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Dendritic growth is a common behavior during the electrodeposition of zinc, which degrades the compactness and thickness uniformity of the zinc film. In this work, a series of quaternary ammonium compounds (QAC) with different non-polar groups (based on the number of carbon atoms in non-polar groups represented as C1, C4, C8, C12 and C16, respectively) were introduced into the basic electrolyte to inhibit the zinc dendritic growth. The results showed that the deposition of zinc became smoother with the increase of non-polar group length, which was attributed to the fact that the non-polar groups of the additive limit the random diffusion of Zn2+ and changed the adsorption state of the surface, so that a uniform zinc film was obtained. Meanwhile, the Zn-Zn symmetric cells with the addition of C8 achieved a stable cycle time of over 600 h. But with the further increase of length (C12 and C16), the migration of Zn2+ to the electrode surface became extremely difficult for strong steric hindrance, resulting in a rough deposition morphology. • The non-polar groups of the selected additives have a hindering effect on zinc ions. • Regulating the hydrocarbon chain length of the nonpolar group of the additive change the zinc film morphology. • The additive with appropriate hydrocarbon chain length obtain uniform zinc deposition. [ABSTRACT FROM AUTHOR]

Modulating the morphology of metal-organic frameworks (MOFs) has been identified as an effective strategy for enhancing the electrocatalytic performance of CO 2 reduction reactions (CO 2 RR). In this study, CAU-17 MOFs ([Bi(BTC)(H 2 O)]·2 H 2 O·MeOH) were prepared via a sonication-assisted method at room temperature, which is considered a simpler technique compared to the conventional hydrothermal method. Additionally, the morphology of CAU-17 MOFs was further regulated by incorporating a rare-earth metal (La), resulting in the observation of two distinct structures, i.e. CAU-17 hexagonal prism (CAU-17-HP) and CAU-17 layer (CAU-17-Layer). Compared to CAU-17-HP, CAU-17-Layer exhibits an excellent selectivity towards formate with the maximum Faradaic efficiency of 95.5% at − 1.1 V RHE in an H-cell. Subsequently, the limited catalytic activity of CAU-17-Layer was boosted by anchoring nano CeO 2 onto its surfaces (CeO 2 @CAU-17-Layer). The as-prepared composite catalyst demonstrated outstanding performance in the conversion of CO 2 to formate, with a current density surpassing − 100 mA cm-2 at potentials more negative than − 1.0 V RHE and reaching − 200 mA cm-2 at − 1.5 V RHE in a flow cell. This study demonstrates the significant potential of morphology-engineered and rare-earth metals composited MOFs in facilitating highly efficient reduction of CO 2. • Bismuth-based metal-organic frameworks (CAU-17 MOFs) were prepared via a sonication-assisted method at room temperature. • The morphology of CAU-17 MOFs was regulated by rare-earth metal (La). • Morphology engineering boosted the catalytic performance of CAU-17-MOFs. • When incorporating nano-CeO 2 into CAU-17-Layer, the current density reached − 200 mA cm-2 at − 1.5 V RHE. [ABSTRACT FROM AUTHOR]

The preparation of copper matrix composites with high graphene content is difficult, facing the problem of graphene agglomeration. This study proposed a layer-by-layer electrodeposition method to obtain the reduced graphene oxide/copper (RGO/Cu) composite with a layered structure. It was found that the layered distribution of RGO avoided the occurrence of agglomeration effectively, which was conducive to the excellent mechanical strength and toughness of the composite. The strength of the RGO/Cu composite increased with the number of layers, and the tensile strength of the 29-layer composite was 34.2 % higher than that of pure copper. While, its elongation remained at the same level as that of pure copper. The toughening and strengthening mechanism of layered RGO in the composite was analyzed by molecular dynamics simulation. Confinement on crack propagation and strain energy consumption by sliding of layered RGO were identified as the reason for maintaining the high toughness of the composite, and stress transfer, grain refinement and dislocation strengthening were contributed to the high tensile strength. • RGO/Cu composite with a layered structure was prepared by layer-by-layer electrodeposition. • Compared with pure copper, the tensile strength of 29-layer RGO/Cu increased by 34.2 %, while the toughness remained unchanged. • The toughening and strengthening mechanism of layered RGO in the composite was analyzed by molecular dynamics. [ABSTRACT FROM AUTHOR]

