Uncoated Carbon Steel Research Articles

Facile fabrication of robust, multi-functional and superhydrophobic coatings with corrosion resistance and anti-icing performance

In this paper, a series of superhydrophobic coatings with varying n-SiO2 content were prepared using a simple one-step spray method. The coatings were characterized with SEM, XPS, electrochemical workstation, AFM, etc. The influence of n-SiO2 content on the micro-nanostructure of the coatings was investigated, as well as the elemental composition, the wettability, mechanical stability, chemical stability, and anti-icing performance. The results showed that as the n-SiO2 content increased, the wettability and anti-icing time of the coatings initially increased and then decreased. The optimal performance was achieved at an n-SiO2 content of 4.16 wt%, with a contact angle of 162.62°, a sliding angle of 4.17°, and an anti-icing time of 1095 s. Mechanical stability was improved with increasing n-SiO2 content, and the coatings lasted for 40 sandpaper abrasion cycles, 55 tape peeling cycles, and 31 icing/deicing cycles at 4.88 wt% of n-SiO2. The coatings demonstrated good chemical stability in neutral and acidic environments but failed in strongly alkaline conditions. Electrochemical tests revealed that the superhydrophobic coatings provided excellent protection, with the corrosion inhibition efficiency (η) of Q235 carbon steel reaching 99.99 % after coating compared to uncoated Q235 carbon steel.

Polyester-Based Coatings with a Metal Organic Framework: An Experimental Study for Corrosion Protection

Polyester coatings containing metal-organic framework (MOF) corrosion inhibitors were studied for their ability to protect carbon steel. The polyester coating was synthesized in the laboratory using microwave (MW) radiation to polycondense soy fatty acids, phthalic anhydride, and pentaerythritol-type polyols. The incorporation of these inhibitors into the polyester coating altered the behavior of the carbon steel, resulting in enhanced corrosion protection compared with uncoated carbon steel and polyester alone. Polyester with a 49% oil content, prepared using fatty acids from soybeans, phthalic anhydride, and pentaerythritol synthesized under microwave irradiation, and with a content of 3 mM Mg(GLY), exhibited a notable enhancement in the anticorrosive properties of the alkyd coating. The inhibition mechanism of corrosion was investigated through electrochemical impedance spectroscopy analysis.

Engineering defect concentration and morphology of green graphene for the development of hard and anticorrosive coating on carbon steel

In this study, sustainable waste agri biomass (WAB) was used to create defective green graphene (GGs) by physical, chemical, and thermal treatment at various temperature regimes (350 °C to 750 °C). The anti-corrosion performance of the GGs as reinforcement into an epoxy matrix was analyzed by electrochemical techniques (Tafel, EIS). The electrochemical results show the GG-400/EP composite coating was 93.9 % higher in corrosion resistance than uncoated carbon steel. The GG-400/EP composite coating shows improvement in surface roughness (25.35 %), hydrophobicity (64 %), and hardness (245 %). The post-corrosion analysis reveals that Well-dispersed GGs in the EP matrix create a "labyrinth effect," enhancing anticorrosion properties.WAB being a natural material has many inherent functionalities, some of which may not be consonant in delivering the desired coating property, and thus, the thermally treated WAB, that is here known as GGs, needs appropriate refinement. The addition of GGs , however, produced changes in the elastic moduli of the coating that provides a unique property enhancement- yet unreported in normal coatings.

Performance of Anticorrosive Paint Systems for Carbon Steel in the Antarctic Marine Environment.

This study evaluated the behavior of three paint systems exposed to the Antarctic marine environment for 45 months compared to a control of uncoated carbon steel with a determined corrosion rate. At the study site, all environmental conditions, solar radiation, and the concentration of environmental pollutants (Cl- and SO2) were evaluated. The paint systems differed in terms of the primer and top coat. Coated samples were studied before and after exposure. They were evaluated visually and using SEM to determine adhesion, abrasion, and contact angle; using the Evans X-Cut Tape Test; using ATR-FTIR spectroscopy to analyze the state of aging of the top layer; and using electrochemical impedance spectroscopy (EIS) for coat protection characterization. The corrosion rate obtained for steel was 85.64 µm year-1, which aligned with a C5 environmental corrosivity category. In general, the evaluation in the period studied showed the paint systems had good adhesion and resistance to delamination, without the presence of surface rust, and exhibited some loss of brightness, an increase in the abrasion index, and a decrease in the percentage of reflectance due to aging. EIS showed good protection capability of the three coating schemes. In general, this type of paint system has not previously been evaluated in an extreme environment after 45 months of exposure to the environment. The results showed that the best behavior was found for the system whose top layer was acrylic-aliphatic polyurethane.

