OXYGEN ADSORPTION ISOTHERMS AT THE SURFACES OF LIQUID Cu AND Au-Cu ALLOYS AND THEIR INTERFACES WITH A1203 DETECTED BY WETTING EXPERIMENTS

摘要

The wetting of Cu-O and Au-Cu-O alloys on alumina single-crystals and the surface free energy of these liquids have been determined as a function of oxygen activity. The explored oxygen activity range is from 10~(-10) to the value corresponding to the formation of the mixed oxide AlCuO_2. The oxygen adsorption at the surface of a metallic liquid and its interface with an oxide are shown to mainly depend on the external phases in contact with the liquid (vapour or oxide respectively). The free energies of the surfaces show monotonic decreases with log α_o above a critical value of α_o.