Effect of mechanical stress on electrochemical corrosion of X65 carbon steel in CO2 saturated brine

2020 ◽  
Vol 62 (8) ◽  
pp. 803-808
Author(s):  
Wei Yan

Abstract Applied mechanical stress could accelerate the chemical or electrochemical process of metal corrosion in weak acid solution. Series of experimental tests were conducted in this research. The results show that there is no obvious correlation between OCP (open circuit potential) values and applied stresses. However, The LPR (linear polarization resistance)corrosion rate increased intensively under the applied stress of 400 MPa. Correspondingly, the EIS (electrochemical impedance spectroscopy) Nyquist diagrams show that all of the plots contain a semicircle over the whole frequency range and the semicircle size decreased with increasing applied stress. The real-time corrosion current square waves triggered by the mechanical stress were successfully monitored by using the potentiostatic method in CO2 saturated brine under 200 mv (above OCP), flow and lower pH condition. This result is significant for many research fields, such as petrochemistry, aerospace and nuclear industries, which suffer weak acid corrosive environment.

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 91 ◽  
Author(s):  
Bi-Sheng Huang ◽  
Guan-Hui Lai ◽  
Ta-I Yang ◽  
Mei-Hui Tsai ◽  
Yi-Chen Chou

A novel aniline tetramer (AT) capped electroactive imide oligomer (EIO) for metal corrosion protection was successfully synthesized in this study. The chemical structure of the EIO was characterized by liquid chromatography-mass spectrometry and Fourier-transform infrared spectroscopy. Furthermore, the redox behavior of EIO was identified using electrochemical cyclic voltammetry studies. An EIO coated on a cold-rolled steel (CRS) electrode was found to possess superior corrosion resistance to polyimide (PI) on a series of electrochemical corrosion measurements in 3.5 wt.% NaCl solution over an extended period (30 days). The mechanism for the advanced corrosion protection of the PI coating on the CRS electrode could be attributed to the redox catalytic capabilities of the AT units present in the EIO. These capabilities may induce the formation of passive metal oxide layers on the CRS electrode. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to analyze the surface condition of the CRS after the corrosion test. EIO- and PI-coated electrodes were identified by a series of electrochemical measurements, including corrosion potential (Ecorr), polarization resistance (Rp), and corrosion current (Icorr) measurements, along with electrochemical impedance spectroscopy (EIS).


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1317
Author(s):  
Hongmei Zhang ◽  
Ling Yan ◽  
Yangyang Zhu ◽  
Fangfang Ai ◽  
Hongnan Li ◽  
...  

In this paper, electrochemical corrosion tests and full immersion corrosion experiments were conducted in seawater at room temperature to investigate the electrochemical corrosion behavior and the corrosion mechanism of high-strength EH47. The polarization curve, EIS (electrochemical impedance spectroscopy), SEM (scanning electron microscope), and EDS analyses were employed to analyze the results of the electrochemical corrosion process. The electrochemical corrosion experiments showed that the open circuit potential of EH47 decreases and then increases with an increase in total immersion time, with the minimum value obtained at 28 days. With an increase in immersion time, the corrosion current density (Icorr) of EH47 steel first decreases and then increases, with the minimum at about 28 days. This 28-day sample also showed the maximum capacitance arc radius, the maximum impedance and the minimum corrosion rate. In the seawater immersion test in the laboratory, the corrosion mechanism of EH47 steel in the initial stage of corrosion is mainly pitting corrosion, accompanied by a small amount of crevice corrosion with increased corrosion time. The corrosion products of EH47 steel after immersion in seawater for 30 days are mainly composed of FeOOH, Fe3O4 and Fe2O3.


Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 454 ◽  
Author(s):  
Arman Dastpak ◽  
Kirsi Yliniemi ◽  
Mariana de Oliveira Monteiro ◽  
Sarah Höhn ◽  
Sannakaisa Virtanen ◽  
...  

