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• The passive film properties of Ce-added AlCoCrFeNi 2.1 alloys are studied for the first time. • Ce addition is not conducive to corrosion resistance of the AlCoCrFeNi 2.1 alloy in H 2 SO 4 solution. • Ce increases the doping density and reduces the proportion of Cr oxides in the passive film. Eutectic high-entropy alloys (EHEAs), represented by AlCoCrFeNi2.1, are considered to be promising materials. However, the study of the corrosion behavior of EHEAs remains limited, which hinders further development. This study investigated the effect of Ce addition on the electrochemical behavior and passive film properties of AlCoCrFeNi 2.1 EHEAs in H 2 SO 4 solutions. The results show that the addition of Ce changed the properties of the passive film formed on the alloys, resulting in reduction in the proportion of Cr 2 O 3 , and thereby reduced the corrosion resistance. Moreover, a higher Ce content in the EHEAs was found to correspond to a more pronounced deterioration in corrosion resistance. Compared with the film formed at 0.2 V vs SCE , the film formed at 0.5 V vs SCE exhibited more optimal physicochemical properties, leading to a decrease in the passive current density. Notably, Ce was absent in the film formed at 0.2 V vs SCE , but present at 0.5 V vs SCE. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to prepare a multifunctional nanocomposite that is slow-release and resistant to seawater corrosion and biofouling corrosion and to explore the synergistic effect between the two corrosion inhibitors. Design/methodology/approach: The morphology, structure and release properties of CAP@HNTs, BTA@HNTs and CAP/BTA@HNTs were investigated by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, specific surface area analysis and UV spectrophotometry. The corrosion resistance and antimicrobial properties were investigated by electrochemical measurements and bioinhibition rate tests, and the synergistic effect between the two corrosion inhibitors was explored by X-ray photoelectron spectroscopy. Findings: The CAP/BTA@HNTs are responsive to acidic environments and have significantly improved antibacterial and corrosion resistance compared with CAP@HNTs and BTA@HNTs. CAP and BTA have a positive synergistic effect on anticorrosion and antifouling. Originality/value: Two types of inhibitors, anticorrosion and antifouling, were loaded into the same nanocontainer to prepare a slow-releasable and multifunctional nanocomposite with higher resistance to seawater corrosion and biocorrosion and to explore the synergistic effect of CAP and BTA on corrosion resistance. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to reveal the effect of nano-Al2O3 particle addition on the nucleation/growth kinetics, microhardness, wear resistance and corrosion resistance of Co–P–xAl2O3 nanocomposite plating. Design/methodology/approach: The kinetics and properties of Co–P–xAl2O3 nanocomposite plating prepared by electroplating were investigated by electrochemical measurements, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Vickers microhardness measurement, SRV5 friction and wear tester and atomic force microscopy. Findings: A 12 g/L nano-Al2O3 addition in the plating solution can transform the nucleation/growth kinetics of the plating from the 3D progressive model to the 3D instantaneous model. The microhardness of the plating increased with the increase of nano-Al2O3 content in plating. The wear resistance of the plating did not adhere strictly to Archard's law. An even and denser corrosion product film was generated due to the finer grains, with a high corrosion resistance. Originality/value: The effect of different nano-Al2O3 addition on the nucleation/growth kinetics and properties of Co–P–xAl2O3 nanocomposite plating was investigated, and an anticorrosion mechanism of Co–P–xAl2O3 nanocomposite plating was proposed. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to improve the corrosion resistance of stainless-steel bipolar plate by magnetron sputtering. Design/methodology/approach: TiC/amorphous carbon composite film was deposited by magnetron sputter at four different temperature of 25°C, 200°C, 300°C and 400°C. The morphology, composition and structure of the film were characterized by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. And its corrosion behavior was analyzed through electrochemical impedance spectroscopy, potentiodynamic and potentiostatic polarization tests. Findings: A compact TiC/amorphous carbon film was prepared by magnetron sputtering on 316L stainless steel, and the particles of the film were refined with the increase in sputtering temperature. High temperature promoted the formation of TiC and C–C sp2 hybrid carbon, but excessively high temperature caused the oxidation of Ti and a significant decrease in sp2 hybrid carbon. The corrosion resistance of the film increased with the temperature, and the corrosion current density polarization at 0.86 V and 1.8 V for TiC/a–C film prepared at 400 °C is only 1.2% and 43.2% of stainless steel, respectively. Originality/value: The corrosion resistance of amorphous carbon films was improved by the doping of Ti carbide, and the appropriate sputtering temperature was obtained. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HA) bioactive film is a standard surface modification method for biodegradable Mg alloys. However, the corrosion resistance of HA film prepared before was mediocre, and the preparation process was complicated. In this study, hydroxyapatite film was prepared for the first time on layered double hydroxides (LDHs) coated Mg alloy by hydrothermal method. The structure and composition of LDHs and HA films were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The corrosion resistance and immersion behavior of the films in simulated body fluid (SBF) were investigated by using potentiodynamic polarization curve, electrochemical impedance spectroscopy (EIS) techniques. The effects of different pH and calcium to phosphorus molar ratios (Ca/P ratios) of HA hydrothermal solution were investigated. The experimental results show that HA films appear in petal-like, filamentous and flower-like. The corrosion resistance of the film first increases and then decreases with the pH from weak acid to alkaline. With the increase of the Ca/P ratio, the film is gradually denser, and the protective effect is enhanced. The immersion test results show that after 7 days of immersion, the impedance modulus of the composite film is about 5 × 103 Ω·cm2, which is ten times higher than the single LDHs film. The effects of the pH and Ca/P ratio of the HA hydrothermal solution on the preparation of HA film are simply explained by thermodynamic theory. The Mg-LDHs-HA composite film provide a corrosion protection barrier for Mg substrate and HA film is biologically active. The barrier effect and the mineralization behavior provide a better corrosion protection for Mg substrate. [Display omitted] • HA film was prepared for the first time on LDHs-coated Mg alloy. • The preparation method of the composite film is simple. • Mg-LDHs-HA composite film exhibits durable corrosion resistance in SBF solution. • The effects of pH and Ca/P ratio were explained using thermodynamic theory. [ABSTRACT FROM AUTHOR]