Laser Cladding of Alloy 82 Powder for Corrosion Protection in Small Modular Reactors

There has been an increased demand for surface modification technologies to enhance corrosionresistance and wear-resistance. Among the representative surface coating technologies, laser cladding has attracted great attention because of its multiple advantages including low heat input, low dilution ratio, controllable clad height, etc. Recently, laser cladding has been considered as a surface coating technology for the next-generation small modular reactor, although submerged arc welding was utilized for the 3rd generation nuclear reactor. Cobalt-free materials are required as cladding materials in the nuclear reactor because cobalt has a long half-life. In this work, nickel based cobalt-free Alloy 82 powder was utilized. The main experimental parameters for laser cladding were intensively investigated by varying laser power, scan speed, powder supply, carrier and shield gas, overlap ratio, etc. Additionally, cross-sectional area calculation and EPMA analysis were carried out to examine the dilution ratio. Mechanical properties were also evaluated using microhardness tests and wear tests at high temperatures. Finally, corrosion tests were performed to compare a laser clad surface with an uncoated carbon steel surface. Our study indicates that the laser cladding using Alloy 82 powder is feasible for corrosion protection in next-generation small modular reactors.

New protective coatings against liquid zinc corrosion

Hot dip galvanizing is a surface treatment used to form a corrosion-resistant layer on the surface of steel by dipping it in a liquid zinc bath. However, a lot of structures used for hanging or containing the parts during the process are made of steel and suffer from liquid zinc corrosion. Furthermore, Fe–Zn intermetallics formed on the surface induce an additional pickling and zinc consummation, therefore generating supplementary economic and environmental costs. In this article, two Fe-Cr-Ni-Si coatings synthetized by the slurry process on carbon steel (C22) were characterized by XRD, EDX, EPMA and EBSD analyses. Their corrosion protective properties were studied in the process imitating cyclic batch galvanizing and compared to those of uncoated carbon steel (C22) and stainless steel (316 L). The coatings were verified to be more efficient than the 316 L steel usually used for this application. After 9 cycles of no weight loss, molten zinc corrosion was linear and the same for Fe-Cr-Ni-Si coatings as for the stainless steel.

Use of waste to wealth process derived sustainable silica-rich graphene analogues to provide enhanced corrosion resistance properties for coatings on carbon steel, exposed to marine environments

Here, we have demonstrated the effects of the application of silica-rich green-graphene analogues (SRGA) mixed epoxy coating on carbon steel in terms of corrosion resistance and other properties. The anticorrosion performance of SRGA/EP coatings with various concentrations (0.05 wt%, 0.1 wt%, and 0.5 wt% SRGA) on carbon steel in 3.5 wt% NaCl was investigated using the potentiodynamic polarization technique (PDP) and electrochemical impedance spectroscopy (EIS). The surface morphologies of pure epoxy (EP) and SRGA/EP-coated specimens were investigated by scanning electron microscopy (SEM). Incorporating the SRGA/EP coating approach on carbon steel pipes can improve the thermal stability, hydrophobicity, and surface finish of the produced composite coatings. The corrosion inhibition efficiency of 0.1 wt% SRGA/EP-coated carbon steel specimens was 99 % higher than uncoated carbon steel specimens. The thermal stability of 0.1 wt% SRGA/EP coating was improved by 5–7 % compared to pure EP coating. The synthesized SRGA/EP coating showed acceptable uniform distribution on the carbon steel. The average roughness (Ra) of SRGA/EP-coated carbon steel was 67.8 % lower compared to the uncoated ones and 37.3 % lower than the pure EP-coated carbon steel specimens. These materials, derived from green processes can be suitable replacements for traditional toxic chemicals employed for corrosion-resistant coating in carbon steel surfaces of water pipes. Apart from the benefits of use in performance, SRGA application can help environmental -social-governance (ESG) compliance for the paints and coatings industry.

Calcareous Deposits Formed Under Long‐Term In Situ Cathodic Protection Tests

AbstractThe calcareous deposits formed under commonly applied cathodic protection techniques on coated and uncoated carbon steel samples immersed in Guanabara Bay for 150 days, simulating ships and pipelines, were investigated. Potentials were monitored throughout the analysis, and deposits were examined by visual inspection, optical microscopy, energy‐dispersive X‐ray spectroscopy, and X‐ray diffraction. Beyond calcite, aragonite, and brucite, which are crystals commonly reported in laboratory tests or under confined space conditions, herein, also calcite‐II and calcite‐III were identified as intermediate crystalline structures. Furthermore, it was demonstrated that biological activity also plays an important role, forming calcareous tubular structures within the deposit.

