scholarly journals Hybrid Zinc-Based Multilayer Systems with Improved Protective Ability against Localized Corrosion Incorporating Polymer-Modified ZnO or CuO Particles

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1223
Author(s):  
Nelly Boshkova ◽  
Kamelia Kamburova ◽  
Tsetska Radeva ◽  
Nikolai Boshkov
Keyword(s):  
Protective Coatings ◽  
Steel Substrate ◽  
Zinc Coating ◽  
Optical Microscope ◽  
Cuo Nanoparticles ◽  
Localized Corrosion ◽  
Hybrid Coatings ◽  
Low Carbon ◽  
Cathodic Current ◽  
Protective Ability

Localized corrosion and biofouling cause very serious problems in the marine industries, often related to financial losses and environmental accidents. Aiming to minimize the abovementioned, two types of hybrid Zn-based protective coatings have been composed. They consist of a very thin underlayer of polymer-modified ZnO or CuO nanoparticles and toplayer of galvanic zinc with a thickness of ~14 µm. In order to stabilize the suspensions of CuO or ZnO, respectively, a cationic polyelectrolyte polyethylenimine (PEI) is used. The polymer-modified nanoparticles are electrodeposited on the steel (cathode) surface at very low cathodic current density and following pH values: 1/CuO at pH 9.0, aiming to minimize the effect of aggregation in the suspension and dissolution of the CuO nanoparticles; 2/ZnO at pH 7.5 due to the dissolution of ZnO. Thereafter, ordinary zinc coating is electrodeposited on the CuO or ZnO coated low-carbon steel substrate from a zinc electrolyte at pH 4.5–5.0. The two-step approach described herein can be used for the preparation of hybrid coatings where preservation of particles functionality is required. The distribution of the nanoparticles on the steel surface and morphology of the hybrid coatings are studied by scanning electron microscopy. The thickness of the coatings is evaluated by a straight optical microscope and cross-sections. The protective properties of both systems are investigated in a model corrosive medium of 5% NaCl solution by application of potentiodynamic polarization (PDP) curves, open circuit potential (OCP), cyclic voltammetry (CVA), and polarization resistance (Rp) measurements. The results obtained allow us to conclude that both hybrid coatings with embedded polymer-modified CuO or ZnO nanoparticles ensure enhanced corrosion resistance and protective ability compared to the ordinary zinc.

Microstructure and Properties of Fe-Based Composite Coating by Plasma Jet Surface Metallurgy

2011 ◽  
Vol 179-180 ◽  
pp. 253-256
Author(s):  
Hao Chen ◽  
Jian Gao Yang ◽  
Mi Song Chen
Keyword(s):  
Steel Substrate ◽  
Composite Coatings ◽  
Low Carbon Steel ◽  
Plasma Jet ◽  
Optical Microscope ◽  
Al Alloy ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Metallurgical Bonding

The Fe-based composite coatings were formed by plasma jet surface metallurgy using Fe, C, W, Cr and Al alloy powders on the low carbon steel. The morphology, microstructure, interface structure and the distribution of the in situ particles in the coatings were observed with optical microscope, scanning electron microscope and x-ray diffraction analysis. The results show that metallurgical bonding is obtained between coating and substrate, and the microstructure of coatings is mainly composed of γ-Fe, (Fe,Cr,W,Nb)7C3 and AlFe particles which are synthesized in stiu, are dispersivly distributed in the coatings. The micro-hardness gradually increased from bottom to the top of the coating, the maximum is 986 Hv0.1, about 4 times larger than that of the steel substrate.

Corrosion study of low carbon steel under simulated geological disposal environments for HLW in China

2020 ◽  
Author(s):  
Junhua Dong
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Dissolved Oxygen ◽  
Open Circuit Potential ◽  
Steel Substrate ◽  
Low Carbon Steel ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Low Carbon ◽  
Simulated Groundwater

