Effective Corrosion Protection Research Articles

Optimization the quantity, locations and output currents of anodes to improve cathodic protection effect of semi-submersible crane vessel

In order to improve corrosion protection effect of semi-submersible crane vessel (SSCV), 3-D boundary element method combined with automatic movement of anodes and adjustment of currents is developed to optimize anode quantity, location and output current of impressed current cathodic protection system for SSCV. Numerical simulation results show that protection potential of SSCV is obviously smoothed after optimization. The protection effect of SSCV in four different states is also predicted and simulation results indicate that SSCV is well protected in the whole service life when the protective coating on hull is repainted every seven years. Finally, challenges associated with cathodic protection providing for marine engineering equipment are discussed.

A Multiple-Action Self-Healing Coating

This paper describes a self-healing coating for corrosion protection of metals which combines two different types of self-healing mechanisms in one coating with multiple-healing functionality. 2-Mercaptobenzothiazole (MBT) was loaded into layered double hydroxide (LDH) carriers which were mixed into an acrylated polycaprolactone polyurethane based shape recovery coating and applied on Hot Dip Galvanized steel (HDG). The effect of triggered release of MBT on the protection of HDG became visible when samples with manually applied defects in the coating were immersed in 0.05 M NaCl solution (first, autonomous healing mechanism). The shape recovery (second, non-autonomous healing mechanism) was triggered by heating the samples for 2 minutes to 60°C. SEM-EDX and Raman Spectroscopy proved the presence of MBT in the LDH, in the MBT-loaded LDH in the coating and the released MBT on the HDG surface in the damaged area after being in contact with a solution containing corrosive ions. Electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET) demonstrate the corrosion protection effect of MBT in the coating with a defect and the restoration of the barrier properties of the coating after defect closure. This way, the independent mechanisms of this multi-action self-healing coating could be demonstrated.

Preparation and characterization of UV-cured epoxy/clay nanocomposite coatings on carbon steel

ABSTRACTPolymer-clay nanocomposites are compounds in which nanoclay particles are distributed in a polymer matrix. Epoxy-clay nanocomposites have become a very interesting topic among researchers in the past two decades because nanoclays have a positive effect on the mechanical, thermal and especially barrier anticorrosive performance of the polymers. In this study, epoxy-montmorillonite organoclay (OMMT) nanocomposite coatings were prepared and deposited on carbon steel substrates. The coatings were prepared through in situ polymerization and by UV-curing technique. The OMMT was added to epoxy resin at loadings between 0 wt.% and 5 wt.%, the particles of OMMT were dispersed using forced agitation-sonication and deposited on carbon steel coupons. The nanocomposite coatings obtained have been characterized by scanning electron microscopy (SEM), spectroscopy Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and evaluated their corrosion protection effect on cold rolled carbon steel coupons by performing visual analysis. The X-ray analysis showed that exfoliation occurred for the OMMT in the polymer matrix, the SEM analysis showed that OMMT was homogenous dispersed in the polymer matrix and the coatings were uniform. The FTIR analysis showed the characteristic bands of epoxy resin and OMMT in the composite. The results showed that 1 wt.% OMMT coating exhibit better anticorrosive properties than pure epoxy.

해수 내 아크 아연 용사코팅 층의 전기화학적 특성

In this paper, arc Zn thermal spray coating was carried out on the SS400 steel, and then various electrochemical characteristics and surface damage behavior of Zn thermal spray coating layer were analyzed. As the results, the potential of Zn thermal spray coating layer presented driving voltage above 300 mV compare to that of SS400 steel. The passivity characteristic in anodic polarization curve was not presented. It was adequate to as sacrificial anode material. In the surface damage after galvanostatic experiments, uniform corrosion tendency of Zn thermal spray coating layer was clearly observed with acceleration of the dissolution reaction. In conclusion, Zn thermal spray coating could be determined to represent the corrosion protection effect by stable sacrificial anodic cathodic protection method in seawater because it had sufficient driving voltage and uniform corrosion damage tendency for the SS400 steel.

