Thick-film resistive temperature sensors

This paper discusses thick-film resistive temperature sensors investigated at the Technical University of Wroclaw. The technology and electrical properties of resistance temperature detectors, thermistors, low-temperature thermometers and heating elements are presented. The R(T) curve of chosen air-fireable NI-P based films agrees with Ni wire. The initially aged thermistors from the Mn1.6Co0.8Ni0.35Ru0.25O4/RuO2/glass system can operate in the range from roam temperature up to 673 K. The commercial thick-film resistors modified by the negative TCR drivers (e.g. TiO2 powder) are fully suitable for low-temperature measurements in the range from 20 to 100 K. The integrated gas sensors need heaters because temperature influences their sensitivity, selectivity and response time. The RuO2/Au thick-film compatible system based on commercially available resistive and conductive inks allows continuous long-term electrical heating of the sensor up to 673 K. The admissible operating temperature is much higher for the heaters made from conductive inks; for example fritless platinum heaters are satisfactory up to 1073 K.