Wetting phenomena on external and internal interfaces in solids: common features and peculiarities

Abstract

At the critical point of the β-γ' transition in a Sn-rich Sn-In alloy a discontinuity in the thermal dependence of the tin-indium interdiffusion coefficient has been observed. Similar, but shifted in temperature discontinuities have been observed during In diffusion along grain boundaries in tin and Sn-Ge interphase boundaries. The results obtained are explainable under the assumption that the prewetting phase transition occurs on the boundaries. Penetration of Zn along symmetrical [100] tilt grain boundaries in Fe-5at%Si and Fe-12at%Si alloys has been studied. Wetting of grain boundaries by the Zn-rich melt has been observed. The region behind the wetting film is observed to have an unusually high grain boundary diffusivity of Zn followed by the region of usual grain boundary diffusivity. Such a phenomenon may be explained in terms of the so-called premelting phase transition “GB-thin wetting film on the boundary”. Grain boundary phase diagrams have been constructed.