Anti-corrosion Layer Research Articles

Anti-corrosion layer prepared by plasma electrolytic carbonitriding on pure aluminum

In this paper, plasma electrolytic carbonitriding (PEC/N) method was applied to pure aluminum for the first time. The spectroscopic characterization of plasma discharge during PEC/N process was analyzed and the electron temperature was calculated in terms of optical emission spectroscopy. The results showed the discharge plasma was in local thermal equilibrium (LTE) state. Electron concentration and electron temperature were about 6×1021m−3 and 4000K, respectively. The carbonitrided layer contained Al4C3, AlN and Al7C3N3 phases. After PEC/N treatment, the corrosion resistance of pure aluminum was significantly improved, which was related to the formation of nitride phases. This work expands the application of plasma electrolysis technology on the surface modification of low melting point metal.

Some aspects of sherardizing implementation during anticorrosion protection of heat-treated metal parts

The article reveals the peculiarities of obtaining Zn anticorrosive diffusion layers on heat-treated metal parts using sherardizing method. It is shown that sherardizing processes can be successfully used as a final heat treatment operation for some metal parts after hardening in a temperature gap between 350-700 °C. 380-450 °C are the most efficient temperatures of sherardizing process to reveal hardening stresses in details. At the same time, applying sherardizing method for anticorrosive protection of details subjected to final heat treatment may cause a weakening of metal accomplished by a reduction of working properties. This fact can be described by structural changes in metal caused by additional heat impact of sherardizing temperatures.

Phosphonic acid‐containing polysulfones as anticorrosive layers

ABSTRACTAs a part of research work to elaborate polymeric materials for metal corrosion protection, we have developed a new family of phosphonic acid‐containing polymers. The synthesis and the characterization of polysulfones bearing alkyl phosphonate ester side groups are first described. These polymers are synthesized by direct polycondensation of a phosphonate ester‐containing bisphenol by aromatic nucleophilic substitution. The physicochemical properties of the resulting polymers are described. Acidic hydrolysis of phosphonate esters results in the formation of phosphonic acid groups. A series of phosphonic acid‐containing polysulfones is therefore obtained and characterized. A preliminary evaluation of the anticorrosive properties of these polymers is described. In 0.25M Na2SO4 solution, the corrosion rate of a polymer‐coated mild steel sample is much lower than of the free metal substrate. These results suggest that phosphonic acid‐containing polysulfones might be interesting as anticorrosive coatings. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41890.

ChemInform Abstract: Controllable Fabrication of Nanostructured Materials for Photoelectrochemical Water Splitting via Atomic Layer Deposition

AbstractReview: 54 refs.

A nanoscopic approach to studying evolution in graphene wettability

The equilibrium state of graphene surfaces exposed to ambient conditions is of significant importance for applications from electronics to anti-corrosion layers and from a fundamental perspective. The environmental exposure influences macroscopic properties of the graphene surface, as recent studies on wettability reported. However, these studies are controversial for two reasons: firstly, time dependency of graphene wettability complicates comparison of results from different groups. Secondly it’s inherently difficult to understand the underlying physical phenomena by means of macroscopic measurements alone. Here we study the evolution of the wettability of graphene monolayers on copper by exposing samples to controlled ambient conditions. Static contact angle measurements reveal that the graphene undergoes a transition in its wettability from slightly hydrophilic to hydrophobic over timescales of the order of hours. To gain further insight, we apply Fourier transform infrared spectroscopy and a recently developed dynamic atomic force microscopy-based force spectroscopy to probe the sample surface at the nanoscale. This novel nanoscopic approach allows us to demonstrate that the transition in wettability of graphene is induced by the adsorption of water molecules from the environment in combination with hydrocarbon contamination. Furthermore, our nanoscale observations challenge the wetting transparency theory of graphene after exposure to the environment.

Application of Carbon Coated Stainless Steel for Bipolar Plate in Proton Exchange Membrane Fuel Cell

A polymer electrolyte membrane fuel cell (PEMFC) which uses stainless steel as a bipolar plate has many advantages over conventional machined graphite. Austenitic stainless steel 316L is a traditional candidate for metal bipolar plates. During a long operation time, metal oxide formation leads to contact resistance, and metal dissolution can cause contamination of the membrane electrode assembly (MEA). A pure Carbon was coated on the surface of Stainless steel and provided a good anticorrosion layer. The carbon film has a low area specific resistance compared to the composite coating because it has a high surface conductivity. In addition, The ICR between the carbon-coated SS316 and the carbon paper is 1100–3000 mΩ-cm2 under compaction forces between 20 and 280 N/cm2. The carbon-coated SS316L shows good corrosion resistance in the simulated PEMFC environment. After 4000hrs of testing time, the power density of a single cell was less than 1% decline. Therefore, the carbon-coated SS316L has an excellent durability property.

