Study on Method for Measuring Coating Emissivity by Applying Active Irradiation Based on Infrared Thermal Imager

Area of Science:

• Materials Science
• Optical Engineering
• Thermal Engineering

Background:

• Accurate measurement of coating emissivity is crucial for various applications, including thermal management and remote sensing.
• Existing methods often face challenges with non-contact, room-temperature measurements, environmental interferences, and speed.
• Developing a rapid and precise non-contact method for emissivity measurement is highly desirable.

Purpose of the Study:

• To propose and validate a new measurement method for rapid and precise non-contact determination of coating emissivity at room temperature.
• To eliminate the influence of atmospheric transmittance, target radiation, environmental radiation, and atmospheric path radiation.
• To compare the proposed method's performance against existing techniques in terms of accuracy and speed.

Main Methods:

• Utilized an infrared thermal imager and a surface blackbody radiation source.
• Applied two distinct energy irradiations to target and reference surfaces to cancel out interfering radiation sources.
• Investigated the impact of irradiation energy levels and differences on measurement outcomes.
• Generated a coating surface emissivity image in the mid-wave infrared band.

Main Results:

• The proposed method successfully eliminated interfering radiation factors, enabling accurate emissivity measurements.
• Experimental validation confirmed the method's effectiveness in measuring normal emissivity of coated sample plates.
• Comparison with energy method and point emissivity instruments showed superior performance of the proposed technique.
• Analysis identified key factors contributing to potential measurement errors.

Conclusions:

• The developed infrared thermal imager-based method provides a rapid, precise, and non-contact solution for coating emissivity measurement at room temperature.
• The technique effectively overcomes limitations of previous methods by mitigating environmental and atmospheric influences.
• This advancement offers significant potential for applications requiring accurate surface property characterization.