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

摘要

Graphite filters have previously been employed based on petrolrncoke. Wetting between molten aluminium and graphite isrnstudied. Al_3C_4 is formed at the interface between aluminium andrngraphite. In filtration of aluminium inclusions such as Al_3C_4rnformed in the hall electrolysis are removed. Wetting betweenrnaluminium and Al_3C_4 (graphite) is determined in kinetic studiesrnin the higher temperature range 1000-1200℃. The results arernextrapolated down to temperatures employed in the industryrnaround 700℃. The contact angle between aluminium andrngraphite decreases with time. It may be divided into three stages:rnremoval of an oxide layer on aluminium, formation of Al_3C_4 atrnthe interface, finally giving an equilibrium value for Al-Al_3C_4.rnThis value is found to be around 126o at 700℃.