Marine Applications Research Articles

Characteristics performance evaluation of AZ91-fly ash composite developed by vacuum associated stir processing

ABSTRACT The AZ91 class magnesium alloy was familiar with automotive, aviation, and marine applications due to its uniqueness of being lightweight, high strength, good fracture toughness, better dynamic stability, and good castability behaviours. The novel research aims to enhance the AZ91 alloy composite by adapting fly ash (FA) nanoparticles as 0, 2.5, 5, 7.5, and 10 wt%, respectively, and made by using a vacuum liquid stir casting process under constant stir speed. Influences of FA on micro-structural, physical (density/porosity), mechanical (hardness, impact toughness, tensile stress) and corrosion behaviour of AZ91 alloy nanocomposite were investigated. The composite with 10 wt% FA exposed excellent particle dispersion, better Vickers hardness of 95.4HV, good toughness value of 20.6J/mm2, superior tensile stress of 276MPa, and least corrosion rate of 3.81 mm/year. The optimum characteristics of FANC4 (AZ91/10 wt% FA) are suggested for automotive structural (seat and roof frame) applications.

Design and performance evaluation of SEANet, a software-defined networking platform for the Internet of Underwater Things

This paper presents the design and performance evaluation of the SEANet platform, a software-defined acoustic modem designed for enhancing underwater networking and Internet of Underwater Things (IoUT) applications. Addressing the limitations of traditional acoustic modems, which suffer from low data rates and rigid architectures, SEANet introduces a versatile, adaptive framework capable of reconfiguring all layers of the protocol stack in real-time to accommodate diverse marine applications. The platform integrates high-performance, wideband data converters with modular hardware and software components, enabling real-time adaptation to changing environmental and operational conditions. Experimental evaluations conducted in oceanic settings demonstrate the SEANet capability to significantly exceed the performance of existing commercial underwater modems, supporting data rates up to 150 kbit/s and effectively doubling the performance metrics of conventional systems. Our robust testing also highlights the SEANet proficiency in channel estimation, Orthogonal Frequency-Division Multiplexing (OFDM) link establishment, and interoperability through the JANUS communication standard. Our results underscore the SEANet potential to transform underwater communication technologies, providing a scalable and efficient solution that supports high data rate applications and fosters the expansion of IoUT deployments.

Study of Effects on Performances and Emissions of a Large Marine Diesel Engine Partially Fuelled with Biodiesel B20 and Methanol

The impact of fossil fuel utilisation in different combustion systems on climate change due to greenhouse gas accumulation in the atmosphere is rather evident. A part of these gases comes from the large engines used for propulsion in marine applications. In the continuous global effort made by engine manufacturers to mitigate this negative impact, one way is represented by the utilisation of alternative fuels such as biodiesel and methanol, based on dedicated research to fulfil the more stringent regulations concerning pollutant emissions issued by piston heat engines. In this study, a numerical investigation was conducted on a four-stroke large marine diesel engine (ALCO 16V 251C) at several engine speeds and full load conditions. Different blends of diesel–methanol and biodiesel B20–methanol with methanol mass fractions of 10% and 20% were considered for theoretical analysis in two techniques of methanol supply: direct injection mode of a blend of base fuel diesel/biodiesel B20 with methanol and injection of methanol after the intercooler, and direct injection of the base fuel. The results show that, if 10% in power loss can be acceptable, then for diesel–methanol 10%, in the direct injection technology, the NOx emission can be reduced up to 19%, but with a compromise of an 8% increase in SOOT emission, while for biodiesel B20–methanol 10%, with the same direct injection method, the NOx emissions increase by up to 58% with the benefit of reducing SOOT by up to 23% relative to the original diesel fuel operation. For a 20% methanol fraction in blend fuel, the drop in power is more than 10% regardless of the method of methanol supply and the base fuel, diesel, or B20 used.

