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Mg alloys are considered the most promising engineering materials because of their unique properties. However, the uncontrolled corrosion rate of these alloys limits their applications. Therefore, in this study, a micro-arc oxidation layer was used as a transition layer to “directly” grow a zinc-based metal-organic framework (MOF) composite coating on the surface of a Mg alloy (AZ91D). Herein, the two zeolitic imidazolate framework (ZIF-8) coatings with different morphologies were separately prepared by homologous metal oxide induction and a one-step in-situ growth method. The superhydrophobic composite coating showed strong hydrophobicity and self-cleaning properties, which could prevent the penetration of water and corrosive ions (Cl−) into the surface of AZ91D. Electrochemical tests demonstrated that the super-hydrophobic composite coatings greatly enhanced the corrosion resistance of AZ91D, and the corrosion current density decreased from 10−5 to 10−9 A/cm2. These results indicate that the ZIF-8 coatings are beneficial for improving the hydrophobicity and enhancing the corrosion resistance of Mg alloys. Therefore, MOF composite coatings provide a new strategy that can be used to prepare multifunctional anticorrosion coatings on metal substrates.

Formation of super-hydrophobic and corrosion-resistant coatings can provide significant corrosion protection to magnesium alloys. However, it remains a grand challenge to produce such coatings for magnesium-lithium alloys due to their high chemical reactivity. Herein, a one-step hydrothermal processing was developed using a stearic-acid-based precursor medium, which enables the hydrothermal conversion and the formation of low surface energy materials concurrently to produce the super-hydrophobic and corrosion-resistant coating. The multiscale microstructures with nanoscale stacks and microscale spheres on the surface, as well as the through-thickness stearates, lead to the super-hydrophobicity and excellent corrosion resistance of the obtained coating.

Recently, functional molecules such as Polydopamine (PDA), Hyaluronic Acid (HA) and heparin have been widely studied in the field of surface modification of magnesium (Mg) alloy stents for better degradation behavior and biocompatibility, but their further application is limited by undesirable anticoagulant function, uncontrollable degradation and easy bleeding, respectively. Regarding to this consideration, a magnesium Fluoride/Polydopamine/Sulphonated hyaluronic acid (MgF2/PDA/S-HA) composite coating was successfully prepared by applying S-HA with sulfur content of 9.71 wt% on the surface of ZE21B alloy in this study. The results showed that the composite coating with a unique mesh structure not only inherited the anticoagulant effect of sulfonic acid group and the excellent cyto-compatibility of S-HA with high sulfur content, but also significantly improved the corrosion performance of ZE21B alloy. These results indicate a great application potential of the composite coating in the field of cardiovascular biomaterials.

The rapid degradation of magnesium (Mg)-based implants in physiological environment limits its clinical applications, and alloying treatment is an effective way to regulate the degradation rate of Mg-based materials. In the present study, three Mg alloys, including Mg-0.8Ca (denoted as ZQ), Mg-0.8Ca-5Zn-1.5Ag (denoted as ZQ71) and Mg-0.8Ca-5Zn-2.5Ag (denoted as ZQ63), were fabricated by alloying with calcium (Ca), zinc (Zn) and silver (Ag). The results obtained from electrochemical corrosion tests and in vitro degradation evaluation demonstrated that the three Mg alloys exhibited distinct corrosion resistance, and ZQ71 exhibited the lowest degradation rate in vitro among them. After addition of Zn and Ag, the antibacterial potential of Mg alloys was also enhanced. The in vitro cell experiments showed that all the three Mg alloys had good biocompatibility. After implantation in a rat femoral defect, ZQ71 showed significantly higher osteogenic activity and bone substitution rate than ZQ63 and ZQ, due to its higher corrosion resistance as well as the stimulatory effects of the released metallic ions. In addition, the average daily degradation rate of each Mg alloy in vivo was significantly higher than that in vitro, as could be due to the implantation site located in the highly vascularized trabecular region. Importantly, the correlations between the in vitro and in vivo degradation parameters of the Mg alloys were systematically analyzed to find out the potential predictors of the in vivo degradation performance of the materials. The current work not only evaluated the clinical potential of the three biodegradable Mg alloys as bone grafts but also provided a feasible approach for predicting the in vivo degradation behavior of biodegradable materials.

Superhydrophobic coating has been widely studied for its great applicational potential, such as for corrosion protection of magnesium alloys while it has been restrained by expensive materials, sophisticated preparation process and infirm rough structures. In this study, the electrochemical method was adopted by using a two-electrode system for rapid hydrophobic modification to obtain superhydrophobic kaolin. By mixing the modified superhydrophobic kaolin with commercial epoxy resin and polydimethylsiloxane glue, a paint can be formed and easily used on various substrates for preparation of superhydrophobic coating via spraying method. The influence factors on wettability of the modified kaolin and the mixing ratio of each component of the coating were explored. Also, the wettability, durability and anticorrosion of the prepared coating were evaluated comprehensively. The coating was able to maintain superhydrophobic after immersed in HCl solution at pH 1, the NaOH solution at pH 14, and 3.5 wt.% NaCl solution for 16, 21, 30 days, respectively. In addition, the coating exhibited 4A grade adhesion, high hydrophobicity after abraded for 200 cycles on a 600-mesh sandpaper with 100 g weight, and 99.86% anticorrosion efficiency after soaked in 3.5 wt.% NaCl solution for 20 days, demonstrating a good robustness and anti-corrosion property. Furthermore, the coating showed good transparency, flexibility and was easy to make in a large scale by the spraying method, which is of great significance to promote the practical application of superhydrophobic coatings and the anticorrosion Mg alloys.

Corrosion behavior of AZ31 magnesium alloy in NH4+-bearing chloride solution with controlled pH was investigated by weight loss experiment, hydrogen collection, and electrochemical test combined with surface morphology and topography observation. The results show that NH4+ and pH of the solution can affect the corrosion of AZ31 magnesium alloy. The existence of NH4+ affects the formation and dissolution of corrosion products, which makes the protective effect of the corrosion product layer weaker. The change of pH value not only affects the corrosion mechanism of AZ31, but also alters the concentration of NH4+ ions in the solution, which further influences the corrosion product layer of AZ31, and finally makes the corrosion of AZ31 change significantly.

