Anti-corrosion Film Research Articles

Preparation of anti-corrosion films by microarc oxidation on an Al–Si alloy

Thick ceramic films over 140 μm were prepared on Al–7% Si alloy by ac microarc oxidation in a silicate electrolyte. The film growth kinetics was determined by an eddy current technique and film growth features in different stages were discussed. The microstructure and composition profiles for different thick films were analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy. Their phase components were determined by X-ray diffraction. The electrochemical corrosion behaviors of bare and coated alloys were evaluated using potentiodynamic polarization curves, and their corrosion morphologies were observed. In the initial stage of oxidation, the growth rate is slow with 0.48 μm/min due to the effect of Si element though the current density is rather high up to 33 A/dm 2. After the current density has decreased to a stable value of 11 A/dm 2, the film mainly grows towards the interior of alloy. The film with a three-layer structure consists of mullite, γ-Al 2O 3, α-Al 2O 3 and amorphous phases. By microarc discharge treatment, the corrosion current of the Al–Si alloy in NaCl solution was significantly reduced. However, a thicker film has to be fabricated in order to obtain high corrosion-resistant film of the Al–Si alloy. Microarc oxidation is an effective method to form an anti-corrosion protective film on Si-containing aluminum alloys.

Loading of soil-covered oil and gas pipelines due to adverse soil settlements – Protection against thermal dilatation-induced wear, involving geosynthetics

Oil and gas pipelines covered with a mixture of sandy gravel and square-edged stones are subjected to abrasive shear loading steming from temperature-induced displacements of the pipeline in longitudinal direction. This requires wear protection of the outer anti-corrosion film of such pipes. In order to assess appropriate means for protection, adverse settlements on both sides of the soil-covered pipeline are assumed as relevant loading scenario. A nonlinear, elastoplastic, cap model-based Finite Element model delivers the radial stresses exerted onto the pipeline, due to settlement-induced load re-arrangement within the cohesionless soil body. Given a cover height of 1.5 m, the aforementioned load re-arrangement leads to an increase of force action onto the pipe by up to 200%. Based on the grain size of the filling material, radial stresses are integrated as to estimate the maximum normal forces exerted by single stone corners onto the pipe’s anti-corrosion film. These forces, when analyzed through Archard’s law, allow for calculation of the service life of the protection layer enveloping the pipe, once the wear resistance of that layer is determined from experiments, as is done for geosynthetics. Since the service life of a geosynthetic protection layer of the anti-corrosion film turns out to be distinctively smaller than the standard service life of a soil-covered steel pipeline, protection through geosynthetic layers is insufficient. Hence, more effective means for protection are suggested.

PIXE Spectroscopy for Determination of Volatile Corrosion Inhibitor Concentration in Anticorrosion Polymer Films

Anti-corrosion polymer films used for 0 to 6 years were investigated to determine the type and content of volatile corrosion inhibitors (VCI) and how long the films emit it to protect the metal surface encased by the film. By FTIR and DSC low density polyethylene (LDPE) was identified as the polymer carrier. Particle induced X-ray emission (PIXE) spectroscopy of anti-corrosion polymer films revealed significant concentration of molybdenum implying that corrosion inhibitor was molybdate based. The films were divided into three groups according to different rate of the VCI concentration decrease with increasing age. The division of films into groups and diffusion of VCI was confirmed by significant decrease of Mo content determined by PIXE spectroscopy after accelerated ageing in vacuum at 50°C. It was concluded that films with initial concentration of Mo above 6000 ppm emit VCI for at least 6 years while the films with less than 4000 ppm of molybdenum do not emit the VCI in the ambient conditions.

Anti-corrosion film on 2024/SiC aluminum matrix composite fabricated by microarc oxidation in silicate electrolyte

A corrosion-resistant ceramic film was prepared on the SiC reinforced aluminum matrix composite by microarc oxidation technique in silicate solution. The film with two layer structure consists of mullite, α-Al 2O 3, γ-Al 2O 3 and amorphous SiO 2. Analysis of microstructure and composition suggests that only a few SiC particles remain in the film close to the composite/film interface and most of SiC reinforcements have transformed into the oxides under plasma discharge sintering. By microarc oxidation treatment, the corrosion current density of 2024/SiC decreases almost four orders of magnitude. The corrosion resistance of the coated 2024/SiC composite was greatly improved because the SiC reinforcements had not disrupted the continuity of micoarc oxidation film.

