| 摘要 |
PURPOSE:To elininate unevnenness of inside electrode by circulating chemical plating liquid in forming the cup-shaped inside electrode of an oxygen concentration detector element. CONSTITUTION:A holder 5 is provided with a cup-shaped oxygen concentration detector element 2 that is closed at one end and open at the other end and a supply pipe 3. When the element 2 and a part of the holder 5 are submerged in the chemical plating liquid 1 that contains platinum, and the inside of the holder 5 is pressurized, the chemical plating liquid 1 goes down in the pipe 3 and passes through an annular route between the element 2 and the pipe 3 from the side of the closed end of the element 2 to be discharged through a communicating hole 4. Next, the pressure in the holder 5 is removed and the chemical plating liquid 1 is made to flow in through the communicating hole 4 and the plating liquid 1 is introduced into an element 2 to return to the state before the pressurizing. By repeating this process, the plating liquid recycles and an electrode of uniform thickness is formed. |
