The adoption of zirconium deoxide as solid electrolyte at home and abroad for high temp. rapid determining oxygen probe results in a limited measuring range due to electron conduction under low oxygen differential pressure and hole conduction under high oxygen differenlial pressure. This invention takes the solid electrotyte tube of cabetaN-Al2O3 which shows quite faint electron conduction and hole conduction under both cases of high and low oxygen differential pressure to instead the zirconium dioxide, so it overcomes the limitation of existing high temp. determining oxygen technigue and enlarges the range of determining up to 0.001 ppm. Which is a range for superlow oxygen content. The inventer takes calcium ide as the reference electrode to replace molybdenum and molybdenum oxide, and takes metal-ceramic as the return circuit electrode to replace metallic molybdenum, thus to improve the resistance to oxidation and corrosion. Besides, the said invention gives out the optimal ........ |