Recent Advances in Corrosion Protection of Marine Aluminum Alloys: A Review

Recent Advances in Corrosion Protection of Marine Aluminum Alloys: A Review

Alaa Shaker Obaida, Zahraa Kadhum Rodhan, Israa Adnan Najem

Department of Mechanical Techniques, Babylon Technical Institute, Al-Furat Al-Awsat Technical University, Hillah, Iraq

Abstract – The alloys created for marine applications are key to the maritime transport, shipping and offshore facilities industry, due to the strength, weldability and naturally corrosive resistance when in contact with seawater. The chloride ions are especially damaging to the 5xxx and 6xxx alloy series, which are primarily used in marine applications. But, over extended periods of time, severe chloride sea water exposure will inevitably result in various localized and electrochemical degradation processes, most notably pitting, galvanic interactions, intergranular attack, stress corrosion cracking (SCC) and erosion-corrosion. The effects of these phenomena are at the core of structural reliability and operational life. The present review critically analyzes the corrosion behavior of marine grade aluminum alloys, highlighting important fundamental corrosion mechanisms, environmental effects and electrochemical signatures. Systematic, methodological analysis of corrosion assessment methods, including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and standard accelerated testing, is undertaken. In addition, the paper presents the current developments in the protection paradigms such as advanced anodization, self-healing smart materials, graphene reinforced nanocoatings and eco friendly inhibitors. This review highlights potential future directions for using AI and nanotechnology to create very durable marine aluminum, identifying gaps in the current research in regards to long-term exposure durability and synergistic degradation factors.

Keywords

• Marine aluminum alloys

• Corrosion behavior

• Seawater corrosion

• Pitting corrosion

• Electrochemical impedance spectroscopy

• Smart coatings

• Graphene nanocoatings

1 .INTRODUCTION

As one of the most important advanced materials used today in the modern maritime industry, aluminum alloys are used to satisfy the demanding operational requirements. Some of the remarkable properties of these alloys include a very low density, a high specific yield strength and strong inherent corrosion resistance to seawater, which can have transformative effects compared to more conventional ferrous alloys [1]. Thus, marine grade aluminum finds wide applications in naval architecture, high speed marine craft,

complex offshore structures and optimisation of fuel efficiency with maximisation of payload capacity whilst maintaining structural integrity, primarily. [2][3]

Out of all the alloys that are commercially available, 5xxx alloys and 6xxx alloys are considered as the best operational synergy alloys for marine applications [4]. The 5xxx series (e.g., AA5083 and AA5086) contain magnesium, which strengthens the passive oxide film; the type of series gives very good resistance to chloride containing environments [5]. The 6 family of alloys represented by 6063 and AA6061, on the other hand, is intended for use in marine structural parts, where high formability and close tolerances are key features, and where machinability is also high.

Aluminum forms a passive film of oxide which protects it, but continuous exposure to a dynamic marine environment often times weakens the protection layer. This breakdown results in a progression of electrochemical failures at the local level including pitting, crevice attack and stress corrosion cracking [7]. The major cause of this passive film destabilisation is due to the high chloride ion concentration of the ocean water, particularly in stagnant waters or high chloride ion concentration [8]. The degradation not only affects the mechanical integrity of the components, but also it has a considerable influence on the general reliability of maritime systems.

The environment will involve temperature, pH, dissolved oxygen, microorganisms, and other factors, which will affect the nature of marine corrosion [9]. Apart from this, changes in the material structure that may happen during the manufacturing process, particularly the thermal stresses that can be generated in the HAZs during the welding process, further complicate the electrochemical stability of the material [10]. The behaviors are studied by a large number of state-of-the-art analytical methods such as electrochemical impedance spectroscopy (EIS), potentiodynamic mapping and high resolution (µ) surface microscopy images [11].. There is an urgent and growing need for improved durability which has driven cutting-edge research into novel protection modalities. Enhancing material preservation by integrating smart coating self-healing mechanisms, strong physical barriers made of graphene, and plasma electrolytic oxidation represents the next step in the field [12][15]. Hence, the aim of this review is to critically sketch the present scenario of marine corrosion of aluminum, examine the latest protective

measures against corroded aluminum and shed light on the key areas of sustainable future maritime engineering.

