Thermal characterization of vertical interface by scanning photothermal radiometry

Area of Science:

• Materials Science
• Non-destructive Testing
• Thermal Analysis

Background:

• Micro-cracks pose significant risks in structural integrity.
• Accurate characterization of submicron defects is crucial for material reliability.
• Non-destructive evaluation techniques are essential for assessing material health.

Purpose of the Study:

• To image and characterize a submicron crack using scanning photothermal radiometry.
• To map the spatial evolution of the crack with micrometer resolution.
• To estimate the thermal boundary resistance and average thickness of a micro-crack interface.

Main Methods:

• Utilized scanning photothermal radiometry for thermal imaging.
• Modeled heat transfer in a semi-infinite vertical crack using the thermal quadrupole approach.
• Employed phase mapping for quantitative analysis of the crack interface.

Main Results:

• Successfully mapped the spatial evolution of a submicron crack.
• Estimated the equivalent thermal boundary resistance of the steel-steel interface.
• Determined the average interface thickness of the micro-crack, found to be less than 0.5 μm.

Conclusions:

• Scanning photothermal radiometry is a viable technique for submicron crack characterization.
• The thermal quadrupole model accurately represents heat transfer across the crack interface.
• Quantitative thermal property estimation is achievable for micro-scale defects.