Electrochemical Behavior of Fe-Cr-Mo-C-B Amorphous Alloy Coating in HCl Solution

2011 ◽  
Vol 291-294 ◽  
pp. 18-23
Author(s):  
Qing Jun Chen ◽  
Lin Li Hu ◽  
Xian Liang Zhou ◽  
Xiao Zhen Hua

The corrosion behavior of Fe44Cr16Mo16C18B6amorphous alloy coating was studied by electrochemical polarization curves and electrochemical impedance spectroscopy (EIS) in different HCl concentration solution at room temperature. Experimental results show that the polarization curves of the coating present a wide passivation range under open circuit potential and icorrincrease from 1.049×10-5A/cm2to 1.487×10-5A/cm2with HCl solution from 0.5M to 2.0M. The EIS of coating are composed of high-frequency inductive loop and low-frequency capacitance arc, which is different from the EIS of other amorphous alloys, the Rt is up to 5789Ω·cm2in 2M HCl solution. The especial equivalent circuit model R(RL)(Q(R(QRW))) can better interpret the corrosion behavior of the amorphous alloy coating.

2011 ◽  
Vol 291-294 ◽  
pp. 65-71 ◽  
Author(s):  
Qing Jun Chen ◽  
Lin Li Hu ◽  
Xian Liang Zhou ◽  
Xiao Zhen Hua ◽  
Ying Jun Yang

The purpose of this study is to investigate the electrochemical properties of Fe44Cr16Mo16C18B6amorphous alloy coating fabricated using high velocity oxygen fuel (HVOF) technology in 2.0M HCl and NaOH solution at room temperature(25°C). Based on the potentiodynamic polarization curves and Electrochemical Impedance Spectroscopy(EIS) testing results of coating in aqueous solutions of HCl and NaOH, the corrosion resistance of Fe44Cr16Mo16C18B6amorphous alloy coating in HCl solution was superior to that in NaOH solution. The icorrwas 1.487×10-5A·cm-2in HClsolution and 1.107×10-4A·cm-2in NaOH solution, while the Rtreach to 5.789×104Ω·cm2and 9780Ω·cm2, respectively. On the other hand, these corrosion phenomenon could be better interpreted by R(Q(R(RQW)))(RL) and R(RL)(Q(R(CW))) equivalent circuit model, which were different from that of other Fe-based amorphous alloys in HCl and NaOH solution, respectively.


2018 ◽  
Vol 65 (4) ◽  
pp. 430-435 ◽  
Author(s):  
H.T. Rahal ◽  
A.M. Abdel-Gaber ◽  
R. Awad ◽  
B.A. Abdel-Naby

Purpose The paper aims to examine the inhibition effect of NiO nanoparticles and the influence of liquid nitrogen immersion on the corrosion behavior of (NiO)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ and (NiO)x (Bi, Pb 2223), where x = 0.00 and 0.05 Wt.% phase superconductor in 0.1 M Na2SO4 at 30°C. Design/methodology/approach This study was done using open-circuit potential electrochemical impedance spectroscopy, potentiodynamic polarization curves and chronoamperometry measurements. Findings Potentiodynamic polarization technique showed that NiO nanoparticles suppress both the anodic and cathodic parts of the polarization curves of (NiO)x(Bi, Pb)-2223 superconductor in 0.1 M Na2SO4 solution. A significant enhancement in the corrosion resistance of the prepared superconductors is observed on immersing them in liquid nitrogen. This is owing to the fact that immersion in liquid nitrogen increases the volume contraction of the superconductor matrix, causing the shrinkage of the pores and voids present in the samples and thus reducing the active surface area for the dissolution of (NiO)x(Bi, Pb)-2223 superconductor matrix. Originality/value This paper fulfills the need to investigate the corrosion behavior of superconductors and the influence of liquid nitrogen immersion on such behavior.


2013 ◽  
Vol 781-784 ◽  
pp. 299-303
Author(s):  
Shu Lan Cai ◽  
Kang Quan Qiao ◽  
Fa Mei Feng

A new corrosion inhibior N,N-diethylammonium O,O-di (p-chlorophenyl) dithiophosphate (EDPDP) has been synthesized and its inhibition effect towards the corrosion of carbon steel in 1.0 molL-1 HCl solution at 25 °C has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The obtained results show that EDPDP is a excellent inhibitor and the inhibition efficiencies exceed 90 %. The polarization measurements reveal that EDPDP is a mixed type inhibitor and the equivalent circuit model of the corrosion inhibition process is obtained by the analysis of EIS data.


