scholarly journals Corrosion resistance of graphene/waterborne epoxy composite coatings in CO 2 -satarated NaCl solution

2020 ◽  
Vol 7 (5) ◽  
pp. 191943
Author(s):  
Hao Xu ◽  
Haijun Hu ◽  
Hongmei Wang ◽  
Yongjun Li ◽  
Yun Li
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Epoxy Composite ◽  
Composite Coatings ◽  
Nacl Solution ◽  
Transmission Electron ◽  
Waterborne Epoxy ◽  
Lower Corrosion Rate

This study investigated the corrosion resistance of graphene/waterborne epoxy composite coatings in CO 2 -satarated NaCl solution. The coatings were prepared by dispersing graphene in waterborne epoxy with the addition of carboxymethylcellulose sodium. The structure and composition of the coatings were characterized by scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared and Raman spectroscopies. The corrosion resistance of the composite coatings was investigated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy. Composite coatings with more uniform surfaces and far fewer defects than blank waterborne epoxy coatings were obtained on 1020 steel. The 0.5 wt% graphene/waterborne epoxy composite coating exhibited a much lower corrosion rate and provided better water resistance properties and long-term protection than those of the blank epoxy coating in CO 2 -satarated NaCl solution.

Study of Corrosion Behavior of Conventional and Nanostructured WC-Co HVOF Sprayed Coats

2010 ◽  
Vol 64 ◽  
pp. 13-18 ◽  
Author(s):  
Shahin Khameneh Asl ◽  
Mohammad Reza Saghi Beyragh ◽  
Mahdi Ghassemi Kakroudi
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Heat Treating ◽  
Crystalline Phases ◽  
Chemical Test ◽  
Transmission Electron ◽  
Hvof Spray ◽  
Wear And Corrosion Resistance

Interest in nanomaterials has increased in recent years. This is due to the potential of size reduction to nanometric scale to provide properties of materials such as hardness, toughness, wear, and corrosion resistance. The current study is focused on WC-Co cermet coats, materials that are extensively used in applications requiring wear resistance. In this work, WC-17Co powder was thermally sprayed onto mild steel using High Velocity Oxy Fuel (HVOF) spray technique. The nanostructured specimen was produced from sprayed sample by heat-treating at 1100°C in a vacuum chamber. Their structures were studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Polarization and electrochemical impedance spectroscopy (EIS) tests were performed on the both types of coated samples in 3.5% NaCl solution. The amorphous phase in WC-17Co coating was transformed to crystalline phases by heat treatment at high temperatures. The heat treatment of these coatings at high temperature also resulted in partially dissolution of WC particles and formation of new crystalline phases. Generation of these phases produced the nanostructured coating with better mechanical properties. Comparative electro chemical test results showed that, the heat treatment could improve corrosion resistance of the nanostructured WC-17Co coat than the as sprayed coats.

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.

Effect of KI on the Corrosion Resistance of Ni-P Electroless Plating Coating

2014 ◽  
Vol 633-634 ◽  
pp. 817-820
Author(s):  
Ping Liang ◽  
Yun Xia Zhang ◽  
Yan Hua Shi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Phosphorus Content ◽  
Electrochemical Impedance ◽  
Nacl Solution ◽  
Electroless Coating ◽  
Scanning Electron

To improve the corrosion resistance of Ni-P electroless coating, the KI was added in the electroless solution. The surface micrograph was observed using scanning electron microscopy (SEM), and the corrosion resistance of Ni-P coatings in 3.5%NaCl solution was examined by polarization curves and electrochemical impedance spectroscopy (EIS). The experimental results showed that KI reduced the amount of defects and the size of crystal grain of Ni-P coating, and the surface of Ni-P coating became more homogenous, smoother and compact by KI. In addition, the phosphorus content of Ni-P coating was increased by KI. These factors increased the ability to corrosion protection of Ni-P coating.

Characterization of Ni-P and Ni-P-Al2O3 Heat Treated Layers

2017 ◽  
Vol 1143 ◽  
pp. 26-31
Author(s):  
Lucica Balint ◽  
Gina Genoveva Istrate
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Corrosion Resistance ◽  
Composite Coatings ◽  
Treatment Temperature ◽  
Initial State ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Before And After

Research has shown the relationship among hardness, usage and corrosion resistance Ni-P-Al2O3 composite coatings on steel support heat treated. The electroless strips were heat treated at 200°C, 300°C, 400°C, 500°C and 600°C. Further studies on corrosion, hardness and usage revealed changes in properties, compared to the initial state, both on the strips coated with Ni-P and the ones coated with Ni-P-Al2O3 composite. The samples have been studied before and after the heat treatment via Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Analysis (EDX) and X-Ray Diffraction (XRD). The results show that untreated Ni-P layers exhibit strong corrosion resistance, while hardness and usage increase with heat treatment temperature, with a peak at 400 °C. Using suspended particles co-deposition, led to new types of layers, some with excellent hardness and usage properties. Corrosion resistance increase with heat treatment. Coating layers can be adjusted to the desired characteristics, by selecting proper parameters for the expected specific results.

