Corrosion effects of glass on YSZ electrolytes

This work reports on the microstructure and electrical properties of differ ent yttria stabilized zirconia (YSZ) based cells using: (i) intimate mixtur es of YSZ and a commercial soda-lime glass (up to 20 wt%), sintered at diff erent temperatures; (ii) YSZ disks covered with a layer of glass on one sid e and fired in a clean laboratory furnace for two hours at different temper atures (1250-1350 degrees C); (iii) YSZ pellets exposed to the exhaust gase s of one (industrial) glass melting furnace, at temperatures around 1300 de grees C. Microstructural observations and impedance spectroscopy measuremen ts were used to demonstrate the potential of the latter technique in monito ring the electrolyte corrosion. The high-and intermediate-frequency impedan ce arcs showed a significant and coherent dependence on the progress of cor rosion, due to the formation of glass-ceramic composites,with large glass/c eramic interfaces. Similar results were obtained with laboratory scale and industrial experiments. EDS analysis showed an higher concentration of Y2O3 in the intergrain region and a corresponding concentration decrease in the electrolyte grains. (C) 1999 Elsevier Science Limited. All rights reserved .