scholarly journals High-Performance Mg–Al–Bi Alloy Anode for Seawater Batteries and Related Mechanisms

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1362
Author(s):  
Changqing Wu ◽  
Xu Meng ◽  
Wei Wang
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Performance ◽  
Electrochemical Properties ◽  
High Performance ◽  
Electrochemical Impedance ◽  
Immersion Test ◽  
Utilization Efficiency ◽  
Discharge Process ◽  
Nacl Solution ◽  
Galvanostatic Discharge

Bi, a group 15 element, was added to magnesium alloys and applied to seawater batteries in marine operating machinery to improve the electrochemical performance and corrosion resistance of the battery. The electrochemical properties of as-cast pure Mg, Mg–8Al, and Mg–8Al–xBi alloy anodes in 3.5% NaCl solution were researched. Electrochemical impedance spectroscopy and an immersion test in 3.5% NaCl solution show that the Mg–8%Al–0.4%Bi alloy provides better corrosion resistance than Mg and the Mg–8Al alloy. The galvanostatic discharge results show that the Mg–8%Al–0.4%Bi alloy revealed better electrochemical properties and utilization efficiency in 3.5% NaCl solution. The Mg17Al12 and BiOCl phases formed during the discharge process of the Mg–8%Al–0.4%Bi alloy play an important role in improving the electrochemical performance and utilization efficiency of the alloy.

Effect of Coating Thickness on the Corrosion Behavior of Galvanized Steel in 3.5 % NaCl Solution

2021 ◽  
Vol 882 ◽  
pp. 35-49
Author(s):  
A.D. Vishwanatha ◽  
Bijayani Panda ◽  
J.N. Balaraju ◽  
Preeti Prakash Sahoo ◽  
P. Shreyas
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Product ◽  
Corrosion Behavior ◽  
Coating Thickness ◽  
Electrochemical Impedance ◽  
Immersion Test ◽  
Carbon Steels ◽  
Galvanized Steel ◽  
Uniform Corrosion ◽  
Nacl Solution

Corrosion behavior of three carbon steels with increasing galvanized coating thickness of 5.6, 8.4 and 19.2 μm named as T1, T2 and T3, respectively, was studied by immersion test, potentiodynamic polarization and electrochemical impedance spectroscopy in freely aerated 3.5% NaCl solution. The major phase in the corrosion product of all the samples after immersion test was found to be zincite, as determined by X-Ray Diffraction and Fourier Transform Infrared Spectroscopy techniques. The corrosion product on sample T1was well adhered and was compact in most regions. Samples T2 and T3 showed porous and non-adherent growth of corrosion product. Corrosion rates were found to increase with increasing coating thickness. The impedance provided by the coating as well as the substrate was the highest for the sample with thinnest coating (T1). The early exposure of the underlying steel in sample T1 resulted in higher corrosion resistance, which was probably due to the combined effect of zinc corrosion products and Fe-Zn alloy layer. Higher amount of protective γ-FeOOH as well as compact corrosion product could have also improved the corrosion resistance of sample T1. Although the average uniform corrosion resistance was higher for T1, the localized pitting corrosion was also observed, probably due to the thin galvanized layer.

Corrosion Resistance of Mo-Fe-Ti Alloy for Overpack in Simulating Underground Environment

2010 ◽  
Author(s):  
Toshiyasu Nishimura
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Selective Dissolution ◽  
Immersion Test ◽  
Ti Alloy ◽  
Nacl Solution ◽  
Β Phase ◽  
Heat Treated

