Local temperature surface measurement with intrinsic thermocouple

Abstract

This paper reports on a technique based on the well-known Seebeck effect to measure local surface temperature. The aim of this work is to increase the spatial resolution of temperature measurement performed using thermocouples. The method relies on an intrinsic thermocouple consisting of a conducting tip put in contact with a conducting sample. The tip is made of nickel or constantan wires fabricated using an electrochemical etching process. This paper shows that the electric behavior of an intrinsic junction is similar to the one of a standard soldered thermocouple. The main difference between these two techniques is the localization of the measure. For a standard soldered thermocouple, the temperature value is the result of an average of the real temperature of the weld volume while for an intrinsic thermocouple the temperature information is localized in the contact area. The first experimental results actually confirm that a better spatial resolution can be obtained in the case of the intrinsic method, compared to a standard soldered thermocouple used in the same experimental conditions.