Passive Film Research Articles

Variation of the Passive Film on Compositionally Concentrated Dual-Phase Al0.3Cr0.5Fe2Mn0.25Mo0.15Ni1.5Ti0.3 and Implications for Corrosion

The passive film on a dual-phase Al0.3Cr0.5Fe2Mn0.25Mo0.15Ni1.5Ti0.3 FCC + Heusler (L21) compositionally concentrated alloy formed during extended exposure to an applied potential in the passive range in dilute chloride solution was characterized. Each phase, with its own distinct composition of passivating elements, formed unique passive films separated by a heterophase interface. High-resolution, surface sensitive characterization enabled chemical analysis of the passive film formed over individual phases. The film formed over the L21 phase had a higher concentration of Al, Ni, and Ti, while the film formed over FCC phase was of similar thickness but contained comparatively higher Cr, Fe, and Mo concentrations, consistent with the differences in bulk microstructure composition. The passive film was continuous across phase boundaries and the distribution of passivating elements (Al, Cr, and Ti) indicated both phases were independently passivated. Spatially resolved analysis of the surface chemistry of the dual-phase CCA revealed that the cation with the highest composition in passive film formed on the FCC phase was Cr (52.4 at. pct) and for the L21 phase was Ti (53.1 at. pct) despite the bulk concentration of each element being below 20 at. pct in their respective phases. Al, Cr, and Ti were enriched in both phases within the passive film relative to their respective bulk compositions. In parallel studies, single-phase alloys with compositions representative of the FCC and L21 phases were synthesized to evaluate the corrosion behavior of each phase in isolation. The corrosion behavior of the dual-phase alloy showed passivity evidenced by a pitting potential of 0.615 VSCE in 0.01 M NaCl. The pitting potential and other electrochemical parameters suggested a combination of behaviors of both single-phase samples, suggesting that the global corrosion behavior may be represented by a composite theory applied to phases, their area fractions, and interphase length. However, the interphase in the dual-phase CCA was a local corrosion initiation site and may limit localized corrosion protectiveness. The alloy design implications for optimization of second phase structure and morphology are discussed.

Unveiling the influence of zirconium on the corrosion behavior of Fe-36Ni Invar alloy

The influence of zirconium (Zr) on the corrosion resistance of Fe-36Ni Invar alloy in a 3.5 wt% NaCl solution was systematically investigated. Results indicated that adding Zr promoted the formation of Zr-bearing intermetallic compounds (Ni7Zr2 and Ni2Zr). The phases suppressed the grain growth and numerous dislocations were enriched around the Ni-Zr phases. Unfortunately, the incorporation of Zr into Fe-36Ni Invar alloy impaired corrosion resistance. The marked disparity in Volta potential between the Ni-Zr phases and the matrix signified the existence of micro-galvanic coupling, which caused the matrix to dissolve preferentially. Furthermore, the matrix around the Ni-Zr phases possessed high dislocation density, promoting the emergence of local galvanic corrosion. The introduction of Zr also decreased the protectiveness of the passive film, which was ascribed to the reduction of the thickness of the passive film and the beneficial oxide content in the passive film.

Passivation performance of Nb microalloyed rebar in concrete carbonation environments with different pH

In this study, XPS sputtering depth, SEM and electrochemical tests (CV, EIS, M-S, i-t, DPP) were used to study the structural composition and formation mechanism of surface passive film of Nb microalloyed rebar in SCPS with different pH. The results showed that after passivation for 10 d in SCPS with different pH, compared with CS rebar, the stability and compactness of surface passive film of 34Nb rebar gradually increased with the decreases of pH. Firstly, with the decreases of pH, the outer layer of surface passive film of 34Nb rebar was composed of Fe oxides and Fe hydroxides, and the inner layer was composed of Fe oxides and Nb oxides, thus increasing the mass ratio of Fe3+/Fe2+ and Nb2O5/(NbO2 + NbO). Secondly, with the decreases of pH, the addition of Nb promoted the formation of Fe oxides in 34Nb rebar, obtaining the excellent Rct, Ecorr and Ep. Finally, with the decreases of pH, the addition of Nb promoted the enrichment of Nb oxides in 34Nb rebar, inhibiting the degradation of Fe oxides, and the passive film exhibited the P-N type semiconductor, thus significantly decreasing the carrier density and enhancing the passivation rate of 34Nb rebar.

