Corrosion Resistance Of Coatings Research Articles

Effect of B on hot corrosion behavior of silicide coatings under different corrosive environments at 900 °C

Silicide coatings and B-modified silicide coatings were prepared on Nb-Si based alloys using halide activated pack cementation. The hot corrosion behavior of the coatings exposed to Na2SO4 and Na2SO4 + NaCl mixture salts at 900 °C was investigated. The results show that B-modified silicide coatings possess better hot corrosion resistance than the silicide coatings. The hot corrosion products of silicide coatings show a regional microstructure, including uplift regions of AlNaSiO4 imbedded with Al2O3 phases, and depressed silica regions with NaNbO3 and TiO2 particles. The addition of B to the silicide coatings promotes the formation of the uniform and dense boroaluminosilicate scale with better fluidity during hot corrosion, which impedes the self-sustaining cyclic chlorination/sulfidation reactions, and thus, improves the hot corrosion resistance of the silicide coatings.

Effect of Ti3SiC2 concentration on corrosion resistance and ICR in bipolar plates composite ceramic coatings

Ti3SiC2, a MAX-phase ceramic, amalgamates metallic and ceramic traits, delivering exceptional electrical conductivity and corrosion resistance. In this research, Ti3SiC2 composite coatings were applied to 316 L stainless steel via low-power atmospheric plasma spraying (APS), aiming to bolster the electrical and corrosion resistance attributes of bipolar plates (BPPs). A power input of 15 kW notably enhanced coating density, yielding a Ti3SiC2 concentration of 19.2 wt% in the coating. Extremes in the spraying power led to either diminished deposition efficiency or a reduction of Ti3SiC2 mass fraction below 5 wt%. Tafel curves demonstrated that specimens with elevated Ti3SiC2 mass fractions exhibited robust corrosion resistance, characterized by a self-corrosion potential of −162.5 mV and a self-corrosion current density of 1.7217 × 10−6 A·cm−2. Moreover, the interfacial contact resistance (ICR) between the coating and the gas diffusion layer was remarkably low (down to 5.49 mΩ·cm−2), indicating enhanced surface electron transfer with increasing Ti3SiC2 mass fractions.

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 0.75wt% 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 0.01Hz 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.

Effect of electrolyte pH value on microstructure and corrosion resistance of black MAO coating on 6063 aluminum alloy

Black micro-arc oxidation (MAO) coatings were obtained on the surface of 6063 aluminum alloy by using the MAO technique in silicate electrolyte with colorant NH4VO3. The work aimed to study the effect of adjusting the electrolyte pH (pH10, pH11, pH12, and pH13) on the microstructure, mechanical properties, and corrosion resistance of black MAO coatings on 6063 aluminum alloy. The experimental results showed that the electrolyte pH had an important effect on the macroscopic morphology of the MAO coatings. As the electrolyte pH value increased, the process voltage of the sample decreased, the duration of the anodic oxidation stage and the spark discharge stage were shortened, while the duration of the micro arc oxidation stage was prolonged. Reasonable adjustment of the electrolyte pH could reduce the poriness and defects of the coatings, decrease the surface roughness of the coatings, and improve the quality and wear resistance of the coatings. The corrosion resistance of the black MAO coating obtained in the electrolyte with pH12 was superior and the corrosion current density was only 3.207×10−7 A/cm2. The immersion corrosion test further demonstrated the same results of corrosion resistance.