In this study, a waste of biorefinery—lignin—is investigated as an anticorrosion coating on stainless steel. Corrosion behavior of two lignin types (hardwood beech and softwood spruce) was studied by electrochemical measurements (linear sweep voltammetry, open circuit potential, potentiostatic polarization, cyclic potentiodynamic polarization, and electrochemical impedance measurements) during exposure to simulated body fluid (SBF) or phosphate buffer (PBS). Results from linear sweep voltammetry of lignin-coated samples, in particular, demonstrated a reduction in corrosion current density between 1 and 3 orders of magnitude cf. blank stainless steel. Furthermore, results from cross cut adhesion tests on lignin-coated samples demonstrated that the best possible adhesion (grade 0) of ISO 2409 standard was achieved for the investigated novel coatings. Such findings suggest that lignin materials could transform the field of organic coatings towards more sustainable alternatives by replacing non-renewable polymer coatings.


2021 ◽  
Vol 41 (3) ◽  
Author(s):  
Sunčana Smokvina Hanza ◽  
Ladislav Vrsalović ◽  
Lovro Štic ◽  
Lovro Liverić

This paper presents results of the corrosion investigations of specimens made from finished parts for the automotive industry, produced by high-pressure die casting and gravity die casting process of six Al-Si alloys (40000 series). Open circuit potential and potentiodynamic polarization measurements have been performed using a potentiostat with three-electrode set-up in 0.6 M NaCl naturally aerated solution. Microstructural characterization before and after electrochemical investigations has been carried out with optical microscope to establish the connection between microstructure and corrosion parameters of investigated alloys and to analyze and record surface changes of each sample due to electrochemical corrosion. All alloys show good corrosion resistance, which manifests with low values of corrosion rates, calculated from the corrosion current densities obtained from potentiodynamic polarization measurements. Differences in electrochemical behavior appear due to the distinctions in their chemical composition and microstructure. The type of casting process does not affect electrochemical behavior of Al-Si alloys.


Author(s):  
Vishnu R. ◽  
Jiten Das ◽  
S. B. Arya ◽  
Manish Roy

Recently, ZrN has been attracting interest for its excellent corrosion resistance, biocompatibility, high hardness, good lubricity and ductility. Although tribological study of ZrN coating has been carried out extensively, investigation related to corrosion of ZrN film is limited. In view of this and in view of possible applications of ZrN film in several engineering components, the present investigation has been undertaken to evaluate the corrosion response of ZrN film in seawater solution, Hank's solution, 0.5M H2SO4solution and 0.5M HCl solutions. Towards that purpose, potentiostatic, open circuit potential and potentiodynamic study of ZrN film deposited on plain carbon steel has been carried out in all these solutions. Results indicate that stable protective film is formed on the surface of ZrN coating in all these solution except 0.5M H2SO4 solution. The formation of protective film on ZrN coating is fastest in sea water solution and it is slowest in the Cl¯ ions containing media, 0.5 M HCl. The corrosion current is highest for 0.5M H2SO4 acid solution and least for Hank's solution.


Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1325 ◽  
Author(s):  
Jian-Bao Wang ◽  
Guang-Chun Xiao ◽  
Wei Zhao ◽  
Bing-Rong Zhang ◽  
Wei-Feng Rao

The microstructure and corrosion resistance in H2S environments for various zones of X80 pipeline steel submerged arc welded joints were studied. The main microstructures in the base metal (BM), welded metal (WM), coarse-grained heat-affected zone (CGHAZ), and fine-grained heat-affected zone (FGHAZ) were mainly polygonal ferrite and granular bainite; acicular ferrite with fine grains; granular bainite, ferrite, and martensite/austenite constituents, respectively. The corrosion behavior differences resulted from the microstructure gradients. The results of the micro-morphologies of the corrosion product films and the electrochemical corrosion characteristics in H2S environments, including open circuit potential and electrochemical impedance spectroscopy, showed that the order of corrosion resistance was FGHAZ > BM > WM > CGHAZ.


Author(s):  
YeoHeung Yun ◽  
Zhongyun Dong ◽  
Dianer Yang ◽  
Vesselin Shanov ◽  
Zhigang Xu ◽  
...  