ZnO@ZIF-8 films were prepared on Q235 steel surface through solvothermal reaction by pre-electrodepositing ZnO films and modified with stearic acid (SA). The surface morphology, elements content, crystal structure and chemical structure of films were studied by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The wettability of films was measured by water contact angle meter. The corrosion behavior of films was tested by Electrochemical tests. ZnO films show hexagonal nanotubular morphology, having the best compactness and corrosion resistance at deposition current density of 2.3 mA/cm2 with the protection efficiency of 90.11%. After solvothermal reaction, ZIF-8 grains are formed and clad ZnO nanotubes, forming a contact film to prevent corrosive ions attacking steel efficiently. ZnO@ZIF-8 films have the best compactness and corrosion resistance at Zn2+ concentration of 0.06 mol/L with the protection efficiency of 99.83%. But the corrosion resistance of ZnO@ZIF-8 film declines quickly for the water molecules can get inside the film and destroy the bond between ZIF-8 grains. Thus, SA was grafted to ZnO@ZIF-8 film to enhance its hydrophobicity. After SA modification, the protection efficiency reaches 99.99% and maintains at 95.29% after 14 days immersion in the solution of 3.5 wt.% NaCl. [Display omitted] [ABSTRACT FROM AUTHOR]

A structure of {[(Co-DLC)/DLC] X } n Multilayered Nanocomposite Films (MNF) is designed by inserting pure DLC high-resistance layers into Co-DLC nanocomposite film, which consists of alternating Co-DLC and DLC layers were prepared by magnetron sputtering. The electrochemical behavior and magnetic property of the films are modulated by varying the number of deposition cycles (n) and the thickness of one single-cycle (X). The electrochemical results show that this MNF structure significantly improves the corrosion resistance of the films owing to the clear interfaces, which block the micropores penetrating the films. Compared to the co-sputtering film, as the number of cycles n increases to 7, the corrosion resistance is enhanced by one order of magnitude from 2.3 × 104 to 2.2 × 105 Ω·cm2. However, the interfaces between the Co-DLC and DLC layer become blurred when the thickness of one single-cycle X is lower than 30 nm, and the corrosion resistance decreases to 3.7 × 104 Ω·cm2. In terms of magnetism, the multilayer structure helps to regulate the homogeneity of Co particle size. As X increases from 30 to 100 nm, the Co particle size increases from 2.7 to 4.7 nm, and the saturation magnetization intensity (M s) of superparamagnetic property in the films increases from 2.8 to 8.2 mT. As X increases, the remanent magnetization ratio (M r / M s) decreases and reaches 0.011 at X = 100 nm, which is about one order of magnitude smaller than that of the co-sputtering film. This result indicates that the MNF have better superparamagnetic property. It is noteworthy that {[(Co-DLC)/DLC] X } n MNF with X ranging from 100 to 40 nm and n ranging from 3 to 7 can achieve high corrosion resistance and superparamagnetic property, simultaneously. • {[(Co-DLC)/DLC] X } n multilayered nanocomposite films (MNF) are constructed. • Micropores are blocked by multilayer interfaces to improve corrosion resistance. • High anticorrosion and superparamagnetic property are achieved, simultaneously. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnO resistive switching film is prepared by one-step hydrothermal method. • Application of electric field can promote the formation of oxygen-vacancy in film. • High-low resistive switching behavior of film varies with oxygen vacancy content. ZnO resistive switching films were prepared on the surface of SS304 using hydrothermal method combined with heat treatment. The surface and cross-sectional morphology, composition, oxygen vacancy content and semiconductor type of ZnO films were characterized. The corrosion resistance and resistance switching properties of ZnO films were determined by electrochemical methods. The oxygen vacancy formation energy, surface adsorption energy and diffusion barrier of ZnO system were calculated using first-principles. The results show that the samples with 0.5 mol/L Zn2+ and 4 mol/L NaOH have the best performance, and its corrosion resistance efficiency can reach more than 99.5 %. Calculations show that the ZnO film containing oxygen vacancies still prevents the entry of Cl−, and applied electric field promotes the formation of oxygen vacancies and conductive filaments. Thus, polarization-immersion treatment can adjust the oxygen vacancy content in film, which enables film to switch between high and low resistance states, realizing the cyclic resistance-switching performance of film and greatly extending service life. [ABSTRACT FROM AUTHOR]

