Effects of alkaline zinc bath formulations on electrochemical corrosion behavior of electrogalvanized coatings

CORROSION ◽  
10.5006/3760 ◽  
2021 ◽  
Author(s):  
Thanyalux Wanotayan ◽  
Tongjai Chookajorn ◽  
Sirikarn Sattawitchayapit ◽  
Piya Khamsuk ◽  
Kanokwan Saengkiettiyut ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Surface Morphology ◽  
Electrochemical Impedance ◽  
Texture Coefficient ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Plating Bath ◽  
Zinc Plating ◽  
Electrochemical Corrosion Behavior ◽  
Zinc Coatings

The effects of alkaline non-cyanide zinc plating bath formulation on the plating characteristics and deposit properties are investigated. Scanning electron microscope and X-ray diffractometer are used to study the surface morphology and texture of the zinc deposits respectively. Uniform and compact coatings with a dominant (110) texture are obtained for all of the bath formulations. Nevertheless, significant differences in surface morphology and relative preferences for the (110) and (100) planes were found to result from the concentrations of zinc and sodium hydroxide in the bath. Electrochemical impedance spectroscopy and potentiodynamic polarization scan were employed to evaluate the corrosion resistance. The coatings with a moderate Zn (8-11 g/L) and controlled NaOH (120 g/L) contents show good corrosion resistance, with the corrosion current and corrosion rate being the lowest at 8 g/L of Zn and 120 g/L of NaOH. The ratio of texture coefficient, morphology, and compressive residual stress from different bath composition contribute to the corrosion resistant property. The findings from this work should provide useful information of electrogalvanized zinc coatings with enhanced corrosion resistance.

Structure and Corrosion Resistance of Iron Coatings Containing Silicon Powders

2011 ◽  
Vol 399-401 ◽  
pp. 1926-1931 ◽  
Author(s):  
Yi Wang ◽  
Gang Chen ◽  
Wei Dong Liu ◽  
Qiong Yu Zhou ◽  
Qing Dong Zhong
Keyword(s):  
Corrosion Resistance ◽  
Phase Composition ◽  
Thermal Treatment ◽  
Surface Morphology ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Active Surface ◽  
Active Surface Area ◽  
Two Phase ◽  
Electrochemical Corrosion Resistance

Fe + Si coatings were prepared by iron deposition from a bath containing a suspension of silicon powders. These coatings were obtained at galvanostatic conditions, at the current density of jdep=−0.020 A cm−2 and at the temperature of 338 K. For determination of the influence of phase composition and surface morphology of these coatings on changes in the corrosion resistance, these coatings were modified in an argon atmosphere by thermal treatment at 873 K for 2h. A scanning electron microscope was used for surface morphology characterization of the coatings. The chemical composition of the coatings was determined by EDS and phase composition investigations were conducted by X-ray diffraction. It was found that the as-deposited coatings consist of a two-phase structure, i.e., iron and silicon. The phase composition for the Fe + Si coatings after thermal treatment is markedly different. The main peaks corresponding to Fe and Si coexist with the new phases: FeSi. Electrochemical corrosion resistance investigations were carried out in 3.5wt% NaCl, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found that the Fe + Si coatings after thermal treatment are more corrosion resistant in 3.5wt% NaCl solution than the as-deposited coatings. The reasons for this are a reduction in the amount of free iron and silicon, the presence of new phases (in particular silicides), and a decrease of the active surface area of the coatings after thermal treatment.

scholarly journals Effect of Cu Addition on the Electrochemical Corrosion Performance of Ni3Al in 1.0 M H2SO4

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
J. Porcayo-Calderon ◽  
R. A. Rodriguez-Diaz ◽  
E. Porcayo-Palafox ◽  
J. Colin ◽  
A. Molina-Ocampo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Intermetallic Alloy ◽  
Intermetallic Alloys ◽  
Corrosion Performance ◽  
Linear Polarization Resistance ◽  
Electrochemical Corrosion Behavior

The effect of Cu addition on the electrochemical corrosion behavior of Ni3Al intermetallic alloy was investigated by potentiodynamic polarization, open-circuit potential, linear polarization resistance, and electrochemical impedance spectroscopy in 1.0 M H2SO4solution. Performance of the pure elements (Cu, Ni, and Al) was also evaluated. In general, Cu addition improved the corrosion resistance of Ni3Al. Electrochemical measurements show that corrosion resistance of Ni3Al-1Cu alloy is lower than that of other intermetallic alloys and pure elements (Ni, Cu, and Al) in 1.0 M H2SO4solution at 25°C. Surface analysis showed that the Ni3Al alloys are attacked mainly through the dendritic phases, and Cu addition suppresses the density of dendritic phases.

