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Corrosion inhibition mechanism of a surfactant admixture on carbon steel alloy ASTM A36 [UNS K02600] coated with a high performance UV-cured coating

Rodriguez, Alvaro A.
http://orcid.org/0000-0002-3489-2954
http://rave.ohiolink.edu/etdc/view?acc_num=akron1460564870

Abstract Details

2016, Doctor of Philosophy, University of Akron, Chemical Engineering.
Several studies have been published describing the corrosion inhibition effectiveness of surfactant admixtures by measuring the ability of surfactant molecules to physically adsorb onto metal surfaces. However, the effects of these admixtures have not been previously studied on coated metal surfaces to determine their corrosion inhibition mechanism. While corrosion protective coatings isolate exposed metal surfaces by forming a barrier between a substrate and the electrolyte, their performance is highly dependent on their interaction with their immediate environment. During the winter season in Snowbelt areas where chloride roadway deicers are greatly employed, coated metal surfaces in vehicles are constantly exposed to harsh and changing environments making them susceptible to failure. In order to extend the service life of these exposed coated surfaces, additional treatment by surfactant admixtures is regarded as an effective corrosion prevention strategy. In this work, the corrosion mechanism of surfactant admixtures on coated metal panels is evaluated by understanding the interaction of the liquid-solid interface. Despite the numerous mechanisms of inhibition behavior, it is hypothesized in this study that the contributions from inhibition solution systems create a protective layer over substrates by the formation of multi layers from aggregation or adsorption of surfactants. Furthermore, this study will help understand the relationship of the surface of corrosion protective coatings and the interaction with its environment. Electrochemical impedance spectroscopy (EIS) is applied to evaluate the corrosion performance of a high performance, low VOC, two component polyurethane enamel and a high performance UV-cured coating system on carbon steel alloy A36 under immersion testing of sodium chloride solutions of surfactant admixtures. This electrochemical technique permits the evaluation of the properties of the coating system by monitoring its degradation with respect to time by following changes in the impedance spectra. Data were recorded at room temperature by measuring the water uptake into the coating in the presence and absence of surfactant in 0.6 M NaCl solutions. The surface of the coated metal sample was evaluated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) validating the formation of a barrier in the interface of the substrate and the coating system. Furthermore, the affinity of surfactant admixtures on the polyurethane enamel and the UV-cured coated metal surfaces can be quantified by measuring the wettability of the surface via contact angle measurements. Surface tension theory and dynamic fluid properties will illustrate the ability of surfactants to either form a layer or adsorb into the pores of the coating system. Changes in the dynamic contact angle of surfactant admixtures on coated surfaces with respect to time elucidate the effect of surface roughness, heterogeneity, capillary imbibition and swelling on these fluid systems. Inhibition efficiency results on bare metal surfaces from accelerated corrosion testing (ASTM B117) showed that salt neutralizer solutions are alloy specific and concentration dependent; while laboratory testing results demonstrated the effect of the properties of these solutions by correlating critical wash concentration, static contact angle, chemical structure, and effective adsorption with inhibition efficiency. Quantitative and qualitative information gathered in this study provide the means for understanding the role of the kinetics of surfactant admixtures adsorption on the corrosion protection resistance of a high performance polyurethane coating and a high performance UV-cured coating system. Moreover, it may further aid in the design of corrosion mitigation systems by determining what properties of surfactant admixtures and coatings provide the best corrosion protection.
Chelsea Monty, Dr. (Advisor)
Scott Lillard, Dr. (Committee Member)
Gang Cheng, Dr. (Committee Member)
Christopher Miller, Dr. (Committee Member)
John Senko, Dr. (Committee Member)
221 p.
Automotive Materials; Chemical Engineering; Engineering; Materials Science; Physical Chemistry
UV-cured coating systems; salt neutralizers; surfactants; corrosion inhibition; corrosion protective coatings; department of transportation; snow and ice control; electrochemical impedance spectroscopy; wetting kinetics; imbibition; spreading

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Citations

  • Rodriguez, A. A. (2016). Corrosion inhibition mechanism of a surfactant admixture on carbon steel alloy ASTM A36 [UNS K02600] coated with a high performance UV-cured coating [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460564870

    APA Style (7th edition)

  • Rodriguez, Alvaro. Corrosion inhibition mechanism of a surfactant admixture on carbon steel alloy ASTM A36 [UNS K02600] coated with a high performance UV-cured coating. 2016. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1460564870.

    MLA Style (8th edition)

  • Rodriguez, Alvaro. "Corrosion inhibition mechanism of a surfactant admixture on carbon steel alloy ASTM A36 [UNS K02600] coated with a high performance UV-cured coating." Doctoral dissertation, University of Akron, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460564870

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Akron and OhioLINK.
Release 3.2.12