Inhibiting the corrosion of stainless steel in phosphoric acid

Filimonov, E. V.; Щербаков, А. И.

doi:10.1007/bf02758411

Cited by 9 publications

(21 citation statements)

References 1 publication

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“…24 Nitrate ions can be reduced electrochemically from very dilute solutions with a sufficiently high rate in the presence of cuprous ions. 62 This process enhances the passivation ability of nitrates in acidic media − higher concentrations would otherwise be required for reliable passivation. 62 Ce(SO 4 ) 2 , as a Ce(IV) salt, proved ineffective as a corrosion inhibitor due to its low solubility and to the low pH of its aqueous solution, as well as to the fact that the formation of precipitates requires the formation of Ce(III) ions.…”

Section: Resultsmentioning

confidence: 99%

Corrosion Inhibition of Pure Aluminium and Alloys AA2024-T3 and AA7075-T6 by Cerium(III) and Cerium(IV) Salts

Rodič

Milošev

2015

J. Electrochem. Soc.

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The corrosion protection of pure aluminium and its alloys AA2024-T3 and AA7075-T6 has been studied in 0.1 M NaCl with and without the addition of Ce(III) chloride, Ce(III) nitrate, Ce(III) acetate and Ce(IV) sulfate. The study of Ce(III) acetate has been scarce but is here shown to be the most effective of the cerium salts studied, especially for AA7075-T6. The inhibition effectiveness of cerium salts is: Ce(III) acetate > Ce(III) chloride > Ce(III) nitrate for the metals studied. Ce(IV) sulfate does not inhibit corrosion. Electrochemical potentiodynamic measurements were used to investigate the mechanism of inhibition by cerium salts. Immersion tests in 0.1 M NaCl, with and without the addition of Ce(III) chloride and Ce(III) acetate, were performed to determine the effects of the inhibitors on the extent of corrosion damage at the surface of all three metals. For pure aluminium the inhibitory effectiveness was 78.5%, 82.6% and 84.0% in the presence of 3 mM Ce(III) nitrate, chloride and acetate, respectively. Aluminium and its alloys 2024-T3 (AA2024-T3) and 7075-T6 (AA7075-T6) generally have good resistance to corrosion under atmospheric conditions. They are used as construction materials, primarily in aircraft applications, because of their physical characteristics such as rigidity and high strength-to-weight ratio.1,2 The main differences between aluminium and its alloys lie in their mechanical and corrosion properties. Aluminium is cold worked, whereas AA2024-T3 and AA7075-T6 are heat treated and cold worked (T3) or artificially aged (T6). The reason for alloying aluminium is to increase strength by forming intermetallic particles, IMs.

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Section: Resultsmentioning

confidence: 99%

Corrosion Inhibition of Pure Aluminium and Alloys AA2024-T3 and AA7075-T6 by Cerium(III) and Cerium(IV) Salts

Rodič

Milošev

2015

J. Electrochem. Soc.

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“…The very slow rate of corrosion is confirmed by ICP-MS analyses of the dissolved Cu concentration in the microcell, which increases from 1.8 mM after 120 d to 3.2 mM after 363 d. This can be compared to the 70 mM to 90 mM concentrations, accompanied by the copious deposition of corrosion products, observed after 25 This behavior shows that corrosion is inhibited in HNO 3 solutions consistent with literature claims that NO − 3 reduction is difficult to induce on Cu surfaces. 28,30 A number of studies have shown that, depending on the Cu crystal plane, NO − 3 reduction is either completely blocked or proceeds very slowly. 29,52 Based on AFM and enhanced Raman spectroscopy studies, this was attributed to either the chemisorption of NO − 3 or to the formation of Cu 2 O by the extraction of an O atom from adsorbed NO − 3 .…”

Section: Resultsmentioning

confidence: 99%

“…Cu corrosion driven by both NO − 3 and O 2 reduction will lead to the consumption of H + . For each dissolved Cu 2+ species produced by O 2 reduction, 4H + or 2H + will be consumed [26][27][28] regardless of whether the O 2 is fully reduced to H 2 O,…”

Section: Introductionmentioning

confidence: 99%

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The Effects of Cathodic Reagent Concentration and Small Solution Volumes on the Corrosion of Copper in Dilute Nitric Acid Solutions

et al. 2017

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The exposure conditions experienced by copper-coated highlevel nuclear waste containers in a deep geologic repository will evolve with time. An early exposure period involving the gamma irradiation of aerated humid vapor could lead to the formation of nitric acid condensed in limited volumes of water on the container surface. The evolution of the corrosion processes under these conditions have been studied using pH measurements in limited volumes of water containing various concentrations of nitric acid. The extent and morphology of corrosion was examined using scanning electron microscopy on surfaces and on focused ion beam cut cross sections. The composition of corrosion products was determined by energy dispersive x-ray analyses and Raman spectroscopy. In the absence of dissolved oxygen only minor corrosion was observed with the reduction of nitric acid inhibited by the formation of either chemisorbed nitrate and nitrite species or the formation of a thin cuprite (Cu 2 O) layer. When the solution was aerated, both oxygen and nitric acid acted as cathodic reagents. After extensive exposure periods corrosion was stifled by the formation of corrosion product deposits of Cu 2 O, CuO (tenorite), and Cu 2 NO 3 (OH) 3 (rouaite).

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“…Addition of Cu(II) cations obtained by dissolving CuO in H 3 PO 4 , or 3 NO  anions in the form of NaNO 3 is recommended to protect X18H10T chromium-nickel steel in hot H 3 PO 4 solutions (up to 130С). The mechanism of action of these additives that favor the existence of chromium-nickel steel in H 3 PO 4 solutions in the passive state was studied [97,98].…”

Section: N H 3 Po 4 (T = 50c)mentioning

confidence: 99%

Protection of metals in phosphoric acid solutions by corrosion inhibitors. A review

2019

Int. J. Corros. Scale Inhib.

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The article summarizes the literature data and patents on the protection of steels and nonferrous metals in phosphoric acid solutions with various corrosion inhibitors. Some aspects of practical use of H 3 PO 4 solutions, their properties and corrosivity toward various metals are reviewed. It is shown that the overwhelming majority of individual organic and inorganic compounds, as well as composite inhibitors offered for the protection of metals in this medium are of low efficiency due to weak adsorption on metal surfaces. A promising method for the protection of steels in phosphoric acid media involves the use of formulations containing triazole derivatives and sulfur-containing additives. The components of these mixtures form polymolecular protective layers on the metal surface that are highly efficient in slowing down corrosion processes even at temperatures up to 100С. An important property of these protective layers is a strong chemical bond of the inhibitor molecules with the metal surface and with each other inside the layer. Inhibited H 3 PO 4 solutions resistant to the accumulation of corrosion stimulators-Fe(III) saltsmay become a new and promising field of use for this acid. The bibliographic list includes 170 sources.

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Inhibiting the corrosion of stainless steel in phosphoric acid

Cited by 9 publications

References 1 publication

Corrosion Inhibition of Pure Aluminium and Alloys AA2024-T3 and AA7075-T6 by Cerium(III) and Cerium(IV) Salts

Corrosion Inhibition of Pure Aluminium and Alloys AA2024-T3 and AA7075-T6 by Cerium(III) and Cerium(IV) Salts

The Effects of Cathodic Reagent Concentration and Small Solution Volumes on the Corrosion of Copper in Dilute Nitric Acid Solutions

Protection of metals in phosphoric acid solutions by corrosion inhibitors. A review

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