Purpose: Nickel-aluminum bronze (NAB) has been widely used in ship propellers. It is always subjected to local micro-plastic deformation in service environments. This paper aims to study the influence of plastic deformation on the mechanical strength and corrosion resistance of NAB in 3.5 Wt.% NaCl solution. Design/methodology/approach: Scanning electron microscope and X-ray diffraction were used to analyze the microstructure of NAB alloy with different plastic deformations. Mechanical properties of the sample were measured by tensile experiment, and corrosion behavior was studied by electrochemical measurements and the long-term immersion corrosion test. Findings: Results showed that the plastic deformation caused lattice distortion but did not change the microstructure of NAB alloy. Microhardness and yield strength of NAB were significantly improved with the increase of deformation. The lattice distortion accelerated the formation of corrosion product film, which made the deformed alloy show a more positive open-circuit potential and an increased Rp. However, during the long-term immersion corrosion, the corrosion resistance of NAB alloys deteriorated with the increase of plastic deformation. This is because larger plastic deformation brought about higher internal stress in corrosion product film, which resulted in the premature peeling of the film and the loss of its protective effect on the alloy substrate. Originality/value: Tensile plastic deformations were found to cause a decline in the corrosion resistance of NAB. And the mechanism was clarified from the evolution of corrosion products during the corrosion process. [ABSTRACT FROM AUTHOR]

The Al2O3 powder was added as a filler to polyurea and the effect of doping amount on Shore hardness and wetting property were investigated. The electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion resistance of coating/aluminum alloy system in 0.1 mol/L NaOH solution. The results showed that with the increase of the doping amount, the Shore hardness of the coating increased and the contact angle on the aluminum alloy matrix decreased. By analyzing the results of the characteristics of EIS and the fitting results, doped Al2O3 powder can improve the coating corrosion resistance, but it may affect the density of the coating and reduce the impedance modulus during the initial stage of immersion. The relationship between the doping amount of Al2O3 powder and the corrosion resistance in this test was 5 wt % > 10 wt % > 15 wt % > 0 wt %. In general, in the doping range of this test, since the powder was uniformly distributed in the polyurea coating, the cohesive force of the polyurea can be lowered to cause an increase in the wetting property. At the same time, excessive dopped Al2O3 powder may deteriorate the compactness of the polyurea and the binding property of the polyurea itself may decrease, resulting in deterioration of corrosion resistance. However, the proper doping of Al2O3 powder in polyurea improves its overall performance. [ABSTRACT FROM AUTHOR]

• Cu-8-HQ@HNTs controlled the release of 8-HQ in response to acidic environment. • Cu-8-HQ@HNTs were distributed uniformly in epoxy and reduced the hydrophilicity of coating. • Cu-8-HQ@HNTs/epoxy coating provided long-term corrosion resistance. • Cu-8-HQ@HNTs/epoxy coating exhibited self-healing behavior under damage. 8-Hydroxyquinoline (8-HQ) corrosion inhibitor was loaded into halloysite nanotubes (HNTs) under negative pressure and encapsulated by Cu-8-HQ complex stopper, and then Cu-8-HQ@HNTs/epoxy coating was prepared by mixing Cu-8-HQ@HNTs with epoxy. The surface morphology, wettability and adhesion of coating were observed and determined by optical microscopy, sessile water droplet static contact angle and pull-off adhesion tester. The releasing behavior of 8-HQ in water was investigated by UV–vis spectrophotometer, and the corrosion resistance of epoxy coatings in 3.5% NaCl solution was analyzed by electrochemical impedance spectroscopy (EIS). Results show that the prepared Cu-8-HQ@HNTs complex has a higher release rate in acidic environment than that in neutral and alkaline solution. Cu-8-HQ@HNTs/epoxy coating has a smooth morphology, a higher and more stable corrosion resistance than that of blank epoxy coating and 8-HQ@HNTs/epoxy coating. The self-healing behavior of Cu-8-HQ@HNTs/epoxy coating is attributed by the dissolution of end stopper of HNTs due to the acidification of scratched coating edge zone and the release of 8-HQ from the HNTs. [ABSTRACT FROM AUTHOR]

Abstract To extend the applications of 316L stainless steel in corrosive environments and correlate the corrosion resistance with composition and microstructure, homogeneous Cr-rich layer with the thickness of 75 μm was fabricated on 316L stainless steel by pack chromizing and post heat treatment. The chromizing layer was mainly composed of Fe Cr solid solution. Post heat treatment eliminated the precipitates and Cr-depletion in the chromizing layer. The corrosion behaviors were studied by electrochemical measurements and corrosion morphology observation. The pitting corrosion in Cl− containing solutions was avoided after chromizing treatment, which was ascribed to the reduced sensitivity of Cr-rich surface to Cl− ions. The higher Cr concentration in the modified layer also improved the long-term stability of corrosion resistance. After immersion in NaCl solution for 24 days, the charge transfer resistance of chromizing sample was higher than that of 316L by a factor of 8.19. In addition, the free corrosion potential shifted to the positive direction after post heat treatment, and the corrosion current density was also reduced to 0.066 μA/cm2. The further improvement on anticorrosion performance was attributed to the homogeneous microstructure. Graphical abstract Unlabelled Image Highlights • The Cr-rich layer was fabricated by high-temperature pack chromizing treatment. • The chromizing layer provided enhanced pitting corrosion resistance for 316L SS. • The correlation between corrosion resistance and composition/microstructure was studied. • Post heat treatment homogenized the microstructure and further improved the performance. [ABSTRACT FROM AUTHOR]