316L stainless steel coatings on ZE41 magnesium alloy using HVOF thermal spray for corrosion protection

Abstract Stainless steel coatings have been applied on the surface of ZE41 magnesium alloy using High Velocity Oxygen-Fuel as deposition technique to improve the corrosion performance. Some parameters of the thermal spraying process have been studied (spraying distance, number of layers and gun speed) to produce homogeneous and protective coatings without deteriorating the low melting temperature substrate. Homogeneous, crack-free, fully dense coatings with thicknesses in the range of 42–478 μm were obtained. Electrochemical corrosion tests were used to test the corrosion protection effectiveness of the different coatings. Two of the sprayed stainless steel coatings were capable of protecting the magnesium substrate for 7 days in contact with 3.5 wt.% NaCl aqueous solution, with corrosion resistances close to bulk stainless steel. After 48 days of immersion, one coating was still an effective corrosion barrier for the magnesium substrate, without any sign of substrate degradation. A corrosion mechanism for each tested specimen has been proposed.

Electrochemical synthesis of polymer based on 4-(2-thienyl)benzenamine in aqueous solutions: Electrochemical properties, characterization and application

4-(2-Thienyl)benzenamine (TBA) was successfully synthesized by a simple method including substitution of thiophene on p-nitroaniline followed by reduction of nitro group. Structure of the synthesized monomer was verified using IR, 1H NMR, GC–MS and elemental analysis techniques. Corresponding poly 4-(2-thienyl)benzenamine) (PTBA) was electrochemically synthesized in acidic aqueous solution by cyclic potential sweep method for the first time. Characterization of the resulting polymer was performed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), UV–vis and IR spectroscopies, and scanning electron microscopy (SEM). Effects of pH and temperature on the electroactivity of the polymer modified electrode were investigated. The corrosion behavior of PTBA in 3.5wt% NaCl solution was studied by potentiodynamic polarization test and electrochemical impedance spectroscopy. The PTBA was found to exhibit enhanced corrosion protection effect on stainless steel electrode in comparison with polyaniline (PANI) and polythiophene (PTh) homopolymers.

The adhesion of corrosion protection coating systems for offshore wind power constructions after three years under offshore exposure

Corrosion protection coating systems for offshore wind power constructions were subjected to offshore conditions on a test site in the North Sea. The systems included organic coatings and duplex (spray metal and organic system) coatings. Special exposure specimens were designed and manufactured and exposed to an offshore environment for three years in order to evaluate their protection performance. The adhesion in terms of pull-off strength and fracture mode was measured on coatings in the underwater zone and in the intermediate zone. All samples met the requirements for offshore ageing in terms of adhesion. An adhesion-based “corrosion protection effect” (CE) is introduced and calculated for the coating systems.

Comparison of the synergistic effects of inhibitor mixtures tailored for enhanced corrosion protection of bare and coated AA2024-T3

Abstract The replacement of chromate-based corrosion inhibitors is a requirement for the aerospace sector. New developments demand additional studies to find synergistic combinations of inhibiting species. This paper discusses the synergistic effect resulting from various corrosion inhibitor mixtures proposed for the corrosion protection of aluminum alloy 2024-T3. The corrosion inhibition efficiency and the synergistic factors were determined for AA2024-T3 coupons immersed in 0.05 M NaCl solutions, containing either a single inhibitor or binary combinations of inhibitors. The following inhibitors were tested: Ce 3 + , 8-hydroxyquinoline (8HQ), salicylaldoxime (SAL), and 2,5-dimercapto-1,3,4-thiadiazolate (DMTD). Electrochemical impedance spectroscopy (EIS) and ATR-FTIR in Kretschmann geometry were used to evaluate the chemical and electrochemical variations during the exposure of bare coupons to inhibitor-containing NaCl solutions. The results allowed calculating the synergistic effect for binary mixtures and the most effective mixtures were those containing 8HQ-SAL and DMTD-8HQ. The synergistic effect was also determined for coated coupons. A water-based epoxy coating was modified with calcium carbonate microparticles, loaded beforehand with single inhibitors or with binary mixtures. EIS measurements were performed in 0.5 M NaCl and the results revealed that the epoxy coatings modified with CaCO 3 microparticles, loaded with inhibitor mixtures, provided enhanced corrosion protection. The most effective corrosion protection was observed for two mixtures: CaCO 3 (8HQ + SAL) and CaCO 3 (Ce + SAL). Interestingly, the results revealed that the synergistic effect on bare AA2024-T3 can be different from the situation where the same inhibitor mixtures are used in smart, anti-corrosive coatings.