Corrosion and cell culture experiments were performed to evaluate magnesium (Mg) as a possible biodegradable implant material. The corrosion current and potential of a Mg disk were measured in different physiological solutions. The corrosion currents in cell culture media were found to be higher than in deionized water, which verifies that corrosion of Mg occurs faster in chloride solution. Weight loss, open-circuit potential, and electrochemical impedance spectroscopy measurements were also performed. The Mg specimens were also characterized using an environmental scanning electron microscope and energy-dispersive x-ray analysis (EDAX). The x-ray analysis showed that in the cell culture media a passive interfacial layer containing oxygen, chloride, phosphate, and potassium formed on the samples. U2OS cells were then co-cultured with a Mg specimen for up to one week. Based on visual observation, cell growth and function were not significantly altered by the presence of the corroding Mg sample. These initial results indicate that Mg may be suitable as a biodegradable implant material. Future work will develop small sensors to investigate interfacial biocompatibility of Mg implants.


2016 ◽  
Vol 835 ◽  
pp. 131-135 ◽  
Author(s):  
Francis Mulimbayan ◽  
Manolo G. Mena

Stainless steel (SS) is one of the most commonly used metallic food contact materials. It may be classified based on its microstructure whether ferritic, austenitic, martensitic, duplex or precipitation hardened. Austenitic SS, among mentioned grades, has the largest contribution to market due to its numerous industrial and domestic applications. In this study, the corrosion behavior of AISI 202 SS – a cheaper grade of stainless steel, in three different solution temperatures of citric acid was investigated using different electrochemical techniques such as open-circuit potential (OCP) measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results were compared to that obtained from conventional AISI 304 SS. OCP, polarization and impedance measurements agreed that AISI 202 SS has comparable resistance to that of AISI 304 SS in citric acid at ambient temperature and at 50 °C. At 70 °C, results of OCP measurements suggest that AISI 304 SS exhibited greater performance as indicated by more positive OCP values in the designated solution. EIS results indicate that the two alloys have identical corrosion resistance even at 70 °C as indicated by their comparable polarization resistance (Rp). The corrosion mechanism in both alloys is charge-transfer controlled as indicated by depressed semi-circular appearance of the generated Nyquist plots. The values of corrosion current densities (icorr) extracted from polarization curves indicate that the initial corrosion rates were higher in AISI 304 than AISI 202 SS suggesting that formation of more protective film may have occurred on the former alloy.


Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 986
Author(s):  
Shenghan Zhang ◽  
Chenhao Sun ◽  
Jie Di ◽  
Yu Tan

Passive films were formed on A508-3 steel (A508-3), 304L stainless steel (304L) and Incoloy 800 (In800) with blank/zinc/zinc–aluminum treatments in air at 300 °C. The electrochemical corrosion behaviors of different metals were investigated through potentiodynamic polarization, electrochemical impedance spectroscopy and the Mott–Schottky technique. The morphology and composition of passive films were analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The zinc–aluminum treatment effectively reduced the corrosion current and increased the impedance of A508-3 and 304L, but had a weak effect on In800. The zinc–aluminum treatment reduced the carrier concentration of A508-3 and changed the semiconductor property of 304L and In800. The order of zinc–aluminum treatment for improving the corrosion resistance of three metals was: A508-3 > 304L > In800. In addition, the zinc–aluminum treatment enhanced the density and smoothness of passive films. According to the composition analysis, spinel ZnAl2O4 was formed on three metals; however, the amount of spinel varied with the content of nickel and chromium in different metals, which affected the results of using this technology.


Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 724 ◽  
Author(s):  
Zhang ◽  
Hong ◽  
Lin ◽  
Zheng

The corrosion behavior of unsealed and sealed high-velocity oxygen-fuel (HVOF)-sprayed nanostructured WC-CoCr cermet coatings under different corrosive environments was investigated using scanning electron microscopy (SEM), open circuit potential (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Ultrasonic excitation sealing with aluminum phosphate was performed in an external ultrasonic bath with the frequency of 40 kHz at atmospheric pressure and room temperature. SEM micrographs revealed that the exposed area of the coating was effectively reduced by the coverage of aluminum phosphate sealant on the majority of pores. Electrochemical measurements demonstrated that the sealant with the help of ultrasonic energy could shift the corrosion potential to a more noble direction, reduce the corrosion current density, increase the resistance of charge transfer, and effectively improve the corrosion resistance of the coating in both 3.5 wt % NaCl and 1 mol·L−1 HCl solutions.


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