Research on Corrosion Characteristics of Mild Steel in Sea Water at Weihai

2012 ◽  
Vol 229-231 ◽  
pp. 31-34
Author(s):  
Yan Gang Wang ◽  
Xing Hua Tong ◽  
Yong Jiang ◽  
Yong Liu ◽  
Lin Sen Zhu

The corrosion characteristics of mild steel in real sea water are investigated by electrochemical test in this paper. Polarization curves and electrochemical impedance spectroscopy (EIS) are got by electrochemical workstation. From polarization curves, it is found that the corrosion rate rises at the initial period, and it becomes the highest on the 3rd day, then drops, and it tends to be stable after about 15 days, which is confirmed by EIS. In addition, the experiments also show that the corrosion layer can suppress the corrosion process. The electrochemical corrosiveness of the mild steel is analyzed in this study, and it lays a foundation for anticorrosion technology research.

2012 ◽  
Vol 591-593 ◽  
pp. 1046-1049
Author(s):  
Yong Liu ◽  
Xing Hua Tong ◽  
Bao Guo Li ◽  
Yan Gang Wang ◽  
Lin Sen Zhu

In order to study the corrosion characteristics of 16Mn and Q235B steel in natural seawater, the indoor contrast corrosion experiments are carried out in seawater by electrochemical method. Tafel polarization curves and electrochemical impedance spectroscopy (EIS) techniques are employed to investigate the corrosion electrochemical behavior of 16Mn and Q235B steel, which are acquired by electrochemical workstation. The results of polarization curves and EIS reveal the respective corrosion rules of 16Mn and Q235B steel in natural seawater. At last, the different influence of rust layer on the corrosion process of 16Mn and Q235B steel is analyzed contrastively.


2012 ◽  
Vol 229-231 ◽  
pp. 40-43
Author(s):  
Yong Liu ◽  
Xing Hua Tong ◽  
Bao Guo Li ◽  
Yan Gang Wang ◽  
Lin Sen Zhu

In order to study the corrosion behavior of Q235B steel in seawater at Weihai, the indoor simulated and accelerated corrosion test is carried out by adding H2O2 in seawater. Tafel polarization curves and electrochemical impedance spectroscopy (EIS) techniques are employed to investigate the corrosion electrochemical behavior of Q235B steel. Polarization curves and EIS are acquired by electrochemical workstation. From polarization curves, it is found that the corrosion rate rises rapidly during the initial period, and it becomes highest on the 3rd day, then drops, and tends to be stable after about 15 days. After that, the corrosion rate reduces slowly due to the covering effect of corrosion products, and then the conclusion is confirmed by EIS analysis. Analytical results indicate that the rust layer plays a positive role of hindering the corrosion process.


2012 ◽  
Vol 591-593 ◽  
pp. 1030-1033
Author(s):  
Yan Gang Wang ◽  
Xing Hua Tong ◽  
Yong Jiang ◽  
Yong Liu ◽  
Lin Sen Zhu

The corrosion characteristics of various steels used by ocean wave energy equipment in sea water are investigated by electrochemical tests in this paper. The electrochemical experiments are carried out to research the corrosion rules of Q235, 20# steel, 16Mn and X42 through contrast experiments. Polarization curves and electrochemical impedance spectroscopy (EIS) are got by electrochemical workstation. Corrosion rates and corrosion potentials are analyzed from the polarization curves, and corrosion rules are founded. In addition, EIS is analyzed, and the analysis results are consistent with the results of polarization curves.


2017 ◽  
Vol 24 (6) ◽  
pp. 825-832 ◽  
Author(s):  
Murat Ates

AbstractMethylcarbazole (MCz) and its nanocomposites with Montmorillonite nanoclay and Zn nanoparticles were chemically synthesized on a stainless steel (SS304) electrode. The modified electrode was characterized by optical microscope, scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), Fourier-transform infrared spectroscopy-attenuated transmission reflectance (FTIR-ATR), four-point probe, and electrochemical impedance spectroscopy (EIS) analysis. The synthesized stainless steel/poly(methylcarbazole) (SS/P(MCz)), stainless steel/poly(methylcarbazole)/nanoclay (SS/P(MCz)/nanoclay), and stainless steel/poly(methylcarbazole)/nanoZn (SS/P(MCz)/nanoZn) were studied by potentiodynamic polarization curves. The protective behavior of these coatings in 3.5% NaCl as the corrosion medium was investigated using Tafel polarization curves, as well as electrochemical impedance spectroscopy. The corrosion protection parameters were also supported by EIS and an equivalent circuit model of Rs(Qc(Rc(QpRct))). The corrosion current of the SS/P(MCz)/nanoclay samples was found to be much lower (icorr=0.010 μA×cm-2) than that of SS/P(MCz)/nanoZn (icorr=0.031 μA×cm-2) and pure SS/P(MCz) samples. These results reveal that chemically synthesized SS/P(MCz), SS/P(MCz)/nanoclay, and SS/P(MCz)/nanoZn nanocomposite film coating have high corrosion protection efficiency (PE=99.56%, 99.89%, and 99.67%, respectively). Thus, based on the study findings, we posit that nanoclay and Zn nanoparticles possess favorable barrier properties, which can be employed in order to achieve improvements in chemical corrosion protection through P(MCz) coating.


