All-Three-Dimensionally-Printed AgPd Thick-Film Strain Gauge with a Glass-Ceramic Protective Layer for...

Area of Science:

• Materials Science and Engineering
• Additive Manufacturing
• Sensor Technology

Background:

• High-temperature thin/thick-film strain gauges (TFSGs) are crucial for in situ strain monitoring of hot-end components.
• Direct ink writing (DIW) 3D printing offers a rapid fabrication method for TFSGs.
• Achieving high thermal stability and low temperature coefficient of resistance (TCR) in 3D-printed TFSGs remains a significant challenge.

Purpose of the Study:

• To develop a 3D-printed TFSG with high thermal stability and low TCR for operation up to 800 °C.
• To investigate the potential of silver-palladium (AgPd) alloys and DIW for fabricating advanced TFSGs.
• To demonstrate the effectiveness of the developed TFSG for in situ strain monitoring in harsh environments.

Main Methods:

• Fabrication of AgPd thin/thick-film strain gauges using Direct Ink Writing (DIW) 3D printing.
• Encapsulation of the AgPd sensitive layer with a glass-ceramic protective layer.
• Regulation of Palladium (Pd) content within the AgPd sensitive layer.

Main Results:

• The AgPd TFSG exhibited a low TCR of 191.6 ppm/°C across a wide temperature range (50–800 °C).
• Ultrahigh stability was achieved, with a resistance drift rate of only 0.14%/h at 800 °C.
• The strain gauge demonstrated a strain sensing range of ±500 με, a fast response time of 153 ms, a gauge factor of 0.75 at 800 °C, and high durability (>8000 cycles).

Conclusions:

• The DIW-fabricated AgPd TFSG with a glass-ceramic protective layer successfully addresses the challenge of high thermal stability and low TCR.
• The developed TFSG effectively monitors strain in superalloys and can be deposited on complex curved surfaces, showcasing scalability.
• This work presents a viable strategy for developing TFSGs for in situ sensing in demanding, high-temperature environments.