1. MARINE-GRADE ALUMINUM ALLOYS

   It is undeniable that aluminum alloys are essential in modern marine engineering, especially because of their intrinsic resistance to environmental damage, excellent weight to strength ratio and high tensile strength [1] [14] [41]. The use of traditional steel/aluminium alloy substitution allows significant savings in total weight of the structure, which optimizes fuel consumption, increases load carrying capacity and reduces operating costs [3] [42]. Offshore platforms, high-speed marine transportation and naval architecture are therefore heavily involved with these materials. These alloys can be divided and classified into different groups according to their main alloying elements and strengthening mechanisms. Of this metallurgical range, the 5xxx and 6xxx series wrought alloys are clearly the most popular choices over cast alternatives because of their excellent weldability, formability and continuous seawater exposure dynamic mechanical characteristics [43] and.]13[

   1. The 5xxx Series (Al-Mg Alloys)

      The 5xxx series is a non-heat treatable alloy group with magnesium as the main alloying element, which is used to obtain desired mechanical properties by strain-hardening processes [14]. The AA5083, AA5086 and AA5456 alloys are representative of the alloy group used in shipbuilding. Of particular interest is the combination of fracture toughness, weldability and resistance to chloride induced localized attack of AA5083 [15, 19]. Dissolution of magnesium in the aluminium matrix improves the protection surface oxide stability. These microstructures are susceptible to sensitization though, however, and can result in the continuous precipitation of the anodic -phase (AlMg) at grain boundaries due to prolonged thermal exposure or sub-optimal welding parameters, which can escalate the risk of intergranular corrosion and stress corrosion cracking [44 ] [20].

   2. The 6xxx Series (Al-Mg-Si Alloys)

      Alloys containing both magnesium and silicon, 6xxx series, are heat treatable alloys with moderate to high strength properties, and have good extrudability [14, 24]. Marine appliations often require AA6061 and AA6082 for structural framing, piping systems and support assemblies. They have excellent fabrication versatility, but are slightly less corrosion resistant than the 5xxx series. This is due to microstructural heterogeneities, that is the formation of strengthening phases during thermal treatments, which create local micro-galvanic cells around the precipitation areas with the surrounding aluminum matrix and therefore affect the local dissolution in aggressive chloride environments [7, 21]. The summary of metallurgical and operational properties of 5xxx and 6xxx series is given in Table 1

      .Table 1: Comparison of Wrought Marine-Grade Aluminum Alloys

      Feature / Characteristic	5xxx Series (Al-Mg)	6xxx Series (Al-Mg-Si)
      Primary Alloying Elements	Magnesium (Mg)	Magnesium (Mg) and Silicon (Si)
      Strengthening Mechanism	Non-heat-treatable (Strain hardened)	Heat-treatable (Precipitation hardened)
      General Marine Corrosion Resistance	Excellent (Highly stable oxide layer)	Good (Slightly inferior to 5xxx series)
      Weldability & Formability	Exceptional weldability	Excellent extrudability and machinability
      Primary Vulnerability	Sensitization (Intergranular attack & SCC)	Micro-galvanic cells at precipitate zones
      Common Marine Applications	Ship hulls, bulkheads, offshore structures	Piping, structural framing, support assembles

2. FUNDAMENTAL CORROSION MECHANISMS

   Although a passive amorphous oxide layer forms spontaneously, the harsh marine environment consisting of high concentrations of halides, dissolved oxygen and cyclic hydrodynamic forces often disrupts this passive layer [3, 45].

   1. Pitting Corrosion

      It is believed that pitting is the worst and common mode of degradation that is seen in aluminum structures in saline atmosphere [4]. It starts exactly at defects in the surface at which aggressive chloride ions are able to penetrate the passive film [8]. This rupture creates microscopic anodic sites, from which rapid, autocatalytic dissolution of the metal proceeds in the occluded pit cavity. The cathodic reduction reaction of dissolved oxygen (O + 2HO + 4e 4OH) occurs on adjacent protected surfaces with the anodic dissolution reaction of aluminum (Al Al³ + 3e), as shown in a schematic in Figure 1. In addition, the subsequent hydrolysis of aluminium ions in the pit cavity (Al³ + 3HO

      Al(OH) + 3H) creates a very localised acid micro-environment, which actively prevents repassivation and promotes the propagation of the cracks [46]. Pits are a major stress concentrator and can cause catastrophic structural fatigue 1, especially because they can grow deep into the substrate, with little apparent damage.

