Excellent Anti-corrosion Properties Research Articles

Epoxy Composite Coating with Excellent Anti-Corrosion and Self-Healing Properties Based on Acrylate Copolymers

Epoxy Composite Coating with Excellent Anti-Corrosion and Self-Healing Properties Based on Acrylate Copolymers

In-Situ Fabrication of Superhydrophobic Surface on Copper with Excellent Anti-Icing and Anti-Corrosion Properties

In-Situ Fabrication of Superhydrophobic Surface on Copper with Excellent Anti-Icing and Anti-Corrosion Properties

Slippery Surface with Petal-like Structure for Protecting Al Alloy: Anti-corrosion, Anti-fouling and Anti-icing

The harsh working environment affects the performance and usage life of Al and its alloys, thus limiting their application. In recent years, Slippery Liquid-infused Porous Surface (SLIPS) has attracted much attention due to excellent anti-corrosion, anti-fouling and anti-icing properties. This may be an effective way to improve the properties of Al and its alloys. Here, the SLIPS with petal-like structure was constructed on the Al alloy via simple hydrothermal reaction, Stearic Acid (STA) modification and lubricant injection. A variety of droplets (including oil-in-water emulsions) can slide on the SLIPS at a low angle, even the Sliding Angle (SA) of the water droplet is only 3°. Furthermore, the SLIPS exhibits outstanding mechanical and chemical properties. It can maintain fine oil-locking ability under high shearing force and keep slippery stability after immersion in acid/alkaline solutions. In addition, the SLIPS possesses excellent anti-corrosion, anti-fouling and anti-icing properties, which provides a new way to promote the application of Al and its alloys. Therefore, the SLIPS is expected to be an effective way to improve the properties of Al and its alloys, as well as play a role in anti-fouling and self-cleaning in construction, shipbuilding and automotive manufacturing industries, thereby expanding the practical application of Al and its alloys.

Aggressiveness of Different Ageing Conditions for Three Thick Marine Epoxy Systems

Three different coated steel systems were aged in natural or artificial seawater, in neutral salt spray (NSS), and using alternate immersion tests in order to evaluate the aggressiveness of the different ageing conditions. Commercial epoxy coatings were applied onto steel (S355NL), hot-galvanized steel (HDG), and Zn-Al15 thermal spraying coated steel. The defect-free systems were immersed in artificial seawater at 35 °C for 1085 days and in natural seawater for 1200 days and were characterized by electrochemical impedance spectroscopy (EIS). Panels with artificial defects were immersed for 180 days in artificial seawater and, regarding adhesion, were evaluated according to ISO 16276-2. In parallel, the three coated systems were submitted to cyclic neutral salt spray (NSS) for 1440 h: defect-free panels were regularly evaluated by EIS, while the degree or corrosion was measured onto panels with artificial defect. After NSS, defect-free panels were immersed in artificial seawater at 35 °C for further EIS investigations. Finally, alternate immersion tests were performed for 860 days for the three defect-free coated systems and for 84 days for panels with a defect. The results showed that, for defect-free panels, immersions in natural or artificial seawater and NSS did not allowed us to distinguish the three different systems that show excellent anticorrosion properties. However, during the alternate immersion test, the organic coating system applied onto HDG presented blisters, showing a greater sensitivity to this test than the two other systems. For panels with a defect, NSS allowed to age the coatings more rapidly than monotone conditions, and the coating system applied onto steel presented the highest degree of corrosion. Meanwhile, the coating systems applied onto HDG and the thermal spray metallic coating showed similar behavior. During the alternate immersion test, the three coated systems with a defect showed clearly different behaviors, therefore it was possible to rank the three systems. Finally, it appeared that the alternate immersion test was the most aggressive condition. It was then proposed that a realistic thermal cycling and an artificial defect are needed when performing ageing tests of thick marine organic coating systems in order to properly rank/evaluate the different systems.