<p>In the multi-barrier system of HLW repository, overpack is the first barrier to isolate high-level radioactive nuclides from biosphere, and Low carbon steel has been considered to be a promising candidate material for manufacturing the oberpack due to its good mechanical performance and workability and weldability. However, during thousands of years of geological disposal, the corrosion resistance of low carbon steel and its corrosion evolution behavior are the first element that must be fully understood, because it determines the life cycle of the artificial barrier.</p><p>Conventional studies had suggested that the corrosion of low carbon steel under the deep geological environment was driven by hydrogen evolution reaction (HER) based on that the dissolved oxygen was completely depleted during the long term disposal. However, the residual oxygen content is a critical factor to determine the corrosion mode of cathodic reduction reaction. Thermodynamics data indicated that the initial ferrous corrosion products formed in the deaerated bicarbonate solution can be chemically oxidized into ferric substance by the trace content of dissolved oxygen, and the accumulated FeOOH as a cathodic depolarizer significantly increased the open circuit potential and enhanced the corrosion rate of the low carbon steel. Moreover, chloride and sulfate in the simulated groundwater can reduce the increase of open circuit potential but it still promotes the corrosion of the low carbon steel. As the environments contained aggressive anions and high concentration of dissolved oxygen, low carbon steel was prone to suffer from the localized corrosion and the corrosion rate was obviously increased. By alloying with some contents of Ni and Cu, the corrosion rate of low alloy steel was decreased by an order of magnitude and it was less prone to suffer from the localized corrosion.</p><p>Under the conditions of simulated groundwater with different content of GMZ bentonite，the bentonite colloidal particle layer attached to the surface of low carbon steel showed blocking effect on resisting oxygen diffusion to the steel substrate, which consequently decrease the further oxidation of ferrous to ferric substances and the corrosion rate of low carbon steel. However, the barrier performance of bentonite colloids would be deteriorated due to their coagulation caused by the ferrous ions dissolved from the steel substrate. High content of bentonite was beneficial to maintain and to prolong the stabilization of the barrier system. An equivalent circuit model which correlates with the interfacial structure between electrode substrate and rust and bentonite layer was proposed. The fitting results showed a very good match between the model and experimental data, and the evolution of the results was also in agreement with real changes.</p>

Corrosion protective performance of epoxy-amino branched polydimethylsiloxane hybrid coatings on carbon steel

2015 ◽  
Vol 62 (5) ◽  
pp. 334-340
Author(s):  
Rami Mohammad Suleiman
Keyword(s):  
Carbon Steel ◽  
Electrochemical Impedance ◽  
Protective Coatings ◽  
Steel Substrate ◽  
Sol Gel ◽  
Hybrid Coatings ◽  
Nacl Solution ◽  
Cerium Ammonium Nitrate ◽  
Content Type ◽  
Steel Panels

Purpose – The purpose of this paper was to prepare a hybrid organic/inorganic coating with interesting barrier properties against the corrosion of plain carbon steel sheets in 3.5 per cent NaCl solution. The search for replacing chromates in protective coatings has led to the development of hybrid sol-gel anticorrosive coatings. Appropriate functionalization can dramatically enhance the chemical durability and mechanical strength of these coatings. Design/methodology/approach – To prepare the targeted coating, 1,2-epoxybutane (EB) was mixed with 2 to 4 per cent aminoethylaminopropyl-methylsiloxane dimethylsiloxane (APDMS) copolymer and 1,6-diaminohexane. The above coating (EBAC) has been further mixed with three different corrosion inhibitors “Moly-white® 101-ED, Heucophos Zapp® and cerium ammonium nitrate”, yielding the coatings EBAC-M, EBAC-Z and EBAC-Ce, respectively. The corrosion characteristics of all coatings on the steel panels immersed in 3.5 per cent NaCl solution were obtained using different electrochemical methods such as electrochemical impedance spectroscopic and Tafel polarization measurements. Findings – The newly prepared coatings showed interesting protection properties for protecting the steel substrate against corrosion in chloride-containing media. Originality/value – The results provide a good approach for the modification of polydimethylsiloxane coatings using a simple organic modifier.

scholarly journals The Microstructure Properties of Ni-W Alloy Electrodeposition

2018 ◽  
Vol 21 (1) ◽  
pp. 82
Author(s):  
Mofeed A. Jaleel ◽  
Eilaf Z. Gurji
Keyword(s):  
Steel Substrate ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Solution Temperature ◽  
Major Influence ◽  
Deposition Condition ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Alloy Electrodeposition ◽  
Nickel Tungsten

The Electrodeposition process has been used to prepare Nickel-Tungsten alloys on low carbon steel substrate by using ammonical citrate bath. The influence of deposition condition by variation of current density (0.04-0.2 A/cm2) and solution temperature (60-70 °C), on the microstructure was studied. The optical microscope and the scanning electron microscopy (SEM) were used to study the morphology of the deposit while the energy dispersive spectroscopy (EDS) was used to approximate the composition, in addition to X-Ray diffraction examination. The results show that the current efficiency has the major influence on the tungsten content in the alloys due to the formation of ternary complex which reflected into the properties of the deposit. Keywords: 

scholarly journals Electrochemical Obtaining and Corrosion Behavior of Zinc-Polyaniline (Zn-PANI) Hybrid Coatings