Application of Carbon Coated Stainless Steel for Bipolar Plate in Proton Exchange Membrane Fuel Cell

Stainless steel bipolar plates for the polymer electrolyte membrane (PEM) fuel cell offer many advantages over conventional machined graphite. Austenitic stainless steel 316L is a traditional candidate for metal bipolar plates.During a long operation time, metal oxide formation leads to contact resistance, and metal dissolution can cause contamination of the membrane electrode assembly (MEA). A pure Carbon was coated on the surface of Stainless steel and provided a good anticorrosion layer. The carbon film has a low area specific resistance compared to the composite coating because it has a high surface conductivity. In addition, The ICR between the carbon-coated SS316 and the carbon paper is 225–1247 mΩ-cm2 under compaction forces between 20 and 280 N cm−2. The carbon-coated SS316L shows good corrosion resistance in the simulated PEMFC environment. After testing the single cell for 4000hr, the power density was decay less than 1%. Therefore, the carbon-coated SS316L has an excellent durability property.Key words : fuel cell, carbon and bipolar plate

Preparation and characterization of anticorrosive layers deposited by micro-arc oxidation on low carbon steel

Different types of composite layers containing aluminum oxide have been deposited by micro-arc anodic oxidation of carbon steel S235 JR, using an aqueous aluminate solution containing 7g/l NaAlO2 and 2g/l NaOH.The layers were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), microanalysis and salt spray tests.The obtained layers contain aluminum oxide's polycrystalline phases (Al2O3-α and Al2O3-γ), are porous and have a thickness ranging from 3 to 11μm. It also has been observed that increasing the layer thickness also increases the concentration of Al2O3-α polycrystalline phase and the occurrence time of red salt (rust). The anticorrosion properties of the deposited layers are limited because of their porosity.

Formation of Fe-Al Intermetallic Compound Film on High-Speed Tool Steel by Shot Lining and Heat Treatment

Shot peening is widely utilized to improve the fatigue property of mechanical parts for transportation equipment such as cars and airplanes. Also, this technology is being applied as a film-forming technology in order to improve surface quality. The authors have recently proposed new joining methods using shot peening, shot lining. In this method, the metals are bonded with the dissimilar metal by applying plastic deformation and the pressure. The thin foil can be joined to the substrate surface by the pressure generated by the hit of the shots. In this study, the formation of an Fe-Al intermetallic compound film on high-speed tool steel by shot lining and heat treatment was investigated. In the experiment, a centrifugal-type peening machine with an electrical heater was employed. The shot medium was high-carbon cast steel. The substrate was a commercial high-speed tool steel JIS-SKH51, and the foil was commercially available pure aluminium. The shot lining process of tool steel with an aluminium foil was carried out at 573K in air using a peening machine. Heat treatment was performed at diffusion temperatures from 923 to 1573K in vacuum. The lined substrates exhibited a harder layer of aluminium-rich intermetallics in the diffusion temperature range of 923 to 1173K. When the temperature of the lined substrates was more than 1273K, the surface was covered with thicker and highly anticorrosive layers of iron-rich intermetallics. We found that the present method could be used for the formation of functional films on high-speed tool steel.

Anodic-modified anticorrosive coatings

Steel machine parts are exposed to electrochemical corrosion. This applies to many environments including atmosphere, soil, water, and even various fertilizers. High-carbon steel and low-alloyed steel are not stable (in terms of thermo-dynamics), do not feature effective passivation, and even the corrosion products do not form a stable protection layer. As a result, special anti-corrosion protection is critical. In heavy-corrosion environment, paint systems containing Zn have proven to be very effective. Presented text describes verification of paint systems with high Zn content and compares them to galvanic Zn coatings. Steel samples with protective coatings have been tested in condensation chamber with neutral salt-spray. This way, corrosion resistance of Zn-rich paint systems and galvanic Zn coatings has been evaluated and compared. Galvanic Zn-coatings have shown complete decomposition during the chamber exposition. Thus, further testing was adopted for paint systems only with a special attention being paid to gradual degradation of anti-corrosion layer. Final part of the text lists reasons of coating degradation process and outlines possible solutions of the issue.

