Preparation and Properties of Au/SnO2 Thermocouples for Material Testing Apparatus of Pressure Equipment

Thermocouples are the most common temperature measuring components in petrochemical, metallurgical, aerospace and other fields. However, due to the influence of working environment and its own structural characteristics, the thermocouple is highly susceptible to electromagnetic interference in the environment during its work, which seriously affects its temperature measurement accuracy. In this paper, three different shapes of Au/SnO2 thermocouples were prepared by screen printing technology, and their microstructure, thermoelectric properties and anti-electromagnetic interference were studied. The results show that the Au/SnO2 thermocouples with different shapes can crystallize well after sintering at 750 °C and above. When temperature difference is from 50 to 300 °C, thermocouples with different shapes can produce stable thermoelectric potential, and the shape has no effect on the output thermoelectric potential. The Au/SnO2 thermocouple after 850 °C sintering has the best thermoelectric performance. Au/SnO2 thermocouples can work normally in electromagnetic fields of 3 V/m or less, while standard PtRh10-Pt thermocouples can not work normally in electromagnetic field of 3 V/m. The Au/SnO2 thermocouple obtained in this study has the advantages of simple preparation method, small size, stable output thermoelectric potential and strong anti-electromagnetic interference ability.