Self-healing effect of ceria electrodeposited thin films on stainless steel in aggressive 0.5 mol/L NaCl aqueous solution

The self-healing effect of electrochemically deposited CeO2-Ce2O3 films on stainless steel OC404 (SS) in 0.5 mol/L NaCl solution was studied. It was established that the corrosion potential of the steel, after covering it with CeO2-Ce2O3 layer and thermal treatment (i.e. potential of the system CeO2-Ce2O3/SSt.t.), was shifted sharply to a considerably more positive value, while the corrosion current was reduced noticeably. The X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) analyses on the observed scratched surface area of the system CeO2-Ce2O3/SSt.t., after exposure of investigated specimens to 0.5 mol/L NaCl corrosion media, showed partial accumulation of ceria, as well as remarkable increase in the concentrations of oxides of Al, Cr and Fe, on the mechanically revealed steel surface. On the basis of the obtained results one could conclude that the secondary passive oxide/hydroxide films, formed after a definite time interval of exposure to corrosion media, acted as barriers, hindering the corrosion processes in active zones. A hypothesis was put forward about the mechanism of self-repairing oxide layers on the steel surface and their corrosion protection effect respectively.

Cathodic Protection Effect of Reinforced Concrete Beam Specimens with Zinc Sacrificial Anode in Marine Environment

This study is to acquire the confirmation data regarding the cathodic protection characteristics for reinforced concrete beam specimens with zinc sacrificial anode in 15% salt water. It was possible to confirm the performance of sacrificial anode cathodic protection system by the measurement of potentials and concrete resistivity for the reinforced concrete beam specimens applied with zinc sacrificial anode in mortar topside of the concrete specimens. The corrosion potential and cathodic protection potential were measured by potentiostat, and 4 hour depolarization potentials were measured after disconnecting with anode for 4 hours. It was confirmed that the cathodic protection for reinforced concrete structures by means of zinc sacrificial anode were very effective corrosion protection technology in marine environments.

Electrochemical and DFT studies of quinoline derivatives on corrosion inhibition of AA5052 aluminium alloy in NaCl solution

Two quinoline derivatives, 8-aminoquinoline (8-AQ) and 8-nitroquinoline (8-NQ), have been used as inhibitors to examine their corrosion protection effect on AA5052 aluminium alloy in 3% NaCl solution. The weight-loss and electrochemical measurement have indicated that 8-AQ and 8-NQ play as anodic inhibitor to retard the anodic electrochemical process. SEM/EDS analysis clearly shows that 8-AQ and 8-NQ form a protective film on the AA5052 alloy surface. Density functional theory (DFT) calculation confirmed the formation of strong hybridization between the p-orbital of reactive sites in the inhibitor molecules and the sp-orbital of the Al atom. 8-aminoquinoline and 8-nitroquinoline may be useful as effective corrosion inhibitors for aluminium alloys.

Dual-Function Smart Electrolyte for Dye-Sensitized Solar Cells: 5-Mercaptotetrazoles as Redox Mediator and Corrosion Repressor

Metal charge collectors are an essential component of photovoltaic modules, facilitating charge collection over larger areas. Their application in dye-sensitized solar cells has so far been hampered by two major factors: (1) the redox mediators employed in these photoelectrochemical devices are generally corrosive to metals, and (2) they generally show low overpotentials for their redox reactions on these metal surfaces, which leads to significant recombination losses at the photoanode. Here, a thiolate-based redox mediator, sodium 1-phenyl-1H-5-mercaptotetrazole (Tph), is shown to form self-assembled monolayers on silver electrodes and to act as an effective corrosion protection layer while also exhibiting high overpotentials on these metals at the photoanode. The anticorrosive properties are strongly dependent on the structure of the thiolate. Replacement of the phenyl group in Tph with a methyl substituent accelerates the corrosion process by orders of magnitude. Finally, we demonstrate the applicability of Tph-based electrolytes in a 60 cm2 dye-sensitized solar cell comprising unprotected silver charge-collecting electrodes.

