Abstract
Fine thermocouples of type-K were fabricated to weld a chromel wire and an alumel wire of 50μm by non-contact discharge welding method. The sizes of the hot junction can be controlled by the butt angle of two before the welding. Eight thermocouples, of which junctions were ranging from 43 to 126μm, were prepared. Their response rate and electromotive force (EMF) were measured, and composition of the junction was analysed by EDX. The response rate increases with a decrease in the size of the junction. EMF, i.e. indicated temperature, of the fine thermocouple was verified by heating from 200 to 350℃ with a commercial thermocouple of 0.65mm. The indicated temperature is 2-7degrees lower than that by the commercial thermocouple. However, EMF shows good linearity.
