Identification of Corrosion Minerals Using Shortwave Infrared Hyperspectral Imaging

Area of Science:

• Materials Science
• Analytical Chemistry
• Corrosion Science

Background:

• Corrosion of carbon steel leads to significant material degradation.
• Accurate identification of corrosion products is crucial for understanding and mitigating steel deterioration.
• Traditional methods for analyzing corrosion products can be time-consuming and destructive.

Purpose of the Study:

• To develop and validate a novel method for identifying corrosion minerals in carbon steel.
• To utilize hyperspectral imaging (HSI) in the shortwave infrared (SWIR) range for mineralogical analysis.
• To assess the capability of HSI in detecting mineral composition changes over time.

Main Methods:

• Artificial corrosion of seven carbon steel samples using a neutral salt spray test.
• Acquisition of hyperspectral data in the 900-1700 nm range using a hyperspectral camera.
• Application of a normalized cross-correlation algorithm with reference spectra for mineral identification.
• Validation of HSI results using Fourier Transform Infrared (FTIR) spectroscopy on scraped corrosion powders.

Main Results:

• The hyperspectral imaging technique successfully identified four key corrosion minerals: goethite, magnetite, lepidocrocite, and hematite.
• HSI demonstrated high accuracy in detecting the dominant mineral present in the corroded samples.
• The study confirmed HSI's ability to predict temporal changes in the mineral composition of corrosion products.

Conclusions:

• Hyperspectral imaging in the SWIR range is a powerful, non-destructive tool for identifying corrosion minerals in carbon steel.
• HSI provides accurate insights into the mineralogical makeup and evolution of corrosion products.
• This method offers a significant advancement for corrosion monitoring and material assessment.