In order to examine the application of Mo-Fe-Ti alloy for overpak, the corrosion resistance of heat-treated its alloys was investigated by Electrochemical impedance spectroscopy (EIS), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM) and Energy dispersive X-ray analysis (EDAX). Considering the welding, the sample subjected to solution heat treatment (ST) had a single β phase and samples subjected to aging heat treatment at 600–700°C had a-phase precipitation in b-phase. EIS results showed that the corrosion resistance of the aging heat-treated samples was lower than that of the ST sample, but much higher than that of pure Ti in long term immersion test in 10% NaCl solution of pH 0.5 at 97°C which simulating the crevice solution. Laser micrographs of the aging heat-treated samples indicated that a-phase at the grain boundary and in the grain was selectively corroded and caused selective dissolution in NaCl solution. The results of TEM combined with EDAX analyses showed that there were b-phase matrix composed of 2.7 wt% of Mo and 4.8wt% of Fe, and a-phase composed of 0.7 wt% of Mo and 0.1 wt% of Fe in sample aged at 600°C. Thus, Mo-poor a-phase was selectively dissolved in in 10% NaCl solution of pH 0.5 at 97°C. In a result, the ST sample of only b-phase showed the highest resistance, and aging heat-treated samples containing a-phase (0.7 wt% of Mo) showed higher values than pure Ti in the corrosion test. Addition of Fe did not decrease the resistance of alloy in the case of ST condition. Moreover, as Fe was involved in b-phase with Mo which increased remarkably the corrosion resistance, the addition of Fe did not decrease the corrosion resistance of aging heat-treated Mo-Fe-Ti alloy. Finally, it was concluded that Mo-Fe-Ti alloy had excellent resistance for overpack in simulating underground environment.

Corrosion Resistance of Mg-Li Alloys Subjected to Different Heat Treatment

2014 ◽  
Vol 1044-1045 ◽  
pp. 164-167
Author(s):  
D.R. Fang ◽  
F.F. Liu ◽  
Li Wei Quan ◽  
Jing Yang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Aging Treatment ◽  
Immersion Test ◽  
Annealed Sample ◽  
Nacl Solution ◽  
Aged Sample ◽  
Electrochemical Impedance Spectroscopy Measurement ◽  
Cast Sample

Casting Mg-Li alloy samples were subjected to annealing and aging treatment respectively, and the corrosion resistance of different samples was investigated by immersion test and electrochemical impedance spectroscopy measurement in 3.5% NaCl solution. The results show that the corrosion resistance of the as-cast sample is the best,the aged sample is the second, and the annealed sample is the worst to resist corrosion.

scholarly journals Assessment of nickel titanium and beta titanium corrosion resistance behavior in fluoride and chloride environments

2013 ◽  
Vol 83 (5) ◽  
pp. 864-869 ◽  
Author(s):  
Elisa J. Kassab ◽  
José Ponciano Gomes
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Fluoride Concentration ◽  
Nickel Titanium ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Nacl Solution ◽  
Galvanic Coupling ◽  
Beta Titanium

ABSTRACT Objective: To assess the influence of fluoride concentration on the corrosion behavior of nickel titanium (NiTi) superelastic wire and to compare the corrosion resistance of NiTi with that of beta titanium alloy in physiological solution with and without addition of fluoride. Materials and Methods: NiTi corrosion resistance was investigated through electrochemical impedance spectroscopy and anodic polarization in sodium chloride (NaCl 0.15 M) with and without addition of 0.02 M sodium fluoride (NaF), and the results were compared with those associated with beta titanium. The influence of fluoride concentration on NiTi corrosion behavior was assessed in NaCl (0.15 M) with and without 0.02, 0.04, 0.05, 0.07, and 0.12 M NaF solution. Galvanic corrosion between NiTi and beta titanium were investigated. All samples were characterized by scanning electron microscopy. Results: Polarization resistance decreased when NaF concentration was increased, and, depending on NaF concentration, NiTi can suffer localized or generalized corrosion. In NaCl solution with 0.02 M NaF, NiTi suffer localized corrosion, while beta titanium alloys remained passive. Current values near zero were observed by galvanic coupling of NiTi and beta titanium. Conclusions: There is a decrease in NiTi corrosion resistance in the presence of fluoride. The corrosion behavior of NiTi alloy depends on fluoride concentration. When 0.02 and 0.04 M of NaF were added to the NaCl solution, NiTi presented localized corrosion. When NaF concentration increased to 0.05, 0.07, and 0.12 M, the alloy presented general corrosion. NiTi corrosion resistance behavior is lower than that of beta titanium. Galvanic coupling of these alloys does not increase corrosion rates.

