Effect of Mo and Mn additions on the corrosion behaviour of AISI 304 and 316 stainless steels in H2SO4

Pardo, Á.; Merino, M.C.; Coy, A.E.; Viejo, F.; Arrabal, R.; Matykina, E.

doi:10.1016/j.corsci.2007.11.004

Cited by 241 publications

(96 citation statements)

References 38 publications

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“…A traditional method to enhance the corrosion resistance of this kind of steels in sulfuric acid solutions involves alloying with 2-3% Mo (up to 5-6% in some cases). The enhancement of corrosion resistance of these steels by molybdenum is attributed to preservation of the passive state in dilute acid solutions and a decrease in its dissolution rate in the active state [2,3]. Nickel-chromium steels can be passivated in H 2 SO 4 by adding an oxidant (e.g., HNO 3 ) to the solution.…”

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confidence: 99%

Protection of nickel-chromium steel in sulfuric acid solution by a substituted triazole

Avdeev¹,

Kuznetsov²,

Tyurina³

et al. 2015

Int. J. Corros. Scale Inhib.

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The corrosion of 12Kh18N10T nickel-chromium steel in 2.0 М H 2 SO 4 (t = 20-100°C) was studied using mass loss, potentiometric, and polarization methods. It was shown that the corrosion resistance of this material in H 2 SO 4 solutions is low, particularly at temperatures close to 100°C. Efficient steel protection in sulfuric acid solutions can be achieved using mixtures of IFKhAN-92 (a triazole derivative) with KI (molar ratio of the components 1:1), KBr (1:9), or KCNS (4:1) as corrosion inhibitors. Of the IFKhAN-92 formulations studied, the highest corrosion inhibition coefficients are provided by the equimolar mixture with KI, despite an antagonism in the action of its components. Decreasing the concentration of this formulation to 0.005-0.025 mM (depending on temperature) does not considerably decrease the protective effect. Mixed inhibitors based on the substituted triazole protect the metal in the acid solution for at least 8 h. The presence of the inhibitors being studied in the solution considerably increases the contribution of diffusion control to the corrosion process, as indicated by a significant decrease in the activation energy from 60  1 to 35  2 kJ/mol in the presence of these compounds. Steel corrosion occurs in the active dissolution region both in background and inhibited acid solutions. A correlation was noted between the free corrosion potential of steel (E cor ) in an acid solution containing an inhibitor and the protective effect of the latter (): the higher the  value of the inhibitor, the more positive the potential of steel. The corrosion inhibition of stainless 12Kh18N10T steel in H 2 SO 4 solutions by formulations based on IFKhAN-92 results from strong hindrance of electrode reactions on the metal by these compounds in a broad temperature range (up to 100С). The strongest inhibition of electrode reactions on stainless steel is provided by the IFKhAN-92+KI mixture. As a result, it has the maximum efficiency in suppression of metal corrosion. A considerable effect on the characteristics of electrode reactions on stainless steel in background and inhibited acid solutions results from selective dissolution of metal surface components.

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confidence: 99%

Protection of nickel-chromium steel in sulfuric acid solution by a substituted triazole

Avdeev¹,

Kuznetsov²,

Tyurina³

et al. 2015

Int. J. Corros. Scale Inhib.

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“…En aquellas muestras donde el contenido de Mo es mayor, C y F, se advertiría que el aumento de corriente es mayor, esto podría deberse a que más allá de que el Mo dentro de la región pasiva contribuye beneficiosamente a la misma, cuando llegamos a la región transpasiva la cantidad de Cr(VI) liberado de las aleaciones aumenta con la adición de Mo [11], si bien la presencia y naturaleza de Mo en la película pasiva es aún profundamente debatido y, por lo tanto, la explicación para el efecto de Mo en la resistencia a la corrosión general de aceros inoxidables es, por el momento, un tema de discusión [12].…”

Section: Probeta C Siunclassified

Pasividad en solución de fosfato de aceros inoxidables solidificados unidireccionalmente

