Preparation of Films for Solid Oxide Fuel Cells by Center-Injection Low Pressure Plasma Spraying

Abstract

Abstract A new plasma spray process was developed for the rapid deposition of very dense electrolyte layers for solid oxide fuel cells (SOFCs). The dense yttria-stabilized zirconia (YSZ) film was prepared by a center-injection low pressure plasma spraying (CI-VPS) process on various substrates in a triple-torch reactor. For deposition on porous substrates, an intermediate layer was applied using conventional atmospheric plasma spraying (APS) to close the large pores in the substrate. The films were characterized by XRD, SEM, and EMPA. The porosity of the film was analyzed by computerized image analysis of the micrographs. The film was also fractured by four-point bending to characterize the nature of bonding of layer-to-layer and within the deposit. The film analysis showed that YSZ layers with porosities of 0.3 % could be obtained at very high deposition rates with the CI-VPS process, with a very good functional performance of the layer as an electrolyte. Building of a complete SOFC by successive deposition of an atmospheric pressure sprayed porous cermet film, the dense YSZ electrolyte layer, and a porous perovskite film is discussed.