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This article presents the galvanostatic anodic oxidation of two types of stainless steel alloys, ferritic (15.03% Cr) and austenitic (20.45% Cr, 8.37% Ni), in molten NaNO₃‐KNO₃ eutectic mixture at different temperatures ranging from 673‐873K. At a temperature of 673K the shape of polarization curves for the alloys is complex, while at higher temperatures it is simple. The passivity potential range was calculated as the difference between the passivation potential, E_p, and the breakdown potential, E_b. The value of E_b – E_p decreases with the increase of temperature. The amount of iron, chromium and nickel dissolved in the melt was determined after each experiment using atomic absorption spectroscopy. The composition and structure of the corrosion products formed on the surface of electrodes were examined by X‐ray diffraction analysis. Corrosion parameters derived from the polarization curves are calculated; these are: polarization resistance at low current densities, R_p, exchange current density, i_o, corrosion current density, i_corr, passivation current density, i_p. It was found that the increase of temperature increases i_o, i_corr, and i_p while R_p, decreases. From these results it was found that, under the given conditions, the austenitic stainless steel alloy is more corrosion resistant than the ferritic one. The activation energy of corrosion was estimated for the two alloys.

The corrosion behaviour of a ferritic (alloy 1) and two austenitic stainless steel alloys (alloys 2 and 3) was studied in a molten Li₂CO₃‐Na₂CO₃‐K₂CO₃ ternary mixture in the presence of Na₂O₂ additions at temperatures of 475, 500, 525 and 550°C. The techniques of measurements were open circuit potential, galvanostatic anodic polarisation and cyclic voltametry. The addition of Na₂O₂ increased the concentration of oxide ions in the carbonate melt. There is a tendency for oxidation and passivation of the alloys to commence immediately on their immersion in the melt, and end at the passivity breakdown, where the decomposition of carbonate ions occurs with the formation of CO₂ and O₂ gases. The oxide scales of a ferritic alloy are less protective than those formed on the austenitic alloys. The oxide scales, in most cases, are multilayered, and the presence of Na₂O₂ in the carbonate melt gives rise to the formation of a more protective inner layer of oxide scales on the surface of the austenitic alloys.

Compares the corrosion behaviour of Ti6Al4V titanium alloy, a conventional duplex stainless steel (UNS 31803) and AISI 304 austenitic stainless steel in synthetic biofluids using electrochemical techniques and comments on the suitability of DSS for use in biomedical applications. Finds that the general corrosion resistance of duplex stainless steels is slightly inferior to that of austenitic stainless steel and titanium alloy; duplex stainless steel does not show any sign of pitting when exposed to synthetic biofluids and exhibits excellent resistance to localised corrosion on par with that of titanium alloy. Concludes that duplex stainless steels are one of the best alternates to titanium alloys.

The corrosion behaviour of low alloy steel type AISI 4130 (before and after nitriding) and austenitic stainless steel type AISI 304L were studied in tap water +3.5 per cent NaCl. A liquid nitriding process had been applied on the low alloy steel.

The tests that were carried out in this study were anodic polarization, rotating bending fatigue and axial fatigue using compact tension (CT). For determining the corrosion potential and pitting potential (breakdown potential) for the alloys, anodic polarization curves were established using the potentiodynamic technique. Rotating bending fatigue tests were used to calculate the fatigue strength and damage ratio. Using linear elastic fracture mechanics, the CT specimens were prepared for determining the threshold stress intensity factor, fatigue crack growth rate and fracture toughness in air and in the solution.

The results showed that nitrided specimens showed higher fatigue strength in air compared to stainless steel. However, the corrosion fatigue limit for both these samples were approximately equal, while this limit for non‐nitrided sample was less. Moreover, the non‐nitrided steel had lower corrosion and pitting potentials than did the stainless steel. In addition, the CT tests showed that the nitrided specimens had a lower resistance to crack initiation in air and the solution compared to the non‐nitrided sample and the stainless steel.

These results can be attributed to the chemical and mechanical behaviour of the nitrided layer constituents, mainly FeN and CrN, which were recognized by X‐ray diffraction. Since, these components consist of very hard particles, they act to increase the hardness and fatigue limit. Moreover, due to the low conductivity of these nitrides, the corrosion and pitting potential of the nitrided steel becomes very high. However, the high breakdown potential does not help to increase the corrosion fatigue or damage ratio values due to the porous nature of the nitrided layer.