Enhanced corrosion inhibition of low carbon steel in aqueous sodium chloride employing sol–gel-based hybrid silanol coatings

The anti-corrosion properties of sol–gel-based hybrid silanol coatings incorporated with span tea leaves extract employed on low carbon steel in saline solution was explored by electrochemical and surface analyses. Hybrid sol–gel matrices were prepared by copolymerizing tetraethyl orthosilicate (TEOS) and 3-aminopropyltriethoxysilane (APTES). Corrosion protective hybrid sol–gel coatings were dip-coated on low carbon steel substrates and sintered to ensure the formation of metallo-siloxane bonds. Inhibition efficiency of 85.66% was achieved with the doping concentration of 75 ppm of water extract into hybrid sol–gel at 30 °C. Polarisation studies demonstrated that the hybrid coatings incorporated with water extract of span tea leaves operate as a mixed-type inhibitor. The Nyquist impedance plots depicted that on increasing the concentration of span tea leaves extract, charge transfer resistance (Rct) increased, and double-layer constant phase element (CPEdl) decreased. A comparison of the corrosion resistance of the coated and uncoated low carbon steel substrates was presented. Electrochemical noise analysis substantiated that the optimum corrosion-resistant coating formulation endured a much lower current noise fluctuation. Moreover, wettability analysis established the hydrophobic nature of the optimum corrosion protective coating.

Corrosion resistance evaluation of carbon steel plates protected by zirconium and titanium nanoceramic coatings

Metal surface pre-treatment is a known process and is used to increase corrosion performance as well as improve adhesion between the substrate and the paint layer. The present paper evaluated the corrosion resistance of carbon steel before and after treatment with nanoceramic coatings. The comparison was between a pure zirconia nanoceramic compound (Bonderite NT-1), with the addition of a dispersant (polyacrylic acid) and another nanoceramic coating developed from titanium oxide. Additionally, salt spray, open circuit potential (OCP), polarization and impedance tests were performed to obtain a methodology to quantitatively assess the quality of protection. The zirconia coating presented superior characteristics than the corrosion protection. The corrosion potential of this coating was about twice as low as the others. The addition of dispersant produced no significant improvements in corrosion resistance and was similar to uncoated carbon steel, possibly due to the high concentration used.

Impressed Current Cathodic Protection of Low Carbon Steel in Conjunction with Conducting Polyaniline based Paint Coating

Epoxy, Fusion bonded epoxy and conducting polyaniline based paints were applied on low carbon steel sample. Conducting polyaniline and conducting polyaniline based paint was characterized by UV-visible absorption spectroscopy and scanning electron microscopy respectively. Cathodic polarisation was used to determine cathodic protection potential range of the uncoated and painted low carbon steel samples dipped in 3.5% NaCl. Cathodic impressed current range was found out using galvanostatic technique and used to impart cathodic protection to non coated and painted samples. Iron loss of uncoated and painted samples without cathodic protection and under cathodic protection was measured using spectrophotometry. It was found that conducting polyaniline based paint exhibits negligible iron loss ~0.06 ppm in 3.5% NaCl solution under impressed current cathodic protection. Conducting polyaniline based paint can be used in association with impressed current technique to protect low carbon steel cathodically in neutral medium. However, conducting polyaniline, as a pigment, becomes less effective in presence of coating defects due to exposure of the metallic surface to the electrolyte.

Experimental investigation on application of industrial coatings for prevention of asphaltene deposition in the well-string

Asphaltene deposition in the wellbore during natural depletion and EOR processes causes severe problems and increases the cost of the incremental oil recovery. Investigation of coatings as a preventive approach for operational problems during well production seems mandatory due to economic, environmental and technical limitations involved in mechanical and chemical treatment approaches. In this work, the anti-asphaltene performance of different coatings namely epoxy resin, polyurethane, phosphate, and two fluoropolymers (PTFE and PFA) was investigated by using a flow loop experimental setup. The wettability characteristics of the coated coupons were also studied by contact angle measurements to explore the correlation between asphaltene adherence tendency and wettability of the treated surfaces. Experimental results showed that despite the hydrophilicity of carbon steel, an intense increasing trend in asphaltene deposition occurred due to intrinsically high surface energy of carbon steel. An anti-asphaltene deposition ratio (Raa) was defined to describe the anti-stick performance of different coatings compared to the uncoated carbon steel. It was observed that hydrophobic polyurethane and epoxy resin coatings showed weak anti-asphaltene performance with low Raa values where they have reduced asphaltene deposition 10% and 48.34%, respectively. Super-hydrophilic phosphate coating reduced the asphaltene deposition by 91.25% via formation of a water film on the coated surface. Finally, the fluoropolymer coatings showed the best performance among investigated samples by anti-asphaltene deposition ratios of 99.89% and 99.94%. The low surface energy of these coatings introduces them as non-reactive surfaces compared to other coatings, hence accepting much less asphaltene deposition.

