Étude de la mouillabilité des particules granulaires par les alliages d'aluminium durant la filtration d'aluminium /

Abstract

SUMMARYThis thesis was undertaken to study the wetting between granular media (alumina) and Al-Mg alloys. The objective was to develop a test method to characterize different granular alumina particles and differentiate one from the other by using the wettability concept. Two types of experimental methods were used to measure the wetting: sessile drop and infiltration methods.The sessile drop system constructed is one of the few, if not the only one, available in Canada in which the contact angle measurements can be carried out with a liquid metal drop injected directly onto the solid surface. However, the results indicated that this method is not appropriate to differentiate different granular alumina particles due to prevention, by the rough surface, of the droplets taking their proper form.Using the infiltration system, various alumina particles were tested. The data obtained from these tests were analyzed using three capillary models based on: (i) an energy balance with an average pore size, (ii) an energy balance with a pore size distribution, and (iii) a force balance with periodically changing pore radius. The two models based on the energy balance were developed especially for infiltration experiments, and the third one was taken from the literature. The results were consistent and showed that it was possible to differentiate different alumina samples with the infiltration method. The reactions taking VI place between Al-Mg alloys and different alumina particles were also investigated by using the infiltration technique. SEM and TEM analyses showed that spinel was formed independent of the experiment duration and the type of alumina particles used in the experiments at 1000 K under argon atmosphere. The theraiodynamic analysis indicated the same tendency.