      Figure 1: Schematic illustration of the pitting corrosion mechanism in aluminum alloys.

   2. Galvanic and Crevice Corrosion

      Galvanic corrosion is the corrosion that occurs under the following circumstances: marine aluminum structure is electrically connected with a nobler alloy, such as a stainless steel fastener, a bronze marine propeller, and the conductive electrolyte is seawater [47]. Aluminum always serves as the sacrificial anode and is dissolved at an accelerated rate, which is directly proportional to the ratio of the area of the cathode to that of the anode [5], [33]. At the same time, crevice corrosion can be a very aggressive corrosion in confined geometrical spaces where stagnant electrolyte accumulates [13]. The differential aeration cell that follows causes the micro-environmental pH to decrease, which can greatly destabilize the passive film [5].

   3. Intergranular and Stress Corrosion Cracking (SCC)

      The intergranular degradation occurs along the grain boundaries of the microstructure, and is mainly coupled with the dissimilar metals of the precipitate-free zones and localized secondary phase [19]. This metallurgical susceptibility, upon sustained or residual tensile stresses, becomes what is known as Stress Corrosion Cracking (SCC) [48]. SCC is a synergistic mechanical-electrochemical failure mode in which micro-cracks grow quickly from the sensitized grain boundary network, and typically do not show up visually until at the point of imminent failure [6].

   4. Cavitation and Erosion-Corrosion

      Cavitation and erosion-corrosion are a serious problem in high-velocity systems where the fluid velocity is high, such as in marine applications [36]. Cavitation happens because the hydrodynamic collapse of the vapor bubbles creates a very strong localized shock wave that mechanically breaks up the passive oxide film. A key aspect of this degradation is evaluated through the tribological wear characteristics of this degradation; this is often modeled using a highly demanding laboratory setup like pin-on-disk configuration (see Figure 2

      for a typical setup) that provide insights into the mechanical removal of the surface layers [27]. The synergistic mechanical removal of film and its electrochemical repassivation is a continuing process that drastically shortens the operational life of the component [49, 36]. In Figure 3, all the different types of marine corrosion that affect aluminum alloys are summarized in a schematic.

      Figure 2: Tribocorrosion and erosion-corrosion evaluation utilizing a Pin-on-Disk setup in a simulated seawater environment.

      Figure 3. Schematic overview of the major corrosion forms affecting marine aluminum alloys, including pitting corrosion, crevice corrosion, stress corrosion cracking (SCC), galvanic corrosion, and erosion-

      corrosion.

3. METHODOLOGIES FOR CORROSION ASSESSMENT

   To accurately evaluate degradation kinetics of marine-grade aluminum requires the use of a strong analytical structure that is capable of simulating what actually happens when the

   material is placed in seawater. In most cases, a multimodal approach, combining accelerated environmental testing, dynamic electrochemical profiling and high-resolution surface metrology, is used when benchmarking the performance of a material [8, 26].

   1. Accelerated Environmental Exposure (Salt Spray Testing)

      The standardised ASTM B117 [11] continuous salt fog test continues to be a benchmark with which to evaluate the resistance of coating to chloride degradation and susceptibility of the substrate to the damage. Under the controlled thermodynamic conditions of the exposure to a constant atomized sodium chloride mist, a qualitative analysis of pit nucleation and coating delamination can be rapidly extrapolated from the specimens [11] [50].

