Corrosion Resistance Of Coatings Research Articles

Preparation of AlCoCrFeNi/W-TiC HEA composite coating by laser cladding

In this paper, AlCoCrFeNiW2-x(TiC)x high-entropy alloy coatings (HEA) (x: mass fraction, x = 0, 0.5, 1.0, 1.5, and 2) were prepared on 316 stainless steel (316 L SS) substrate by laser cladding technique. The microstructure, phase, microhardness, wear resistance and corrosion resistance of the HEA composite coatings were discussed by adding different mass fractions of W and TiC particles. The results show that the coatings are metallurgically bonded under the experimental parameters, and the grain size of the coating decreases from the interface to the surface, which is in accordance with the constitutional undercooling criterion. Meanwhile, the contents of W and TiC can adjust the mechanical properties of the coatings. The microhardness of the coatings increases and then decreases with the variation of x value, which can be explained by the large number of TiC particles leading to severe lattice distortions and high internal stresses, which results in the fluctuation of microhardness in the cross-section. The coating exhibits the best microhardness, with an average microhardness of 452 HV when x = 0.5. The wear resistance of the coating is better with an average coefficient of friction of 0.4474 when x = 0.5. However, due to the presence of phase-boundary defects in the composite coatings, which contain cationic and anionic vacancies, When the passivation film is damaged by Cl-, the electrolyte will penetrate along the phase boundary defects and generate corrosive microcells.

Enhancement of ammonia corrosion resistance of coatings through improving dispersion and binding site of graphene oxide in silane coatings

Copper metal is essential to our production process, but it is highly corrosive in an ammonia environment and must be highly valued. Anti-corrosion coating is a simple and cost-effective method of preventing metal corrosion. In this study, a composite silane coating was prepared on copper using an impregnation method with mercaptopropyltriethoxysilane (TPTES) as the silane substrate and graphene oxide (GO) modified with isophorone diisocyanate (IPDI) or isocyanatopropyltriethoxysilane (IPTS) as filler to protect the copper from ammonia corrosion. The coating samples were hanging tested against ammonia corrosion by setting up two corrosive environments: ammonia gas and ammonia water. After 20 days of corrosion, the surfaces of the TPTES/IPDI-GO and TPTES/IPTS-GO coatings remained unchanged under both ammonia environments and the corrosion rate was consistently low at 2–3 μm/y. Additionally, the coating exhibited high protective qualities according to the electrochemical impedance spectroscopy (EIS) test in a 3.5% NaCl solution, which is attributed to the good dispersion that improves the densification and regularity of the coating. Meanwhile, IPTS-GO has a greater binding force with the coating matrix due to the increased number of reactive sites, resulting in further improved corrosion protection. This study provides an idea for research on ammonia-resistant coatings.

Interaction mechanisms and high-temperature erosion-oxidation performance of Cr3C2-NiCrCoMo/nano-TiC coatings

To improve the erosion resistance of typical Cr3C2-NiCr coatings at high temperature, a novel Cr3C2-NiCrCoMo/nano-TiC (NCT) coating was developed and deposited by the high-velocity oxygen fuel spray (HVOF), which involved a cooperative modification of the multi-alloy binding phase and ceramic phase. This study delves into the influence of nano-TiC on the coating’s resistance to erosion under varying impact angles, particularly at 700 °C and 800 °C. Additionally, it explores the interaction between oxidation and erosion processes within the coating. The results indicated that the NCT1 coating with the addition of 3 wt% TiC features lower erosion rates of 1.97, 2.56, 3.14 mg/g under the impact angles of 30°, 60° and 90° at 700 °C, and 2.16, 2.87, 3.49 mg/g at 800 °C compared with original NCC coating. By comparison, the NCT2 coating with 6 wt% nano-TiC shows a deterioration in erosion resistance. The results show that at high temperatures, the erosion resistance of the coating changes from the micro-cutting at lower angles, to the brittle fracture and spalling at higher angles. The appropriate addition of nano-TiC supports and stabilizes the metal binding phase of the NCT1 coating. However, excessive nano-TiC in NCT2 coating contributes to the separation of coating phases during the erosion. The oxidation of the nano-TiC promotes the diffusion of Cr3+ ions, thus accelerating the coating oxidation and deteriorating the high-temperature erosion resistance eventually. The study is anticipated to enhance the longevity and the high-temperature erosion resistance of Cr3C2 cermet coatings, offering significant advancements in practical applications.