Electrochemical synthesis of polymer based on 4-(2-furyl) benzenamine: Electrochemical properties, characterization and applications

Abstract 4-(2-Furyl) benzenamine (FBA), was successfully synthesized by a simple method including substitution of furan on p-nitroaniline followed by reduction of nitro group. Structure of the synthesized monomer was verified using IR, 1H NMR and GC–MS techniques. Corresponding poly(4-(2-furyl) benzenamine) (PFBA) was electrochemically synthesized in acidic aqueous and organic solutions by cyclic potential sweep method. Characterization of the resulting polymer was performed by cyclic voltammetry (CV), IR, UV–vis spectroscopy, and scanning electron microscopy (SEM). Effect of solvent on the electroactivity of the polymer modified electrode was investigated. The HOMO, LUMO levels and band gap energies of the doped and undoped form of the PFBA were calculated using UV–vis and CV data. The electrochromic properties and corrosion behavior of PFBA were studied. The electrochromic properties of the copolymer film, electrochemically coated on transparent conductive oxide, corroborate multi-color electrochromic behavior of the polymer whenever the applied potential was switched from reducing (yellow) to oxidizing status (green). The FBA polymer was found to exhibit enhanced corrosion protection effect on steel electrode in comparison with corresponding polyaniline (PANI) and polyfuran (PFu) homopolymers based on series of electrochemical measurements in 3.5 wt% NaCl electrolyte solutions.

Investigation of composition and structure for a novel Ti–Zr chemical conversion coating on 6063 aluminum alloy

Abstract A novel chemical conversion coating was prepared by adding tannic acid and coating-forming accelerator in the treatment solution containing titanium and zirconium ions. Corrosion behavior of the coatings in contact with 3.5% NaCl solution was investigated using potentiodynamic measurement. The structure and composition of the coatings were determined with EDS, XPS and IR. The morphologies of the coatings were observed with scanning electron microscopy (SEM). According to the results, the modified Ti–Zr based conversion coating (MTZ) shows a smoother and more compact morphology characterization comparing with the traditional Ti–Zr treated (TZ) substrates; The Tafel results and the long-time immersion experiments also indicate that the MTZ coating presents a more effective corrosion protection property compared with the TZ coating; The MTZ coating is a multi-components chemical conversion coating which is mainly composed of metal oxide (TiO 2 , ZrO 2 , V 2 O 5 , Al 2 O 3 ), fluoride (AlF 3 and ZrF 4 ) and metal–organic complex.

Nghiên cứu ảnh hưởng của một số phụ gia bê tông đến ăn mòn cốt thép trong môi trường nước biển Tiếp theo Nghiên cứu chuyển hóa zerumbone oxit với một số axit hydrazid thơm Trả lời

In the study natural tests of reinforced concrete samples contained corrosion inhibitors including sodium silicate, urea, thiourea (in the concentrations: 0, 0.05, 0.10, 0.15 and 0.20%) and silica fume (in the volume of 0; 2.5, 5.0, 7.5 and 10%) in the Vietnam tropical sea have been carried out and the effects of depth and their nature and concentration on the corrosion behavior of Pomina and Vina carbon steels embedded in concrete after 01 month of testing were investigated. It is found that the corrosion protection effectiveness (η) of the four inhibitors are η (Thiourea) > η (Urea) > η (Sodium silicate) > η (Silica fume). The steel-reinforced corrosion activity of the sea at the depth of 0.5 m was higher than that at the depth of 1m.