Effect of High-Intensity Pulsed Ion Beam Irradiation on the Electrochemical Corrosion Behavior of AZ31 Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 571-574
Author(s):  
Peng Li
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Current Density ◽  
Ion Beam ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Open Circuit ◽  
Electrochemical Corrosion Behavior ◽  
Shot Number

HIPIB irradiation experiment is carried out at a specific ion current density of 1.1 J/cm2 with shot number from one to ten in order to explore the effect of shot number on electrochemical corrosion behavior of magnesium alloy. Surface morphologies, microstructure and corrosion resistance of the irradiated samples are examined by scanning electron microscopy (SEM), transmission electron microscope (TEM) and potentiodynamic polarization technique, respectively. It is found that HIPIB irradiation leads to the increase in open circuit potential, corrosion potential and breakdown potential, and the decrease in the corrosion current density and the corrosion rate as compared to the original sample. The improved corrosion resistance is mainly attributed to the grain refinement and surface purification induced by HIPIB irradiation.

scholarly journals The Microstructure Evolution and Electrochemical Corrosion Behavior of 7A46 Aluminum Alloy in Different Quenching Conditions

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 477
Author(s):  
Yaru Liu ◽  
Lu Xing ◽  
Qing Zeng ◽  
Qinglin Pan ◽  
Sheng Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Aged Alloy ◽  
Quench Sensitivity ◽  
Free Zone ◽  
The Matrix ◽  
Electrochemical Corrosion Behavior

The quenching condition of aluminum alloy can affect the mechanical property and corrosion resistance of the profile. This paper is aimed at the low quench sensitivity of aluminum alloys. Scanning electron microscopy and transmission electron microscopy were used to analyze precipitate behaviors of the 7A46 aluminum alloy under different isothermal cooling conditions and microstructure evolutions of quench-induced precipitations. The effect of the different isothermal time on the corrosion resistance of the alloy, and the relationship between microstructure and corrosion resistance after quenching were revealed through electrochemical impedance spectroscopy and potentiodynamic polarization tests. Results show that corrosion sensitivity of the quenching-aged alloy is much higher than that of the double-aged (DA) alloy, and the corrosion resistance of the quenched alloy decreases firstly and then increases. Due to the high density of the matrix precipitates, the increased content of the impurity element, the discontinuity of the grain boundary precipitates and the widening of the precipitates free zone, the most serious degree of corrosion performance among the quenched alloys is 295 °C at 800 s, and the self-corrosion potential and self-current density is −0.919 V and 2.371 μA/cm2, respectively.

Thermal Parameters Influence Assessed by Electrochemical Impedance Spectroscopy on a Ni50Ti48Nb2 Shape Memory Alloy

2018 ◽  
Vol 69 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Ioana Arina Gherghescu ◽  
Daniela Ionita ◽  
Sorin Ciuca ◽  
Ruxandra Elena Dumitrescu
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Transformation Temperatures ◽  
Electrochemical Corrosion Behavior

This paper presents some electrochemical impedance spectroscopy research results concerning the corrosion resistance of a shape memory Ni50Ti48Nb2 alloy. This one was previously studied by SEM and DSC [1,2] but some new research features had to be made clear in order to be able to explain its electrochemical corrosion behavior. The chemical composition Ni50Ti48Nb2 was chosen in order to obtain a shape memory alloy having a wider hysteresis than equiatomic NiTi, for the purpose of achieving a better thermomechanical stability. Cryogenic applications are aimed. After processing the cast ingot, two samples, S1 and S2, were further annealed at 800�C/12 h and, respectively, at 900�C/12h. Scanning electron micrographs together with the chemical elements mapping results were obtained. They were related to the previous results concerning the informations on the structure of the different phases found in this NiTiNb alloy: austenite, martensite and secondary phases, as well as some primary compounds [1,2]. Considering the size and shape of the complex precipitate particles of NiTiNb in the two differently heat treated samples, these were found responsible for some changes in the transformation temperatures [3] but the electrochemical corrosion behavior of the alloy seems to be influenced to a lesser extent by the heat treatments. Both samples exhibit good values of corrosion resistance, however S2 shows better values than S1. Thus lower transformation temperatures and a slightly better corrosion resistance make the Ni50Ti48Nb2 alloy annealed at 900�C/12h subsequently submitted to thermal cycling to be the right choice for producing couplings in the cryogenic industry.