• An sensor is designed to evaluate the shelf-life of tinplate cans. • Open circuit potential can be used as an indicator for corrosion resistance. • Potentiostatic step and EIS are fast methods for shelf-life assessment. • Shelf-life can be assessed by electrochemical equivalent circuit modeling. An electrochemical sensor is developed to evaluate the shelf life of lacquered tinplate cans by using open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiostatic step techniques. The voltage and current detection precision of measurement system are 0.25 mV and 500 pA. The evolution of OCP, coating resistance, charge transfer resistance, and current response after potentiostatic step can be used as indicators for shelf life evaluation. Through establishing the electrochemical equivalent circuits (EECs), the change of the corrosion resistance over time is formulated and its correlation with shelf life is elucidated. The results show that electrochemical methods are successfully applied in fast shelf-life assessment of metal packaging cans. [ABSTRACT FROM AUTHOR]

Abstract Zinc phosphate conversion coating was prepared on AZ61 magnesium alloy by using chemical conversion method, and then processed by hydrothermal treatment in solution containing Zn(NO 3) 2 and stearic acid. The surface morphologies, chemical characteristics and wettabilities of multilayer coatings were observed and characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), Fourier-transform infrared spectrophotometer (FTIR), Raman spectrometer and optical contact angle meter. The corrosion resistance of coatings were determined by polarization curves. Findings show that zinc phosphate conversion coatings on magnesium alloy are in block structure with microcracks and lower corrosion resistance. After hydrothermal treatment, there are few microcracks on the multilayer coating, and the dense ZnO and stearic absorbing layers are grown on conversion coatings with hydrophobic or even superhydrophobic character and higher corrosion resistance. With the increasing of Zn(NO 3) 2 concentration in hydrothermal solution, the water contact angle and corrosion resistance in 3.5 wt% NaCl solution of multilayer coatings are firstly increased and then decreased. The optimum Zn(NO 3) 2 concentration in hydrothermal solution is 0.035 mol/L, which the multilayer coating on magnesium alloy has the highest corrosion resistance with superhydrophobic properties. Based on experimental results, the protection mechanism of multilayer coating is discussed and related with the formation of dense ZnO layer and stearic absorbing layer on magnesium alloy. Highlights • Multilayer coating was fabricated by using phosphating and hydrothermal process. • Zn(NO 3) 2 concentration plays a significant role in the morphology and behavior. • Multilayer coating is composed by phosphating layer and ZnO layer. • Multilayer coating is hydrophobic/superhydrophobic by adsorbing of stearic acid. • Multilayer coating has a higher binding strength and corrosion resistance. [ABSTRACT FROM AUTHOR]

The nickel-ferric layered double hydroxides (NiFe-LDHs) film which are commonly used as catalysts was fabricated on Q235 steel in-situ via two-step hydrothermal method. And the superhydrophobic NiFe-LDH-PFDTES film was obtained by 1 H, 1 H, 2 H, 2 H-perfluorodecyltriethoxysilane (PFDTES) modification. To a certain extent, the application of NiFe-LDHs has been broadened. The structure and composition of NiFe-LDHs film and NiFe-LDH-PFDTES film were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), and Fourier transform infrared (FT-IR). The wettability of films was analyzed by water contact angle testing. And the corrosion resistance of NiFe-LDHs and NiFe-LDH-PFDTES film in 3.5 wt% NaCl solution were measured by using potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS) techniques. The results show that NiFe-LDHs and NiFe-LDH-PFDTES film were successfully prepared on the surface of Q235 steel. By adjusting the preparation conditions, the NiFe-LDH-PFDTES film with optimal corrosion resistance was prepared in the condition containing the hydrothermal solution concentration is 1 unit and hydrothermal time for 6 h. The hydrophobicity changes little with the hydrothermal parameters, and all reach the state of superhydrophobic, the contact angle is greater than 150°, the sliding angle is less than 1°. For the superhydrophobic film, NiFe-LDHs has excellent synergy with PFDTES, covering of an "air film" on the rough structure of LDHs, blocking the solution from contact with the substrate, thereby providing corrosion resistance. NiFe-LDH-PFDTES film exhibits much better corrosion protective performance than NiFe-LDHs film in 3.5 wt% NaCl solution, the impedance modulus is increased about 4–5 orders of magnitude compared with Q235 steel, and the highest protection efficiency can reach 99.99%. [Display omitted] [ABSTRACT FROM AUTHOR]

Microstructure evolution of the nickel-aluminum bronze alloy was studied by heat treatment, including annealing, normalizing, quenching and aging. The microstructure was refined and homogenized after quenching or quenching/aging at 450 ℃, which can eliminate selective phase corrosion effectively. Compared with the current production process, static corrosion rate reduced about 50%, due to the rapid formation of a protective film. In addition, cavitation corrosion rate reduced by a factor of 4.9 and 7.9 for the quenched and quenched/aged at 450 ℃ samples, respectively. This can be attributed to the improved hardness and weakened synergy between corrosion and mechanical attack. [ABSTRACT FROM AUTHOR]

The gradient Ni-Cu layer on nickel aluminum-bronze alloy was obtained by the thermal diffusion process. The corrosion resistance was improved due to the formation of protective film, consisted of Ni(OH) 2 and Cu 2 O. Although the Ni-Cu layer exhibited local corrosion with uniform corrosion and pitting corrosion simultaneously during the immersion test, the pitting growth was depressed because of the gradient distribution of Ni and Cu. The relieving driving force for galvanic corrosion between outer passive layer and bare Ni-Cu in the pitting was the main factor, which was caused by the decreasing interface potential drop. [ABSTRACT FROM AUTHOR]

