Model for Surface Tension of Pure Liquid Metals: Revisit to Iida’s Model

In the present study, a well-known Iida’s equation for surface tension was modified to improve the predictivity of the surface tension of pure liquid metals. A semi-empirical equation for the surface tensions (\({\sigma }_{m}\)) of liquid metal at its melting temperature proposed by Iida et al. uses a generalized \(\alpha \) value of 0.51 to represent the ratio of the distance required to separate one atomic pair from its equilibrium distance. This study improved the predictability of the equation by refining the \(\alpha \) value using the equilibrium interatomic distance (\({r}_{e}\)) and atomic radius (\({r}_{a}\)). Assigning an accurate \(\alpha \) value for each element greatly improves the prediction accuracy of the surface tension for liquid metals. Furthermore, the critical temperature (\({T}_{c}\)) was calculated based on the interatomic distance (\({r}_{c}\)) at \({T}_{c}\) and temperature coefficient of density (\(d{\rho }_{T}\)/\(dT\)) and used to predict the temperature dependence coefficient of surface tension (\(d{\sigma }_{T}\)/\(dT\)). As results, more accurate surface tensions of 42 liquid metals were predicted over the entire liquid state temperature.

Graphical Abstract