The Preparation of Coatings with Codepositon Plating on A3 Steel and its Corrosion Resistance

2010 ◽  
Vol 150-151 ◽  
pp. 1034-1038
Author(s):  
Shang Dong Chen ◽  
Ting Sun ◽  
Hong Nian
Keyword(s):  
Corrosion Resistance ◽  
Polarization Resistance ◽  
Polarization Effect ◽  
Corrosion Potential ◽  
Steel Substrate ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Plain Carbon Steel ◽  
Cathode Polarization ◽  
Electrochemical Corrosion Behavior

A new method for preparation of coatings with codeposition plating on the ordinary A3 steel and heat treatment later. Research the coatings on electrochemical corrosion behavior variation in Q-sun. Results show that corrosion potential shuffle, corrosion current density reduced nearly two number magnitudes value, polarization resistance increased, the cathode polarization effect enhanced obviously in polarization curves, and self-corrosion current reduced, impedance increased twenty times in alternating current impedance atlas than A3 steel substrate without coatings. It was indicated that the coating improve effectively the corrosion resistance of plain carbon steel.

scholarly journals Effect of Ca Addition on Corrosion Behavior of Wrought AM60 Magnesium Alloy in Alkaline Solutions

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1172
Author(s):  
Polina Metalnikov ◽  
Guy Ben-Hamu ◽  
Kwang Seon Shin ◽  
Amir Eliezer
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Fuel Efficiency ◽  
Electrochemical Corrosion ◽  
Alkaline Solutions ◽  
Kelvin Probe ◽  
Ca Addition ◽  
Electrochemical Corrosion Behavior

Magnesium (Mg) alloys possess the lowest density among structural materials, and their application in the automotive and aircraft industries might enhance fuel efficiency. The mechanical properties can be improved by the addition of alloying elements. However, since Mg and its alloys are very susceptible to corrosion degradation, it is important to study the effect of these elements on the alloys’ corrosion behavior. In this study, 1 wt% of calcium (Ca) was added to wrought AM60 Mg alloy, and the electrochemical corrosion behavior of the alloys in alkaline solutions with and without Cl− ions was compared. The corrosion behavior was investigated by means of immersion tests, gravimetric measurements and potentiodynamic polarization (PDP); the characteristics of the oxide layer were studied by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The addition of Ca resulted in precipitation of the ternary aluminum-rich (Mg-Al)2Ca phase. Scanning Kelvin probe force microscope (SKPFM) identified that this phase has a cathodic behavior relative to the α-Mg matrix; hence it can serve as additional sites for initiation of pitting corrosion. As a result, the corrosion resistance of wrought AM60 alloy with 1 wt% Ca addition deteriorated in a NaCl solution. However, in the absence of Cl− ions, alloying with Ca improves the corrosion resistance of wrought AM60 alloy due to the stabilization of the corrosion products layer. The effect of long-period immersion time on the corrosion behavior and alloy oxidation is discussed.

Electrochemical Corrosion Behavior of Iron Aluminides in Sulfuric Acid

2020 ◽  
Vol 1012 ◽  
pp. 395-400
Author(s):  
Pedro Paiva Brito ◽  
Carlos Trivellato de Carvalho Filho ◽  
Gabriela de Andrade Oliveira
Keyword(s):  
Current Density ◽  
Corrosion Current Density ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Passive Behavior ◽  
Corrosion Evaluation ◽  
Electrochemical Corrosion Behavior ◽  
Work Samples ◽  
Passive Current

In the present work, samples of a binary intermetallic alloy (Fe3Al) with 26at.%Al were submitted to electrochemical corrosion evaluation in a 0.5M H2SO4 solution containing naturally dissolved oxygen. The corrosion resistance was evaluated by applying linear polarization, electrochemical impedance spectroscopy and potentiodynamic polarization at 22 and 35°C. The results obtained revealed that in both conditions the material exhibits active-passive behavior. Heating to 35°C did not alter the passivity characteristics of the alloy (passivation range and passive current density), but elevated the corrosion current density and the critical current density. The polarization resistance of the samples was also decreased with temperature, following the trend observed for the corrosion current density.