On corrosion and passivity of Inconel alloy 625 in HNO3 solution

Exploring the passivity and electrochemical behavior of Inconel alloy 625 in nitric acid solution could open up possibilities for potential applications, either in bulk form or as claddings. Hence, this research investigates corrosion behavior and passivity of Inconel alloy 625 in nitric acid solutions of varying concentrations (0.01–1.00 mol/L) using a range of analytical techniques, including potentiodynamic polarization testing, chronoamperometry measurement, Mott-Schottky (MS) analysis, X-ray diffraction (XRD) approaches, and point defect modeling (PDM). Results demonstrate that corrosion current density does not necessarily decrease with increasing electrolyte concentration (Please check it out). Additionally, the alloy exhibits higher passive film transpassive potentials in more concentrated solutions. Potentiostatic polarization tests reveal an increase in steady-state current densities attributed to the passive films formed in more concentrated solutions. Lower electrolyte concentrations lead to the formation of more intact bilayered passive films. In this context, the formation of passive films is elucidated by examining the generation and annihilation of point defects. The semiconducting behavior of passive layers is further examined through XRD patterns and electrochemical properties. According to PDM, the diffusivity of point defects within the passive films and their respective donor densities can be closely correlated.

Passive behavior of TNB intermetallic and Inconel 625 in electrochemical machining

The TNB alloy, a novel lightweight material, shows great potential for application in crucial aero-engine parts. This paper reveals the passive behavior of TNB alloy in electrochemical machining (ECM), Inconel 625 alloy was used for comparison. The polarization curve shows that TNB and Inconel 625 alloys have obvious passivation phenomenon at the passivation potential. Research reveals that the passive film structure of TNB alloy comprises a compact layer (about 7 nm) and a loose layer (about 13 nm), with significantly higher corrosion resistance in the compact layer compared to the loose layer. In contrast, the passive film structure of Inconel 625 alloy is a single layer with a thickness of approximately 11 nm. It was also found that the passive film composition for TNB alloy is TiO2, Al2O3, and Nb2O5. The composition of passive film for Inconel 625 alloy is NiO, Ni(OH)2, Cr2O3, MoO3, Nb2O5, FeO, and Fe2O3, and the content of Ni and Cr is high. TNB alloys exhibit uneven and loose lamellar morphology at low current densities, but can reach Ra 0.15 μm at greater than 15 A/cm2. There are always some disordered carbides rich in Nb and Mo on the surface of Inconel 625 alloy. Quantitative models were developed for both alloys to describe their electrochemical dissolution behavior.

Electrochemical corrosion behavior and passive film properties of Fe2Ni2CrV0.5Nbx (x=0.2, 0.4, 0.6, 0.8) eutectic high-entropy alloy coating prepared by laser cladding

The phase composition, microstructure morphology, and corrosion behavior of Fe2Ni2CrV0.5Nbx (x=0.2, 0.4, 0.6, 0.8) eutectic high-entropy alloy (EHEA) coatings produced via laser cladding were investigated. The research delved into discerning the phase structures and microstructural variations of the EHEA coatings concerning differing Nb compositions. The findings highlighted a direct correlation between Nb content and the volume fraction of the eutectic structure, specifically the FCC/Laves phases. Electrochemical evaluations, including diverse tests such as potentiodynamic polarization, electrochemical impedance spectroscopy, cyclic polarization, Mott-Schottky measurements, and X-ray photoelectron spectroscopy, revealed distinct corrosion behaviors among the EHEA variants. Notably, the Fe2Ni2CrV0.5Nb0.2 coating exhibited relatively superior corrosion resistance compared with Fe2Ni2CrV0.5Nbx (x=0.4,0.6,0.8) coatings, attributed to its lower corrosion current density (Icorr) and the formation of a thicker passive film with prolonged passivation duration. Conversely, the Fe2Ni2CrV0.5Nb0.8 coating, characterized by increased eutectic structures and grain boundary density, yielded a thicker yet non-uniform passive film with higher vacancy defects. This comprehensive exploration into the corrosion behavior and passive film properties of these EHEA coatings provides a reference for designing materials that hold promising implications for future corrosion-resistant material development in industrial parts repair applications.