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.


2002 ◽  
Vol 67 (6) ◽  
pp. 425-436 ◽  
Author(s):  
Houy Ma ◽  
Shenhao Chen ◽  
Chao Yang ◽  
Jingli Luo

The effect of nitrate ions on the electrochemical behaviour of iron (ferrite) and two carbon steels (martensite and pearlite) in sulphate solutions of different pH values was investigated by cyclic voltammetry polarization and electrochemical impedance spectroscopy. The pitting inhibiting effect of nitrate ions on ferrite in sulphate media is pH dependent. Nitrate ions were unable to inhibit the pitting on ferrite in neutral sulphate solutions, but did effectively protect passivated ferrite from pitting in acidic sulphate solutions. No pitting occurred on the surface of the martensite and pearlite specimens in sulphate solutions regardless of the pH of the solutions. At the open-circuit corrosion potentials, the three materials underwent general corrosion. The impedance spectra for the three materials measured in neutral sulphate solutions containing nitrates and chlorides at the corrosion potentials all showed a capacitive loop, while in acidic sulphate solutions their impedance spectra were greatly reduced in size and displayed at least a low frequency impedance loop (inductive or capacitive loop) besides the well-known high frequency capacitive loop. The variation of the impedance behaviour with pH is explained.


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.


2020 ◽  
Vol 1012 ◽  
pp. 401-406
Author(s):  
Carlos Trivellato de Carvalho Filho ◽  
Pedro Paiva Brito

In the present work, the friction surfacing process was applied to manufacture aluminum alloy (AA6351) coatings on low carbon steel (AISI 1020) substrates. After friction surfacing the AA6351 deposited coatings were submitted to two finishing process in order to adjust surface roughness: milling and milling followed by sanding. The corrosion behavior of the two finishing process was compared with the as-deposited condition in order to determine the influence of surface roughness on the corrosion resistance of friction surfacing coatings. The corrosion behavior was examined by electrochemical impedance spectroscopy and potentiodynamic polarization in a 3.5wt.%NaCl solution containing naturally dissolved O2. The results obtained indicated that the elevated surface roughness observed in the as-deposited condition led to relatively lower corrosion resistance in comparison, with lower values for polarization resistance and more anodic corrosion potential.


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.


2016 ◽  
Vol 835 ◽  
pp. 115-120
Author(s):  
Francis Mulimbayan ◽  
Manolo G. Mena

All materials which are intended to have in contact with food and other commodities produced or processed for human consumption are called food contact materials (FCM’s). Stainless steel (SS) – a widely known metallic FCM is used mainly in processing equipment, containers and household utensils. It is known for having numerous industrial and domestic applications worldwide due to its special characteristics of having notable corrosion resistance. However, this corrosion resistance is not all-encompassing since SS may still undergo degradation when subjected to a specific corrosion-inducing environment. SS may be classified according to its microstructure. If the atoms which make up the SS can be viewed as having a face-centered cubic structure, then the alloy is said to be austenitic. This SS grades include the conventional 300-series and the newly-developed 200-series. The former has superior corrosion resistance while the latter is far cheaper. In this study, the corrosion behavior of AISI 202 SS in two different levels of dissolved oxygen (O2) and three acid concentrations was investigated using electrochemical techniques, namely, open-circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS). As the concentration of citric acid is increased, the measured OCP values of the alloy decreased and the polarization resistance (Rp) decreased, indicating decrease in alloy stability and decline in the corrosion resistance, respectively. With regards to effects of dissolved O2, results revealed that increasing the level of dissolved O2 has consequently increased the polarization resistance and shifted the OCP to more positive values. All the generated Nyquist plots exhibited a depressed capacitive loops indicating that corrosion in the designated solution occurred with charge transfer as the rate-determining step.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
A. Fattah-alhosseini ◽  
M. Ranjbaran ◽  
S. Vajdi Vahid

Corrosion behavior of A356-10 vol.% SiC composites cast by gravity and squeeze casting is evaluated. For this purpose, prepared samples were immersed in H2SO4solution for 2 hrs. at open circuit potential. Tafel polarization and electrochemical impedance spectroscopy (EIS) were carried out to study the corrosion resistance of composites. The results showed that corrosion resistance of composites cast by squeeze casting is higher than that of the gravity cast composites. The micrographs of scanning electron microscope (SEM) clearly showed the squeeze casting composites exhibit a good dispersion/matrix interface when compared with composites produced by gravity casting.


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