Wettability under Non-Reactive and Reactive Conditions in the Systems Ni/YSZ and Ni/Ti-TiO2/YSZ

The wetting properties and interfacial reactions for the systems Ni/YSZ and Ni/Ti-TiO2/YSZ were studied at 1500°C. In a purified Ar-4v/oH2 atmosphere no reaction took place between the metallic and the ceramic phases and measurements of the contact angle between molten metals and ceramic showed no wettability, θ>90°. The lowest contact angle, compared to that corresponding to the Ni/YSZ system (117°), was achieved for the system Ni/YSZ(TiO2) (103°). At 1500°C and in the presence of a carbon potential in the furnace atmosphere an interaction was observed to occur at the metal-ceramic interface, caused by the carbon dissolved in the metallic melt. The extent of such an interaction depended on time and the carbon potential in the gas phase and influenced the wetting properties of the systems, leading to better wetting conditions as the interaction extent increased.