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 487 ◽  
Author(s):  
Nelly Boshkova ◽  
Nadezhda Tabakova ◽  
Genoveva Atanassova ◽  
Nikolai Boshkov
Keyword(s):  
Photoelectron Spectroscopy ◽  
Zinc Coating ◽  
Low Carbon Steel ◽  
Open Circuit ◽  
Steel Plates ◽  
Hybrid Coatings ◽  
Low Carbon ◽  
Model Medium ◽  
X Ray ◽  
Before And After

Hybrid zinc-based coatings with embedded polyaniline (PANI) particles in the metal matrix are obtained in a one-step process via electrodeposition on low-carbon steel plates. The aim is directly to use the inhibitor properties of polyaniline for improved protection against corrosion in chloride containing medium (5% NaCl solution). PANI-particles (concentration of 0.025 g/L) are added to the starting zinc electrolyte in dispersed form—the latter being obtained via oxidation polymerization in the presence of stabilizers (polyvinyl pyrrolidone (PVP) or colloidal SiO2). Electrodeposition conditions are equal to those for obtaining an ordinary zinc coating. The surface morphology of the hybrid coatings before and after corrosion treatment in the model medium is characterized with SEM. The influence of the incorporated PANI/PVP- or PANI/SiO2-particles on the protective properties of the coatings is evaluated by the application of electrochemical (potentiodynamic polarization, open-circuit potential, polarization resistance, cyclic voltammetry) as well as X-ray based (X-ray diffraction and X-ray photoelectron spectroscopy) methods. A discussion and some conclusions about the reasons for the improved corrosion resistance and protective ability of the hybrid coatings in that model medium are proposed.

scholarly journals Characterization of Polyorganosilazane-Derived Hybrid Coatings for the Corrosion Protection of Mild Steel in Chloride Solution

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 680 ◽  
Author(s):  
Michele Fedel ◽  
Francisco Javier Rodríguez Gómez ◽  
Stefano Rossi ◽  
Flavio Deflorian
Keyword(s):  
Mild Steel ◽  
Corrosion Protection ◽  
Steel Substrate ◽  
Sol Gel ◽  
Low Carbon Steel ◽  
Hybrid Coatings ◽  
Low Carbon ◽  
Hybrid Layer ◽  
Minimum Thickness ◽  
Dry Film Thickness

Polysilazane (PSZ) have been used for many years as precursors for the development of ceramic materials. Recently, hydrocarbon-substituted polysilazane, which is called organopolysilazane (OPSZ), has been proposed as possible alternative to silanes for the corrosion protection of metals by the sol gel route. In this work, polymethyl(hydro)/polydimethylsilazane-derived coatings were deposited on low-carbon steel for corrosion protection purposes. The effect of the OPSZ precursor concentration (10–40 v/v %) in butyl-acetate on the final properties of the coatings was investigated. Coatings in the thickness range of 1 to 3.5 µm were obtained. The experimental results showed that the concentration of OPSZ in the solvent affects the structural properties as well as the dry film thickness of the hybrid layer. In particular, the network arrangement seems to be influenced by the dilution of the OPSZ precursors solution. The electrochemical characterization revealed that a minimum thickness of about 2 to 3 µm is needed to provide the mild steel substrate with enhanced corrosion protection properties compared to the bare substrate. Comparing the obtained results with literature data, it seems that OPSZs are a potential alternative to coatings derived from organisilicon precursors.