As-cast nickel-aluminum bronze is prone to suffering selective phase corrosion in marine environments. To solve this problem, chromium was introduced via ion implantation to modify its surface microstructure, which was characterized by high-resolution transmission electron microscopy and auger electron spectroscopy. The corrosion behavior was studied by electrochemical measurements and salt spray test. It was found that the inherent selective phase corrosion in as-cast NAB was inhibited effectively when the implantation fluence was 5 × 10 17 ions/cm 2 . The improved corrosion resistance after ion implantation was believed to stem from the rapid formation of a more protective film containing chromium oxides and hydroxides. [ABSTRACT FROM AUTHOR]

[Display omitted] • Al x Zn 1- x O resistive switching film was successfully prepared on SS304 steel by sol–gel method. • Compared with substrate, Al x Zn 1- x O films have excellent corrosion resistance with lower corrosion current density and higher impedance value. • The film has excellent resistance switching performance. Regulating the concentration of oxygen vacancies in the film by the immersion-polarization process, the prepared film could be varied between the high resistance state and low resistance state, allowing the film to be recycled and thus extending its service life. Al x Zn 1- x O films were prepared on SS304 by using sol–gel method combined with spinning and heat treatment. The surface morphology, composition and structure of films were observed and characterized by scanning electron microscopy, X-ray diffractometer and Fourier transform infrared spectroscopy. The oxygen vacancy content and semiconductor type of Al x Zn 1- x O films were determined by X-ray photoelectron spectroscopy, electronic para -magnetic resonance spectroscopy, Mott-Schottky curve and density function theoretical calculation. The corrosion resistance and resistive switching performance of Al x Zn 1- x O films were measured by using electrochemical methods and immersion-polarisation experiments. The results show that the prepared Al x Zn 1- x O films are in n -type semiconductor material with a homogeneous and dense surface, the oxygen vacancy content is decreased with the increasing of Al dopping content. The corrosive resistance of Al x Zn 1- x O film was increased with the increasing of Al doping content with the best corrosion resistance at the doping content of 4% Al. During the immersion process, the corrosion resistance of Al x Zn 1- x O film was firstly increased and then decreased. The corrosion resistance of Al x Zn 1- x O films could be switched in the high and low resistance states under the immersion-polarization process by adjusting of the oxygen vacancy content in film. [ABSTRACT FROM AUTHOR]

Co-Diamond Like Carbon (Co-DLC) nanocomposite film is considered as a potential biosensor material owing to its various properties such as corrosion resistance and superparamagnetic property. In this work, by adjusting the substrate temperature from 298 to 673 K, the microstructure of Co-DLC nanocomposite film is modulated. With the rising of the substrate temperature, Co particle size increases from 3.8 to 6.4 nm and the crystallinity is improved; the sp2/sp3 ratio of the film is increased, which reduces micropores for penetration of corrosive entities. As a result, the saturation magnetization of superparamagnetic property is enhanced by 2.4 times from 0.11 to 0.26 T, and the total corrosion resistance of the film is enhanced by more than 300 times from 3.5 × 104 to 1.1 × 107 Ω·cm2. By establishing the mechanism model, the improvement of magnetic properties and corrosion resistance caused by microstructure controlling in Co-DLC nanocomposite film is reasonably explained. [Display omitted] • Large Co particle size and high crystallinity induced by high substrate temperature • Reduced micropores for corrosive entities penetration by increased sp2 clusters • 2.4-time superparamagnetic magnetization and 300-time corrosion resistance realized • High magnetic properties and corrosion resistance achieved simultaneously [ABSTRACT FROM AUTHOR]

[Display omitted] • Zn 1- x Cr x O resistive switching films were successfully prepared on the surface of SS304 by using the sol–gel method. • Compared with substrate, Zn 1- x Cr x O films have lower corrosion current density, higher impedance value, and excellent corrosion resistance. • The film has excellent resistance switching performance, and the oxygen vacancy concentration of the film can be adjusted by the immersion-polarization process to enable the prepared film to switch between high resistance and low resistance states, which greatly extends the service life of the film. Zn 1- x Cr x O resistive switching film with different Cr content was prepared on SS304 substrate by sol–gel method combined with spin plating and heat treatment. The surface morphology, composition, structure, semiconductor type and oxygen vacancy concentration of Zn 1- x Cr x O films were observed and analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Mott-Schottky curves, X-ray photoelectron spectroscopy (XPS) electron paramagnetic resonance spectroscopy (ESR) and density functional theory (DFT) calculation. And the corrosion resistance of Zn 1- x Cr x O film were investigated by polarization curves and electrochemical impedance spectroscopy (EIS). The results show that the prepared Zn 1- x Cr x O films have a uniform dense surface which belongs to n -type semiconductor type, and the oxygen vacancy concentration in the films increases with the increase of Cr content. With the increasing of Cr content, the corrosion resistance of films is decreased. During the immersion process, the corrosion resistance of Zn 1- x Cr x O film is firstly increased and then decreased with increasing immersion time. By applying immersion and polarization treatment the corrosion resistance of Zn 1- x Cr x O film could be regulated between the high and low resistance states (HRS and LRS) due to the creation and disappearance of oxygen vacancies in the film. [ABSTRACT FROM AUTHOR]

