time new phase diagram data have been obtained studying 5 Zn-rich Co-Ni-Zn alloys. A thermodynamic description of this system is now under way and is to be completed in a few months.
References
[34Yam] K. Yamaguchi, K. Nakamura, Bull. Inst. Phys. Chem. Res., Tokyo 13(1934), 89.
[35Sch] J. Schramm, Copper-Nickel-Zinc system, Verlag Konrad Triltsch, Würzburg, 1935; cited in [12].
[79Cha] Y.A. Chang, J.P. Neumann, A. Mikula, D. Goldberg, Phase diagrams and thermodynamic properties of ternary copper-metal systems, International Copper Research Association, Inc. NBS, USA, 1979, p. 620.
[92Mey] S.A. Mey, CALPHAD 16(1992), 255.
[93Kow] M. Kowalski, P.J. Spencer, J. Phase Equilibria 14(1993), 432.
[2000Vas] G.P. Vassilev, T. Gomez-Acebo, J.C. Tedenac, J. Phase Equilibria 21(2000), 287.
[2003Jia] M. Jiang, C.P. Wang, X.J. Liu, I. Ohnuma, R. Kainuma, G.P. Vassilev, K. Ishida, “Thermodynamic calculation of phase equilibria in the Cu-Ni-Zn system”, presented in “International IUPAC Conference on High Temperature Materials Chemistry–XI”, 19-23 May, 2003, Tokyo, Japan, To be published in J. Phys. Chem. Solids.
[2003Vas]: G. P. Vassilev, M. Jiang, Thermodynamic Optimisation of the Co-Zn System, 2003, J. Phase Equilibria (to be published).