scholarly journals Adsorption of Polyions on Flat TiO2 Surface

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1164
Author(s):  
Tin Klačić ◽  
Jozefina Katić ◽  
Danijel Namjesnik ◽  
Jasmina Jukić ◽  
Davor Kovačević ◽  
...  
Keyword(s):  
Corrosion Protection ◽  
Surface Potential ◽  
Electrochemical Impedance ◽  
Substrate Surface ◽  
Titanium Substrate ◽  
Tio2 Surface ◽  
Corrosion Properties ◽  
Inner Surface ◽  
Before And After ◽  
Titanium Material

In this study, the surface properties of Ti/TiO2 substrate before and after the adsorption of polyelectrolytes were investigated. As model polyelectrolytes, strongly charged polycation poly(diallyldimethylammonium) (PDADMA) and strongly charged polyanion poly(4-styrenesulfonate) (PSS) were used. Initially, the bare titanium substrate was characterized by means of ellipsometry, atomic force microscopy (AFM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and measurements of inner surface potential using crystal electrode (CrE). It was shown that the substrate surface is very smooth with the roughness of 3.5 nm and oxide layer thickness of 3.8 nm. After the adsorption of PDADMA and PSS, polyelectrolyte-coated titanium surface was examined using the above-mentioned methods under the same conditions. It was found that both PDADMA cations and PSS anions form a stable polymeric nanofilm on Ti/TiO2 surface that partially covers the surface, without significant impact on the surface roughness. The corrosion protection effectiveness values indicate that the corrosion properties were greatly enhanced upon polyion adsorption and polyelectrolyte coating formation on the flat TiO2 surface. The obtained results were additionally confirmed by inner surface potential measurements. According to the methods employed, PDADMA nanofilm modification offers enhanced corrosion protection to the underlying titanium material in sodium chloride electrolyte solution.

scholarly journals Acrylate-Based Hybrid Sol-Gel Coating for Corrosion Protection of AA7075-T6 in Aircraft Applications: The Effect of Copolymerization Time

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 948 ◽  
Author(s):  
Peter Rodič ◽  
Romana Cerc Korošec ◽  
Barbara Kapun ◽  
Alenka Mertelj ◽  
Ingrid Milošev
Keyword(s):  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Condensation Reaction ◽  
Energy Dispersive Spectrometer ◽  
Sol Gel ◽  
Gel Permeation Chromatography ◽  
Corrosion Attack ◽  
Scanning Calorimetry ◽  
Corrosion Properties ◽  
Pressure Differential Scanning Calorimetry

Pre-hydrolysed/condensed tetraethyl orthosilicate (TEOS) was added to a solution of methyl methacrylate (MMA) and 3-methacryloxypropyltrimethoxysilane (MAPTMS), and then copolymerised for various times to study the influence of the latter on the structure of hybrid sol-gel coatings as corrosion protection of aluminium alloy 7075-T6. The reactions taking place during preparation were characterised using real-time Fourier transform infrared spectroscopy, dynamic light scattering and gel permeation chromatography. The solution characteristics were evaluated, using viscosimetry, followed by measurements of thermal stability determined by thermogravimetric analysis. The optimal temperature for the condensation reaction was determined with the help of high-pressure differential scanning calorimetry. Once deposited on 7075-T6 substrates, the coatings were evaluated using a field emission scanning electron microscope coupled to an energy dispersive spectrometer to determine surface morphology, topography, composition and coating thickness. Corrosion properties were tested in dilute Harrison’s solution (3.5 g/L (NH4)2SO4 and 0.5 g/L NaCl) using electrochemical impedance spectroscopy. The copolymerization of MMA and MAPTMS over 4 h was optimal for obtaining 1.4 µm thick coating with superior barrier protection against corrosion attack (|Z10 mHz| ~ 1 GΩ cm2) during three months of exposure to the corrosive medium.

