Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés
J. Phys. IV France 03 (1993) C7-1007-C7-1011
Microstructure and interfaces of a reaction coating on aluminium alloys by laser processingX.B. ZHOU and J.Th.M. DE HOSSON
Department of Applied Physics, Materials Science Centre, University of Groningen, Nijenborgh 4, 9742 AG Groningen, The Netherlands
This paper reports an approach to coat a ceramic layer on aluminium alloys by means of chemical reaction. The reaction product of Al2O3 layer of 100 µm in thickness has been formed using a powder mixture of silicon oxide and aluminium by laser processing. It turns out that the large amount of heat from the exothermic reaction has a predominate effects on the formation of the oxide layer. Further, the negative free energy of the reaction may promote the metal/oxide wetting. The micro-hardness and wear tests proved that the oxide layer is hard and strong. A mullite intermediate layer between aluminium and oxide have been identified by TEM. The atomic structure and defects of the reaction layer have been imaged at high resolution electron microscope.
© EDP Sciences 1993