Investigation of corrosion behavior on plastically deformed aa 7075 t651 by shot peening process

2021 ◽  
Author(s):  
Abeens M ◽  
R Murugananthan
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Dislocation Density ◽  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
X Ray ◽  
Transmission Electron ◽  
Aa 7075 ◽  
Micro Structures

Abstract As AA 7075 T651 comprehensively is used in the marine naval vessels, the factor of corrosion performance always plays a significant role. In this work, an investigation is carried out to study the effect of corrosion behaviour of shot peened AA 7075 T651 in 3.5% solution. From the potentiodynamic polarization study, a 27.72% decrease is ascertained in the Icorr in shot peened specimen in correlation to unpeened aluminium alloy. A drop in Icorr from 1.883 to 1.480 mA/cm2 in shot peened specimen, indicates enhanced pitting corrosion resistance. An electrochemical impedance spectroscopy reveals a surge in the oxide layer formation on the peened surface aiding the drop in corrosion rate. Resistance to pit formations and improvement in oxygen deposition in the peened specimen is observed availing a Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray analysis (EDX). The micro structures of the peened and unpeened specimen are captured using optical microscopy and Transmission electron microscopy (TEM). Micro-strain, dislocation density is also calculated from the X- ray diffraction analysis (XRD), in which grain size reduces by 28.07%, dislocation density surges by 38.65% and micro strain increases by 21.95% in peened specimen in correlation to unpeened AA 7075 T651, resulting in a surge in corrosion resistance by 27.92% in the peened specimen in correlation to unpeened aluminium alloy.

scholarly journals APTES Modification of Molybdenum Disulfide to Improve the Corrosion Resistance of Waterborne Epoxy Coating

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 178
Author(s):  
Yang Liu ◽  
Shihong Zhang ◽  
Yi He ◽  
Chunlin Chen ◽  
Chen Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Molybdenum Disulfide ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Crosslinking Density ◽  
Anticorrosion Property ◽  
Nacl Solution ◽  
Simple Modification ◽  
N80 Steel ◽  
Waterborne Epoxy

MoS2 has been regarded as a promising addition for the preparation of epoxy-based coatings with high anticorrosion ability. However, its dispersion and compatibility remain significant challenges. In the present work, an organic thin layer was well coated on lamellar molybdenum disulfide (MoS2) via a simple modification of 3-aminopropyltriethoxysilane (APTES). The modification of hydrolyzing APTES on lamellar MoS2 effectively improved the dispersity of MoS2 in water-borne epoxy (WEP) and successfully enhanced the compatibility and crosslinking density of MoS2 with WEP. The influence of introducing MoS2-APTES into WEP coating on anticorrosion property for N80 steel was tested by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and salt spray test. The results exhibited that the |Z|0.01Hz value of MoS2-APTES/WEP still reached 3.647 × 107 Ω·cm2 even after the immersion time of 50 days in 3.5 wt.% NaCl solution, showing an extraordinary performance of corrosion resistance. The enhanced anticorrosion performance of composite coating could be resulted from the apparently increased dispersibility and compatibility of MoS2 in WEP.

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.

scholarly journals Influence of PAA on the Microstructure and Corrosion Resistance of Electrophoretically Deposited SiO2 and Ni/SiO2 Coatings on X2CrNiMo17-12-2 Steel

2017 ◽  
Vol 62 (4) ◽  
pp. 2073-2079
Author(s):  
T. Ratajski ◽  
I. Kalemba-Rec ◽  
B. Dubiel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Chemical Composition ◽  
Anionic Surfactant ◽  
Polyacrylic Acid ◽  
Deposition Time ◽  
Nacl Solution ◽  
Transmission Electron

AbstractThe effect of anionic surfactant in the form of polyacrylic acid (PAA) on the electrophoretic deposition of the SiO2and Ni/SiO2coatings on X2CrNiMo17-12-2 stainless steel was examined. Parameters of the process, such as chemical composition of the suspensions, voltage between the electrodes and the deposition time were experimentally selected. Zeta potential measurements showed a beneficial effect of polyacrylic acid on the SiO2and Ni particles stability in ethanol. Scanning and transmission electron microscopy studies revealed that the microstructure of the coatings obtained from the suspensions containing polyelectrolyte is more homogenous and has less amount of desiccation cracks on the surface. The results of the polarization tests have shown that addition of anionic surfactant improves also corrosion resistance of the coatings in 3.5% NaCl solution.

The Influence of Deformation the Corrosion Resistance of Titanium Grade2

2015 ◽  
Vol 227 ◽  
pp. 27-30 ◽  
Author(s):  
Marta Zwolińska ◽  
Agata Sotniczuk ◽  
Krzysztof Topolski ◽  
Andrzej Królikowski ◽  
Halina Garbacz
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Room Temperature ◽  
Electrochemical Impedance ◽  
Extrusion Direction ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Transmission Electron

Severe Plastic Deformation (SDP) processes including Hydroextrusion (HE) causes the change of the mechanical properties by the introduction of a large number of defects and significant refinement of the microstructure. During the initially stages of HE microstructure becomes more elongated according to the extrusion direction. Only after a certain deformation, grains become more equiaxed. Present studies are intended to determine the influence of the titanium Grade2 microstructure and grain size distribution on its corrosion properties. All corrosion tests were conducted in a 0.9 % NaCl solution at room temperature. Electrochemical Impedance Spectroscopy (EIS) was measured after 2 and 24 hours. Also Potentiodynamic Polarization was conducted after 24 hours. Microstructures were reviled using Scanning Electron Microscopy and Transmission Electron Microscopy. Grain size distribution was determined using the program Micrometer . The results confirmed formation of titanium dioxide and very good corrosion properties of titanium Grade2 at all stages of hydrostatic extrusion.

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