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Inorganic, organic, and metallic coatings have received much attention due to their great protection applications in oil and gas industries and their development through finding eco-friendly materials for the coatings. Their unique structure, low cost, and facile synthesis are some of the few properties of graphitic carbon nitride (g-C3N4) materials that make them useful in a number of applications. Moreover, g-C3N4 offers exceptional chemical and thermal stability and a high specific surface area, and it is well known for its outstanding biocompatibility and biological activity. Numerous investigations have reported various types of C3N4-incorporated coatings that have enhanced corrosion, wear, and mechanical resistance properties. This review highlights the new applications of g-C3N4 (standalone, in an alloy, or composite) as a coating in the wear and corrosion protection fields. Furthermore, a strong focus on the structure, unique properties, and preparation technique of g-C3N4 are summarized, especially in metallic coatings, which is a highly novel trend. Lastly, various important issues based on current research are proposed for future prospective work that should be further studied in this attractive research topic. [ABSTRACT FROM AUTHOR]

Bonded permanent NdFeB magnets are useful in numerous applications, including electric vehicles, and the demand is steadily increasing. A major drawback is corrosion due to inadequate wetting of the magnetic particles by liquid polymers such as polyphenylene sulfide or polyamide. Recently reported methods for corrosion inhibition are summarized, and their applicability is critically evaluated. The phosphorylation of magnetic particles inhibits corrosion but does not enable appropriate properties in harsh environments. The same applies to metallic coatings, which usually contain aluminum and zinc. Advanced epoxy adhesives are a promising solution, although some authors have reported inadequate corrosion resistance. The application of composite coatings seems like an appropriate solution, but the exact mechanisms are yet to be studied. [ABSTRACT FROM AUTHOR]

Protective coatings are typically applied to enhance their resistance to corrosion. There is considerable research on the corrosion resistance of coated casings. However, few research studies have focused on the erosion resistance on coated casings. In this work, the erosion resistance of resin- and metallic-coated casings in liquid–solid two-phase fluids were investigated using a self-made erosion facility. The results show that the resin coating tends to peel off the material base in the form of brittle spalling or coating bulge in the high-speed sand-carrying liquid. Both resin and metallic coatings were broken through within 20 min in a liquid–solid two-phase flow environment. Compared to resin coatings, metallic coatings exhibit weaker erosion resistance in similar liquid–solid flow. Through the analysis of experimental results and fitted curves, empirical constants for materials and sand content influencing factors were determined using non-dimensional processing. The erosion prediction model of metallic coatings and resin coatings was established based on the ECRC/Zhang model with the change in flow rate, angle, and sand content. This research contributes to a better understanding of the erosion resistance performance of casings used in oil and gas fields, thereby contributing to potential improvements in their production. [ABSTRACT FROM AUTHOR]

Our investigations show that electrochemical corrosion of copper is faster than electrochemical corrosion of aluminium at temperatures below 180°C and electric current density 3,000 A/m2 (or 30 A/dm2=3 mA/mm2). We have obtained that aluminium anodes (cylindrical or spherical) dissolve into concentrated NaCl solution during electrolysis more rapidly with temperature increasing while copper anodes (cylindrical or spherical) dissolve more slowly with temperature increasing from room temperature to temperature 180°C. Electric current value also increases with temperature increasing. Really, such result is unexpected. General quantity of the H+ and Cl- ions decreases during electrolysis at all temperatures since the H2 and Cl2 gases are formed near electrodes. It decreases electric current value on 1.3%. General quantity of the Cu+ and Cu2+ ions decreases with temperature increasing too. We guess that one reason only should be for electric current value increasing: average charge of copper ions increases from +1 at room temperature to +1.5 at 100°C and to +2 at 180°C while charge of aluminium ions remains the same +3. Corresponding mathematical model is proposed for the analysis, and literature experimental data are used too.