Plasma-chemical synthesis of carbide-based vacuum-plasma functional coatings and study of tribological characteristics of friction pairs

The work is devoted to the search for new materials with high functional characteristics using the Avinit vacuum-plasma technologies developed by us, based on the complex use of coating methods (plasma-chemical CVD, vacuum-plasma PVD (vacuum-arc, magnetron), processes of ion saturation and ion surface treatment), stimulated by non-equilibrium low-temperature plasma.Processes of controlled plasma-chemical synthesis of the formation of multicomponent coatings in "metal-carbon" systems – Avinit coating (TiC, MoC) using vacuum-arc sources of ionized atomic fluxes of titanium and molybdenum in an argon-benzene plasma environment were developed and their characteristics were studied depending on their conditions formation.Metallographic studies confirm the possibility of low-temperature application of high-quality wear-resistant high-hard "metal-carbon" coatings with a hardness of 18,000-30,000 MPa, while ensuring good adhesion to the substrate materials (steel DIN 1.2379) without reducing strength and without deteriorating the cleanliness class of the original surface.The conducted tribological tests using the "cube-roller" scheme reveal high tribological characteristics of steel DIN 1.2379 tribopairs with developed coatings and testify to the promisingness of the developed multi-component multilayer coatings Avinit (Ti-C, MoS) for increasing wear resistance and reducing the coefficient of sliding friction in friction nodes.The developed plasma-chemical vacuum-plasma coatings are applied to mock-up samples of the working compressor blades of the GTE of aircraft engines. Proven modes allow to get high-quality, uniform coatings with high adhesion.This gives reason to consider the developed process as an alternative for expanding the range of new Avinit vacuum-plasma erosion-resistant coatings and developing structures of anti-friction wear-resistant coatings to increase the performance of friction pairs in "coating-steel" and "coating-coating" systems.

Effects and mechanism of Zn on the structure and corrosion resistance of microarc oxidation coatings on aluminum alloy

A composite Zn coating is prepared on 2024 aluminum alloy by microarc oxidation (MAO) and the corrosion resistance is investigated. During MAO, the addition of an appropriate concentration of Zn2+ regulates the size and intensity of surface sparks on the sample giving rise to a uniform distribution of MAO current and less large discharge channels. The crystal structure of Al2O3 is compressed and the density of the coating increases. The coating has the Zn3Al94O144 phase and electrochemical tests reveal a corrosion current density (icorr) that is 3 orders of magnitude smaller than that of the coating without Zn doping. Density-functional theory calculations show that Zn inhibits the adsorption of Cl- and consequently reduces the damage to the passivation layer.

Improvement in corrosion resistance of AZ91D Mg alloy in simulated body fluid by cerium-based/stearic acid composite coatings

Magnesium alloys have attracted attention due to their biocompatibility and biodegradability. In this work, composite coatings are developed to potentially improve the corrosion resistance of AZ91D Mg alloy in simulated physiological fluid. Cerium-based/stearic acid coatings were prepared by electrodeposition combined with a simple immersion method. The effect of stearic acid bath concentration on the contact angle and corrosion resistance of the composite coatings was evaluated. The results showed that the stearic acid treatment increased the hydrophobicity of the surfaces of the cerium-based simple coatings. The use of an appropriate stearic acid concentration is a key for the fabrication of hydrophobic surfaces. The duplex coatings were demonstrated to protect the substrate from corrosion in Ringer solution.

