Fabrication of finely structured silicon-supported SOFC with anode deposited by multi-phase plasma spraying

The mechanically mixed NiO/YSZ powder was usually used as the anode material of atmospheric plasma sprayed (APS) solid oxide fuel cells (SOFC). Big particles and the non-uniform distribution of the pores were observed in the resultant anode layer. To overcome the limitations, a method of fabricating anode layer by multi-phase plasma spraying (MPS) was proposed in this paper. The NiO and YSZ powders were delivered into plasma jet by a separate injection, where nitrogen carrier was employed to feed micrometer-sized NiO powder and liquid carrier was to feed submicrometer-sized YSZ powder. Suspension plasma spraying (SPS) was applied to fabricate dense electrolyte layer. The microstructure and composition of coatings were characterized by SEM and EDS. The results showed that finely structured anode layer with small particle size (d ∼ 2 μm) was achieved by the MPS method. The MPS anode layer was porous with the porosity of 32.1% while the APS anode layer was 22.6%. Three kinds of elements (Ni, Y, Zr) were observed in the MPS anode layer and the NiO content was calculated to be 49.6 wt%. In the SPS process, the suspension flow rate was matched to the plasma gas flow rate to obtain proper injection condition.