Due to the emerging resistance of microorganisms and viruses to conventional treatments, the importance of self-disinfecting materials is highly increasing. Such materials could be silver or its nanoparticles (AgNPs), both of which have been studied for their antimicrobial effect. In this study, we compared the biological effects of AgNP coatings with and without a plasma-polymerized hexamethyldisiloxane (ppHMDSO) protective film to smooth silver or copper coatings under three ambient conditions that mimic their potential medical use (dry or wet environments and an environment simulating the human body). The coatings were deposited on 3D printed polylactic acid substrates by DC magnetron sputtering, and their surface morphology was visualized using scanning electron microscopy. Cytotoxicity of the samples was evaluated using human lung epithelial cells A549. Furthermore, antibacterial activity was determined against the Gram-negative pathogenic bacterium Pseudomonas aeruginosa PAO1 and antiviral activity was assessed using human rhinovirus species A/type 2. The obtained results showed that overcoating of AgNPs with ppHMDSO creates the material with antibacterial and antiviral activity and at the same time without a cytotoxic effect for the surrounding tissue cells. These findings suggest that the production of 3D printed substrates coated with a layer of AgNPs-ppHMDSO could have potential applications in the medical field as functional materials. [ABSTRACT FROM AUTHOR]

Nickel-based coatings are well known for their good corrosion resistance performance. However, these materials suffer from inferior mechanical properties that limit their wider application. This work investigates the synthesis, and performs an exhaustive characterization, of Ni–P–B4C nanocomposite coatings developed through conventional electrodeposition using a modified Watts bath. The study examines the effect of an increase in the concentration of boron carbide nanoparticles (BCNPs) on the structural, morphological, topographical, mechanical and electrochemical properties of the nanocomposite coating. Vickers microhardness tester and nanoindentation technique were utilized to elucidate the role of BCNPs in modifying the mechanical response of nanocomposite coatings. Furthermore, corrosion resistance of the nanocomposite coatings was investigated through d.c potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Comparison of the properties of the developed coatings revealed the remarkable improvement in the properties of Ni–P–B4C nanocomposite coatings when compared to the bare mild steel substrate and the Ni–P coatings. The enhanced corrosion resistance and superior mechanical properties of Ni–P–B4C nanocomposite coatings make them attractive for many industries. Based upon the experimental findings, a possible mechanism for the synthesis and improved corrosion resistance of Ni–P–B4C nanocomposite coatings was also proposed.

Due to the emerging resistance of microorganisms and viruses to conventional treatments, the importance of self-disinfecting materials is highly increasing. Such materials could be silver or its nanoparticles (AgNPs), both of which have been studied for their antimicrobial effect. In this study, we compared the biological effects of AgNP coatings with and without a plasma-polymerized hexamethyldisiloxane (ppHMDSO) protective film to smooth silver or copper coatings under three ambient conditions that mimic their potential medical use (dry or wet environments and an environment simulating the human body). The coatings were deposited on 3D printed polylactic acid substrates by DC magnetron sputtering, and their surface morphology was visualized using scanning electron microscopy. Cytotoxicity of the samples was evaluated using human lung epithelial cells A549. Furthermore, antibacterial activity was determined against the Gram-negative pathogenic bacterium Pseudomonas aeruginosa PAO1 and antiviral activity was assessed using human rhinovirus species A/type 2. The obtained results showed that overcoating of AgNPs with ppHMDSO creates the material with antibacterial and antiviral activity and at the same time without a cytotoxic effect for the surrounding tissue cells. These findings suggest that the production of 3D printed substrates coated with a layer of AgNPs-ppHMDSO could have potential applications in the medical field as functional materials.

Metallic additive manufacturing is expeditiously gaining attention in advanced industries for manufacturing intricate structures for customized applications. However, the inadequate surface quality has inspired the inception of metallic coatings through additive manufacturing methods. This work presents a brief review of the different genres of metallic coatings adapted by industries through additive manufacturing technologies. The methodologies are classified according to the type of allied energies used in the process, such as direct energy deposition, binder jetting, powder bed fusion, hot spray coatings, sheet lamination, etc. Each method is described in detail and supported by relevant literature. The paper also includes the needs, applications, and challenges involved in each process. [ABSTRACT FROM AUTHOR]

This work reports yarn pull-out studies of commercially available Kevlar® KM2+ individual yarns coated with metallic layers (copper, aluminum, aluminum nitride and silver) via a directed vapor deposition process. The uncoated control and metal-coated Kevlar® yarns are hand-woven into fabric swatches for quasi-static pull-out experiments. To perform these experiments, a yarn pull-out fixture is custom-designed and fabricated to apply transverse pre-tension to the fabric. Three levels of transverse pre-tensions are studied at 100 N, 200 N, and 400 N. The results showed that both peak pull-out force and energy absorption during the pull-out process increase with increase in transverse pre-tension. All the metal-coated groups showed an approximately 200% increase in peak pull-out force and a 20% reduction in tenacity compared to uncoated control. Furthermore, all the metal-coated groups showed an increase in energy absorption, with aluminum-coated yarns showing the highest increase of 230% compared to control. These results suggest enhanced frictional interactions during yarn pull-out in metal-coated yarns compared to uncoated control as evidenced by the surface roughness profile of individual fibers and inter-yarn frictional calculations. [ABSTRACT FROM AUTHOR]

