| 摘要 |
PURPOSE:To achieve improved response and durability by cladding thin and porous platinum and rhodium layers on a surface of a solid electrolyte of a detection gas side electrode. CONSTITUTION:A platinum electrode 4 is formed at inside/reference gas side of a solid electrolyte substrate 3, on the other hand particles 5 such as a stabilization zirconia, etc., are sealed to outside/detection gas side, and then a porous detection electrode 6 is formed on the surface by a platinum layer 6a and a rhodium layer 6b. Therefore, a detection gas can reach the substrate 3 rapidly and a high response can be obtained over a long period of time by cladding of rhodium. In this case. for forming the electrodes 4.6, first a platinum layer is formed on platinum by chemical plating, then heat treatment is performed at a temperature of 950-1550 deg.C, for allowing platinum to be shrunk, and then the layer becomes a porous platinum layer 6a where holes are dissipated. Then, rhodium is deposited on the electrode 6a by chemical plating. Further, a porous protection layer 7 is adhered by plasma flame spraying for preventing deterioration of the electrode 6. |
