Excellent Anti-corrosion Properties Research Articles

Lignin composite ionic liquid lubricating material as a water-based lubricating fluid additive with excellent lubricating, anti-wear and anti-corrosion properties

A new type of ionic liquid was synthesized from lignin, tetrabutylphosphorus hydroxide, and benzotriazole, and its potential utility as a water-based lubricating additive was studied by comparing the performance of water containing the lubricating additive with that of water. The additive not only decreases the friction and wear of water on steel but also decreases the corrosive effect of water on steel, and improves the utilization rate of lignin, which is difficult to use. The mechanistic analysis of the lubrication in the presence of the ionic liquid revealed that a protective film containing nitrogen is formed on the surface of the steel/steel friction pair, which blocks direct contact of the friction pair and thus induces excellent tribological properties.

Biocomposite coating of Wrightia tinctoria root bark fiber reinforced samarium substituted hydroxyapatite/ polypyrrole on titanium for potential orthopedic applications

The present work is focused on the fabrication of Bellamya javanica rice fields snail shells derived samarium (Sm) substituted hydroxyapatite (Sm-HAP)/polypyrrole (PPy)/Wrightia tinctoria fiber (WTF) biocomposite on titanium (Ti) by electrophoretic deposition for orthopedic applications. The functional groups, phase composition, morphology, elemental composition was examined by various characterization techniques. In addition, the adhesion strength and hardness of the biocomposite coatings was evaluated by mechanical characterization. The corrosion behavior of the as developed biocomposite coating on Ti was determined by potentiodynamic polarization study. Similarly, the antimicrobial activity of the biocomposite was evaluated against two bacterial strains and one fungal strain by well diffusion test. The in vitro bioactivity and biocompatibility of the composite was evaluated for the biocomposite coated Ti. Also, the swelling and degradation behavior of the as fabricated coating were examined in simulated body fluid medium. Hence, from the obtained results it can be concluded that the Sm-HAP/PPy/WTF biocomposite coated Ti exhibited excellent anticorrosion, anti-microbial and biocompatible properties which make them a potential material for high-performance bone implants in the field of orthopedic applications.

Cobalt-phosphorous coatings with tunable composition fabricated by additive-controlled electrodeposition from choline chloride-ethylene glycol deep eutectic solvent for anti-corrosion application

Cobalt-phosphorous (CoP) coatings are promising alternatives for hard chromium due to their outstanding corrosion protection. An excellent CoP coating can efficiently reduce the effects of a corrosive environment. Herein, CoP coatings with a tunable P content, ranging from 5.1 at.% to 20 at.%, are fabricated via a simple electrochemical deposition approach from choline chloride-ethylene glycol (Ethaline)-based deep eutectic solvent (DES) with saccharin (SA) as an additive. The rational introduction of SA induced the formation of close-growing CoP coatings rich in P on the substrate with reduced grain size and surface roughness. It turned out that the crystal structure of the deposited CoP coatings changed from a crystallized state to an amorphous state upon the addition of SA, which accelerated the nucleation rate of the nanocrystals and modified the nucleation model from progressive to instantaneous. The optimal CoP coating prepared exhibited excellent anti-corrosion and barrier protection properties for mild steel in corrosive NaCl solution, functioning up to 10 times better than its counterparts. Our work reveals the central role of additives in tailoring the structure and composition of the deposited CoP coatings in Ethaline-based DES and offers a new avenue for fabricating high-performance coating materials for anti-corrosion applications.

Facile preparations of superhydrophobic coatings with self-cleaning, mechanical durability, anticorrosion and easy-repairable properties

A facile and scalable way was developed to successfully prepare multifunctional superhydrophobic coatings (SHCs) by a one-step spraying method. The SHCs could be quickly coated on various substrates on a large scale and cured at room temperature. The as-prepared SHCs exhibited outstanding self-cleaning ability and chemical stability, and special optical properties underwater such as the silver-mirror and black-hole effects. Moreover, the SHCs had excellent anticorrosion property with a protection efficiency of 98.7% for the bare 2a12 Al alloys. Furthermore, the SHCs exhibited excellent mechanical durability and good adhesion strength to the substrate after mechanical abrasion test against 1000 grit SiC sandpaper for 1.0 m at the applied pressure of 5 kPa and scratch test. Additionally, the superhydrophobicity of SHCs could be regenerated by a simple spraying repair process after some severe abrasions, indicating a strong easy-repairable property. The present study therefore suggests that such versatile SHCs are promising for various practical applications in different fields.

