A. Candel-Ruiz, A. Killinger, University of Stuttgart, Germany, Stuttgart, Germany; R. Gadow, Universität Stuttgart, Stuttgart, Germany; H. Weckmann, DLR e.V., Stuttgart, Germany
Thermal spray processes represent a cost effective and flexible method for the production of functional coatings by using metallurgic, cermetic and ceramic materials. Due to the high kinetic energy of the impinging particles, the HVOF (High Velocity Oxygen Fuel) technique is able to produce extremely dense coatings with very low porosity. In this study, several yttria stabilized zirconia (YSZ) powders have been sprayed by HVOF for the fabrication of electrolyte layers applied in SOFC (Solid Oxide Fuel Cells) applications. Coatings were characterized regarding their porosity, leak tightness and electrochemical properties and results are compared to VPS sprayed coatings. The electrochemical behavior of the cells sprayed with the optimized set of parameters was determined applying U(i)-characteristics and impedance spectroscopy. With the destination thickness of about 40 µm, competitive leak tightness could be established.
Thermal spray processes represent a cost effective and flexible solution for the production of functional coatings by using metallurgic, cermetic and ceramic materials. Due to the high kinetic energy of the impinging particles, the HVOF (High Velocity Oxygen Fuel) technique is able to produce extremely dense coatings which can substitute the sintered SOFC electrolyte layers. Appropriate substrates and optimized robot trajectories for the minimization of temperature gradients during the coating process have to be considered.
Results presented in this paper show that HVOF can be a cost efficient alternative for SOFC electrolyte fabrication.
