Corrosion Of Coatings Research Articles

Developments on friction surfaced coatings for corrosion, wear-resistant and composite

Friction surfacing is the most recent technology applied in surface engineering for developing surface materials. It is a solid-state technique employed to coat one material over another material in order to reconstruct the worn-out parts, to enhance protection from ware and corrosion, to develop mechanical features and composite materials.This is an environmentally-safe process in which a consumable rod is deformed plastically and forms a deposit of viscoelastic material over the substrate. The thickness and properties of the layer can be controlled by the rotational speed, axial downwards force, horizontal motion, time and tilt angle. Different materials have been taken in friction surfacing for deposition. The friction surfaced coating is also modified in different way according to requirement. Friction surfacing has been significantly applied to industrial applications. This paper reviews thoroughly the properties and microstructure of friction surfaced coating using different operating parameters and processes, focusing alternative technology on future research.

Unravelling the impact of palladium on ruthenium-induced corrosion of SiC coatings in TRISO particles

Ru and Pd are fission products released through SiC layer in TRISO fuel at high temperature. This study investigates the corrosion behaviour of Ru-Pd on SiC layers of tri-structural isotropic (TRISO) particles. Specifically, it explores the effects of Pd (strongly reactive FP) on Ru (weakly reactive FP)-induced corrosion. In Pd-Ru/SiC systems, a Ru-Pd-Si liquid phase forms at high temperatures even with minimal Pd, accelerating corrosion along SiC grain boundaries. Comparing Pd’s role in Ru/SiC and Ag/SiC systems underscores the importance of liquid phases in FP migration. A novel approach is proposed for predicting the corrosion effects of multiple FPs on SiC through enthalpic interaction analysis.

Exploring wear, corrosion, and microstructure in PEO coatings via laser surface treatments on aluminum substrates

The inadequate resistance to corrosion and wear of Al-based alloys is a major hindrance to their extensive use. Plasma electrolytic oxidation (PEO), a common and efficient coating technique, creates an oxide coating similar to ceramic on the surface of Al-based alloys, thereby improving their ability to withstand corrosion and wear. Studies have shown that PEO treatment can significantly enhance the short-term corrosion and wear resistance of Al-based alloys. To improve the long-term corrosion resistance of PEO coatings, researchers are now exploring the combination of laser processes with the PEO process. Laser processing is a simple yet efficient technique known for its flexibility, precision, and control. Various laser procedures are recognized for their ability to improve the resistance to wear and corrosion of PEO coatings applied on Al substrates and their alloys. Laser melting procedures have the capability to standardize and modify the microstructure of aluminum-based alloys. This review focuses on enhancing the anti-corrosion and anti-wear properties of aluminum alloys through the integration of laser surface treatments with PEO technology.

Optimization of pulse electrodeposition parameters for enhanced resistance to corrosion and hydrogen permeation of zinc coatings

Corrosion and hydrogen permeation resistance of pulse electrodeposited Zn coatings were correlated with coating micro-texture and strain. The maximum and minimum corrosion resistance were noted for D6F75 (duty cycle 60; frequency 75 Hz) and D8F25 (duty cycle 80; frequency 25 Hz), respectively. The D6F75 coating exhibited a higher fraction of low-energy low-angle grain boundaries (LAGBs) and a preferred texture of (31¯2¯1) whereas the D8F25 coating exhibited comparatively low LAGBs fractions and(21¯1¯0) orientation. High resistance to hydrogen permeation exhibited by the D6F75 coating was attributed to hydrogen trapping within the coating, which reduced the micro-strain within the coating and diminished the hydrogen concentration gradient, thereby promoting greater surface recombination.

