Pore blocking characteristics of corrosion products formed on Aluminum coating produced by arc thermal metal spray process in 3.5 wt.% NaCl solution

2016 ◽  
Vol 113 ◽  
pp. 905-916 ◽  
Author(s):  
Han-Seung Lee ◽  
Jitendra Kumar Singh ◽  
Jang Hyun Park
Keyword(s):  
Aluminum Coating ◽  
Corrosion Products ◽  
Nacl Solution ◽  
Spray Process ◽  
Pore Blocking ◽  
Metal Spray

scholarly journals Effect of YAl2 Particles on the Corrosion Behavior of Mg–Li Matrix Composite in NaCl Solution

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 549 ◽  
Author(s):  
Zihan Chen ◽  
Chonggao Bao ◽  
Guoqing Wu ◽  
Yongxin Jian ◽  
Li Zhang
Keyword(s):  
Corrosion Resistance ◽  
Intermetallic Compound ◽  
Corrosion Behavior ◽  
Matrix Composite ◽  
Surface Film ◽  
Interface Layer ◽  
Corrosion Products ◽  
Nacl Solution ◽  
The Stability ◽  
Main Factor

The strength of Mg–Li alloy is greatly improved by the composite strengthening of intermetallic compound YAl2 particles, but the low corrosion resistance of Mg–Li alloy is still the main factor that restricts the application of the alloy and its composites. In this paper, the effect of YAl2 particles on the corrosion behavior of Mg–Li alloy was systematically investigated. The results showed that the corrosion resistance of YAl2p/LA143 composite could be significantly improved, accounting for the formation of a transitional interface layer by adding YAl2 particles. The diffusion of yttrium and aluminum atoms from YAl2 particulates improved the stability of the surface film and enhanced the adhesion between the corrosion products and the substrate, which hindered further expansion of pitting.

Study on Corrosion Process of Al-Mg Coatings Based on Electrochemical Impedance Spectroscopy

2017 ◽  
Vol 744 ◽  
pp. 380-384
Author(s):  
Hui Tong ◽  
Wen Li Han ◽  
Zhong Ping Xu ◽  
Yan Jun Zhang ◽  
Zhu Lin ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Corrosion Process ◽  
Corrosion Products ◽  
Passive Films ◽  
Nacl Solution ◽  
Electrochemical Testing ◽  
Immersion Corrosion

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.

scholarly journals Deposition of Coating to Protect Waste Water Reservoir in Acidic Solution by Arc Thermal Spray Process

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Han-Seung Lee ◽  
Jin-ho Park ◽  
Jitendra Kumar Singh ◽  
Mohamed A. Ismail
Keyword(s):  
Thermal Spray ◽  
Electrochemical Impedance ◽  
Water Reservoir ◽  
Corrosion Products ◽  
304 Stainless Steel ◽  
Metallic Surface ◽  
Stable Phase ◽  
Transfer Resistance ◽  
Thermal Spray Process ◽  
Spray Process

The corrosion characteristics of 304 stainless steel (SS) and titanium (Ti) coatings deposited by the arc thermal spray process in pH 4 solution were assessed. The Ti-sprayed coating exhibits uniform, less porous, and adherent coating morphology compared to the SS-sprayed coating. The electrochemical study, that is, electrochemical impedance spectroscopy (EIS), revealed that as exposure periods to solution were increased, the polarization resistance (Rp) decreased and the charge transfer resistance (Rct) increased owing to corrosion of the metallic surface and simultaneously at the same time the deposition of oxide films/corrosion on the SS-sprayed surface, while Ti coating transformed unstable oxides into the stable phase. Potentiodynamic studies confirmed that both sprayed coatings exhibited passive tendency attributed due to the deposition of corrosion products on SS samples, whereas the Ti-sprayed sample formed passive oxide films. The Ti coating reduced the corrosion rate by more than six times compared to the SS coating after 312 h of exposure to sulfuric acid- (H2SO4-) contaminated water solution, that is, pH 4. Scanning electron microscope (SEM) results confirmed the uniform and globular morphology of the passive film on the Ti coating resulting in reduced corrosion. On the other hand, the corrosion products formed on SS-sprayed coating exhibit micropores with a net-like microstructure. X-ray diffraction (XRD) revealed the presence of the composite oxide film on Ti-sprayed samples and lepidocrocite (γ-FeOOH) on the SS-coated surface. The transformation of TiO and Ti3O into TiO2 (rutile and anatase) and Ti3O5 after 312 h of exposure to H2SO4 acid reveals the improved corrosion resistance properties of Ti-sprayed coating.