Corrosion protective poly(aniline-co-o-anisidine) coatings on mild steel

Syntheses of corrosion protective poly(aniline-co-o-anisidine) (PAOA) coatings were carried out on mild steel by the electrochemical copolymerization of aniline with o-anisidine under cyclic voltammetry conditions. An aqueous salicylate solution was used as the supporting electrolyte for the synthesis of PAOA coatings on mild steel. These coatings were characterized with cyclic voltammetry, ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and scanning electron microscopy. The FTIR and 1H-NMR spectroscopy studies reveal that during copolymerization of aniline and o-anisidine, there are more o-anisidine units than aniline units in PAOA copolymer. The corrosion protection offered by PAOA coatings to mild steel was investigated in aqueous 3% NaCl solutions using the potentiodynamic polarization technique. The results of the potentiodynamic polarization measurements showed that the PAOA coatings provided more effective corrosion protection to mild steel than the respective homopolymers. The corrosion rate was observed to be dependent on the feed ratio of o-anisidine used for synthesis of the copolymer coatings.

Thermal Spraying Arc Process with Two Dissimilar Wires – Quality Tests

This work presents a part of research for thermal spraying arc process with two wires with different chemical composition, aluminium and zinc, whose coating is capable of providing effective long term corrosion protection to steel in a wide range of land and marine environment. It covers quality tests: optical and microscopic characterization of deposits, local micro-composition determined by secondary and backscatter electron, images obtained on sections of the areas investigated in the form of quantitative and qualitative estimates micro-composite. Diffractometer and spectral analysis of the coatings complete the metallographic characterization. The theme can be studied by pupils in technological high schools and get introduced to modern investigative techniques and different quality tests.

The Effects of Inappropriate Corrosion Protection

The effectiveness of corrosion protection depends on several complex processes connected with the development of the construction, such as:

The Corrosion Processes Effect on Surface Roughness of Bonded Magnetic Material Based on Nd-(Fe,Co)-B Powder Type

This paper presents an analysis of the Nd-(Fe,Co)-B bonded magnetic materials surface before and after corrosion tests. In the technological process of bonded magnetic materials the main difficulty is the fact that in the presence of small amounts of oxygen magnetic powders (having in their composition a highly active, a rare earth element) the particle surface easily cover with an oxide layer. The oxides phases are creating and furthermore the presence of this kind of paramagnetic phase on the powder particles surface adversely affects on the properties of the final product. Important is to protect the surface against spontaneously oxidation of the magnetic materials. One of the activities way to surface isolation is creating the additional protection coating (biencapsulation). Biencapsulation is a protection process in which not only set resin layer, but also an additional protective coating has been applied. The powder particles are coated with protective coatings: Ni-P/epoxy resin and phosphate/epoxy resin. In the paper the roughness measurement (2D) with profilometer (Taylor Hobson) results were presented. Also the effect of corrosion process evaluation on the bonded magnets surface roughness were determined (sulfate solution pH = 3, the exposure time 4h). It has been found that the application of powder particles biencapsulation with phosphate/epoxy resin coating (in comparison with Ni-P/epoxy resin biencapsulation) leads to a more effective corrosion protection of the final bonded magnets.

Enhancement of corrosion protection effect in poly(2,3-dimethylaniline) via the formation of nanofiber materials by introducing p-phenylenediamine

Abstract Poly(2,3-dimethylaniline) (P(2,3-DMA)) nanofiber was prepared by introducing p-phenylenediamine as an initiator into the reaction mixture solution. The P(2,3-DMA) nanofiber was characterized by X-ray diffraction, Fourier transformation infrared spectroscopy and scanning electron microscopy. The results showed that the introduction of p-phenylenediamine favors one-dimensional growth of P(2,3-DMA). In order to compare the anticorrosion performance of P(2,3-DMA) nanofiber with that of poly(2,3-dimethylaniline) prepared without adding p-phenylenediamine (C-P(2,3-DMA)), epoxy resin coating containing P(2,3-DMA) nanofiber and C-P(2,3-DMA) was painted on mild steel, respectively. The anticorrosion property of the as-prepared nanofiber coating was evaluated by open circuit potential, tafel polarization curves and impedance spectroscopy in 3.5 wt% NaCl aqueous solution. Experimental results indicated that P(2,3-DMA) nanofiber had higher anticorrosion property compared with C-P(2,3-DMA). Hence, the morphology could be responsible for better anti-corrosion performances.