Effects of moisture absorption on penetration performance of FRP sandwich structures

Fiber-reinforced plastic sandwich structures (FRPSSs) are increasingly used in marine applications thanks to their high levels of stiffness, lightweight, buoyancy and damage resistance to penetration and impacts. This paper investigates the effect of exposure to seawater conditions on mechanical behavior of FRPSSs with various core configurations loaded with indenters with different geometries. A new in-situ acoustic emission (AE) methodology is applied to monitor the moisture evolution process, while X-ray micro-computed tomography validated its influence on out-of-plane failure modes observed in quasi-static indentation experiments. Results indicate that AE velocity can effectively monitor the moisture uptake, serving as an in situ structural health monitoring approach. It was also revealed that the core configuration had a limited effect on moisture ingress. Samples exposed to sharp indentation exhibited the greatest decrease in load-bearing capacity (in excess of 50% in some cases) while that for blunt indentation was the lowest. This can be explained by reduced penetration forces resulting from matrix plasticization and degraded matrix/fiber interface, exacerbated by a smaller contact area. Also, early damage initiation and intensified damage progression were observed for sharp indenters after the seawater exposure. The core of FRPSSs significantly influenced localized damage in samples indented with conical and flat indenters, unlike those subjected to hemispherical ones. The seawater exposure adversely affected the energy absorption and penetration performance, enhancing macroscale damage mechanisms. These findings offer valuable insights for design and optimization of FRPSSs for marine applications.

Mechanical characterization of mulberry silk reinforced hybrid composite for enhanced application

This research explores the effectiveness of two hybrid composites, pattern-1 (K-M-G-K-M-G-G-M-K) and pattern-2 (K-M-G-K-M-G-K-M-G), in experimental and simulation tests to create a cost-efficient hybrid composite. The composite includes Mulberry (M) silk (Bombyx mori) fibers reinforcing an epoxy resin-matrix hybrid with Kevlar (K) and Glass fiber (G). Both pattern-1 and pattern-2 are evaluated through experimental tests, and simulation tests are conducted to validate the findings. ANSYS Workbench is used for simulation tests to determine the best stacking sequence for protective gears, aerospace components, automotive parts, sport equipment and marine applications. The structural morphology of the hybrid composites is examined using scanning electron microscope (SEM). The results show that pattern-1 performs better than pattern-2 in various experimental and simulation tests, with a wider plastic zone in the tensile test stress-strain curve, greater tensile strength (73 MPa and 67.923 MPa), higher load-bearing capacity, and enhanced ductility. Pattern-1 also demonstrates improved performance in flexural strength (45.35 MPa and 71.474 MPa) and impact strength (6 J and 5.4898 J). Simulation results confirm that pattern-1 is superior to pattern-2 in terms of energy absorption and resistance to bullet penetration.

Geopolymer composites for marine application: Structural properties and durability

In marine environments, traditional ordinary Portland cement (OPC) and reinforced concrete structures are prone to corrosion, reducing their durability and service life dramatically. Geopolymers, with exceptional corrosion resistance, have great value and application potential in marine engineering. This paper presents a comprehensive overview of the research advances on geopolymer cements and concretes in marine environments in terms of mechanical properties, durability, and structural properties. The research so far has demonstrated that geopolymers exhibit superior mechanical properties and durability due to their denser interface and lower porosity compared to OPC. However, geopolymers have significant brittleness defects, and their performance in marine environments, especially in splash and tidal zones with alternating wet and dry conditions, is severely affected. This is due to the influence of chloride ions, divalent cations, pH, and sulfate in seawater, which promote or inhibit the formation and transformation of reaction products and microstructures, thereby affecting their mechanical properties and stability. Nevertheless, the use of composite technologies such as modified precursors, fibers, and nanomaterials has a positive effect on enhancing their structural properties and durability. This provides guidance and solutions for the application of high-durability, low-carbon emission, and more sustainable building materials in maritime engineering.