Electroactive additives into polyurethanes for high corrosion resistance coatings for mild steel

Electroactive additives into polyurethanes for high corrosion resistance coatings for mild steel

An effective utilization of raw fly ash obtained from thermal power plants using thermal spray technique to improve corrosion resistance for marine applications

Marine-grade steel structures in offshore environments often corrode due to the aggressive environmental conditions. Many ceramic materials can cater to this demand. However, as per economic and ecological concerns, fly ash (FA), an industrial waste, can be another strong contender to control corrosion. Therefore, the present study developed composite coatings of fly ash with additives ((50-48) wt.% Al2O3; 0-2 wt.% carbon nanotube (CNT)) onto marine-grade steel using a plasma spray technique to improve its corrosion resistance. The microstructure of 1 wt.% CNT-reinforced alumina-FA (1CAF) coating was denser than 2 wt.% CNT-reinforced alumina-FA (2CAF) coating due to the uniform dispersion of CNT and, thereby, uniform remelting of coating at localized sites. Consequently, the microhardness and adhesion strength of the 1CAF coating were improved by ∼14.66 % and ∼15.96 %, respectively. Further, Rietveld’s analysis of coatings showed that quartz, being the primary phase for corrosion control, was 19.23 ± 0.87%, 16.33 ± 1.04% and 14.60 ± 1.87% for alumina-FA (AF), 1CAF, and 2CAF, respectively. The electrochemical impedance spectroscopy and the salt spray corrosion tests showed that 1CAF coating corrosion resistance was improved by ∼11.2 % compared to AF coating, even with a lower quartz phase (∼15.08 %) due to the densification of coating. This densification was due to the remelting by CNT to seal pores in the coating. Furthermore, for the same reason, an increase in coating resistance and charge transfer resistance of 1CAF coating by ∼80.9 % and ∼19.93 %, respectively, were seen in the equivalent circuit analysis, showing great promise in controlling interfacial corrosion. Further post-treatments like plasma or laser treatments can seal the coatings further to improve corrosion resistance. Therefore, such coatings are expected to withstand harsh, corrosive environments and are well-suited for marine applications.

An effective utilization of raw fly ash obtained from thermal power plants using thermal spray technique to improve corrosion resistance for marine applications

Marine-grade steel structures in offshore environments often corrode due to the aggressive environmental conditions. Many ceramic materials can cater to this demand. However, as per economic and ecological concerns, fly ash (FA), an industrial waste, can be another strong contender to control corrosion. Therefore, the present study developed composite coatings of fly ash with additives ((50-48) wt.% Al2O3; 0–2 wt% carbon nanotube (CNT)) onto marine-grade steel using a plasma spray technique to improve its corrosion resistance. The microstructure of 1 wt% CNT-reinforced alumina-FA (1CAF) coating was denser than 2 wt% CNT-reinforced alumina-FA (2CAF) coating due to the uniform dispersion of CNT and, thereby, uniform remelting of coating at localized sites. Consequently, the microhardness and adhesion strength of the 1CAF coating were improved by ∼14.66 % and ∼15.96 %, respectively. Further, Rietveld's analysis of coatings showed that quartz, being the primary phase for corrosion control, was 19.23 ± 0.87 %, 16.33 ± 1.04 % and 14.60 ± 1.87 % for alumina-FA (AF), 1CAF, and 2CAF, respectively. The electrochemical impedance spectroscopy and the salt spray corrosion tests showed that 1CAF coating corrosion resistance was improved by ∼11.2 % compared to AF coating, even with a lower quartz phase (∼15.08 %) due to the densification of coating. This densification was due to the remelting by CNT to seal pores in the coating. Furthermore, for the same reason, an increase in coating resistance and charge transfer resistance of 1CAF coating by ∼80.9 % and ∼19.93 %, respectively, were seen in the equivalent circuit analysis, showing great promise in controlling interfacial corrosion. Further post-treatments like plasma or laser treatments can seal the coatings further to improve corrosion resistance. Therefore, such coatings are expected to withstand harsh, corrosive environments and are well-suited for marine applications.

