D.C. etching anode aluminum foil to form branch tunnels by electroless depositing Cu

2019 ◽  
Vol 66 (6) ◽  
pp. 697-703
Author(s):  
Zhenqi Liu ◽  
Jie Wang ◽  
Jianhan Chen ◽  
Xiya Liu ◽  
Yibin Yin ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Design Methodology ◽  
Acidic Solution ◽  
Electrochemical Impedance ◽  
Aluminum Foil ◽  
Electrolytic Capacitor ◽  
Nacl Solution ◽  
Content Type ◽  
Interior Surface ◽  
Corrosion Cell

Purpose The purpose of this study is to explore the mechanism of branch pits and tunnels formation and increase the specific surface area and capacitance of anode Al foil for high voltage electrolytic capacitor by D.C. etching in acidic solution and neutral. Design/methodology/approach Al foil was first D.C. etched in HCl-H2SO4 mixed acidic solution to form main tunnels perpendicular to the Al surface, and then D.C. etched in neutral NaCl solution including 0.5 per cent C6H8O7 and Cu(NO3)2 with different concentration to form branch tunnels normal to Al surface. Between two etching, Cu nuclei were electroless deposited on the interior surface of main tunnels by natural occluded corrosion cell effect to form micro Cu-Al galvanic local cells. The effects of electroless deposited Cu nuclei on cross-section etching morphologies and electrochemical behavior of Al foil was investigated with SEM, polarization curve and electrochemical impedance spectroscopy (EIS). Findings The results show that sub branch tunnels can form along the main tunnels owing to the formation of Cu-Al micro-batteries, in which Cu is cathode and Al is anode. With increase in Cu(NO3)2 concentration, more Cu nuclei can be electroless deposited and serve as the favorable sites for branch tunnel initiation along the whole length of main tunnels, leading to enhancement in specific capacitance of anode Al foil. Originality/value Cu nuclei were electroless deposited on the interior surface of main tunnels by natural occluded corrosion cell effect to form micro Cu-Al galvanic local cells, which can serve as the favorable sites for branch tunnel initiation along the main tunnels to enhance specific capacitance of anode Al foil.

Etching Anode Foil with Branch Tunnels for Aluminum Electrolytic Capacitors

2019 ◽  
Vol 19 (11) ◽  
pp. 7471-7475 ◽  
Author(s):  
Chao-Lei Ban ◽  
Jian-Hai Chen ◽  
Fang-Ren Wang ◽  
Shu-Qin Zhu ◽  
Zhen-Qi Liu
Keyword(s):  
Cross Section ◽  
Acidic Solution ◽  
Electrochemical Impedance ◽  
Electrolytic Capacitor ◽  
Nacl Solution ◽  
Aluminum Electrolytic Capacitor ◽  
Electrolytic Capacitors ◽  
Corrosion Cell ◽  
Anode Foil ◽  
Aluminum Electrolytic Capacitors

Al foil for high-voltage aluminum electrolytic capacitor was first D.C. etched in HCl–H2SO4 mixed acidic solution to form main tunnels and then D.C. etched in natural NaCl solution containing 0.1% H2C2O4 and different trace amounts of Zn(NO3)2. Between the two etching processes, Zn nuclei were deposited on the interior surface of the main tunnels by the natural occluded corrosion cell effect to form micro Zn–Al galvanic local cells. The effects of Zn nuclei on the cross-section etching and electrochemical behavior of Al foil were investigated using scanning electron microscopy, polarization curve measurement, and electrochemical impedance spectroscopy. The sub-branch tunnels can form along the main tunnels owing to the formation of Zn–Al micro-batteries, in which Zn is the cathode and Al is the anode. Increasing Zn(NO3)2 concentration increases the number of Zn nuclei that can serve as sites for branch tunnel initiation along the main tunnels, thereby enhancing the specific capacitance of etched Al foil.