Air-based sputtering deposition of TiN(O)/a-TiNxOy multilayer films for enhanced mechanical properties and corrosion resistance

Extensive research has explored multilayer films for their distinctive mechanical and functional properties. This study employs an air-based sputtering technique, using air as a reactive gas under low vacuum conditions, to produce TiN(O)/a-TiNxOy multilayer films. By alternately adjusting the air/Ar flow ratios, the multilayer films with various modulation periods were created. The crystalline TiN(O)/amorphous TiNxOy multilayered structure was confirmed via cross-sectional microscopy and electron energy loss spectroscopy images and mappings. Hardness (H) and elastic modulus (E) initially increased, peaked, and then decreased with the modulation period, reaching a maximum hardness of 31.2 GPa and an elastic modulus of 343 GPa. The enhancements may be attributed to internal compressive stress, interface strain effects, and the inhibition of dislocation propagation throughout the films. Higher H/E ratios (0.09–0.11) and H3/E2 ratios (0.23–0.28 GPa) suggest enhanced resistance to elastic and plastic deformation, surpassing those of single-layered TiN(O). This enhancement is primarily attributed to the hard/soft multilayer design. Potentiodynamic polarization tests revealed improved corrosion resistance with decreasing modulation period, reaching optimal values Ecorr at −0.089 V and Icorr at 0.272 μA/cm2. This improvement is mainly ascribed to the multilayer design, which inhibits direct corrosion through grain boundaries. This air-based sputtering technique offers a facile approach for producing complex multilayer films, promising enhanced mechanical properties and corrosion resistance of coatings for various applications.

Development and electrochemical investigations of enhanced corrosion-resistant Polyvinylcarbazole-TiO2 hybrid nanocomposite coatings on 316L SS for marine applications

The present study focuses on evaluating the corrosion resistance of 316L stainless steel substrates with Polyvinylcarbazole (PVK)/TiO2 hybrid nanocomposite coatings (HNC). Using the chronoamperometry approach, the HNC were electrochemically synthesized on 316L stainless steel substrates, incorporating various weight (%) 1 %, 2 %, 3 % of TiO2 nanoparticles into the PVK matrix. The findings of the surface morphology investigation verified that the 316L SS had a dense and smooth PVK/TiO2 coating. A low surface roughness and high contact value of the PVK/TiO2 coatings are also responsible for the decrease in corrosion rate of the 316L SS. The corrosion protection efficiency of the PVK/TiO2 HNC were investigated through open circuit potential (OCP) measurement, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analysis in 3.5 wt% NaCl solution. The corrosion rate obtained from the polarization studies of the HNC coatings as follows PVKT-2 < PVKT-3 < PVKT-1 < PVK < 316L SS. Results revealed that an optimal loading of 2 wt% TiO2 nanoparticles significantly enhanced the corrosion resistance of the coating. The enhanced electrochemical impedance response for PVK/TiO2 coatings was verified by EIS experiments. The study demonstrates that the incorporation of TiO2 nanoparticles into the PVK matrix effectively creates a barrier layer at the coating-metal interface, inhibiting the entry of aggressive ions. Microhardness studies revealed the increase in hardness value of the PVK and PVK/TiO2 coatings indicated the protective nature of the coating and provided high mechanical strength to 316L SS. The tape adhesion tests carried out on the coated specimens also indicated a good adhesion of the PVK/TiO2 on the 316L SS surface.

Fabrication Aspects and Performance Characterization of α-Al2O3/AlPO4 Based Sandwich Configuration Flow Channel Inserts and Coatings for High Temperature Liquid Metal Applications

