scholarly journals 3-Mercaptopropanoic Acid-Doped Chitosan/Hybrid-Based Multilayer Sol-Gel Coatings for Cu Protection in 3.5% NaCl Solution

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3743
Author(s):  
Jaganathan Balaji ◽  
Tae Hwan Oh
Keyword(s):  
Corrosion Protection ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Modified Electrodes ◽  
Dense Layer ◽  
Nacl Solution ◽  
X Ray ◽  
Assembly Technique

In this work, biopolymer based sol-gel was synthesized by doping 3-mercaptopropanoic acid (MPA) with chitosan and a hybrid of 3-glycidoxypropyltrimethoxysilane (GPTMS) and tetraethoxysilane (TEOS). Prepared MPA/hybrid-doped chitosan was applied toa copper (Cu) metal surface by the self-assembly technique to protect the Cu metal from corrosion in a 3.5% NaCl solution. The structure, mechanism and morphology of the modified electrodes were examined using Fourier transform infra-red (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy (AFM). The decrease in surface roughness for Hy/chitosan/MPA-coated Cu indicates the formation of a dense layer on Cu metal confirmed by AFM. The corrosion protection evaluation of sol-gel coated electrodes was analyzed using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies (PDS) in a 3.5% NaCl medium. The MPA/hybrid-doped chitosan sol-gel coated Cu metal showed the greatest resistance to corrosionthanother sol-gel modified electrodes. The MPA-doped-chitosan/Hy sol-gel coating protected the Cu metal by an anodic dissolution process and improved its corrosion protection to 99.9%.

scholarly journals Degradation of Sol-Gel Acrylic Coatings Based on Si and Zr Investigated Using Electrochemical Impedance, Infrared and X-Ray Photoelectron Spectroscopies

2021 ◽  
Vol 8 ◽  
Author(s):  
Peter Rodič ◽  
Sandrine Zanna ◽  
Ingrid Milošev ◽  
Philippe Marcus
Keyword(s):  
Corrosion Protection ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Ion Beam ◽  
Salt Spray ◽  
Sol Gel ◽  
Synthesis Process ◽  
Corrosion Properties ◽  
X Ray ◽  
Acrylic Coatings

This study aimed to synthesise and characterise two types of sol-gel acrylic coatings: one based on Si and the other based on Si and Zr. These coatings, which served as a barrier for corrosion protection of aluminium, were synthesised by sol-gel methodology using silicon precursors tetraethyl orthosilicate and organically modified silicon precursor 3-methacryloxypropyltrimethoxysilane, without and with the addition of zirconium(IV) n-propoxide chelated with methacrylic acid. The synthesis process was followed using real-time Fourier transform infrared spectroscopy, which confirmed the condensation reactions of Si–O–Si and Si–O–Zr networks, depending on the sol type. This was reflected in the composition of the coating as well, as shown by X-ray photoelectron spectroscopy. The coating topography, thickness and morphology were analysed using focused ion beam scanning electron microscopy. X-ray photoelectron spectroscopy was employed to follow the degradation of acrylic coatings upon immersion in sodium chloride solution. Corrosion properties, evaluated using electrochemical impedance spectroscopy in 0.1 M NaCl, confirmed high barrier protection of coated aluminium with acrylic coatings based on Si and even better for coating based on Si with Zr. The more durable corrosion protection of the latter was also confirmed by salt spray testing.

scholarly journals Enhanced Corrosion Protection of Epoxy/ZnO-NiO Nanocomposite Coatings on Steel

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 783 ◽  
Author(s):  
Muna Ibrahim ◽  
Karthik Kannan ◽  
Hemalatha Parangusan ◽  
Shady Eldeib ◽  
Omar Shehata ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Morphological Characterization ◽  
Coated Steel ◽  
X Ray ◽  
Edax Analysis

ZnO-NiO nanocomposite with epoxy coating on mild steel has been fabricated by the sol–gel assisted method. The synthesized sample was used to study corrosion protection. The analysis was performed by electrochemical impedance spectroscopy in 3.5% NaCl solution. The structural and morphological characterization of the metal oxide nanocomposite was carried out using XRD and SEM with Energy Dispersive Absorption X-ray (EDAX) analysis. XRD reveals the ZnO-NiO (hexagonal and cubic) structure with an average ZnO-NiO crystallite size of 26 nm. SEM/EDAX analysis of the ZnO-NiO nanocomposite confirms that the chemical composition of the samples consists of: Zn (8.96 ± 0.11 wt.%), Ni (10.53 ± 0.19 wt.%) and O (80.51 ± 3.12 wt.%). Electrochemical Impedance Spectroscopy (EIS) authenticated that the corrosion resistance has improved for the nanocomposites of ZnO-NiO coated along with epoxy on steel in comparison to that of the pure epoxy-coated steel.

