Highly oriented platinum/iridium thin films for high-temperature thermocouples with superior precision

Area of Science:

• Materials Science
• Nanotechnology
• Thermometry

Background:

• Precise high-temperature measurement is crucial for various industrial applications.
• Thin-film thermocouples (TFTCs) offer rapid temperature detection but face challenges in development and standardization.
• Existing TFTC technologies exhibit limitations in long-term stability and accuracy at elevated temperatures.

Purpose of the Study:

• To develop an enhanced thin-film thermocouple (TFTC) with improved performance and stability.
• To investigate the impact of nanostructure and interface design on TFTC properties.
• To establish a new standard for high-temperature measurement using pure-element TFTCs.

Main Methods:

• Fabrication of a platinum/iridium (Pt/Ir) pure-element TFTC.
• Optimization of interface matching and defect reduction through nanostructure design.
• High-temperature calibration and stability testing over a range of 300 °C to 1000 °C.
• Analysis of film microstructure and crystallographic orientation.

Main Results:

• The fabricated Pt/Ir TFTC demonstrated excellent long-term service stability at high temperatures.
• Polynomial fitting coefficients consistently exceeded 0.99999, confirming accurate temperature data acquisition.
• Achieved a deviation of less than 0.21% across three calibration cycles, surpassing standard wire thermocouple precision.
• Superior properties were attributed to reduced defects and highly preferential (111) plane orientation in Pt and Ir thin films.

Conclusions:

• The developed Pt/Ir TFTC offers a significant advancement in high-temperature measurement technology.
• The nanostructure and interface engineering strategy effectively enhances TFTC performance and stability.
• Pt/Ir TFTCs show strong potential for applications in thermal detection, microelectronics, and aero-engines.