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Photothermocapillary Method for the Nondestructive Testing of Solid Materials and Thin Coatings
Aleksandr Zykov1,2, Vladimir Vavilov3, Marina Kuimova3
1Research Laboratory of Photonics and Microfluidics, Tyumen State University, 625003 Tyumen, Russia.
Sensors (Basel, Switzerland)
|October 13, 2021
Summary
The photothermocapillary (PTC) effect uses laser-induced surface tension changes to detect material defects. This technique non-destructively measures coating thickness and identifies subsurface voids in solid materials.
Area of Science:
- Physics
- Materials Science
- Non-Destructive Testing
Background:
- The photothermocapillary (PTC) effect describes liquid surface deformation due to temperature-dependent surface tension.
- PTC techniques leverage sensitivity to thermal conductivity for non-destructive material analysis.
Purpose of the Study:
- To evaluate the PTC effect for non-destructive testing of solid materials.
- To monitor the thickness of varnish-and-paint coatings (VPC).
- To measure air-filled delaminations between coatings and metal substrates.
Main Methods:
- Excitation of the PTC effect using a Helium-Neon laser for monochromatic light.
- Analysis of optical interference patterns generated by laser reflection from the liquid surface.
- Quantification of the PTC response based on interference ring diameters.
Main Results:
- Demonstrated the PTC technique's sensitivity to thermal conductivity variations.
- Successfully monitored the thickness of VPCs on thermally conductive solids.
- Measured the thickness of air-filled delaminations between metal substrates and coatings.
Conclusions:
- The PTC technique is effective for non-destructive evaluation of material properties and defects.
- PTC offers a viable method for precise thickness measurements of coatings and delaminations.