In this study, themicrostructure and corrosion properties of Vermicular Graphite Cast Iron (VGCI)produced via different methods and parameters were investigated. VGCI wasproduced from a base ductile iron material using different proportions ofvermiculariser and inoculant. Copper was added to a group of samples as analloying element. The microstructures and corrosion properties of samples wereinvestigated in saltwater media. The effects of production parameters on themicrostructure and corrosion behavior were determined. It was observed that asthe ratio of vermiculariser applied was increased, the vermicular graphiteratio and vermicularity was also increased. The matrix grain size decreased whilethe inoculant and pearlite phase ratio increased due to the addition of copper.In electrochemical corrosion studies, VGCI was superior in corrosion resistancecompared to SGCI and addition of vermiculariser, inoculants and copper wasfound effective in improving the corrosion resistance of the VGCI material.

Objectives Magnesium alloys are the potential candidate for metallic implants due to their excellent mechanical characteristics, biodegradable nature, and properties similar to human bone. However, a high degradation rate is primary obstacle in implementing these alloys as biodegradable orthopedic implants. Powder-mixed electric discharge machining (PMEDM) is an emerging method of surface modification of metallic alloys that can be implemented to improve the corrosion resistance of Mg alloys. Therefore, PMEDM using zirconium (Zr) and manganese (Mn) powder particles has been proposed to modify the surface characteristics of Mg-4Zn alloy. Materials and Methods In the present work, Zr and Mn powders have been used in varying concentrations during PMEDM of Mg-4Zn alloy. Experiments were conducted as per mixed design L18 orthogonal array (OA). Taguchi and Grey Relational Analysis (GRA) have been used to optimize the process parameters. Analysis of response characteristics, namely material removal rate (MRR), surface roughness (SR), and thickness of the alloyed layer (TAL), has been carried out at different values of input variables (like powder additives (Pa), powder concentration (Cp), peak current (Ip), pulse on time (Ton) and duty cycle (DC)). The corrosion analysis was carried out by immersing the specimen (machined at an optimized setting) in simulated body fluid (SBF). Results It is observed from the analysis that Cp, Ip, and Ton play a pivotal role in evaluating response characteristics. The favorable setting suggested by the gray approach is Pa: Zr; Cp: 2 g/l; Ip: 4A; Ton: 50 μs; DC: 80%, while responses at this setting are confirmed by confirmation experiments with MRR: 32.14 mm3/min; SR: 5.578 μm and TAL: 8.28 μm. The immersion test signifies that the corrosion rate (CR) of PMEDMed sample (3.20 mm/year) is 40.74% lesser than the corrosion rate of polished sample (5.40 mm/year). Conclusion Zr powder shows better performance in terms of higher MRR, lower SR and higher TAL as compared to Mn powder during the PMEDM process. The corroded surface of polished sample exhibited larger size micro pits and cracks than the machined sample, which concluded that surface modification of MZ-4Zn alloy via PMEDM is a powerful tool to enhance its corrosion resistance.

Epoxy resin powder coating has been successfully applied on the corrosion protection of magnesium lithium alloys. However, poor wear resistance and microcracks formed during the solidification have limited it extensive application. There are limited approaches to exploit such anti-corrosion and mechanical properties of magnesium lithium alloys. Herein, the epoxy resin powder coating with polydopamine modified molybdenum disulfide (MoS2@PDA-EP powder coating with 0, 0.1, 0.2, 0.5, 1.0 wt.% loading) was well prepared by melt extrusion to investigate its anticorrosion performance and wear resistance. The results revealed that the addition of MoS2@PDA enhanced the adhesion strength between coatings and alloys, wear resistance and corrosion protection of the powder coatings. Among them, the optimum was obtained by 0.2 wt.% MoS2@PDA-EP powder coating which could be attributed to well dispersion and efficient adhesion with coating matrix. To conclude, MoS2@PDA-EP powder coating is meaningfully beneficial for the anticorrosive and wear performance improvement of magnesium lithium alloys.

Electrochemical splitting of seawater is highly preferable over freshwater electrolysis to produce sustainable hydrogen terrifically due to its abundance in nature. Seawater electrolysis is encouraging to produce green hydrogen and safe drinking water. The accomplishment of seawater electrolysis needs robust and cost-effective anode material that should acquire an excellent catalytic activity, durability, and selectivity for OER and have high resistance against Cl- corrosion. Here we report a free-standing anode consisting of partially amorphous sulfur substituted copper oxide (S-Cu2O-CuO) nanoneedles directly grow on Cu foil. Benefiting from high electrical conductivity, plentiful active sites, high intrinsic activity per active site, and fast rate for ionic and electronic transfer, these disorders nanoneedles structured S-Cu2O-CuO demonstrate outstanding OER performance needing an overpotential of 450 mV to attain a high geometric activity (1000 mA cm−2) in 1 M KOH. Its disordered surface structure and amorphous features lead to improved corrosion resistance and durability, making it a prospective anode for direct seawater electrolysis. It requires an overpotential of 420 mV to achieve a geometric activity of 500 mA cm−2 in alkaline seawater and sustain water electrolysis for 100 h without making hypochlorite. Because of the facile, scalable, and economical approach, the catalyst is highly promising for large-scale realistic alkaline seawater electrolysis.

The uncontrolled growth of lithium dendrites and accumulation of “dead lithium” upon cycling are among the main obstacles that hinder the widespread application of lithium metal anodes. Herein, an ionic liquid (IL) consisting of 1-methyl-1-propylpiperidinium cation (Pp13+) and bis(fluorosulfonyl)imide anion (FSI−), was chosen as the additive in propylene carbonate (PC)-based liquid electrolytes to circumvent the shortcoming of lithium metal anodes. The optimal 1% Pp13FSI acts as the role of electrostatic shielding, lithiophobic effect and participating in the formation of solid electrolyte interface (SEI) layer with enhanced properties. The in-situ optical microscopy records that the addition of IL can effectively inhibit the growth of lithium dendrites and the corrosion of lithium anode. This study delivers an effective modification to optimize electrolytes for stable lithium metal batteries.