Enhanced antifouling and antibacterial performances of novel UV-curable polysiloxane/microcapsules/Ag composite coatings for marine applications.

Marine biological fouling is a widespread phenomenon encountered by various oceanic ships and naval vessels, resulting in enormous economic losses. Herein, novel 4,5-dichloro-2-octyl-isothiazolone@sodium alginate/chitosan microcapsules (DCOIT@ALG/CS) were prepared through composite gel method using DCOIT as core materials, ALG and CS as shells, and CaCl2 as the cross-linking agent. The formed microcapsules (MCs) with Ag nanoparticles (AgNPs) were then filled in UV-curable polysiloxane (UV-PDMS), followed by UV irradiation to yield UV-PDMS/microcapsules/AgNPs (UV-PDMS/MCs/Ag) composite coatings. The constructed micro-nano dual-scale surface using the MCs and AgNPs improved the antifouling and antibacterial properties of UV-PDMS/MCs/Ag coatings. The as-obtained UV-PDMS/MCs/Ag coatings exhibited a static contact angle of about 160°, shear strength of 2.24 MPa, tensile strength of 3.32 MPa and elongation at break of 212%. The synergistic bacteriostatic effects of DCOIT and AgNPs in UV-PDMS/MCs/Ag coatings resulted in a bactericidal rate of 200 μg ml-1 towards Escherichia coli and Staphylococcus aureus with saturation at 100% within 10 min. In sum, the proposed composite coatings look promising for future marine transportation, pipeline networks and undersea facilities.

Modelling guided energy management system for a hydrogen–fuelled harbour tug

The use of hydrogen as a source of fuel for marine applications is relatively nascent. As the maritime industry pivots to the use of alternate low and zero-emission fuels to adapt to a changing regulatory landscape, hydrogen energy needs to present and substantiate a technical and commercially viable use case to secure its value proposition in the future fuel mix. This paper leverages the technoeconomic and environmental assessment previously performed on HyForce, a hydrogen-fuelled harbour tug which has shown encouraging results for both technical and commercial aspects. This study aims to create a digital twin of HyForce to accurately predict her operability in real-world scenarios. The results from this study identify the strengths and drawbacks of the proposed use case. This is achieved by embedding the detailed design of HyForce in a virtual environment to further evaluate its operational performance through Computational Fluid Dynamics (CFD) simulations of realistic environmental conditions such as wind, wave, sea currents, and friction attributed to the properties of seawater. The results from this study indicate a base case power requirement of 93 kW to 1892 kW to achieve speeds of 5 to 12 knots in the absence of external environmental influences. Consequently, the speed of HyForce has a profound impact on total resistance peaking at 97.3 kN at 12 knots. Seawater properties such as low seawater temperature of 0 °C, and a high salinity of 50 g/kg increased friction. Additionally, wind speeds of 10 m/s acting on HyForce, delivered a resistance of 3 kN. However, these will be well mitigated through the design of the propulsion system which will be able to deliver a thrust power of 1892 kW and with assistance from the energy storage systems produce 2 MW of power to overcome the resistance experienced. The findings presented in this paper can serve as a foundation for constructing a robust model for the development of a predictive controller for future work. This controller has the potential to optimize the configuration of hydrogen and battery energy storage, aligning with desired cost functions.

Optimizing aluminum alloy performance for marine superstructures: Advanced nanocomposite coating for enhanced corrosion resistance, flame retardancy, and mechanical strength