+Improving the corrosion protection properties of epoxy resin coating by using HKUST-1-BTA@e-Mica two-dimensional nanocomposites

In order to enhance the performance of epoxy coatings to cope with more severe working environments, we develop a convenient energy-saving and fast method to develop an eco-friendly pH-responsive smart coating with long-term corrosion protection. In this paper, HKUST-1 crystals were rapidly synthesised on mica nanosheets (e-Mica) using hydroxyl complex salt (HDS) as an intermediate at room temperature and loaded with the corrosion inhibitor BTA to obtain the composite material HBeM. The use of e-Mica in coatings offers numerous benefits, including extended resistance to corrosive media and the ability to adjust mechanical properties. It is important to note, however, that e-Mica is less compatible with epoxy resin. HKUST-1 can not only be used as a pH-responsive nanocontainer to load a large amount of corrosion inhibitor, but also to regulate the compatibility between mica nanosheets and epoxy resin with a large number of functional groups on HKUST-1. The results of electrochemical impedance spectroscopy showed that HKUST-1-BTA@e-Mica (HBeM) composite enables the coating to provide long-term corrosion protection. The low frequency impedance of the HBeM/EP composite coating, |Z|f=0.01 Hz, was improved by almost three orders of magnitude and remained higher than that of the pure epoxy coating after 30 days of immersion, and the addition of fillers enhances the mechanical properties of the coating. In conclusion, this paper provides a simple, energy-efficient and rapid method for the preparation of smart corrosion-resistant coatings, which has great potential for industrial use.

The Improvement in Corrosion Resistance of Electroless Ni-P Coating on Micro-arc Oxidized AZ31 Alloy Prepared with Sodium Dodecyl Sulfate Additive and Post-supercritical CO2 Mixed Electrolyte

The Improvement in Corrosion Resistance of Electroless Ni-P Coating on Micro-arc Oxidized AZ31 Alloy Prepared with Sodium Dodecyl Sulfate Additive and Post-supercritical CO2 Mixed Electrolyte

Enhanced mechanical properties and corrosion resistance of electro-deposited NiCoP composite coatings with ZrB2 particle addition

This work was initiated with the purpose of expanding the utilization of nickel-based composite coatings, especially in wear and corrosion-related industrial applications. NiCoP coatings have long attracted scientific and engineering interest due to their enhanced mechanical properties reinforced by incorporation with a reinforcement phase. In the present study, NiCoP composite coatings reinforced with ZrB2 ceramic particles were synthesized by direct current deposition using a modified Watt’s type bath. The microstructures of composite coatings were studied by x-ray diffraction analysis, energy dispersive x-ray spectroscopy, and scanning electron microscopy, respectively. The hardness and tribological properties of the composite coatings were evaluated and compared. The corrosion behaviors of the deposits were investigated using electrochemical spectroscopy and potentiodynamic polarization techniques in simulated seawater. The effect of ZrB2 content on the microstructures and mechanical properties of the composite coatings was explored and discussed. The present study indicates that there is a progressive enhancement in the hardness, corrosion resistance, and wear resistance of the composite coatings with the increase in ZrB2 loading. The NiCoP-12 g/l-ZrB2 coating possesses the highest microhardness and superior wear performance, while the NiCoP-6 g/l-ZrB2 coating exhibits the best anti-corrosion properties. The present study shows a cost-effective and feasible solution for the preparation of NiCoP protective coatings with enhanced properties, which holds great potential for industrial applications requiring wear and anti-corrosion protection.

Effect of Y2O3 on Microstructure and Corrosion Resistance of Ni45 Coating by Laser Cladding with Different Flow Rates of Carrier Gas

Effect of Y2O3 on Microstructure and Corrosion Resistance of Ni45 Coating by Laser Cladding with Different Flow Rates of Carrier Gas

Self-stabilized styrene-acrylic copolymer latex with heteroatom function for improved water and corrosion resistant coatings

