PLATINUM THERMOCOUPLE WIRE

摘要

The purpose of the present invention is to provide a platinum wire in which crystal growth is slowed to prevent damage resulting from creep without dispersing a metal oxide, and slip at crystal grain boundaries is slowed. A platinum thermocouple wire according to the present invention is used at the negative electrode of a platinum thermocouple and has a nitrogen mass concentration of 10 to 100 ppm. When the structure of the platinum thermocouple wire is observed in the longitudinal direction of the wire, a structure is observed in which there are a plurality of crystal grains in the wire thickness direction having an aspect ratio (major axis length/length of minor axis orthogonal to major axis) extending in the longitudinal direction of the wire of 5 or more.