Seawater Environment Research Articles

Research on the construction of gradient nanostructure and anti-tribocorrosion behavior of aluminum alloy surface

Gradient nanostructure in aluminum alloy, constructed via a two-dimensional ultrasonic surface burnishing process, displays enhanced tribocorrosion resistance in artificial seawater. Corrosion tests are undertaken to understand the influence of gradient nanostructure on corrosion resistance, and crystal plasticity finite element models are developed to examine wear resistance. Tribocorrosion tests are performed through wear tests in the artificial seawater environment. The results indicate that the processed samples' corrosion rate decreases from 3.12 × 10−2 mm/a to 2.45 × 10−3 mm/a. The wear scar sizes of the processed samples are approximately half the unprocessed samples. The gradient nanostructure obstructs dislocation glide during wear, diminishes the accumulation shear, and promotes high-hardness corrosion product formation, effectively isolating the direct contact between the friction pairs, thus improving the tribocorrosion resistance.

Enhancing Tensile Strength, Thermal Stability, and Antioxidant Characteristics of Transparent Kappa Carrageenan Films Using Grapefruit Essential Oil for Food Packaging Applications.

The trends in food packaging technologies are shifting toward utilizing natural and environmentally friendly materials prepared from biopolymers such as kappa carrageenan to replace synthetic polymers. In the current study, varying amounts (0.1, 0.2, and 0.3%) of grapefruit essential oil (GFO) were incorporated in kappa carrageenan-based edible films to improve their physicochemical properties. The developed film samples were characterized for their barrier, mechanical, morphological, optical, thermal, antioxidant, and biodegradable properties. The results obtained showed that the tensile strength of the carrageenan films enhanced significantly from 65.20 ± 4.71 to 98.21 ± 6.35 MPa with the incorporation of GFO in a concentration-dependent manner. FTIR and SEM analysis confirmed the intermolecular bonding between carrageenan and GFO, resulting in the formation of compact films. Incorporating GFO significantly enhanced the thermal resistance of oil-loaded films, as confirmed by TGA, DSC, and DTG analysis. The addition of GFO led to a substantial increase in the radical scavenging activity of the films, as evidenced by the DPPH and ABTS assays. Furthermore, the developed films were biodegradable in soil and seawater environments, indicating their potential as a sustainable alternative to traditional plastics. Findings demonstrated that GFO can be used as a natural antioxidant agent in kappa carrageenan-based films for potential applications in food packaging.

Marine domestication of Sporosarcina pasteurii induces the precipitation of CaCO3 to solidify calcareous sand

The construction of island reef projects using natural seawater, tailored to local conditions, holds significant importance for the advancement of environmentally-friendly geotechnical engineering practices. Previous studies on the application of MICP technology in a seawater environment have been scarce. In this study, Sporosarcina pasteurii were acclimatized to a seawater environment and employed for MICP mineralization reinforcement of calcareous sand, resulting in an enhanced mineralization effect compared to previous attempts under similar conditions. Both direct domestication and gradient domestication methods proved successful in enabling Sporosarcina pasteurii to adapt effectively within a seawater environment. Following domestication, the amount of CaCO3 generated through MICP solidification increased from 2.30% to 4.47%, resulting in a corresponding increase in the Ca2+ conversion rate from 5.19% to 10.02%. Additionally, after domestication, the unconfined compressive strength (UCS) reached up to 309kPa – representing an impressive improvement of 35.53% compared to pre-domestication levels, however, it should be noted that its reinforcement effect still falls short when compared with pure water conditions. The CaCO3 minerals formed after MICP reinforcement using seawater nutrient solution in domesticated Sporosarcina pasteurii predominantly consist of needle-shaped aragonite and granular anorthite minerals, as opposed to the previously observed calcite-type CaCO3 minerals.

Carbon Dioxide Corrosion Mechanisms: Historical Development and Key Parameters of CO2-H2O Systems

The recent failures in flexible pipes have motivated the exhaustive research of corrosion mechanisms on high-strength carbon steel armor wires that are the main structural compounds of those structures that mostly operate in seawater environments in the presence of carbon dioxide (CO2) and confined spaces. Recently, the literature reported discoveries about electrolyte properties (as Fe+2(aq)/HCO3-(aq.) ratio) and supersaturation, near neutral pH inside the confined space, multiphase reactions of contaminants present in CO2 gas, the formation and dissolution mechanism of FeCO3 film, and interaction of CO2 gas impurities with the corrosion scale. Therefore, this review is aimed at presenting an up-to-date narrative of the CO2 corrosion phenomenon in carbon steel, connecting background fundamentals with current data studies.