Ice-Formation Expansion of Salt Solution and its Effect on Frost Damage of Concrete

2014 ◽  
Vol 633 ◽  
pp. 281-285
Author(s):  
Zu Quan Jin ◽  
Tie Jun Zhao ◽  
Song Gao ◽  
Su Yuan Zhang
Keyword(s):  
Frost Damage ◽  
Corrosion Products ◽  
Ice Formation ◽  
Chloride Salt ◽  
Nacl Solution ◽  
Damage Degree ◽  
Salt Corrosion ◽  
Deterioration Mechanism ◽  
Composite Solution ◽  
Air Entrained Concrete

In order to explain the deterioration mechanism of air entrained concrete subjected to freeze-thaw cycles in water, NaCl, Na2SO4 and composite solution, The damage of concrete and ice-formation expansion of salt corrosion solution are tested. The experimental results show that the damage degree of concrete under salt frost is NaCl solution>composite solution>water>Na2SO4 solution. Considering the chloride penetrated into concrete and following 2nd Fick’s Law, the ice-formation expansion resulted by NaCl solution in surface layer of concrete is higher than that in inner, and the expansion stress at outer layer is 1.73 times of that at inner layer according to the proposed function. The expansion stress difference between the internal and external layer causes spalling damage of concrete in chloride salt frost. The ice-formation expansion of Na2SO4 solution increases with its raising concentration and it is higher than that of NaCl solution at the same temperature. However, the corrosion products are ettringite and gypsum after sulfate salt frost, and the volume of solid corrosion products is barely change, or even reducible.

Investigation on the Corrosion Behavior of Zn27Al3Cu Alloy in 3.5 wt.% NaCl Solution

2012 ◽  
Vol 482-484 ◽  
pp. 537-540
Author(s):  
Yong Tan ◽  
Cheng Gang Hao ◽  
De Zhi Li ◽  
Zhi Liu Hu ◽  
Jian Min Zeng
Keyword(s):  
Weight Loss ◽  
Corrosion Behavior ◽  
Corrosion Products ◽  
Corrosion Mechanism ◽  
Attenuation Relationship ◽  
Nacl Solution ◽  
Cu Alloy ◽  
Weight Loss Method ◽  
Loss Method ◽  
Scanning Electron

The corrosion behavior of Zn27Al3Cu in 3.5 Wt.% NaCl solution is investigated through weight loss method. The morphology of corrosion products were observed and analyzed with optical microscopy (OM), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The experimental results indicate that weight loss of the alloy with time follows the exponential attenuation relationship. Corrosion mechanism of Zn27Al3Cu alloy are intergranular corrosion and preferential corrosion in 3.5 Wt.% NaCl solution, the main corrosion products are compound oxide and chloride.

scholarly journals Corrosion Resistance Properties of Aluminum Coating Applied by Arc Thermal Metal Spray in SAE J2334 Solution with Exposure Periods

Metals ◽  
2016 ◽  
Vol 6 (3) ◽  
pp. 55 ◽  
Author(s):  
Han-Seung Lee ◽  
Jitendra Singh ◽  
Mohamed Ismail ◽  
Chinmoy Bhattacharya
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Coating ◽  
Metal Spray

The Corrosion Behaviors of the Cerium Conversion Coatings on the Zinc Coating in a 5 % NaCl Solution

2017 ◽  
Vol 36 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Jianghong Zhang ◽  
Binfang Meng ◽  
Xinying Wang ◽  
Wei Li
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Zinc Coating ◽  
Conversion Coating ◽  
Corrosion Products ◽  
Nacl Solution ◽  
Cerium Content ◽  
Electrochemical Parameters ◽  
Corrosion Behaviors ◽  
The Impact

AbstractThe present paper investigated the impact of cerium on the corrosion resistance of zinc coating in a 5 % NaCl solution. Electrochemistry was used to measure the electrochemical parameters to compare the corrosion resistance of the zinc coating with that of the cerium conversion coating on the galvanized layer. SEM/EDS and XRD were adopted to analyze the appearance and phases of corrosion products of the cerium conversion coating and to probe the impact of cerium on the corrosion behavior of zinc coating in the Cl–media. The results showed that the cerium conversion coating formed on the zinc coating increased the zinc’s corrosion resistance effectively, conversion coating with lower cerium content protected the substrate poorly, resulting in easy erosion of the zinc coating in the Cl–media. The corrosion products mainly consist of complexes, such as Zn(OH)xClyand Ce(OH)xCly.

Study on Corrosion Behaviors of Epoxy Aluminum Coating Immersed in 3.5%NaCl Solution

2014 ◽  
Vol 912-914 ◽  
pp. 338-341 ◽  
Author(s):  
Rui Yan ◽  
Ting Liang ◽  
Hong Chun Ren ◽  
Jin Gu ◽  
Zhuang Zhou Ji
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Osmotic Pressure ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Aluminum Coating ◽  
Nacl Solution ◽  
Metal Interface ◽  
Electrochemical Corrosion Behavior ◽  
Corrosion Behaviors

Electrochemical corrosion behavior of epoxy aluminum coating immersed in 3.5%NaCl solution was investigated using electrochemical impedance spectroscopy (EIS). SEM was also used to analyze the surface images of coating, and the failure mechanism was discussed as well. The experimental results showed that corrosive species can penetrate into coatings and reach the coating/substrate interface promptly, causing the decrease of electro-resistance and the beginning of electrochemical corrosion at the coatings/metal interface. The coating was compact and continuous at beginning, while the blisters and cavities appeared after corrosion, which were formed osmotic pressure created by corrosion species penetration.

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