WETTABILITY OF ALUMINIUM WITH ALUMINIUM CARBIDE (GRAPHITE) IN ALUMINIUM FILTRATION

摘要

Graphite filters have previously been employed based on petrol coke. Wetting between molten aluminium and graphite is studied. Al_3C_4 is formed at the interface between aluminium and graphite. In filtration of aluminium inclusions such as Al_3C_4 formed in the hall electrolysis are removed. Wetting between aluminium and Al_3C_4 (graphite) is determined in kinetic studies in the higher temperature range 1000-1200-. The results are extrapolated down to temperatures employed in the industry around 700-. The contact angle between aluminium and graphite decreases with time. It may be divided into three stages: removal of an oxide layer on aluminium, formation of Al_3C_4 at the interface, finally giving an equilibrium value for Al-Al_3C_4. This value is found to be around 126° at 700-.