Excellent Corrosion Resistance Research Articles

Surface modification of biomedical titanium alloy for hard tissue repair and reconstruction

In biomedical applications, various materials are used, including metals and their alloys, polymers and ceramics. Among them, titanium (Ti) and titanium alloys are widely utilised in implant materials due to their excellent corrosion resistance and high mechanical strength. However, despite these advantages, titanium is biologically inert and does not integrate well with human cells. Therefore, surface modification of titanium implants plays a crucial role in determining the rate of osseointegration and the overall success of the implants. The primary objective of this review is to provide a detailed introduction to surface modification technologies for titanium alloy implants. The aim is to enhance the biological activity, wear resistance, corrosion resistance and antibacterial properties and reduce the release of ions from the implants. By modifying the surface of titanium implants, it is possible to create a more favourable environment for cell adhesion, proliferation and differentiation. Various techniques, such as physical methods (e.g. sandblasting, acid etching) and chemical methods (e.g. surface oxidation, plasma treatment) can be employed to modify the surface properties of titanium implants. These surface modification techniques can enhance the interaction between the implant and the surrounding biological environment, promoting osseointegration and improving the long-term stability of the implant. Additionally, surface modifications can help reduce the release of potentially harmful ions from the implant, minimise bacterial adhesion and improve the overall biocompatibility of the implant. In conclusion, surface modification of titanium alloy implants is a critical aspect of biomedical engineering. By improving the biocompatibility of titanium implants, these modifications contribute to the success and longevity of implants used in hard tissue repair and reconstruction.

Study on the corrosion performance of supersonic atmospheric plasma sprayed Cr3C2-NiCr coatings

Purpose Due to the harsh underground environment in coal mining, the surface of hydraulic support columns corrodes severely, resulting in significant economic losses. Therefore, a highly corrosion-resistant coatings is needed to extend the service life of the columns. Design/methodology/approach This study aims to compare the corrosion resistance of ST-Cr3C2-NiCr (sealed treatment Cr3C2-NiCr) coatings with industrially applied chromium plating. The corrosion failure mechanism of the coatings was investigated. Findings The results demonstrated that the ST-Cr3C2-NiCr coatings exhibited excellent corrosion resistance. After sealing treatment, the corrosion potential of Cr3C2-NiCr coatings was −0.215 V, and the corrosion current density of Cr3C2-NiCr coatings was lower than that of the plated parts. Practical implications ST-Cr3C2-NiCr coatings prepared by supersonic atmospheric plasma spraying could provide excellent corrosion resistance in the coal industry. Originality/value The low porosity and the presence of the NiCr phase were crucial factors contributing to the preferable corrosion resistance exhibited by the ST-Cr3C2-NiCr coatings. The corrosive process of the coatings involved layer-by-layer delamination of surface oxide film, sub-surface pitting, formation and degradation of sub-surface passive film, as well as severe block-like delamination.

The precipitation and corrosion behaviour of cast Al–Mg–(0.7, 1.3) Li–Cu alloys

Achieving the development of ultra-light Al–Li alloys with high strength and excellent corrosion resistance is always a challenge. In this study, the precipitation characteristics and electrochemical corrosion behaviours after isothermal aging of cast Al–Li alloys with two different Li contents were comparatively analysed. The results showed that the increase in Li content from 0.7 wt-% to 1.3 wt-% retarded the peak hardening and improved the Al–Li alloy hardness and strength by promoting the precipitation of the S′ (Al2CuMg) and T1 (Al2CuLi) phases. Besides, the galvanic coupling corrosion of the alloying element Cu with the aluminium matrix was reduced by more Li addition, thus improving the corrosion resistance of the alloy.

Exploring Flower-Structured Bifunctional VCu Layered Double Hydroxide and its Nanohybrid with g-C3N4for Electrochemical and Photoelectrochemical Seawater Electrolysis.