Reducing corrosion and hydrogen gas release inside an alkaline zinc-air battery by employing ionic liquid

Zn–air batteries are a promising route that might be used in a range of energy sectors. Significant disadvantages, such as passive film and hydrogen gas evolution (HGE) in alkaline corrosive medium; restrict the possible usage of Zn–air batteries. To address these problems and increase the performance of zinc-air batteries, an ionic liquid (tris(2hydroxyethyl) hydroxymethylammonium methyl sulfate [IL]+[MS]-) has been used in this study. The usage of [IL]+[MS]- in 7.0 M KOH solution has a considerable effect on suppressing hydrogen gas creation, with an effectiveness of 86.2 %. Increasing the depth of the Bode-phase angle and the charge transfer resistance by adding [IL]+[MS]- also indicates a slower hydrogen gas production rate. The application of the [IL]+[MS]- additive improves the zinc-air battery's specific discharge capacity and capacity retention. To support these findings, SEM/EDX has been used to analyze the morphological features of Zn anodes in various electrolytes.

Corrosion behavior of novel Ti6422 alloy with equiaxed structure and lamellar structure in HCl solution

This study systematically investigated the electrochemical corrosion and static immersion corrosion behavior of the novel Ti6422 (Ti-6Al-4V-2Mo-2Fe) alloy with equiaxed (EM) and lamellar structure (LM) in HCl solution. The differences in corrosion performance between EM and LM samples were analyzed based on the characteristics of the passive film and substrate microstructure. Results indicated that the LM sample contained higher contents of TiO₂, Al₂O₃, and MoO₃ with higher stability compared with the EM sample, and the thickness of passive film was approximately twice that of the EM sample. Additionally, the donor density of LM sample was lower than EM sample. These findings indicate that the passive film on LM samples is thicker, with fewer defects and higher density. Electrochemical corrosion results revealed that the corrosion current of LM samples was lower and the polarization resistance was higher than these of EM samples, both suggesting superior corrosion resistance of LM samples. Immersion corrosion further confirmed that the LM sample had a lower corrosion rate. The enhanced corrosion resistance in LM samples was primarily due to higher content of corrosion-resistant β phase. Conversely, the numerous micro-galvanic cells between αs precipitates and adjacent β phase in EM samples weakened the corrosion resistance. Overall, these results demonstrated that regulating microstructure through heat treatment is an effective strategy for improving corrosion resistance of titanium alloys.

Effect of discharge thermal action in ECDM on electrochemical behaviours of matrix material and its recast layer in glycol-based solution

The interaction between thermal and electrochemical corrosion in the ECDM process remains unclear. This study clarifies the effect of discharge thermal action on electrochemical corrosion. Real-time temperature curves indicate that the solution temperature in the electrochemical corrosion zone increased significantly due to discharge thermal action. The corrosion resistance of the recast layer’s passive film is superior to that of the matrix due to the enrichment of Cr2O3. As the electrolyte temperature rises, the passive film thickens but shows lower polarization resistances and poorer corrosion resistance due to a loose and weak structure. The matrix material and its recast layer dissolved uniformly, resulting in a considerably flat surface in a glycol-based solution, with enhanced levelling efficiency due to discharge thermal action.

Enhancing mechanical and anti-corrosion properties in a L12 nanoprecipitates reinforced Fe35.4Ni24Cr21Co9Mo2Cu1.6Al3Ti4 multi-principal element alloy via tailoring grain size

A Fe35.4Ni24Cr21Co9Mo2Cu1.6Al3Ti4 multi-principal element alloy (MPEA) reinforced by L12 nanoprecipitates was fabricated with four different grain sizes (~19, ~50, ~127 and ~361 μm) to optimize mechanical and corrosion properties. All samples exhibit a similar microstructure, showing spherical L12 nanoprecipitates embedded in the FCC matrix at grain interiors, accompanied by a small fraction of plate-like L12 and B2-ordered phases at grain boundaries. As grain size decreases, both yield strength and ultimate tensile strength progressively increase, while ductility decreases. The sample with a grain size of ~50 μm demonstrates the most excellent combination of strength and ductility, displaying a yield strength of ~700MPa, an ultimate tensile strength of ~1130MPa, and a total elongation of ~29.4%. Concurrently, corrosion resistance in 3.5wt.% NaCl improves as grain size decreases from ~361 μm to ~50 μm, but notably deteriorates at ~19 μm. These results suggest that the L12 nanoprecipitates reinforced Fe35.4Ni24Cr21Co9Mo2Cu1.6Al3Ti4 MPEA with grain size of ~50 μm has achieved outstanding combination of mechanical and anti-corrosion properties. Precipitation strengthening and grain boundary strengthening are responsible for the enhanced mechanical properties in the studied samples. Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) revealed that the passive film on the ~50 μm grain size sample is the thickest (3.09nm), composed primarily of Cr2O3 and Fe2O3, which acts as an effective barrier against Cl- penetration. In a word, tailoring grain size proves to be an effective means to achieve enhanced mechanical and anti-corrosion properties.