Hydrothermal preparation of magnesium alloy surface composite coatings and its performance research

Magnesium alloys have great potential for industrial and aerospace applications due to their low density and high strength. Aiming at its defects of poor corrosion resistance and susceptibility to galvanic coupling corrosion in metal coatings, a composite coating was prepared on the surface of AZ91D magnesium alloy by the hydrothermal method. Scanning electron microscope, x-ray diffraction, and x-ray photoelectron spectroscopy were used to characterize the surface micromorphology, phase composition, and elemental valence and evaluate the adhesion of the coating to the substrate by the ASTM D3359-09 test standard. Electrochemical experiments were done in a 3.5% NaCl solution. The results show that there are nanoscale dense granular structures on the surface of the samples, and the main components of the coatings are Mg(OH)2, Al2O3, and MgSiO3. ASTM grade 4B is between coating and substrate. The corrosion rate of the best sample was reduced by a factor of 238.96 compared to the substrate, and the corrosion current density was reduced by two orders of magnitude. The corrosion rate and corrosion current of the samples after repeated friction did not change much compared with those before friction, which proved that the composite coating had better corrosion resistance and friction stability.

Wear, corrosion and cavitation erosion behavior of WC-reinforced FeCrNiMnAl ceramic-high entropy alloy composite coatings by laser cladding

FeCrNiMnAl/WC ceramic-high entropy alloy (HEA) composite coatings with various WC content are prepared on 304 stainless steel (304 SS) by laser cladding (LC). Experimental results show that residual tensile stress of coatings increases with the addition of WC content, and excessive addition of WC leads to cracking in 15WC and 20WC. All coatings are composed of BCC and WC duplex, and the addition of WC particles significantly refines grain size of the coatings. Compared with FeCrNiMnAl HEA coating, the coatings with WC addition exhibit improving mechanical properties and wear resistance due to the combined effect of multiple strengthening mechanisms. Among the tested coatings, 10WC exhibits the highest cavitation erosion (CE) resistance due to its excellent mechanical properties and corrosion resistance.

Influence of Ni content on electrochemical corrosion and tribological behavior of Cu-10Sn coatings by laser cladding

In this work, Cu-10Sn-xNi (x = 0, 3, 6, 9, and 12 wt%) alloy coatings were prepared using laser cladding technology. The influence of Ni content on the phase composition, microstructure, crystallographic characteristics, microhardness, electrochemical corrosion, dry sliding wear and corrosive wear behavior of the coatings were studied. The results indicated that the coatings formed good metallurgical bond with the substrate. The coatings were composed primarily of the α-Cu matrix and small γ precipitates. The Ni element effectively reduced component segregation, and with the increased of Ni content, the grain size in the coating was significantly refined, resulting in fine equiaxed grains. Under the effect of fine grain strengthening, the Cu-10Sn-12Ni (C12NS) coating achieved a higher microhardness of approximately 222.9 ± 5.3 HV0.2. In the electrochemical corrosion test, the increased in the number of grain boundaries significantly reduced the corrosion resistance of the Cu-10Sn-xNi coatings. The Cu-10Sn-6Ni (C6NS) coating exhibited excellent corrosion resistance, with an Icorr of only 1.37 μA/cm2. The results of the dry sliding wear test showed that under the influence of the hardness gradient between the hard precipitate phase and the soft matrix of the coating, the C6NS coating achieved satisfactory wear resistance with a specific wear rate of 3.30 × 104 μm3/Nm. Meanwhile, due to the good corrosive resistance, the C6NS coating showed the best tribological performance in 3.5 wt% NaCl environment, and the specific wear rate was 1.58 × 104 μm3/Nm.

High-temperature aqueous corrosion of MO–Na2O–B2O3–SiO2 glass and glass-ceramic coatings on metallic substrates: Effect of alkaline earth metals M2+= {Ca2+, Sr2+, Ba2+}

This investigation aims to assess the impact of 2 A alkaline-earth oxides on the alteration of glass/glass-ceramic coatings on steel under conditions of exposure to hot water. Experiments involved integrating CaO, SrO, and BaO into sodium-borosilicate glass systems after that a melting-quenching process to obtain frits. Coated and sinter-crystallized samples denoted as GC-Ca, GC-Sr, and GCC-Ba were exposed to hot aqueous corrosion according to DIN 4753–3 at 95 °C, which determined weight loss after 42 days. ICP-MS analyzed aqueous solutions for element leaching. Results indicated that glass-ceramic coatings (GCC-Ba) outperformed glass coating(GC-Ca, GC-Sr). GCC-Ba demonstrated enhanced stability, attributed to limited ion exchange and diffusion at high temperatures, enhancing corrosion resistance, supported by sanbornite crystal phase presence. Total element release by ICP-MS and 42 days of hot water corrosion coatings' weight loss after 42-day corrosion test lined up: GC-Sr > GC-Ca > GCC-Ba.

