Abstract | Phenolic coatings, used to protect the steel of railcar tanks during the shipment of concentrated sulfuric acid, break down after repeated routine washings with water. To simulate this maintenance, coated metal specimens have been immersed in acid with periodic immersion in water for 1 h followed by drying and return to acid. Physical and chemical changes in the coating were determined by electrochemical impedance spectroscopy and diffuse reflectance Fourier transform infrared spectroscopy respectively while proton-induced X-ray emission served to determine the sulfur content. A model based on the dissolution of the filler and the pigment causing an increased porosity is proposed to explain the accelerated loss of protection from the coating. |
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