Applicability of EIS for evaluation of corrosion resistance of aluminum flakes

2016 ◽  
Vol 63 (5) ◽  
pp. 355-359
Author(s):  
Naghmeh Amirshaqaqi ◽  
Mehdi Salami-Kalajahi ◽  
Mohammad Mahdavian
Keyword(s):  
Corrosion Resistance ◽  
Conventional Method ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Quantitative Estimation ◽  
Surface Modifications ◽  
Organic Coatings ◽  
Nacl Solution ◽  
Content Type ◽  
Alkaline Conditions

Purpose The conventional method for evaluation of corrosion resistance of aluminum flakes is based on the volume of evolved hydrogen in acidic and basic environments. This study aims to introduce electrochemical impedance spectroscopy (EIS) as a method to evaluate corrosion resistance of aluminum flakes. Design/methodology/approach Aluminum flakes with different surface modifications were compressed to build a disk. Then, the disks were examined by EIS in NaCl solution. Also, the corrosion resistance of the flakes was evaluated by the conventional method. Findings The results revealed applicability of EIS for evaluation of corrosion resistance of aluminum flakes. Originality/value Application of EIS to evaluate corrosion resistance of aluminum flakes is novel. As it can provide fast, reliable and quantitative estimation of the corrosion resistance of the aluminum flakes in the 3.5 per cent NaCl solution. This medium is highly encountered for the aluminum flakes used in organic coatings, that is why test in NaCl solution is more convenient compared to the conventional methods using acid and alkaline conditions.

Effect of carbides on sensitivity of pitting corrosion in Inconel 718 alloy

2020 ◽  
Vol 67 (2) ◽  
pp. 158-165
Author(s):  
Xianping Wei ◽  
Wen Jie Zheng
Keyword(s):  
Pitting Corrosion ◽  
Inconel 718 ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Immersion Test ◽  
Nacl Solution ◽  
Inconel 718 Alloy ◽  
Content Type ◽  
Corrosion Susceptibility ◽  
Dynamic Electrochemical Impedance Spectroscopy

Purpose This paper aims to expand the application area of Inconel 718 alloy in marine environment, the sensitivity of pitting corrosion should be analyzed and discussed, especially the effect of block carbides. Design/methodology/approach Effect of carbides on the sensitivity of pitting corrosion for Inconel 718 alloy was carried out at 30°C in 3.5% NaCl solution using dynamic electrochemical impedance spectroscopy and anodic polarization techniques. In addition, the initiation of pitting corrosion was investigated by immersion test in 0.05 M HCl + 6% FeCl3 solution. Findings As a result, the precipitation of carbides, as the initiation of pitting corrosion, increased pitting corrosion susceptibility, especially the block carbides could lead to deep-spalling. Within that process, temperature and potential acted as the main controlling factors, and the effect of the latter was more distinct. Originality/value The initiation of pitting corrosion was revealed by the immersion test. The mechanism of pitting corrosion was analyzed and discussed.

Saccharum sinense bagasse extract as an effective corrosion inhibitor for J55 steel in 3.5% NaCl solution saturated with CO2

2015 ◽  
Vol 62 (6) ◽  
pp. 388-393 ◽  
Author(s):  
Bo Huang ◽  
Yuanhua Lin ◽  
Ambrish Singh ◽  
Eno E Ebenso ◽  
Lujiang Zhou ◽  
...  
Keyword(s):  
Corrosion Inhibitor ◽  
Design Methodology ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
Toxic Substance ◽  
Nacl Solution ◽  
Environment Friendly ◽  
Content Type ◽  
Practical Implications

Purpose – The purpose of this paper is to test bagasse extract as an effective corrosion inhibitor. Design/methodology/approach – The bagasse was extracted without any toxic substance and was found to be effective for corrosion of J55 steel. Findings – The inhibition efficiency of bagasse was more than 90 per cent in 3.5 per cent NaCl solution saturated with CO2 for corrosion inhibition of J55 steel. Research limitations/implications – The inhibition effect of Saccharum sinense bagasse extract on the corrosion of J55 steel in 3.5 weight per cent NaCl saturated with CO2 solution was investigated by means of Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, polarization curve and scanning electron microscope. Practical implications – It can be used as low-cost corrosion inhibitor. Social implications – It is an environment-friendly corrosion inhibitor. Originality/value – This work is original and carried out in Southwest Petroleum University, China. This is not communicated anywhere else.

