INFLUENCE OF INTERFACIAL REACTION-RATES ON THE WETTING DRIVING-FORCE IN METAL CERAMIC SYSTEMS/

The wetting of copper-silicon alloys of various compositions on vitreo us carbon substrates at 1423 K was studied by the sessile drop method. The morphology and chemistry of products of interfacial reactions bet ween silicon and carbon were characterized by scanning electron micros copy (SEM), electron probe microanalysis, and high-resolution optical profilometry. In addition to measurements of contact angles and spread ing kinetics in the reactive Cu-Si/Cv system, similar measurements wer e performed for the nonreactive Cu-Si/SiC system. It was found that th e reaction rate has no effect on the final contact angle, which is nea rly equal to the thermodynamic contact angle of the alloy on the react ion product. These findings appear to be valid for a wide range of int erfacial reaction rates and for different types of interfacial reactio ns.