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The purpose of this study was to investigate the corrosion of rusted carbon steel in dilute NaCl solution, with the purpose of exploring the effect of the rust layer on metal corrosion and establishing a corrosion model for rusted iron.

The corrosion behavior of rusted carbon steel in dilute NaCl solution was studied by means of weight-loss determinations, scanning electron microscopy, Raman spectrometry and electrochemical techniques.

The results indicated that carbon steel had a similar corrosion behavior in all three NaCl solutions. The iron rust, which consisted of a thin γ-FeOOH layer and a thick Fe₃O₄ layer, can facilitate the corrosion process of carbon steel via reduction of γ-FeOOH and the large area cathode of Fe₃O₄. Hence, the corrosion rate of carbon steel was accelerated significantly and finally was determined by the limiting diffusion rate of oxygen.

A corrosion model of rusted carbon steel was established, suggesting that iron rust formed in all slightly acidic waters with low alkalinity probably promotes the corrosion of carbon steel. Anti-corrosion measures for iron in this type of solution, such as desalination water, should be aimed to reduce the promotional effect of the rust layer on metal corrosion.

It is shown that complete derusting of structural steel is not necessary if rust converter which can convert adherent rust into a protective coating is used. The performance of the rust converter developed by the authors is described in this paper.

The purpose of this investigation was to study the effects of sodium hexametaphosphate and zinc sulfate on the corrosion control of rusted iron in reverse osmosis (RO) product water of seawater.

The synergistic effects and inhibition effects of corrosion inhibitors on rusted carbon steel were studied using the weight-loss method, electrochemical tests and surface analysis techniques.

The results indicated that sodium hexametaphosphate could partly suppress the corrosion of rusted steel, but zinc sulfate used alone had no inhibition effect. Hexametaphosphate and zinc sulfate showed a strong synergistic effect and the optimal ratio of two chemicals was 1:1. The inhibition efficiency appeared to increase with increasing inhibitor concentration and the ideal dosage of inhibitors was set at 20 mg/L, when chemical cost and inhibition efficiency were taken into account. Surface analysis results proved that this compound inhibitor could make the rust layer much more compact. The inhibitive mechanism was to combine with rust and form a protective film, which consisted of iron oxide, polyphosphate and Zn(OH)₂.

It was found that the compound inhibitor consisting of sodium hexametaphosphate and zinc sulfate had a good inhibitive effect on rusted iron in RO product water. The research results can provide theoretical guidelines for corrosion control of rusted pipes in power plants.

The purpose of this paper is to explore the long‐term corrosion behavior of carbon steel in 3% NaCl solution and evaluate the effect of rust layer on the corrosion process.

The corrosion behavior of rusted carbon steel in 3% NaCl solution was studied by means of infrared spectroscopy (IR) and electrochemical impedance spectroscopy (EIS).

The results indicated that the corrosion of carbon steel was affected by chloride ion in initial immersion and then controlled by the rust layer. The rust layer consisted of a thin outer layer (γ‐FeOOH layer) and a thick inner layer (Fe₃O₄ layer). The outer rust layer facilitated the cathodic process via reduction of γ‐FeOOH, while the inner rust layer provided a large cathode area and oxygen could be reduced on its surface. As a result, the corrosion rate of carbon steel was determined by the limiting diffusion rate of oxygen and stabilized at a high value.

The corrosion model of rusted carbon steel in 3% NaCl solution was established. It is probable that the iron rust in all slightly acidic water with low alkalinity can promote the corrosion process via reduction of γ‐FeOOH. Anti‐corrosion measures for iron in this type of solutions should be aimed to reduce the promoting effect of rust layer on the metal corrosion. The NaCl solution prepared from tap water is more suitable for the substitution of artificial water than that prepared from deionized water.

This article examines how smallholders in Oaxaca, Mexico, experienced and responded to the recent coffee rust disaster, asking whether fair trade coffee producer organizations helped smallholders develop coping mechanisms to offset their vulnerability. It demonstrates how Oaxacan coffee producers were especially vulnerable during the recent rust outbreak due to long-term trends including a decline in governmental support for the sector dating back to the 1990s which resulted in a decline in producer incomes and a concomitant rise in the number of aging and poorly managed coffee plots that were more susceptible to coffee rust. The ongoing price volatility within coffee commodity markets and the continued restructuring of the specialty coffee market also increases the uncertainty producers face when determining how to best respond to the rust disaster. The article details the concrete ways in which fair trade coffee producer organizations help bolster the adaptive capacity of their members, while also noting areas for improvement.