Seawater electrolysis holds great promise for sustainable green hydrogen generation, but its implementation is hindered by high energy consumption and electrode degradation. Two dimensional (2D) layered double hydroxide (LDH) exhibits remarkable stability, high catalytic activity, and excellent corrosion resistance in the harsh electrolytic environment. The synergistic effect between LDH and seawater ions enhances the oxygen evolution reaction, enabling efficient and sustainable green hydrogen generation. Here, we report a synthesis of low cost, novel 2D Vanadium Copper (VCu) LDH first time in the series of LDH's as a highly efficient bifunctional electrocatalyst. The electrochemical (EC) and photoelectrochemical (PEC) study of VCu LDH and VCu LDH/Graphite Carbon Nitride (g-C3N4) nanohybrid was performed in 0.5 M H2SO4 (acidic), 1 M KOH (basic), 0.5 M NaCl (artificial seawater), 0.5 M NaCl + 1 M KOH (artificial alkaline seawater), real seawater and 1 M KOH + real seawater (alkaline real seawater) electrolyte medium. It was found that VCu LDH shows a remarkable lower overpotential of 72 mV hydrogen evolution reaction (HER) and 254 mV oxygen evolution reaction (OER) at current density of 10 mA/cm2 under alkaline real seawater electrolysis exhibiting bifunctional activity and also showing better stability.

Improved Fog Collection on a Hybrid Surface with Acylated Cellulose Coating.

Fog collection serves as an efficient method to alleviate water scarcity in foggy, water-stressed regions. Recent research has focused on constructing a hybrid surface to enhance fog collection efficiency, with one approach being the prevention of liquid film formation at hydrophilic sites. Inspired by the desert beetle, a coating (10-MCC) made by partially acylating microcrystalline cellulose (MCC) exhibits hydrophilic sites alongside a hydrophobic skeleton enabling rapid droplet capture despite its overall hydrophobicity. The captured droplets quickly coalesce into a large droplet driven by the wetting gradient created by the hydrophobic backbone and hydrophilic sites. To achieve greater fog collection efficiency, a hydrophobic-superhydrophobic hybrid surface is formed by combining a coating of 10-MCC with a superhydrophobic surface. The construction of superhydrophobic surfaces typically involves creating a rough surface with a distinctive structure produced by the anodization technique and modifying it with stearic acid. The superhydrophobic surface exhibits excellent corrosion resistance and mechanical stability. Moreover, the hybrid surface shows high efficiency in fog collection, with a tested maximum efficiency of approximately 1.5092 g/cm2/h, 1.77 times that of the original Al sheets. The results demonstrate a remarkable enhancement in fog collection capacity. Furthermore, this work serves as an inspiration for the low-cost and innovative design of engineered surfaces for efficient fog collection.

Microstructure, Corrosion and Mechanical Properties of Medium-Thick 6061-T6 Alloy/T2 Pure Cu Dissimilar Joints Produced by Double Side Friction Stir Z Shape Lap-Butt Welding

A novel double side friction stir Z shape lap-butt welding (DS-FSZW) process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar joints. The influence of welding parameters on weld microstructure and properties of DS-FSZW joint were systematically investigated. It indicated that defect-free medium-thick Al/Cu DS-FSZW joint could be achieved under an optimal welding parameter. DS-FSZW joint was prone to form void defects in the bottom of the second-pass weld. The recrystallization mechanisms at the top and middle of the weld nugget zone (WNZ) were continuous dynamic recrystallization (CDRX) and geometric dynamic recrystallization (GDRX). While the major recrystallization mechanism at the bottom of the WNZ was GDRX. DS-FSZW joint of the optimal welding condition with 850 r/min-400 mm/min was produced with a continuous thin and crack-free IMCs layer at the Al/Cu interface, and the maximum tensile strength of this joint is 160.57 MPa, which is equivalent to 65.54% of pure Cu base material. Moreover, the corrosion resistance of Al/Cu DS-FSZW joints also achieved its maximum value at the optimal welding parameter of 850 r/min-400 mm/min. It demonstrates that the DS-FSZW process can simultaneously produce medium-thick Al/Cu joints with excellent mechanical performance and corrosion resistance.