Abstract Liquid metals (LMs) exhibit several key characteristics justifying their utilization as coolants and breeders for nuclear fusion reactors and advanced fission reactors. In fusion reactors, the LMs confront an exorbitantly high flow retarding force, due to the magneto-hydro-dynamics (MHD) effect, imposing significant demands on the pumping power and designs of ancillary coolant systems. Corrosion of structural materials leading to activated corrosion products and coolant chemistry control are some of the vital issues common to both fusion and fission reactors employing liquid lead (Pb) and its alloys. To address these concerns, different technological solutions such as flow channel inserts (FCIs) and high temperature compatible corrosion resistant coatings are being investigated to provide a chemical and/or electrical isolation between the LM and structural material for advanced reactors. In this study, three different prototype geometries (circular, square, and 90 deg bend) of steel-insulator-steel sandwich FCIs are fabricated for fusion reactor applications and an extensive characterization of the electrical insulation is performed over an operating temperature range of 100 °C–600 °C. Welding trials and pneumatic pressure tests up to 10 kg/cm2 (g) are performed on the assemblies to validate the electrical and mechanical integrity over typical fusion reactor operational regime. This paper presents detailed fabrication aspects along with quantitative estimations of insulation filling density, electrical insulation performance and, for the first time, a detailed systematic study of insulation degradation resulting from the combined effects of tungsten inert gas (TIG) welding, exposure to pressure and machining operations on these FCIs. The paper also provides critical details derived from the metallurgical examinations and visual observations from the destructive tests executed on the prototypes. Further, from an implementation perspective toward Lead-cooled Fast Reactors (LFRs), a preliminary feasibility assessment of the α-Al2O3/AlPO4 coating is performed through thin film deposition trials on planar and non-planar substrates followed by mechanical characterizations, such as coating thickness, surface roughness, adhesion strength and microhardness. Metallurgical analyses are presented and discussed to assess Pb ingress after 700 h of continuous exposure to molten Pb alloy at 300 °C–400 °C.

Effect of ultrasound assistance on the mechanical performance and corrosion resistance of Zn-Ni coatings produced by cathode plasma electrolysis deposition

Zn-Ni coatings were fabricated via ultrasonic-assisted cathodic plasma electrolysis deposition (US-CPED) technology. The results demonstrate that ultrasonic assistance can significantly affect the deposition and growth process of Zn-Ni coatings, which is attributed to ultrasonic vibration reducing the diameter of bubbles and inducing a more uniform distribution of the vapor gaseous envelope (VGE) on the surface of the substrate. The Zn-Ni coatings with more homogeneous microstructure were formed due to the more uniform plasma discharge process on the surface of the substrate based on the VGE uniform distribution. Compared to the Zn-Ni coatings without ultrasonic assistance, the thickness and roughness of Zn-Ni coatings with ultrasonic assistance increased by >80 % and decreased by over 40 %, respectively. Better Zn-Ni coating quality brings higher corrosion resistance. In addition, ultrasound can accelerate the iteration of bubbles in VGE to enhance the work-hardening effect, improving the mechanical properties of the Zn-Ni coatings. This work introduces a novel insight into the controllability of the CPED process and paves the way for exploring other methods to stabilize the CPED process.

Amino-Modified Graphene Oxide from Kish Graphite for Enhancing Corrosion Resistance of Waterborne Epoxy Coatings.

Waterborne epoxy (WEP) coatings with enhanced corrosion resistance were prepared using graphene oxide (GO) that was obtained from kish graphite, and amino-functionalized graphene oxide (AGO) was modified by 2-aminomalonamide. The structural characteristics of the GO and AGO were analyzed using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). And the anti-corrosive performance of waterborne epoxy-cased composite coatings with different addition amounts of AGO was investigated using electrochemical measurements, pull-off adhesion tests, and salt spray tests. The results indicate that AGO15/WEP with 0.15 wt.% of AGO has the best anti-corrosive performance, and the lowest frequency impedance modulus increased from 1.03 × 108 to 1.63 × 1010 ohm·cm-2 compared to that of WEP. Furthermore, AGO15/WEP also demonstrates the minimal corrosion products or bubbles in the salt spray test for 200 h, affirming its exceptional long-term corrosion protection capability.

