Temperature self-compensation thin film strain gauges based on nano-SiO2/AgNP composites

Thin film strain gauges (TFSGs) are crucial in the monitoring of industrial components. The industrial critical components usually operate in variable temperature environments and temperature disturbances can significantly affect the reliability of strain detection. To improve the accuracy of strain measurement in micro-strain, in situ prepared TFSGs with near-zero temperature coefficient of resistance (TCR) are expected to be fabricated. In this study, a functional ink consisting of AgNPs and nano-SiO2 particles was developed. Utilizing direct ink writing (DIW) technology, the nano-SiO2/AgNP TFSGs with a TCR of 30 ppm per degrees C were successfully fabricated. These conductive composites complement the positive temperature coefficient (PTC) of metallic transport with the negative temperature coefficient (NTC) of electron hopping transport, achieving the temperature self-compensation of the TFSGs. The nano-SiO2/AgNP TFSGs exhibited a high sensitivity, stability, durability and anti-interference toward temperature.