A fast and versatile method for spectral emissivity measurement at high temperatures

Area of Science:

• Materials Science
• Thermodynamics
• Optical Engineering

Background:

• Accurate measurement of material emissivity at high temperatures is crucial for thermal management and process control.
• Existing methods often lack versatility or simplicity, hindering broad application.

Purpose of the Study:

• To develop a novel device for measuring both spectral and total emissivity across a temperature range of 600-1000 °C.
• To prioritize device versatility and simplicity in its design and component selection.

Main Methods:

• Rigorous selection and optimization of heating systems, heat sources, sample holders (using ray tracing), and sensors.
• Utilized a near-infrared (NIR) spectrometer and mid-infrared (MIR) cameras with specific optical filters (3-5 μm and 7.5-13 μm).
• Developed specific measurement methodologies for each bandwidth to isolate sample signals from environmental interference.

Main Results:

• The device demonstrated good agreement for spectral emissivity measurements in NIR and MIR band I compared to a commercial spectrometer.
• MIR band II measurements showed a higher error rate due to a less favorable signal-to-noise ratio.
• Calculated integrated emissivity values showed good agreement with literature data, exhibiting similar temperature trends.

Conclusions:

• The developed device is validated for accurate spectral and total emissivity measurements at high temperatures.
• Its versatility and simplicity allow for adaptation to a wide range of applications.
• The study highlights the importance of careful component selection and tailored measurement strategies for high-temperature optical property characterization.