Epoxy coating with excellent anticorrosion and pH-responsive performances based on DEAEMA modified mesoporous silica nanomaterials

A pH-responsive epoxy composite coating was obtained by adding a benzotriazole-containing with pH-responsive nanocontainer to the epoxy coating. The release experimental results of benzotriazole in benzotriazole-loaded nanocontainer show that the cumulative release of benzotriazole increases with the decrease of pH value of the 3.5 wt% NaCl solution. The cumulative release of benzotriazole from nanocontainer in 60 h with different pH are 50.6%, 63.1%, 76.3% and 80.2% for pH = 6.8, 6.0, 5.5 and 5.0, respectively, indicating that benzotriazole has obvious release behavior under weak acid condition, which ensures that the coating with nanocontainer can show active repair performance in different acidic environments. Moreover, the EIS results show that the epoxy coating with benzotriazole-loaded nanocontainer exhibits excellent anticorrosion and active repair properties, and the more severe the corrosion environment, the stronger the repair ability of the coating.

A Durable PVDF/PFOTES-SiO2 Superhydrophobic Coating on AZ31B Mg Alloy with Enhanced Abrasion Resistance Performance and Anti-Corrosion Properties

A simple and practical spray method is employed to prepare a PVDF/PFOTES-SiO2 superhydrophobic composite coating on the AZ31B Mg alloy substrate. The morphology, composition, and water contact angle (CA) were measured by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM) and contact angle measuring instrument. Hydrophilic nano-SiO2 is modified by PFOTES to obtain hydrophobicity. The influence of the mass of PFOTES-SiO2 to PVDF on the hydrophobic properties was studied. The wear resistance and stability of the composite coating have been investigated by immersion test, cross-cut adhesion test and friction test. Additionally, the corrosion resistance was measured by electrochemical workstation and salt spray corrosion test. The CA of PVDF/PFOTES-SiO2 coating is 161.3° and the sliding angle (SAs) is less than 2°. After 10× the sandpaper friction test, the superhydrophobic contact angle of the coating remained above 155°, and the sliding angle was less than 5°, which indicated that the prepared coating is a strong superhydrophobic coating with good wear resistance. The results of the electrochemical tests show that the superhydrophobic coating improved the anti-corrosion performance of Mg alloy, and the water contact angle is greater than 150° after 168 h salt spray corrosion test. Due to its excellent superhydrophobicity, wear resistance and anti-corrosion properties, the robust PVDF/PFOTES-SiO2 coating is considered to have great potential for future applications in the automotive and marine industries.

Single-Atom Co Doped in Ultrathin WO3 Arrays for the Enhanced Hydrogen Evolution Reaction in a Wide pH Range.

Owing to the scarcity of Pt, low-cost, stable, and efficient nonprecious metal-based electrocatalysts that can be applied in a wide pH range for the hydrogen evolution reaction (HER) are urgently required. Herein, a highly efficient and robust HER catalyst that is applicable at all pH values is fabricated, containing isolated Co-single atomic sites anchored in the self-supported WO3 arrays grown on Cu foam. At a current density of 10 mA cm-2, the HER overpotentials are 117, 105, and 149 mV at pH values of 0, 7, and 14, respectively, which are significantly lower than those of the undoped WO3, suggesting superior electrocatalytic H2-evolution activity at all pH values. The catalyst also exhibits long-term stability over a wide pH range, particularly in an acidic medium over 24 h, owing to the excellent anticorrosion properties of WO3. Density functional theory calculations prove that the enhanced HER activity is attributed to the isolated Co sites because these optimize the adsorption energy of H* species on WO3. Moreover, the high electrical conductivity of Co-doped WO3 and the three-dimensional array structure supported on the porous metal support afford a catalyst with suitable HER kinetics to enhance the catalytic performance.

Underwater superoleophobic composite coating characteristic of durable antifouling and anticorrosion properties in marine environment

