Growth of corrosion product film on 12Cr1MoV steel in sulfur-containing sodium aluminate solution

2019 ◽  
Vol 9 (8) ◽  
pp. 914-922 ◽  
Author(s):  
Jingjiu Yuan ◽  
Chaoyi Chen ◽  
Junqi Li ◽  
Bianli Quan ◽  
Linzhu Wang ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Corrosion Product ◽  
Electrochemical Impedance ◽  
Sodium Aluminate ◽  
Aluminate Solution ◽  
Corrosion Product Film ◽  
Sodium Aluminate Solution ◽  
Product Film ◽  
Film Layer ◽  
Sulfur Containing

The growth mechanism of product film on steel surface in sulfur-containing sodium aluminate solution was studied with relevance to processing of high-sulfur bauxite ores in Bayer process. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) were used to study the growth of corrosion product film on 12Cr1MoV steel in sodium aluminate solution containing 5 g/L S2– and 3 g/L S2O2– 3. Results indicated that the corrosion rate gradually decreased with increasing corrosion time (t). The fitted corrosion rate equation was V = 4.365t–0.809. The corrosion resistance was highest after 5 d. The growth evolution of the product film was divided into three stages: film formation, film conversion and film growth. The final corrosion product film comprised an inner film layer mainly composed of Fe3O4 and an outer film layer mainly composed of FeS, FeS2 and Fe2O3.

scholarly journals Initial Corrosion Behavior of 12Cr1MoV Steel in Thiosulfate-Containing Sodium Aluminate Solution

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1283
Author(s):  
Jingjiu Yuan ◽  
Chaoyi Chen ◽  
Junqi Li ◽  
Bianli Quan ◽  
Yuanpei Lan ◽  
...  
Keyword(s):  
Corrosion Product ◽  
Corrosion Behavior ◽  
Corrosion Current ◽  
Sodium Aluminate ◽  
Corrosion Mechanism ◽  
Alumina Production ◽  
Aluminate Solution ◽  
Corrosion Product Film ◽  
Product Film ◽  
Corrosion Pits

When alumina is produced by the Bayer process with high-sulfur bauxite, the sulfur would strongly corrode the 12Cr1MoV steel made heat exchanger. This study investigated the initial corrosion behavior of the 12Cr1MoV steel exposed to a thiosulfate-containing sodium aluminate (TCSA) solution under the evaporation conditions of alumina production. The obtained corrosion rate equation is V = 6.306·t·exp(−0.71). As corrosion progressed, with the corrosion product film growing, the corrosion current density declines slowly, and the corrosion resistance of the steel is increased. At 1–3 days, the corrosion product film consisted of FeO, Fe2O3, and FeOOH. S2O32− lead to corrosion in local areas of the steel and pits appeared. AlO2− is transformed into Al(OH)3 and filled in the corrosion pits. At 4 and 5 days, Fe3O4 is generated in the outermost layer, and Al(OH)3 is shed from the corrosion pits. The corrosion mechanism of 12Cr1MoV steel in a TCSA solution is proposed based on the experimental results.

scholarly journals Corrosion Product Film of a Medium-Mn Steel Exposed to Simulated Marine Splash Zone Environment

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5652
Author(s):  
Xinyong Yan ◽  
Shumei Kang ◽  
Meiling Xu ◽  
Pengyu Li
Keyword(s):  
Corrosion Product ◽  
Electrochemical Impedance ◽  
Corrosion Products ◽  
Splash Zone ◽  
Rust Layer ◽  
Positive Direction ◽  
Corrosion Product Film ◽  
Medium Mn Steel ◽  
Product Film ◽  
Mn Steel

The corrosion behavior of a medium-Mn steel in a simulated marine splash zone was studied by a dry–wet cyclic corrosion experiment and electrochemical experiment. The corrosion products were characterized by corrosion rate calculation, composition detection, morphology observation, element distribution detection, valence analysis, polarization curve, and electrochemical impedance test. The results show that the corrosion products of the sample mainly include γ-FeOOH, FexOy, MnxOy, and a small amount of (Fe,Mn)xOy, and the valence state of iron compounds and manganese compounds in different corrosion stages changed obviously. In the initial corrosion products, Mn is enriched significantly and facilitates the electrochemical reaction of corrosion process. The content of Ni in the inner rust layer is high. The semi-quantitative analysis of the corrosion product elements shows that the atomic concentrations of Cr and Mo increase significantly in later corrosion products, indicating that the dense isolation layer formed by alloy element compounds in the corroded layer is the main factor to improve the protection ability of the rust layer at the end corrosion stage of the sample. With the corrosion durations, the corrosion current density of the sample with the corrosion product film first increases and then decreases, and the corrosion potential first moves negative and then shifts in a positive direction subsequently, indicating that the protective effect of the corrosion product film is gradually significant.