Effects of SO42− concentration on corrosion behaviour of carbon steels

2015 ◽  
Vol 62 (5) ◽  
pp. 322-326 ◽  
Author(s):  
Zhiping Zhu ◽  
Xiaocui Jiao ◽  
Xueying Tang ◽  
Haiwei Lu
Keyword(s):  
Water Chemistry ◽  
Pitting Corrosion ◽  
Design Methodology ◽  
Competitive Adsorption ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Carbon Steels ◽  
Boiler Water ◽  
Content Type ◽  
Condition Solution

Purpose – The purpose of this paper was to investigate the effects of SO42− concentration on the corrosion behaviour of T23 and T12 steels in simulated water chemistry condition solution of 600 MW fossil-fired power boilers. Design/methodology/approach – The influence and mechanism of SO42− ions on the pitting corrosion of T23 and T12 steels in simulated oxygenated treatment water chemistry solution was studied using electrochemical potentiodynamic polarization scans and electrochemical impedance spectroscopy. Findings – The results showed that T23 and T12 were susceptible to pitting corrosion in the simulated solution with full SO42− concentration for the competitive adsorption of OH− and SO42− on the surface of steels. The pitting sensitivity of the steels improved with increasing SO42− concentration. The corrosion resistance for SO42− of T23 was stronger than that for T12. Originality/value – This study is an attempt to provide direction for regulating the concentration of SO42− in boiler water and for selecting the material for boiler water wall tubes.

Effect of metal ions on the anti-corrosion properties of γ-glycidoxypropyltrimethoxysilane coatings on cold-rolled iron

2016 ◽  
Vol 63 (2) ◽  
pp. 82-88 ◽  
Author(s):  
Shengsong Ge ◽  
Menglong Li ◽  
Qian Shao ◽  
Ke Liu ◽  
Junxiang Wang ◽  
...  
Keyword(s):  
Metal Ions ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Coating Process ◽  
Neutral Salt ◽  
Corrosion Properties ◽  
Content Type ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Cold Rolled

Purpose – This paper aims to clarify the effect of metal ions added in the γ-glycidoxypropyltrimethoxysilane (γ-GPS) solutions on the anti-corrosion properties of the γ-GPS coatings on cold-rolled iron (CRI). Design/methodology/approach – The transformations of functional groups involved in reactions during the coating process were characterized by Fourier transformed infrared spectroscopy (FTIR), and the thickness of the γ-GPS coatings on the CRI substrates was measured using high-powered microscopy. The anti-corrosion properties of γ-GPS-treated samples were evaluated by neutral salt spray tests, polarization curves and electrochemical impedance spectroscopy measurements. Findings – The results show that Zn2+ and Mg2+ in the γ-GPS solutions promote the formation of Si-O-Si and Si-O-Fe bonds and improve the anti-corrosion properties of the γ-GPS coatings on CRI. However, Al3+ and Na+ in the γ-GPS solutions do not play this role. Originality/value – Although there have been previous research studies on the γ-GPS coatings on CRI, this paper is the first to study the effect of metal ions added in the silane solutions on the anti-corrosion properties of the γ-GPS coatings, and it has been confirmed that the anti-corrosion properties changed when Zn2+ (or Mg2+) is present.

Synergistic effect of chloride and NO2 on the atmospheric corrosion of bronze

2009 ◽  
Vol 56 (6) ◽  
pp. 299-305 ◽  
Author(s):  
Xia Cao ◽  
Ning Wang ◽  
Ning Liu
Keyword(s):  
Synergistic Effect ◽  
Design Methodology ◽  
Atmospheric Corrosion ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Impedance Measurements ◽  
Content Type ◽  
X Ray ◽  
Corrosion Kinetics ◽  
Tension Tests

PurposeThe purpose of this paper is to investigate the effect of chloride along with NO2 on the atmospheric corrosion of bronze using exposure tests.Design/methodology/approachSurface tension tests and electrochemical impedance measurements together with scanning electron microscopy (SEM) with energy dispersive atomic X‐ray, and X‐ray diffraction are used to characterize the corrosion behavior.FindingsThe results of the weight loss measurements show that the whole corrosion kinetics can be described approximately by: ΔW=atb; the synergistic effect of chloride and NO2 is observed clearly, though no nitrate existed in the corrosion products.Originality/valueA new catalyst theory has been suggested in this paper, i.e. that NO2 acts as a catalyst during the corrosion process when significant quantities of chloride also are present.