Aluminium alloys find applications in the marine industry for boat hulls, ship superstructures, and offshore structures due to their corrosion resistance in marine environments. Nanocomposites incorporating impermeable two-dimensional materials hold a particular interest in safeguarding metals against corrosion. The introduction of 3-(m-aminophenoxy)propyltrimethoxysilane (APPMS) functionalized hafnium nitride (HfN) into a coating matrix can enhance the barrier effect owing to its exceptional chemical and thermal stability. Integrating functionalized HfN into graphitic carbon nitride (GCN) within polyurethane (PU) leads to improved corrosion protection and fire-retardant properties. Through electrochemical techniques in chloride environments, the protective efficacy of aluminum coated with polyurethane containing varying concentrations of functionalized HfN/GCN was investigated. The resulting PU with functionalized HfN/GCN composite demonstrates superior flame-retardant capabilities, with significant reductions in peak heat release rate (PHRR), total heat release (THR), and total smoke production (TSP) compared to pure PU. According to electrochemical impedance spectroscopy (EIS) measurements, PU/functionalized HfN/GCN exhibits enhanced coating resistance of 2.26×1010 Ω.cm2, even after 20 days of exposure to seawater. Featuring a water contact angle (WCA) of 161°, the newly developed PU/functionalized HfN/GCN coating displays exceptional water repellency. Moreover, PU/functionalized HfN/GCN demonstrates good mechanical properties in terms of adhesion strength and hardness within the PU substrate, enabling the coating to maintain its integrity even after prolonged immersion. The investigation presents a promising approach for developing advanced coatings tailored for marine applications, offering improved corrosion protection, fire resistance, water repellency, and mechanical durability. Thus, the PU/functionalized HfN/GCN nanocomposite shows promise as a viable coating component in marine applications.

Structure–property relationship assessment of dissimilar gas tungsten arc welded joint of pipeline steel and super duplex stainless steel for marine applications

Structure–property relationship assessment of dissimilar gas tungsten arc welded joint of pipeline steel and super duplex stainless steel for marine applications

Fatigue Evaluation of Sulphate-Attacked Industrial Waste-Based Concrete Using Concrete Damaged Plasticity Model

AbstractSulphate attack is a major cause of concrete deterioration in marine environments and its interaction with wave-induced cyclic loading exacerbates the damage. This study has evaluated strengths and fatigue performance (i.e. fatigue life, strain and residual displacement) of sulphate-attacked concrete containing silicomanganese slag, fly ash (FA) and silica fume (SF). Compressive strength, tensile strength and sulphate profile of sulphate-attacked concrete were measured experimentally. Sulphate-induced damage constitutive relations were formulated and used with concrete damaged plasticity (CDP) model to simulate fatigue loading. Experiment showed that incorporating silicomanganese slag lowered sulphate resistance by 4.8–6.6% due to increased sulphate intrusion, but synergy with FA and SF enhanced the resistance by 7.3–13.8% at 365 days. The sulphate penetration depth was 0–20 mm, and the intruded sulphate increased exponentially over time. To evaluate fatigue loading in CDP model, the non-uniform damage was determined as correlation between strength degradation and integral area of sulphate profile. Numerical results were in good agreement with experimental data from literature, with differences of 5.8–26.2% in fatigue life, 9.1–30.1% in fatigue strain and 18.1–41.9% in residual displacement. In long-term deterioration, numerical analysis found that increasing sulphate concentration significantly shortened fatigue life. Despite silicomanganese slag lowered concrete sulphate and fatigue resistance, the inclusion of FA and SF improved the durability and sustainability of concrete for potential marine applications.

Cocos nucifera-mediated electrochemical synthesis and coating of CuO/ZnO nanostructures on Fe ship strips for marine application

ABSTRACT Copper oxide and zinc oxide nanoparticles (Nanostructures) were synthesized using a greener electrochemical approach using Cocos nucifera (Coir) extract and deposited on Fe ship strip (FSS). These corrosion inhibitor films were characterized by XRD, SEM, BET, Raman Spectroscopy, FTIR spectroscopy, and TGA analysis. An electrochemical corrosion test was performed for the coated samples with 3.5% NaCl as electrolyte and compared with uncoated samples. The corrosion rate was tested using the Tafel slope and the interpolation between the log of current and voltage proves that the corrosion rate in the CuO-coated sample was lower than that of the ZnO-coated sample which can be attributed to the porosity of the ZnO film showing 0.8–0.95 P/P0 as observed for 6 cm2 as inferred from BET analysis. The Nyquist plot suggests the corrosion inhibition rate of the CuO-coated film in 3.5% NaCl is improved by a factor of 3 compared to the uncoated sample (0.9 mA/year for FSS where for the CuO-coated samples 0.3 mA/year). The result of the antifouling behavior of CuO/ZnO coatings using the BIOVIA simulation tool showed the repulsion of homology-modeled protein Aacp20k, an attachment protein found in Amphibalanus Amphitrite which is a most prominent foul species.