A facile method to prepare mesoporous polyaniline hollow nanosphere and its application in self-healing coating

In this work, a facile method was developed to prepare mesoporous polyaniline (mPANI) hollow nanospheres using core/shell structured silica nanospheres as substrates. The prepared mPANI hollow nanospheres were composed of external mesoporous PANI shell and internal mesoporous resorcinol-formaldehyde (RF) resin shell. The average diameter, shell thickness, specific area, average pore diameter, and total pore volume of mPANI hollow nanospheres were 330 nm, 78 nm, 75 m2 g−1, 6.9 nm, and 0.89 cm3 g−1, respectively. 1H-benzotriazole (BTAH) loading rate in mPANI hollow nanospheres was up to 35%. In addition, BTAH can be released from mPANI hollow nanospheres continuously to provide a sustained protection for epoxy coating. Epoxy coating pigmented with 2 wt% mPANI hollow nanospheres loaded with BTAH (mPANI@BTAH) presents remarkable anticorrosion property, and its coating resistance still can be maintained at 109 Ω cm2 even after 60-day immersion in 3.5 wt% NaCl solution. Furthermore, there are only slight rusts at the scratch after 30-day salt spray test, and the coating adhesion force reduced a little, still up to 6.4 MPa, indicating excellent anticorrosion property. Meanwhile, scanning vibrating electrode technique (SVET) results confirmed that epoxy coating pigmented with mPANI@BTAH hollow nanospheres exhibited obvious self-healing function. It can be concluded from the series tests that mPANI@BTAH hollow nanospheres as high performance anticorrosion pigments can strongly improve the anticorrosion performance of epoxy coating through combining the passivating function of polyaniline and corrosion inhibition of BTAH together.

Rapid separation of High-viscosity phosphorous Acid/Tributyl phosphate extraction system by a stable anticorrosive Super-PA-phobic mesh

Inefficient, slow separation resulting from the high viscosity of phosphoric acid (PA) is a crucial problem that limits the process economy of industrial PA extraction. In this work, a super-PA-phobic stainless-steel mesh (SPPSSM) with excellent anticorrosion properties and stability is prepared and used for rapid separation in various PA/tributyl phosphate (TBP) extraction systems. The separation efficiency in batch operation of a PA-enriched raffinate (PER) and TBP-enriched phase (TEP) mixture formed from pure PA and TBP exceeds 97.59%, and the maximum TEP flux is 19.2593 L·m−2·h−1 at 60 °C. The maximum TEP flux of 886.1571 L·m−2·h−1 is obtained for a 20 wt% TBP kerosene solution and 20 wt% PA aqueous solution. A continuous separation device using the SPPSSM as the core component maintains a recovery rate of more than 95.57% in long-term operation, confirming its performance stability and robustness. The stable selective penetration of the SPPSSM originates from its super-PA-phobicity, which results from its rough surface with low surface energy; the SPPSSM repels PA but allows TBP to pass through. The separation ability of the SPPSSM is determined by the viscosity, density, and surface tension of the two liquid phases after extraction. It can be predicted using an equation based on the filtration mode after correction by a coefficient representing the Reynolds and Weber numbers. This work proposes a material for the rapid separation of PA/TBP in extraction systems and broadens the application field of superwetted materials under harsh conditions.

Insight into macroscale superlubricity of polyol aqueous solution induced by protic ionic liquid

Currently, macroscale liquid superlubricity remains limited to low applied loads and typical ceramic friction pairs. In this study, a robust macroscale superlubricity with a coefficient of friction (COF) of approximately 0.006 is realized at the bearing steel interface induced by protic ionic liquids (ILs) in propylene glycol aqueous solution, and the lubrication system exhibits excellent anti-corrosion properties. Results show that superlubricity can be achieved by employing ILs with longer alkyl chains over a wide load (< 350 N) and speed (> 700 r/min) range. By systematically investigating factors affecting superlubricity, including the IL structure, ionization degree, test conditions, polyol, water-to-alcohol ratio, and lubrication state, the superlubricity mechanism is discussed. Notably, a thicker and denser stern layer can be formed using ILs with longer alkyl chains, which participates in the tribochemical reaction with the metal substrate to form a tribofilm during rubbing. The hydrogen bond network layer formed by the hydrogen ion and polycol aqueous solution can withstand high applied loads. Water can be used to reduce the shear stress of polyols, and enable superlubricity to be achieved under high-speed rotations. Moreover, an inevitable running-in period serves as a dispersing contact stress and dynamically forms a lubricating film, where the lubrication state locates mixed lubrication and then transforms into boundary lubrication as the roughness of the contact surface increases. This study is expected to significantly promote the development and application of superlubricity in the engineering field.

Inhibition of Hydrogen Evolution by a Bifunctional Membrane between Anode and Electrolyte of Aluminum-Air Battery.