Anti-corrosion resistance of coatings based on powder epoxy paints containing modifiers

The corrosion resistance of coatings (thickness 70 µm) based on epoxy powder paints modified with aliphatic amine or a mixture of anticorrosive pigments to the action of sodium chloride solution and salt spray has been studied. It is showed that with the increase of molecuar weight of initial epoxy oligomer and also at the incorporation of chemisorbing alifatic amine, containing polar groups, to the decrease in the permeability of the sodium chloride solution into the coating material is observed. It has been established that the observed changes in the properties of the coatings are due to the formation of a spatial structure of the polymer with different cross-link frequencies. It is shown that the introduction of a mixture of anti-corrosion pigments into the composition of paints provides a significant increase in the protective properties of coatings and a high preservation of the physical and mechanical properties of coatings in comparison with the base compositions. For 9000 hours of testing in a sodium chloride solution, the strength characteristics of the coatings decrease by about 10–12 % from the original ones. Based on the results of tests of coatings to the action of salt spray, the possibility of using the developed epoxy powder paints for operation in environments of a high atmospheric-corrosive category – C 5–1, including the application of coatings directly on a metal surface (Direct to metal) without multi-stage preparation of the metal surface for painting, is shown.

Effect of TiC nanoparticles on microstructure and corrosion resistance of laser cladding Al-CNTs composite coatings on AZ31 alloy

ABSTRACT Al-CNTs composite coatings were successfully prepared on AZ31 alloy using laser cladding (LC). The effect of TiC nanoparticles on microstructure and corrosion resistance of the LC Al-CNTs and Al-TiC-CNTs composite coatings were investigated. The LC composite coatings were composed of α-Mg solid solution phase and β-Al12Mg17, Mg2Al3, Mg32(Al,Zn)49 and TiC compound phases. A sound metallurgical bonding interface was produced between the LC composite coatings and AZ31 alloy. The surface microhardness and corrosion resistance of the LC composite coatings, which were gradually decreased with increasing the content of carbon nanotubes (CNTs) and TiC nanoparticles, were significantly enhanced compared to those of the AZ31 alloy. The LC Al-CNTs (99 wt% Al + 1 wt% CNTs) composite coating exhibits excellent surface microhardness and corrosion resistance. The mean surface microhardness, self-corrosion potential and self-corrosion current were 266.4 HV, −1.233 V and 2.55 × 10−5 A, which were 426.2%, 78.9% and 16.5% of the AZ31 alloy, respectively.

Heterogeneous nucleation induced A. pernyi/B. mori silk fibroin coatings on AZ31 biometals with enhanced corrosion resistance, adhesion and biocompatibility

Silk fibroin coatings on biomedical magnesium alloys have garnered significant attention due to their enhanced corrosion resistance and biocompatibility. However, the utilization of wild A. pernyi silk fibroin, known for its RGD sequence that facilitates tissue regeneration, presents a challenge for corrosion-resistant coatings on magnesium alloys due to its weak adhesion and high dissolution rate. In this study, we employed hexafluoroisopropanol as a solvent to blend A. pernyi silk fibroin with B. mori silk fibroin. The resulting blended fibroin coating at a 3:7 mass ratio exhibited a heterogeneous nucleation effect, enhancing β-sheet content (32.3 %) and crystallinity (28.6 %). This improved β-sheet promoted the “labyrinth effect” with an Icorr of 2.15 × 10−6 A cm−2, resulting in significantly improved corrosion resistance, which is two orders of magnitude lower than that of pure magnesium alloy. Meanwhile, the increased content of exposed serine in zigzag β-sheet contributes to a higher adhesion strength. Cell cytotoxicity evaluation confirmed the enhanced cell adhesion and bioactivity. This work provides a facile approach for wild A. pernyi silk fibroin coatings on magnesium alloys with enhanced corrosion resistance, adhesion and biocompatibility.

Influences of flame remelting and WC-Co addition on microstructure, mechanical properties and corrosion behavior of NiCrBSi coatings manufactured via HVOF process