Nickel alloy 690 (Ni690) were fabricated by wire arc additive manufacturing (WAAM) with three kinds of TiC particles adding contents (no TiC addition, 0.5 wt% TiC, 1.0 wt% TiC) based on cold metal transfer (CMT) technology. The effects of TiC particles adding content on the microstructure, mechanical properties and corrosion resistance were investigated. After adding 1.0 wt% TiC particles, the average length of the γ grains decreased from 301 ± 61 µm to 114 ± 15 µm and the structure of grains changed from columnar dendrite into equiaxed dendritic at the top of each layer, which is results of the heterogeneous nucleation and increase of constitutional supercooling caused by TiC particles. The difference between horizontal and vertical mechanical properties of WAAM Ni690 component disappeared because the heterogeneous nucleation caused by TiC particles prevented the epitaxial growth. The ultimate tensile strength of the WAAM 1.0TiC-Ni690 component reached 590 MPa in both directions, which increased 10 % compared with no TiC addition. The improvement of mechanical properties was owing to the grain refinement and the formation of reinforcing TiC/(Ti, Nb)C second-phase particles. The potentiodynamic polarization tests showed that the improved corrosion resistance with the increased content of TiC particles. The electrochemical impedance spectroscopy (EIS) tests results showed that due to the refined γ columnar grains providing more nucleation sites, a denser and thicker passive film was formed, which improved the corrosion resistance. The composition of the passive film was analyzed by X-ray photoelectron spectroscopy (XPS). The results reflected the more content of oxides and hydroxides of Cr in the passive film of WAAM 1.0TiC-Ni690 sample represented the denser passive film and better corrosion resistance. • Nickel alloy 690 (Ni690) were fabricated by wire arc additive manufacturing (WAAM) with different kinds of TiC particles adding contents. The TiC particles improved the mechanical properties and corrosion resistance • With the addition of TiC particles, the anisotropy in strength of WAAM Ni690 component disappeared for heterogeneous nucleation and the reinforcing TiC/(Ti, Nb)C particles improved the strength of WAAM 1.0TiC-Ni690 component in both directions reaching 590 MPa. • The refiner columnar γ grains offered more nucleation sites on the grain boundaries for the formation of thicker passive film. The more content of oxides and hydroxides of Cr in the passive film of WAAM 1.0TiC-Ni690 component represented the denser passive film and better corrosion resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A NIR-induced self-healing MIL-53@TA/PCL coating was designed and prepared by using MIL-53@TA as photothermal agent and PCL as low-melting-point layer. • The MIL-53@TA/PCL composite coating possesses excellent photothermal property. • The MIL-53@TA/PCL composite coating greatly improves corrosion resistance of Mg alloy. • The scratched MIL-53@TA/PCL coating can be healed within 10 min irradiated by 808 nm NIR (0.17 W/cm2) A novel self-healing composite coating was fabricated on magnesium alloy by using polycaprolactone (PCL) as resin matrix and iron-based metal-organic framework MIL-53 modified with tannic acid (TA) as function filler. The surface morphology, structure and wettability of composite coating were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and sessile water droplet static contact angle. The corrosion resistance and healing performance of PCL coatings was determined by electrochemical impedance spectroscopy (EIS) and photothermal tests. Results indicate that MIL-53@TA/PCL coating possesses a flatter surface, a higher corrosion resistance and better photothermal effect than that of blank PCL coating and MIL-53/PCL coating. Under the near-infrared (NIR) laser irradiation with the wave length of 808 nm, the scratched MIL-53@TA/PCL coating could be healed within 10 min because of the excellent photothermal conversion ability of MIL-53@TA component. [ABSTRACT FROM AUTHOR]

Various strategies have been developed to fabricate mechanical robust superhydrophobic membranes on the original substrates. However, for superhydrophobic coatings that have to be homologous to the inherently fragile substrate, their mechanical stability problems have not been satisfactorily solved. Herein, we prepared three hierarchical superhydrophobic Cu coating via facile pulse electrodeposition with microstructure size of 10–15, 30–40, and 60–70 µm, respectively. The resulting superhydrophobic coatings simultaneously exhibit excellent self-cleaning, mechanical robustness, and corrosion resistance. A hydrophobic mechanism suitable for worn superhydrophobic surfaces was proposed, which can well analyze the influence of microstructure changes on wettability. Moreover, these three coatings can withstand 15, 50, and 100 cycles of sandpaper abrasion, respectively, as the size of the microstructure increases. The results demonstrate a size effect of microstructure, which means surfaces with larger-sized microstructures can better maintain their superhydrophobicity under mechanical damage. Our findings offer a reference for improving the mechanical robustness of other superhydrophobic coatings that are homologous to the substrate. [Display omitted] • Three superhydrophobic Cu coatings with mechanical robustness, self-cleaning, and corrosion resistance were fabricated. • A hydrophobic mechanism suitable for worn superhydrophobic surfaces was proposed. • The size effect of microstructure on resisting mechanical damage was investigated. • A strategy in improving the mechanical stability of fragile coatings homologous to the substrate was found. [ABSTRACT FROM AUTHOR]