scholarly journals Effects of Process Parameters and CrCl3 Concentration on the Structure, Surface Morphology, Composition and Corrosion Resistance of Electrodeposited NiCrP Amorphous Alloy Coatings

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 795
Author(s):  
Jingjing Xiao ◽  
Jinku Yu ◽  
Fuyu Guo ◽  
Qi Qiao ◽  
Haibo Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Amorphous Alloy ◽  
Surface Morphology ◽  
Process Parameters ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Sodium Dodecyl ◽  
Alloy Coating ◽  
Corrosion Current ◽  
Structure Surface

Herein, NiCrP amorphous alloy coatings were prepared on copper substrates by electrodeposition. The aim of this paper is to replace Cr6+ with Cr3+ to prepare NiCrP amorphous alloy coating, which can reduce environmental pollution. By studying the influence of pH, temperature (T), current density (DK), and CrCl3 concentration on the structure, surface morphology, composition, and corrosion resistance of the alloy coatings, the optimum bath formulation and process parameters were determined as follows: 25 g·L−1 NiSO4·6H2O, 100 g·L−1 CrCl3·6H2O, 20 g·L−1 NaH2PO2·H2O, 80 g·L−1 Na3C6H5O7·2H2O (sodium citrate), 40 g·L−1 H3BO3, 50 g·L−1 NH4Cl, 1 g·L−1 KF, 5 g·L−1 C7H5O3NS (saccharin), 0.05 g·L−1 C12H25SO4Na (sodium dodecyl sulfate), and 40 mL·L−1 HCOOH and T: 30 °C, DK: 15 A·dm−2, and pH: 3.5, respectively. NiCrP amorphous alloy coatings with high corrosion resistance were prepared under the abovementioned conditions. The crystal cells of the coating surface are uniform and fine. The corrosion resistance of the NiCrP amorphous alloy coatings was characterized by polarization curves, electrochemical impedance spectroscopy, and an immersion corrosion test and compared with that of the NiP amorphous alloy coating. The results show that Ni91.9P8.1 and Ni83.5Cr8.3P8.2 corrosion potential and corrosion current density are −0.68, −0.44 V, and 36, 7 μA·cm−2 in 3.5 wt.% NaCl, respectively. With Ni91.9P8.1 and Ni83.5Cr8.3P8.2, the maximum weight loss is 61.67 and 15.42 mg·dm−2 in a 1 mol·L−1 HCl, respectively. The corrosion resistance of the NiCrP amorphous alloy coatings in 3.5 wt.% NaCl and 1 mol·L−1 HCl solutions is better than that of the NiP alloy coating.

Electrochemical corrosion behavior of HVOF sprayed WC–12Co coating on H13 hot work mould steel

2019 ◽  
Vol 66 (6) ◽  
pp. 827-834
Author(s):  
Kong Weicheng ◽  
Shen Hui ◽  
Gao Jiaxu ◽  
Wu Jie ◽  
Lu Yuling
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Curvature Radius ◽  
Nacl Solution ◽  
Content Type ◽  
Capacitance Curve ◽  
Electrochemical Corrosion Behavior ◽  
Corrosion Behaviors

Purpose This study aims to investigate the electrochemical corrosion performance of high velocity oxygen fuel (HVOF) sprayed WC–12Co coating in 3.5 Wt.% NaCl solution, which provided a guiding significance on the corrosion resistance of H13 hot work mould steel. Design/methodology/approach A WC–12Co coating was fabricated on H13 hot work mould steel using a HVOF, and the electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution was measured using open circuit potential (OCP), potentiodynamic polarization curve (PPC) and electrochemical impedance spectroscopy (EIS) tests. Findings The OCP and PPC of WC–12Co coating positively shift than those of substrate, its corrosion tendency and corrosion rate decrease to enhance its corrosion resistance. The curvature radius of capacitance curve on the WC–12Co coating is larger than that on the substrate, and the impedance and polarization resistance of WC–12Co coating increase faster than those of substrate, which reduces the corrosion process. Originality/value The electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution is first measured using OCP, PPC and EIS tests, which improve the electrochemical corrosion resistance of H13 hot work mould steel.

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