The rust inhibiting characteristics of barium/calcium petroleum sulphonates, prepared from two indigenously available base stocks of different origin have been determined in concentration ranging from 0.5 to 3.0% W/W in mineral oil as per ASTM D‐1748 method. The products have been characterised as ‘outstanding’, ‘good’ and ‘satisfactory’ on the basis of their performance in the humidity cabinet. It has been observed that Ba/Ca petroleum sulphonates possessing outstanding rust inhibiting characteristics show low oil/water interfacial tension and high water solubilization characteristics as compared to other sulphonates. It has also been observed that the rust inhibiting characteristics are profoundly influenced by the structural parameter of the hydrocarbon portion of the petroleum sulphonates. The larger the alkyl side chain, the better is the rust inhibiting properties.

The purpose of this paper is to study the ability of commercial tara powder to convert rust into iron tannate and evaluate their use as raw material for the formulation of water based rust converter.

Water-borne acrylic primers were formulated with tara powder and aqueous tara extract and applied on steel rusted by three different methods. The conversion of rusted steel by tara tannins was studied by X-ray diffraction spectroscopy, infrared spectroscopy and scanning electron microscopy. The acrylic primers, containing hydrolysable tannins, were coated with alkyd finish and were evaluated in comparison to commercial systems in accelerated corrosion tests. The corrosion inhibition effects of tara powder on mild steel in 0.1M NaCl were studied by DC electrochemical techniques.

Tara tannin converts rust to ferric tannate and increases the magnetite content of rusted steel. The water-based acrylic primer formulated with aqueous extract of tara, alkyd-coated finish, showed performance equivalent to pure alkyd system.

The chlorides content in the commercial tara powder can be screened the beneficial effect of hydrolysable tannins to convert rust. Furthermore, the water-based rust converter formulated with acrylic resin may be sensitive to salt contamination of rust.

Hydrolysable tannins from commercial tara powder have not been studied yet in its application to the development of rust converters. A water-based primer formulated with commercial tara powder developed for the effective treatment of rusted surfaces can be of interest as an environmentally friendly to current commercial approaches.

To identify a method of evaluation as well as conditions under which corrosion in the form of flash rusting attacks steel treated with a coating of water‐borne binders.

The paper worked with soluble alkaline silicates – sodium silicate – acting as flash rusting inhibitors, while aqueous dispersion binders were used in primer paints. Sodium silicate, potassium silicate and lithium silicate were studied from this point of view. Their inhibiting properties were described with the aid of a scanning method, determination of metal weight loss and electron raster microscopy.

Sodium silicate was identified as a very good flash rusting inhibitor for applications in styrene‐acrylate water‐borne paints.

Sodium silicate, potassium silicate and lithium silicate can be used in industrial coatings as high‐performance inhibitors of flash rusting.

A coating containing corrosion defects occurring during the creation of a film loses its anticorrosion properties and provides only low anticorrosion protection against atmospheric corrosion when the film of coating is later exposed to a corrosion environment. This paper proved that silicates could be very efficient flash rusting inhibitors under certain conditions.

THE adaptation and application of the cumulative experience of practical and theoretical research to the problems of industry has led to the solving of many of its problems and the linking up of industries of very diverse natures. Materials, processes, and mechanisms have been developed in many instances to an almost perfected state, leading to an economy in power consumption, reduced production costs, greater efficiency of the unit, and increased service life. Yet the protection of materials, particularly metals, employed in industry has not revealed itself to the same extent, more because of the enormity of the field of application than lack of development in this direction.

This paper aims to prepare a residual rust epoxy coating by adding different quantities of phytic acid (PA) on the surface of the rusty steel and investigate the corrosion protection of PA and its action mechanisms.

A residual rust epoxy coating by adding different quantities of PA was prepared on the surface of the rusty steel. The influence of PA on the corrosion resistance of epoxy-coated rusty steel was investigated by means of electrochemical impedance spectroscopy and adhesion testing.

Results indicated that PA can substantially improve the corrosion resistance of epoxy-coated rusty steel. This improvement is due to the reaction of PA with residual rust and generation of new compounds with protection properties and increased adhesive strength effects on the coating/metal interface. The coating showed better protection performance when 2 per cent PA was added.

Considering the structure of the active groups, PA has strong chelating capability with many metal ions and can form stable complex compounds on the surface of a metal substrate, thereby improving corrosion resistance. In recent years, PA has been reported to be useful in the conversion of coatings or as green corrosion inhibitor. To the best of the authors’ knowledge, few studies have reported the use of PA as a rust converter or residual rust coating. The present work aims to improve the corrosion resistance of residual rust epoxy coating by adding PA.