Laser machining of ceramic electrolytes for solid oxide fuel cell applications

Resumen del trabajo presentado a la International Conference on Processing & Manufacturing of Advanced Materials: Processing, Fabrication, Properties, Applications, celebrada en Graz (Austria) del 29 de mayo al 3 de junio de 2016.Laser engraving is being reported as a very suitable technique for achieving cost-efficient production of high-quality ceramic parts. Equipments consisting of infrared, green or ultraviolet laser sources, together with a galvanometric computer-controlled head, are now affordable and more frequently used in industry. Therefore, we have used laser machining to modify the shape and microstructure of ceramic plates for solid oxide electrolytes or gas separation membranes. On the one hand, we have prepared self-supporting thin stabilized zirconia (SZ) ceramic electrolytes. They are carved from a sintered SZ plate to shape a 20 μm thick and 8 mm in diameter central region, surrounded by an unprocessed 150 μm thick supporting zone. These self-supporting ceramic membranes can be used to prepare electrode-supported solid oxide fuel cells that can operate at low temperature, due to the reduced thickness of the electrolyte. On the other hand, we have used pulsed laser ablation to imprint in ceramic electrolytes surface roughness on the level of some microns. In this way, we can increase the electrolyte-electrode contact area and, as a result, to decrease the polarization resistance of the electrochemical cells. In this communication we describe the material preparation procedure by laser machining, as well as the structural, microstructural and mechanical characterization by several physical, spectroscopic and diffraction techniques. Finally, single cells have been also studied by electrochemical impedance spectroscopy to ascertain the improvement in electric resistance caused by the laser machining.Peer Reviewe