Study of Microstructure and Corrosion Resistance of Zinc Electrodeposits before and after Black Chromating

2017 ◽  
Vol 751 ◽  
pp. 119-124
Author(s):  
Kanokwan Saengkiettiyut ◽  
Pranee Rattanawaleedirojn ◽  
Adisak Thueploy ◽  
Jumpot Wanichsampan ◽  
Yuttanant Boonyongmaneerat
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Alkaline Electrolyte ◽  
Corrosion Properties ◽  
Electrochemical Testing ◽  
Before And After ◽  
Coat Layer ◽  
Zinc Coatings ◽  
Salt Spray Testing

In this work, microstructure and corrosion properties of zinc electroplated steel before and after black chromating was investigated. The test samples were prepared by electrodeposition process, using a commercially-available alkaline electrolyte. Subsequently, the galvanized samples were applied with a black chromate-based passivation layer and a clear top-coat layer. Their microstructures were examined using X-ray diffractometry and scanning electron microscopy. The corrosion resistance of the samples was assessed with the salt spray test, following the ASTM B117, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization in 5 wt.% NaCl solutions. The study showed that zinc electroplated steels exhibit (110) crystallographic orientation. The passivation and top-coat layers did not affect the microstructure of the zinc layer, and covered uniformly on the zinc layer for all sets of samples. The corrosion resistant results obtained from salt spray testing and electrochemical testing revealed that the microstructure of zinc coatings prepared by using different applied current did not influence on their corrosion resistance markedly. While black passivation followed by top coating provided a significant improvement on corrosion resistance of the coatings.

scholarly journals Electrochemical corrosion characteristics of phosphated S355J2 steel in sulfate environment

2016 ◽  
Vol 60 (4) ◽  
pp. 107-113 ◽  
Author(s):  
F. Pastorek ◽  
K. Borko ◽  
S. Dundeková ◽  
S. Fintová ◽  
B. Hadzima
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Surface Preparation ◽  
Corrosion Properties ◽  
Preparation Methods ◽  
Surface Pretreatment ◽  
Chemical Surface ◽  
Phosphate Layer ◽  
Before And After ◽  
The Right

Abstract Large number of mechanical and chemical surface pretreatment techniques is actually used on steels in industrial practice. Choosing the right combination of these technologies is one of the most important tasks for many applications. The purpose of this research was to evaluate the influence of selected mechanical surface preparation methods (grinding, sandblasting) on the quality and electrochemical corrosion characteristics of S355J2 steel before and after the final chemical surface treatment by the technology of manganese phosphating. The surface morphology of the formed phosphate layer was evaluated by a scanning electron microscopy (SEM) and the cross section analysis was performed by a light metallographic microscopy. 0.1M Na2SO4 solution simulating aggressive industrial pollution was selected for electrochemical corrosion tests. Impact evaluation of various mechanical and chemical surface treatments on the corrosion properties of the tested steel was realized by potentiodynamic polarization tests (PD) and electrochemical impedance spectroscopy (EIS) using the Tafel analysis and equivalent circuits method respectively. The obtained results proved that sandblasting negatively affected the corrosion resistance of S355J2 steel and subsequently created manganese phosphate layer.

scholarly journals Influence of Heat Treatment on Corrosion Properties of Non-Alloy Steel in Acidic Environment

2019 ◽  
Vol 26 (3) ◽  
pp. 181-188
Author(s):  
Sylwia Polasz
Keyword(s):  
Heat Treatment ◽  
Corrosion Protection ◽  
Alloy Steel ◽  
Electrochemical Impedance ◽  
Corrosion Properties ◽  
Laboratory Methods ◽  
Machine Elements ◽  
Zinc Coatings ◽  
Cathode Protection ◽  
Potentiodynamic Method