   2. Potentiodynamic Polarization

      Potentiodynamic polarization is widely employed to investigate the fundamental mechanisms of corrosion initiation and repassivation in aluminum alloys [51], [52]. In this technique, a controlled potential sweep is applied to the working electrode to evaluate key electrochemical parameters, including the corrosion potential (Ecorr), corrosion current density (Icorr), and critical pitting potential (Epit).]53[

      The anodic dissolution of aluminum during polarization can be represented by:

      Al Al^3+ + 3e-^

      while the corresponding cathodic oxygen reduction reaction in aerated seawater is expressed as:

      O2 + 2H2O + 4e^- 4OH-^

      Based on Faradays law, the measured current response enables accurate estimation of corrosion kinetics and material degradation rates according to:

      CR = (K × Icorr × EW) /

      where CR is the corrosion rate, K is a constant, Icorr is the corrosion current density, EW is the equivalent weight, and is the material density. Consequently, potentiodynamic polarization remains highly effective for assessing the stability and durability of passive oxide films in aggressive marine environments [26]

      .4.3. Electrochemical Impedance Spectroscopy (EIS)

      Electrochemical Impedance Spectroscopy (EIS) is a very sensitive, non-destructive diagnostic technique that is well suited for decomposing complex interfacial charge transfer

      processes [54] and [17]. The passive layer capacitance, pore resistance and integrity of the coating can be valuable information from a minute AC perturbation over a wide frequency range [17]. Data synthesis with Nyquist and Bode formalisms can be used to quantify electrochemical resilience as these formalisms are often depicted as equivalent electrical circuits [8, 40]. The typical electrochemical impedance response for Marine aluminium alloys is given in Figure 4.

      Figure 4. Representative Nyquist plots obtained from electrochemical impedance spectroscopy (EIS)

      measurements of aluminum alloys exposed to 3.5 wt.% NaCl solution.

      4.4. Immersion Testing and Advanced Surface Characterization

      The results of the accelerated laboratory test can be validated against actual environmental parameters by performing an immersion long-term protocol using either synthetic seawater or natural seawater [55]. The traditional gravimetric analysis is made after the exposure and it is used to obtain average macroscopic corrosion rates. The majority of post-exposure microstructural auditing is carried out using mainly Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) [2,34]. This synergy enables high magnification topographical imaging of the propagation network of cracks and chemical mapping of corrosion products in localized areas and the crystallographic phases of the corrosion products are detected as oxides, using X-ray Diffraction (XRD).

4. ADVANCED PROTECTION STRATEGIES

   A hierarchy of barrier protection and electrochemical modification is required to protect marine aluminum infrastructure from constant marine attack by halides. For modern interventions, from simple barrier coating to complex nanoscale structures, that can effectively neutralize attacks at specific locations, see [15, 39]. We briefly summarize these higher-level protection strategies in Table 2 and describe them and their benefits below.

   1. Polymeric Barriers and Anodization

      For a long time, we’ve protected things with coatings of epoxy and polyurethane, that are all tangled together (cross-linked), and these create a very dense plastic layer. This layer stops water containing dissolved substances from getting at the metal underneath. Coating is very often done after anodizing, a process of controlled electrochemistry, to make the coating stick. Anodizing builds up the naturally forming aluminum oxide, making it thicker, much harder, more resistant to being worn away, and improving how well it protects against corrosion.

   2. Cathodic Protection Systems

      By making the structure more cathodic (pushing its electrical potential downwards) you can get it into a safe, or protected, range and so lessen how much metal dissolves from it. You can achieve this with a metal that will give up its own electrons to protect the structure, like zinc, or with a system of Impressed Current Cathodic Protection which is a network that actively forces current onto the metal. Its really important to get the protection level right. Too much polarization creates a strongly alkaline area, and then aluminum can suffer hydrogen embrittlement.

   3. Nanostructured and Graphene-Reinforced Coatings

      The use of nanotechnology has transformed marine barrier films. The introduction of nanoparticles like silicon dioxide, titanium dioxide, and carbonaceous derivatives into polymeric matrices can significantly decrease the porosity and constrain the tortuosity for ion transport [39]. More specifically, graphene nanosheets offer outstanding barrier properties, which effectively block the passage of chloride ions and, at the same time, increase the mechanical resistance of the composite [9]. Additionally, a new type of surface modification technique, namely Plasma Electrolytic Oxidation (PEO), has become a game-changing one; PEO creates very thick ceramic coating that is well attached to the surface and can withstand very harsh tribocorrosive environment [24].

