In‐Situ Atmospheric Corrosion Monitoring of Coated Aluminum Alloys Exposed in Tropical Monsoon Climate
Discuss this preprint
Start a discussion What are Sciety discussions?Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Organic coating is the most applied method for corrosion protection. However, they can degrade over time by the effect of UV, moisture, and corrosive media. In order to monitor the coating performance for proper maintenance planning, an electrochemical sensor was fabricated from aluminum alloy and coated with 4 coating systems: (1) epoxy primer, (2) epoxy primer/polyurethan topcoat, (3) epoxy primer/ polyurethan topcoat/ aluminum powder-containing polyester resin, and (4) epoxy primer/ polyurethan topcoat/ aluminum powder-containing polyester resin/ acrylic. The sensors were exposed together with corresponding coupon samples at Pathum Thani (PTI: suburban) and Chon Buri (CBI: mild marine) in Thailand for 2 years. Electrochemical impedance spectroscopy measurement (EIS) via the sensor recorded the impedance and capacitance of coatings with parallel meteorological monitoring. Impedance data were converted into a Coating Aging Index to evaluate degradation. Rapid coating deterioration occurred at PTI during wet seasons, while CBI showed negligible changes. Among the examined variables via machine learning model, exposure time most strongly influenced coating degradation. Single epoxy layer exhibited the lowest durability, whereas additional polyurethane, aluminum‑pigmented polyester, and acrylic coatings provided progressively superior protection.