Thermal spray metallic coatings are extensively used to safeguard steel substrates from corrosion in vital infrastructure such as bridges, storage tanks, and electrical structures, providing an effective physical barrier. However, the inherent porosity of these coatings can lead to the penetration of water, oxygen, and corrosive agents, resulting in localized corrosion, such as pitting, beneath the coating. To improve corrosion protection in harsh atmospheric conditions, selecting the right coatings and integrating real-time monitoring solutions is crucial. This study evaluates the corrosion protection capabilities of two Zn-Al thermal spray coatings, Zn-Al pseudo alloy and Zn-15Al alloy, applied to steel substrates. The corrosion resistance and propagation behavior of these coatings are assessed using distributed fiber optic sensors (DFOSs), which utilize optical frequency domain reflectometry (DFOR) to provide high spatial resolution, distributed sensing, and robust environmental durability. The results highlight the superior corrosion protection provided by Zn-Al coatings and demonstrate the effectiveness of DFOS for continuous, real-time monitoring and detailed evaluation of corrosion progress in steel substrates.