Corrosion protective performance of epoxy-amino branched polydimethylsiloxane hybrid coatings on carbon steel

2014 ◽  
Vol 61 (6) ◽  
pp. 423-430 ◽  
Author(s):  
Rami Mohammad Suleiman
Keyword(s):  
Carbon Steel ◽  
Electrochemical Impedance ◽  
Protective Coatings ◽  
Steel Substrate ◽  
Sol Gel ◽  
Hybrid Coatings ◽  
Nacl Solution ◽  
Cerium Ammonium Nitrate ◽  
Content Type ◽  
Steel Panels

Purpose – The purpose of this work was to prepare a hybrid organic/inorganic coating with interesting barrier properties against the corrosion of plain carbon steel sheets in 3.5 per cent NaCl solution. The search for replacing chromates in protective coatings has led to the development of hybrid sol-gel anticorrosive coatings. Appropriate functionalization can dramatically enhance the chemical durability and mechanical strength of these coatings. Design/methodology/approach – To prepare the targeted coating, 1,2-epoxybutane (EB) was mixed with 2-4 per cent aminoethylaminopropyl-methylsiloxane dimethylsiloxane copolymer and 1,6-diaminohexane. The above coating (EBAC) was further mixed with three different corrosion inhibitors “Moly-white® 101-ED, Hfucophos Zapp®” and Cerium Ammonium Nitrate, yielding the coatings (EBAC-M), (EBAC-Z) and (EABC-Ce), respectively. The corrosion characteristics of all coatings on carbon steel panels immersed in 3.5 per cent NaCl solution were obtained using different electrochemical methods such as electrochemical impedance spectroscopic and Tafel polarization measurements. Findings – The newly prepared coatings showed interesting properties for protecting the steel substrate against corrosion in chloride containing media. Originality/value – The results provide a good approach for the modification of polydimethylsiloxane coatings using a simple organic modifier.

Mechanical Adhesion and Pickling Behaviour of Thermal Oxide Scales on Hot-Rolled Low Carbon Steel Strips Produced by Different Finishing Temperatures

2011 ◽  
Vol 696 ◽  
pp. 170-175 ◽  
Author(s):  
Komsan Ngamkham ◽  
Satian Niltawach ◽  
Somrerk Chandra-ambhorn
Keyword(s):  
Carbon Steel ◽  
Steel Substrate ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Steel Strips ◽  
Thermal Oxide ◽  
Mechanical Adhesion ◽  
Hot Rolled

Hot-rolled low carbon steel strips were produced using two different finishing temperatures at 910 and 820 °C in an industrial hot-rolling line. Mechanical adhesion of scale on the steel substrate at 40 mm from the edge was investigated by tensile test. It was found that the strain initiating the first spallation of scale produced at higher finishing temperature was lower. Spallation ratio which is a spalled area of scale divided by the total area of scale examined under an optical microscope was steeper when the scale was produced at higher finishing temperature. The lower values of strain initiating the first spallation and the higher values of spallation ratio of scale formed both at higher finishing temperature were due to higher thickness of that scale. Pickling behaviour of the hot-rolled steels was investigated by immersing the studied steels in a 10%v/v HCl solution at 80 °C. X-ray diffraction (XRD) peak of hematite relative to that of iron decreased with pickling time and approached zero during pickling periods from 3 to 10 s, while magnetite-and-iron ratio gradually decreased and tended to be zero at longer pickling time. This might indicate the existence of hematite as the outermost layer of scale and subscale containing magnetite as the inner part.

scholarly journals Influence of the Laser Cladding Parameters on the Morphology, Wear and Corrosion Resistance of WC-Co/NiCrBSi Composite Coatings

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5583
Author(s):  
Iosif Hulka ◽  
Ion D. Uțu ◽  
Diana Avram ◽  
Mircea L. Dan ◽  
Alexandru Pascu ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Laser Cladding ◽  
Sliding Wear ◽  
Protective Coatings ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Low Carbon Steel ◽  
Thermal Spraying ◽  
Low Carbon ◽  
Wear And Corrosion

To enhance the sliding wear and corrosion behavior of steels with low carbon content, cermet composite coatings are usually deposited on their surface by various deposition processes. Laser cladding, compared to other deposition techniques such as electroplating, arc welding, and thermal spraying, has numerous advantages to produce such protective coatings. The paper presents the optimization of laser cladding deposition speed versus energy density in order to obtain WC-Co/NiCrBSi coatings with Ni-Al addition free of defects and reduced porosity deposited on low carbon steel substrate. The microstructure and chemical composition were investigated by SEM combined with EDX analysis while XRD was performed in order to examinate the phases within the coatings. In order to investigate the cladding speed influence on the coatings, hardness measurements, POD (pin on disk) wear tests and corrosion tests in 3.5% NaCl solution were carried out. The results showed that an optimal cladding speed has a crucial impact on the microstructure, composition, and hardness. It was found out that optimizing the cladding deposition speed proved to be effective in enhancing the sliding wear resistance and corrosion behavior by controlling the iron content within the coatings.

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