Corrosion Resistance of Coatings Based on Chromium and Aluminum of Titanium Alloy Ti-6Al-4V.

Improvement of wear, corrosion, and heat-resistant properties of coatings to expand the operational capabilities of metals and alloys is an urgent problem for modern enterprises. Diffusion titanium, chromium, and aluminum-based coatings are widely used to solve this challenge. The article aims to obtain the corrosion-electrochemical properties and increase the microhardness of the obtained coatings compared with the initial Ti-6Al-4V alloy. For this purpose, corrosion resistance, massometric tests, and microstructural analysis were applied, considering various aggressive environments (acids, sodium carbonate, and hydrogen peroxide) at different concentrations, treatment temperatures, and saturation times. As a result, corrosion rates, polarization curves, and X-ray microstructures of the uncoated and coated Ti-6Al-4V titanium alloy samples were obtained. Histograms of corrosion inhibition ratio for the chromium-aluminum coatings in various environments were discussed. Overall, the microhardness of the obtained coatings was increased 2.3 times compared with the initial Ti-6Al-4V alloy. The corrosion-resistant chromaluminizing alloy in aqueous solutions of organic acids and hydrogen peroxide was recommended for practical application in conditions of exposure to titanium products.

Corrosion of irradiated NbMoVCr coatings in lead-bismuth eutectic

NbMoVCr multi-principal element alloy (MPEA) coatings were irradiated by 6 MeV Au-ions at room-temperature and 550 ℃ to the peak irradiation doses of 20 dpa and 80 dpa. Then the effect of irradiation on corrosion of coatings in liquid lead-bismuth eutectic (LBE) was investigated. By comparing the microstructure of the surface oxide film and grain boundary corrosion region in the irradiated and unirradiated coatings, it is revealed that Au-ions irradiation promotes both the overall corrosion and intergranular corrosion of NbMoVCr coatings, which is attributed to the irradiation-induced defects as well as the desegregation of V elements at grain boundaries.

A novel siloxene@MoS2 heterostructure for improving the wear and corrosion resistance performance of epoxy coatings

Siloxene (Sic) flakes are two-dimensional silicon-based materials that have been extensively investigated in the domains of batteries, supercapacitors, and electrocatalysis, with essentially no research in the domain of corrosion and wear resistance performance of metal coatings. In this study, Sic sheets were prepared through topological chemical exfoliation and applied to epoxy (EP) resin systems for the first time. The effects of Sic sheets on the corrosion and wear resistance performance of the composite coatings were explored. To improve the enhancement effect of Sic on the tribological properties and corrosion resistance of the composite coatings, molybdenum disulfide (MoS2), which exerts a self-lubricating effect and an enhanced interfacial effect, was grown on the surface of Sic using a hydrothermal method. The corrosion resistance and tribological properties of the prepared composite coatings were characterized through electrochemical impedance spectroscopy, polarization curve analysis, and friction and wear tests. The results indicated that the composite coating containing 0.75 wt% siloxene@MoS2 (Sic@MS) has the best corrosion resistance and tribological properties. Compared with the pure EP coating, the wear rate of the Sic@MS coating with the aforementioned concentration was reduced by 67 %. Furthermore, the impedance module value at 0.01 Hz was increased by three orders of magnitude and the corrosion current density was reduced by three orders of magnitude after 60 days of immersion in NaCl solution. The above results provide a new idea for the application of Sic materials.