Biofouling of marine vessels often results in low fuel efficiency and severe hull corrosion, an ecological friendly coating with long durability and high Benefit-cost is greatly desired to prevent biofouling and bioadhesion. Herein, a facile “Glue + Powder” strategy was employed to synthesize a composite coating with satisfactory oil-repellent and anticorrosion properties, in which the hexadecyl-trimethoxysilane modified SiO 2 nanoparticles (NPs) act as superhydrophobic undercoating and polyacrylic acid modified ZnO NPs implanted in polydimethylsiloxane as superoleophobic finishing coat. Immersion tests evidenced that no obvious cracks appeared on the surface of the bifunctional composite coating, without apparent adhesion loss even after 30 d of immersion in 3.5% NaCl solution. Electrochemical tests demonstrated that the Al alloy electrode lacquered by the composite coating presents a high impedance (above 10 9 Ω cm 2 ) even after 25 d of immersion in 3.5% NaCl solution, dramatically reducing the corrosion rate of Al alloy by 7 orders of magnitude. In addition, tribocorrosion test indicated that the coated Al alloy specimen can survive from 120 cycles of friction-wear under 0.5 MPa loading, exhibiting excellent corrosion and wear resistance. Antifouling test showed that the bifunctional composite coating could reduce the underwater adhesion of oily molecules with an oil contact angle of 160 ± 2°, presenting excellent superoleophobicity and immune of the adhesion of Pseudomonas sp. and following formation of biofilm. Hopefully, it could be one of competitive marine antifouling coatings. • Underwater oil-repellent, waterproof and anticorrosion coating was prepared by “Glue + Powder” strategy. • The composite coating showed excellent antifouling and anticorrosion properties in 3.5% NaCl solution. • The antifouling and anticorrosion is attributed to the superoleophobic surface and superhydrophobic interlayer.

The Effect of Plume Generated on the Microstructural Behavior of the Weld Mixed Zone in High-Speed Laser Dissimilar Welding

Dissimilar laser welding has been researched to combine the excellent anticorrosion and high strength properties of Ti and the low weight and cost of Al. However, when welding dissimilar Al and Ti sheets, many kinds of intermetallic compound are easily generated. Therefore, intermetallic compounds and differences in material properties make joining such dissimilar metals very difficult. Previous studies clarified that ultra-high welding speed could suppress the weld defects. To elucidate the mechanism of Al and Ti dissimilar laser welding, material behavior of the weld fusion zone and components of fume generated during the ultra-high speed welding process were observed and analyzed using energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high speed cameras, and a spectrometer. The results show that the atom movement of Al and Ti in the weld plume affects the behavior of elemental components distributed in the weld fusion zone.

Predicting the formation characteristics of titanium alloy self-locking nuts

Titanium alloy is important for the aerospace industry because of its high specific strength as well as excellent anti-corrosion and anti-oxidative properties. In this paper, a three-dimensional thermo-mechanical coupled simulation was carried out to predict the formation characteristics of a TC4 titanium alloy self-locking nut during the upset forging process. The stability of the upset-forged material was analyzed, and the influences of initial temperature and deformation velocity on the quality of the formed material were investigated. The results show that if the length:diameter ratio of the sample is less than 3.27, the upset-forged material tends to be stable, so we selected a length:diameter ratio of 2.89. Additionally, the properties of the TC4 self-locking nut improved when the initial temperature was increase, and decreased when the velocity of the upper die was increased. Our results provide a theoretical guidance for the formation of TC4 titanium alloy nuts using upset forging.

Simultaneously improved bio-tribological and biological corrosion properties of taC film coated on Ti6Al4V by sealing with ALD

The failure of the implant biomedical materials in the physiological environment mainly depends on the synergistic effect of the corrode and wear. The implant-bone interface is the critical position where the corrosion and wear are often occurred. Most of the work have focused on developing films with anti-corrosion and anti-wear while ignoring the inherent shortcomings in deposition methods. The present paper is therefore focused on investigating the anti-corrosion and bio-tribological performance of the taC composite, in which taC film was firstly fabricated on the Ti6Al4V substrate via hybrid arc ion plating (AIP) system, then a TiO2 layer was deposited on taC surface through atomic layer deposition (ALD). Structural, biological corrosion resistance and bio-tribological properties of the composites were systematically investigated. Results show that the wear resistance of Ti6Al4V is enhanced by the designing taC composite: the friction coefficients of Cr/taC-TiO2 and Ti/taC-TiO2 are decreasing by 6.5 times in relation to the Ti6Al4V substrate; The wear rates of Cr/taC-TiO2 and Ti/taC-TiO2 are 1.7 × 10−6 mm3/Nm and 6.5 × 10−7 mm3/Nm respectively, which are lower than that of Ti6Al4V. Excellent anti-corrosion property was achieved by TiO2 sealed specimen, as evidenced by an order of magnitude higher corrosion potential and notable reduced corrosion current density compared to bare substrate. This is due to the high sealing efficiency of TiO2 layer to reduce the porosity of the taC film when compared with the Cr/taC and Ti/taC film. These composite films on Ti6Al4V substrates, which simultaneously prove an excellent wear resistance and good corrosion resistance, thus could have prospective application in biomedical implants.