et al. 2015

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RESUMENLa pasividad de los aceros inoxidables es atribuida a la formación de una película protectora, conformada por óxidos, sobre la superficie del metal. Esta película posee propiedades semiconductoras y está relacionada con múltiples factores que la hacen de importancia para la comprensión de los fenómenos de corrosión. En este trabajo se estudia la película pasiva formada en aceros inoxidables solidificados unidireccionalmente, Fe18Cr-10Ni-2Mo-0,08C (muestra A), Fe-18Cr-14Ni-8Mo-0,03C (muestra C) y Fe-18Cr-10Ni-8Mo-0,08C (muestra F), para determinar la influencia de la variación de la estructura (equiaxial, columnar y con transición de columnar a equiaxial-TCE) en la resistencia a la corrosión, así como investigar la relación entre la resistencia a la corrosión y el espaciamiento dendrítico secundario del material. Para ello se emplean técnicas potenciodinámicas y galvanostáticas, análisis de MottSchottky y espectroscopía de impedancia electroquímica que se realizaron en solución de Na 2 HPO 4 0,5 M (pH 9,2).Las curvas potenciodinámicas indican una región pasiva y un máximo de corriente en la región transpasiva. Las medidas galvanostáticas realizadas sobre películas pasivas formadas previamente indican dos amesetamientos de potencial, debido al óxido de Cr y óxido de Fe, del cual surgen dos tiempos de transición. El mayor espesor de óxido de hierro se encuentra en las estructuras equiaxial de la muestra F, que posee el menor espaciamiento dendrítico respecto de los otras dos muestras teniendo en cuenta la misma estructura. El análisis de Mott Schottky muestra que la película pasiva se comporta como un semiconductor tipo n en el rango de potenciales de -0,45 V a 0 V, con una densidad de donores que varía de acuerdo a la composición del acero inoxidable. También se observa que la densidad de donores varía de acuerdo al tipo de estructura para un mismo material.Palabras Clave: aceros inoxidables, película pasiva, Mott Schottky, resistencia a la corrosión. ABSTRACTPassivity of the stainless steel is attributed to the development of a protector film, formed by oxides on the metal surface. This film has semiconductor properties, and it is important for the understanding of corrosion phenomena.The objective of this work is to study the passive films formed in stainless steels samples solidified unidirectionally. The composition of the alloying elements in the samples are Fe-18Cr-10Ni-2Mo-0,08C (sample A), Fe-18Cr-14Ni-8Mo-0,03C (sample C) y Fe-18Cr-10Ni-8Mo-0,08C (sample F), and determine the influence of the structure (equiaxed, columnar and columnar-to-equiaxed transition, CET) in the corrosion resistance, as well as investigate the relationship between the corrosion resistance and the size of the secondary dendritic arm spacing. For this are used potentiodynamic and galvanostatic techniques, Mott Schottky analysis and electrochemical impedance spectroscopy.The measurements were performed in Na 2 HPO 4 0,5 M (pH = 9,2), at room temperature (25ºC).Potentiodynamic measurements indicate a passive region and a maximu...

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“…This category of stainless steels is easily weldable and formable with sufficient corrosion resistance for general purpose applications in mild corrosive environments due to the formation of a passive protective film on the surface of the steels. The passive film consists of the chemical combination of iron and chromium oxy-hydroxide layer, and water containingcompounds at the metal/solution interface [2]. Localized dissolution of the passive film is one of the major causes of pitting corrosion failure of these steels during application.…”

Section: Introductionmentioning

confidence: 99%

Pitting Corrosion Resistance and Inhibition of Lean Austenitic Stainless Steel Alloys

Loto¹

2017

Austenitic Stainless Steels - New Aspects

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The pitting corrosion behavior of 301, 304 and 316 austenitic stainless steels in 2M H 2 SO 4 at 0-1.5% NaCl concentrations was investigated through potentiodynamic polarization and optical microscopy analysis. Electrochemical analysis of the pitting corrosion inhibition and surface protection properties of rosemary oil and aniline on the stainless was also performed. The corrosion rate, pitting potential, passivation potential, metastable pitting potential and surface morphology of both steels where significantly altered by changes in chloride concentration, differences in alloy composition and metallurgical properties of the steels. 316 steel had the lowest corrosion rate and highest pitting corrosion resistance followed by 301 steel. The surface morphology of 316 steel was slightly altered at 1.5% NaCl concentration while 301 steel appears to etch with grain boundaries appearing at higher chloride concentration. 304 steel showed no resistance to pitting after 0% NaCl coupled with relatively significant increase in corrosion rate values. Its surface morphology showed the presence of corrosion pits with respect to chloride and inhibitor concentration. Rosemary oil and aniline significantly reduced the corrosion rates values of the stainless steels and with consequent increase in their pitting corrosion resistance; however the compounds had no positive influence on the pitting corrosion behavior of 304 steel.

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Effect of Mo and Mn additions on the corrosion behaviour of AISI 304 and 316 stainless steels in H2SO4

Cited by 241 publications

References 38 publications

Protection of nickel-chromium steel in sulfuric acid solution by a substituted triazole

Protection of nickel-chromium steel in sulfuric acid solution by a substituted triazole

Pasividad en solución de fosfato de aceros inoxidables solidificados unidireccionalmente

Pitting Corrosion Resistance and Inhibition of Lean Austenitic Stainless Steel Alloys

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