Abstract
Although the deposition of Ni-YSZ anodes by plasma conventional 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 desired resultant materials are fed into a DC plasma jet by atomizing gas, was used to synthesize and deposit porous Ni-YSZ composite anodes. The deposition results show that several process parameters have significant effects on the microstructure and phase composition of the deposited material. The deposits were composed of tower-like, irregularly shaped agglomerates and splats. The sizes of the agglomerates increase with the decrease of the plasma torch power and most are not completely molten during the impact. The amount of splats is proportional to the power and they are much smaller than the agglomerates in volume. After heat treatment to reduce the NiO present in the as deposited coatings, the coatings were found to contain small spherical YSZ particles about 0.5 micrometers in diameter distributed in a continuous Ni matrix. The coatings have 29%-51% porosity depending on the process parameters.