Corrosion Resistance of Nd-Fe-B Magnets Coated with Polypyrrole Films

2006 ◽  
Vol 530-531 ◽  
pp. 111-116
Author(s):  
M.C.E. Bandeira ◽  
F.D. Prochnow ◽  
Isolda Costa ◽  
César V. Franco
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Nacl Solution ◽  
Corrosion Performance ◽  
Low Frequencies ◽  
Polypyrrole Films ◽  
Phosphate Ions ◽  
Polypyrrole Film ◽  
Corrosive Environments ◽  
Magnet Surface

Nd-Fe-B magnets present outstanding magnetic properties. However, due to their low corrosion resistance, their applications are limited to non-corrosive environments. Nowadays, significant efforts are underway to increase the corrosion resistance of these materials, through the use of coatings. Herein are presented the results of a study on the corrosion resistance of Nd-Fe-B magnets coated with polypyrrole (PPY). The electrochemical behavior of coated and uncoated magnets has been studied by Electrochemical Impedance spectroscopy (EIS) in synthetic saliva. The results were compared to previous investigations, which were carried out under similar conditions, in Na2SO4 and NaCl solutions. In sulphate solution, the corrosion resistance of the PPY-coated magnet was 3 times larger (1600 .cm2) than that of uncoated magnet (500 .cm2). In NaCl solution, however, the corrosion resistance of coated and uncoated magnets were very similar (250 .cm2). In synthetic saliva, both the uncoated and coated magnets presented good corrosion performance (1940 .cm2). Such behavior can be attributed to the phosphate ions in saliva, which play a role as corrosion inhibitor, producing phosphating, at least partially, of the magnet surface. The PPY-coated magnets presented a strong diffusional control from moderate to low frequencies, caused by the polypyrrole film. The thicker PPY film increased the corrosion resistance of the magnet in synthetic saliva.

Corrosion characteristics of plasma spray, arc spray, high velocity oxygen fuel, and diamond jet coated 30MnB5 boron alloyed steel in 3.5 wt.% NaCl solution

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bekir Güney ◽  
Yusuf Dilay ◽  
Moses M. Solomon ◽  
Hüsnü Gerengi ◽  
Adem Özkan ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Plasma Spray ◽  
High Velocity ◽  
Electrochemical Impedance ◽  
Iron Carbide ◽  
Alloyed Steel ◽  
Coated Sample ◽  
Nacl Solution ◽  
Arc Spray ◽  
Coated Surfaces

Abstract 30MnB5 boron alloyed steel surface is coated using different coating techniques, namely 60(Ni-15Cr-4.4Si-3.5Fe-3.2B 0.7C)-40(WC 12Co) metallic powder plasma spray, Fe-28Cr-5C-1Mn alloy wire arc spray, WC-10Co-4Cr (thick) powder high velocity oxy-fuel (HVOF), and WC-10Co-4Cr (fine) diamond jet HVOF. The microstructure of the crude steel sample consists of ferrite and pearlite matrices and iron carbide structures. The intermediate binders are well bonded to the substrate for all coated surfaces. The arc spray coated surface shows the formation of lamellae. The cross-section of HVOF and diamond jet HVOF coated surfaces indicates the formation of WC, W2C Cr, and W parent matrix carbide structures. The corrosion characteristic of the coated steel has been investigated in 3.5 wt.% NaCl solution using electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDAX) techniques. The results reveal that the steel corroded in the medium despite the coatings. However, the extent of corrosion varies. HVOF coated sample demonstrated the highest corrosion resistance while arc spray coated sample exhibited the least. EDAX mapping reveals that the elements in the coatings corroded in the order of their standard electrode potential (SEP). Higher corrosion resistance of HVOF coated sample is linked to the low SEP of tungsten.

Improved Corrosion Resistance and Increased Hardness of Copper Substrates from Cu-Ni/Ni-P Composite Coatings

MRS Advances ◽  
2020 ◽  
Vol 5 (40-41) ◽  
pp. 2129-2137 ◽  
Author(s):  
Wenwen Dou ◽  
Wen Li ◽  
Yuchen Cai ◽  
Mengyao Dong ◽  
Xiaojing Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Copper Substrate ◽  
Electrolytic Deposition ◽  
Deposition Method ◽  
Nacl Solution ◽  
Current Densities ◽  
Superior Corrosion Resistance ◽  
Deposition Conditions