Although the nitrided steel had very high fatigue strength and pitting potential, this did not reflect in its corrosion fatigue and/or damage ratio improvement because of its surface roughness and the porous nature of the nitrided layer.

Under severely aggressive conditions, such as those experienced in the chemical industry, there has been extensive use of stainless steels in order to reduce corrosion losses. The successful industrial use of stainless steels led to requests for information on the corrosion resistance of stainless steels and similar alloys in sea‐water. This paper was awarded a prize in the Essay competition organised by the Corrosion Group of the Society of Chemical Industry, 1959.

This paper aims to study the effect of small ruthenium additions through laser surface alloying of 304L stainless steel on the corrosion resistance when exposed to a 1 M sulphuric acid solution at 25°C.

In this study, the characteristics of laser-alloyed surface layers enriched with low concentrations of ruthenium, less than 0.3 Wt.%, were evaluated. Samples were manufactured by performing laser surface alloying on a 304L stainless steel and using a 304 stainless steel powder enriched with ruthenium. The welded surfaces were cross-sectioned and the microstructure and chemical composition were analysed; in addition, the depth of penetration was determined. The corrosion characteristics of these surface welds were investigated through electrochemical analysis such as open circuit potential measurements and potentiodynamic scans.

It was found that with the addition of ruthenium levels of more than 0.2 Wt.%, the corrosion characteristics when exposed to 1 M sulphuric acid improved in the enriched welded zone.

This study investigated the improvement of the surface layer of the 304L stainless steel because of the cost involved when ruthenium is alloyed in the bulk and showed that an improved corrosion resistance can be achieved in sulphuric acid at room temperature.

The hardness of the laser alloying was not significantly affected by the ruthenium, but more by the laser parameters.

This paper considers the improvement of 304L stainless steel through laser alloying with ruthenium.

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.

The commercial stainless steels have been used extensively in the biomedicine application and their electrochemical behaviour in the simulated body fluid (SBF) are not uncovered obviously. In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys (x = 4, 8, 10 and 14) has been studied. This study aims to evaluate the rate of corrosion and corrosion resistance of some Fe–Cr–Ni alloys in SBF at 37°C.

In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys has been studied using open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization in the SBF at 37°C and pH 7.4 for a week. Also, the surface morphology of the four alloys was investigated using scanning electron microscopy, elemental composition was obtained via energy dispersive spectroscopy and the crystal lattice structure of Fe–17Cr–xNi alloys was obtained using X-ray diffraction technique. The chemical structure of the protective oxide film has been examined by X-ray photoelectron spectroscopy (XPS) and metals ions released into the solution have been detected after different immersion time using atomic absorption spectroscopy.

The results revealed that the increase of the Ni content leads to the formation of the stable protective film on the alloys such as the Fe–17Cr–10Ni and Fe–17Cr–14Ni alloys which possess solid solution properties. The Fe–17Cr–14Ni alloy displayed highest resistance of corrosion, notable resistance for localized corrosion and the low corrosion rate in SBF because of the formation of a homogenously protective oxide film on the surface. The XPS analysis showed that the elemental Fe, Cr and Ni react with the electrolyte medium and the passive film is mainly composed of Cr₂O₃ with some amounts of Fe(II) hydroxide at pH 7.4.

This work includes important investigation to use commercial stainless steel alloys for biomedical application.

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.

A very wide variety of alloy types are available for selection to combat the potential corrosion problems posed in a diverse range of industries. Although in today's climate cost reduction is an important goal, the price of unexpected failure of equipment is often measured as risk to human life, and materials selection must always be given a prime place in design, engineering and construction. Material selection should not be based simply on low installed cost of equipment — the need to maintain safety standards and effective long‐term utilization of a production asset, with minimum costly maintenance and downtime, mandate the selection of materials which can be justified on the basis of life‐cycle cost and risk analysis. The material chosen should provide the lowest cost viable, and if possible, “fit and forget” solution. In the Offshore Oil and Gas industry in the North Sea the solution adopted would need to address the CRINE cost reduction strategy.