This approach investigates the preparation of a set of styrene-acrylic copolymers incorporated with N-heteroatom in the form of N-vinyl pyrrolidone (NVP) as the functional co-monomer at different concentrations within the range of 17–33 mol%. In this case, self-stabilized copolymer latex was obtained without using any conventional surfactant in the system. The beneficial effect of NVP for the emulsion copolymerization of styrene and butyl acrylate was quantified by preparing and analyzing a control sample of the same copolymer latex that was stabilized by a conventional surfactant. The prepared self-stabilized copolymer latexes having particle sizes of 325–371 nm showed excellent colloidal stability with a zeta potential of >+44.5 mV. The air-dried films were found to be optically transparent and comparable to the control sample. The thermal, structural, microscopic, and water/alkali resistance properties of the films were characterized with respect to the NVP content in the copolymer. The coating characteristics of the copolymers on glass slides and mild steel panels were explored by analyzing the hydrophobicity (water contact angle up to 79°) and corrosion resistance (corrosion rate: 6.03 × 10−5 mm/year) that are significantly improved from the copolymer prepared by conventional emulsion polymerization. This study reveals the impact of N-heteroatom to obtain a self-stabilized polymer latex with improved properties and additional functionalities.

Bacterial and corrosion resistance of polytetrafluoroethylene-silver composite coatings by magnetron sputtering

Titanium alloy and stainless steel implants have been widely applied in orthopedics. However, harmful ions released from implant corrosion caused by human body fluids and bacterial infections may inhibit patients’ recovery. In this work, a polytetrafluoroethylene-silver composite coating was prepared by RF unbalanced magnetron sputtering to improve the bacterial and corrosion resistance of the SS316L. The removal rates of the composite coatings for Escherichia coli and Staphylococcus aureus reached 97.27% and 99.99%, respectively. The contact angle of 131.5° and fluorescence staining experiments show that the composite coating has an antiadhesive effect on bacteria and less cytotoxicity against osteoblasts. The corrosion voltage of the composite coating was much higher than that of the control SS316L substrate, and the corrosion current density was reduced to 1/3, implying the enhancement of the corrosion resistance of the SS316L substrate.

The Effect of Preheating Temperature on the Corrosion Resistance and Porosity Defects Development Behaviour of Ni60A Coating

The laser cladding of nickel-based fusion alloys makes them prone to cracks and defects that affect the overall performance of the coating. In this study, Ni60A coatings were prepared at different preheating temperatures (25 °C, 200 °C, 400 °C and 600 °C). The effect of the preheating temperature of the substrate on the corrosion resistance of the coating as well as on the development of defects were investigated by electrochemical tests and immersion experiments in a 65 wt% H2SO4 solution at 60 °C. The results indicate that preheating the substrate to 200 °C can completely eliminate cracks in the coating and reduce porosity. Preheating leads to a decrease in the corrosion resistance of the coating. The size of the porosity defects is related to the law of longitudinal development of the defects. Porosity defects with diameters smaller than 100 μm have a more pronounced tendency to expand vertically than those with diameters larger than 100 μm.

Investigating the CMAS corrosion resistance and thermal cycling failure behavior of porous thermal barrier coatings with different morphologies prepared by plasma spraying

This study investigates the influence of two-phase powder feeding spacing on the thermal cycling and CMAS corrosion resistance of the thermal barrier coatings (TBCs). Porous thermal barrier coatings with varying microstructures were prepared using the embedded micro agglomerated particle (EMAP) coating preparation method, which is based on conventional yttrium stabilized zirconia (YSZ) coatings. The method involved changing the powder feeding spacing. TBCs' failure mode and microstructure are investigated under complex service conditions. The corrosion resistance, thermal cycling life, hardness, and elastic modulus of TBCs are investigated by thermal cycling-CMAS experiments and isothermal corrosion tests. The EMAP coating has a good service life in the thermal cycling-CMAS tests, with a lower hardness, lower elasticit modulus and larger surface roughness than conventional coatings. This research aims to provide a strategy to optimize structure for TBCs with excellent comprehensive performance.