One-step hydrothermal preparation of corrosion-resistant coatings with microsphere structure

Rapid corrosion rate is limiting the engineering application of magnesium alloys. In this paper, an attempt was made to produce a corrosion resistant coating on the surface of AZ91D magnesium alloy using hydrothermal method. The coating surface is covered with microspheres and has a dense structure, which effectively isolates the contact between the outside world and the substrate. The corrosion potential(E) raised from −1.57 V to −0.45 V compared to the bare sample. The corrosion current density and corrosion rate of the coating can be reduced by 6 orders of magnitude, and the polarization resistance raised by 6 orders of magnitude. The thickness of the coating is 45.4 μm at the moment, with a minimum of defects on the surface, resulting in excellent corrosion resistance in the immersion test. The coating also has good adhesion strength at 4B, which can expand the application range of magnesium alloy in corrosive environments.

Study on the effects of nano-copper addition on the properties of epoxy resin/graphite composite bipolar plates

Bipolar plates (BPs) are vital components in Proton Exchange Membrane Fuel Cells (PEMFCs), and their performance and cost significantly impact fuel cell stack efficiency and affordability. BPs require excellent conductivity, strength, and corrosion resistance depending on usage conditions. Common graphite and metal-based BPs offer good conductivity, but they have their drawbacks. Graphite lacks strength and is costly to process, while metal-based BPs need additional surface treatments to prevent corrosion. In recent years, composite bipolar plates have gained widespread attention due to their excellent conductivity, mechanical properties, and outstanding corrosion resistance. In this study, we used natural graphite flakes as the main conductive filler and nano-copper as the secondary conductive filler, with epoxy resin as the binder. The composite bipolar plate was prepared using a hot-pressing method. The study found that adding 1 wt% of nmCu can increase the conductivity of the composite BP by 75.2%, but it decreases the flexural strength by 26.84%. The prepared nmCu/G/EP composite BP exhibits an ASR of only 4.00 mΩ cm2 and a corrosion current density of 2.615 × 10−7 A/cm2, meeting the DOE 2025 expectations. After conducting Cu2+ leaching experiments on the prepared composite BP, single-cell performance testing showed a maximum power density of 0.556 W/cm2. This study expands the range of conductive fillers for composite BPs, no longer limited to carbon-based conductive fillers.

Study on the properties of Ni-W-CrN thin films on X80 pipeline steel: Effect of current density and deposition time

X80 pipeline steel, an essential material for oil and gas pipelines, faces challenges in maintaining its integrity due to internal friction and exposure to corrosive environments. Addressing this issue, our study utilized electrodeposition to create a nano Ni-W-CrN composite protective coating on its surface for the first time, enhancing resistance to such wear and corrosion. The results indicate that the film prepared under a current density of 3 A dm−2 and deposition time of 60 min exhibits the finest structure, with a smooth surface, and an average thickness of 35 μm. The microcrystalline size ranges in the 8–15 nm range and the maximum hardness of 813 HV. Under these conditions, the lowest wear rate achieved was 1.16 mm3 (N m)−1. Electrochemical measurements show that the corrosion current density reached a minimum of 6.14 × 10−7 A dm−2, indicating excellent corrosion resistance. Simultaneously, the ratio of microhardness to Young's modulus (H3/E2) reached a maximum of 0.051, indicating the film's optimal resistance to deformation. This provides significant support for the fabrication of high-performance films on the surface of X80 pipeline steel.

On the use of aluminium alloys in sustainable design, construction, and rehabilitation of bridges: emerging applications and future opportunities

Over the last few decades, aluminium alloys have been widely used as primary structural material in building construction. This is due to their advantageous properties such as low density, high strength-to-weight ratio, durability and excellent corrosion resistance, and high recyclability. The scope of this review paper is to explore the potential use of aluminium alloys in bridge design and construction. To this end, a thorough discussion of the material properties is presented to identify if the aluminium alloys can meet the bridge design and construction requirements. Particular emphasis is also given on total life-cycle cost of aluminum alloys and their potential role towards sustainability and decarbonisation of bridge structures. Moreover, the possibility of using aluminium alloys as an alternative for bridge rehabilitation and strengthening is investigated herein. A review of the existing research on the static, dynamic and fatigue structural response of aluminium bridge decks is also conducted. The main findings are highlighted, and research gaps are identified. Finally, corresponding future research to fill these gaps is recommended.