ABSTRACTTo improve the corrosion resistance and to increase the hardness of copper substrate in marine environment, the Cu-Ni/Ni-P composite coatings were prepared on the copper substrate using the galvanostatic electrolytic deposition method. The deposition current densities were explored to find the optimized deposition conditions for forming the composite coatings. Corrosion resistance properties were analyzed using the polarization curves and electrochemical impedance spectroscopy (EIS). Considering the corrosion resistance and hardness, the −20 mA/cm2 was selected to deposit Cu-Ni coatings on copper substrate and the −30 mA/cm2 was selected to deposit Ni-P coating on the Cu-Ni layer. The Cu-Ni/Ni-P composite coatings not only exhibited superior corrosion resistance compared to single Cu-Ni coating in 3.5 wt.% NaCl solution, but also showed much better mechanical properties than single Cu-Ni coating.

Synthesis of urchin-like Ni3Si2O5(OH)4 hierarchical hollow spheres/GO composite with enhanced electrochemical properties for high-performance hybrid supercapacitors

2019 ◽  
Vol 48 (31) ◽  
pp. 11749-11762 ◽  
Author(s):  
Xueying Dong ◽  
Yifu Zhang ◽  
Qiushi Wang ◽  
Xiaorong Zhang ◽  
Meng Gao ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Electrochemical Properties ◽  
Hollow Sphere ◽  
High Performance ◽  
Hollow Spheres ◽  
Capacity Retention ◽  
Hybrid Supercapacitors ◽  
Enhanced Electrochemical Performance

Urchin-like Ni3Si2O5(OH)4 hierarchical hollow sphere/GO composites were synthesized, which showed an enhanced electrochemical performance of 165 F g−1 at 0.5 A g−1 and 84% capacity retention after 5000 cycles.

scholarly journals Effects of NiSO4 Concentration on the Coloring Performance and Corrosion Resistance of the Colored Film on 304 Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 598
Author(s):  
Wenwei Li ◽  
Jun-e Qu ◽  
Zhiyong Cao ◽  
Hairen Wang
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Negative Impact ◽  
304 Stainless Steel ◽  
Nacl Solution ◽  
Time Curve ◽  
Steel Surfaces

The colored films were successfully prepared on the 304 stainless steel surfaces in coloring solutions with different NiSO4 contents. The purpose of this study was to investigate the effects of NiSO4 in the coloring solution on the coloring performance of 304 stainless steel and corrosion resistance of the obtained colored film in NaCl solution. The coloring rate was determined from coloring potential-time curve, and the protection properties of the color films in a 3.5% NaCl solution were characterized by potentiodynamic polarization scan, electrochemical impedance spectroscopy, and wear resistance test. The results showed that adding NiSO4 could accelerate the coloring process but brought about a negative impact on the surface’s corrosion resistance.

scholarly journals Influence of SiO2 Content and Exposure Periods on the Anticorrosion Behavior of Epoxy Nanocomposite Coatings

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 118 ◽  
Author(s):  
Alam ◽  
Samad ◽  
Sherif ◽  
Poulose ◽  
Mohammed ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
High Performance ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
Sio2 Nanoparticles ◽  
Epoxy Coating ◽  
Properties Of Coatings ◽  
Ft Ir ◽  
Eis Measurements ◽  
Coating Formulations

Epoxy coating formulations containing 1%, 3%, and 5% SiO2 nanoparticles were produced and applied on a mild steel substrate to achieve the objective of high performance corrosion resistance. The electrochemical impedance spectroscopy (EIS) technique was employed to measure the anticorrosive properties of coatings. The corrosion tests were performed by exposing the coated samples in a solution of 3.5% NaCl for different periods of time, varied from 1 h and up to 30 days. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analyses revealed the presence of nanoparticles in the final cured samples. Establishing the incorporation of the nanoparticles in the coating formulations was confirmed by employing both of XRD and FT-IR techniques. The FT-IR spectra have proved to be satisfactory indicating that there was a complete reaction between the epoxy resin with the hardener. EIS measurements confirmed that the presence and the increase of SiO2 nanoparticles greatly improved the corrosion resistance of the epoxy coating. The highest corrosion resistance for the coatings was obtained for the formulation with 5% SiO2 nanoparticles content, particularly with prolonging the immersion time to 30 days.

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