Preparation of Poly(diallydimethyl ammonium chloride) (PDDA)/Au Nanocomposite Film by In Situ Electrochemical Reduction and its Electrocatalytic Properties

2010 ◽  
Vol 123-125 ◽  
pp. 189-192
Author(s):  
Hong Wei Shi ◽  
Li Zhang ◽  
Cong Wang ◽  
Ke Ying Zhang
Keyword(s):  
Electrochemical Reduction ◽  
Ammonium Chloride ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Layer By Layer ◽  
X Ray ◽  
Assembly Technique

Nanocomposite films containing Au nanoparticles were fabricated by alternating adsorption of poly(diallydimethyl ammonium chloride) (PDDA) and HAuCl4 using layer-by-layer self-assembly technique and subsequent in situ electrochemical reduction of the AuCl4- ions. The composition and properties of the composite films were characterized by ultraviolet-visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV).The UV-vis characteristic absorbances of PDDA and Au increase almost linearly with the number of bilayers, which suggests a progressive deposition with almost an equal amount of the PDDA and Au in each cycle. X-ray photoelectron spectroscopy further confirms the presence of the main components (such as PDDA and Au) of the nanocomposite films. Furthermore, the nanocomposite films also exhibit good electrocatalytic activity for the oxidation of ascorbic acid (AA), which may be used in electrochemical biosensors.

Introduction of Li+ Ions into Anodic Film by Hydrotalcite Precursor and Electrochemical Behavior

2006 ◽  
Vol 11-12 ◽  
pp. 509-512 ◽  
Author(s):  
Hao Ye ◽  
Yu Zuo ◽  
Jin Ping Xiong ◽  
Jing Mao Zhao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Anodic Film ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
Precursor Method ◽  
X Ray ◽  
Al Composite ◽  
High Purity Aluminum

Lithium ion was introduced into high purity aluminum (99.999%) by hydrotalcite precursor method, and Li/Al composite anodic film was obtained by anodizing. The methods of X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the properties of the anodic film. The electrochemistry behaviors of composite anodic film were studied by means of potentiodynamic method and electrochemical impedance spectroscopy (EIS). The results showed that the composite anodic film was produced by hydrotalcite precursor method and which is amorphous to X-ray diffraction. The passivation current density of the anodic film in NaCl solution (1mol/L, pH=3, 7, 11) decreased obviously, while impedance value increased sharply. Corrosion resistance of the composite anodic film in NaCl solution was improved by the introduction of Li+ ion.

scholarly journals Effect of immersion time at the stainless steel 304L/NaCl (0.01 M) interface

2019 ◽  
Vol 9 (2) ◽  
pp. 99-111
Author(s):  
Wejdene Mastouri ◽  
Luc Pichon ◽  
Serguei Martemianov ◽  
Thierry Paillat ◽  
Anthony Thomas
Keyword(s):  
Stainless Steel ◽  
Photoelectron Spectroscopy ◽  
Immersion Time ◽  
Surface Composition ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Nacl Solution ◽  
Aisi 304L ◽  
X Ray ◽  
Steel Aisi

Stainless steels are broadly used thanks to their specific physical properties such as their high corrosion resistance in poorly aggressive solutions. However, only few studies have been reported in the literature concerning their electrochemical behavior in low concentration electrolytes medium. Accordingly, the present work aims to study the immersion time influence on the solid-liquid interface properties of the austenitic stainless steel AISI 304L, immersed in a low-concentrated (0.01 M) sodium chloride (NaCl) solution. The electroche­mical behavior of the interface was evaluated by electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) monitoring. The morphological features and the modification of the surface composition were evaluated by Optic Microscopy, Scanning Electron Microscopy, Energy Dispersive X-ray Spectrometry, Atomic Force Microscopy, White Light Interferometry and X-ray Photoelectron Spectroscopy. It was determined by OCP measurement that the characteristic time of the interface stabilization is very long (several months). After an immersion of 2 months in NaCl solution, a second time constant on impedance phase diagram appears. Surface characterizations reveal a significant modifi­cation of the morphology and chemistry of the AISI 304L surface that can be linked to OCP/EIS observations. It can be noticed that the repeatability deviation of the EIS method was about 1 % while its reproducibility deviation was estimated to 35 %.