Controllable fabrication of nanostructured materials for photoelectrochemical water splitting via atomic layer deposition

Photoelectrochemical (PEC) water splitting is an attractive approach to generate hydrogen as a clean chemical fuel from solar energy. But there remain many fundamental issues to be solved, including inadequate photon absorption, short carrier diffusion length, surface recombination, vulnerability to photo-corrosion, and unfavorable reaction kinetics. Owing to its self-limiting surface reaction mechanism, atomic layer deposition (ALD) is capable of depositing thin films in a highly controllable manner, which makes it an enabling technique to overcome some of the key challenges confronted by PEC water splitting. This tutorial review describes some unique and representative applications of ALD in fabricating high performance PEC electrodes with various nanostructures, including (i) coating conformal thin films on three-dimensional scaffolds to facilitate the separation and migration of photocarriers and enhance light trapping, as well as realizing controllable doping for bandgap engineering and forming homojunctions for carrier separation; (ii) achieving surface modification through deposition of anti-corrosion layers, surface state passivation layers, and surface catalytic layers; and (iii) identifying the main rate limiting steps with model electrodes with highly defined thickness, composition, and interfacial structure.

Formation of bioactive anticorrosion coatings on resorbable implants by plasma electrolytic oxidation

Calcium phosphate coatings (Ca/P = 1.61) containing magnesium oxide MgO and hydroxyapatite Ca10(PO4)6(OH)2 accelerating the growth of bone tissue have been prepared by the method of plasma electrolytic oxidation (PEO) on MA8 magnesium alloy. The phase and element compositions, morphology, and anticorrosion properties of coatings were investigated. Such PEO layers were found to essentially reduce the corrosion rate of magnesium alloy (polarization resistance being increased by two orders). This makes it possible to consider the formed PEO coatings as likely anticorrosion layers for medical bioresorbable implants.

Investigation on the Anti-Corrosion Layer of the Power Transmission Steel Structures

The power transmission steel structures are used in the outdoor and the durability will be decreased due to the various corrosions, so the structures usually coated the anti-corrosion layers such as hot-dip coating, zinc-rich coating or thermal spray zinc coating. The anti-corrosion layers on three power transmission steel structures in Henan province, China were investigated by the corrosion morphology and the residual coating thickness. The results indicated that the corrosion degree of the bolts is higher than that of the steels, and there are local corrosions occurred on the surface of the steels due to the plating leakage or clash.

Selection of Anticorrosion Adhesive Layer for Steel Deck

In order to solve the problems of the pavement delamination or slip caused by the failures of waterproof adhesive layer or anti-corrosion coating, the epoxy zinc-rich paint, the epoxy clear water paint and epoxy asphalt adhesive material with good performance was selected for the roughness-adhesive force test, tensile test under different temperatures and corrosion resistance test. The optimal anti-corrosion layer and adhesive layer were selected to increase the service life of the steel deck pavement. The test results show that: When the steel roughness is 60μm, the anti-corrosion material has the highest adhesive strength with the steel plate. Both the epoxy zinc-rich paint and the epoxy water paint have high adhesive strengths with the steel plate at room temperature. But at low temperature, the adhesion performance of the epoxy water paint is significantly better than that of the epoxy zinc-rich paint. At 70 °C, the adhesive strengths of both the epoxy water paint and epoxy zinc-rich paint adhesive system greatly decrease. The destruction morphology shows the opening of the adhesive layer. The specialized anti-corrosion coating must be brushed on the steel deck.

A Comprehensive Parametric Finite Element Study on the Development of Strain Concentration in Concrete Coated Offshore Pipelines

The strain concentration at the field joint (FJ) of the commonly used concrete coated offshore pipelines is considered and discussed in this paper. The details of a 3D finite element (FE) modeling framework, developed using the commercial software ABAQUS, are presented. The numerical results are verified against the experimental results available in the literature. The FE model considered in this study captures several nonlinear phenomena associated with the problem, including the plastic deformation of the steel and anticorrosion layer (ACL) material, the cracking and crushing of the concrete, and also the large deformation effects. The developed FE framework is subsequently used to perform a parametric study to assess the effect of each influencing parameter on the strain concentration factor (SCF) developed within the FJ region. The influence of the geometric features of the coated pipe and the relevant mechanical properties of the materials as well as various combined loading scenarios are investigated. Results indicate that pipeline diameter, thickness, and coating thickness affect the SCF more than the strength of either concrete coating or ACL. Also, the postyield properties of the steel, especially the strain hardening capacity, may significantly influence the SCF. The combination of the internal pressure loading (causing a biaxial stress state) or tensile loading with the primary bending load is found to also increase the SCF significantly after steel yielding is initiated. Moreover, these combined loading scenarios cause different and more severe plastic deformation patterns in the FJ.

