EIS Study of Corrosion Behavior of Hot-Dip Galvanized Steel in 5% NaCl Aqueous Solution

2011 ◽  
Vol 335-336 ◽  
pp. 779-782
Author(s):  
Shi Quan He ◽  
Hui Zhong

Corrosion behaviour of hot-dip galvanized steel in 5% NaCl aqueous solution was studied by electrochemical impedance spectrum (EIS) technique. The results revealed that corrosion behaviour of hot-dip galvanized steel has a great relationship with immersion time. With the increase of immersion time, corrosion products are constantly changing, and the impedance of corrosion products are different. Parameters fitted by equivalent circuit show that the impedance of corrosion products increased at first, then decreased.

2011 ◽  
Vol 284-286 ◽  
pp. 2094-2101
Author(s):  
Si Xian Rao ◽  
Li Bing Zhang ◽  
Wei Wei ◽  
Zi Wei Pan

Effects of CDI on corrosion behavior of AA2024-T3 in 3% NaCl aqueous solution are investigated through electrochemical techniques. the results show that CDI could lead to negative shift of free potential, breakdown potential and protection potential of AA2024-T3 and enhance the sensitivity of AA2024-T3 to pitting. The electrochemical impedance spectrum results show that Rp decreased significantly under applied stress and Rp can be taken as the indicator to evaluate the effect of CDI. Different strain rate could influence the effect of CDI on corrosion behavior and effect of CDI exhibit more significantly under low strain rate.


2011 ◽  
Vol 399-401 ◽  
pp. 1972-1975 ◽  
Author(s):  
Hui Min Zhang ◽  
Lin Wu ◽  
Zhao Hui Ouyang ◽  
De Lian Yi ◽  
Qiao Hua ◽  
...  

In this paper, an organic/inorganic molybdenum series Cr-free coating was formed on galvanized steel by simple immersion and its corrosion behavior was compared to that of a typical chromate coating. Molybdate and 1-Hydroxy-ethylidene-1, 1-diphosphonic acid (HEDP) were used as corrosion inhibitor, as well as acrylic resin and silane were used as film-former and coupling agents, respectively. The corrosion behavior of the coatings was evaluated by Neutral salt spray (NSS), Electrochemical impedance spectroscopy (EIS) and Tafel polarization. The surface topography of the samples was observed by Scanning Electron Microscopy (SEM). The results indicated that the corroded area of the Mo-HEDP treatment was only corroded 2% after 72 h spraying, while the corrosion behaviour of Mo-HEDP was closed to that of Cr pretreatment due to the synergistic reaction of molybdate and HEDP. Compared with the film of Cr treatment, Mo-HEDP passivating coating was more environmentally friendly.


2014 ◽  
Vol 1056 ◽  
pp. 30-33
Author(s):  
Ai Jun Yan ◽  
Yu Pei Shao ◽  
Yu Na Wang ◽  
Shu Qi Zhao ◽  
Qiang Qiang Liao

The corrosion behavior of galvanized steel for grounding grids in the red clay soil was studied by electrochemical impedance spectroscopy (EIS) and polarization curve measurement. The results show that the Iron-Aluminitma oxides can promote the galvanized steel corrosion in red solution. The resistance decreased with the increase of immersion time and the latter stage is less than the early stage. The corrosion current density of galvanized steel decreased with the increase of the content of Iron-Aluminitma oxides of soil solution.


2010 ◽  
Vol 146-147 ◽  
pp. 1375-1378
Author(s):  
Chong Yang Liu ◽  
Gui Chang Liu ◽  
Sui Lin Wang ◽  
Li Da Wang

Ni-Cu-P coating was synthesized on copper substrate by electroless plating technique. The coating composition and corrosion resistance of Ni-Cu-P coating were characterized using energy-dispersive X-ray (EDX), electron probe micro-analyzer (EPMA), polarization curve (PC) and electrochemical impedance spectrum (EIS). The results show that the chemical nature of anions plays very important roles in the corrosion behavior of Ni-Cu-P coating. At a higher electrolyte concentration, Cl- and SO4 2- ions tend to promote the dissolution rate of Ni by their adsorption, while at lower electrolyte concentrations, NO3 - ions tend to dominate the dissolution rate of Ni-Cu-P coating.


2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Zhiquan Huang ◽  
Jinchao Zou ◽  
Junpeng Wang ◽  
Yanjie Pei ◽  
Renyao Huang ◽  
...  

The present study aims to investigate the effect of a prefabricated-crown rolling process on the corrosion characteristic of the AZ31 magnesium alloy. Specimens made of the AZ31 alloy were rolled under various crown conditions, and their microstructure evolution and corrosion behavior were analyzed. The corrosion behavior was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion-current density of the AZ31 alloy with a side pressure of 37.5 % of the plate thickness of the precast convexity decreased from 3.79 × 10–6 A/cm2 to 1.80 × 10–6 A/cm2, and the difference between the edge and the middle of the AZ31 alloy was shortened from 2.05 × 10–6 A/cm2 to 1.14 × 10–6 A/cm2. The charge-transfer resistance also increased from 507.1 Ω·cm2 to 581.2 Ω·cm2. The improvement in the corrosion resistance is a result of the more stable corrosion products and microstructure refinement formed after the prefabricated-crown rolling process.