Electronic conductive and corrosion mechanisms of dual nanostructure CuCr-doped hydrogenated carbon films for SS316L bipolar plates

The carbon-coated metal bipolar plate is believed to be a potential substitute of the traditional graphite bipolar plate. However, instead of pyrolytic graphite, carbon films grown by using hydrocarbon as the carbon source have a higher deposition rate but lower conductivity. Aiming to resolve this complaint, here, a new strategy of in-situ catalytic decomposition of methane via reactive magnetron sputtering of a Cr0.6Cu0.4 target in methane and argon atmosphere was proposed without heating. A dual structure C18.6Cr0.06Cu (S65) film with graphene-like carbon bridged nano-Cu clusters within amorphous carbon clusters embedded, which has a deposition rate (~24.1 nm/min) about four times higher than other reports (≤6.2 nm/min), with the interface contact resistance of 7.34 mΩ cm2. The distinct mechanisms of good conductive and anti-corrosion can be understood as (1) the bridged nano-Cu clusters and graphene-like carbon structures construct an interconnected network in the bulk S65 film, endowing the S65 good conductivity, (2) the nano-Cu clusters are isolated by the graphene-like carbon structures and amorphous carbon clusters, which protect the nano-Cu clusters un-contacting with the corrosive medium, bringing the S65 excellent anti-corrosion properties. Our work opens a new route for the rapid deposition of carbon film for bipolar plate application.

Insights into the inhibition mechanism of 2,5-bis(4-pyridyl)-1,3,4-oxadiazole for carbon steel corrosion in hydrochloric acid pickling via experimental and computational approaches

The addition of 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (4-POX) as organic corrosion inhibitor of carbon steel (CS) in 1 M HCl solution was assessed exploiting weight loss and electrochemical measurements as well as surface analyses. The gravimetric results showed that the 4-POX presents excellent anticorrosive properties on CS substrate, and its inhibition performance, ƞ(%), augmented with the 4-POX concentration to reach a maximum value of 93.6% at 1 mM afterwards 6 h embedding in 1 M HCl at 303 K. The AC impedance findings revealed that the addition of 4-POX to the corrosive medium leads to a decrease of the charge capacitance resulting in a systematic improve of the interface charge/discharge function and forms an adsorbed layer over the metal surface. Furthermore, SEM, water contact angle and XPS methods supported the development of a protective film over CS substrate surface afterwards addition of 4-POX. DFT calculations and MD simulations of 2,5-bis(n-pyridyl)-1,3,4 oxadiazole (n = 2, 3 and 4) derivatives were exploited to get better insight, about structural and electronic effects in relation to the anticorrosion properties and to envisage the interactions of the investigated inhibitors with metal surface atoms along with corrosive species. The cytotoxicity of 4-POX was also determined using the cell culture system.

Epoxy/alumina composite coating on welded steel 316L with excellent wear and anticorrosion properties

The main purpose of this study is to elaborate anticorrosive coatings for the welded steel 316L, since this later is widely used in industrial field. Hence, within this work we have studied the electrochemical behaviour of different zones of the welded steel 316 in 1 M HCl media. The macrography study of the welded steel has revealed the different areas with a good contrast. We have stated three different zones, namely; melted zone (MZ), heat affected zone (HAZ) and base metal zone (BM). Impedance studies on welded steel 316L were conducted in 1 M HCl solution, coating of Epoxy/Alumina composite was applied on different zones, in order to reveal the anti-corrosion efficiency in each zone. Scanning electron microscopy (SEM) analysis was undertaken in order to check how far the used coating in such aggressive media protects the studied zones and these findings were assessed by water contact angle measurements. The choice of this coating is based on the cost and the safety. We concluded that the Epoxy/Alumina composite has a good protecting effect regarding welded steel in aggressive media.