Formation of Fe-Al Intermetallic Compound Film on Carbon Steel by Shot Peening and Heat Treatment

The formation of an Fe-Al intermetallic compound film on carbon steel by shot lining and heat treatment was investigated. In the experiment, a centrifugal-type peening machine with an electrical heater was employed. The shot medium was high-carbon cast steel. The substrate was a commercial carbon steel, and the sheet was commercially available pure aluminum. The shot lining process of carbon steel with an aluminum sheet was carried out at 300 °C in air using a peening machine. Heat treatment was performed at diffusion temperatures from 600 to 1050 °C in vacuum. The lined substrates exhibited a harder layer of Al-rich intermetallics, such as Fe2Al5, in the diffusion temperature range of 650 to 900 °C. When the temperature of the lined substrates was more than 930 °C, the surface was covered with thicker and highly anticorrosive layers of Fe-rich intermetallics, such as FeAl and Fe3Al. We found that the present method could be used for the formation of functional films on carbon steel.

Anti-Corroded Molybdenum Back Electrodes by Al Doping for CuIn1-xAlxSe2 Solar Cells

The effects of Al doping into Mo films, used as back electrodes of CuIn1-xAlxSe2 solar cells, were systematically investigated. The Mo1-XAlX films fabricated by co-sputtering were exposed in a damp-heat (DH) chamber with 85°C and 85% relativity humidity for 168 h to verify the reliability. The resistivity of the Mo79Al21 films after DH exposure was only slightly increased from 2 × 10−6 Ω m to 2.3 × 10−6 Ω m; however, the pure Mo films after DH exposure became insulating due to the formation of the MoOx layer. Based on the analyses of the x-ray diffraction and x-ray photoelectron spectrum, we suggest that the Al atoms are dissolved into the Mo films in the as-deposited state and segregate to the surface of Mo1-XAlX films during DH exposure. A thin Al-oxide layer is formed on the surface and behaves as an anti-corrosion layer, which enhances reliability. On the other hand, with increasing the Al content, increased amount of the Al2O3 layer may suppress the formation of the MoSe2 layer at the interface between Mo and CIS-based films. Consequently, the Mo film with the optimized Al doping, for example, the Mo79Al21 film may become a good candidate of the back electrode for CuIn1-xAlxSe2 solar cells to maintain good reliability as well as to achieve good adhesion and low series resistance.

Corrosion Performance of Hot Dip Galvanized Steel

A method of EIS measure-polarization-relaxation was used to investigate the corrosion performance of different hot-dip coating layers of galvanized steel. The result showed that the corrosion of hot dip galvanized steel was divided into four phases, and the corrosion of each phase was corresponded to different layer respectively. The anti-corrosion difference of every layer was very distinct. The optimal anti-corrosion layer of hot dip galvanized steel was δ phase. This method could be used to detect coating corrosion quickly.

Nitriding Treatment of Reduced Activation Ferritic Steel as Functional Layer for Liquid Breeder Blanket

The development of functional layers such as a tritium permeation barrier and an anti-corrosion layer is the essential technology for the development of a molten salt type self cooled fusion blanket. In the present study, the characteristics of a nitriding treatment on a reduced activation ferritic steel, JLF-1 (Fe-9Cr-2W-0.1C) as the functional layer were investigated. The steel surface was nitrided by an ion nitriding treatment or a radical nitriding treatment. The nitridation characteristic of the steel surface was made clear based on the thermodynamic stability. The thermal diffusivity, the hydrogen permeability and the chemical stability in the molten salt Flinak were investigated. The results indicated that the nitriding treatment can improve the compatibility in the Flinak without the decrease of the thermal diffusivity, though there was little improvement as the hydrogen permeation barrier.

Effect of conditions of treatment with superdispersed polytetrafluoroethylene on properties of composite coatings

A purposeful selection of the number of layers and the treatment temperature depending on the used fraction of superdisperced polytetrafluoroethylene (SPTFE, the Forum trademark) provides a maximum penetration of the polymer into pores and the formation of a uniform and continuous film on the surface. This information is of crucial importance for obtaining composite, including multifunctional, protective (antiscale and anticorrosion) layers on titanium products that operate under different temperature conditions in aggressive chloride-containing environments.