The oxygen-wetting transition in metal/oxide systems

For a non-reactive metal/oxide system, when the partial pressure of oxygen in the furnace, PO2, is increased progressively, the contact angle ? hardly varies up to a threshold value PO2t at which a decrease of ? is initiated. The experimental data on the O2-wetting transition in metal/oxide systems are discussed by means of a statistical thermodynamic model of adsorption at metal/vapour and metal/oxide interfaces developed previously for binary solutions. An equation is established allowing the PO2t value of a metal/oxide couple to be calculated from known values of thermodynamic properties of mixing of liquid metal-oxygen bulk solutions.