Carbon dot enhanced electrodeposited coatings for advanced early-stage corrosion sensing

This work explores a novel approach for metal corrosion by integrating carbon dots (CDs) into electrodeposited (ED) coatings. We detail the synthesis and properties of CDs, making them suitable for corrosion detection. Characterization techniques like Fourier Transform Infrared Spectroscopy (FTIR), Scanning electron microscope (SEM), Energy Dispersive X-ray Analysis (EDX), Fluorescent Microscopy and Photoluminescence Spectroscopy (PL).A Design of Experiment (DOE) optimized parameters like CD concentration, curing temperature, and voltage for improved coating performance. The optimized conditions (0.4 wt% M-CDots, 165 °C curing, and 36.2 V) resulted in enhanced adhesion and corrosion resistance.CD-infused coatings demonstrated superior adhesion and mechanical stability compared to controls. Electrochemical tests confirmed a 10 % improvement in corrosion resistance and PL study demonstrated an approximately 60 % enhancement in emission intensity. The adhesion was not affected by introducing carbon dots to the coating. Monitoring the onset of metal corrosion on samples in salt spray cabinets was achieved through the use of a UV source. The photoluminescence of M-CDs offered real-time, non-destructive monitoring of early-stage corrosion through quenching in the presence of exposed metal surfaces.This research presents a significant advancement by integrating CD-based sensing into corrosion-resistant coatings, holding promise for various industries and leading to improved safety, reduced maintenance costs, and extended equipment lifespans. Notably, the biocompatible and disposable nature of CD-based sensors further enhances their practical application.

Study on Antibacterial Durability of Waterproof Coatings with Different Base Materials

Microbial corrosion of waterproof coatings causes structural damage to buildings and renovation materials and severely threatens human health. In practical applications, coatings with different base materials show different durabilities to external environmental influences. There is little literature on the antimicrobial durability performance of waterproof coatings. Therefore, this paper selected four standard waterproofing coatings, including polyurethane coatings, cement-based coatings, asphalt-modified polymer coatings, and polymer emulsion coatings, as the main body of this study. Their antimicrobial abilities against Gram-negative Escherichia coli, Gram-positive Staphylococcus aureus, Candida albicans, and mold were tested after experiencing three kinds of harsh environments: Ultraviolet ray (UV), water immersion, and low temperature. The results show that the extreme climates significantly reduced the ability of the four coatings to resist mold, and the highest growth rate of bacteria was 54.64%. Under UV conditions, the polymer emulsion coatings were significantly more resistant to Candida albicans, and the optical density of the bacterial liquid showed a negative growth trend. The microstructural integrity of the polymer emulsion coatings was found to be damaged by Scanning Electron Microscope (SEM) observation. This work improves the durability application research on these coatings and provides a valuable reference for developing new environmentally friendly, antibacterial, and anticorrosive waterproof coatings.

Investigation of the Corrosion and Tribological Properties of WC-Co Tools Hardened with PVD Coatings in Solid Oak Wood Processing

Corrosion and friction coefficient tests were performed on solid oak wood machined with hard-metal woodworking tools coated with PVD coatings (AlCrN, AlTiN, TiAlN, TiCN and CrN). The tannic acid attacks the carbide more intensively than the PVD coatings. During cutting, corrosion spreads on the cutting edge of the cutter due to mechanical action, which dissolves the cobalt binder of the hard-metal and causes the carbide grains to flake off. After 80 min of contact with the wood, the cobalt content decreases from 3.53 to 1.74%. Depending on the PVD coating material, cracks of 4 to 40 µm in width appear after 120 min (9000 m cutting path). After 120 min of machining, wear, corrosion effects and the influence of corrosion on the coefficients of friction were evaluated for tools with and without PVD coatings. TiCN is the most sensitive to corrosion, while AlCrN and CrN coatings are the least sensitive, with the AlTiN coating being the most affected under real cutting conditions (with mechanical + thermal + corrosion effects) and the tools with CrN and AlCrN coatings being the least affected. Corrosion affects the hard-metal and PVD coatings and reduces the coefficient of friction. The angle between the directions of sliding and sharpening of the cutting edge sharpening significantly influences this parameter. The coefficient of friction of hard-metal WC-Co and PVD coatings is higher in the parallel machining direction than in the perpendicular machining direction and ranges from 16.03% (WC-Co) to 44.8% (AlTiN). The coefficient of friction of hard-metal WC-Co decreases by 5.13% before and after exposure to tannic acid, while the corrosion of PVD coatings reduces it by 4.13% (CrN) to 26.7% (TiAlN).

