Microstructure and electrical conductivity of 3Y-TZ/Al2O3 composites

Abstract

Various amounts of Al2O3 (0.25, 0.5 and 1.0mol%) were added to tetragonal polycrystalline material (3YTZP), prepared using the hydrothermal crystallization method. The effects of the added amount as well as the sintering temperature on the microstructure and electrical properties of the 3Y-TZP/Al2O3 composites were investigated. The alumina addition was found to affect the microstructure of the 3Y-TZP samples obtained after sintering at 1400 or 1500°C only to a slight extent. The lowest values of the blocking factor, which represents the contribution of grain boundary resistivity to the total resistivity of a polycrystal, were observed for the 3Y-TZP with Al2O3 additions of 0.25 or 0.5mol% at measurement temperatures of 550 and 600 °C. The study proves that the 3Y-TZP/Al2O3 should be taken into consideration as solid electrolyte in the intermediatetemperature solid oxide fuel cells.

Keywords

• zirconia
• grain size
• microstructure
• electrical conductivity
• impedance spectroscopy