The superlattice La-Y-Ni-based hydrogen storage alloys have high discharge capacity and are easy to prepare. However, there is still a gap in commercial applications because of the severe corrosion of the alloy in electrolyte and poor high-rate dischargeability (HRD). Therefore, (LaSmY)(NiMnAl)3.5 alloy was prepared by magnetic levitation induction melting, and then the alloy was coated with different contents (0.1 wt%–1.0 wt%) of nano-carbons by low-temperature sintering with sucrose as the carbon source in this work. The results show that the cyclic stability and HRD of the alloy first increase and then decrease with the increase of carbon contents. The kinetic results show that the electrocatalytic activity and conductivity of the alloy electrodes can be enhanced by carbon coating. The electrochemical properties of the alloy are the best when the carbon coating content is 0.3 wt%. Compared with the uncoated alloy, the maximum discharge capacity (Cmax) improves from 354.5 to 359.0 mAh/g, the capacity retention rate after 300 cycles (S300) enhances from 73.15% to 80.01%, and the HRD1200 of the alloy enhances from 74.39% to 74.39%.

Aqueous zinc energy storage devices, holding various merits such as high specific capacity and low costs, have attracted extensive attention in recent years. Nevertheless, Zn metal anodes still suffer from a short lifespan and low Coulombic efficiency due to corrosion and side reactions in aqueous electrolytes. In this paper, we construct an artificial Sn inorganic layer on Zn metal anode through a facile strategy of atoms exchange. The Sn layer suppresses Zn dendrite growth by facilitating homogeneous Zn plating and stripping during charge and discharge processes. Meanwhile, the Sn protective layer also serves as a physical barrier to decrease Zn corrosion and hydrogen generation. As a result, The Sn-coated anode (Sn|Zn) exhibits a low polarization voltage (∼34 mV at 0.5 mAh/cm2) after 800 testing hours and displays a smooth and an even surface without corrosion. Moreover, the zinc ion capacitor (Sn|Zn|| activated carbon) is assembled with an enhanced capacity of 42 mAh/g and a capacity retention of 95% after 10000 cycles at 5 A/g. This work demonstrates a feasible approach for the commercialization of aqueous Zn-based energy storage devices.

DC deep-well grounding electrode (DWGE) has become a new type of grounding configuration due to its small area requirement. However, gas produced by DWGE during electrolysis may causes more severe exhaust problem than conventional electrode. To investigate the influence of different electrode materials on DWGEs gas evolution, an innovative U-shaped experimental platform was proposed to collect cathode and anode gases separately. The metalelectrolyte contact interface in a DWGE project was simulated to perform gas evolution experiments on three typical grounding electrode material. The gas evolution speeds of the materials when used as the cathode and anode were obtained. The polarization curves were used to analyze the order of corrosion speeds, and the effect of the materials on the order of the gas evolution speed. The results revealed that when operated as an anode, MMO and high silicon cast iron produce oxygen, whereas carbon steel does not. Furthermore, the evolution of O2 in MMO is faster than that in high silicon cast iron. When operated as cathode, the three materials generate hydrogen, and carbon steel exhibits the slowest H2 evolution speed. The current from the power supply consist of the reaction current of metal corrosion and gas generation.

In the context of a joint research project, a system for monitoring, protection and strengthening of bridges by using a textile reinforced concrete interlayer has been developed; the system consists of two carbon layers with a spacing of 15 mm and a special mortar. This setup led to the idea of building up an electrical field between the carbon meshes, to suppress the ingress of chlorides into the concrete. This paper focuses on the question of which voltages and electrical field strengths are necessary to prevent critical chloride contents at the reinforcing steel. For this purpose, extensive laboratory tests have been performed, followed by a numerical simulation study. By applying an electrical field, the negatively charged chloride ions are forced to move to the upper carbon mesh, which is polarised as an anode. It has been investigated whether the voltages to implement an electrochemical chloride barrier are smaller than they have to be for the common preventive cathodic protection. One advantage of this chloride barrier is that, because of the lower current densities, the anodic polarisation of the carbon meshes can be reduced. Therefore, different voltages, electrical field strengths, anode materials and anode arrangements were investigated.

The cerium conversion coating (CeCC) containing copper and manganese cations was applied to the galvanized steel. The microstructure and the composition of specimen were analyzed by field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). Electrochemical impedance spectroscopy (EIS) and polarization tests were conducted in 3.5 wt% NaCl solution to investigate the coating corrosion resistance. The results show that there are improvements in corrosion resistance and microstructure of CeCC containing copper and manganese cations but copper ions increase corrosion resistance of CeCC from 5800 to 27000 Ω⋅cm2.

Nichel-Phosphorus (Ni-P) coatings are deposited on mild steel by using an electroless plating process. The effect of three calix[4]arene derivatives, namely tetra methyl ester-P-tertbutyl calix[4]arene (Calix1), tetra acid-P-tertbutyl calix[4]arene (Calix2) and tetra methyl P-tert-butyl-thicalix[4]arene ester (Calix3) on the deposition rate, the deposit composition, and the morphological surface was investigated and the study of growth mechanisms has delivered useful information about the surface properties of deposit. It is found that these additives modify the deposition rate and the nickel crystallization process. In fact, the Calix1 and Calix3 act as an accelerator, while Calix2 acts as an inhibitor for the nickel electroless. Furthermore, it is shown that the chemical bath is more stable with calix[4]arene derivatives addition and the obtained deposits are compact and adherent. It is observed also that the nickel content increases with additives. On the other hand, the X-ray diffraction showed that the orientation peaks are intensified at {111} in the presence of Calix2, confirming obtained results of EDAX spectrum. The cyclic voltammetry revealed that the tested additives strongly influence the cathodic process and slightly affect the hypophosphite oxidation. Finally, it is found that these compounds improve the anticorrosion efficiency of Ni-P coating on the mild steel substrate in 3%(mass) NaCl, where its polarization resistance increases with Calix2 and Calix3 addition.

The corrosion and weaker interaction with metal catalysts of common carbon supports during electrocatalysis push the development of alternative supports materials. Titanium oxide-based materials have been widely explored as electrocatalysts supports in consideration of their chemical stability, strong interactions with metal catalyst and wider applications in electrocatalytic reactions as well as the improved electronic conductivity. This review summarizes recent research advances in engineering titanium oxide-based supports for the catalysts in electrocatalysis field to provide guidance for designing high performance non-carbon supported electrocatalysts. Typically, the titanium oxide-based supports are classified into shaped TiO2, doped TiO2, titanium suboxide and TiO2-carbon composites according to the modification methods and corresponding preparation methods. Then the engineering strategies and electrocatalytic applications are discussed in detail. Finally, the challenges, future research directions and perspectives of titanium oxide-based supports for electrocatalysis are presented for practical applications.