The hydrogen evolution reaction of the anode is a severe barrier that limits the further commercial application of Al–air batteries. Therefore, this study introduces a bifunctional membrane for the inhibition of hydrogen evolution in Al–air batteries. The reference to Al2O3@PAN as “bifunctional” means that it has both hydrophobic and anti-corrosion functions. Al2O3 can effectively inhibit the migration of hydroxide ions, and PAN is an excellent hydrophobic material. The bifunctional membrane is placed between the aluminum anode and the electrolyte, which can prevent the invasion of excess water and hydroxide ions, thereby inhibiting the hydrogen evolution corrosion of the anode. Electrochemical tests have confirmed that the corrosion inhibition rate of a bifunctional membrane containing 1.82 wt. % Al2O3@PAN is as high as 89.24%. The specific capacity of Al–air batteries containing this membrane can reach 1950 mAh/g, and the utilization rate of the aluminum anode has reached 61.2%, which is helpful in reducing the waste of aluminum resources. The results prove that the bifunctional membrane has excellent anti-corrosion properties. Bifunctional membranes can also be used to prevent the corrosion of metals in other fields.

Research on Microstructures and Properties of High-Strength Anticorrosion Twinning-Induced Plasticity Steels

The microstructures, mechanical properties, and anticorrosion properties of Fe–25Mn–Cr(12, 18 wt.%)–CN TWIP steels compared with nominal Fe–22Mn–0.6C TWIP steel (TWIP-ref) in the solid-solution state were investigated in the present study by using X-ray diffraction (XRD), electron backscattered diffraction (EBSD), transmission electron microscopy (TEM), tensile tests, and potentiodynamic polarization measurement, etc. The results show that the Fe–Mn–Cr–CN TWIP steels have excellent mechanical properties and anticorrosion properties compared to the TWIP-ref steel. The strain-hardening rate of the 12CrN steel is lower than that of the TWIP-ref steel because of the relatively late generation of high-density deformation twins, which resulted in less tensile strength increments during the tensile test. Moreover, M23C6 precipitates enriched with Mn and Fe formed in the Fe–Mn–Cr–CN steel as the Cr content increased, which had an important influence on the mechanical properties and anticorrosion properties. In the Fe–Mn–Cr–CN TWIP steels, because of the influence of the M23C6 precipitation in the 18CrN sample, the yield strength (σYS) is increased slightly, while the ultimate tensile strength (σUTS) and elongation to failure are decreased. In addition, 18CrN has poor corrosion resistance because of the formation of M23C6 precipitation (i.e., it has relatively negative corrosion potential (Ecorr) and a smaller corrosion current density (Icorr)).

A high strength, anti-corrosion and sustainable separator for aqueous zinc-based battery by natural bamboo cellulose

Although aqueous zinc-based batteries (AZBs) have aroused extensive research, there are little studies to develop a separator specifically for AZBs, and the widely used Glass Fiber (GF) has poor mechanical strength, which is difficult to meet the requirements of AZBs. Here, a bamboo cellulose membrane (BCM) with natural nano-scale pores is developed by cellulose nanosheets self-assembled, which can be used as a special separator for AZBs. The hierarchical structure formed by cellulose nanosheets endows BCM with a tensile strength up to 81 MPa, 150 times that of GF, able to well block the penetration of zinc dendrites. The rich natural nano-scale pores in BCM can help to facilitate the homogeneous Zn2+ flux at the surface of zinc anode to achieve uniform deposition. Moreover, BCM shows excellent anti-corrosion properties in a wide pH (3.6–13.6) range. The zinc symmetric cell equipped with BCM exhibits much prolonged cycle life, e.g. up to 5000 h and 5000 h (0.5 mA cm−2 0.5 h) in 3 M Zn(CF3SO3)2 electrolyte and 1 M KOH electrolyte, in contrast to 30 h and 4 h for the cell with conventional GF separator. This work demonstrates that developing special separator is very important for the construction of high-performance AZBs.

Fabrication and properties of micro-additive manufactured Ni-based composite coatings by short-pulsed laser

Laser micro-additive technology exhibits excellent promising applications in processing microelectronic components, fabricating medical implants and improving local properties of micro-devices. In this paper, laser micro-additive technology is utilized to fabricate Ni-based micro-cladding coatings by a short-pulsed laser with the pulse width of 10 ns and maximum power of 20 W, and the effect of laser process parameters on micro-cladding coatings is investigated. Results exhibit that the surface quality of micro-cladding coatings is seriously influenced by the process parameters, and the optimal laser process parameters: power of 16 W, scanning speed of 20 mm/s, transverse overlap ratio of 0.8 and frequency of 20 kHz (laser energy density of 160 J/mm3) are obtained. Subsequently, the immersion tests are carried out for evaluating the oxidation and corrosion properties of Ni-based coatings, and the coatings with the thickness of 10–15 μm exhibit excellent anti-oxidation and anti-corrosion properties compared to substrate due to the shielding effect of micro-cladding coatings. In oxidation region, Fe3O4 and Fe2O3 oxidation layers are formed on substrate accompanied by large amounts of β-FeOOH, γ-FeOOH and α-FeOOH; however, less oxidation reaction occurs on coating surface. In corrosion region, the substrate is covered by granular structures with more β-FeOOH, γ-FeOOH and a few α-FeOOH, and the coating surface is quite smooth with few defects of exfoliation.