[Display omitted] • A superhydrophobic hierarchical Cu cone-flower structure was fabricated. • Correlation of roughness skewness and void volume ratio to wettability was studied. • A new hydrophobic model was proposed to explain effect of structural parameters. Superhydrophobic films have been successfully prepared on various substrates by finely controlling surface micro/nanostructure's roughness and reducing surface energy. However, there is no unified conclusion about the correlation of surface roughness and 3D volume parameters to wettability. Herein, we fabricated a superhydrophobic film composed of hierarchical Cu cone-flowers via facile one-step pulse electrodeposition with a 30% duty cycle for 20 min. Based on this film, the relationship between roughness/volume parameters and hydrophobicity was well studied. The resulting cone-flower film exhibits excellent corrosion resistance and self-cleaning properties due to a high water contact angle (WCA) of ~160° and a low sliding angle (SA) of ~3°. The large roughness skewness (Rsk = 0.7–1.3) and void volume ratio (Vvc/Vmc > 1.5) are shown to be more desirable to achieve superhydrophobic surfaces. Moreover, a new hydrophobic model is proposed to explain the above results, which means that the nanoscale air cushions share most of the gravity of water droplets to help microscale air cushions closer to the Cassie state. Further experiments by adding or destroying the nanostructures to observe the change of hydrophobicity well verified our conjecture. [ABSTRACT FROM AUTHOR]

• Pure Zn and Zn-epoxy powder coatings was prepared by zincate electrodeposition. • The addition of epoxy powder improves microstructures and reduce roughness. • The incorporation of epoxy powder enhances the corrosion resistance. • The incorporation of epoxy powder hinders the hydrogen permeation. • The addition of epoxy powder improves the wear resistance. To improve the corrosion and wear resistance of the coating and reduce the effect of hydrogen penetration on the performance of galvanized steel, Zinc-epoxy powder (EP) composite coatings were prepared by alkaline zincate electrodeposition. The results show that the Zn-6 g/L EP coating has the lowest root mean square roughness of 281.99 A. The incorporation of EP enhances the corrosion resistance of the coating. The Zn-6 g/L EP coating has the largest coating resistance and charge transfer resistance. The incorporation of EP can hinder the hydrogen permeation, which may reduce the hydrogen embrittlement of galvanized steel. Tribological experiment shows that the wear resistance of the composite coating is improved. The friction coefficient and wear scar width of the Zn-12 g/L EP coating is the lowest. [ABSTRACT FROM AUTHOR]

To realize the potential application of the Co-DLC magnetic nanocomposite film in biosensor, it is necessary to obtain superparamagnetic property with high magnetization and good corrosion resistance in Co-DLC film. However, the cobalt carbide produced in the traditional preparation process will deteriorate the superparamagnetic property of Co-DLC film. To suppress the formation of cobalt carbide, strong magnetic target co-sputtering has been induced to prepare the Co-DLC nanocomposite films in this work. The results show that the cobalt particles are distributed in the amorphous DLC matrix. Most of cobalt exists in the form of metallic cobalt, and no cobalt carbide is formed during the film deposition process. The films maintain superparamagnetic property, which fits well with the Langevin equation. The saturation magnetization of the Co-DLC films increases with the increase of cobalt content, which reaches 0.068 T at cobalt content of 36 at. %. Meanwhile, when the cobalt content increases, the degree of graphitization of the film increases, which leads to a decrease in corrosion resistance of the film. Whereas, the polarization resistance of Co-DLC nanocomposite film is still higher than 1.03 × 105 Ω·cm2. The Co-DLC nanocomposite films with cobalt content between 29 and 36 at. % exhibit superparamagnetic property with high saturation magnetization and corrosion resistance. [Display omitted] • The method of strong magnetic target co-sputtering inhibits the formation of cobalt carbides in Co-DLC films successfully. • These films maintain superparamagnetic property, which is fitted well with Langevin equation. • The corrosion resistance of the Co-DLC film is above 10 times higher than that of the cobalt film. • The films with cobalt content between 29 and 36 at. % exhibit both high saturation magnetization and corrosion resistance. [ABSTRACT FROM AUTHOR]

Cu-MBT@HNTs/epoxy self-healing coating was fabricated by using epoxy resin and Cu-MBT@HNTs nanocomposite inhibitor, which composed by halloysite nanotubes (HNTs) with containing 2-mercaptobenzothiazole (MBT) and Cu-MBT encapsulated end stopper. The surface morphology, static contact angle and adhesion force of Cu-MBT@HNTs/epoxy coating were observed and detemined by optical microscopy, static contact angle and pull-off adhesion tester, and the release behavior of MBT from Cu-MBT@HNTs was determined by UV–Vis spectrophotometer. The corrosion and self-healing behavior of Cu-MBT@HNTs/epoxy coating in 3.5% NaCl solution was evaluated by electrochemical impedance spectroscopy (EIS) technique. The experimental results show that MBT is successfully loaded into HNTs with a loading capacity of 12.3(wt.) %, and the formation of Cu-MBT end stopper could reduce the release rate of MBT in water especially in the acidic and neutral water. The prepared Cu-MBT@HNTs/epoxy coating has a smoother morphology, larger static contact angle and higher adhesion force than that of MBT@HNTs/epoxy coating. With the addition of Cu-MBT@HNTs, the scratched Cu-MBT@HNTs/epoxy coating has a higher polarization resistance and a better self-healing performance than that of blank epoxy coating and MBT@HNTs/epoxy coating, which resulted from the release of MBT inhibitor from HNTs by the local alkaline condition and the formation of Fe-MBT inhibition film on the scratched area of steel substrate. Unlabelled Image • Cu-MBT@HNTs controlled the release of MBT in response to alkaline environment. • Cu-MBT@HNTs were distributed uniformly in epoxy and reduced the hydrophilicity of coating. • C u -MBT@HNT s /epoxy coating exhibited self-healing behavior under damage. [ABSTRACT FROM AUTHOR]

