Craig & Antonelli
Oxygen sensor ceramic and process for preparing the same
 Oxygen sensor ceramic of solid electrolyte of zirconia-yttria system comprises aggregates of cubic zirconia grains having an average grain size of 2-10 .mu.m and monoclinic zirconia grains having an average grain size of 0.2-1 .mu.m, the appregates of the cubic zirconia grains being in contact with one another, and the monoclinic zirconia grains being distributed as aggregates in clearances among the aggregates of the cubic zirconia grains, and has a high thermal shock resistance, a high mechanical strength and a resistivity equal to that of the ceramic consisting only of cubic zirconia grains. The oxygen sensor ceramic is prepared by mixing zirconia powder having a grain size of 0.1-0.5 .mu.m with 4-8% by mole of yttria powder having an average grain size of 0.5-5 .mu.m, on the basis of total mixture, and molding and firing the mixture at 1,400.degree.-1,550.degree. C. 
Hitachi, Ltd.
H Y C Y G
H01M Y02E C04B Y02P G01N
inventional additional inventional additional inventional
Takeo Tadahiko
Yamazaki Miyoshi