Compressible metallic porous materials (CMPMs) have great potential for development in the energy and environmental fields. However, the scale-up preparation of CMPMs with stable metal layers, excellent elasticity, and multifunctionality remains exceedingly challenging. In this study, we designed a novel strategy with the aid of polymer-assisted metal deposition to synthesize metallic porous wood (Ni-PW) with a hierarchical cellular structure and excellent elasticity. Our approach can produce highly compressible MPW using intrinsically porous delignified wood with only 15.16% strain loss under a large compressive strain of 40% after 1000 loading-unloading cycles and 129.4 μm of the average porous size of the Ni-PW measured by mercury injection method. The resulting Ni-PW displays excellent antibacterial properties for Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) and electric conductivity (Resistance < 7 ty), which renders great potential in energy and environmental applications. This research provides a new insight into the fabrication of CMPMs in a cost-effective (~56.5 ¥ m−2) and scalable way. [ABSTRACT FROM AUTHOR]

This paper describes the use of Supersonic Laser Deposition (SLD) to manufacture nickel/graphite composite coatings on titanium and aluminium substrates. Laser heating is critical for depositing coatings containing up to 13.3 vol% graphite. For a given feedstock composition, the resulting graphite content and average size of the graphite particles retained in the coating increases with laser power, until substrate melting occurs. The effect of the powder type, feedstock composition, and process conditions on coating structure is characterized. The friction and wear behaviour of selected coating compositions is examined. Nickel coatings containing 13.3 vol% graphite demonstrated self-lubricating behaviour with a stable coefficient of friction below 0.14 in pin-on-disc testing. [ABSTRACT FROM AUTHOR]

This work reports yarn pull-out studies of commercially available Kevlar® KM2+ individual yarns coated with metallic layers (copper, aluminum, aluminum nitride and silver) via a directed vapor deposition process. The uncoated control and metal-coated Kevlar® yarns are hand-woven into fabric swatches for quasi-static pull-out experiments. To perform these experiments, a yarn pull-out fixture is custom-designed and fabricated to apply transverse pre-tension to the fabric. Three levels of transverse pre-tensions are studied at 100 N, 200 N, and 400 N. The results showed that both peak pull-out force and energy absorption during the pull-out process increase with increase in transverse pre-tension. All the metal-coated groups showed an approximately 200% increase in peak pull-out force and a 20% reduction in tenacity compared to uncoated control. Furthermore, all the metal-coated groups showed an increase in energy absorption, with aluminum-coated yarns showing the highest increase of 230% compared to control. These results suggest enhanced frictional interactions during yarn pull-out in metal-coated yarns compared to uncoated control as evidenced by the surface roughness profile of individual fibers and inter-yarn frictional calculations.

The noncoded aromatic 3,4-dihydroxy-L-phenylalanine (DOPA) amino acid has a pivotal role in the remarkable adhesive properties displayed by marine mussels. These properties have inspired the design of adhesive chemical entities through various synthetic approaches. DOPA-containing bioinspired polymers have a broad functional appeal beyond adhesion due to the diverse chemical interactions presented by the catechol moieties. Here, we harnessed the molecular self-assembly abilities of very short peptide motifs to develop analogous DOPA-containing supramolecular polymers. The DOPA-containing DOPA-DOPA and Fmoc-DOPA-DOPA building blocks were designed by substituting the phenylalanines in the well-studied diphenylalanine self-assembling motif and its 9-fluorenylmethoxycarbonyl (Fmoc)-protected derivative. These peptides self-organized into fibrillar nanoassemblies, displaying high density of catechol functional groups. Furthermore, the Fmoc-DOPA-DOPA peptide was found to act as a low molecular weight hydrogelator, forming self-supporting hydrogel which was rheologically characterized. We studied these assemblies using electron microscopy and explored their applicative potential by examining their ability to spontaneously reduce metal cations into elementary metal. By applying ionic silver to the hydrogel, we observed efficient reduction into silver nanoparticles and the remarkable seamless metallic coating of the assemblies. Similar redox abilities were observed with the DOPA-DOPA assemblies. In an effort to impart adhesiveness to the obtained assemblies, we incorporated lysine (Lys) into the Fmoc-DOPA-DOPA building block. The assemblies of Fmoc-DOPA-DOPA-Lys were capable of gluing together glass surfaces, and their adhesion properties were investigated using atomic force microscopy. Taken together, a class of DOPA-containing self-assembling peptides was designed. These nanoassemblies display unique properties and can serve as multifunctional platforms for various biotechnological applications.

