| 摘要 |
PURPOSE:To obtain accurate measured value without the reduction in responding speed, by a method wherein a precious metal is deposited on the surface of a high-insulating glass rod by an ion spattering method or the like to form a toroidal cathode with a microarea. CONSTITUTION:After the surface of a high-insulating glass rod 9 is cleansed, it is attached to the inside of an ion spattering device, platinum spattering is effected in an atmosphere of argon gas with a pressure of 5 X 10<-2>mm.Hg as rotation is applied to the glass rod to form a toroidal platinum layer 10. The obtained glass rod 9 is sealed in a glass tube 11 with an outer diameter, being larger than that of the rod 9, with an epoxy series adhesive agent 12, and after the adhesion agent is cured, the work is cut to a given length to form a cathode for use with an oxygen partial pressure sensor. The use of said cathode enables to perform a reliable measurement without the reduction in responding speed and without exercising any influence even on a change in velocity of flow in the proximity of the sensor and on unevenness of gas transmissivity of an electrode film. |