Microstructure and corrosion properties of CrMnFeCoNi high entropy alloy coating by temperature field-assisted laser cladding

The CrMnFeCoNi high entropy alloy coatings were prepared on the surface of Q345 steel using a temperature field-assisted laser cladding process, and the effects of the applied temperature field on the cladding coatings were studied. The microstructures and corrosion morphologies of the coatings were observed, and the elemental distribution, hardness, effective elastic modulus, electrochemical corrosion performance, and corrosion products of different coatings were analyzed. The results show that the porosity of the HEA coatings prepared with a temperature field is reduced to below 50 % of the initial level. The microstructure of the coating changed, with the nanoindentation hardness of the coating increasing by up to 0.55 GPa, enhancing the mechanical properties. Among all the coatings, the coating prepared at 250 °C temperature field exhibited the best corrosion resistance, with corrosion potential and current density of −0.27 V and 0.15 μA/cm2, respectively, improving the corrosion potential by 0.1 V and reducing the current density by 1.08 μA/cm2 compared to the sample prepared at room temperature. After incorporating the temperature field, the stability of the passive film on the coating during corrosion improved, and the nucleation rate of pitting decreased. Therefore, incorporating an appropriate temperature field during laser cladding can effectively enhance the overall performance of the CrMnFeCoNi HEA coating.

Gallocyanine-mediated non-covalent functionalization and exfoliation of h-BN for efficient anticorrosion reinforcement of waterborne epoxy coating

Hexagonal boron nitride (h-BN) is commonly used to enhance the anti-corrosion of organic coatings due to its excellent barrier properties, dielectricity and mechanical robustness. However, the bulky h-BN tends to create poor dispersibility and interfacial compatibility problems with the resin matrix, leading to coating cracking and failure. H-BN nanosheets exfoliated by conventional methods only provide passive barrier effect with coatings at the initial stage of corrosion. Herein, we used a mussel-inspired non-covalent functionalization strategy, using the catechol groups and heteroaromatic ring structure of gallocyanine to achieve the functionalization and exfoliation of h-BN through ball milling, and obtained ultra-thin h-BN@G nanosheets. Remarkably, spare gallocyanine can further suppress the erosion, whose inhibition efficiency is 95.48 % at the concentration of 100 mg/L in 1 M HCl within 9 h. Typically, after 105 days of immersion in 3.5 wt% NaCl solution, the low-frequency impedance of h-BN@G/WEP coating is still as high as 1.45 × 109 Ω cm2, which is two orders of magnitude higher than that of the pure coating. The superior long-term anti-corrosion capacity can be ascribed to the triple protection of enhanced shielding property of desirable-exfoliated h-BN, passivation films adsorbed on the metal and coordination bonds formed between gallocyanine and the iron to resist the active corrosion. Our work offers an innovative idea for the functionalization and exfoliation of other lamellar materials, which can be applied to the implementation of long-lasting anti-corrosion coatings.

Rapid fabrication and corrosion behavior of 3D-porous Cu-Al-Si compounds via low-energy self-exothermic reaction

In this study, porous Cu-Al-Si intermetallic compounds with three-dimensional structures were rapidly prepared by a novel self-exothermic reaction. By this method, Si was successfully solid-solved into CuAl intermetallic compounds and achieved better fusion with them. The effects of Si addition on their oxidation resistance and corrosion resistance were compared. The findings indicate that the minimum weight gain of the Cu-Al-Si product is only 1.48% after oxidation at 800 °C for 288h. Si facilitates the creation of a continuous Al2O3 protective layer on the surface of the porous Cu-Al-Si intermetallics skeleton, thereby preserving its internal structure while significantly enhancing its oxidation resistance. The incorporation of Si to Cu-Al intermetallics enhances the stability of the passivation film on the material's surface, increases the resistance of the passivation film, and effectively restricts the electrochemical reaction between the material and the corrosive medium.

