Using the zero-creep technique for small-diameter wires and measurements of the dihedral angle at the base of thermally-etched grain-boundary grooves, absolute values of the surface energy and grain-boundary energy were found for cobalt at 1455C in a pure helium atmosphere. The surface energy was 2595mJ/m2 and the grain-boundary energy was 1010mJ/m2.

The Surface and Grain Boundary Energies of Iron, Cobalt and Nickel. T.A.Roth: Materials Science and Engineering, 1975, 18[2], 183-92