Study on alkylated Schiff base of a triazole with 3, 5-di-tert-butyl-4-hydroxybenzaldehyde as a novel multifunctional lubricant additive

A novel triazole derived multifunctional lube additive (MFA) denoted as TBB was designed and synthesized for improved metal surface interaction properties and inhibiting lubricant degradation. At first, two hindered phenolic moieties were coupled with the heterocyclic 3,5-diamino-1,2,4-triazole framework by the reaction with 3, 5-di-tert-butyl-4-hydroxybenzaldehyde to give the intermediate Schiff base followed by alkylation through the reaction of bromododecane for better solubility in polyol base oil. After molecular characterization, the TBB performance evaluation for the lubricity and antioxidant characteristics was done following the standard test methods in the polyol. At a low concentration of 1000 ppm, the average wear scar diameter and average friction coefficient was reduced by 16.92% and 64.39% respectively while the RBOT time was increased by 70.76% at 5000 ppm concentration with respect to polol base oil. The standard corrosion testing procedures were used for evaluating the anti-corrosion potential of additive TBB in terms of weight loss, corrosion rate, and penetration rate which were found to be reduced at 5000 ppm concentration to the values as 0.01 ± 0.01 mg, 0.01 ± 0.005 mdd, and 0.001 ± 0.001 mpy from the 0.60 ± 0.04 mg, 0.62 ± 0.03 mdd, and 0.114 ± 0.009 mpy respectively for blank polyol. So TBB showed moderate efficiency as a lubricity improver but showed excellent antioxidant and anti-corrosion additive properties.

Ultralow friction and corrosion resistant polyurethane/silicone oil composite coating reinforced by functionalized graphene oxide

Ultralow friction and corrosion resistant polymer composite coatings were prepared by introducing diverse terminated silicone oils (TSOs) into polyurethane (PU) resin and the graphene oxide (GO) functionalized by aniline oligomer (AOFG) was inducted to improve performances of PU composite coatings. CH3-TSO modified PU coating with the content of 5% had the optimal friction-reduced effect due to the weakest binding force with PU framework. The CH3-TSO/AOFG/PU trinary coating (GMSOPU) showed further-elevated enhanced resistance to high load and speed because that AOFG crosslinked with PU skeleton and achieved the denser and stronger coating structure to withstand the friction stress on the basis of CH3-TSO liquid lubrication. Moreover, CH3-TSO increased the contact angle of the PU composite coatings and effectively inhibited erosion. Combining with the synergistic effect of the CH3-TSO and AOFG, compact GMSOPU coating had the most excellent anti-corrosion properties due to the enhanced permeability resistance and extended corrosion path.

Preparation and characterization of Nd-doped double-layer silane anticorrosion coating on AZ91D magnesium alloy surface

Abstract Magnesium alloys have found widespread application as engineering and functional materials in automobile, aerospace, electronics, and biomedical industries. However, these alloys are susceptible to corrosion, and the development of new anticorrosion coatings on Mg alloys surface is urgently needed. In this work, pristine and doped double-layer silane coatings were applied to the AZ91D Mg alloy surface in order to improve its corrosion resistance properties in a 3.5% NaCl solution. The doped silane coatings consisted of KH-550 as the bottom layer and Nd(NO3)3-doped bis-(γ-triethoxysilylpropyl)-tetrasulfide (BTESPT) as the top layer. The effect of Nd(NO3)3 concentration on the corrosion inhibition properties of silane coatings was studied, and the highest corrosion resistance was achieved when the Nd(NO3)3 concentration was 5 × 10−3 mol/L. Compared to the pristine coating, the doped coating had enhanced hydrophobicity with a water contact angle of 108° and, to the best of our knowledge, one of the lowest corrosion current densities (1.51 × 10−2 μA/cm2) reported to date for treated AZ91D. These significant improvements were attributed to the presence of the Si-O-Nd network in the doped coating, leading to the uniform and homogeneous nature and excellent anticorrosion properties of Nd-doped silane coating.