High anti-corrosive and Scalable CDs/BCN heterostructure photocatalysts for efficient H2 production in natural seawater

Photocatalytic natural seawater-derived splitting to produce hydrogen is one of the most potential strategies to alleviate the shortage of freshwater resources and energy crisis. Nevertheless, the complicated composition of natural seawater poses substantial challenges to the activity and stability of photocatalysts. Here, we report on the fabrication of carbon dots (CDs) and B elements co-modified carbon nitride (i.e. CDs/BCN) via precursor-mediated supramolecular self-assembly and subsequent NaBH4-assisted thermal reduction as well as its implementation as seawater-derived H2 production. The fabricated CDs/BCN exhibits the flaky porous structure capable of providing more transport channels for the generated gases (e.g. H2) and precipitates (e.g. Mg(OH)2, Ca(OH)2) during the seawater splitting process. Benefitting from cooperation of CDs and B elements i.e. the inhibited recombination of electron-hole pairs as well as the extended optical absorption range of CN, the optimal CDs/BCN-2 under visible-light irradiation exhibits the high H2 production rate up to 10369 μmol g-1 h-1 in natural seawater. The proven satisfactory reusability and the corresponding structural stability demonstrate the excellent corrosion resistance of CDs/BCN-2 in natural seawater. Additionally, CDs/BCN-20 photocatalyst synthesized via 20-fold precursor amplification procedure still displays efficient photocatalytic performance of 9022 μmol g-1 h-1, indicating its potential for industrial applications.

Hot deformation, processing maps, and microstructural evolution of Ti/Ni/Ti layered composites

Ti/Ni/Ti layered composites, which combine the advantages of Ti and Ni, are widely used in sensor and biomedical applications due to their light weight, high strength, high conductivity, good stability and excellent corrosion resistance. However, it is difficult to control the structural parameters, microstructure, and mechanical properties of layered composites during co-deformation processing due to the distinct differences in the crystal structure, mechanical properties, and deformation behavior of Ti and Ni layers. In this paper, the hot deformation, processing maps, and microstructural evolution of Ti/Ni/Ti layered composites during hot deformation processing are investigated through hot compression tests at 550–850 °C/0.001–1.0 s−1, with a reduction of 65%. It is shown that the composites exhibit mainly dynamic recovery or similar dynamic recrystallization characteristics. Combined with the interface structure, processing maps and microstructure, the optimal parameters for Ti/Ni/Ti layered composites are 680–730 °C/0.007–0.015 s−1. During co-deformation, the microstructural evolution of the constituent layers is very complex. The deformation mechanism is mainly dynamic recovery (DRV), or DRV and dynamic recrystallization (DRX) in Ti layer, and work hardening (WH) or DRV in Ni layer.

Numerical and experimental studies on bending behavior of circular aluminium-concrete-steel double skin tubular cross-sections and bending capacity design approach

Considering the excellent corrosion resistance of aluminium alloy, a new-type aluminium-concrete-steel double skin tubular (ACSDST) member is proposed by replacing the outer steel tube of concrete-filled double skin steel tubular members with an aluminium alloy tube to improve structures' corrosion resistance and durability. Until now, no literature has been available on ACSDST cross-section in bending. This paper presents experimental and numerical investigations on the flexural behaviour of circular ACSDST cross-sections in bending. Broad parameters are examined in this research, including varying diameter-to-thickness ratios of the outer tube (20–120), hollow ratio (0.2–0.75), concrete compressive strength (30–70 MPa) and steel yield strength (235–355 MPa). The experimental results show that the final failure is controlled by the tensile rupture of aluminium alloy tubes, but it generally happens after the maximum moment, and the composite section behaves in good curvature ductility. The parametric analysis based on the developed finite element (FE) model discloses the different influences of diameter-to-thickness ratios of the outer tube, hollow ratio, and concrete and steel strengths on the bending moment capacity. Among them, the diameter-to-thickness ratio of the outer tube and hollow ratio significantly affect the bending moment capacity. The design equations for bending moment capacity are induced based on the plastic stress distribution method. Those equations are safe and accurate for the maximum moment (a widely used definition of bending moment capacity) within a certain range of parameters. However, a reduction factor 0.9 is proposed for the equations to predict the moment at a longitudinal flexural tensile strain of 1% (another widely used definition of bending moment capacity). Moreover, the cross-section slenderness limit for the compact ACSDST section is recommended based on the analysis of the experimental and FE results.