scholarly journals New Strategy of Using Stannic Oxide as Catalyst in a Three-dimension Electrode Reactor for the Electro-oxidation of Organic Matter

2014 ◽  
Vol 17 (4) ◽  
pp. 243-249
Author(s):  
Peng Li ◽  
Yuemin Zhao ◽  
Lizhang Wang ◽  
Binbin Ding ◽  
Yunlong Hu
Keyword(s):  
Organic Matter ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Oxygen Demand ◽  
Simultaneous Increase ◽  
Stannic Oxide ◽  
Three Dimension ◽  
X Ray ◽  
Electro Oxidation

An efficient organic-matter (OM) degradation strategy using synthetic electrocatalysis particles as fixed filler in a threedimension electrode reactor was developed. In our work, SnO2-granular active carbon (SnO2-GAC) was prepared by integrating GAC with nano-SnO2 via the sol-gel method, using SnCl4 as starting material and gelatin as a stabilizer. The phase composition and micromorphology of the particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning/transmission electron microscopy techniques. The results showed the incorporation of SnO2 crystallized in a tetragonal lattice with an average crystallite size of 10.6 nm, which was easily accessible on the GAC surface and mesopores. Electrochemical properties were tested with cyclic voltammetry and electrochemical impedance spectroscopy methods that disclosed an improved response current with a simultaneous increase in anodic area, while the charge-transfer and electrolyte resistance obviously decreased, in contrast to the virgin GAC filler in the three-dimension electrode system. Although the energy consumption of SnO2-GAC (11.71 kWh·kg−1 COD) presented slight superiority than that of GAC (13.62 kWh·kg−1 COD) at the same chemical oxygen demand (COD) conversion of 98 % when a current density of 20 A·m−2 was employed for phenolic wastewater treatment, the required degradation time of the former (47.22 h) is greatly decreased compared with that of the latter (54.24 h). These results obviously confirm the superiority of the prepared SnO2-GAC in electro-oxidation of organic matters.

scholarly journals Study of the Corrosion Process of AZ91D Magnesium Alloy during the First Hours of Immersion in 3.5 wt.% NaCl Solution

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Vanessa Mandarano Pinela ◽  
Leandro Antônio de Oliveira ◽  
Mara Cristina Lopes de Oliveira ◽  
Renato Altobelli Antunes
Keyword(s):  
Magnesium Alloy ◽  
Photoelectron Spectroscopy ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Corrosion Process ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Nacl Solution ◽  
X Ray ◽  
Az91d Magnesium Alloy

The AZ91D magnesium alloy was immersed in 3.5 wt.% NaCl solution at room temperature for times ranging from 1 minute up to 72 hours. The aim was to investigate the evolution of the corrosion process using confocal laser scanning microscopy (CLSM), electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy. The microstructure of the as-received alloy was initially characterized by optical microscopy and scanning electron microscopy (SEM). The crystalline phases were identified by X-ray diffractometry. The main phases were primary-α, eutectic-α, and β (Mg17Al12). Vickers microhardness markings were made on the surface of one etched sample to facilitate the identification of the same region at each different immersion time, thus enabling the observation of the corrosion process evolution. Corrosion initiates at the grain boundaries of the eutectic microconstituent and, then, propagates through primary α-grains. The β-phase was less severely attacked.

scholarly journals Facile fabrication of mesostructured natural rubber/silica nanocomposites with enhanced thermal stability and hydrophobicity

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Supphathee Chaowamalee ◽  
Chawalit Ngamcharussrivichai
Keyword(s):  
Natural Rubber ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Sol Gel ◽  
X Ray ◽  
Silica Nanocomposites ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Silica Wall ◽  
Adsorption Desorption

