The wetting of some solid transition metals by liquid lithium, sodium, and potassium

Abstract

Spontaneous wetting of plane, rigid surfaces resulting solely from surface forces is shown to occur only in those systems in which advancing angles of zero are observed. Contact angles were measured for 12 solid metal-liquid metal systems consisting of a transition metal and an alkali metal. In the temperature range up to 250º, zero advancing angles were observed for the systems Cu-Li, Sa-Hg, Ag-Se, Au-Na, Pt-Ka, Pd-Na, Zn-Na, Ag-K, Zn-K. In the same temperature range, only non-zero advancing angles could be obtained for the systems Cu-Na, Ni-Na, and Cu-K. The reason for the non-wetting in the latter three systems is discussed in terms of two alternative models, one based on the degree of misfit at the solid-liquid interface, and the other on the stability of oxides on the solid metal surface. These alternative explanations probably have a common origin.