A completely nickel-aluminum-copper (Ni-Al-Cu) layer was obtained through thermal diffusion process on a nickel-aluminum-bronze (NAB) substrate. The cumulative mass loss of the NAB alloy during the cavitation erosion tests was about 6.4 times and 5.5 times as large as that of the Ni-Al-Cu layer in distilled water and 3.5 wt% sodium chloride (NaCl), respectively. Electrochemical measurements under quiescence and cavitation erosion conditions were conducted to investigate the synergistic effects of cavitation erosion and corrosion. The results showed that the synergism had measurable effect on the cavitation erosion-corrosion process for both the NAB alloy and the Ni-Al-Cu layer. The total contribution of the cavitation erosion component including W E and W CIE was more than 80% and W E occupied the largest percentage. Thus, the improved cavitation erosion resistance of the Ni-Al-Cu layer was mainly due to mechanical factors, which implied a homogeneous and refined microstructure and the formation of hardened Ni 3 Al phase. [ABSTRACT FROM AUTHOR]

ZnAlCe layered double hydroxide intercalated by molybdate (ZnAlCe MoO 4 LDH) was successfully synthesized by using co-precipitation method, and the morphology, structure of ZnAlCe MoO 4 LDH were observed and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) techniques. The inhibition behavior of ZnAlCe MoO 4 LDH for Q235 steel in 3.5%NaCl solution was determined by polarization curves, electrochemical impedance spectroscopy (EIS), inductively coupled plasma mass spectrometer (ICP-MS) and X-ray photoelectron spectrometer (XPS) methods. The results shows that the synthesized ZnAlCe MoO 4 LDH has a lamellar structure with a particle size of 0.1–2.0 μm, an average thickness of 30 nm, and a basal plane spacing of 0.898 nm. Compared with the addition of ZnAl layered double hydroxide intercalated by nitrate (ZnAl NO 3 LDH) and ZnAl layered double hydroxide intercalated by molybdate (ZnAl MoO 4 LDH) in 3.5% NaCl solution, Q235 steel in 3.5%NaCl + ZnAlCe MoO 4 LDH solution has a lower corrosion current density, larger polarization resistance and a higher inhibition efficiency. The addition of ZnAlCe MoO 4 LDH will reduce the chloride concentration in 3.5% NaCl solution by the anion exchanged with molybdate, and improve the corrosion resistance of Q235 steel owing to the formation of passive film with the composition of ferrous or iron molybdate and deposition film with zinc and cerium hydroxides. [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]

The initiation of corrosion pits in pipeline steels plays an important role in the development of stress corrosion cracking. In order to reveal the effect of inclusions on corrosion initiation sites and also to clarify contradictory results from previous literature, we proposed an ex situ characterization method that is allowed to characterize exactly the same inclusion or location of the surface of steel before and after corrosion tests. The time-dependent corrosion behaviour of the inclusions and the surrounding X100 steel matrix at the same area before and after early stage immersion in a near-neutral pH bicarbonate solution was investigated by ex situ scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and localized electrochemical impedance spectroscopy (LEIS). The sizes of most inclusions in X100 steel are below 3 μm. The results challenge the long-held opinion of previous work that corrosion pit initiations are related with the inclusions. It has been found that most of the inclusions remain stable (intact) during the whole testing time although severe corrosion occurs on the matrix of the steel. The chemical composition of the inclusion greatly affects the chemical stability of the inclusion. SiO 2 inclusions and complex inclusions with a high SiO 2 content remain intact although obvious general corrosion occurs on the steel matrix under the investigated immersion period. Inclusions with little Si, such as Al–Mg–Ca–O enriched inclusions, totally disappear after certain immersion time. During the immersion, the corrosion product tends to deposit at the interstice between the inclusion and steel matrix. [ABSTRACT FROM AUTHOR]

Electrodeposition of metals and alloys in ionic liquids has been employed in a broader range of fields. Issues regarding the evolution of hydrogen, toxicity of reagents can be overcome by utilizing ionic liquids. This review outlines the current state of electrodeposition of various types of metals and their alloys in ionic liquids with particular focus on the work within the last decade. The metals are categorized into four groups and special attention is paid to the reactive metals that cannot possibly be deposited from traditional aqueous solutions. [ABSTRACT FROM AUTHOR]

