Microstructural effects on the electrical and mechanical properties of Ni–YSZ cermet for SOFC anode

The electrical and mechanical properties of Ni–YSZ cermet as the anode support of solid oxide fuel cell (SOFC) are determined by the metallic and ceramic components, respectively. We used YSZ and NiO commercial powders of the average particle size from 1 to 10 μm to fabricate Ni–YSZ cermets with different microstructures. The porosity of the cermets was also modified by the amount of carbon black addition. The distribution of each phase of cermets was analyzed with scanning electron microscopy combined with energy dispersive spectroscopy. The electrical conductivity and fracture strength of the Ni–YSZ cermets were investigated and interpreted in a view of percolation phenomena. The finer particles, either NiO or YSZ, were interlinked well by sintering and the electrical and mechanical properties of Ni–YSZ cermets were enhanced by the percolation of Ni and YSZ, respectively.