   4. Eco-Friendly Inhibitors and Smart Hybrid Systems

      The move towards the use of biodegradable, green and environmental friendly corrosion inhibitors is increasing in pace, thanks to the high demands for the environment [23, 25]. These compounds react by adsorbing on the active metallic interfaces and slowing charge transfer kinetics without the need for toxic heavy metal precursor [25]. The use of hybridized systems (combining surface treatments with smart or self-healing polymer topcoats [10, 18]) is increasingly being adopted in the field of next generation marine defense systems. The self-repairing process frequently employs microencapsulated healing agents that spontaneously seal micro-fissures when they are broken or damaged, thus significantly prolonging maintenance-free life cycle of maritime structures [10]. A comparison of the

      significant corrosion protection methods for marine aluminum alloys is given in Figure 5.

      Figure 5. Comparative evaluation of advanced corrosion protection strategies for marine aluminum alloys based on corrosion resistance, durability, environmental

      friendliness, cost effectiveness, and overall performance.

      Table 2: Overview of Advanced Protection Strategies for Marine Aluminum

      Protection Strategy	Mechanism of Action	Key Advantages	Current Limitations
      Polymeric Barriers & Anodizing	Physical isolation from electrolyte; artificial oxide thickening.	Cost-effective, established technology, high wear resistance.	Susceptible to mechanical scratching and subsequent localized pitting.
      Cathodic Protection (ICCP/Sacrifici al)	Shifts electrochemi cal potential to the immune domain.	Continuous active protection against anodic dissolution.	Risk of over-polarization leading to alkaline attack and hydrogen embrittleme nt.
      Graphene-Reinforced Nanocoatings	Extends ion transport path (tortuosity) via 2D nanosheets.	Exceptional impermeabil ity to $Cl^-$ ions, enhanced mechanical strength.	Challenges in uniform dispersion within the polymer matrix; high fabrication cost.

      Protection Strategy	Mechanism of Action	Key Advantages	Current Limitations
      Self-Healing Smart Systems	Autonomous release of healing agents upon mechanical rupture.	Drastically extends maintenance -free lifecycle, neutralizes micro- cracks.	Long-term stability of microcapsul es in harsh environmen ts requires optimizatio n.

5. RECENT TECHNOLOGICAL BREAKTHROUGHS

   How we keep the bottoms of ships from rusting is getting an update. Instead of just putting up a sort of a wall against corrosion, were now being much more forward-looking with how we design the surface. This improvement is thanks to new developments in materials, incredibly small technology (nanotechnology) and being able to forecast what will happen, and all f this makes aluminum parts of ships last much longer in the difficult conditions of the sea.

   1. Smart and Self-Healing Coatings

      Self-healing coatings are an emerging area for marine maintenance mitigation. The smart composites differ from static barriers in the construction of stimulus-responsive microcapsules containing corrosion inhibitors and polymerizing agents [10], [18]. These capsules rupture, releasing active agents that seal and repassivate the surface of the aluminum substrate themselves upon mechanical rupture or with the onset of pitting due to local pH changes (Figure 6 shows the working mechanism of these microcapsules before and after damage).

      Figure 6: Working mechanism of microcapsule-based self-healing coatings.

      6.2 Graphene-Reinforced Nanocomposites

      The combination of 2D nanomaterials (graphene or graphene derivatives) has raised the performance of marine coatings [9]. This aspect ratio and the impermeability of graphene to gas and ion diffusion produces a very tortuous path for the chloride ions. As a result, graphene-epoxy and graphene-polymeric (epoxy and polyurethane) composites have very low porosity, good interfacial adhesion and high mechanical durability against erosion-corrosion [9] and [40].

      1. Advanced Surface Engineering

         The surface modification protocols have also been evolving with the advent of nanotechnology. The surface layer formed after plasma electrolytic oxidation (PEO) has proven to be very effective for the conversion of the native amorphous oxide layer of aluminum into a thick, crystalline layer of a ceramic-like material [24]. These surfaces would further exhibit high resistance to electrochemical dissolution and tribological wear when coated with nanoparticles (TiO, SiO, etc.) [55, 38].

