MICROWAVE SINTERING OF ZIRCONIA-YTTRIA ELECTROLYTES AND MEASUREMENT OF THEIR IONIC-CONDUCTIVITY

Yttria-zirconia electrolytes of 3 and 8 mol% Y2O3 nominal content have been prepared by sintering in a microwave furnace under several diffe rent conditions to obtain crack-free high density specimens. The ionic conductivity of both compositions has been investigated with a four-p robe DC technique as a function of temperature over the 400 degrees-10 00 degrees C range and as a function of time at the normal fuel cell o perating temperature of 1000 degrees C. Impedance spectroscopy has bee n used to separate the grain boundary contribution to the total resist ivity. The results have been compared with conventionally sintered (ra diant heat) materials.