Complete wetting of helium on graphite

Using the vibrating-wire microbalance technique we have found that superfluid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, normal fluid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ all wet graphite completely. Incomplete wetting above $T_{\lambda }$ was simulated by intentionally introducing a temperature gradient in the apparatus. Data in the thick-film regime are found to be consistent with the Frenkel-Halsey-Hill model of adsorption. The graphite fiber surface has been characterized through volumetric adsorption isotherms, revealing additional surface area not previously accounted for by others using this technique.