Effect of elastic stress on anodic dissolution behavior of TA2

The anodic dissolution behaviors of TA2 under elastic stress in acidic 3.5 % NaCl solution with or without 5 mM NaF were investigated using in-situ scanning electrochemical microscopy (SECM), along with polarization curve, SEM and AFM. The results indicated that the dissolution of the passive film in 3.5 % NaCl solution was accelerated under 100 MPa, and more resistant to dissolve under 200 MPa. In presence of 5 mM NaF, the stress intensified the dissolution of the matrix. Specifically, 100 MPa stress increased the corrosion difference between different grains, while 200 MPa stress made the corrosion of TA2 more uniform.

Towards electrochemical machining of powder superalloy René 88DT with high surface integrity in different solvent-based electrolytes

Electrochemical machining (ECM) presents numerous applications in the production of aero-engine components. The effects of current density on surface quality during ECM of René 88DT in NaCl-ethylene glycol and NaNO3-aqueous solutions was investigated here. The results indicated that the René 88DT surface has lower sensitivity to current density and more homogeneous electrochemical dissolution in NaCl-glycol solution than in NaNO3-aqueous solution, which results in the suppression of stray corrosion and consistently high surface quality regardless of current density. These strengths are attributed that C2H5O2- and Cl- ions replace OH– ions and combine with alloy ions to form solubles and complexes, which prevent the formation of obstructive passive film, oxide layer, and insoluble electrolytic products. The electrochemical dissolution model in two solutions was established. Furthermore, the high tensile strength and precision machinability of René 88DT in NaCl-glycol solution were also demonstrated.

Microstructure evolution and oxidation resistance of plasma sprayed AlSi-doped AlCoCrFeNi coatings with post-annealing

High entropy alloy (HEA) coatings of equimolar AlCoCrFeNi typically exhibit a lower oxidation rate at high temperatures by forming a protective passivation film. However, the metal elements consumption during long-term oxidation limitted the application. In this work, AlCoCrFeNi HEA coatings doped by AlSi as a supplement to passivation elements were prepared by atmospheric plasma spraying (APS), and AlSi capsules were diffused uniformly into the coating through annealing treatment to offset the element consumption during high-temperature oxidation. Results showed that annealing promoted Al and Si atoms diffusing into the solid solution, which stabilized BCC and inhibited FCC formation. During the oxidation at 900 °C, a protective Al2O3 film was formed on the coating surface, and AlSi capsules continuously transported Al ions to the consumption zone and reduced oxidation rate to 0.0015 g/cm2. The HEA coating doped by passivation element capsules provided a new approach for the design of novel antioxidant coatings.

Preparation process, surface properties and mechanistic study of HVAF-sprayed CoCrFeNiMo0.2 high-entropy alloy coatings

The objective of this study is to develop infrared reflective coatings with excellent service performance in extreme environments, aimed at reducing system energy consumption and enhancing service life. In this work, CoCrFeNiMo0.2 high-entropy alloy (HEA) powder was deposited on the 316 L stainless steel (SS) substrate using High-Velocity Air Fuel (HVAF) thermal spray technology. The microstructure, mechanical properties, infrared reflectivity, and corrosion resistance of the coatings under different spraying parameters were investigated and compared with those of the substrate. Computational Fluid Dynamics (CFD) simulation was employed to analyze the influence of HVAF spraying parameters on flame characteristics and particle flight behavior, providing guidance for optimizing the spraying process and explaining underlying mechanisms. Results demonstrated that adjusting parameters such as propane and air pressure, spraying distance, and powder feed rate could produce dense coatings with <1 % porosity. The microhardness of the coatings was approximately 1.8 times that of the substrate, and the bonding strength between the coating and the substrate is increased to 39.4 MPa. Additionally, the near-infrared reflectivity of the coatings was significantly higher than that of the substrate, with an enhancement of 18.7 %. Coatings sprayed under different parameters exhibited superior passivation and pitting corrosion resistance compared to the substrate in 3.5 wt% NaCl and 1 mol/L HCl solutions. Optimization of spraying parameters further enhanced the protective capability of the passivation film and corrosion resistance. Consequently, CoCrFeNiMo0.2 HEA coatings prepared by HVAF spraying technology demonstrate excellent comprehensive performance, holding promising potential for industrial applications.