Electrochemical corrosion and tribocorrosion behavior of CrN and CrAlN coatings in artificial seawater

AbstractThis study investigated the corrosion and tribocorrosion behavior of CrN and CrAlN coatings deposited on steel through direct current magnetron sputtering. Additionally, the effects of Al addition on the microstructure, corrosion inhibition, and tribocorrosion behavior of CrN coatings were evaluated. Compared with the CrN coating, the CrAlN coating exhibited a denser columnar crystal structure and a higher hardness of 23.8 GPa. The CrAlN coating reacted with water to form Al2O3 and Cr2O3 films, which enhanced its corrosion resistance. Moreover, the addition of Al enhanced the wear resistance of the CrN coating and reduced the material loss due to corrosion, wear, and their synergistic effects. The CrAlN coating exhibited a low corrosion current density of 1.14 × 10−8 A/cm2, indicating a 92% reduction compared with the CrN coating. Furthermore, under either open circuit potential or anodic accelerated tribocorrosion conditions, the CrAlN coating featured significantly lower total material loss and synergistic material loss than the CrN coating, demonstrating higher corrosion and tribocorrosion protection.

Corrosion of Zinc Cold Spray Coatings in a Wet Sweet and Sour Gas Environment

Internal corrosion is a problem for steel pipelines transporting natural gas or CO2 containing water and partial pressures of H2S higher than 0.3 kPa (0.05 psi). This work aims to mitigate internal corrosion in steel pipelines transporting natural gas containing H2S using cold spray coatings. Two types of the cold spray binary metallic coatings (zinc chromium [ZnCr]. zinc niobium [ZnNb]) were studied using electrochemical techniques: potentiodynamic polarization, linear polarization resistance, and electrochemical impedance spectroscopy. The corrosion resistance of cold spray coatings (ZnCr, ZnNb) was evaluated in an environment containing 4 bar CO2 pressure, simulating the partial pressures found in gas transmission lines over a solution of 3.5 wt% NaCl heated to 40°C. A concentration of 0.003 M Na2S2O3·5H2O, corresponding to H2S partial pressures around 0.079 bar (1.146 psi), was used to simulate sour conditions. Postcorrosion surface characterization was performed using a scanning electron microscope (SEM) equipped with an energy-dispersive x-ray spectroscope (EDS) and x-ray diffraction analysis. The data showed that the presence of 0.003 M Na2S2O3·5H2O shifted the corrosion potential to more anodic values and decreased the corrosion current density. Both coatings showed similar behavior after 1 h of exposure in the CO2/H2S environment, indicating that similar electrochemical reactions were occurring on ZnNb and ZnCr. SEM images and EDS surface analyses for specimens showed a significant change in the surface chemical composition of carbon steel coated with ZnNb and ZnCr after 24 h of immersion. In the presence of thiosulfate (under sour conditions), the formation of corrosion product layers (ZnCO3 and ZnS) on top of ZnNb and ZnCr coatings increased their corrosion resistance, which helped to reduce their corrosion by a factor of 2. Under a sweet environment, the corrosion rates for steel coated with cold spray coatings after 14 d of exposure are lower than that for galvanized steel by a factor of 5 due to the ZnCO3 layer formed on top of the coatings. The ZnCO3 layer formed on the steel surface acts as a physical barrier against corrosion by blocking the diffusion of corrosive species to the surface. No localized attack was observed. ZnCr Cold spray coating with defect showed promising corrosion protection against CO2 corrosion (sweet corrosion) after 14 d of exposure to a CO2 environment. The scratch on the coating simulated damage created in service, and it was deep enough to expose the substrate material (steel). The formation of zinc oxide (ZnO) and zinc carbonate (ZnCO3) on the scratch confirmed the cathodic protection of the steel by ZnCr and ZnNb coatings.

