Microstructural Design of Sensor Materials Using the Core-shell Concept

An yttria stabilised zirconia which exhibits a coreshell microstructure was investigated as a method to produce a zirconia with high ionic conductivity and improved thermal shock resistance. Zirconia grains consist of an outer shell of tetragonal zirconia with an inner core of monoclinic phase zirconia. Impedance spectroscopy was used to identify the e€ect of processing conditions on the grain boundary and grain interior ionic conductivity. At optimised processing conditions the grain boundary conductivity was found to be signi®cantly higher than conventional yttria stabilised zirconia. A small improvement in thermal shock resistance of the material was also observed. # 1998 Elsevier Science Limited. All