We investigated the microstructures, mechanical properties, and corrosion behavior of NiCrBSi coatings upon the addition of the WC-Co powder in various amounts (0, 5, 10, 15, and 20 wt%) using the high velocity oxy-fuel process on low-carbon steel. Additionally, flame remelting was performed at 1100 °C for 1 min following thermal spraying of the coatings. The microstructures of the coatings were examined using X-ray diffractometry and scanning electron microscopy, and the mechanical properties of the coatings were assessed via Vickers microhardness and ball-on-disk tests. The corrosion behavior of the coatings was evaluated using potentiodynamic polarization testing in a 20 vol.% sulfuric acid solution. The results demonstrated that an increase in the WC-Co amount enhanced the hardness and wear resistance of the coatings. For 10–20 wt% WC-Co addition, small cracks were observed in the as-sprayed coatings owing to the heat applied during thermal spraying and rapid cooling, respectively. The presence of porosity directly affects the corrosion behavior of the coatings. Flame remelting led to better cohesion and the distribution of the γ-Ni and WC phases, reducing microdefects, such as pores and cracks. The mechanical properties of the coatings improved as the WC-Co amount increased after flame remelting, resulting in the formation of intermetallic compounds (FeB, CoSi2, and Ni2Si) along with the WC phase. The flame-remelted NiCrBSi/ 10 wt% WC-Co coating demonstrated high hardness and low wear and corrosion rates (1072.26 HV, 4.8 × 10−6 mm3/m, and 0.560 mm/year, respectively). Therefore, WC-Co addition and the flame remelting process significantly enhanced the properties of NiCrBSi coatings. This study highlights the substantial contributions of WC-Co addition and the flame remelting process in enhancing the mechanical properties and corrosion resistance of NiCrBSi coatings. These findings offer valuable insights for optimizing the performance of commercially available coatings in various real-world applications in maintaining power plants and industrial components like high-pressure pump piston rods, acid-resistant pumps in oil refineries.

Corrosion behavior and incorporation mechanism of Y2O3-TiO2 composite coatings fabricated on TC4 titanium alloy by plasma electrolytic oxidation

The anti-corrosion of titanium alloys is a topic of concern in many fields. In our work, the Y2O3-TiO2 composite coatings were fabricated on the TC4 titanium alloy by plasma electrolytic oxidation (PEO). The reaction was conducted in an electrolyte system made up of Na2SiO3, KOH, and (NaPO3)6. The effects of additive Y(NO3)3 in the electrolyte on the microstructure, chemical component, phase structure, thickness, hydrophobicity, and corrosion resistance of the composite coatings were studied. The results show that the composite coatings prepared by PEO reaction exhibit preferable corrosion resistance. The addition of Y(NO3)3 is beneficial for thickening the coatings, reducing their porosity and pore size, and further improving their hydrophobicity and corrosion resistance. Furthermore, the incorporation mechanism of Y2O3 was discussed based on thermodynamics theory.

Effect of titanium interlayer configurations on residual stresses and performance of titanium/titanium nitride multilayer coatings

Multilayer coatings provide an effective measure to control and optimise of residual stresses, enhance coating adhesion, fracture toughness, wear and corrosion resistance of coating system. In this study, we designed and produced bi-layer and four-layer titanium/titanium nitride magnetron sputtered coating configurations by altering the position of the interlayer. The in-plane residual stresses in different coating configurations are measured by multiple peak grazing incidence X-ray diffraction techniques. Subsequently, the effect of different compressive residual stresses on adhesion, mechanical properties, wear and corrosion resistance of coatings are investigated. Results show that the position of interlayer in multilayer coating configuration has a great impact on relaxation of residual stresses. The residual stresses are relieved by 26% and 46% by lowering the position of titanium interlayer from 800 nm at the top to 1000 nm and 1200 nm, respectively. The nanoindentation hardness is decreased by 11% and 13%, respectively. The wear rate of multilayer coating having interlayer position at 800 and 1000 nm from the top is ≈ 23% lower compared to bilayer however it is increased by ≈ 50% when interlayer coatings position changed to 1200 nm from the top. The interposition of interlayer in multilayer coating configurations decreased the corrosion current density by ≈ 50%. All multilayer coatings including higher residual stresses show better adhesion to the substrate compared to bilayer coatings which shows severe delamination.