Effect of the incorporating of refractory NbC precipitates in intermetallic iron-aluminide coatings on corrosion and high-temperature oxidation behavior

This study aims to investigate the effects of growing niobium carbide (NbC) particles into intermetallic iron-aluminide (FeAl) coatings on ductile cast iron (SGI) by thermo-reactive diffusion technique (TRD). The study compares the corrosion and oxidation behavior of the FeAl-NbC coatings with SGI, FeAl, and NbC coatings. Corrosion tests were conducted through polarization tests in a 3.5 wt% NaCl solution, while oxidation tests were performed at 900 °C for 4, 16, and 64 h. Before and after corrosion and oxidation tests, the coatings were examined using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The findings show that FeAl coatings with NbC particles had lower graphite nodules, porosity, and surface roughness values compared to FeAl coatings. FeAl-NbC composite coatings provided better corrosion and oxidation resistance compared to untreated SGI, FeAl, and NbC coatings. The results of the comparative analysis of FeAl-NbC, FeAl, NbC, and untreated SGI specimens indicate that corrosion resistance in a 3.5 wt% NaCl solution and oxidation resistance at 900 °C followed the order FeAl-NbC > FeAl > NbC > SGI.

Service Life Prediction of Inhibitors and Concrete Surface Coatings in Concrete-Embedded Reinforcing Steel Corrosion Caused by Chloride

Service Life Prediction of Inhibitors and Concrete Surface Coatings in Concrete-Embedded Reinforcing Steel Corrosion Caused by Chloride

Effect of Al content on in-situ formation of Al2O3 protective layer on Ni-Al coatings in high-temperature chloride molten salt

The microstructure, strength, toughness, and resistance to chloride molten salt corrosion of Ni-Al coatings with varying Al content were investigated. Increasing the Al content from 9.9 to 61.1 at.% resulted in a decrease in adhesion strength and toughness, while an increase in corrosion rate. Contrary to previous reports, it is noteworthy that Ni-Al coatings with the lowest Al content exhibited superior resistance corrosion due to the formation of an oxidation layer which effectively blocked corrosion. This protective layer was primarily in-situ formed through the reaction between crystalline water present in the molten salt and an appropriate amount of Al. The balance between Al and O content is precisely regulated, resulting in the in-situ formation of Al2O3 protective.

Corrosion Behavior of Zn-Al-Mg-Si Coatings in Sulfur Dioxide-Containing Environment

Zn-Al-Mg-Si coatings are an excellent alternative to conventional hot-dip galvanizing coatings. Their high corrosion resistance in corrosive environments containing chlorides and CO2 is well recognized. But sulfur dioxide is also an important stimulator of corrosion in the atmospheric environment. This article presents the results of microstructure (SEM/EDS/XRD) and corrosion behavior tests of Zn-Al-Mg-Si coatings obtained by a double hot-dip method on HSLA steel. The corrosion resistance of the coatings was determined in the sulfur dioxide test with general condensation of moisture (EN ISO 6988). In the corrosion test, Zn-Al-Mg-Si coatings showed twofold smaller weight loss compared to conventional hot-dip zinc coatings. It was found that the corrosion behavior of coatings was influenced by the structural components revealed in the outer layer: Al-rich dendritic and interdendritic areas with Zn/MgZn2 eutectic, MgZn2 intermetallic and Si precipitates and their electrochemical nature. The increase in corrosion resistance was caused by the formation of beneficial corrosion products: layered double hydroxides (LDHs) based on divalent Mg2+ and Zn2+ cations, trivalent Al3+ cations and SO42− anions, and zinc hydroxysulfate—Zn4SO4(OH)6∙5H2O. The presence of Si precipitates could cause pitting corrosion of coatings.