APPLICATION OF WETTING THEORY TO NON-REACTIVE LIQUID METAL-GRAPHITE SYSTEMS

An attempt has been made to correlate the published contact angle data for graphite-liquid metal systems with the theory of liquid-solid wetting phenomena. To establish the reasonableness of the approach, the potential expression for dispersion interaction was employed for mercury, and the magnitude of the contribution from dispersion forces to the liquid surface energy of mercury, γLd, was calculated to be 193 erg/cm2. This compares favourably with the published experimental value of 200 erg/cm2. Similarly the γLd values for liquid metals of known contact angle with graphite were calculated and subsequently substituted in a modified Young equation in order to calculate the respective values of Φ. The parameter, Φ, has been defined by Girifalco and Good as the ratio of adhesion and cohesion forces for any two phases in contact. The calculated values of Φ were observed to rise to a maximum for all metals in the same periodic group as carbon, which would be predicted for chemically similar" phases. © 1969 Chapman and Hall."