| 摘要 |
PROBLEM TO BE SOLVED: To provide a formation method, for an electrode for a senior element, in which the sensor element provided with the electrode of stable quality can be mass-produced. SOLUTION: When a platinum electrode for a sensor element is formed by an electroless plating operation on a solid electrolyte which is formed to be a prescribed shape, a tetraammineplatinum (II) complex solution is used as a plating liquid, and hydrazine which reduces a platinum (II) complex is made to act as a reducing agent. Since the platinum (II) complex has a four- coordinate planar structure, a high-purity product is easy to obtain as compared with a platinum (IV) complex as a six-coordinate octahedral structure. As a result, a plating precipitation speed due to the influence of impurities is not changed, and the film thickness of a platinum thin film is made nearly uniform. In addition, since the reducing process of divalent platinum is simple as compared with that of tetravalent platinum, impurities are not generated as a by- product in a reducing reaction. |
