| 摘要 |
PURPOSE:To keep the initial characteristics of the detector inscribed on the face stably for a long time by using a precious metal electrode that contains a specific quantity of fine powder of metal oxide for the electrode in the exhaust gas side. CONSTITUTION:Alumina porcelain powder the particle diameter of which is 0.1mu or less is mixed in a precious metal compound aqueous solution such as platinum chloride aqueous soltion and is stirred. The obtained suspension is applied to the outside of a one-side-sealed pipe-shaped ion conductive solid electrolyte porcelain, and is thermally decomposed at high temperature to make the quantity of alumina porcelain powder contained in the platinum electrode as the external electrode 5.0% up to 30.0% by weight. The internal electrode is installed as before, and is made contact with air as a reference, the external electrode is made contact with exhaust gas, ultrapower caused by the difference between both oxygen partial pressures is sensed to detect the quantity of oxygen in the exhaust gas. The external electrode is not corroded because the porcelain powder is present althrough the electrode is exposed in a high temperature exhaust gas, the initial characteristics can stably be maintained for a long time. |
