Silver–Platinum Thick-Film Strain Gauge With Low TCR and High Stability Based on Alloying Strategy

Enhancing the high-temperature stability of sensors for extreme environments while reducing manufacturing complexity and cost is crucial for sensor development. However, current thin-film strain gauges often struggle to achieve both low-temperature coefficient of resistance (TCR) and high thermal stability. This study developed a high-temperature thick-film strain gauge (TFSG) through Ag and Pt doping and used laser patterning to fabricate flexible masks, the sensitive layer was prepared by a blade-coating process, which offered the advantages of fast and efficient deposition. Furthermore, forming Ag/Pt alloys at high temperatures enhanced the material’s temperature resistance and stability. The TCR of Ag/Pt TFSG is only 191 ppm/°C, ten times lower than Ag TFSG’s. At room temperature, the gauge factor (GF) of strain-resistance is 1.25, the correlation coefficient is 0.983, and the response time under a 500- $\mu \varepsilon $ strain is 0.52 s. After 6 h at $800~^{\circ }$ C, the resistance drift rate (DR) is only 0.18%/h, and the strain GF of Ag/Pt TFSG at $800~^{\circ }$ C is 1.75. These results show that Ag/Pt TFSG based on alloy strategy optimization has a higher upper temperature limit and stronger anti-interference ability than Ag TFSG, and can be applied to strain signal measurement in extreme environments up to $800~^{\circ }$ C.