Sintering behavior of Ni/Y2O3-ZrO2 cermet electrodes of solid oxide fuel cells

The sintering behavior of Ni/Y2O3-ZrO2 (YSZ) cermet electrode coating on 3 mol% Y2O3-ZrO2 electrolyte was studied under moist and dry hydrogen atmosphere at 1000degreesC for up to 2000 h. The sintering behavior of Ni/YSZ cermet electrodes was dominated by the agglomeration and grain growth of Ni particles in the cermets, which was critically related to the content of Ni and YSZ phases in the cermet. For pure Ni electrode coating, the sintering was substantial and cross plane cracks and isolated Ni island were formed after sintering at 1000degreesC for only 250 h. However with the addition of YSZ phase, the sintering of Ni/YSZ cermet anode coatings was significantly reduced. For the cermet composition of Ni (50 vol%)/YSZ (50 vol%), the change in the surface porosity and pore size distribution after sintering at 1000degreesC for 2000 h was very small. The microstructural stability of the Ni (50 vol%)/YSZ (50 vol%) cermet electrodes was also demonstrated by the performance stability tested under current load of 250 mAcm(-2) at 1000degreesC for over 2500 h. (C) 2003 Kluwer Academic Publishers.