Detection of different chemical binders in coatings
Organic coatings protect metallic structures of significant commercial value. Regular inspections of coatings are required to ensure their integrity and, therefore, to verify their stated performance.
However, for metallic structures located in harsh places, coating inspection can pose significant safety and logistical challenges. Near-infrared (NIR) spectroscopy is a rapid, nondestructive and relatively inexpensive analytical technique. It is currently employed to analyse different chemicals in fields like agriculture, food, and pharmaceuticals. Similarly, hyperspectral imaging (HSI) creates a spatial map of spectral information by measuring light reflected from a material.
Hyperspectral imaging
In a new work, hyperspectral imaging in the NIR portion of the electromagnetic spectrum (NIR-HSI) was used to accurately distinguish between the chemically different binders employed in commercial organic coatings. In addition, k-means clustering is explored as a tool to provide diagnostic information about the spatial inhomogeneities in the chemical structure of an applied coating, which, if undetected, can lead to coating defects during service life. The results of the work suggest that the NIR-HSI could be used for remote inspections of organic coatings.
The study has been published in Journal of Coatings Technology and Research, Volume 19, 2022.