Effects of Seawater on Mechanical Performance of Composite Sandwich Structures: A Machine Learning Framework.

Sandwich structures made with fibre-reinforced plastics are commonly used in maritime vessels thanks to their high strength-to-weight ratios, corrosion resistance, and buoyancy. Understanding their mechanical performance after moisture uptake and the implications of moisture uptake for their structural integrity and safety within out-of-plane loading regimes is vital for material optimisation. The use of modern methods such as acoustic emission (AE) and machine learning (ML) could provide effective techniques for the assessment of mechanical behaviour and structural health monitoring. In this study, the AE features obtained from quasi-static indentation tests on sandwich structures made from E-glass fibre face sheets with polyvinyl chloride foam cores were employed. Time- and frequency-domain features were then used to capture the relevant information and patterns within the AE data. A k-means++ algorithm was utilized for clustering analysis, providing insights into the principal damage modes of the studied structures. Three ensemble learning algorithms were employed to develop a damage-prediction model for samples exposed and unexposed to seawater and were loaded with indenters of different geometries. The developed models effectively identified all damage modes for the various indenter geometries under different loading conditions with accuracy scores between 86.4 and 95.9%. This illustrates the significant potential of ML for the prediction of damage evolution in composite structures for marine applications.

Assessing the Antifouling Effectiveness of the Novel Organic Coating for Adherent Species in the Seawater of the coastal area of Ha Long City, Quang Ninh Province (Vietnam)

This paper presents the results of a 12-month testing period in seawater at Vung Oan, Ha Long City marine area, Quang Ninh Province (Vietnam), assessing the fouling organism’s removal effectiveness of polysiloxane (PS)/Ag-Zn zeolite/Cu2O nanocomposite coatings. This experiment is a substantial base to evaluate impact of Ag-Zn/zeolite and Cu2O nanoparticles (NPs) on growth of bacteria and macro-fouling organisms compared to a control coating without the above additives. The results indicated that the coating loaded with Ag-Zn/zeolite and Cu2O NPs exhibited a lower bacterial count than the coating without biocide additives. Specifically, the bacterial count was 9.6 × 105 for the coating with biocide and 2 × 107 for the coating without biocide. Regarding macro-fouling species, the analysis and identification of organisms attached to the coating samples revealed the presence of three fouling species: Perna viridis, Balanus amphitrite, and Haliclona cinerea. Modiolus barbatus, Nereis sp., and Xanthidae were only observed on surface of the control samples, suggesting that Ag-Zn/zeolite and Cu2O NPs can impede the development of Modiolus barbatus, Nereis sp., and Xanthidae on the coating surface. Furthermore, the average weight of macro-fouling organisms on the coating containing Ag-Zn/zeolite and Cu2O NPs was significantly lower (90 g/sample) than that of the macro-fouling organisms on the control coating (333 g/sample). Notably, one of the three samples with the Ag-Zn/zeolite and Cu2O NPs had the lowest weight of macro-fouling organisms, measuring only 35 g. Based on these findings, it can be concluded that polysiloxane/Ag-Zn/zeolite/Cu2O nanocomposite coatings show promise as antifouling paints for marine work applications.