Microbiologically influenced corrosion (MIC) is an unavoidable problem in several industries. Copper (Cu) and its alloys are widely used engineering materials. However, MIC of Cu remains a persistent challenge to their performance and functional lifetime under aggressive environments. This study investigated nanosecond pulsed laser processing (LP), which may enhance the corrosion resistance of Cu. The microstructural evolution and corrosion behavior of LP-Cu in the presence of sulfate-reducing bacteria (SRB) were evaluated. Typical deformation-induced microstructural features of high-density dislocations were analyzed on the top surface of LP-Cu coupon. Electrochemical measurements suggested that LP-Cu coupons exhibited better corrosion resistance in SRB-inoculated solution compared with their original counterpart. The enhanced corrosion resistance by LP primarily resulted from the combined influences of compressive residual stress and work hardening in the surface. However, overlap percentage played a key role in improving corrosion resistance. LP produced optimal corrosion resistance at 50% overlap. Therefore, this study introduces a unique and an option for anticorrosion control in manufacturing processes and potentially implements it onto other materials to improve its microbial corrosion resistance through LP.

Magnesium (Mg) alloys can be regarded as the most promising biodegradable implant materials for orthopedic and stent applications due to their good biocompatibility and low Young's modulus which is near to that of natural bone. However, its applicability is hindered because it exhibits a high corrosion rate in the physiological environments. In this work, we fabricated Mg66Zn30Ca4/Fe bulk metallic glass composites via spark plasma sintering (SPS). We studied the influence of different contents of Fe on the properties of the composites. The results indicated that Fe was uniformly distributed on the surface of Mg66Zn30Ca4 metallic glass (MG) as a second phase, which led to an improvement in the corrosion resistance and mechanical strength. The standard potential of Mg66Zn30Ca4/Fe bulk metallic glass (BMG) composites increased as compared to Mg66Zn30Ca4, while their mechanical strength improved from 355 MPa to 616 MPa. Furthermore, cytotoxicity was investigated via the CCK-8 assay and calcein-AM staining, which revealed that the extraction mediums diluted 6 times (EM × 6) of the Mg66Zn30Ca4 and Mg66Zn30Ca4/Fe did not cause cell toxicity on day 3 and 5, while the EM × 6 of the Mg66Zn30Ca4 showed cytotoxicity on day 1, 3 and 5. Thus, Mg66Zn30Ca4/Fe BMG composites exhibit significant potential for fabricating implants with good mechanical strength and corrosion resistance.

International audience; Yttrium mono- and di-silicates are excellent candidate materials for Environmental Barrier Coatings (EBC), to protect Ceramic-Matrix Composites (CMC). A large distribution of microstructures can be generated by varying the duration of sintering, the particle size distribution of the precursor and/or the deposition method. In the present work, investigations of the corrosion resistance of yttrium silicate coatings with various microstructures in the high temperature range, under different oxidizing environments are reported. An original experimental methodology has allowed quantifying the influence of the microstructure (especially grain size and grain boundary surface area) on properties such as ionic conductivity, resistance to oxygen diffusion, volatilization rate and surface recession, and showing that they directly affect their protection efficiency against oxidation. Based on these results, guidelines for the design of an optimized yttrium silicate EBC featuring microstructural and compositional variations are proposed.

In recent years, pure iron (Fe) has attracted significant attention as a promising biodegradable orthopedic implant material due to its excellent mechanical and biological properties. However, in physiological conditions, Fe has an extremely slow degradation rate with localized and irregular degradation, which is problematic for practical applications. In this study, we developed a novel combination of a nanostructured surface topography and galvanic reaction to achieve uniform and accelerated degradation of an Fe implant. The target-ion induced plasma sputtering (TIPS) technique was applied on the Fe implant to introduce biologically compatible and electrochemically noble tantalum (Ta) onto its surface and develop surface nano-galvanic couples. Electrochemical tests revealed that the uniformly distributed nano-galvanic corrosion cells of the TIPS-treated sample (nano Ta–Fe) led to relatively uniform and accelerated surface degradation compared to that of bare Fe. Furthermore, the mechanical properties of nano Ta–Fe remained almost constant during a long-term in vitro immersion test (~40 weeks). Biocompatibility was also assessed on surfaces of bare Fe and nano Ta–Fe using in vitro osteoblast responses through direct and indirect contact assays and an in vivo rabbit femur medullary cavity implantation model. The results revealed that nano Ta–Fe not only enhanced cell adhesion and spreading on its surface, but also exhibited no signs of cellular or tissue toxicity. These results demonstrate the immense potential of Ta-implanted surface nanostructures as an effective solution for the practical application of Fe-based orthopedic implants, ensuring long-term biosafety and clinical efficacy., Graphical abstract Image 1, Highlights • The degradation rate of nanostructured Fe implants was accelerated by TIPS technique. • Ta ions were accelerated strongly toward the Fe surface by TIPS process. • Nano Ta–Fe showed long-term mechanical stability and accelerated degradation rate. • Nanostructured Ta–Fe surface showed enhanced in vitro and in vivo cellular responses. • Ta-implanted Fe is a promising material for biodegradable orthopedic implants.

For this study, NiCrBSi–TiN composite coatings were fabricated on Q235 steel substrates by reactive plasma spraying and the coatings were heat treated at 600 °C, 700 °C, 750 °C and 800 °C for 1 hour. The microstructure evolution of these coatings untreated and treated at different temperatures was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The hardness of the coatings was characterised using the Weibull distribution while the wear and corrosion resistance were studied using a block-ring tribometer and an electrochemical workstation. The phase composition of coatings after heat treatment changed, the compactness of coatings was increased, and the interlayer bonding was significantly improved. Comprehensive experimental results illustrated that the performance of the NiCrBSi–TiN composite coatings was excellent at the heat treatment temperature of 700 °C.