Effect of solution temperature on the microstructure and properties of ceramic coating on the surface of 2024 aluminum alloy

This study investigates the influence of the 2024 aluminum alloy was treated with solution before ceramic treatment on the microstructure and characteristics of ceramic coatings applied to 2024 aluminum alloy substrates. The microhardness, corrosion resistance, and microstructural properties of these ceramic coatings were assessed using a microhardness tester, an electrochemical workstation, and a scanning electron microscope. The findings indicate that pre-treatment involving solution treatment significantly enhances the hardness and corrosion resistance of 2024 aluminum alloy ceramic coatings. Notably, when the solution temperature was maintained at 460 °C, the most rapid decrease in current density was observed during the ceramization process, resulting in the attainment of the lowest final stable current density. This particular condition yielded ceramic coatings with optimal hardness and corrosion resistance, with hardness exhibiting a remarkable increase of 48.9 HV, self-corrosion potential rising by 0.207 V, and polarization resistance surging by 5310.7 Ω. Moreover, the surface of the ceramic coating displayed remarkable smoothness and was devoid of discernible defects such as cracks or looseness. In light of these findings, it can be concluded that the optimum solution temperature for achieving these desirable properties is 460 °C. This conclusion is derived from a comprehensive analysis encompassing both the morphology and corrosion resistance of ceramic coatings.

Corrosion Resistance of Magnesium Ammonium Phosphate Cement-Based Coatings Modified by Calcium Sulfoaluminate Cement on Carbon Steel in a Saline Medium

Corrosion Resistance of Magnesium Ammonium Phosphate Cement-Based Coatings Modified by Calcium Sulfoaluminate Cement on Carbon Steel in a Saline Medium

Microstructure Evolution and Molten Salt Corrosion Resistance Dependent on Pre-Oxidation Treatment of NiAl Coatings

The chloride-infused molten salt shows the most potential as the medium for the upcoming generation of concentrated solar power system. However, the molten salt put for ward higher corrosion resistance demand on the critical components of concentrated solar power system. The application of NiAl coating proves to be a highly efficient method for preventing corrosion. In this paper, the microstructure, adhesion, and corrosion resistance of NiAl coatings on 310S stainless steel with/without pre-oxidation treatment were studied. The coating predominantly consisted of β-NiAl phase nanocrystals with an Al content of 41.0 at.%. Continuous α-Al2O3 oxide film was formed and no obvious cracks were observed after pre-oxidation. The adhesion strength of NiAl coating was increased by about 70% to 40.0 N through pre-oxidation. Importantly, the corrosion results of NiAl coatings by pre-oxidation treatment in the mixed salt of NaCl/MgCl2/KCl at 1073.15 K for 10 h showed no obvious diffusion of molten salt elements into the coatings. Compared to 310S stainless steel, the pre-oxidized coating sample exhibited a significant reduction of 50.2% in corrosion mass loss. The pre-oxidation of the NiAl coating creates an Al2O3 oxidation layer that effectively blocks corrosion, offering a new method for protecting stainless steels in concentrated solar power system plants.

Corrosion Resistance of Zinc-Doped Hydroxyapatite Coating on Titanium Substrate using Plasma Electrolytic Oxidation for Biomedical Applications

Corrosion Resistance of Zinc-Doped Hydroxyapatite Coating on Titanium Substrate using Plasma Electrolytic Oxidation for Biomedical Applications

Influence of Additives on the Macroscopic Color and Corrosion Resistance of 6061 Aluminum Alloy Micro-Arc Oxidation Coatings.

In this study, we successfully employed the plasma electrolytic oxidation (PEO) technique to create a uniform white ceramic layer on the surface of the 6061 aluminum alloy using K2ZrF6 and Na2WO4 as colorants. A scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS) and X-ray diffraction (XRD) were used to characterize the coatings, and we used an electrochemical workstation to test their corrosion protection properties. The corrosion resistance of the coatings was analyzed using potentiodynamic polarization curves. The results showed that K2ZrF6 addition whitened the coating with ZrO2 as the main phase composition, inhibiting Al substrate depletion and enhancing coating corrosion resistance. A small amount of Na2WO4 decreased the coating's L* value, successfully constructing ceramic coatings with L* (coating brightness) values ranging from 70 to 86, offering broad application prospects for decorative coatings.