Interfacial Interaction Between Ni and Oxide in SOFC Anodes

The interfacial properties of Ni/oxide were quantitatively evaluated by determining the contact angle of nickel particles on oxide substrates at the operating temperature of solid oxide fuel cells (SOFCs). Nickel was coated on 8 mol% Y 2 O 3 -ZrO 2 (YSZ), 10 mol% Sc 2 O 3 -1 mol% CeO 2 -ZrO 2 (ScSZ), and Ce 0.9 Gd 0.1 O 2-δ (GDC) disks by sputtering. Nickel particles were formed on the substrates by annealing these samples under reducing atmospheres. The wettability of nickel particles was found to be the worst on the YSZ substrates, indicating the lowest bond strength between Ni and YSZ. The contact angle of nickel particles for the samples heat-treated under the humidified atmosphere was smaller than that under the unhumidified atmosphere regardless of the oxide substrate. The presence of water vapor will decrease the surface tension of nickel or increase the surface tension of the oxide substrate.