Thermoelectric power plants that use mineral coal show high wear in heat exchanger due to the action of several damage mechanisms associated with the impact of hard particles from the residue of burnt coal, the ashes. The employment of coatings should be given into consideration particularly for critical components, which are subject to severe erosive conditions is one of the solutions. However, the choice of material will depend on several factors, including the properties of aggressive ashes. This paper aims to characterize ashes generated by a Brazilian coal-based power plant and a FeCrNbNi-based metallic coating obtained by the electric arc spraying process. No trace of sulfur content was found in fly ashes and it was defined that wear is mainly related to the impact and energy of hard particles are the leading causes of degradation in coal-fired boiler equipment. According to the assessment, applied coating showed (5 ± 2)% by volume of pores and cracks, with 1.6% of oxides after the spraying process and hardness 35% greater than ash particles. Preliminary results in field operation suggest that the material showed relatively low wear compared to the original substrate and showed great applicability in controlling material deterioration for this purpose.

This paper presents a study on advanced material designs suitable for lightweight space packaging structures. During this study, several material designs were proposed, evaluated and in the end three packaging structures were designed, manufactured and validated through a test campaign. The material designs proposed consisted in hybrid laminates composed of a composite substrate and integrating metallic foils with high atomic number (Low Z - High Z - Low Z concept) and metallic coatings to increase the structure’s protection against harsh space conditions. The packaging structure design selected was a 2U CubeSat. A FEM analysis was performed on two different designs which showed good mechanical resistance under static loads, and regarding the modal analysis, the natural vibration frequencies of the CubeSat were in the imposed limits (outside of the critical range of 1-125 Hz). To reproduce the dynamic environment encountered during launching stage, vibration tests were performed. The structures were validated through a test campaign (vibration tests) and their first vibration mode overcomes 100 Hz, results predicted by the FEM analysis.

The corrosion protection of Hastelloy-N alloy in LiF-NaF-KF (commonly referred to as FLiNaK) molten salt has been developed by pure Ni and Co coatings using the laser cladding technique. An immersion experiment with samples was performed in molten FLiNaK salt at 900 °C for 100 h. It was found that the corrosion rates of the pure Ni-coated specimen and the pure Co-coated specimen are 39.9% and 35.7% of that of Hastelloy-N alloy, respectively. A careful microstructural characterization indicates that a selective dissolution of the elemental Cr occurred in the surface of bare Hastelloy-N alloy, showing a severe intergranular corrosion. For pure metal-coated specimens, in contrast, only metal oxide formed during the laser cladding process dissolved into the molten fluoride salt. The dense pure metal (Ni or Co) coatings exhibit a slightly general corrosion and protect the Hastelloy-N substrate effectively. The possible corrosion mechanism for both coated and uncoated Hastelloy-N under the current experimental condition are discussed in this work. [ABSTRACT FROM AUTHOR]

Variation in the thermal conductivity of a metal-coated tri-walled carbon nanotube (3WCNT), in the presence of vacancies, was studied using non-equilibrium molecular dynamics simulations. A Two-Temperature model was used to account for electronic contribution to heat transfer. For 3WCNT with 0.5% and 1% random vacancies, there was 76%, and 86% decrease in the thermal conductivity, respectively. In that order, an overall ~66% and ~140% increase in the thermal conductivity was recorded when 3 nm thick coating of metal (nickel) was deposited around the defective models. We have also explored the effects of tube specific and random vacancies on thermal conductivity of the 3WCNT. The changes in thermal conductivity have also been justified by the changes in vibrational density of states of the 3WCNT and the individual tubes. The results obtained can prove to be useful for countering the detrimental effects of vacancies in carbon nanotubes.