Abstract The article presents the influence of heat treatment on corrosion properties of non-alloy steel. This steel is used in machine elements. Heat treatment has a major impact on corrosion resistance of steel materials. Laboratory methods for measuring the corrosion rate consist of Electrochemical Impedance Spectroscopy and polarization curves. Instead of these types, there are also industrial methods of velocity corrosion measurements like researches in natural conditions and coupons corrosimetry. These days the most popular techniques of corrosion measurements are electrochemical measurements. In order to conduct impact assessments influent of heat treatment to corrosion properties there is need to proceed few steps like prepare samples, carry out heat treatment, hardness measurements, metallographical examination, prepare samples for corrosion and proceed corrosion researches by potentiodynamic method. An important element during researches is corrosion allowance, which has an impact influent on corrosion properties. This is the most popular and efficient method of corrosion protection. These days for corrosion protection are use paints or zinc coatings, cathode protection or stainless.

scholarly journals The Influence of Adding a Functionalized Fluoroalkyl Silanes (PFDTES) into a Novel Silica-Based Hybrid Coating on Corrosion Protection Performance on an Aluminium 2024-t3 Alloy

2021 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Magdi H. Mussa ◽  
Yaqub Rahaq ◽  
Sarra Takita ◽  
Farah D. Zahoor ◽  
Nicholas Farmilo ◽  
...  
Keyword(s):  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Chemical Elements ◽  
Sol Gel ◽  
Hybrid Coating ◽  
Circuit Element ◽  
Before And After ◽  
Impedance Testing ◽  
Pre Treatment ◽  
Marine Applications

Silica-based coatings prepared using sol-gel polymerizing technology have been shown to exhibit excellent chemical stability combined with reducing the corrosion of metal substrates, showing promising use in aerospace and marine applications to protect light alloys. Moreover, this technology is an eco-friendly technique route for producing surface coatings, showing high potential for replacing toxic pre-treatment coatings of traditional conversation chromate coatings. This study aims to investigate the enhancement in corrosion protection of a hybrid-organic-inorganic silica-based coating cured at 80 °C by increasing the hydrophobicity to work on the aluminium 2024-T3 alloy. This approach involving a novel silica-based hybrid coating was prepared by introducing 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) into the base hybrid formula created from tetraethylorthosilicatesilane (TEOS) and triethoxymethylsilane (MTMS) precursors; this formula was enhanced by introducing a Polydimethylsiloxane polymer (PDMS). The corrosion protection properties of these coatings were examined by being immersed in 3.5% NaCl with electrochemical impedance testing (EIS) and Potentiodynamic polarization scanning (PDPS). The chemical elements confirmation was performed using infrared spectroscopy (ATR-FTIR); all this was supported by analysing the surface morphology before and after the immersion by using scanning electron microscopy (SEM). The results of the electrochemical impedance testing analyses reveal the new open finite-length diffusion circuit element due to electrolyte media diffusion prevented by fluorinated groups. Additionally, it shows increases in corrosion protection arising from the increasing hydrophobicity of the fluorinated coating compared to other formulas cured under similar conditions and bare substrate. Additionally, the modified sol-gel exhibited improved resistance to cracking, while the increased hydrophobicity may also promote self-cleaning.

scholarly journals Influence of Abrasive Load on Wettability and Corrosion Inhibition of a Commercial Superhydrophobic Coating

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 887
Author(s):  
Arjun Manoj ◽  
Rahul Ramachandran ◽  
Pradeep L. Menezes
Keyword(s):  
Contact Angle ◽  
Corrosion Inhibition ◽  
Mechanical Stability ◽  
Electrochemical Impedance ◽  
Contact Angle Hysteresis ◽  
Open Circuit ◽  
Superhydrophobic Coating ◽  
Corrosion Properties ◽  
Wetting Properties ◽  
Before And After

