Wetting in nonreactive liquid metal-oxide systems

Pure metal/oxide interfacial energies are characterized by weak Van der Waals and electronic interactions. The intrinsic contact angles in these systems are larger than 90 degrees. The roughness of the ceramic increases the apparent contact angle and may lead to the formation of composite surfaces that are not fully penetrated by the metal. Oxygen dissolved in the metal adsorbs at the liquid metal/vapor and the liquid metal/ceramic interfaces, leading to improved wetting with contact angles as low as 70 degrees. Statistical thermodynamic models of the interfaces are in good agreement with the experimental adsorption isotherms. The combination of a metallic ternary addition and dissolved oxygen offers the potential for increased wetting, but the identification of suitable additions remains elusive. Increases in temperature lead to modest decreases in contact angle, and do not appear to be a practical route to improved wetting in nonreactive systems.