2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Zhihong Zhang ◽  
Baoying Wang ◽  
Yijing Zhang ◽  
Gehong Zhang ◽  
Yujing Wang

A novel heteropoly acid salt, Na6[Ni(Mo11ZrO39)]·20H2O, has been synthesized by the means of acidification and adding the reactants into the solution step by step. The heteropoly compound was characterized by elemental analysis, TGA/DSC, infrared spectrum, ultraviolet spectrum, X-ray diffraction, and SEM. Its protonic conduction was measured by the means of the electrochemical impedance spectrum. The results showed that it belongs to the Keggin type, and its conductivity value was 1.23 × 10–2 S/cm at 23°C when the relative humidity was 60%, and the conductivity enhanced with the elevated temperature. Its proton conduction mechanism was in accordance with vehicle mechanism, and the activation energy was 27.82 kJ/mol.


NANO ◽  
2020 ◽  
Vol 15 (07) ◽  
pp. 2050089
Author(s):  
Litong Niu ◽  
Shaoping Hu ◽  
Yali Ma ◽  
Mingming Wang ◽  
Bolin Lv ◽  
...  

Novel ZnIn2S4/FeUiO-66 (ZFeU) photocatalyst with different proportion of FeUiO-66 has been successfully prepared by a facile one-pot solvothermal reaction. The as-synthesized nanocomposites have been thoroughly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), Brunauer–Emmett–Teller (BET) characterization, photoluminescence (PL) analysis and electrochemical impedance spectrum (EIS). The photocatalytic performance of ZFeU nanocomposites for the photodegradation of RhB under visible light irradiation was better than that of ZnIn2S4 and FeUiO-66 alone. The experiment results showed the 20% ZFeU nanocomposites had the best photocatalytic properties. At the same time, a probable mechanism was discussed and it was believed that introduction of FeUiO-66 on ZnIn2S4 would minimize the recombination of photogenerated electron-hole pairs, leading to the enhancement of the photocatalytic activity.


2017 ◽  
Vol 60 (5) ◽  
pp. 1439-1443 ◽  
Author(s):  
Guohua Hui ◽  
Yibin Ying

Abstract. A quantitative rapid analysis method for ofloxacin detection in raw milk using molecule-specific recognition and an electrochemical impedance spectrum (EIS) technique was investigated in this study. An association complex (AC) formed by a combination of ofloxacin and sodium tetraphenylboron (ST) was used as the active material for electrochemical analysis. A carbon screen-printed electrode (CSE) was modified with the AC to form an electrochemical active membrane for ofloxacin detection. EIS data of pretreated raw milk samples were measured and analyzed with a non-linear bistable stochastic resonance (SR) model. Trace ofloxacin concentrations were characterized by SR output signal-to-noise ratio (SNR) eigen values. An ofloxacin quantitative analysis model was built based on SNR eigen values. Experimental results demonstrated that the proposed method presented good accuracy, repeatability, and recovery. It is a promising way for ofloxacin detection in raw milk. Keywords: Association complex, Electrochemical impedance spectrum, Ofloxacin, Quantitative analysis, Sodium tetraphenylboron.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Sheng-xue Yu ◽  
Rui-jun Zhang ◽  
Yong-fu Tang ◽  
Yan-ling Ma ◽  
Wen-chao Du

Nanostructured conversion coating of Al-Mg alloy was obtained via the surface treatment with zirconium titanium salt solution at 25°C for 10 min. The zirconium titanium salt solution is composed of tannic acid 1.00 g·L−1, K2ZrF60.75 g·L−1, NaF 1.25 g·L−1, MgSO41.0 g/L, and tetra-n-butyl titanate (TBT) 0.08 g·L−1. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectrum (FT-IR) were used to characterize the composition and structure of the obtained conversion coating. The morphology of the conversion coating was obtained by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Results exhibit that the zirconium titanium salt conversion coating of Al-Mg alloy contains Ti, Zr, Al, F, O, Mg, C, Na, and so on. The conversion coating with nm level thickness is smooth, uniform, and compact. Corrosion resistance of conversion coating was evaluated in the 3.5 wt.% NaCl electrolyte through polarization curves and electrochemical impedance spectrum (EIS). Self-corrosion current density on the nanostructured conversion coating of Al-Mg alloy is9.7×10-8A·cm-2, which is only 2% of that on the untreated aluminum-magnesium alloy. This result indicates that the corrosion resistance of the conversion coating is improved markedly after chemical conversion treatment.


2012 ◽  
Vol 05 (04) ◽  
pp. 1250040 ◽  
Author(s):  
XIA TONG ◽  
WEN WU ◽  
SHENGMING ZHOU ◽  
QINGYIN WU ◽  
FAHE CAO ◽  
...  

Highly proton-conducting hybrid materials ( P2W17V /PEG and P2W17V/PEG/SiO2 ) were prepared by heptadecatungstovanadodiphosphoric heteropoly acid with Dawson structure ( P2W17V , 90 wt.%), polyethylene glycol (PEG, 10 wt.% and 5 wt.%) and silica gel ( SiO2 , 0 wt.% and 5 wt.%). The products were characterized by the infrared (IR) spectrum, X-ray powder diffraction (XRD) analysis and electrochemical impedance spectrum (EIS). The result reveals that their conductivity values are 1.02 × 10-2 and 2.58 × 10-2S ⋅ cm-1 at room temperature (26°C) and 75% relative humidity (RH), respectively. Their conductivities increase with higher temperature and these activation energies of proton conduction are 9.51 and 14.95 kJ⋅mol-1, which are lower than that of pure heteropoly acid (32.23 kJ⋅mol-1). These mechanisms of proton conduction for these two materials are Grotthuss mechanism.


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