[Means of manufacturing platinum microcathodes with a mirrored operating surface]

An arc-type discharge in a protective medium was used in manufacturing miniaturized cathodes with mirror working surface for memranous PO2 sesnsors. The obtaine thereby spherical fused end of the platinum wire has a diameter measuring from 35 to 120 micronm, being dependent both on the length of the wire and on the magnitude of the applied discharge voltage. Platinum should be fused into the glass capillary tube in the oxidizing zone of the flame.