This paper presents a study on advanced material designs suitable for lightweight space packaging structures. During this study, several material designs were proposed, evaluated and in the end three packaging structures were designed, manufactured and validated through a test campaign. The material designs proposed consisted in hybrid laminates composed of a composite substrate and integrating metallic foils with high atomic number (Low Z - High Z - Low Z concept) and metallic coatings to increase the structure's protection against harsh space conditions. The packaging structure design selected was a 2U CubeSat. A FEM analysis was performed on two different designs which showed good mechanical resistance under static loads, and regarding the modal analysis, the natural vibration frequencies of the CubeSat were in the imposed limits (outside of the critical range of 1-125 Hz). To reproduce the dynamic environment encountered during launching stage, vibration tests were performed. The structures were validated through a test campaign (vibration tests) and their first vibration mode overcomes 100 Hz, results predicted by the FEM analysis. [ABSTRACT FROM AUTHOR]

Insufficient wetting of Na on Na-β'-alumina is responsible for an increased interfacial polarization in Na-batteries if the operating temperature is below 270-300 °C. In this study, Na alloys (Na-Sn, Na-Bi and Na-In) on the ceramic surface are examined on their capability to improve the wetting with molten sodium at medium temperatures and thereby enabling operation of the cell at temperatures in the range of 105 to 150 °C. Metallic coatings with Bi or Sn confirm this improvement at a temperature of 115 °C. The overpotential of a symmetrical Na│Na-β'-alumina│Na cell is determined by galvanostatic cycling and electrochemical impedance spectroscopy and then associated to contact angle measurements. As a result, both the alloys and the metallic coatings have a positive impact on wetting and reduction of the overpotential during galvanostatic cycling. [ABSTRACT FROM AUTHOR]

In this study, the heat transfer augmentation of a two-phase closed thermosiphon (TPCT) with a thin, porous copper coating is studied and compared with an uncoated TPCT. The inner surface of the TPCT is coated using an electrochemical deposition process. The coated and uncoated TPCTs are filled with deionised water and tested with a heat input of 50 to 250 W. The heat transfer coefficient in the evaporator and condenser is assessed and compared with the thermal resistance of coated and uncoated TPCTs. The effects of the inclination angle, power input and thin copper coating on the performance of the TPCTs are explored. The heat transfer coefficient of the evaporator is found to be enhanced up to 44% at a heat flux of 10 W/m 2 for an inclination angle of 45°. TPCTs with an oxide coating are also compared to those with a metallic coating and the metal-coated TPCT was found to perform better than the oxide-coated TPCT. The effect of non-dimensional numbers, such as Bond (Bo), Webber (We), Kutateladze (Ku) and condensation (Co) numbers, with the variation of heat flux, is also investigated. [ABSTRACT FROM AUTHOR]

An Al-V alloy powder produced by high-energy ball milling has been cold sprayed on an AA2024-T3 substrate. The corrosion resistance of cold sprayed alloy, represented by the corrosion current density and pitting potential, was significantly higher than the substrate. Furthermore, a zero-resistance ammeter test revealed that the coating was anodic to the substrate, which would provide cathodic protection in any event of coating breakdown. The wear resistance of the coating was almost four times higher than that of the substrate. [Display omitted] • Successful cold spraying of ball-milled Al-V alloy powder on an AA2024-T3 substrate. • Nanocrystalline Al-V alloy coating with high solid solubility of V in Al by cold spray. • 43 times decreased corrosion current density by cold spraying Al-V alloy. • Significantly increased pitting potential and wear resistance by cold spraying. • Highly corrosion resistant and sacrificial coating. [ABSTRACT FROM AUTHOR]

A silica colloidal crystal (SCC)–polydimethylsiloxane (PDMS) composite with a heterogeneous surface of silica and PDMS was prepared by spreading a premixed PDMS solution on the 3D structured SCCs and curing the solution in-situ. Although the SCCs had a light blue color, the obtained composite of SCC and PDMS, due to the close effective refractive indexes of the materials, was colorless and transparent; the UV–vis spectra indicated a negligible effect of the added SCC on the transmittance of the PDMS sheet (1% reduction). Interestingly, the transparent composite sheet became translucent under stress and became clear again when relaxed. It was found that the wrinkles formed on the surface under stress were responsible for the optical change; and, the formation of the wrinkles was ascribed to the rigid nature of the SCC layer embedded in PDMS. We had applied this SCC/PDMS composite as a substrate to support a thin gold film of nanoscale thickness and found that the embedded SCC layer worked well as a transitional interface for bonding materials of mismatched mechanical properties. The incorporation of SCC layer significantly suppressed the crack generation and propagation of the gold film. The results demonstrated a potential approach for fabricating compliant and crackfree metallic films on polymeric substrates. [ABSTRACT FROM AUTHOR]