Skill assessment of seasonal forecasts of ocean variables

There is growing demand for seasonal forecast products for marine applications. The availability of consistent and sufficiently long observational records of ocean variables permits the assessment of the spatial distribution of the skill of ocean variables from seasonal forecasts. Here we use state-of-the-art temporal records of sea surface temperature (SST), sea surface height (SSH) and upper 300m ocean heat content (OHC) to quantify the distribution of skill, up to 2 seasons ahead, of two operational seasonal forecasting systems contributing to the seasonal multi-model of the Copernicus Climate Change Services (C3S). This study presents the spatial distribution of the skill of the seasonal forecast ensemble mean in terms of anomaly correlation and root mean square error and compares it to the persistence and climatological benchmarks. The comparative assessment of the skill among variables sheds light on sources/limits of predictability at seasonal time scales, as well as the nature of model errors. Beyond these standard verification metrics, we also evaluate the ability of the models to represent the observed long-term trends. Results show that long-term trends contribute to the skill of seasonal forecasts. Although the forecasts capture the long-term trends in general, some regional aspects remain challenging. Part of these errors can be attributed to specific aspects of the ocean initialization, but others, such as the overestimation of the warming in the Eastern Pacific are also influenced by model error. Skill gains can be obtained by improving the trend representation in future forecasting systems. In the meantime, a forecast calibration procedure that corrects the linear trends can produce substantial skill gains. The results show that calibrated seasonal forecasts beat both the climatological and persistence benchmark almost at every location for all initial dates and lead times. Results demonstrate the value of the seasonal forecasts for marine applications and highlight the importance of representing the decadal variability and trends in ocean heat content and sea level.

An experimental investigation into the drag reduction performance of dimpled plates in a fully turbulent channel flow

Dimpled surfaces have gained increasing attention in recent years for their potential to reduce turbulent skin friction, a capability previously acknowledged for its beneficial implications on heat transfer. As a passive drag reduction method, dimpled surfaces offer significant advantages for marine applications due to their effectiveness and practical applicability. However, despite numerous studies, conflicting opinions and inconsistent drag reduction rates persist in the literature. This paper addresses these ambiguities and offers valuable insights into the effectiveness of dimpled surfaces for drag reduction in fully turbulent flows. We conducted an extensive experimental investigation involving various dimple configurations, including different depth-to-diameter ratios, diameters and orientations, utilising a specialised Fully Turbulent Flow Channel facility and a Particle Image Velocimetry system. Our findings demonstrated that circular dimple geometries, particularly those with low depth ratios, can achieve significant drag reduction of up to 27% as the Reynolds number increases. These results highlight the substantial potential of dimpled surfaces for improving energy efficiency in marine applications, where skin friction accounts for a significant portion of the total drag experienced by large vessels.

Accelerated seawater ageing and fatigue performance of glass fibre reinforced thermoplastic composites for marine and tidal energy applications

The use of thermoplastic composites as a sustainable alternative to thermosets is gaining increasing popularity due to their improved recyclability at the end of life. The fatigue performance of glass fibre/acrylic, glass fibre/acrylic- polyphenylene ether, and glass fibre/epoxy specimens, under three distinct upper stress levels (R-ratio = 0.1; f = 5 Hz) was studied. S–N curves were established for these specimens both before and after immersing them for three months in seawater (temperature: 50 °C). The dry thermoplastic composites exhibited similar fatigue performance to the thermoset counterpart at higher stress levels, with thermosets showing greater endurance at lower stress levels. Interestingly, the aged specimens showed comparable fatigue endurance, with a slight advantage in favour of the thermoplastic composites and less variability in their data. This study offers important insights into the fatigue performance of thermoplastic composites, emphasising their potential as sustainable alternatives to conventional thermoset composites for various marine applications.