The safety and cycle lifespan of zinc metal-based aqueous batteries are greatly restricted by zinc anode. The poor cycling performance of zinc metal anode is often considered to be impacted by the dendrite growth, surface passivation, zinc metal corrosion and hydrogen evolution reaction, while surface roughness is a matter that has often been ignored in past studies. Herein, a roughness gradient is constructed on the zinc anode surface by a simple grinding and pasting method. It has been found the modified zinc anodes with lower surface roughness exhibit the smaller zinc deposition overpotential and longer cycle life. Further, in situ optical microscopy photographs indicate that the zinc anode with an optimized roughness enables more uniform distribution of zinc precipitation and corrosion sites, which will facilitate a stable cycling performance of aqueous zinc ion batteries. The Zn anode dendrite-suppressing mechanism via surface roughness engineering was revealed through finite element computational simulation. These results emphasize the effectiveness of roughness engineering for tuning the surface physics of Zn anode and provide a facile strategy to develop better and safer aqueous zinc ion batteries.

Selective and efficient electrochemical analytical methods for the characterization of the corrosion behavior of beryllium bronze alloys are significant and necessary. These electrochemical methods are based on open-circuit chronopotentiometry curves, potentiodynamic polarization, and electrochemical impedance spectroscopy. From the electrochemical analysis, the results show that the corrosion reaction of the untreated samples became more severe as the NaCl concentration was increased. However, the corrosion reaction was not obvious when the alloy was treated by commercial latex paint and laboratory-produced latex paint. Furthermore, the corrosion potential has same variation tendencies and the value of the corrosion potential was more positive when the alloy surface was treated by the laboratory-produced latex paint. The maximum and minimum of the corrosion potential were found for conditions using the untreated samples and samples treated with the laboratory-produced latex paint. The corrosion c...

C/C–SiC composites have enormous potential as a new generation of brake materials. It is worth studying the friction and wear behaviours of these materials in special environments to ensure the safe and effective braking of trains in practical applications. In this study, the braking behaviours and wear mechanisms of C/C–SiC mating with iron/copper-based PM in dry, wet and salt fog conditions are compared in detail. The results show that the coefficient of friction (COF) in the wet condition is reduced by 14.13% compared with that under the dry condition. The COF value of the first braking under salt fog condition is increased by 12.27% and 30.75% compared to the dry and wet conditions, respectively. Additionally, the tail warping phenomenon of the braking curve disappears in wet condition, which is attributed to the weak adhesion of friction interfaces and the lubrication of the water film. The main wear mechanisms of C/C–SiC mating with iron/copper-based PM under dry condition are adhesive, fatigue and oxidation wear. However, the dominant wear in wet condition is abrasive wear. The cooling and lubrication of water reduce the tendency of thermal stress, and weaken adhesive and fatigue wear. Furthermore, salt fog can accelerate the corrosion of alloy friction film, leading to the damage of friction film. Meanwhile, the third body particles formed in salt fog condition participate in the braking process. The wear mechanisms in salt fog condition are dominated by abrasive and delamination wear.

Defect-engineering in transition-metal-doped carbon-based catalyst plays an essential role for improving the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance. Herein, we report a ball-milling induced defect assisted with ZnCl2 strategy for fabricating defect-rich iron/nitrogen co-doped graphene-based materials (Fe-N-G). The substantial mechanical shear forces and the constant corrosion to the carbon matrix by ZnCl2 lead to the creation of abundant defects in graphene-based materials, which facilitates doping for heteroatoms. The defect-rich Fe-N-G catalyst with abundant Fe-Nx active sites displays excellent ORR performance. For OER, the over potential for Fe-N-G outperforms that of RuO2 in 1 M KOH at 10 mA cm−2. The Density Functional Theory calculations unravel that the impressive OER performance is attributable to the introduction of abundant defects. Additionally, the liquid and all-solid-state zinc-air batteries equipped with the prepared material as the air cathode demonstrate high power density, high specific capacity, and long charge–discharge stability. This work offers a practical method for manufacturing high-performance electrocatalysts for environmental and energy-related fields.

Applications of superhydrophobic (SHS) and lubricant infused surfaces (LIS) involve exposure to corrosive environments from the acidic to the basic, at a range of temperatures, that are not fully characterized. We present for the first time a multifactorial study of the effects of surface fabrication method, surface modification, surface functionalization time, temperature and pH of the immersion medium on the corrosion performance of nonwetting copper surfaces. Bioinspired SHS and LIS fabricated using facile methods of etching and electrodeposition are systematically assessed using potentiodynamic polarization measurements for their corrosion resistance in saline solution ( pH ≈ 7) over a temperature range 23–85 °C. SHS and LIS are shown to exhibit diminished corrosion rate, by up to two orders of magnitude, compared to bare copper surface. An Arrhenius model is developed for the first time, describing the temperature-dependent corrosion rate of SHS and LIS. Electrochemical impedance spectroscopy is used to show that corrosion resistance of LIS is larger by three orders of magnitude in extremely acidic ( pH = 1) and by an order magnitude in extremely alkaline ( pH = 14) media compared to bare copper surface. Etched LIS are generally more resistant to corrosion compared to SHS at all temperatures with excellent microstructural durability.

The lead tab serves as a terminal that collects charges generated from each electrode inside the battery and transfers it to the outside of the battery. Among the lead tabs used in the electric vehicle industry, a corrosion of aluminum (Al), chromium-coated Al (CCAl), copper (Cu), and nickel-coated Cu(NCCu) during the cycling of lithium-ion batteries is investigated. Cyclic voltammetry (CV) analysis are performed as part of the electrochemical corrosion test during battery cycle life, scanning electron microscope (SEM) for checking lead tab surface, and X-ray photoelectron spectroscopy (XPS) depth profile for a chemical analysis. By the CV results, it was inferred that the Cr and Ni coatings form a layer on the surface, and the morphology was visually confirmed by post CV SEM analysis. Subsequent XPS results confirm the sub-reaction related to LiPF6-carbonate electrolyte. Finally, the composition and distribution of the formed passivation layer were finally confirmed by XPS depth profile analysis. These passivation layers prevent the corrosion of the lead tab and contribute to the extension of battery life by inhibiting the dissolution of Al and Cu metals and the decomposition of the electrolyte during the charge/discharge test of LIB.