AbstractNatural rubber (NR)/hexagonal mesoporous silica (HMS) nanocomposites (NRHMS) with enhanced thermal and hydrophobic properties were facilely prepared via in situ sol–gel formation with pH adjustment using a low sulphuric acid (H2SO4) acid concentration. The effect of the amount of 0.5 M H2SO4 (2.5–10 g) added into the pre-synthesis mixture on the physicochemical properties of the obtained NRHMS nanocomposites was investigated. With a small addition of H2SO4 solution, the fabricated NRHMS nanocomposite possessed an improved wormhole-like mesostructure arrangement with a thicker silica wall, which retarded the thermal decomposition of the NR phase, as deduced from the auto-oxidation of NR by thermogravimetric analysis. The H2O adsorption–desorption measurement revealed an increased hydrophobicity of the NRHMS composites, explained by the acid-catalyzed bridging of free silanol groups to siloxane bonds, which was supported by the X-ray photoelectron spectroscopy analysis. Scanning transmission electron microscopy with energy dispersive X-ray spectroscopy elemental mapping revealed a good dispersion of the NR phase within the mesostructured silica. However, a high amount of added H2SO4 solution led to silica–NR phase separation due to the decreased hydrophobic interaction between the silica precursor and rubber chain, as well as an agglomeration of the NR phase itself. The mechanism of NRHMS nanocomposite formation under pH-controlled conditions was proposed to proceed via a cooperative self-assembly route.

scholarly journals Effect of Hf-doping on electrochemical performance of anatase TiO 2 as an anode material for lithium storage

2018 ◽  
Vol 5 (6) ◽  
pp. 171811 ◽  
Author(s):  
Sergey V. Gnedenkov ◽  
Sergey L. Sinebryukhov ◽  
Veniamin V. Zheleznov ◽  
Denis P. Opra ◽  
Elena I. Voit ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Sol Gel ◽  
Outer Diameter ◽  
Lithium Storage ◽  
X Ray

Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol–gel method on carbon fibre. Physico-chemical properties of the as-synthesized materials were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, scanning transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry analysis and Brunauer–Emmett–Teller measurements. It was confirmed that Hf 4+ substitute in the Ti 4+ sites, forming Ti 1– x Hf x O 2 ( x  = 0.01; 0.03; 0.05) solid solutions with an anatase crystal structure. The Ti 1– x Hf x O 2 materials are hollow microtubes (length of 10–100 µm, outer diameter of 1–5 µm) composed of nanoparticles (average size of 15–20 nm) with a surface area of 80–90 m 2  g –1 and pore volume of 0.294–0.372 cm 3  g –1 . The effect of Hf ion incorporation on the electrochemical behaviour of anatase TiO 2 in the Li-ion battery anode was investigated by galvanostatic charge/discharge and electrochemical impedance spectroscopy. It was established that Ti 0.95 Hf 0.05 O 2 shows significantly higher reversibility (154.2 mAh g –1 ) after 35-fold cycling at a C /10 rate in comparison with undoped titania (55.9 mAh g –1 ). The better performance offered by Hf 4+ substitution of the Ti 4+ into anatase TiO 2 mainly results from a more open crystal structure, which has been achieved via the difference in ionic radius values of Ti 4+ (0.604 Å) and Hf 4+ (0.71 Å). The obtained results are in good accord with those for anatase TiO 2 doped with Zr 4+ (0.72 Å), published earlier. Furthermore, improved electrical conductivity of Hf-doped anatase TiO 2 materials owing to charge redistribution in the lattice and enhanced interfacial lithium storage owing to increased surface area directly depending on the Hf/Ti atomic ratio have a beneficial effect on electrochemical properties.

Investigation of two-component mixed self-assembled monolayers on gold

2001 ◽  
Vol 79 (3) ◽  
pp. 328-336
Author(s):  
Zhen Wang ◽  
Yan-Li Shi ◽  
Hu-Lin Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Electrochemical Impedance ◽  
Impedance Analysis ◽  
Self Assembled Monolayers ◽  
X Ray ◽  
Molar Ratios ◽  
Two Component ◽  
Assembled Monolayers ◽  
Self Assembled

Two-component mixed self-assembled monolayers (SAMs) composed of 2-mercapto-5-methyl-1,3,4-oxadiazole (MMO) and 1-dodecanethiol (C12SH) in various molar percentages were prepared on gold surfaces by self-assembly. X-ray photoelectron spectroscopy (XPS) and wettability results gave evidence that the coverage of MMO was controlled by the composition of MMO in the assembling solution. The monolayer coverage and apparent rate constant of the redox active probes in solution of different molar ratios of mixed SAMs could be calculated using impedance measurements. The cyclic voltammetry reveals that the probes are selectively passed through the mixed SAMs depending upon their properties.Key words: self-assembled monolayers (SAMs), X-ray photoelectron spectroscopy (XPS), electrochemistry, electrochemical impedance analysis.

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