Corrosion Performance of Advanced Alloys in Marine Environments

Abstract

Marine environments present highly aggressive conditions for engineering materials due to the combined effects of chloride-rich seawater, humidity, temperature variations, and biological activity, leading to accelerated corrosion and structural degradation. Conventional alloys often fail to provide long-term durability under such conditions, necessitating the development and evaluation of advanced corrosion-resistant alloys. This study investigates the corrosion performance of advanced alloys in marine environments with a focus on their electrochemical behavior, surface degradation mechanisms, and protective oxide layer formation. The methodology involves the preparation of alloy specimens such as stainless steels, aluminum-based alloys, titanium alloys, and nickel-based superalloys, followed by controlled exposure to simulated seawater conditions. Corrosion behavior is evaluated using electrochemical techniques including potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and open circuit potential (OCP) measurements. Surface morphology and compositional changes after exposure are analyzed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The results indicate that advanced alloys exhibit significantly improved corrosion resistance compared to conventional materials, primarily due to the formation of stable passive oxide layers that inhibit further electrochemical reactions. Titanium and nickel-based alloys demonstrate superior performance with lower corrosion rates and higher polarization resistance. Stainless steels show moderate resistance, which is further enhanced through alloying and surface treatment modifications. It is also observed that localized corrosion such as pitting is a major degradation mechanism in chloride-rich environments.