Owing to the corrosive sulphides in the mineral insulating oil such as dibenzyl disulphide (DBDS), copper windings in oil‐immersed transformers may suffer sulphur corrosion. This study investigates the influence of different contact conditions on the corrosion of copper conductors in transformers. Oil‐immersed accelerated corrosion experiment was conducted on copper conductors with various contact materials and different layers of insulating paper. The surface micromorphology, deposition component and the potentiodynamic polarization characteristics of copper conductors were explored. The results show that copper with different contact materials suffer sulphur corrosion; conversely, bare copper rarely does. It was also verified that the existence of a particular gap between copper and contact layer is a significant factor in sulphur corrosion by the formation of a concentration cell on the copper surface. The insulating paper wrapped around copper conductors does not increase the corrosion tendency of copper; however, it contributes to the formation of a region concentrated with DBDS, Cu2+, H+ by adsorption and impediment, which plays a key role in facilitating the sulphur corrosion of copper conductors. Moreover, sulphur corrosion can also occur on other metal parts in transformers when there is a particular gap on surfaces other than copper.

A one-step hydrothermal treatment was used to deposit a nano silver-loaded magnesium-aluminum hydrotalcite (Ag/Mg-Al) layered double hydroxide (LDH) coating onto the surface of a Mg-Zn-Ca alloy to improve the corrosion resistance and antibacterial properties of magnesium alloys for biomedical applications. The effect of experimental parameters such as temperature and time on the microstructure, compositions, and corrosion resistance of the Ag/LDH coating during the hydrothermal treatment was investigated to optimize the preparation process. Additionally, the in vitro degradation performance, antibacterial performance and biocompatibility of the coating were evaluated to determine the optimal preparation condition. The results show that when the LDH–NO3– coating is prepared at 110 °C for 10 h, the constituting silver particles (dimensions, 10–30 nm) are obtained, while the corrosion current density and the corrosion rate decrease to 4.41 μA/cm2 and 0.27 mm/year, respectively. The antibacterial experiment demonstrates that the coating effectively inhibits the reproduction of Escherichia coli while offering remarkable biocompatibility.

Rare earth passivation was conducted on Zn coated NdFeB magnets by chemical reaction to enhance the corrosion resistance performance. Morphologies, microstructures and compositions of different passivated coatings were studied by X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy, respectively. The corrosion behavior was evaluated by electrochemical measurement and neutral salt spray test. The results show that the rare earth passivation can enhance the corrosion resistance of Zn coated NdFeB magnets. When the concentration of cerium nitrate is 5 g/L, the passivated specimens can achieve the longest NSS time of 360 h, which is 144 h longer than that of the pristine Zn/NdFeB magnets. The passivation layer on the Zn coating surface contributes to the enhancement of the magnets’ corrosion resistance.

Refractory high-entropy alloy nanocomposites (HEA-NPs) are important class of materials with unique structure and potential applications. Although several synthetic methods have been reported, developing novel routes to prepare nanoscale HEA-based catalysts facilely is still urgently desired. This work takes advantage of confinement assisted arc and plasma shock (APS) to prepare a series of HEA-NPs by regulating the type and proportion of metal precursors. The phase constitutes and morphology of the HEA-NPs are fully characterized. The prepared refractory HEA-NPs possesses five highly dispersed metal components, including titanium (Ti), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo) and simultaneously exhibits an uniform hexagonal morphology of nanocrystals. By taking advantage of its unique corrosion resistance, TiNbTaCrMo HEA-NPs can function as a promising candidate for electrocatalytic hydrogen evolution reaction (HER) in natural seawater. And its catalytic performance after alloying is significantly enhanced compared with the elemental metal. Theoretically, the promoted HER activity can be attributed to the strong adsorption for the various metal components in HEA-NPs caused by the upshifting d-band center close to the Fermi level. Furthermore, this confinement strategy can be further extended to synthesize other HEA-NPs. Our strategy provides a novel method to synthesize various HEA-NPs for further catalytic application.

Magnesium (Mg) has emerged as one of the third-generation biomaterials for regeneration and support of functional bone tissue. Mg is a better choice over permanent implants such as titanium, stainless steel, cobalt-chrome as magnesium is biodegradable and does not require a second surgery for its removal after bone tissue recovery. It also reduces the risk of stress shielding as its elastic modulus is closer to human bone in comparison to permanent implants and other biodegradable metallic implants based on Iron and Zinc. Most importantly, Mg is osteoconductive thus stimulates new bone formation and possess anti-bacterial properties hence reducing the risk of failure due to infection. Despite its advantages, a major concern with pure Mg is its rapid bio-corrosion in presence of body fluids due to which the mechanical integrity of the implant deteriorates before healing of the tissue is complete. Mechanical properties of Mg-based implants can be enhanced by mechanical processing, alloying, and topology optimization. To reduce the corrosion/degradation rate, Mg has been alloyed with metals, reinforced with ceramics, and surface coatings have been applied so that the degradation rate of Mg-based implant matches with that of healing rate of bone tissue. The present review discusses the effect of alloying elements and reinforcing ceramics on microstructure, mechanical, and corrosion properties of Mg-based orthopedic implants. In addition, the biocompatibility of Mg-based alloys, composites, and coatings applied on Mg implants has been highlighted. Further, different methods of fabricating porous implants have been highlighted as making the implant porous facilitates the growth of new bone tissue through the pores.

The microporous magnesia aggregates show a promising application prospect as tundish lining, due to the excellent thermal insulation. In this study, the effect of nano-sized Al2O3 addition on the corrosion resistance of microporous magnesia aggregates against tundish slag is explored. The results show that the addition of nano-sized Al2O3 deteriorates the slag resistance of microporous magnesia aggregates, which is mainly because that the apparent porosity of aggregates increases with the addition of nano-sized Al2O3. Furthermore, MgO·Al2O3 spinel is formed in situ at the grain boundaries of Al2O3-bearing aggregates and the dissolution of MgO·Al2O3 spinel into molten slag damages the structure of aggregates. For the Al2O3-free microporous magnesia aggregates, as expected, the penetration of high basicity slag (CaO/SiO2 = 9, mass ratio) into refractory is slighter than that of low basicity slag (CaO/SiO2 = 4, mass ratio). But, for the Al2O3-bearing microporous magnesia aggregates, the corrosion of refractory by high basicity slag is severer. This is mainly because that MgO·Al2O3 spinel is more unstable in high basicity slag. Therefore, it is not suitable to add nano-sized Al2O3 for the preparation of microporous magnesia as tundish lining.

