All-Three-Dimensionally-Printed AgPd Thick-Film Strain Gauge with a Glass–Ceramic Protective Layer for High-Temperature Applications

Abstract

A high-temperature thin/thick-film strain gauge (TFSG) shows development prospects for in situ strain monitoring of hot-end components due to their small perturbations, no damage, and fast response. Direct ink writing (DIW) 3D printing is an emerging and facile approach for the rapid fabrication of TFSG. However, TFSGs prepared based on 3D printing with both high thermal stability and low temperature coefficient of resistance (TCR) over a wide temperature range remain a great challenge. Here, we report a AgPd TFSG with a glass–ceramic protective layer based on DIW. By encapsulating the AgPd sensitive layer and regulating the Pd content, the AgPd TFSG demonstrated a low TCR (191.6 ppm/°C) from 50 to 800 °C and ultrahigh stability (with a resistance drift rate of 0.14%/h at 800 °C). Meanwhile, the achieved specifications for strain detection included a strain sensing range of ±500 με, fast response time of 153 ms, gauge factor of 0.75 at 800 °C, and high durability of >8000 cyclic loading tests. The AgPd TFSG effectively monitors strain in superalloys and can be directly deposited onto cylindrical surfaces, demonstrating the scalability of the presented approach. This work provides a strategy to develop TFSGs for in situ sensing of complex curved surfaces in harsh environments.

Printed Thick Film Resistance Temperature Detector for Real-Time Tube Furnace Temperature Monitoring

“…During the material synthesis process, variations in prepared samples often occur due to differences in their locations. The AgPd alloy slurry, due to its advantages of low TCR and high-temperature resistance, has been extensively utilized as a sensitive material for strain sensors and solder joint materials [44,45]. To investigate the impact of the temperature field within the tube furnace on the sintering quality of alloys, AgPd alloys underwent sintering at distinct locations corresponding to the temperature-measuring ring array (Figure 7d).…”