      2. Artificial Intelligence and Predictive Modeling

      The extensive use of big data and machine learning in materials science has led to unparalleled predictive power of the degradation of structures [28], [35]. Using historical immersion data, real-time electrochemical monitoring and environmental data as inputs into Artificial Neural Networks (ANNs), researchers can accurately predict the likelihood of pitting, schedule maintenance more efficiently and rapidly discover new compositions of corrosion-resistant alloys [58, 40,56].

6. CURRENT RESEARCH GAPS AND FUTURE TRAJECTORIES

   Although significant advances have been made in strengthening marine aluminum alloys, there are still some important areas that require specific research in the future for the long-term durability of these alloys.

   1. Paucity of Long-Term In-Situ Data

      Most available literature on corrosion only uses accelerated laboratory experiments, such as salt spray tests [58]. The lack of long-term field exposure studies with comprehensive coverage, including the highly variable factors of natural sea water, e.g., biofouling, cyclic wetting and drying, and complex interactions among microorganisms [59,37] remains a significant gap.

   2. Synergistic Degradation Mechanisms

      Typically the research focuses on single failure modes, such as electrochemical pitting. In the marine environment, however, structures are subjected to additional stresses. The complex interaction between mechanical fatigue, hydrodynamic cavitation and electrochemical dissolution

      (tribocorrosion) are not well quantified especially for high strength 6xxx series alloys [57], [41].

   3. Microstructural Vulnerabilities in Welds

      Although manufacturing improvements have been made, welded marine aluminum is still very susceptible to galvanic and intergranular attacks, caused by local precipitation in HAZ and residual thermal stresses. The parameters and post-weld heat treatment of friction stir welding needs further optimization to enhance the material properties [42][59].

   4. Sustainability and Environmental Compliance

      Toxic heavy metal inhibitors and Volatile Organic Compounds (VOCs) in coatings will have to be removed from use as new regulations in the global maritime industry become stricter. The development of fully biodegradable, plant derived inhibitors and water-borne smart coatings is a huge challenge when trying to retain efficacy while maintaining environmental integrity [23, 60].

7. CONCLUSIONS

Although plastics are also employed in the marine industry for their low weight, they are not as strong as the aluminium alloys, which are especially useful in the 5xxx and 6xxx series with their perfect combination of low density and high structural strength . However, there are a number of modes of failure that are inherent to their use in chloride containing, highly corrosive, sea water, notably pitting, galvanic coupling and stress corrosion cracking . Given the constant degradation of the native passive film, rigorous electrochemical assessment methodologies are needed to truly decipher the degradation kinetics, such as EIS and potentiodynamic polarization . Although traditional anodization and polymeric barrier technologies are used for basic protection, the future of marine infrastructure will depend on the use of advanced multifunctional technologies. The use of graphene-based nanocoatings, self-healing smart polymers and eco-friendly inhibitors shows tremendous promise to lengthen maintenance periods . In conclusion, long-term in-situ testing and the addition of artificial intelligence to the current research gaps are going to be a key element in the development of the next generation of highly resilient and sustainable maritime aluminum systems .

REFERENCE

1. Davis JR. Corrosion of Aluminum and Aluminum Alloys. Materials Park, OH: ASM International; 1999.

2. Zhang XG. Corrosion and Electrochemistry of Zinc and Aluminum Alloys. Elsevier; 2019.

3. Song GL. Corrosion of aluminum alloys in seawater. Corrosion Science. 2012;54:110.

4. Frankel GS. Pitting corrosion of aluminum alloys: A review. Journal of The Electrochemical Society. 1998;145(6):21862198.

5. Revie RW, Uhlig HH. Corrosion and Corrosion Control: An Introduction to Corrosion Science and Engineering. 4th ed. Wiley; 2008.

6. Atrens A, Song GL. Understanding corrosion mechanisms in magnesium and aluminum alloys. Materials Science Forum. 2013;765:1218.

7. Birbilis N, Buchheit RG. Electrochemical characteristics of intermetallic phases in aluminum alloys. Journal of The Electrochemical Society. 2005;152(4):B140B151.