Blending Modification Technology of Insulation Materials for Deep Sea Optoelectronic Composite Cables

The insulation layer of deep-sea optoelectronic composite cables in direct contact with high-pressure and highly corrosive seawater is required for excellent water resistance, environmental stress cracking resistance (ESCR), and the ability to withstand high DC voltage. Although high-density polyethylene (HDPE) displays remarkable water resistance, it lacks sufficient resistance to environmental stress cracking (ESCR). This article is based on a blend modification approach to mixing HDPE with different vinyl copolymer materials (cPE-A and cPE-B). The processing performance and mechanical properties of the materials are evaluated through rheological and mechanical testing. The materials’ durability in working environments is assessed through ESCR tests and water resistance experiments. Ultimately, the direct current electrical performance of the materials is evaluated through tests measuring space charge distribution, direct current resistivity, and direct current breakdown strength. The results indicate that, in the polyethylene blend system, the rheological properties and ESCR characteristics of HDPE/cPE-A composite materials did not show significant improvement. Further incorporation of high melt index linear low-density polyethylene (LLDPE) material not only meets the requirements of extrusion processing but also exhibits a notable enhancement in ESCR performance. Meanwhile, copolymerized polyethylene cPE-B, with a more complex structure, proves effective in toughening HDPE materials. The material’s hardness significantly decreases, and when incorporating cPE-B at a level exceeding 20 phr, the composite materials achieve excellent ESCR performance. In a simulated seawater environment at 50 MPa, the water permeability of all co-modified composite materials remained below 0.16% after 120 h. The spatial charge distribution and direct current resistivity characteristics of the HDPE, cPE-A, and LLDPE composite systems surpassed those of the HDPE/cPE-B materials. However, the HDPE/cPE-B composite system exhibited superior dielectric strength. The application of composite materials in deep-sea electro–optical composite cables is highly promising.

Tailored nanocomposite FeNiB/MnO2/rGO@NF electrocatalyst for highly efficient and stable oxygen evolution reaction in freshwater and seawater environments

Efficient and stable electrocatalysts are of paramount importance for addressing the slow kinetics of the Oxygen Evolution Reaction (OER). In this study, we employ a robust strategy focusing on precise electronic modulation through nanocomposite structural engineering. FeNiB/MnO2/rGO@NF nanocomposites have been synthesized using a continuous hydrothermal method, with fine-tuned adjustments in the Ni/Fe ratio and boride content. The optimized composite, characterized by a Ni: Fe ratio of 2:1 and subjected to five boronization cycles, exhibited exceptional electrocatalytic performance in both alkaline freshwater (1.0 M KOH) and simular alkaline seawater (1.0 M KOH + 0.5 M NaCl). These materials achieved impressively low overpotentials of 266 mV and 276 mV to drive OER at 100 mA cm−2 in freshwater and seawater. Remarkably low Tafel slopes of 52.97 mV·dec−1 and 73.11 mV·dec−1 in alkaline freshwater and seawater, respectively, highlight their outstanding performance. The distinctive FeNiB/MnO2/rGO@NF composite amorphous structure emerges as a potent approach to fine-tune the catalyst's electronic configuration, significantly boosting OER performance. The incorporation of MnO2 within the rGO framework further mitigates agglomeration while creating additional catalytically active sites. This not only amplifies charge transfer capacity but also enhances overall electrochemical performance. The presence of nickel-iron boride renders the catalyst suitable for challenging seawater conditions, such as high salinity and corrosiveness. This study introduces a streamlined yet highly effective approach, offering a feasible and scalable route for crafting robust non-precious metal electrocatalysts tailored for OER applications in both freshwater and seawater environments.

Recent Advances for Seawater Hydrogen Evolution

AbstractHydrogen production from electrolysis of seawater is considered one of the most promising endeavors. However, the complexity of the seawater environment (corrosion‐prone, slow kinetics, and side reactions such as precipitation generation) leaves much room for progress in research on efficient and stable catalysts. In recent years, in order to improve the technology of hydrogen production from electrolytic seawater, scientists have focused on the preparation of catalysts and the design of electrolytes, which has resulted in important progress. In order to further understand the current research status and development prospects of seawater hydrogen evolution reaction (HER), this article summarizes the general design rules for electrocatalysts and electrolytes in seawater HER in recent years. For structure modulation, the effects of catalyst modulation strategies such as heterostructures, elemental doping, manufacturing defects, morphology engineering and others on performance enhancement are highlighted. Overall design guidelines are summarized for the electrolyte and directions for future in‐depth exploration are proposed with a view to the early realization of seawater hydrogen production on an industrial scale.