A Method for Estimating Time-Dependent Corrosion Depth of Carbon and Weathering Steel Using an Atmospheric Corrosion Monitor Sensor.

In this study, a time-dependent corrosion depth estimation method using atmospheric corrosion monitor (ACM) sensor data to evaluate time-dependent corrosion behaviors is proposed. For the time-dependent corrosion depth estimation of uncoated carbon steel and weathering steel, acceleration corrosion tests were conducted in salt-spray corrosion environments and evaluated with a corrosion damage estimation method using ACM sensing data and corrosion loss data of the tested steel specimens. To estimate the time-dependent corrosion depth using corrosion current by an ACM sensor, the relationship between the mean corrosion depth calculated from the weight loss method and the corrosion current was evaluated. The mean corrosion depth was estimated by calculating the corrosion current and evaluating the relationship between the mean corrosion depth and corrosion current during the expected period. From the test and estimation results, the corrosion current demonstrated a good linear correlation with the mean corrosion depth of carbon steel and weathering. The calculated mean corrosion depth is nearly the same as that of the tested specimen, which can be well used to estimate corrosion rate for the uncoated carbon steel and weathering steel.

Investigations on Dry Sliding Wear and Corrosion Resistance of Thermal Sprayed Molybdenum Coatings

This paper aims to investigate the characteristics of molybdenum thermal sprayed coatings deposited on 1.0570 steel substrate and compare them with the characteristics of the uncoated carbon steel (1.0570), respectively alloyed steels (1.7219 and 1.6582), which are currently used for similar applications, such as parts and structural components used at temperatures down to -100°C, aircraft, terrestrial transportation and other industries. The Mo coating deposition was performed by wire metallization and aimed to increase the wear and corrosion resistance of steels typically applied in railway transportation industry. The microhardness, wear behaviour and corrosion resistance have been investigated for all the presented materials. Molybdenum coatings deposited by wire metallization technique possess superior frictional behaviour due to the formation of an oxide tribo-film. Therefore, the friction coefficient of the presently investigated Mo coatings reached a value of 0.65, correlated with a low wear rate of about 0.65·10-5 mm3 N-1 m-1. The porosity degree of the Mo coatings was found to be around 3.50%, a common value for this type of coatings. Microhardness average value of Mo coating was 480 HV0.3 and the corrosion behaviour was found to be superior in comparison to the other materials, exhibiting an inclination to passivation at around 300 mV.

Characterization and properties of plasma electrolytic oxidation coating on low carbon steel fabricated from aluminate electrolyte

Plasma electrolytic oxidation (PEO) coating was prepared from aluminate electrolyte on low carbon steel. The structure, composition, microhardness, anti-wear and anti-corrosion properties of the PEO coating were explored. The results show that the PEO coating possesses a uniform and dense structure and is mainly composed of α-Al2O3 as well as some γ-Al2O3 and Fe3O4. The PEO coating exhibits lower friction coefficient and wear rate than that of uncoated low carbon steel under dry sliding condition. The corrosion potential of coated sample shifts toward positive direction by 380 mV and the corrosion current density decreases by 2 orders of magnitude. Therefore, the PEO coating prepared from aluminate electrolyte can offer a good protection to low carbon steel from wear and corrosion.

Super-Hydrophobic Green Corrosion Inhibitor On Carbon Steel

There are many examples of organic coatings used for corrosion protection. In particular, hydrophobic and super-hydrophobic coatings are shown to give good protection because of their enhanced ability to slow down transport of water and ions through the coating. The purpose of this research is to develop water repellent coating to avoid direct contact between metal and environment corrosive and mitigate corrosion attack at pipeline system. This water repellent characteristic on super-hydrophobic coating was coated by electrodeposition method. Wettability of carbon steel with super-hydrophobic coating (cerium chloride and myristic acid) and oxidized surface was investigated through contact angle and inhibitor performance test. The inhibitor performance was studied in 25% tannin acid corrosion test at 30°C and 3.5% sodium chloride (NaCl). The water contact angle test was determined by placing a 4-μL water droplet of distilled water. It shows that the wettability of contact angle super-hydrophobic with an angle of 151.60° at zero minute can be classified as super-hydrophobic characteristic. By added tannin acid as inhibitor the corrosion protection on carbon steel becomes more consistent. This reveals that the ability of the coating to withstand with the corrosion attack in the seawater at different period of immersions. The results elucidate that the weight loss increased as the time of exposure increased. However, the corrosion rates for uncoated carbon steel is high compared to coated carbon steel. As a conclusion, from both samples it can be seen that the coated carbon steel has less corrosion rated compared to uncoated carbon steel and addition of inhibitor to the seawater provides more protection to resist corrosion attack on carbon steel.

