Ceramic-metal interaction and wetting phenomena in the B₄C/Cu system

The experimental study of the wetting phenomena in the boron carbide-copper system, using the sessile drop method at 1150°C shows that molten Cu attacks boron carbide substrates forming a crater below the contact area. Boron additions prevent crater formation, improve wetting and, for a 10 at.% B alloy, reduce the equilibrium wetting angle to 40°. Thermodynamic analysis of the Cu-B-C system in the Cu-rich corner confirms the experimental results. These results and similar ones obtained in the TiC-Cu system suggest that the presence of a carbide phase over a concentration range is a key feature that governs wetting phenomena and chemical interaction at these metal-carbide interfaces.