ZrP2O7/P-doped carbon: A pathway to enhanced 2e− ORR activity in seawater environments

Developing 2e− ORR catalysts that utilize seawater as an electrolyte is crucial for advancing energy storage technologies and controlling marine pollution. While non-metal-doped carbon materials demonstrate strong 2e− ORR performance in simulated seawater, enhancing their performance at high current densities and ensuring stability in actual seawater are major challenges. In this paper, a ZrP2O7/P-doped carbon (PC) composite catalyst was synthesized by a one-step sintering method, which exhibited a high FE% of 95.89 % in 0.5 M NaCl solution with an H2O2 yield of 3.52 mol g−1h−1, and also maintained an FE% of 83.79 % in real seawater. It was significantly better than PC (87.14 %, 3.20 mol g−1h−1 in 0.5 M NaCl, 68.15 %, 2.50 mol g−1h−1 in seawater). Experiments and theoretical calculations revealed the crucial role of ZrP2O7 in enhancing ORR performance. It facilitates proton transfer to the catalyst surface and impedes the accumulation of magnesium and calcium hydroxides on the electrode, enabling efficient H2O2 synthesis by the catalyst in real seawater under high current density.

Experimental Investigation into Lightweight High Strength Concrete with Shale and Clay Ceramsite for Offshore Structures

To develop lightweight high-strength concrete (LWHSC) for offshore structures in a harsh seawater environment, LWHSC with shale and clay ceramsites was designed. LWHSC was experimentally investigated in terms of density, compressive strength, and durability in a coastal environment. Then, its feasibility for offshore structures was also assessed. The results show that the compressive strength and oven dry density of LWHSC appropriately improve with increases in cement content, while they are reduced by the replacement of shale ceramsite with clay ceramsite. The compressive strength of LWHSC also increases first and then decreases with an increase in the pre-wetting of shale and clay ceramsites. Their optional pre-wetting time is about 0.5 h. LWHSC exhibits a higher brittleness compared with conventional concrete. LWHSC has increases in the resistances of freeze–thaw, carbonization, water penetration, and chloride penetration when the shale and clay ceramsite light aggregates decrease in the concrete. The LWHSC prepared in this paper is suitable for the harsh seawater environment of offshore oil platforms but is limited to the southern region where there is no requirement for the freeze–thaw resistance of concrete. The results of this study can provide some reference for the application of LWHSC in offshore structures and other similar aspects of engineering.

Nails as optimal source of DNA for molecular identification of 5 decomposed bodies recovered from seawater: from Y-ancestry to personal identification.

Molecular identification of extremely compromised human remains in forensic field is usually performed from DNA typing of bones, which are a difficult sample to work with. Moreover, autosomal STR profiles do not always result in the identification of the donor due to lack of comparisons or non-hit throughout database searching. An attempt to overcome these issues is represented by fingernails as an alternative DNA source and Y-STRs typing to infer both geographical and familial ancestry of the unknown donor. In this study, we analyzed both 24 autosomal and 27 Y-chromosome STRs from unidentified human remains (UHRs) of five males recovered from the water near the southwestern coast of Sardinia by the Italian Harbor Master's Office. Nail clippings provided an optimal source of autologous DNA for molecular identification in a very short time, producing complete autosomal and Y-STR profiles even under conditions of high body degradation. Unfortunately, no match neither compatibility occurred using autosomal STRs (aSTRs), initially. Upon analyzing the Y-haplotypes, we found out they had already been observed in northern Africa, providing us important investigative leads. This prompted the International Criminal Police Organization (INTERPOL) to provide us with references of alleged relatives that were then confirmed to be related. The use of fingernails represents an excellent DNA source especially for genetic identification of decomposed bodies recovered in seawater environment. Notably, DNA extracted from nails gave high-quality Y-STR haplotypes by which predicting paternal ancestry of the unidentified donors may result fundamental in the forensic investigative context.