Ceramic particles typically do not have a sufficiently high wettability for incorporation into molten metal during aluminum matrix composite manufacturing. Metallic coatings on ceramic particles could improve their wettability by the molten aluminum and hence provide a better bonding between the reinforcement and matrix. In this study, micrometer-sized SiC particles were coated by copper, nickel, and cobalt metallic layers using electroless deposition method. These metallic layers were produced separately prior to ceramic incorporation into molten pure aluminum, in order to compare their effects on the microstructure and mechanical properties of the produced composites. The experimental results showed that copper was the most effective and nickel the least effective of these coating metals for incorporation of the SiC particles into the molten aluminum. It was additionally found that the composite, which contained the copper coated SiC particles, produced the highest microhardness and tensile strength, while that fabricated with the cobalt-coated SiC particles produced the lowest microhardness and tensile strength. [ABSTRACT FROM AUTHOR]

A theoretical model is developed to evaluate the thermal conductivity of composites made of a dielectric matrix material containing randomly oriented and aligned carbon nanofibers coated with a metallic layer. The effect of the metallic coating on the phononic thermal conductivity of the matrix material and the electron–phonon coupling inside the metallic coating are both taken into account in this model. It is shown that: (1) the metallic coating has an extraordinary effect on the enhancement of the composite thermal conductivity. For a volume fraction of 30% of fibers with radius of 50 nm and 10 nm-coating of copper, the increase in the thermal conductivity is as high as 27%, which increases significantly with the fiber volume fraction. (2) Although the thermal conductivity of silver is 453% as that of indium, the composite thermal conductivity is only increased slightly by changing an indium coating to a much more expensive silver coating, due to the relatively high thermal conductivity of these metals in comparison with the one of the matrix. (3) The composite thermal conductivity increases with the volume fraction of the fibers when their radius and the radial thermal conductivity are greater than the Kapitza radius at the matrix-coating interface and the effective thermal conductivity of the matrix, respectively. The obtained theoretical results agree fairly well with experimental data reported in the literature for the thermal conductivity along the axis of aligned carbon fibers with copper coating and embedded in an epoxy matrix. This model is expected to be valid for composites in the absence of percolation with the length-to-radius aspect ratio of fibers in the range of 10–100, and it provides theoretical guides for optimizing cost-efficient high thermal conductivity composites. [ABSTRACT FROM AUTHOR]

Zinc is a well-known sacrificial coating material for iron and co-deposition of suitable particles is of interest for further improving its corrosion protection performance. However, incorporation of particles that are well dispersible in aqueous electrolytes, such as silica particles, is extremely difficult. Here, we report a detailed study of Zn-SiO2 nanocomposite coatings deposited from a zinc sulfate solution at pH 3. The effect of functionalization of the silica particles on the electro-codeposition was investigated. The best incorporation was achieved for particles modified with SiO2-SH, dithiooxamide or cysteamine; these particles have functional groups that can strongly interact with zinc and therefore incorporate well into the metal matrix. Other modifications (SiO2-NH3+, SiO2-Cl and N,N-dimethyldodecylamine) of the silica particles lead to adsorption and entrapment only. [ABSTRACT FROM AUTHOR]

An AlCoCrFeNiY high-entropy alloy coating was prepared using air plasma spray. The cyclic oxidation behavior of the coating was investigated and compared with that of a conventional NiCoCrAlY coating. It is demonstrated that the AlCoCrFeNiY coating exhibits much stronger resistance to oxidation and spallation than the NiCoCrAlY coating when they are thermally cycled between room temperature and 1050 - 1150 °C. The difference is attributed to a much lower growth rate of the oxide scale on the AlCoCrFeNiY coating as a result of its significantly higher activation energy of oxidation and the absence of spinel. [Display omitted] • The spallation resistance of high-entropy AlCoCrFeNiY coating is highly superior to the conventional NiCoCrAlY coating. • The oxidation rate of AlCoCrFeNiY coating is much lower than that of NiCoCrAlY coating. • The activation energy of oxidation for AlCoCrFeNiY coating is much higher than that of NiCoCrAlY coating. • The formation of detrimental spinel oxides is suppressed in the early oxidation stage for the AlCoCrFeNiY coating. [ABSTRACT FROM AUTHOR]