8. Xia L, et al. Electrochemical impedance spectroscopy study of 5xxx aluminum alloys in NaCl solutions. Electrochimica Acta. 2018;280:112120.

9. Zhang J, Wang H, Liu C. Graphene-based nanocomposite coatings for advanced marine corrosion protection. Progress in Materials Science. 2020;112:100662.

10. Liu Y, Li M, Chen J. Self-healing smart coatings for corrosion protection: A comprehensive review. Materials Today. 2021;45:88105.

11. ASTM International. Standard Practice for Operating Salt Spray (Fog) Apparatus. ASTM B117-19; 2019.

12. ASTM International. Standard Test Method for Conducting Potentiodynamic Polarization Resistance Measurements. ASTM G59-97; 2020.

13. Revie RW. Uhligs Corrosion Handbook. 3rd ed. Wiley; 2011.

14. Totten GE, MacKenzie DS. Handbook of Aluminum: Physical Metallurgy and Processes. Marcel Dekker; 2003.

15. Zhang X, Zhao T,Wang W. Marine corrosion of high-strength aluminum alloys: Mechanisms and advanced protection. Ocean Engineering. 2022;248:110825.

16. Isaacs HS, Ishikawa Y. Localized corrosion of aluminum in seawater environments. Journal of Marine Science and Technology. 2017;14:5563.

17. Mansfeld F. Use of electrochemical impedance spectroscopy for the study of marine corrosion systems. Corrosion. 1988;44(12):856868.

18. Zheludkevich ML, et al. Smart healing coatings for protection of marine aluminum structures. Surface and Coatings Technology. 2007;201(16):71007106.

19. Campestrini P, et al. Relation between microstructure and electrochemistry of AA5083 in marine environments. Corrosion Science. 2000;42(3):409428.

20. Ansari ALN, et al. Effect of welding parameters on the stress corrosion cracking of 5xxx series aluminum. Welding Journal. 2016;95:120S128S.

21. Pride ST, et al. The role of intermetallic particles in the localized corrosion of AA6061. Electrochimica Acta. 1994;39(8):10991104.

22. Enos DG, Taylor SR. The influence of seawater temperature on the pitting potential of marine aluminum alloys. Corrosion Science. 1996;38(11):18231834.

23. Sastri VS. Green Corrosion Inhibitors: Theory and Practice. Wiley; 2011.

24. Wang Y, Chen S. Plasma electrolytic oxidation of 6xxx series aluminum for marine applications. Applied Surface Science. 2016;385:411420.

25. Amin MA, et al. Environmentally friendly corrosion inhibitors for aluminum in natural seawater. Journal of Cleaner Production. 2016;112:24042415.

26. Kelly RG, et al. Electrochemical Techniques in Corrosion Science and Engineering. Marcel Dekker; 2002.

27. Li W, et al. Tribocorrosion behavior of marine grade aluminum alloys in artificial seawater. Tribology International. 2015;91:222230.

28. Melchers RE. Predictive modeling of marine corrosion of aluminum alloys: A data-driven approach. Ocean Engineering. 2014;84:4352.

29. Vargel C. Corrosion of Aluminium. 2nd ed. Elsevier; 2020.

30. Wharton JA, et al. The corrosion of marine aluminum alloys in deep-sea environments. Corrosion Science. 2005;47(10):24862500.

31. Yasakau KA, et al. Mechanism of galvanic corrosion between aluminum alloys and carbon steel in maritime structures. Materials and Corrosion. 2017;68(1):101112.

32. Taylor EJ, et al. Impressed current cathodic protection for aluminum vessel hulls. Marine Technology. 2005;42(2):9199.

33. Ahmad Z. Principles of Corrosion Engineering and Corrosion Control. Butterworth-Heinemann; 2006.

34. Fontana MG. Corrosion Engineering. 3rd ed. McGraw-Hill; 2005.

35. Machine learning approaches for corrosion prediction and materials durability. npj Materials Degradation. 2022.

36. Lynn TR, et al. Erosion-corrosion of aluminum alloys in fast flowing seawater. Wear. 2009;267(14):195202.

37. Little DA, et al. Microbiologically influenced corrosion of aluminum alloys in marine environments. Biofouling. 2007;23(4):253261.

