Development and microstructure optimization of atmospheric plasma-sprayed NiO/YSZ anode coatings for SOFCs

In this paper, preparation and characterization of porous anode layers with uniform phase distribution are discussed for solid oxide fuel cell (SOFC) application. The Ni/8YSZ cermet coatings were fabricated by atmospheric plasma spray (APS) process using oxidized nickel coated graphite (Ni-graphite) and 8 mol% yittria — stabilized zirconia (8YSZ) blend as feedstock. To control the microstructure of the coating, the nickel coated graphite with low density was used as a starting feedstock instead of conventional pure nickel (Ni) powder. To balance the conductivity, uniform porosity, and structural stability of the coatings, the effects of process parameters such as hydrogen gas flow rate, stand off distance and pore formation precursor (graphite) addition on the microstructures of the resulting coatings are investigated. The results show that the anode coatings with high conductivity, structural stability and porosity could be deposited with moderate hydrogen gas flow rate and short stand off distance.