This study aims to investigate the corrosion of a SiC-coated graphite susceptor using NH3 and Cl2 in an epitaxial growth environment. The corrosion performance of NH3 with graphite and SiC-coated graphite was investigated through microstructure characterization and mass loss rate changes in detail. Gaseous NH3 had a high corrosion rate on the graphite substrate, but hardly reacted with the SiC coating. Additionally, analyses of the tested samples revealed that Cl2 gas corroded the SiC coating at high temperatures and formed many corrosion holes and residual free carbon on the surface. As the Cl2 concentration increased, the corrosion depth gradually increased. Further experiments on commercial SiC-coated graphite susceptors showed that Cl2 preferentially corroded the grain boundaries of the SiC coating, and then the grains were corroded, resulting in a decrease in the coating strength until cracking and failure.

For the mass production of astatine-211, a promising radiopharmaceutical for cancer treatment, the National Institute for Quantum and Radiological Science and Technology has proposed the innovative “Liquid Bismuth Target System.” The target window in this system must be made from a material that resists the highly corrosive liquid bismuth environment. To meet this requirement, a promising target window material was selected in corrosion experiments performed in stagnant liquid bismuth. Based on knowledge of corrosion in liquid lead–bismuth eutectic gained during the development of fast reactors and accelerator-driven subcritical systems, FeCrMo–alloy, FeCrAl–alloy, and austenitic stainless steel (as a reference) were selected as the specimen materials. Experiments were carried out under saturated dissolved oxygen and low oxygen conditions, and the corrosion behaviors of the specimens were evaluated, mainly by scanning electron microscopy. The FeCrAl–alloy exhibited the most excellent corrosion resistance, followed by FeCrMo–alloy. Both materials are suitable candidates for the target window. Although austenitic stainless steel was less corrosion resistant than the former two materials, it is a likely applicable for the target window under appropriately limited operation conditions (such as irradiation current and exposure time) of the liquid bismuth target system.

This study used aluminum powder as a raw material to fabricate a wick for loop heat pipes by the powder metallurgy method and took advantage of the excellent corrosion resistance, low density and low cost of aluminum. The average pore diameter, porosity and permeability of the aluminum wicks were 9 ?m, 47.65%, and 2.1 ? 10?13 m?2, respectively. Then, to verify the feasibility of the aluminum wick, it was installed into a loop heat pipe to test the heat transfer performance. The experimental results showed that the loop heat pipe could transport a heating load of 130 W with a thermal resistance of 0.04 K/W under horizontal condition. A steady-state loop heat pipe mathematical model was developed, and the numerical results were compared with the experimental data. The results show that the model data are consistent with the experimental data, which means that Al wicks are suitable for use in the case of a high heating load and light weight.

Owing to the unique properties of ZnO nanoparticles attracted the attention of researchers to work in fluid heating and cooling industries. These particles have fine thermal conductivity (TC), resistive to corrosion, antibacterial behavior, less costly and ease in availability. ZnO based nanofluids were also used in various heat transfer applications. In this article, different characterization techniques of ZnO nanopowder have been studied. These techniques are Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Analysis of X-rays (EDAX), X-ray diffraction (XRD) and RAMAN spectroscopy. FESEM was used to find topographical surface details with morphological behaviour of examined nanoparticles. Detailed FESEM images were shown at different magnifications of measurement. EDAX gave the elemental analysis and proof of purity of sample. XRD depicted the information about crystallographic planes of mentioned nanoparticles through Miller indices. Good chemical and structural properties of ZnO nanoparticles were found through different studied characterization techniques. Thus, ZnO nanoparticles based nanofluids were also considered as potential candidate in various thermo-fludic industries.

Corrosion of magnesium (Mg) is generally manifested by cathodic hydrogen gas evolution and concomitant anodic Mg dissolution. The surface condition significantly modified the corrosion of Mg, especially related to the deformation. The corrosion behaviour of AZ31 Mg alloy with emphasis on surface condition effect has been investigated. Filiform-like corrosion was observed significantly along the grinding path due to surface modification by mechanical grinding. From the cross-section characterization, the corrosion attack into the crystallographic structure. The analysis of corrosion behaviour is based on the polarization behaviour during the electrochemical measurement and scanning vibration electrode technique (SVET) measurement for local electrochemical quantification. Cathodic filiform body with Mg(OH)2 formation promoted the anodic corrosion propagation. Thick non-protective corrosion product formed after a longer immersion period was associated with uniform pitting propagation tunneled underneath the alloy, confirming the autocatalytic cathodic activation.

Nowadays, there is heavy demand for the present materials of different grades due to their important properties like high impact strength, high hardness, corrosion resistance, high tensile and compressive strength, etc. These properties make these materials rely on them for most of the application. These fiber laminates are very good material for automobile and aerospace applications, especially for automobiles used for car bumpers due to their high impact strength. One of the most important matters in making this laminate is its adhesive bonding between fiber glass and aluminium. Here in this study, both glass fiber and glass fiber reinforced with aluminium are manufactured. Various mechanical tests like tensile, compressive, and impact tests are carried out based on the ASTM standards, and the strength of these laminates is observed for the applied load. It is concluded that the impact, tensile, and compression strength of glass fiber reinforced with aluminium is greater than that of only glass fiber laminate. It will result in more dynamic and fusible properties in the composite structure. Thus the strength of glass fiber with Al is higher than that of only glass fiber laminate.

In this paper, the effect of rare earth oxide additive on coating material deposited by laser cladding process on various engineering materials has been discussed. The purpose of rare earth oxide additive in the coating composition is to improve the various properties like mechanical, tribological, and chemical properties. The main rare earth oxides are La2O3, CeO2 and Y2O3, which are generally used in laser cladded coatings. The limited amount of addition of these rare earth oxide compound may leads to improvement in hardness, wear and corrosion resistance of coating. The attractive properties of rare earth oxide is grain refinement, conversion of coarse structure to fine dendritic structure, creating grain boundary movement hindrance of dislocation in the material which leads to its application as nutrients in the coating material. The main purpose of coating is to enhance the surface properties of material like hardness, corrosion resistance and wear resistance. When rare earth oxide are added to the coating then it creates extra enhancement in the above properties. The laser cladding is widely used in modern manufacturing technology due to its very attractive properties like good metallurgical bonding with substrate, less dilution, minimum distortion, less heat affected zone and fast solidification and high cooling rate. In this review article the coating developed by laser cladding on various conventional engineering materials like ferrous materials, magnesium alloys, titanium alloys, aluminium alloys and nickel based super alloys with rare earth oxide addition are described.