Effect of Al content on the microstructure, mechanical property and lead-bismuth eutectic corrosion resistance of refractory AlxTiNbZrMoV coatings produced by magnetron sputtering

In present study, refractory AlxTiNbZrMoV (x=0.2, 0.5, 0.9 and 1.2 in molar ratio) high-entropy alloy coatings were prepared by magnetron sputtering technology. The microstructure, mechanical property and lead-bismuth eutectic corrosion resistance of the AlxRHEA coatings were investigated. With the increase of Al content, the coatings maintained the amorphous structure, and no intermediate phase was generated. The hardness and elastic modulus of the AlxRHEA coatings were higher than that of Al-free coating. After the LBE corrosion, formation of surface Fe-oxide layer occurred in the four AlxRHEA coatings. The Al0.5RHEA and Al0.9RHEA coatings exhibited improved corrosion resistance. The results indicate that for HEA, the formation of protective alumina layer can be on the basis of Al enrichment on the coating surface to continue to improve the oxidation resistance.

Advancements in Multilayer Coatings on Aluminium Alloy-Based Bipolar Plates for PEMFC Application

Fuel cells represent a revolutionary and sustainable approach to energy conversion, offering a clean alternative to traditional combustion-based power generation. These electrochemical devices convert the chemical energy of a fuel, typically hydrogen, directly into electricity. The fundamental working principle involves the electrochemical reaction between hydrogen and oxygen, facilitated by a catalyst, to produce electricity, water, and heat as byproducts in Proton Exchange Membrane (PEMFC). This strategic use of aluminum (Al) alloy for Bipolar plates (Bp) aligns with the industry's commitment to advancing materials and design methodologies, ultimately promoting the optimization of fuel cell technology in terms of performance, durability, and economic feasibility. This comprehensive review investigates recent progress in the development of multilayer coatings tailored for Al alloy-Bp in PEMFCs. Al alloys are a preferred substrate material due to their cost-effectiveness, lightweight nature, and high thermal conductivity. However, challenges such as corrosion, electrical conductivity, and interfacial contact resistance have spurred extensive research into innovative coating solutions. The review critically examines various coating materials, deposition techniques, and performance evaluation methods aimed at addressing the challenges associated with al alloy Bp. Special emphasis is placed on corrosion-resistant coatings, conductive layers, and interfacial modifiers. The assessment encompasses both established technologies and cutting-edge approaches, including nanocomposite coatings, self-healing materials, and advanced characterization methods. By synthesizing and analyzing existing literature, this review provides a comprehensive overview for researchers, engineers, and policymakers involved in advancing PEMFC technology. The findings underscore the crucial role of multilayer coatings in augmenting the performance and longevity of al alloy-based Bp, offering valuable insights to guide further research and development in the pursuit of efficient and durable fuel cell systems. In comparing the aluminum grades Al-356, Al-5052, Al-6061, and Al-7075, it is observed that Al 5052 exhibits lower corrosion density, providing greater efficiency compared to other aluminum grades. In the case of Al 356, the potentiostatic result yields a lower value than that of other aluminum grades. Consequently, these findings suggest a tendency for favorable corrosion resistance and electrodeposition in both Al 5052 and Al 356, making them noteworthy choices in applications requiring these particular material characteristics.

Fabrication and characterization of Ni-Co-TiN/ CeO2 composite coating by ultrasonic vibration-assisted jet electrodeposition

A novel method was proposed for the fabrication of Ni-Co-TiN/ CeO2 composite coatings as protective coating by ultrasonic vibration-assisted jet electrodeposition (UVAJE). The mechanism of ultrasonic vibration on the preparation of composite coatings by jet electrodeposition is analyzed. The influences of mixed particle (micron-TiN/nano-CeO2) concentration and ultrasonic vibration on the surface morphology, phase structure, microhardness, adhesion properties, wear resistance and corrosion resistance of coatings were investigated. Coating samples were prepared by traditional jet electrodeposition (TJE), comparison with UVAJE. It was found that the mixed particles improved the performance of the coating, the ultrasonic vibration improved the surface morphology, mechanical properties and corrosion resistance of the coating compared to TJE. The coating by UVAJE had the highest microhardness, the best wear resistance and the best corrosion resistance when the concentration of mixed particles was 4 g/L. TiN/ CeO2-enhanced Ni-Co co-deposition prepared under optimal parameters opens up new avenues for replacing hard chromium, with potential applications in the defence industry, power electronics.