Synthesis and characterization of ZnO and CuO coatings for antibacterial and antiviral applications

Copper oxide (CuO) and Zinc oxide (ZnO), coating have attracted attention for their potential antiviral properties, including their ability to combat virus. This study focuses on the development and characterization of self-disinfecting surface passivation films composed of CuO and ZnO, obtained using the spin-coating technique. The research aims to develop surfaces that can actively eliminate harmful microorganisms, reducing the risk of infections, while also offering strong mechanical resistance and adhesion to withstand external factors, which is crucial for ensuring long-term effectiveness. Additionally, the microstructural properties of the elaborated films were analyzed using SEM/EDS, which stands for Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy and X-Ray diffraction analysis (XRD). The mechanical behavior was assessed through Vickers hardness and scratch resistance tests. It was found a dense and homogeneous thin films. The hardness of CuO and ZnO films were 11.14 ± 0.04 GPa, and 8.89 ± 0.04 GPa respectively. Therefore, scratching tests revealed high adhesion properties with a critical load LC1 of 1.89 ± 0.02 N and 1.04 ± 0.02 N for CuO and ZnO films respectively. Then, this study revealed that CuO and ZnO films exhibit excellent antimicrobial activity against Staphylococcus aureus ATCC 29213, as well as outstanding antiviral activity against the HSV-2 virus.

The effects of ECAP, Mn and Ca elements on the microstructure and corrosion properties of magnesium alloys were investigated

In this study, through reasonable composition design, three elements of Zn, Mn and Ca, which are harmless to human body, were selected for alloying magnesium. The effects of ECAP treatment on the microstructure and corrosion properties of Mg-4Zn-1Mn-0Ca, Mg-4Zn-1Mn-0.2Ca and Mg-4Zn-0Mn-0.2Ca alloys were studied. The corrosion mechanism of Mg-Zn-Mn-Ca alloys with different components in Simulated. Body fluid (SBF) was analyzed by weight loss method and electrochemical test. The grains and the second phase were refined by Equal Angular Channel Pressing (ECAP). It was found that after 8 ECAP deformations, the microstructure of the alloy was refined and more uniform than that of the extruded alloy. The corrosion resistance of the Mg-Zn-Mn-Ca alloy after ECAP deformation in simulated body fluids was studied by electrochemical testing techniques, immersion experiments and observation of the microstructure and morphology of corrosion products. The relationship between microstructure characteristics, the behavior of the magnesium metal matrix and the properties of corrosion products was revealed. The results show that the microstructure of the alloy is refined and the corrosion resistance is improved with the increase in extrusion passes in the SBF solution. The corrosion resistance of magnesium alloy after 8 ECAP deformation is the best, showing small Icorr and large Rt. With the extension of the soaking time, the surface of the alloy will form a passivation film, which will protect the matrix and avoid further corrosion of the alloy. It is found that in SBF, the corrosion of the alloy surface is mainly pitting, which indicates that Ca2+, HCO3- and HPO42- in SBF can reduce the corrosion rate of magnesium alloy.

A novel BCC-L21-BCC hierarchical heterostructure high entropy alloy with excellent corrosion resistance and mechanical properties in as-cast state

In this paper, a novel as-cast CrFeNiAl0.35Si0.1Ti0.1 high entropy alloy (HEA) with micron-to-nano hierarchical heterostructure was designed, and its microstructure, mechanical properties and corrosion resistance have been systematically investigated. It is found that, this novel HEA exhibits well-dispersed L21 phases with various sizes from micron-scale to nano-scale in the BCC matrix, while nano-sized BCC lamellas could also emerge in the L21 phase with large diameter. Moreover, this HEA exhibits not only excellent corrosion resistance in 3.5 wt.% NaCl solution that close to super-stainless steels, but also high mechanical properties combining yield strength of 1712±56 MPa, compressive plasticity of 21.2%±0.5% and hardness of ∼560 Hv. Such outstanding comprehensive properties for this HEA are possibly resulted from the complex hierarchical BCC-L21-BCC heterostructure with stable passive film and low diversity in work function between different phases. This work provides a novel route in the development of high-performance corrosion-resistant HEAs for structural and coating applications.