Development of 8YSZ electrolyte of SOFC by the suspension flame spray

This study is to create a high density 8YSZ electrolyte of solid oxide fuel cell by the suspension flame spray. Dense zirconia coating couldn’t be achieved by the flame spray due to its lower flame temperature. Introducing the suspension method to prepare feedstock could overcome the problem of flow ability of nano powder. The feedstock slurry of various viscosities with deionized water, polyethylene glycol (PEG) and 8YSZ powder which particle size is 200 nm. The dense electrolyte coating was deposited on the anode by flame spraying. By changing the parameters, the higher density of 8YSZ electrolyte would be achieved. The results show that with higher viscosity of the suspension, the density of the layer increases. As the stand-off distance increases, the porosity of coating increases as well due to the decreasing of kinetic energy. Surface speed of spraying affects residual thermal stress and resulted in some cracks in the coating when surface speed decreases. The microstructures images show the flat and dense surface of the coating. From the XRD pattern can find that the phase of 8YSZ coating is the same as raw powder. This study successfully develops high density and thin 8YSZ electrolyte coating by low temperature flame spraying.