Corrosion control in CO2/H2S-produced water of offshore oil fields

2014 ◽  
Vol 61 (3) ◽  
pp. 166-171 ◽  
Author(s):  
Yuan Lu ◽  
Ying Zhang ◽  
Zhenguo Liu ◽  
Yong Zhang ◽  
Chaoming Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Product ◽  
Produced Water ◽  
Oil Field ◽  
Protective Film ◽  
Organic Amine ◽  
Content Type ◽  
Corrosion Product Film ◽  
Product Film

Purpose – In order to solve the corrosion problems in the South China Sea, the purpose of this paper was to study the main influences of corrosion including temperature, H2S content and corrosion inhibitor content in CO2/H2S oil field-produced water. Design/methodology/approach – The corrosion products formed on the steel surface were observed and analyzed using scanning electron microscope (SEM) and X-ray diffraction (XRD). Findings – The results indicate that temperature significantly influences the corrosion rate, which is a maximum at 70°C. The corrosion rate decreases as H2S content increases which is less than 10 mg/L, but then it increases rapidly. The FeCO3/Fe x S y protective film and a corrosion inhibition also were considered. Research limitations/implications – A mixture containing an imidazoline derivate and an organic amine can enhance the corrosion resistance of the corrosion product film. Practical implications – A mixture containing an imidazoline derivate and an organic amine can enhance the corrosion product film corrosion resistance. Social implications – Imidazoline is one kind of environmentally safe agent which can be used in the ocean. Originality/value – The corrosion can be controlled to a satisfactory extent in the presence of a mixture containing an imidazoline derivate and an organic amine.

scholarly journals Corrosion behavior and electrochemical corrosion of a high manganese steel in simulated marine splash zone

2021 ◽  
Author(s):  
Xinyong Yan ◽  
Ling Yan ◽  
Shumei Kang ◽  
Xiangyu Qi ◽  
Meiling Xu ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Corrosion Product ◽  
Corrosion Products ◽  
Manganese Steel ◽  
Splash Zone ◽  
High Manganese ◽  
Rust Layer ◽  
High Manganese Steel ◽  
Corrosion Product Film ◽  
Product Film

Abstract The corrosion behavior of a high manganese steel in simulated marine splash zone environment was studied by dry-wet cyclic corrosion experiment and electrochemical experiment. Corrosion kinetics, composition, surface morphology, cross-section morphology, element distribution, valence state, polarization curve and electrochemical impedance spectroscopy were analyzed with the aim of characterizing the characteristics of corrosion product films. The results show that in chloride-containing environment, in the initial corrosion products, Mn oxides with porous structure lead to higher corrosion rate. As corrosion extends, the formation of alloy element oxides in corrosion products changes the corrosion properties of rust layers at different stages. Mo oxides form a stable passivation film, which reduces the influence of chloride ion on corrosion. Ni oxides in the inner rust layer facilitate the transformation of goethite, and Cr oxides in the outer rust layer increase the densification of the rust layer. The stability and compactness of Fe3O4, α-FeOOH and FeCr2O4 in the later corrosion products inhibit the corrosion action of manganese iron oxides and slow down the corrosion rate. With the corrosion durations, the corrosion current density of the sample with the corrosion product film first increases and then decreases, and the corrosion potential first moves negative and then shifts in a positive direction subsequently, indicating that the protective effect of the corrosion product film is gradually significant.

scholarly journals Effect of process parameters on the morphology and adsorption properties of nanocrystalline boehmite

2014 ◽  
Vol 68 (3) ◽  
pp. 357-362
Author(s):  
Zoran Obrenovic ◽  
Ljubica Nikolic ◽  
Radislav Filipovic ◽  
Marija Milanovic ◽  
Ivan Stijepovic
Keyword(s):  
Ph Value ◽  
High Surface ◽  
High Surface Area ◽  
Average Crystallite Size ◽  
Sodium Aluminate ◽  
Adsorption Properties ◽  
Transition Alumina ◽  
Aluminate Solution ◽  
Bayer Liquor ◽  
Sodium Aluminate Solution

In the last decade, exploration of transition alumina phases with good adsorption properties has attracted a great research interest from both a fundamental and a practical point of view. The transition phases of alumina are metastable polymorphs of aluminum oxide formed through the thermal dehydration of aluminum trihydroxide and aluminum oxyhydroxide. Powder X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and low-temperature nitrogen absorption studies were employed to trace the formation of the transition phases of alumina. In this work transition alumina powders were synthesized starting from sodium aluminate solution prepared from Bayer liquor. The neutralization of sodium aluminate solution was performed with the use of sulphuric acid, while glucose was added in the starting solution. In this way, the single phase nanocrystalline boehmite was obtained. As-synthesized boehmite powders have high surface area (above 360 m2/g) and the average crystallite size less than 5 nm. The results showed that the properties of the powders (structure, morphology) are strongly influenced by the initial pH value of sodium aluminate solution, as well as by the duration of neutralization step.

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