2011 ◽  
Vol 695 ◽  
pp. 425-428
Author(s):  
Duo Wang ◽  
De Ning Zou ◽  
Chang Bin Tang ◽  
Kun Wu ◽  
Huan Liu

Supermartensitic stainless steel grades are widely used in oil and gas industries to substitute duplex and super duplex stainless steels these years. In this paper the corrosion behavior of supermartensitic stainless steels with different chemical compositions, S-165 and HP, was investigated in Cl-environment. All the samples were treated by quenching at 1000 °C followed by tempering at 630 °C for 2h. After heat treatment, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) were determined on both kinds of samples. Polarization curves shows that the metastable pitting nucleuses were formed in passive area and the Cr content is the most important factor leading to the differences of pitting potential. The potentiodynamic polarization curves were conducted at various NaCl contents (5000, 15000 and 35000 ppm) and emphasized the need to account for the Cl-sensitivity of samples under corrosion environment. The results show that, the pitting potential decrease with the increase of chloride contents. The behavior of passive film was analyzed by electrochemical impedance spectroscopy.


Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2611
Author(s):  
Esther Udabe ◽  
Anthony Sommers ◽  
Maria Forsyth ◽  
David Mecerreyes

Chromate free corrosion inhibitors are searched for to mitigate the economic loss caused by mid-steel corrosion. Here, we show metal-free organic inhibitors having free coumarate anions that can be used either as direct corrosion inhibitors or incorporated into a polymer coating obtained by UV-curing. Four different ionic liquid monomers and polymer coatings with hexoxycoumarate anion and different polymerizable counter cations were investigated. Potentiodynamic polarization, electrochemical impedance spectroscopy, and surface analyses have verified their corrosion inhibition performance on a mild steel AS1020 surface. In the case of the coumarate ionic liquid monomers, the most promising inhibitor is the one coupled with the ammonium cation, showing an inhibition efficiency of 99.1% in solution followed by the imidazolium, pyridinium, and anilinium. Next, the ionic liquid monomers were covalently integrated into an acrylic polymer coating by UV-photopolymerization. In this case, the barrier effect of the polymer coating is combined with the corrosion inhibitor effect of the pendant coumarate anion. Here, the best polymer coatings are those containing 20% imidazolium and pyridinium cations, presenting a greater impedance in the EIS (Electrochemical Impedance Spectroscopy) measurements and less evidence of corrosion in the scribe tests. This article shows that the cationic moiety of coumarate based ionic liquids and poly(ionic liquid)s has a significant effect on their excellent corrosion inhibition properties for a mild steel surface exposed to aqueous chloride solutions.


2017 ◽  
Vol 744 ◽  
pp. 380-384
Author(s):  
Hui Tong ◽  
Wen Li Han ◽  
Zhong Ping Xu ◽  
Yan Jun Zhang ◽  
Zhu Lin ◽  
...  

Electrochemical impedance spectroscopy (EIS) is a technology of nondestructive electrochemical testing. In this paper, EIS is applied to study the corrosion processes of Al-Mg coatings. In the initial 24 h of immersion in 3.5% NaCl solution, passive films of Al-Mg coatings dissolve quickly. As time passed, corrosion products increase on surface gradually, which can inhibit corrosion. After 480h of immersion, corrosion products fully cover on Al-Mg coatings’ surface. The EIS of different corrosion processes are fitted by three equivalent circuits corresponding to the three corrosion processes. In the test of open circuit potentials (OCP), OCP is instable in the initial 24 h of immersion. As immersion time goes by, OCP tends to stabilization at about -0.90 V. Measurements of scanning electron microscope (SEM) confirm the conclusions of electrochemical measurements.


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