Potential capacity and cost assessments for hydrogen production from marine sources

The current study comprehensively examines the application of wave, tidal and undersea current energy sources of Turkiye for green hydrogen fuel production and its cost analysis. The estimated potential capacity of each city in the country is derived from official data and acceptable assumptions and is subject to discussion and evaluation in the context of a viable hydrogen economy. According to the findings, the potential for green hydrogen generation in Turkiye is projected to be 7.33 million tons using a proton exchange membrane electrolyser (PEMEL). Cities with the highest hydrogen production capacities from marine applications are Mugla, Izmir, Antalya, and Canakkale with 998.10 kt, 840.31 kt, 605.46 kt, and 550.42 kt, respectively. The study calculations obviously show that there is a great potential by using excess power in producing hydrogen which will result in an economic value of 3.83 billion US dollars. This study further helps develop a detailed hydrogen map for every city in Turkiye, using the identified potential capacities of renewable energy sources and the utilization of electrolysers to make green hydrogen by green power. The potentials and specific capacities for every city are also highlighted. Furthermore, the study results are expected to provide clear guidance for government authorities and industries to utilize such a potential of renewable energy for investment and promote clean energy projects by further addressing concerns caused by the usage of carbon-based (fossil fuels dependent) energy options. Moreover, green hydrogen production and utilization in every sector will help achieve the national targets for a net zero economy and cope with international targets to achieve the United Nation's sustainable development goals.

Microstructure and electrochemical corrosion behavior of TA2 with nano/micro TiC particle reinforcement

TA2 pure titanium (Titan Grade 2-EN) is commonly used in marine and biomedical applications due to its outstanding biocompatibility and resistance to corrosion. Nevertheless, the limited hardness of TA2 presently reduces the service life of the components. Directed energy deposition (DED) technology can improve the properties of conformal materials, opening up new possibilities. In this work, 8% micro-TiC/TA2, 8% nano-TiC/TA2, and 4% micro/4% nano-TiC/TA2 composites were fabricated by DED to investigate the effects of different scales of TiC reinforcement on the properties of TA2. The majority of micro-TiC remaining unmelted in the composite, exhibiting only a small amount of micro-TiC dissolution. In comparison, the nano-TiC/TA2 displays a conspicuous dendritic structure with well-developed dendritic growth, boasting up to three dendrites. In contrast, the 4%micro/4%nano-TiC/TA2 exhibits a mixed crystal morphology, characterized predominantly by dendritic growth along the unmelted TiC, with other TiC phases also present in the deposited layer. Performance tests demonstrated that TiC can increase the microhardness of titanium. The 4% micro/4% nano-TiC/TA2 composite achieved the highest average microhardness of 542 HV0.2, representing a 160.58% increase compared to TA2. Additionally, the composites demonstrated improved corrosion resistance relative to TA2, with the 8% micro-TiC/TA2 composite exhibiting the best corrosion resistance. This outcome can be attributed to the effective physical barrier properties of the micron-sized TiC.

Environmentally friendly SLIPS coating based on flexible sponge: A novel approach to antifouling for ships

To mitigate the attachment of fouling organisms, Slippery Liquid-Infused Porous Surfaces (SLIPS) hold tremendous potential as a green and broad-spectrum antifouling solution, capable of replacing traditional antifouling coatings. However, the complexity of current preparation methods and the limited lifespan of lubricating oils constrain their widespread application in marine antifouling for vessels. In this study, melamine sponge (MS) was used as a substrate, and modifications were made by introducing superhydrophobic silica nanoparticles (SiO2 NPs), a biocompatible adhesive (ethyl cyanoacrylate, ECA), and a highly stretchable polymer (poly-ε-caprolactone, PCL). By combining natural surface microstructures with additional nanomaterials, we successfully obtained a superoleophilic surface, effectively capturing liquid lubricants and maintaining their long-term stability. The sponge substrate possesses distinctive contractility, with the lubricant stored in the grid spontaneously compensating for the loss of surface lubricant, thereby effectively enhancing its durability. This study provides a straightforward fabrication method with reduced manufacturing costs for environmentally friendly marine anti-fouling coatings. The approach demonstrates a prolonged cyclic anti-fouling effect, effectively advancing the development of SLIPS for anti-fouling applications in shallow marine environments.