| Early empirical publications on metal foam production have shown that ceramic particles are required in the alloy in order to produce stable aluminum foams. Following a commonly accepted theory, it is believed that the wetting behaviour of the alloy on the particles is the main factor causing the stabilizing effect of the particles. The connection between wetting and metal foamability, however, has not yet been proven. The present work is a systematic study of the wetting behaviour of synthetic aluminum alloys on ceramic substrates under high vacuum conditions rounded off by foaming tests with several of these alloy/ceramic particle systems.;Based on analyses of wetting experiments, it was found that certain alloying elements can reduce the contact angle of aluminum on Al2O 3 and SiC, and that even wetting systems that are commonly considered non-reactive are in fact highly affected by chemical reactions occurring at the interface.;The foaming results showed that while it appears that the stabilization theory linking wetting behaviour and foam quality is generally correct, wetting experiments under idealized (almost oxygen-free) conditions are unsuitable to predict foam stability based on these models, as in-situ wetting behaviour during foaming seems to be significantly different from that observed during the wetting experiments.;The wetting experiments were conducted in a horizontal tube furnace, which allows for high precision contact angle measurements; foaming tests were carried out in an expandometer. From the wetting behaviour and accompanying foam expansion and quality results, the common foam stabilization theory was evaluated. |
