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The purpose of this study was to investigate the corrosion of low molecular organic acids from water-steam cycles such as acetic acid and formic acid in mental parts of steam turbine initial condensation zone.

The corrosion behavior of gray cast iron in initial condensate containing different concentrations of acetic acid and formic acid was studied by weight loss test, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction.

The results indicated that gray cast iron had a certain degree of corrosion in the simulated initial condensate containing acetic acid and formic acid, but the acid corrosion of gray cast iron was not only caused by low molecular organic acid but also affected by inorganic anions such as Cl⁻. When Cl⁻ existed, after removing corrosion products, surface analysis results proved that the surface of gray cast iron was rough and uneven with many cracks, which was corrected more serious.

The corrosion behavior of thermal equipment by low molecular organic acids and inorganic anions in water-steam cycles was studied. The research results can provide theoretical guidelines for corrosion control of steam turbine in power plants.

Considers the advantages of highly alloyed stainless steel such as duplex stainless steels or nickel‐based alloys in highly corrosive environments. Looks at corrosion rates for alloys in acetic acid and presents results of tests on the influence of contaminants in the acid. Gives practical applications. Concludes that duplex stainless steels demonstrate higher corrosion resistance than austenitic stainless steels and are often comparable to nickel base alloys.

The purpose of this paper is to supplement the scant previous investigations on the corrosion behaviour of 2205 and 2507 duplex stainless steels in selected organic acids containing chloride additions.

Microstructural examination of the alloys was first carried out, after which the corrosion behaviour of the alloys in citric, oxalic, formic and acetic acids containing chloride additions at varying temperatures was studied using electrochemical techniques.

The alloy 2507 material had a larger grain size than did the alloy 2205 sample. The corrosion resistances of the alloys generally are highest in acetic acids and lowest in citric acid. The addition of chloride had a pronounced effect on their corrosion resistance. Alloy 2507 generally exhibited higher corrosion resistance in all of the acids than alloy 2205, with the exception of acetic acid at room temperature. The 50:50 ratio of ferrite to austenite composition, as revealed by phase compositional analysis, indicated no significant possibility for galvanic corrosion between the phases. This suggests that the corrosion behaviour of the alloys is controlled by their grain sizes and chemical compositions.

Although the corrosion behaviour of duplex stainless steels in some organic acid media has been reported, this investigation covers the major organic acids not previously reported. Since in real industrial systems a mixture of both organic and minerals acids/salts may typically exist, investigations of the combined effect of chloride ions with the organic acids reported in this paper typify real industrial operations. The paper thus provides a basis for material selection for the application of 2205 and 2507 in industrial systems where organic acids are mostly used.

Introduction A standard formulation of paint stripper based on dichloromethane will contain an activator to promote the rate of solvent action, either an acid—especially formic acid—or an amine such as ethanolamine. A frequent method of application is to arrange the components on jigs or in baskets, followed by immersion in stripping solution subsequently flushing off the loose paint by water jets. To minimize loss of volatile dichloromethane the immersion tank carries a water seal floating on the surface of the organic phase.

The following report was brought up by Dr. P. Brouardel, Dean of the Faculty of Medicine of Paris, President of the Commission, and was submitted for the approval of the Congress:

Generally, of all the properties, corrosion resistance can be a prime consideration in determining whether a given alloy or metal is adequate for a proposed use. With the increasing ability to fabricate many alloys and metals into fibre material of extremely small diameter, a better knowledge of their chemical properties as related to their unique size becomes more essential since many of the potential applications involve exposure to corrosive environments. This article reviews the corrosion resistance of Brunsmet MF‐A1 stainless steel fibres produced by the Brunswick Corp., Chicago, Illinois.

Pentaerythritol is a synthetic polyalcohol with the formula C 2OH)4, obtained in the reaction of one acetaldehyde molecule with four molecules of formaldehyde. This reaction takes place in a dilute aqueous solution in the presence of alkaline catalysts. Besides the pentaerythritol a salt of formic acid, most often sodium formate, is the by‐product obtained.

Plant development and use as green corrosion inhibitors are already recognized as one of the most environmentally friendly and effective protocols. In recent years, efforts have been made to find green corrosion inhibitors as an alternative to synthetic inhibitors for metals in acid medium. This paper aims to report the investigation of use of aqueous extracts of Tamarindus Indica as green inhibitors for corrosion of metals within different circumstances.

The use of Tamarindus Indica extracts (leaves, stem, fruit pulp and fruit husk) as corrosion inhibitors for mild steel and aluminum in different mediums (HCl, H2SO4, formic acid and citric acid) at different temperatures was investigated.

The inhibitory efficiency of Tamarindus Indica extracts increases with increasing concentration and decreases with increasing temperature. Langmuir is the adsorption isotherm, and the extract (inhibitor) is a mixed-type inhibitor (physisorption and chemisorption).

Tamarindus extracts (leaves, stem, fruit pulp and fruit husk) are effective inhibitors and can be used to protect metals from corrosion at different circumstances.

To the best of the authors’ knowledge, this is the first review that discusses the use of Tamarindus Indica extracts as corrosion inhibitors for metals.

When providing substitutes for CFC‐113 in processes such as vapour phase soldering and removal of flux residues after soldering in the electronics industry, it is also important to avoid the use of other organic solvents at the same time. Vapour phase soldering can be replaced by soldering in an infra‐red belt oven or by using a closed wave soldering system with an inert gas such as nitrogen. The use of organic solvents in the removal of flux residues can be replaced by the following three procedures: eliminating removal, by using a flux with a low residue content; eliminating removal, by using a flux such as adipic acid (and formic acid) in a closed wave soldering system with an inert gas such as nitrogen; and removal with water using a water‐soluble flux.

The paper presents the results of measuring the diffusion processes in epoxy resins based on bisphenol A and bisphenol S hardened with aromatic polyamines. The effects acting on the diffusion of acids into the resins thus hardened are discussed. These involve mostly the diffusion processes of solutions connected with a chemical reaction affecting the chemical stability of material. The chemical resistance of epoxy resins is affected by the molecular weight and type of epoxy resin, the polyamine functionality, the polyamine concentration, and the kind of plasticizer. The measurements performed by a microscopic method gave the values of diffusion coefficients relating to the penetration of some inorganic and organic acids into the epoxy resin based copolymers.