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J. Phys. IV France
Volume 113, January 2004
Page(s) 101 - 104

J. Phys. IV France
113 (2004) 101
DOI: 10.1051/jp4:20040022

Chemical behaviour of iron base substrates in liquid Mg-Zn alloys

J.C. Viala, D. Pierre, F. Bosselet, M. Peronnet and J. Bouix

Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Université Lyon I, 69622 Villeurbanne Cedex, France

The chemical reactivity between solid iron base substrates and magnesium melts containing zinc has been investigated at 1000 K. Characterization by OM, SEM and EPMA of the interfacial zones formed after 65h heating in a magnesium melt with 7.7 wt% of zinc added revealed a strong bonding between the iron substrates and the light alloy. Indications were obtained for the occurrence of some dissolution-recrystallization at the solid/liquid interface. A 8-10  $\mu$m thick $\alpha$Fe(Al,Si) reaction layer was observed to have formed at the substrates surface but zinc was not detected in this reaction layer. Thermodynamic considerations based on chemical activities are developed to account for that a priori surprising chemical behaviour.

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