Mechanism and evaluation method of stress corrosion susceptibility of 904L stainless steel with optimized structure in seawater

The stress corrosion cracking (SCC) and the electrochemical behavior of 904 L stainless steel in a simulated seawater environment were investigated using slow strain rate testing (SSRT), electrochemical polarization, electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) curves. The sensitive potential range of 904 L stainless steel was determined by the fast and slow scan potential polarization curve, is − 950 mVSCE ∼ 270 mVSCE. Moreover, with the negative shift of applied potential, the toughness fracture characteristic of the three kinds of steel is reduced, and the sensitization state steel is the most obvious reduction. Finally, a practical formula for evaluating the SCC susceptibility of 904 L stainless steel was developed by integrating data from SSRT and fast and slow scan polarization curves.

Mechanical, electrochemical corrosion, and high-temperature oxidation properties of stir-cast and heat-treated AZ80 magnesium alloy

This study aims to produce a stir-cast AZ80 magnesium alloy and to correlate the phases and microstructure of the as-cast, T4, and T6 conditions with the alloy's mechanical, corrosion, and oxidation properties. Microstructure was analysed using Field Emission Scanning Electron Microscopy (FE-SEM) with Energy Dispersive Spectroscopy (EDS), Electron Backscatter Diffraction (EBSD), and High-Resolution Transmission Electron Microscopy (HRTEM), and X-ray diffraction (XRD) technique was employed to examine at the alloy’s phases. A Vickers microhardness, tensile, and impact test specimens were meticulously prepared according to ASTM specifications. The electrochemical corrosion was tested in 0.6 M NaCl and 0.05 H2SO4, simulating the salty seawater and low-sulphur air environments. Based on the eutectic temperature of the Mg-Al alloy system, which is 437 ℃, the high-temperature oxidation test was carried out at 400 ℃, 410 ℃, and 420 ℃. Microstructural study confirms that both T4 and T6 alloys undergo grain coarsening with a grain size of 72.64 µm, and the orientation of the grains shifted from the pyramidal plane (2−1-10) to the basal plane (0001). The TEM investigation helps pinpoint the GP zone's genesis in T4 heat-treated AZ80. T4 AZ80 has a maximum ultimate tensile strength of 306 MPa and a ductility of 29.77% because of the dispersion-strengthening effect. The T6 AZ80, on the other hand, has a minimum corrosion rate of 0.158 mm/year in NaCl solution and an oxidation rate constant of 4.19 mg2.cm−4h−1 at 420 ⁰C. Notably, the T6 AZ80 shows significant peaks of Mg2Al3, and the as-cast shows more peaks of Mg17Al12. Magnesium alloy AZ80 is significantly affected by intermetallic phases like Mg17Al12 and Mg2Al3. The Mg2Al3 phase shows the latter tendency to resist corrosion and oxidation.

Design of amidoximized hydroxyapatite for extracting uranium from seawater

Extracting uranium from natural seawater is a huge challenge because of the complex environment of seawater and extremely low uranium concentration. In this work, amidoximized hydroxyapatite (AO-HAP) was prepared to capture uranium from seawater. The introduction of amidoxime group greatly improved the recognition ability of AO-HAP for uranium in neutral and weakly alkaline environment (pH = 7–8). The uptake process of AO-HAP for uranium was fitted by Langmuir and pseudo-second-order models, suggesting that the capture behavior of AO-HAP for uranium was a homogeneous chemisorption. The saturated uranium uptake capacity of AO-HAP was 865.3 mg g−1 from aqueous solution, which was better than most of other reported uranium extractants. More importantly, AO-HAP had good regeneration ability and excellent adsorption performance in natural seawater (6.25 mg g−1 in 30 days). In sum, AO-HAP is a highly potential candidate as adsorbent material for the efficient extraction of uranium from seawater.

Moisture diffusion analysis and their effects on the mechanical properties of organic particle filled natural fiber reinforced hybrid polymer composites

