Abstract

The effect of carbide alloying elements such as chromium and tin upon the bonding state and the interfacial carbon/copper zone in a copper melt have been investigated. The reactivity behaviour, contact angle and the kinetics of wettability have been investigated for each system studied (C/Cu, C/Cu–Sn, C/Cu–Cr and C/Cu–Sn–Cr) using Auger electron spectroscopy and line profile/sessile drop experiments performed under ultra high vacuum conditions. Non-wetting systems such as C/Cu and C/Cu–Sn are characterised by (i) an adhesive solid–solid bond strength and van der Waals interactions and (ii) monotonous behaviour during experiments where the kinetics are controlled by the viscous flow of the liquid drop over the solid substrate. Wetting systems such as C/Cu–Cr and C/Cu–Sn–Cr show a completely different behaviour. For these two systems, chromium tends to segregate at the reinforcement/metal interface, forming a stable carbide compound. Chromium segregation and carbide formation processes lead to different kinetics of wettability which can be summarised in a three step process.