Assessing the Corrosion Resistance of Eco-friendly Steel Alloys in Marine Environments

Thesis Abstract

The increasing demand for sustainable construction materials in marine infrastructure has propelled the exploration of eco-friendly steel alloys with enhanced corrosion resistance, addressing environmental concerns associated with conventional steel production and degradation in marine environments. This study aims to evaluate the corrosion behavior of newly developed environmentally friendly steel alloys designed for marine applications, with specific objectives to compare their corrosion rates to conventional alloys, identify the microstructural characteristics influencing corrosion resistance, and assess the environmental impact of their deployment in marine settings. A mixed-methods approach was employed, integrating quantitative laboratory-based experiments with qualitative microstructural analyses. The research adopted a descriptive and experimental design. The population for the quantitative component consisted of three steel alloy formulations, including two eco-friendly compositions and a conventional control, with a total of 30 samples (10 per formulation) prepared using standardized casting procedures. For field validation, a sample size of 24 panels (8 per alloy type) was surface-treated and immersed in marine environments at three different coastal locations over a 12-month period. Laboratory corrosion testing involved electrochemical techniques such as Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS), complemented by surface characterization through Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analysis. Data were analyzed using Analysis of Variance (ANOVA) to compare corrosion rates and regression analysis to determine relationships between microstructural features and corrosion behavior. The qualitative microstructural data were analyzed via thematic analysis to interpret influence mechanisms. The study anticipates that eco-friendly steel alloys will demonstrate statistically significant improvements in corrosion resistance compared to conventional counterparts, attributed to refined microstructural features such as grain size and phase composition. It is expected that the new alloys will display lower corrosion current densities and higher impedance values, indicating better protective properties in marine conditions. Findings are projected to reveal that certain alloying elements, such as biogenic corrosion-inhibiting compounds, contribute positively to corrosion mitigation. This empirical evidence aims to fill gaps in current literature concerning sustainable steel formulations suitable for harsh marine environments. The study is expected to contribute to the theoretical framework of corrosion science by correlating microstructural attributes with corrosion performance, grounded in the principles of materials science and electrochemical theory. The primary contribution to knowledge lies in demonstrating the feasibility of sustainable steel alloys that outperform traditional materials in corrosive marine settings, thereby promoting environmentally responsible engineering practices. Main conclusions will emphasize the technical viability and environmental advantages of eco-friendly alloys, recommending their adoption in marine infrastructure projects. The study advocates for further long-term field assessments and exploration of environmental impacts through lifecycle analyses to validate scalability and sustainability. Overall, this research offers a significant advancement in the development of corrosion-resistant, eco-friendly steel alloys and provides practical guidelines for their implementation in marine environments, supporting global efforts toward sustainable engineering solutions and environmental conservation.