38. Huang CH, et al. Enhancement of anodized oxide films on AA5083 for prolonged marine exposure. Surface and Coatings Technology. 2008;202(15):36723680.

39. Lyon SB, et al. Next-generation hybrid organic-inorganic corrosion resistant coatings. Progress in Organic Coatings. 2017;102:96105.

40. Recent developments in plasma electrolytic oxidation coatings on aluminum alloys. Surface and Coatings Technology. 2021.

41. Chen X, Li Y, Wang Z. Advanced graphene oxide reinforced epoxy coatings for marine aluminum alloy protection. Progress in Organic Coatings. 2023;176:107381.

42. Kumar A, Singh R, Gupta P. Recent progress in eco-friendly corrosion inhibitors for aluminum alloys in seawater applications. Journal of Cleaner Production. 2022;350:131419.

43. Zhao H, Liu J, Chen W. Plasma electrolytic oxidation coatings on AA6061 aluminum alloy for marine environments. Surface and Coatings Technology. 2021;405:126673.

44. Wang T, Zhou Y, Li Q. Corrosion fatigue behavior of marine-grade aluminum alloys under cyclic seawater exposure. Corrosion Science. 2020;170:108689.

45. Ahmed S, Hassan M, El-Sayed A. Electrochemical investigation of pitting corrosion in AA5083 aluminum alloy using EIS techniques. Electrochimica Acta. 2021;389:138741.

46. Ferreira MGS, Zheludkevich ML. Smart nanocontainer coatings for active corrosion protection of aluminum alloys. Surface and Coatings Technology. 2020;392:125743.

47. Gupta RK, Birbilis N. Recent advances in localized corrosion mechanisms of aluminum alloys. Current Opinion in Solid State and Materials Science. 2022;26(5):100987.

48. Li J, Zhang H, Xu D. Hybrid sol-gel coatings for corrosion protection of marine aluminum structures. Progress in Organic Coatings. 2021;158:106349.

49. Yang Y, Chen X, Huang L. Machine learning assisted prediction of corrosion behavior in marine aluminum alloys. npj Materials Degradation. 2023;7:41.

50. Wang P, Liu Y, Zhao T. Tribocorrosion mechanisms of aluminum alloys in artificial seawater environments. Tribology International. 2021;162:107127.

51. Shi Z, Atrens A. Stress corrosion cracking mechanisms in high-magnesium aluminum alloys: A review. Corrosion Science. 2019;157:89105.

52. Lee S, Kim H, Park J. Corrosion performance of anodized AA5083 aluminum alloy in chloride-rich marine conditions. Applied Surface Science. 2020;512:145759.

53. Zhang Y, Wu G, Li H. Self-healing polymeric coatings containing microcapsules for aluminum corrosion protection. Chemical Engineering Journal. 2022;428:131176.

54. Liu X, Zhao Y, Wang H. Comparative study of cathodic protection systems for marine aluminum structures. Marine Structures. 2021;78:102977.

55. Chen L, Xu W, Huang Z. Corrosion behavior of friction stir welded AA5083 aluminum alloy in seawater. Materials and Design. 2020;192:108716.

56. Ralston KD, Birbilis N. Effect of alloy microstructure on the corrosion of aluminum alloys in marine environments. Corrosion. 2018;74(4):451466.

57. He J, Wang Q, Zhang X. Nanostructured ceramic coatings for tribocorrosion resistance of marine aluminum alloys. Wear. 2022;488-489:204144.

58. Xu F, Li C, Zhou M. Influence of biofouling on corrosion degradation of marine aluminum alloys. Biofouling. 2021;37(6):655669.

59. Tang Y, Liu Z, Sun D. Graphene-enhanced epoxy coatings with superior barrier properties for marine applications. Progress in Organic Coatings. 2022;165:106768.

60. Patel R, Kumar V, Singh S. Sustainable waterborne coatings for corrosion protection of aluminum alloys in marine environments. Journal of Cleaner Production. 2023;382:135211.