Highlights: [•] Diffusion coating treatment for Mg alloys in Al-containing molten salts. [•] The diffusion coating process was carried at lower temperatures (280–400°C). [•] The diffusion kinetics of the formed intermetallic coatings were investigated. [•] The interdiffusion coefficients and activation energies for each phase were obtained. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effect of heating rates on ferrite recrystallization was investigated. [•] Effect of heating rates on austenite formation was demonstrated. [•] Interaction between the two stages was analysed. [•] Various microstructures were obtained by different heating rates. [ABSTRACT FROM AUTHOR]

Highlights: [•] SiC particles were coated with α-Al2O3 by sol–gel technology. [•] The Ni/CSp composite was fabricated by electrodeposition. [•] The yield strength of Ni/CSp was increased by more than six times of pure Ni at 600°C. [•] SiC enhanced strength by inhibiting grain growth and interacting with dislocations. [•] Cracking of coated particles demonstrated the result of load transfer strengthening. [ABSTRACT FROM AUTHOR]

Abstract: This study reviews the recent progress in preparation and properties of diffusion coatings on magnesium alloys. Surface alloying of magnesium alloys by diffusion coatings has been considered as an effective approach to providing the protection of magnesium alloys because of the following distinct potential advantages. Firstly, the diffusion coating has high adhesion strength since there is a strong metallurgical bond between the coating and the substrate. Moreover, the good electrical conductivity of the coated magnesium alloy can be maintained and thus its electromagnetic shielding property will not be lost. In addition, the alloyed layer comprises of intermetallic compounds, which can improved both the corrosion resistance and the mechanical properties. Therefore, various methods have been developed in an effort to fabricate diffusion coatings on magnesium alloys. This review begins with the basic principles and challenges of fabricating diffusion coatings on magnesium alloys. The types and principles of coating methods are next described. The processes of preparing diffusion coatings can be categorized into two groups: (i) one-step processes including pack cementation, vacuum aluminizing, chemical vapor deposition and molten salt bath; (ii) multi-step processes such as surface mechanical attrition treatment plus pack cementation and post heat treatment of the metallic coatings. Based on understanding the principle of each coating process, the varied microstructures depending on the processing methods and parameters, are highlighted. The corrosion and mechanical properties of the coatings are also discussed on the basis of literature data. In particular, the corrosion property especial the passivation behavior of the diffusion coating is strongly influenced by the processing parameters and the subsequent coating microstructure. Through the experimental results obtained by various researchers, the coating process–microstructure–property relationships are discussed. This review closes with an outlook on areas that should be addressed in the future work. [Copyright &y& Elsevier]

Abstract: The relationship between surface functional groups and electrochemical behaviors of polyacrylonitrile (PAN)-based carbon fibers (CFs) differentiated by oxidation treatment in air was studied. The chemical character of the CFs surface was estimated by X-ray photoelectron spectroscopy (XPS) and the electrochemical behavior of treated CFs in CuSO4 plating solution was studied by electrochemical setup. The influence of functional groups on the morphology of copper deposits was characterized by field-emission scanning electron microscopy (FESEM). It was found that the O/C atomic ratio rose rapidly from 23.05% (as-received carbon fibers) to 42.83% as the oxidation temperature was increased to 400°C and the content of –C highest. Concentrations and types of the functional groups on CFs surface showed a close connection with the electrochemical response of CFs in CuSO4 plating bath. It was showed that Cu electrodeposition was the interaction of applied voltage and the reduction of surface functional groups. With the functional groups increased, the quantities of the Cu nuclei increased, further the morphology of deposited Cu was affected. [Copyright &y& Elsevier]

Abstract: A continuous Mg–Al intermetallic coating was fabricated on an AZ91D Mg alloy in molten salts in the lower temperature range from 300°C up to 400°C. The coating consists of a single Mg17Al12 intermetallic layer or both Mg17Al12 and Mg2Al3 intermetallic layers, depending on the treatment temperature. In contrast to the conventional powder pack cementation process, active Al atoms can be formed at a lower temperature in molten salts, which contributes to the lower temperature formation of continuous intermetallic layers. The intermetallic layer markedly improves the hardness as well as the corrosion resistance of the AZ91D Mg alloy. Furthermore, the continuous intermetallic layer exhibits passive behaviour in 3.5wt.% NaCl solution, which is attributed to the homogenously distributed intermetallic phases. [ABSTRACT FROM AUTHOR]

