| abstract |
PURPOSE:To obtain a reference electrode having a superior response property of electromotive fore, stability and reproducibility, by using a mixture of Cr powder and Cr2O3 powder and making a ratio of these materials and its packing quantity at a prescribed value and carrying out the pretreatment. CONSTITUTION:An oxygen probe consists of a mullite tube 1, a ZrO2-9%MgO tube 2 as a solid electrolyte, a Cr/Cr2O3 refernce electrode 3, an Al2O3 powder 4, an Al2O3 cement 5 and an Mo wire 6 connected with Cr/Cr2O3. When Cr2O3 of a Cr/Cr2O3 mixing ratio is <=3%, capacity as a Cr/Cr2O3 is lost and also, when Cr2O3 of the Cr/Cr2O3 mixing ratio is >=20%, reaction of oxygen with Cr is delayed and stable action is not shown. Further, shrinkage by heat is avoided by sintering the mixture at >=1,550 deg.C. 0.1-0.3g packing quantity is suitable with relation to a response property. |