Effects of Anions on Corrosion Behavior of Ni-Cu-P Coatings

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.

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.


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.


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.


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.


2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760002 ◽  
Author(s):  
P. E. Saranya ◽  
S. Selladurai

Flower-shaped self-assembled zinc oxide (ZnO) nanoflakes were successfully synthesized via a temperature-controlled hydrothermal method. The crystallinity and phase formation of the compound were determined from powder X-ray diffraction (PXRD) result. Surface morphology investigations reveal the self-assembled ZnO nanoflakes to form a spherical flower-like structure. In addition, the particle size was determined from high-resolution transmission electron microscope measurement as 18[Formula: see text]nm which is in accord with XRD and UV results. X-ray photo electron spectroscopy studies reveal the chemical composition and oxidation state of the ZnO nanoparticle. The specific surface area was calculated, and mesoporous nature was confirmed using Brunauer–Emmett–Teller analysis. Results support the superior interaction between the electrode and electrolyte ions through surface pores. Capacitive performance of the ZnO electrode material was determined using cyclic voltammetry and galvanostatic charge/discharge studies, and a maximum specific capacitance of 322[Formula: see text]F/g was obtained at 5[Formula: see text]mV/sec. Electrochemical impedance spectrum reveals the materials fast charge transfer kinetics.


Author(s):  
Hayette Faid

AbstractIn this work, Zn-Ni alloys have been deposited on steel from sulfate bath, by electrodeposition method. The effect of Zn content on deposits properties was studied by cyclic voltammetry (CV), chronoaperometry (CA), linear stripping voltammetry (ALSV) and diffraction (XRD) and scanning electronic microscopy (SEM). The corrosion behavior in 3.5 wt. NaCl solution was examined using anodic polarization test and electrochemical impedance spectroscopy. X-ray diffraction of show that Zn-Ni alloys structure is composed of δ phase and γ phase, which increase with the decrease of Zn content in deposits. Results show that deposits obtained from bath less Zn2+ concentration exhibited better corrosion resistance.


Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 758 ◽  
Author(s):  
Yang ◽  
Zhang ◽  
Wang ◽  
Wang ◽  
Chen ◽  
...  

Pure Zn and Zn–ERGO composite coatings were prepared by direct current electrodeposition on 304 stainless steel. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS), and laser Raman spectroscopy (Raman). Results obtained have shown that the concentration of GO sheets in zinc sulfate electrolyte has an important effect on the preferred crystal orientation and the surface morphology of Zn–ERGO composite coatings. A study of the corrosion behavior of the coatings by Tafel polarization and electrochemical impedance spectroscopic (EIS) methods leads to the conclusion that the Zn-1.0 g/L ERGO composite coating possesses the best corrosion resistance compared to the pure Zn coating and other composite coatings in this study.


Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 636 ◽  
Author(s):  
Xu ◽  
Wang ◽  
Chen ◽  
Qiao ◽  
Zhang ◽  
...  

The effect of rare earth oxides on the microstructure and corrosion behavior of laser-cladding coating on 316L stainless steel was investigated using hardness measurements, a polarization curve, electrochemical impedance spectroscopy (EIS), a salt spray test, X-ray diffraction, optical microscopy, and scanning electron microscopy (SEM). The results showed that the modification of rare earth oxides on the laser-cladding layer caused minor changes to its composition but refined the grains, leading to an increase in hardness. Electrochemical and salt spray studies indicated that the corrosion resistance of the 316L stainless steel could be improved by laser cladding, especially when rare earth oxides (i.e., CeO2 and La2O3) were added as a modifier.


2014 ◽  
Vol 61 (5) ◽  
pp. 319-327 ◽  
Author(s):  
Mohamed Gobara ◽  
Mohamed Shamekh

Purpose – This paper aims to study both the mechanical properties and the corrosion behavior of the synthesized in situ (TiC-TiB2) particulates/AZ91 magnesium matrix composite and compare the results with that of the conventional AZ91D alloy. Design/methodology/approach – Scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were used to study the surface morphology and crystalline structure. Mechanical compression tests were used to investigate the mechanical performance according to ASTM E9-89a. The corrosion behavior of the synthesized magnesium alloy was examined using both electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques in dilute Harrison solutions. Findings – The microstructure of the Mg composite showed a uniform distribution of reinforcing phases. Also, the reinforcing phases were formed without residual intermediate phases. The addition of titanium and boron carbides not only enhanced the mechanical properties of the matrix but also improve its corrosion behavior. Originality/value – This is the first time that magnesium matrix composite has been to synthesized with TiC and TiB2 particulates starting from starting from Ti and B carbides powder without adding aluminium using practical and low-cost technique (in situ reactive infiltration technique). This paper studies the corrosion behavior of synthesized Mg matrix in dilute Harrison solution and compares the results with that of conventional AZ91D.


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.


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