Impact of surfactant groups on the corrosion inhibition properties of superhydrophobic membranes on X80 steel

Fe2O3/Fe3O4 composite films were successfully prepared on the surface of X80 steel through hydrothermal synthesis and annealing treatments. Subsequently, the oxidised films were modified using surfactants such as decanoic acid (DA), decyl silane triol (DS) and perfluorodecyl silane triol (FDS), resulting in the creation of three distinct films exhibiting superhydrophobic properties. The effects of the hydrophilic and hydrophobic groups of surfactants on the superhydrophobic films of X80 steel were analysed using electrochemical methods, surface analysis techniques and theoretical calculations. The results showed that all three superhydrophobic films exhibited excellent corrosion resistance, with the order being DA > FDS > DS after 72 h of immersion in acidic conditions (pH = 6, 60 °C). Theoretical calculations showed that the adsorption performance of carboxyl groups was superior to that of silyl alcohol bonds, whereas fluorination of hydrophobic groups helped to enhance the adsorption capacity of hydrophilic groups. This not only reveals the key role of surfactants in the preparation of superhydrophobic membranes but also provides a theoretical basis for the preparation of superhydrophobic membranes on carbon steel surfaces.

Friction and Wear Behavior of Selective Laser Melted Ti6Al4V-Equine Bone Nanocomposites

Ti6Al4V is commonly used in implants because of its excellent mechanical properties, corrosion resistance, and biocompatibility. While Hydroxyapatite (HAp) is typically used for strong biological bonding between Ti6Al4V implants and bone tissue, this study takes a different approach by incorporating Equine Bone (EB), which has a chemical structure similar to human bone tissue, as a substitute for HAp. In this study, to develop implant materials with a low elastic modulus, high strength, and excellent wear resistance, Ti6Al4V used in biomedical applications was combined with natural EB. Subsequently, a Ti6Al4V-0.05EB composite was fabricated using ball milling followed by Selective Laser Melting (SLM). SLM can reproduce even the interior of a 3D structure, so various studies are being conducted to apply it as a biomaterial. However, Ti6Al4V alloys produced by SLM are known to have low ductility due to localized heat gradients, rapid solidification, and cooling rates. This reduced ductility can result in decreased formability of biomaterials, and the high elastic modulus may lead to stress shielding phenomena, potentially reducing the lifespan of the biomaterial. To minimize this, a post-heat treatment was applied to the Ti6Al4V-0.05EB composite material manufactured by SLM. Afterwards, the microstructure, mechanical properties, and wear resistance, which are important in biomaterials, were evaluated.

Preparation and performance study of highly durable silicone rubber superhydrophobic surfaces

Superhydrophobic coatings are widely applied in aerospace and other fields to address issues such as surface drag reduction, anti-icing, and corrosion resistance. Due to the poor durability and unstable performance encountered in the application of most superhydrophobic coatings, we have combined the template method with the spray method to prepare a superhydrophobic surface with excellent durability. Experimental results demonstrate that the contact angle and sliding angle of the prepared surface reached 160.9° and 2.5°, respectively. Importantly, even after undergoing tests such as high-load sandpaper abrasion, tape peeling, and high-speed steel ball impact, the surface maintained outstanding hydrophobic performance. Furthermore, the surface exhibited not only excellent chemical corrosion resistance and self-cleaning effects but also, after experiencing high-load mechanical wear, extended the ice formation delay time to 201 seconds compared to a silicone rubber surface. This study employed a simple and environmentally friendly preparation process, providing robust guidance for the theoretical analysis and practical operation of designing and preparing superhydrophobic surfaces with outstanding durability.

