A. Tsoga

Wettability and interfacial reactions in the systems NiYSZ and Ni/Ti-TiO2/YSZ

In order to minimise the interfacial energy between metal and ceramic in the SOFC NiYSZ cermet anode, the wetting properties and interfacial reactions for the systems NiYSZ and NiTiTiO2YSZ were studied in the temperature range 1250–1500°C. In purified Ar-4 vol.% H2 atmosphere no reaction takes place between the metallic and the ceramic phase and measurements of the contact angle between molten metals and ceramic at 1500°C showed no wettability, θ > 90°. The lowest contact angle, compared to that corresponding to the NiYSZ system (117°), was achieved for the system NiYSZ (TiO2), (103°). At 1500°C and in the presence of carbon 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 depends on time and carbon potential in the gas phase and influences the wetting properties of the systems, leading to better wetting conditions as the interaction extent increases.

Surface and grain-boundary energies in yttria-stabilized zirconia (YSZ-8 mol%)

AbstractThe multiphase equilibration technique has been used to measure the equilibrium angles that develop at the interphase boundaries of a solid-liquid-vapour system after annealing and also the surface (γsv)and the grain-boundary, (γss) energies of polycrystalline yttria-stabilized zirconia (8 mol% Y2O3). The data was recorded in the temperature range 1573–1873 K. Linear temperature functions were obtained for the surface energy

Correlation between the oxidation state of α-SiC and its wettability with non-reactive (Sn) or reactive (Ni) metallic components and their binary Si-alloys

\gamma _{SV} (Jm^{ - 2} ) = 1.927 - 0.428x10^{ - 3} T

Modified YSZ/Ni structures with improved stability

and for the grain-boundary energy

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

\gamma _{SS} (Jm^{ - 2} ) = 1.215 - 0.358x10^{ - 3} T