1989 Volume 30 Issue 2 Pages 137-145
As the wettability of solid oxides by liquid metals gives important information on the development of composite materials, metal- ceramics joinings, and the behaviour of deoxidation products in liquid metal, a large number of papers have been published. However, there are large discrepancies among the values reported.
In this work, the wettabilities of solid oxides (Al2O3, MgO, CaO, ZrO2, and SiO2) by liquid pure metals (Sn, Ag, Au, and Cu) have been measured over a wide temperature range by the sessile drop method.
Main results obtained are as follows:
(1) Surface tensions of pure liquid metals can be expressed by the following equations:
γSn=551−0.09[T(K)−505],
γAg=910−0.17[T(K)−1234]
γAu=1105−0.28[T(K)−1336]
γCu=1320−0.28[T(K)−1356]
(2) Contact angles and work of adhesions between liquid pure metals and solid oxides were closely related to the standard free energy change of formation of oxides. Values of contact angle and work of adhesion changed linearly with temperature and in some systems refracted points were observed at the temperatures which corresponded to the refracted points in the free energy-temperature diagram.
(3) The wettability of solid oxides by liquid metals depended not only on the stability of solid oxides which can be expressed by the standard free energy change of oxide formation but also on ionic radii of metals which compose oxides.