Electronic Surveillance and Security Applications of Magnetic Microwires

Applications in security and electronic surveillance require a combination of excellent magnetic softness with good mechanical and anticorrosive properties and low dimensionality. We overviewed the feasibility of using glass-coated microwires for electronic article surveillance and security applications, as well as different routes of tuning the magnetic properties of individual microwires or microwire arrays, making them quite attractive for electronic article surveillance and security applications. We provide the routes for tuning the hysteresis loops’ nonlinearity by the magnetostatic interaction between the microwires in the arrays of different types of amorphous microwires. The presence of neighboring microwire (either Fe- or Co-based) significantly affects the hysteresis loop of the whole microwires array. In a microwires array containing magnetically bistable microwires, we observed splitting of the initially rectangular hysteresis loop with a number of Barkhausen jumps correlated with the number of magnetically bistable microwires. Essentially, nonlinear and irregular hysteresis loops have been observed in mixed arrays containing Fe- and Co-rich microwires. The obtained nonlinearity in hysteresis loops allowed to increase the harmonics and tune their magnetic field dependencies. On the other hand, several routes allowing to tune the switching field by either postprocessing or modifying the magnetoelastic anisotropy have been reviewed. Nonlinear hysteresis loops have been also observed upon devitrification of amorphous microwires. Semihard magnetic microwires have been obtained by annealing of Fe–Pt–Si microwires. The observed unique combination of magnetic properties together with thin dimensions and excellent mechanical and anticorrosive properties provide excellent perspectives for the use of glass-coated microwires for security and electronic surveillance applications.

Influence of N2 flow rate on microstructure and properties of CrNx ceramic films prepared by MPP technique at low temperature

In this study, CrNx ceramic films were prepared utilizing modulated pulsed power magnetron sputtering (MPP) technique at low deposition temperature, with varying flow rates of the reactive gas, i.e. N2. The influences of N2 flow rate on the density of the plasma surrounding the target sheath, microstructure evolution, mechanical/tribological and anti-corrosion properties of the as-deposited CrNx ceramic films were investigated systematically. Results indicated that the plasma density increased sharply with increasing N2 flow rate in the range of 75 sccm to 175 sccm. Nevertheless, with further increase of N2 flow rate to 200 sccm, the growing trend of ionization slowed down probably due to the insufficiency of the power density. With increasing N2 flow rate, the Cr elemental concentration decreased from 69.7 at.% to 57.5 at.%, and that of N increased from 23.2 at.% to 36.6 at.%. The sub-stoichiometric ratio of the CrN films could be attributed to the relative lower reactive kinetic energy at low deposition temperature. The analyses on the microstructure evolution of CrNx films revealed that with insufficient introduced nitrogen, competitive growth between Cr2N(110), Cr2N(111), Cr(110) phases (note that all crystalline planes indexed here are parallel to the coating surface) were found; and with relative sufficient nitrogen, fcc-CrN phase took over, with preferred orientation of (111). Due to the improvement of density and the fine-grain strengthening mechanism, with 100 sccm N2 flow rate, the hardness of the CrNx films obtained the maximum value of 21.4 GPa. The films deposited at 75 sccm nitrogen showed the highest friction coefficient (i.e. ~0.75), which could be partially attributed to the presence of impurity particles on the film surface. And for the remaining films, the friction coefficient maintained in the range of 0.38–0.52. As for the anti-corrosion properties, the CrNx film deposited at 100 sccm nitrogen showed the lowest corrosion current (i.e. 44.2 nA/cm2), indicating excellent anti-corrosion property.

Rapid curing and self-stratifying lacquer coating with antifouling and anticorrosive properties

Natural lacquers have long been used as environment-friendly and renewable coatings. Generally, they dry slowly and do not have fouling resistance limiting their applications. Herein, we report a rapid curing, self-stratifying amphiphilic hybrid lacquer coating with excellent antifouling and anticorrosive properties. The coating was prepared by using a natural lacquer coupled with hyperbranched polysiloxane terminated by multi-amine (HPSi) and silane-terminated amphiphilic telomer (S-FP) through a facile sol–gel process. The introduction of HPSi greatly shortened the drying time and improved the mechanical properties of the natural lacquer coating. As HPSi content increased, the drying speed and surface hardness of the coating increased. Particularly, the incorporation of a non-leaching, self-enriched amphiphilic telomer into the hybrid lacquer conferred it an excellent antifouling performance but preserved its anticorrosive and mechanical properties. The flexibility and bacteria-resistant ability of the coating were significantly improved with S-FP content. The study provides a new strategy for modification of natural lacquer, and the hybrid lacquers are expected to be used in development of coatings with both antifouling and anticorrosive performance.