Solution Precursor Plasma Spray (SPPS) of Ni-YSZ SOFC Anode Coatings

摘要

Although the deposition of Ni-YSZ anodes by conventionalplasma spray is more successful than other SOFC components,the large NiO and YSZ particles used for the spray process,about 50-150 microns for high porosity coating deposition,reduce the density of three phase sites for electrode reaction.In this paper, the solution precursor plasma spraying (DCSPPS)process, in which solution precursors of the desiredresultant materials are fed into a DC plasma jet by atomizinggas, was used to synthesize and deposit porous Ni-YSZcomposite anodes. The deposition results show that severalprocess parameters have significant effects on themicrostructure and phase composition of the depositedmaterial. The deposits were composed of tower-like,irregularly shaped agglomerates and splats. The sizes of theagglomerates increase with the decrease of the plasma torchpower and most are not completely molten during the impact.The amount of splats is proportional to the power and they aremuch smaller than the agglomerates in volume. After heattreatment to reduce the NiO present in the as depositedcoatings, the coatings were found to contain small sphericalYSZ particles about 0.5 micrometers in diameter distributed ina continuous Ni matrix. The coatings have 29%-51% porositydepending on the process parameters.