This investigation explores the water intake characteristics of hybrid composite samples composed of Wood Dust as organic filler (WD), Prosopis Juliflora as fiber (PJF), and epoxy as matrix. The specimens underwent immersion in both distilled and seawater environments for a duration of 240 hours. The composite samples, with compositions of 10WD + 30PJF + 60 PF, 20WD + 20PJF + 60 PF, and 30WD + 10PJF + 60 PF, were subjected to moisture content measurements at different intervals. Mechanical properties were tested following ASTM standards for both dry and wet conditions. Results indicate that seawater immersion leads to higher moisture absorption compared to distilled (condensed) water, with the fiber (PJF)-rich composite (30PJF +10WD + 60 PF) exhibiting the greatest water absorption. The water absorption pattern exhibited by the hybrid composite of WD/PJF/PF does not adhere to a Fickian behavior. Tensile, flexural, and impact properties were evaluated, with the (10WD + 30PJF + 60 PF) specimen showcasing superior performance in dry conditions, boasting a tensile character of 51 MPa, flexural (bending) strength of 60 MPa, and impact value of 1.4 KJ/m2. However, its strength diminishes upon exposure to distilled water and seawater. SEM analysis of fractured surfaces from seawater-exposed specimens provides additional insights. In conclusion, this study sheds light on the influence of immersion on moisture absorption and mechanical properties, emphasizing the prevalence of non-Fickian behavior and the varying performance of different compositions, with the (10WD + 30PJF + 60 PF) composition demonstrating remarkable strength under dry conditions.

Analysis of Nickel and Chrome Plating Temperature on Corrosion Rate of Steel in Seawater Environment

This study investigates the effect of Nickel and Chrome plating on ST 40 steel on corrosion resistance in a seawater environment. Several temperature variations were carried out during the chrome plating process, precisely at room temperature and 40℃, with a processing time of 5 seconds each and a voltage of 5 Volts. The Nickel plating was conducted with predetermined variables obtained from the initial research to achieve the most optimal results, especially the thickness of the plating formed. This process involves a temperature setting of 40℃, a processing time of 10 and 30 minutes, and a voltage of 5 Volts. To evaluate the results of this study, the corrosion testing was carried out using seawater corrosion media from 2 different beaches with 2.98% and 3.18% NaCl concentrations. In addition, microstructure testing is also conducted to determine changes in the structure of the base material after undergoing plating, and an optical microscope can be used to determine the thickness of the Nickel and Chrome layers. With Chrome plating at 40℃, the corrosion rate decreases compared to uncoated material in various seawater environments. The results emphasize that the plating process with the correct treatment can improve the corrosion resistance of steel, especially in seawater environments.

Examining the ability of palm kernel shell extract to control corrosion and assess its economic value on thermo-mechanically treated steel in artificial seawater: a sustainable and environmentally friendly approach.

Each year, the rising demand for palm oil generates large amounts of palm kernel shell waste. Discarded palm kernel shells can produce activated carbon, crushed shells, liquified fumes, and other derivatives; however, their indiscriminate disposal persists, raising issues related to the environment and economy. Therefore, the purpose of this study is to investigate the use of palm kernel shell as a corrosion inhibitor for thermo-mechanically treated steel in a seawater environment using gravimetric and electrochemical techniques, as well as surface tests at varying concentrations. The findings demonstrated that the palm kernel shell inhibited the cathodic and anodic processes by adsorption on the steel surface, which followed the Langmuir adsorption isotherm. The inhibitor exhibited a 98% inhibitory efficiency at 500ppm concentration. Scanning electron microscopy analysis verified the thin films of the inhibitor on steel surface in seawater solution. Fourier transform infrared spectroscopy results show that the extract's components prevent the steel corrosion through an adsorptive mechanism. According to the inhibitor economic evaluation, employing the palm kernel shell extract is less expensive than utilizing conventional inhibitors.

Accelerated Iron Corrosion by Microbial Consortia Enriched from Slime-like Precipitates from a Corroded Metal Apparatus Deployed in a Deep-sea Hydrothermal System.

Microbiologically influenced corrosion refers to the corrosion of metal materials caused or promoted by microorganisms. Although some novel iron-corrosive microorganisms have been discovered in various manmade and natural freshwater and seawater environments, microbiologically influenced corrosion in the deep sea has not been investigated in detail. In the present study, we collected slime-like precipitates composed of corrosion products and microbial communities from a geochemical reactor set on an artificial hydrothermal vent for 14.5 months, and conducted culture-dependent and -independent microbial community ana-lyses with corrosive activity measurements. After enrichment cultivation at 37, 50, and 70°C with zero-valent iron particles, some of the microbial consortia showed accelerated iron dissolution, which was approximately 10- to 50-fold higher than that of the abiotic control. In a comparative ana-lysis based on the corrosion acceleration ratio and amplicon sequencing of the 16S rRNA gene, three types of corrosion were estimated: the methanogen-induced type, methanogen-sulfate-reducing bacteria cooperative type, and sulfate-reducing Firmicutes-induced type. The methanogen-induced and methanogen-sulfate-reducing bacteria cooperative types were observed at 50°C, while the sulfate-reducing Firmicutes-induced type was noted at 37°C. The present results suggest the microbial components associated with microbiologically influenced corrosion in deep-sea hydrothermal systems, providing important insights for the development of future deep-sea resources with metal infrastructures.