Anodic Oxidation of Carbon Steel at High Current Densities and Investigation of Its Corrosion Behavior

This work aims at studying the influence of high current densities on the anodization of carbon steel. Anodic protective coatings were prepared on carbon steel at current densities of 100, 125, and 150 A/dm2 followed by a final heat treatment. Coatings microstructures and morphologies were analyzed using X-ray diffraction (XRD) and scanning electron microscope (SEM). The corrosion resistance of the uncoated carbon steel substrate and the anodic coatings were evaluated in 3.5 wt pct NaCl solution through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The results showed that the anodic oxide coatings which were prepared at higher current densities had thicker coatings as a result of a higher anodic forming voltage. Therefore, the anodized coatings showed better anti-corrosion properties compared to those obtained at lower current densities and the base metal.

Practical Method for Estimating Time-Dependent Corrosion Depth of Uncoated Carbon Steel Plates under Various Atmospheric Environmental Conditions Using Fe/Ag Galvanic Couple Corrosion Sensor

In this research, an evaluation method for the time-dependent corrosion depth of uncoated structural steel plates using an Fe/Ag galvanic couple atmospheric corrosion monitoring (ACM)-type sensor was proposed. This method was focused on environments with and without effects of rainfall and airborne sea salt. Atmospheric exposure tests were carried out on the uncoated carbon steel plates in four sites in which the environments varied widely as a function of rainfall and airborne sea salt. In addition to this, the corrosive environments of the skyward-and groundward-facing surfaces of the plates were monitored using the ACM sensors.

Protection of carbon steel against molten aluminum attack and high temperature corrosion using high velocity oxygen-fuel WC–Co coatings

Cermet coatings of WC–17Co were thermally sprayed on carbon steel substrates with 0.4wt.% C using high velocity oxygen-fuel. The main goal of the investigation was the protection of carbon steel substrates against the attack in contact with molten aluminum using WC–Co coatings. Different spraying conditions were used and the optimal coating (226μm thickness) was characterized by SEM, XRD, Raman spectroscopy, micro-hardness tests and 3D optical profilometry in order to determine thickness, porosity, chemical composition, mechanical properties and surface roughness. Pull-off adhesion tests were conducted to evaluate the adhesion between coatings and substrate, and thermal cycling tests were also developed. The coated steel substrates were immersed in molten aluminum at different times (1, 2, 5 and 24h), and the resistance of the coatings to the attack of the molten aluminum alloy was studied. It was observed that the WC–Co was an effective physical barrier against molten aluminum penetration. Just after 2h of immersion, the uncoated carbon steel suffered aggressive attack by the liquid aluminum, which penetrated and cracked it. Conversely, the coated steel was unaffected after 24h of immersion due to the protection of the WC–Co coating, which suffered the liquid metal penetration only in the outer 35μm using 700°C as the higher temperature. The effectiveness of the WC–Co coating to protect carbon steel substrates against thermal fatigue deterioration and attack by molten aluminum was proved.

Dissimilar metal laser spot joining of steel to aluminium in conduction mode

Dissimilar joining of thin (∼1 mm) 6111-T4 aluminium alloy and DC04 uncoated low carbon steel used in automobile structures was carried out using laser spot joining in conduction mode. Two sets of experiments were carried out, using copper and aluminium backing bars, respectively. The welds were produced in overlap configuration with steel on the top. The steel surface was irradiated by the laser, and the heat was conducted through the steel into the aluminium. Temperature at the interface was controlled using the fundamental laser energy parameters so that aluminium melts and wets the steel surface. Reaction between the two metallic alloys resulted in the formation of intermetallic compounds (IMC). The formation pattern of IMC was dependent on the temperature profile and the distribution across the interface and was thicker in the centre of the weld and thinner near the edges. The stoichiometry of the IMC formed was varied across the layer and was principally composed of two different layers of Fe2Al5 and FeAl3. Micro hardness tests were carried out to characterise the IMC layer. Mechanical shear tensile tests showed a maximum joint shear strength of up to 68 % of the shear strength of the aluminium alloy.