Zinc coating on steel by atmosphere plasma spray and their anti-corrosion behavior

In this paper, we report a simple process for Zn coatings based on atmosphere plasma spray (APS) techniques. The Zn coating, prepared at the optimal spraying current of 120A, shows excellent structure characteristics with low porosity and high adhesion strength of 10.42 MPa. After 3000 h of NaCl solution immersion test, no obvious corrosion damage occurred on the surface. The corrosion evolution of Zn-coated steel was mainly transformed from spontaneous passivation of the oxide film to pitting damage by corrosion medium. However, due to the isolation effect and lower self-corrosion potential, the Zn coating could protect steel from corrosion damages, which demonstrates the excellent anti-corrosion property.

Structural and physico-chemical properties of electroactive polyamide/multi-walled carbon nanotubes nanocomposites

Electroactive Polyamide (EPA)/Multi-walled carbon nanotube (MWCNT) nanocomposites (NCs) have been synthesized by in-situ oxidative coupling polymerization of EPA in the presence of MWCNT using ammonium persulphate as an oxidant. Initially, the structural and physical properties were confirmed by X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy, Field emission scanning electron microscope, Transmission electron microscopy, Surface roughness, Water contact angle and Water absorption method. The average roughness value and hydrophobicity and diffusion coefficient of EPA/MWCNT NCs were increased and decreased with addition of MWCNT respectively. The performance of EPA and EPA/MWCNT NCs as protective coating against corrosion of 201 stainless steel was analyzed using electrochemical impedance spectroscopy and potentiodynamic polarization technique. The result shows excellent anticorrosion properties.

CeO2 grafted polydopamine-wrapped graphene to enhance corrosion resistance of coated steel

CeO2 grafted polydopamine-wrapped graphene (G@PDA-CeO2) was prepared by the layer-by-layer assembly to enhance the anticorrosive property of the epoxy resin. Electrochemical measurement results show that embedding 0.5 wt% of G@PDA-CeO2 in the epoxy resin can effectively protect metal substrates for up to 56 days. After being immersed in a 3.5% NaCl solution for 56 days, its impedance modulus at 0.01 Hz is still as high as 1.360 × 108 Ω cm2, which is 2 orders of magnitude higher than pure epoxy resin coating. In addition, the scratch immersion test results show that the composite coating embedded with 0.5 wt% G@PDA-CeO2 has excellent corrosion inhibition. Such excellent anticorrosive property is attributed to the synergistic effect of graphene's outstanding barrier effect, polydopamine's improved dispersibility, and CeO2's efficient corrosion inhibitory effect and weak hydrophilicity. This research provides a promising strategy for the preparation of long-term corrosion-resistant graphene-based polymer anticorrosive coatings.

Effect of Cerium and Magnesium on Surface Microcracks of Al–20Si Alloys Induced by High-Current Pulsed Electron Beam

The effect of Ce and Mg on surface microcracks of Al–20Si alloys induced via high-current pulsed electron beam (HCPEB) was studied. Mg was revealed to refine the primary Si phase in the pristine microstructure by forming a Mg2Si phase, leading to the suppression of microcrack propagation within the brittle phase after HCPEB irradiation. The incorporation of Ce into the Al–Si–Mg alloys further refined the primary Si phase and reduced the local stress concentration in the brittle phase induced by HCPEB irradiation. Ultimately, the surface microcracks were observed to be eliminated by the synergistic effects between the two elements. For Al–20Si–5Mg–0.7Ce alloys, Ce demonstrated a homogeneous distribution in the Al matrix on the HCPEB-irradiated alloy surface, while the Mg and Si exhibited a certain degree of aggregation in the Mg2Si phase. Metastable structures were formed on the HCPEB-irradiated alloy surface, including the nano-primary silicon phase, nano-cellular aluminium structure, and nano-Mg2Si phase. Compared with alloy specimens containing Mg, the Al–20Si–5Mg–0.7Ce alloy specimens exhibited an excellent anticorrosion property after HCPEB irradiation mainly due to the combined effects of the grain refinement and microcrack elimination.

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.