Parameters as indicators of grounding rod corrosion in substation in port area

Grounding rods are an important component in electrical power to protect equipment from overvoltage and current disturbances. However, corrosion can cause a significant decrease in performance and reduce system efficiency. Therefore, the diagnosis of corrosion on grounding rods is important to ensure the reliability and continuity of substation operations. In this research, a corrosion structure diagnosis was done on the grounding rod in the Belawan Port area using COMSOL Multiphysics 5.3 software. The element method is used to model the electrochemical corrosion phenomena that occur in grounding rods. Corrosion-causing factor parameters such as soil resistance, pH, temperature, humidity, and salt content are measured and evaluated. The analysis results show that there is significant corrosion on the grounding rod, especially in areas exposed to sea water and corrosive environments. The potential distribution shows uneven potential along the grounding rod. Based on this research, additional maintenance and protection measures can be proposed to reduce the risk of corrosion and extend the life of grounding rod equipment. Based on the analysis results, the input parameters differentiate electrolyte reactions which further determine grounding rod.

Effects of seawater and acidic environment on mechanical properties of iron powder-loaded glass-epoxy composite laminates: Experimental and analytical investigation

This study assesses the impact of seawater and acidity on a glass epoxy composite filled with pure iron powder. Plates with varying iron content (15%, 20%, and 25%) were created using contact molding, with 30% glass fiber content. After dividing the plates into samples, a three-point bending examination was conducted following ISO14125 standards. The samples were immersed in saltwater (Group A), an acidic solution (Group B), or kept dry for comparison (Group C). Each subgroup had 15 specimens (5 for each iron %), immersed for over 60 days before undergoing bending tests. Results showed a significant decline in flexural strength, with a maximum reduction of 29.7% in Group A and 37.9% in Group B, while Young's modulus decreased up to 34.8% in Group A and 45.6% in Group B. The two-way ANOVA approach confirmed these findings, and microscopic examinations and FTIR analysis after immersion elucidated physical alterations and chemical reactions. Despite certain advantages, such as specific applications, the composite's limitations in corrosion resistance, durability, and production cost may restrict its relevance in various industrial and real-world applications. Consideration of these factors is essential before choosing this material for a specific project.

Effect of cathodic protection on the corrosion fatigue crack growth behavior and fatigue life of XS-grade shipbuilding steel

Shipbuilding steels are subjected to corrosion fatigue damage phenomena due to conjoint effects of cyclic loading by sea waves and corrosive seawater environment, which often leads to premature failure of ship hull structures. In practice, the impressed current cathodic protection (ICCP) technique is applied to mitigate ship hull corrosion by electrochemically making it cathodic. It is implemented by impressing a direct current to minimize the electrode potential to a predefined protection potential. It is significant to study the effect of ICCP on the corrosion fatigue crack growth rate (CFCGR) behavior and fatigue life assessment of ship hull structures. In this study, CFCGR behavior of high-strength XS-grade shipbuilding steel was investigated in unprotected freely corroding (FC) and protected ICCP (at – 800 mV) conditions using compact-tension specimens at 0.1 Hz frequency in artificial seawater (3.5 wt.% NaCl solution). After crack-closure corrections, it was found that the ICCP-protected specimen (∆KTH = 18 MPa √m) exhibited higher sub-critical or threshold corrosion fatigue crack propagation resistance as compared to the FC specimen (∆KTH = 14 MPa √m). Fractography of the FC specimen revealed the debonding of non-metallic inclusions and formation of micro-pits/secondary cracks as dominant damage mechanisms. ICCP-protected specimen exhibited a signature pattern of parallel secondary cracks and a proportional increase in their density with increasing stress intensity levels during primary crack growth. This fracture morphology indicated the primary-crack branching and further arrest, leading to retarded crack growth rates under ICCP-protection. Fatigue life analysis also confirmed this finding, where the beneficial ICCP-protection effect resulted in at least two times enhancement in fatigue lives from the unprotected FC condition.