Design and evaluation of high-strength, corrosion-resistant aluminum alloy coatings

Thesis Abstract

The persistent demand for durable and lightweight materials in aerospace, automotive, and marine industries necessitates advancements in aluminum alloy coatings that combine high strength with exceptional corrosion resistance. Despite the widespread use of aluminum alloys owing to their favorable strength-to-weight ratio, inherent susceptibility to corrosion limits their application lifespan and economic viability, prompting the need for innovative coating solutions that enhance longevity without compromising mechanical performance. This study aims to design and evaluate novel aluminum alloy coatings that optimize strength and corrosion resistance through innovative materials engineering and surface modification techniques. The specific objectives include (1) synthesizing and applying a series of composite aluminum alloy coatings incorporating nano-scale corrosion inhibitors and reinforcement particles; (2) characterizing the mechanical properties and microstructural features of the developed coatings using scanning electron microscopy (SEM), X-ray diffraction (XRD), and microhardness testing; (3) assessing corrosion resistance through electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS); and (4) establishing the relationship between coating composition, microstructure, and corrosion behavior using regression analysis and analysis of variance (ANOVA). A mixed-methods research design was adopted, integrating experimental laboratory work with quantitative data analysis. The population comprised aluminum alloy substrates commonly employed in structural applications, with a sample size of 60 specimens divided equally among five coating formulations, including a control group with uncoated alloys. Coatings were applied via thermal spray techniques, with each batch subjected to standardized heat treatment procedures to ensure consistency. Data collection involved microscopic examination for microstructural analysis, mechanical testing for strength evaluation, and electrochemical testing for corrosion performance. Validity and reliability of experimental instruments were ensured through calibration, replication of tests, and statistical validation of results. Data analysis employed advanced analytical techniques, including regression modeling to identify correlations between coating composition and corrosion resistance, and ANOVA to evaluate the significance of observed differences across coating formulations. The study also utilized surface area analysis and phase quantification from XRD data to elucidate microstructural contributions to coating performance. It is anticipated that the results will demonstrate significant improvements in both mechanical strength and corrosion resistance for the optimized composite coatings relative to conventional aluminum alloys. Specifically, enhanced microhardness values exceeding 250 HV and corrosion current densities reduced by at least 60% are expected. These findings will elucidate the critical role of nano-reinforcements and corrosion inhibitors in developing multifunctional coatings suitable for aggressive environments. The research will contribute new insights into the microstructural mechanisms underpinning coating performance, offering a comprehensive framework for engineered surface enhancements in aluminum alloys. It will extend theoretical understanding by validating the applicability of surface passivation and nano-reinforcement theories within the context of advanced metallic coatings. The study's contribution to knowledge includes establishing a scientifically grounded, reproducible methodology for fabricating high-performance aluminum alloy coatings with tailored properties. It is expected that the results will inform industry best practices and guide further innovations in coating technologies, emphasizing scalability and environmental sustainability. In conclusion, the study recommends integrating the most effective coating formulations into industrial processes to extend the service life of aluminum-based components. Future research should explore long-term field testing under diverse environmental conditions, investigate the environmental impact of coating constituents, and optimize application techniques for large-scale implementation. This research aims to bridge current knowledge gaps and foster the development of durable, corrosion-resistant aluminum alloys that meet the rigorous demands of advanced structural applications, ultimately contributing to enhanced material performance, economic efficiency, and environmental sustainability.