Surface properties of Ag-Cu-Zr liquid alloys in relation to the wettability of boride ceramics

The wetting phenomena and adhesion between Ag-Cu-Zr molten alloys (where Zr is an active brazing element) and ZrB2-ceramic substrate have been investigated from theoretical and experimental point of view. The wetting phenomena of molten alloy/ceramic substrate depend on the bonding characteristics of liquid alloys and ceramics as well as the magnitude of interactive forces at the interface. Accordingly, the first step of this investigation is to determine the surface properties of Ag-Cu, Ag-Zr and Cu-Zr liquid alloys. The energetics of the bulk and the surface of liquid alloys have been analysed in the framework of statistical mechanical theory in conjunction with Quasi-Lattice Theory (QLT), through the study of the concentration dependence of various properties such as surface tension, surface composition, concentration fluctuations in the long wavelength limit and Warren-Cowley chemical short-range order parameter. Combining the Young and the Dupre equations, the obtained values of surface, tension together with contact angle data have been used to calculate the work of adhesion.