• DL-EPR was used to describe the precipitation of carbides in super Cr13 stainless steel. • The main reason for the decrease in impact toughness is the precipitation of continuous Cr-rich carbides (M23C6) along the interface. • Solution treatment before quenching and tempering treatment can improve the impact toughness. • The impact tough of the steel can be predicted by DL-EPR. Super martensitic stainless steel (SMSS) is characterized by improved mechanical properties and corrosion resistance. However, during production the impact toughness will be significantly reduced under certain heat treatment regimes (tempering at 873 K followed by quenching at 1213 K and tempering at 913 K). Double loop electrochemical potentiokinetic reactivation (DL-EPR) were used to investigate the mechanism for the reduction of impact toughness in this experiment. It was found that the primary cause for the decrease was precipitation of continuously distributed Cr-rich carbides (M 23 C 6) along martensite lath boundaries. The Ra value obtained by DL-EPR is positively correlated with the amount of Cr-rich carbide precipitation. As Ra increases, impact toughness increases first and then decreases rapidly, which indicates that it is reasonable to use Ra to qualitatively predict the impact toughness of the steel. [ABSTRACT FROM AUTHOR]

• PASP-Zn films were constructed on Q235 steel by coordination self-assembly. • PASP-Zn films can improve the corrosion resistance of Q235 steel significantly. • Corrosion resistance is related to PASP/Zn ratio, pH value and assembly time. • The assembly and protection mechanism of PASP-Zn films are proposed. In this work, an economical and environmentally friendly polyaspartic acid-zinc (PASP-Zn) film was successfully prepared on the surface of Q235 steel by coordination self-assembly, and the preparation conditions of PASP-Zn film were optimized by single factor method. The surface morphology and thickness of PASP-Zn film were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the structure and composition of PASP-Zn film were determined by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The corrosion resistance of PASP-Zn film on Q235 steel in 3.5wt % NaCl solution was analyzed by electrochemical impedance spectroscopy (EIS) and polarization curves. The results show that PASP film and PASP-Zn film are successfully prepared on the surface of Q235 steel, and the single PASP film is self-assembled monolayers with thin thickness and loose structure. Whereas PASP-Zn film shows a rough morphology, accompanied by appearance of a large amount of nanoparticles, and the thickness of PASP-Zn film is about 98.0 nm. PASP-Zn film exhibits much better corrosion protective performance than PASP film in 3.5 wt % NaCl solution, and the highest protection efficiency can reach 94.48 %. The excellent coordination ability between PASP and zinc ions can effectively improve the compactness and thickness of PASP-Zn film, and prevent the corrosive ions from contacting the Q235 steel surface. By adjusting the preparation conditions, a PASP-Zn film with optimal corrosion resistance was prepared in the film-forming solution containing PASP/Zn ratio of 1:8 and pH value of 5.0 for 30 min. [ABSTRACT FROM AUTHOR]

A supersaturated solid solution layer with a fine-grained size of 30–50 μm was formed on a nickel–aluminum bronze via laser surface quenching technology, and its corrosion resistance was improved by 42.6%, which was attributed to the homogenized element distribution and the formation of a more protective film during corrosion process. • The microstructure of as-cast NiAl bronze was refined by laser surface quenching. • Selective phase corrosion was eliminated for the uniform element redistribution. • Corrosion rate decreased 42.6% after laser surface quenching. • Enhanced corrosion resistance was ascribed to formation of a more protective film. Laser surface quenching technology was utilized to modify the surface microstructure of as-cast nickel-aluminum bronze. A supersaturated solid solution layer with a fine-grained size of 30–50 μm was formed, and its corrosion behavior was studied by electrochemical measurements and long-term immersion corrosion test. It was found that laser surface quenching homogenized the distribution of elements in the constituent phases and eliminated the selective phase corrosion. Due to the formation of a more protective film on laser quenched NAB alloy, the corrosion rate reduced about 42.6% compared with that of as-cast NAB alloy. [ABSTRACT FROM AUTHOR]

• Cavitation erosion behaviours of surface chromizing layer were investigated. • The pitting and galvanic corrosion resistances were enhanced due to high Cr concentration. • Excellent combination of surface hardness and surface toughness was obtained. • The cavitation erosion mechanism of chromizing layer was proposed. To enhance the cavitation erosion resistance of industrial components, two types of Cr-rich diffusion layers were fabricated on 316L stainless steel through pack chromizing process. The chromizing layer before post heat treatments exhibited poor cavitation erosion performances, which could be ascribed to its high brittleness and the galvanic corrosion. The chromizing layer after post heat treatments showed the excellent cavitation erosion resistance with a 3.97 times lower erosion mass loss compared with that of 316L stainless steel. The corrosion resistance was significantly improved with a 12.5-time lower free corrosion current density than 316L stainless steel, and the surface mechanical properties of chromizing layer also exhibited great combination of hardness and toughness. Therefore, the higher cavitation resistance was attributed to the better corrosion and mechanical performances originating from the more homogeneous microstructure after post heat treatments. [ABSTRACT FROM AUTHOR]