Wettability of SiC by aluminium and Al-Si alloys

Abstract

The variations with time of the contact angle formed by molten pure aluminium or Al-Si alloys with single crystalline SiC were measured by the sessile drop method in a vacuum of 10⁻⁴ to 10⁻⁵ Pa at temperatures ranging from 933 to 1200 K. In the Al/SiC system, a “non-wetting-wetting” transition was observed at a temperature that decreases as time increases. After holding times of about 2 h, contact angles were stabilized to acute angles even at the aluminium melting point. Although additions of silicon to aluminium were in such amounts as to prevent Al₄C₃ formation at the interface, wettability in both pure Al/SiC and Al-Si alloys/SiC systems was not observed to differ appreciably.