Abstract: Ni–Co–P hollow spheres (HSs) with different component ratios were fabricated by autocatalytic reduction method. With an increase of cobalt content, coercivity of hollow spheres increased because of Co hcp structure with high magnetocrystal anisotropy. The microwave properties of Ni–Co–P HSs were investigated in the range of 2–18GHz. Both permittivity and permeability of spheres–wax composites increased with the increase of cobalt content. For the Ni–Co–P hollow spheres, the minimum reflection loss (RL) (−41.7dB) was found at 6.3GHz with a thickness of 2.5mm. Additionally, with the increase of cobalt content, the minimal reflection loss increases obviously, which means that introducing Co into Ni improves the microwave absorption capability. [Copyright &y& Elsevier]

Abstract: Fe–36wt.%Ni alloy film was prepared through direct current electrodeposition to investigate the effect of 2-butyne-1,4-diol(BD) on the microstructure and internal stress of the deposited films. The deposits composition was not affected by the addition of BD when its concentration in the electrolyte was above 0.2g/L. All the film surfaces exhibited a flat and compact appearance. X-ray diffraction analyse revealed a phase of solid solution of iron in face centered cubic nickel, and the addition of BD caused strong (111) texture. The measurement of internal stresses showed a decrease of compressive stress with addition of BD in the electrolyte, and at the concentration of 0.4g/L, tensile stress showed up in the film and caused some micro-cracks parallel to the surface. [Copyright &y& Elsevier]

Abstract: Electroless plating of Cu–Ni–P alloy on polyethylene terephthalate (PET) fabrics and effect of plating parameters on the properties of alloy-coated fabrics were investigated. The deposition rate increased with the increase of temperature, pH and nickel ion concentration. The addition of K4Fe(CN)6 to the solution could reduce the deposition rate and make the deposits become more compact. The color of the deposits also had a corresponding improvement, changing from dark-brown to copper-bright with the addition of K4Fe(CN)6 to the plating solution. The deposits have an intensified copper (111) plane orientation with the addition of K4Fe(CN)6 to the plating bath. The surface electrical resistance of alloy-coated fabrics increased with increase of nickel ions concentration in the solution. The addition of K4Fe(CN)6 to the solution reduced significantly the surface resistance of alloy-coated fabrics. The conductive fabrics with high shielding effectiveness could be prepared at the optimum condition with 0.0038M nickel ions and 2ppm K4Fe(CN)6. As the deposit weight on the fabric was 40g/m2, the shielding effectiveness of alloy-coated fabrics was more than 85dB at frequency ranging from 100MHz to 20GHz. [Copyright &y& Elsevier]

Abstract: In this paper, a new method to prepare Al–8.5Fe–1.3V–1.7Si (FVS0812) alloy by spray co-deposition with added its over-sprayed powders was studied. Two kinds of powders which are different in particle size (≤43, 43–74μm) were used in the new process. Under the same experimental conditions, the alloys were produced by spray deposition without powders and the spray co-deposition. The deposited alloys were subsequently hot extruded with an extrusion ratio of 16:1 at 450°C. The results showed that the addition of over-sprayed powders refined the microstructure and improved the mechanical properties, and the effect of the fine over-sprayed powders was more evident than that of the coarse powders. The ultimate tensile strength was enhanced from 360.5MPa (without powders) to 433.3MPa (≤43μm) and 392.4MPa (43–74μm). The mechanical properties increase is mainly due to the over-sprayed powders pulverizing melt effectively, absorbing heat greatly and increasing the number of heterogeneous nuclei in matrix, which result in the enhancement of cooling rate and the refinement of microstructure. [Copyright &y& Elsevier]

During the 120 years' development route of the nickel-based cathode, lots of efforts have been made to realize alkaline batteries with better performance. From the earliest Edison's nickel-iron battery to the modern nickel-based battery, progress is always accompanied by backtracking steps, exhibiting a spiral-rising feature. In the early researches, composition and structures of cathodes gained most of the attention while since the 21st century, the morphology of the active materials has taken most of the research areas. Although the research interests varied with the development of technology, the core issues in material science still exist and cause unfavored problems, including insufficient energy density, limited cyclability, and inadequate rate performance. This review mainly focuses on describing a comprehensive development story of the nickel-based cathode and explaining the reasons for technology alteration. In the end, issues needed attention for future researches are presented to provide practical guidance. Image 1 [ABSTRACT FROM AUTHOR]