The poor mechanical stability of hydrophobic and superhydrophobic surfaces and coatings severely hinder their commercial and industrial applicability. In addition to being expensive and time-consuming to manufacture, the ability of these coatings to maintain their non-wetting properties after mechanical abrasion and wear is currently not well-understood. In this work, the influence of increasing abrasive loads on the roughness, wettability, and corrosion inhibition properties of a commercial superhydrophobic coating was studied. It was shown that the wetting and corrosion properties of the superhydrophobic coating was affected by the abrasive load. Increasing abrasive loads were applied using a tribometer and the electrochemical response was studied using open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. The wetting and roughness behavior of the coating before and after the application of the abrasive load was characterized using contact angle, contact angle hysteresis, and optical profilometry. The protective properties of the superhydrophobic coating was observed to deteriorate as the abrasive load increased. Similarly, after a specific abrasive load, the coating transitioned from the Cassie-Baxter state of wetting into that of the Wenzel state.

scholarly journals The Effect of the Methyl and Ethyl Group of the Acrylate Precursor in Hybrid Silane Coatings Used for Corrosion Protection of Aluminium Alloy 7075-T6

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 172 ◽  
Author(s):  
Damir Hamulić ◽  
Peter Rodič ◽  
Matic Poberžnik ◽  
Marjan Jereb ◽  
Janez Kovač ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
Corrosion Protection ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Chemical Properties ◽  
Molar Ratio ◽  
Infrared Spectrometry ◽  
Corrosion Properties ◽  
Ethyl Methacrylate

This study investigated polysiloxane hybrid sol-gel coatings synthesized from tetraethyl orthosilicate (TEOS), 3-(trimethoxysilyl)propyl methacrylate (MAPTMS) and two different precursors, i.e., methyl- or ethyl- methacrylate (MMA or EMA), as corrosion protection of aluminium alloy 7075-T6. The hypothesis was that the additional alkyl group might affect the chemical properties and, consequently, the corrosion properties. Synthesis of the sols proceeded in two steps, each involving either MMA or EMA in the same molar ratio. The resulting sols, siloxane-(poly(methyl methacrylate-co-MAPTMS)) or siloxane-(poly(ethyl methacrylate-co-MAPTMS)), were applied on aluminium alloy followed by characterization in terms of chemical structure and composition, topography, wettability, adhesion and corrosion resistance in 0.1 M sodium chloride solution. The chemical properties of sols, monoliths and coatings were investigated using Fourier transform infrared spectrometry, solid state nuclear magnetic resonance spectrometry, X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. Coatings were similar in terms of surface topography, while the wettability of the coating with EMA showed 6° greater water contact angle compared to the coating with MMA. Both coatings were shown, by electrochemical impedance spectroscopy in 0.1 M NaCl solution, to act as barriers to protect the underlying substrate in which coating with EMA exhibits better protection properties after 2 months of immersion. Adhesion tests confirmed the highest grade of adhesion to the substrate for both coatings. Testing in a salt-spray chamber demonstrated excellent corrosion protection, where coatings remaining intact after more than 600 h of exposure.

Protection of Aluminium Alloys via Hybrid Sol-Gel Coatings with Encapsulated Organic Corrosion Inhibitors

2006 ◽  
Vol 519-521 ◽  
pp. 661-666 ◽  
Author(s):  
A.N. Khramov ◽  
V.N. Balbyshev ◽  
R.A. Mantz
Keyword(s):  
Corrosion Protection ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Substrate Surface ◽  
Sol Gel ◽  
Matrix Material ◽  
The Matrix ◽  
Aluminum Alloy 2024 ◽  
Structural Hybrid ◽  
Organic Corrosion Inhibitors

Several heterocyclic organic corrosion inhibitors that contain ionazible functional group were encapsulated into nano-structural hybrid organo-silicate coating to improve its corrosion protection performance on aluminum alloy 2024-T3 substrate. When the coating is formed on the substrate surface, it serves simultaneously as protective barrier and as a reservoir for leachable corrosion inhibitor that is stored and released through the mechanism of reversible ionic interaction with the matrix material. The efficiency of active corrosion protection for these coating systems was examined by electrochemical methods including potentiodynamic polarization (PDS) and electrochemical impedance spectroscopy (EIS). The effects of chemical structure and the loading concentration of the inhibitor within the coating were determined.