Featured with high power density, improved safety and low-cost, rechargeable aqueous zinc-ion batteries (ZIBs) have been revived as possible candidates for sustainable energy storage systems in recent years. However, the challenges inherent in zinc (Zn) anode, namely dendrite formation and interfacial parasitic reactions, have greatly impeded their practical application. Whereas the critical issue of dendrite formation has attracted widespread concern, the parasitic reactions of Zn anodes with mildly acidic electrolytes have received very little attentions. Considering that the low Zn reversibility that stems from interfacial parasitic reactions is the major obstacle to the commercialization of ZIBs, thorough understanding of these side reactions and the development of correlative inhibition strategies are significant. Therefore, in this review, the brief fundamentals of corrosion and hydrogen evolution reactions at Zn surface is presented. In addition, recent advances and research efforts addressing detrimental side reactions are reviewed from the perspective of electrode design, electrode–electrolyte interfacial engineering and electrolyte modification. To facilitate the future researches on this aspect, perspectives and suggestions for relevant investigations are provided lastly.

Selective laser melting (SLM) is an additive manufacturing process in which layers of metallic powder are selectively melted and fused by a high-powered laser to form near-fully dense 3D components. The SS316L is an austenitic chromium-nickel stainless steel containing a deliberate amount of molybdenum which increases general corrosion resistance and especially improves its pitting resistance to chloride ion solutions. The importance of process parameter such as layer thickness and orientation of specimen on the hardness and microstructure are being explored. Hence, it is essential to carry out research in that direction. The aim of the study is to understand the effect of layer thickness and angle orientation on hardness of the material as it is one of the desirable properties for SS316 material. The excellent hardness (218.835 BHN) was attained at the angle orientation of 90° and layer thickness of 40 µm according to ANOVA analysis.

Bentonite is low resistance water retaining conductive clayey material often used as grounding enhancement material, particularly in a troubled environment. Due to its unique property, bentonite retains water and dissipate unwanted electrical current to ground. However, bentonite's water retention capacity would inevitably induce corrosion to the grounding electrode and may jeopardize the grounding system's performance in the long run. This study presents bentonite properties on copper electrodes' corrosion behavior. In this study, copper corrosion behavior buried in Andrassy bentonite specimens was investigated under varying relative humidity conditions using the vapor equilibrium technique. The corrosion rate was calculated at equilibrium, and FESEM later characterized the corroded surfaces. The copper corrosion rate in Andrassy bentonite was found to be between 2.2 and 2.8 × 10-3 mm/year. Test results showed that more water might not necessarily induce and expedite copper corrosion. However, it was noted that copper corrosion was somewhat limited under extremely dry conditions and very wet conditions. On the other hand, RH = 75% was the optimum copper corrosion condition to occur. It is believed that the corrosion of copper specimen may be influenced by other complex mechanism presence of such as chemicals species and microbes contained within the bentonite and surrounding environment.

Hexagonal boron nitride (h-BN) fillers are incorporated into poly(vinyl butyral) (PVB) coatings to improve the corrosion protection performance of copper. It has been revealed that the h-BN fillers exhibit an excellent dispersiblility in PVB coating due to the non-covalent interactions between h-BN fillers and the PVB molecules. Electrochemical characterization reveals that the corrosion resistance of the BN-reinforced PVB (BN-P) coating is 5–6 orders of magnitude higher than that of the pristine PVB coating. Photographs and metallography show that the copper substrate beneath the BN-P coating does not suffer from corrosion after immersion for 2 months, indicating that the BN-P coating can provide a long-term protective barrier for the underlying copper substrate. Loading 0~0.25 g h-BN fillers in 2.0 g PVB, the corrosion protection performance increases with increasing the loading of h-BN fillers. The scratch test results suggest that h-BN fillers do not accelerate copper corrosion when the BN-P coating is damaged.

Iron corrosion is a subject of great technological importance and extensive public concern. However, the highly efficient detection of iron corrosion at early stage is still a challenging task. Herein, bright fluorescent carbon dots (CDs) with superior response to Fe3+ were prepared by simple solvothermal process based on citric acid and ammonia. The obtained CDs are able to rapidly, sensitively and selectively respond to Fe3+. The quantitative analysis showed that the CDs exhibited a linear response to Fe3+ in the range of 10 to 300 µM, with a detection limit of 0.9 μM. And the fluorescence quenching of CDs was obvious enough to be detected by the naked eyes. Such promising responsiveness of CDs offers a great opportunity for real-time and visual detection of Fe3+ during electrochemical corrosion process. In addition, due to the excellent stability and solubility of CDs, patterned papers and hydrogels have been fabricated utilizing cellulose and PVA as matrices. The as-prepared biocompatible, environmental-friendly and disposable CDs based fluorescent materials were successfully used for detecting the degree of iron corrosion. This could provide a simple and visual strategy for monitoring the safety of structural metal materials.

Magnesium (Mg), a trace element in the human body, has excellent properties for use as a biodegradable medical implant. Metallic materials such as stainless steel, Co-based alloys, Ti alloys etc. used in biomedical implants. The use of corrodible alloying metals for medical applications has recently been increased. Magnesium as a biodegradable alloy has stupendous properties like elastic modulus, mechanical properties, good biocompatibility, very close to bone properties and helps in bone remodelling or ossification. The review study focuses on the degradation behavior of Mg-based alloys, influenced by alloying elements to increase resistance to corrosion, mechanical properties and bioactivity. This study reveals that the degradation rate can be controlled by lowering the corrosion rate through proper alloying by elements such as Zr, Sr, Mn, Ca, Zn, Al and rare earth elements and enhanced biocompatibility. The analysis has been discussed for cardiovascular, orthopaedic, tissue engineering, and therapeutic implant applications focused on Mg-based alloys.