Enhancing Corrosion Resistance of Aluminum Alloys in Aerospace Industry Through Surface Treatments

Thesis Abstract

In the aerospace industry, aluminum alloys are extensively employed due to their high strength-to-weight ratio and durability; however, their susceptibility to corrosion significantly compromises structural integrity and safety, necessitating the development of effective surface treatment techniques to enhance corrosion resistance. This study aims to investigate and optimize surface treatment methods for improving the corrosion resistance of aluminum alloys used in aerospace applications. Specifically, the research seeks to evaluate the efficacy of various surface modification techniques—including anodization, chemical conversion coatings, and laser surface alloying—on aluminum 2024-T3 and 7075-T6 alloys, which are predominant in aerospace structures. The primary objectives are to quantify the corrosion resistance imparted by these treatments, analyze surface morphology and composition post-treatment, and identify the optimal treatment parameters for industrial application. The research adopts a mixed-methods approach, integrating quantitative laboratory testing with qualitative surface analysis. The experimental design involves a sample size of 150 aluminum alloy specimens, divided into five groups representing different surface treatment combinations, including a control group with no treatment. Data collection includes electrochemical impedance spectroscopy (EIS), potentiodynamic polarization tests, and salt spray chamber exposure to assess corrosion behavior, complemented by surface characterization techniques such as scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The validity and reliability of measurement instruments are ensured through calibration with certified standards and repeated trials, while data analysis employs statistical tools such as ANOVA to compare corrosion current densities and impedance values across treatment groups. Regression analysis models will be used to correlate surface roughness, coating thickness, and composition with corrosion performance, guided by the Theory of Surface Modification and Electrochemical Kinetics frameworks. Expected findings include statistically significant improvements in corrosion resistance—evidenced by higher impedance and lower corrosion current densities—in treated specimens compared to untreated controls. It is anticipated that anodization, particularly when combined with subsequent laser surface alloying, will demonstrate superior corrosion resistance owing to refined surface morphology and formation of protective oxide layers. The surface analyses are expected to reveal increased uniformity, thicker oxide coatings, and optimized surface energy profiles that contribute to corrosion mitigation. This research contributes to the existing body of knowledge by systematically comparing multiple surface treatment techniques within a unified experimental framework, filling gaps related to the combined effects of surface modification methods on aluminum alloys specifically tailored for aerospace use. It advances theoretical understanding by elucidating the mechanisms through which improved surface integrity enhances corrosion resistance. The study also offers practical insights into the industrial implementation of surface treatments, including optimal process parameters and material compatibility considerations. The main conclusion underscores the potential of integrated surface modification approaches, particularly anodization followed by laser alloying, to significantly extend the lifespan and safety of aluminum aerospace components by enhancing their corrosion resistance. Recommendations for industry include adopting these optimized treatment protocols, establishing quality control standards based on surface characterization metrics, and considering environmental and economic factors for large-scale application. The study further suggests avenues for future research, such as exploring nanostructured coatings and investigating long-term durability under operational aerospace conditions. Ultimately, this work aims to contribute to safer, more durable, and environmentally sustainable aerospace materials.