402 イオン溶出・拡散現象を利用した表面改質加工法の研究開発(OS-12 ELID加工)

The reaction layer at the surface of processed work has conventionally been perceived negatively as a sub-surface damage layer. However, in a recent study, the authors clarified that the ultra precise mirror surface finishing method could modify the work surface during grinding (removal process). This method is expected to produce various effects such as inducing an oxidization reaction on an active new surface immediately after processing, to thereby coat the surface with an anti-corrosion film, advantageously transforming the components of the tool or grinding fluid to the surface. This paper discusses applications of these latest techniques.

Host-Guest Systems in the Development of Anticorrosive Polymeric Films

ABSTRACTInteractive dispersion-type LDPE/EVA films with anticorrosive properties were produced using host-guest systems of thermally stable volatile corrosion inhibitors (VCI) dicyclohexylammonium p-nitrobenzoate and phosphate, adsorbed on NaY zeolites and diatomaceous earths. Carbon steel specimens were either directly exposed to the inhibiting systems studied or wrapped with the additivated films. Accelerated corrosion tests were carried out where the inhibitive properties of the systems being studied were determined by mass loss of the test coupons. The influence of the mineral support on the volatility of the corrosion inhibitors was evaluated by TG/DTG techniques. The obtained results may be regarded as a confirmation of the hypothesis that VCI volatility may be controlled by their deposition on determined supports. Also, both VCIs had their efficiency enhanced by zeolites, and the phosphate greatly benefited from the use of diatomaceous earth.

ChemInform Abstract: Anticorrosion Film of Benzimidazole on Brass in Ammonia.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Anticorrosion Film of Benzimidazole on Brass in Ammonia

Anticorrosion Film of Benzimidazole on Brass in Ammonia

Advanced Boron Soaking Procedure for Steam Generators.

An experimental study on boric acid penetration into the crevices between tube and tube-support-plate, and intergranular-attack (hereinafter called IGA) cracks in crevices has been performed to obtain the optimum boron soaking procedure in operating steam generators with IGA. is a corrosion mechanism involving the dissolution of the metal grain boundary. It consists of several cracks which propagate along metal grain boundaries from the outer surface to the inside of the tube. The term IGA crack refers to these cracks. Two experimental crevice models were set up. One was of the packed-crevice type where the crevice gap is completely packed by sludge, and the other was of the open-crevice type where the crevice gap is not packed, but reduced by sludge. The boron in cracks was investigated using ion microanalysis in order to confirm the existence of anticorrosive film in propagation. The optimum reactor power for effective boric acid penetration into the tube surface and into the cracks within the crevice was found to be a power level of about 5% and 30%, which are applicable to both the packed-and open-crevice types.

Marine anticorrosion paints

Four paint compositions were prepared, two of them based on vinyl copolymer as a binder and the other contain boiled oil in presence or absence of soluble resin material. Boiled oil based paints meet the most anticorrosion action and film property. Also, the anticorrosion potential of the paints depend on the type of ingredients and their ratio in the dry paint films.

The formation of an effective anti-corrosion film on copper surfaces from 2-mercaptobenzimidazole solution

The formation of an effective anti-corrosion film on copper surfaces has been achieved by immersion of a chemically cleaned copper plate into a solution of 2-mercaptobenzimidazole in ethanol. This film is extremely stable as compared with the anti-corrosion layer formed on an oxidized surface. The formation mechanism and the structure of the inert film have been investigated by the use of infrared and X-ray photoelectron spectroscopy. Its anti-corrosion characteristics in several media were investigated by the use of cyclic voltammetry.

低エネルギー光電子による銅表面防食皮膜の評価

低エネルギー光電子による銅表面防食皮膜の評価

Anti-corrosion thin protective film for vacuum deposited Co-Ni-O layers

This paper develops ca. 10nm thick anti-corrosion plasma polymerization coating for vacuum deposited Co-Ni-O magnetic recording layer. Corrosion resistance of the coated magnetic tape varied with the change of monomer species and plasma conditions. Among many samples, butadiene plasma polymer coated by a suitable plasma process showed excellent corrosion resistance. In order to make clear the cause of the variation, the following two investigations were performed: (1)Plasma Exposure Degree during the coating was introduced as a process parameter and (2) ESCA was utilized to find the atomic composition and the structure of plasma coating. The low PED process and low oxygen content at the bottom of the plasma polymer layer corresponded to excellent resistance. It was the oxygen atoms from Co-Ni-O that gave rise to poor corrosion resistance of plasma polymer coated samples.

さび止め塗料の膜厚

さび止め塗料の膜厚