Efficient dual defense: PDA-Cu coating for simultaneous corrosion resistance and antibacterial protection of Mg alloys

The corrosion problem of Mg alloys remains a significant barrier to their technical applications. Particularly challenging is meeting specific functional requirements while enhancing corrosion resistance. Here, a novel metal organic composite coating (PDA-Cu) has been developed, exhibiting excellent corrosion resistance, strong bonding strength, and potent antibacterial properties. In 3.5 wt% NaCl solution, the corrosion rate of PDA-Cu alloy was significantly lower than that of bare Mg alloy, about 1/360; it had a strong inhibition rate (100%) and high binding strength (23.75 N). Importantly, the composite coating maintains consistency across various substrates and forms, proving its adaptability and expanding its potential applications.

Surface modified molybdenum disulfide nanosheets for corrosion resistance improvement on polyurethane coatings

Abstract Organic–inorganic hybrid coating has been applied on metallic corrosion protection effectively. Molybdenum disulfide (MoS2) nanosheets with graphene-like two-dimensional lamellar structure were an anticorrosion inorganic additive, rendering the organic coating better corrosion resistant. However, the aggregation and poor solubility are still current issues that should be addressed. Functionalization MoS2 nanosheets with surface modified by polydopamine (PDA) and silane coupling agent (KH560) were prepared in polyurethane (PU) composite coatings to obtain dense and intact multilayer network structure coatings for corrosion protection. KH560-PDA-MoS2/PU coating with crosslinked polymer network structure has a high impedance modulus, large contact angle, and strong hydrophobicity. The coating meets the national technical standards for salt spray testing and nitric acid (HNO3) titration testing, demonstrating excellent corrosion resistance.

The Effects of B on the Microstructure and Corrosion Resistance of Zn–6Al–3Mg Alloy Coating

Hot dip galvanized zinc‐aluminum‐magnesium steel plates are widely used in fields such as power communication, automotive manufacturing, and marine engineering due to their excellent corrosion resistance. The use of microalloying can further improve their corrosion resistance. The effects of B on the microstructure and corrosion resistance of Zn–6Al–3Mg (ZAM) alloy coatings are systematically examined. Data indicates that the eutectic structure of the coating progressively refines as B content increases, concomitant with a reduction in the thickness of the Fe2Al5 inhibition layer owing to the augmented formation of an Al‐rich phase at the surface. When the addition of B reaches 0.12%, the microstructure of the alloy coating is minimized, and there is no further reduction in the thickness of the Fe2Al5 inhibition layer. Moreover, the presence of B diminishes the corrosion current density and bolsters corrosion resistance. Optimal corrosion performance, indicated by maximal density and uniformity of surface corrosion products and the lowest corrosion current density, is achieved at a B addition of 0.12%. The judicious selection of B content is pivotal for enhancing the microstructural and anti‐corrosive properties of ZAM alloy coatings. Therefore, adding 0.12% B to ZAM alloy can effectively improve the microstructure and corrosion resistance of the alloy coating.

Multifunctional superhydrophobic coatings with self-cleaning and anti-fouling properties for corrosion protection of metals

Superhydrophobic coatings have self-cleaning, antifouling, and anti-corrosion properties due to their unique surface properties, but their disadvantages such as poor durability, poor mechanical properties, and complicated preparation methods severely limit their practical applications. Here, superhydrophobic coatings with high abrasion resistance and long-lasting corrosion resistance were prepared by a simple spraying method using stearic acid-modified titanium dioxide nanoparticles (TiO2), polyphenylene sulfide (PPS) as the base material, and doped polyvinylidene difluoride (PVDF). The SA-TiO2 can provide low surface energy and rough structure, and the PPS itself has high mechanical strength and corrosion resistance properties. The PVDF doping can generate cross-linking inside the coating to improve the densification and mechanical strength of the coating, while the formation of irregular micrometer-sized protrusions can play a role in protecting the nano-surface. he synergistic effect of the various components results in an excellent mechanical stability of the coating, which remains superhydrophobic after a 400 cm sanding test. In addition, the coating has excellent corrosion resistance, and the electrochemical impedance spectroscopy (EIS) results show that the impedance modulus of the coating is as high as 21.99 kΩ·cm2. The coating has a hierarchical micro-nano structure, and shows excellent mechanical and corrosion resistance, which is of great potential for practical applications.