Microstructure and corrosion resistance of Ni/Cr3C2-NiCr composite coating

2019 ◽  
Vol 66 (4) ◽  
pp. 471-478 ◽  
Author(s):  
Majid Hosseinzadeh ◽  
Abdol Hamid Jafari ◽  
Rouhollah Mousavi ◽  
Mojtaba Esmailzadeh
Keyword(s):  
Corrosion Resistance ◽  
Composite Coating ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Thermal Spraying ◽  
Content Type ◽  
Bath Solution ◽  
Electrochemical Deposition Method ◽  
Base Composite

Purpose In this study, electrochemical deposition method which have cheaper equipment than thermal spraying methods and is available for the production of composite coatings were used. Design/methodology/approach Composite coatings were electrodeposited from a Watts's bath solution in which the suspended Cr3C2-NiCr particles were dispersed in the bath solution during deposition. Potentiodynamic polarization and electrochemical impedance spectroscopy techniques have been used to evaluate the corrosion resistance of the composite coating in the 3.5 Wt.% NaCl solution. Findings It was found that the submicron Cr3C2-NiCr particles distributed uniformly in the coating and depend on the current density of deposition, different amount of particles can be incorporated in the coating. The results showed that the corrosion resistance of the Ni/ Cr3C2-NiCr composite coatings is more comparable to the pure nickel coating. Originality/value Production of Ni-base composite coating from an electrolytic bath containing Cr3C2-NiCr particles is possible via electrodeposition.

Study of corrosion of copper in industrial cooling systems

2015 ◽  
Vol 6 (5) ◽  
pp. 617-635 ◽  
Author(s):  
Ioannis A Kartsonakis ◽  
Elias P. Koumoulos ◽  
Antonis Karantonis ◽  
Costas A. Charitidis ◽  
S Dessypris ◽  
...  
Keyword(s):  
Design Methodology ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Water Cooling ◽  
Optimum Structure ◽  
Copper Corrosion ◽  
Cooling Systems ◽  
Content Type ◽  
Industrial Systems

Purpose – The purpose of this paper is to perform the evaluation of copper susceptibility to corrosion in industrial cooling systems. Microstructure and defects of copper are observed, while divergences from optimum structure are discussed. Design/methodology/approach – Various types of corrosion are examined. Electrochemical techniques such as electrochemical impedance spectroscopy and potentiodynamic polarisation are applied in these materials, using corrosion inhibitors. Microscopic observations and electrochemical measurements are interpreted according to possible mechanistic scenarios. Findings – It is evident that, under specific conditions (e.g. high pH), water cooling ingredients can enhance corrosion, leading to significant copper mass loss from the inner surface of the pipe and thus leading to failure. Originality/value – Evaluation of copper corrosion in cooling industrial systems was done, as well as studies of copper corrosion in sodium chloride.

Influence of tungsten carbide nanoparticles on corrosion resistance properties of electroless nickel–phosphorus coatings

2014 ◽  
Vol 61 (5) ◽  
pp. 314-318 ◽  
Author(s):  
Chunmei Zhao ◽  
Yingwu Yao
Keyword(s):  
Corrosion Resistance ◽  
Tungsten Carbide ◽  
Electrochemical Impedance ◽  
Electroless Nickel ◽  
Nanocomposite Coatings ◽  
Impedance Spectra ◽  
Nacl Solution ◽  
Electrochemical Impedance Spectra ◽  
Alloy Matrix ◽  
Content Type

Purpose – This paper aims to report a study of the influence of tungsten carbide (WC) nanoparticles on corrosion resistance properties of electroless nickel–phosphorus (Ni–P) coatings in NaCl solution. Design/methodology/approach – The morphology of Ni–P–WC nanocomposite coatings was observed by scanning electron microscopy (SEM). The anodic polarization curves, electrochemical impedance spectra (EIS) and weight loss measurements were used to study the corrosion resistance properties of Ni–P–WC nanocomposite coatings in NaCl solution. Findings – The WC nanoparticles content in the coatings increased with the increase of its concentration in the bath, and the WC nanoparticles are uniformly distributed in Ni–P alloy matrix. The results showed that the incorporation of WC nanoparticles elevated the corrosion resistance properties of Ni–P alloy matrix. Originality/value – This study shows that the corrosion resistance was improved by the addition of WC nanoparticles to the Ni–P alloy matrix.

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