Novel Electroless Deposited Corrosion – Resistant and Anti-Bacterial NiP–TiNi Nanocomposite Coatings

2020 ◽  
Author(s):  
Eman Fayyad ◽  
Aboubakr Abdullah ◽  
Mohamed Hassan ◽  
Abdul Rasheed Pathath ◽  
Khaled Mahmoud ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Composite Coating ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Antibacterial Properties ◽  
Amorphous Structure ◽  
Nanocomposite Coatings ◽  
Colony Counting ◽  
Before And After

From acidic NiP electroless bath, the co-deposition of TiNi nanoparticles in the NiP matrix to form novel NiP-TiNi nanocomposite coatings (NCCs) on top of API X100 carbon steel using several concentrations of TiNi nanoparticles (0.2, 0.4 and 0.8 g L-1 in the bath) is successfully achieved. The influence of the TiNi nanoparticles on the composition, deposition rate, thickness, and morphology of the NiP coating are investigated before and after annealing at 400 oC. The addition of TiNi nanoparticles into the NiP matrix led to the transform of the amorphous structure of the as-plated NiP into a semi-crystalline one. The microhardness of the composite coating significantly enhances with increasing TiNi concentration up to 0.4 g L-1 and further improvement takes place after heat treatment. The electrochemical impedance spectroscopy (EIS) and the colony counting method are carried out to assess the corrosion protection and antibacterial properties, respectively, of the as-deposited and the annealed coatings. The results demonstrate that there is an optimum concentration for the addition of TiNi (0.4 g L-1), which offers the composite coating with the highest corrosion protection that reaches to about 98 %. Below and beyond this concentration as well as after heat treatment, the improvement in the corrosion protection of the composite coatings slightly decreases. Besides, the NiP–TiNi NCCs have effective antibacterial properties as it decreased the cell viability of Escherichia coli from 100 to 19%.

Influence of irradiation intensity on corrosion properties of microarc oxidation film on AZ31 magnesium alloy with HIPIB

2019 ◽  
Vol 66 (4) ◽  
pp. 418-424
Author(s):  
X.G. Han ◽  
J.F. Lv ◽  
Y.Z. Chen ◽  
Y.C. Shan ◽  
J.J. Xu
Keyword(s):  
Magnesium Alloy ◽  
Electrochemical Impedance ◽  
Ion Beam ◽  
Substrate Surface ◽  
Microarc Oxidation ◽  
Film Surface ◽  
Az31 Magnesium Alloy ◽  
Electrochemical Impedance Spectrum ◽  
Corrosion Properties ◽  
Content Type

Purpose The purpose of this paper is to investigate the effect of high-intensity pulsed ion beam (HIPIB) intensity on the structure and corrosive properties of microarc oxidation (MAO) films on AZ31 magnesium alloy and explore the mechanism for modified anti-corrosion properties of irradiated films. Design/methodology/approach The energy deposited on the coating surface influences the remelting process of the MAO coatings significantly, which was closely related to the intensity of HIPIB; therefore, HIPIB with various intensities of 100-350 A/cm2, was selected to modify the MAO films on AZ31 magnesium alloy. The changes in film structure and phase structure of modified films were characterized by scanning electron microscopy and X-ray diffractometry (XRD) with CuKα, respectively. The corrosive behavior of the MAO films was featured with polarization curves and electrochemical impedance spectrum in 3.5 per cent NaCl solution on a PAR 2273 electrochemical workstation. Findings The results clearly show that a dense, continual and remelted layer with a few micrometers in thickness was obtained on the irradiated surface at 200 A/cm2, which are mainly responsible for the modified and optimal anti-corrosion property of MAO films by suppressing/retarding the process of the corrosive electrolyte infiltration into magnesium substrate surface. Originality/value The paper reveals that HIPIB irradiation could modify the corrosion resistance by producing a remelted compact layer on the MAO film surface at a suitable irradiation parameter and explored the modified mechanism of MAO films.

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