Multilayer coatings having a thickness about 20 μm and consisting of different Ni–P and Ni layers were prepared by combining electrodeposition with electroless deposition. The microstructure of the ...coatings was analyzed by scanning electron microscope (SEM) and X-ray diffractometer (XRD). The corrosion resistance of the coatings was estimated by electrochemical polarization measurements and salt spray test. The salt spray test showed that the three-layer coating, whose composition is Ni–P (low phosphorus)/Ni/Ni–P (high phosphorus) from surface to substrate, exhibited the highest corrosion resistance. The time of the emergence of the first red rust spot on the coating surface can reach 936 h, which is 3.5 times higher than that of the common amorphous Ni–P alloy coatings. The electrochemical analysis revealed that the difference in the corrosion potential among layers plays a very important role in protecting the substrate from rusting.
A fully dense nanocrystalline Ni exhibited high strength of about 1200
MPa and enhanced ductility of 7.5–8.3% at strain rates of 1.04
×
10
−4–1.04
s
−1 and room temperature. The dislocation activity ...in the strain hardening stage and collective grains rotation after instability are suggested as being responsible for the enhanced ductility.
Urea oxidation reaction (UOR) is regarded as a promising strategy for efficient hydrogen production and urea-rich wastewater treatment. In this work, the Cu(OH)2 nanowire arrays directly supported on ...copper foam are synthesized via a facile in-situ etching technique. The one-dimension nanowire structure with abundant mesoporous endows Cu(OH)2 catalyst with considerable exposing active sites for the catalytic reaction. Additionally, the active substance directly grown on current collector without binder using can enhance conductivity and accelerate the charge transport. Beneficial from the above merits, the as-obtained Cu(OH)2 exhibits outstanding UOR performance with a potential of 1.49 V at 10 mA cm−2, lower than 1.62 V for oxygen evolution reaction (OER), small Tafel slopes of 86 mV dec−1, and good long-term stability. This work firstly indicates that Cu-based electrocatalysts have the promising application for excellent UOR performance and urea-rich wastewater treatment.
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•The Cu(OH)2 electrode presents a 1D nanowires structure with abundant mesoporous.•It exhibits high electrocatalytic activity toward urea oxidation reaction.•It achieves a low potential of 1.49 V at 10 mA cm−2 for urea oxidation.
The NiCo hydroxides nanosheets (NiCo–OH) decorated Cu(OH)2 nanotubes structure was fabricated via a facile solution-immersion and later solvothermal method. The internal 1D Cu(OH)2 nanotubes directly ...grown on current collector without binder using enhance conductivity, accelerating electron transport. The outer 2D NiCo–OH nanosheets provide large surface areas and considerable active sites, promoting the electrode/electrolyte contact. Beneficial from significant electrochemical synergy in conductivity and open structure, the Cu(OH)2@NiCo–OH exhibits an impressive capacity of 1.12 mAh cm−2 at 3 mA cm−2, and remarkable rate capability (71% capacity retention at 30 mA cm−2). When assembled Ni–Zn battery with Cu(OH)2@NiCo–OH as cathode and Zn plate as anode, the Cu(OH)2@NiCo–OH//Zn battery displays high energy density and power density (1.53 mWh cm−2, 31.6 mW cm−2). Therefore, the Cu(OH)2@NiCo–OH//Zn battery presents a tremendous charm in new-type energy-storage devices.
The Cu(OH)2@NiCo-OH//Zn battery upraises energy density without compromising power density (1.53 mWh cm-2, 31.6 mW cm-2). Display omitted
•Cu(OH)2@NiCo–OH were fabricated via a solution immersion and solvothermal route.•It exhibits an impressive capacity and remarkable rate capability.•Cu(OH)2@NiCo–OH//Zn battery upraises energy density and power density.
ZnO films with different morphologies were deposited on the ITO-coated glass substrate from zinc nitrate aqueous solution at 65
°C by a seed-layer assisted electrochemical deposition route. The seed ...layers were pre-deposited galvanostatically at different current densities (
i
sl) ranging from −1.30 to −3.0
mA/cm
2, and the subsequent ZnO films had been done using the potentiostatic technique at the cathode potential of −1.0
V. Densities of nucleation centers in the seed layers varied with increasing the current density, and the ZnO films on them showed variable morphologies and optical properties. The uniform and compact nanocrystalline ZnO film with (0
0
2) preferential orientation was obtained on seed layer that was deposited under the current density (
i
sl) of −1.68
mA/cm
2, which exhibited good optical performances.
► The ageing behavior of Mg–2Dy–0.5Zn alloy was investigated at 180
°C. ► Two significant ageing peaks were observed at 36
h and 80
h, respectively. ► The double-peak ageing behavior is explained by ...the microstructure observation.
Ageing behavior of Mg–2Dy–0.5Zn alloy was investigated during isothermal ageing at 180
°C. Two significant ageing peaks were observed at 36
h and 80
h, respectively. Examination of microstructure evolution during ageing revealed that 14H long period stacking ordered (LPSO) phase forms in the α-Mg matrix and its volume fraction increases, (Mg, Zn)
x
Dy particle phases precipitate and their size, distribution and amount vary, as ageing time increases. The LPSO strengthening and the precipitation strengthening are two main mechanisms responsible for the double-peak ageing behavior observed for the Mg–2Dy–0.5Zn alloy. The first ageing peak is mainly attributed to the precipitation strengthening of a large amount of the fine (Mg, Zn)
x
Dy particle phases. The second ageing peak arises mainly from the LPSO strengthening of a high volume fraction of the 14H LPSO phase.
Direct electroless Ni–P plating on the AZ91D magnesium alloy from a plating bath containing sulfate nickel was investigated in the paper. The nucleation mechanism of Ni–P deposits on the AZ91D ...magnesium alloy was studied by using XRD and SEM. The electroless Ni–P deposits were preferentially nucleated on the β-Mg
17Al
12 phase and extended to the primary and eutectic α phases of the AZ91D magnesium alloy. The effect of the acid pickle treatment time of the AZ91D magnesium alloy substrate on the electroless Ni–P plating was also investigated. With prolonging the acid pickle treatment time, the cluster of electroless Ni–P deposition became smaller and the deposits were found to be more compact. The deposition rate of electroless Ni–P plating was proportional to the acid pickle treatment time. The hardness values of the Ni–P coatings were about 660 VHN and were not influenced by the pretreatments.
In order to make clear the special deformation mechanism of nanotwinned copper, the mechanical properties of two kinds of ultrafine-grained copper, one with nano-scale growth twin in the ultrafine ...grains and another one without twin, were compared in this study. Though it hardly exhibits work-hardening capacity, the nanotwinned copper shows much higher strength combined with good ductility than the copper without growth twin. The microstructure of nanotwinned copper was separated by twins into nano-scale regions where dislocation intersections and pile-up rarely take place. That leads to the weak work-hardening capacity in nanotwinned copper. The good ductility is attributed to its enhanced strain rate sensitivity which originates from the shortened dislocation segment length. Meanwhile, both the blocking effect of twin boundary on dislocation slipping and the shortened dislocation segment length enhance the strength in nanotwinned copper.
A new smelting method to synthesize high-nitrogen nickel-free austenitic stainless steel was suggested. The synthesized steel completely consists of austenite and represents more brilliant ...anti-corrosion ability both in salt solution and sulfuric acid solution. The brilliant anti-corrosion ability is retained even after severe cold-rolling deformation, which ensures its workability in practice. The potentiodynamic polarization curves, electrochemical impedance spectroscopy, and passivating treatment were used to characterize its corrosion properties and uncover its corrosion mechanism in salt solution. X-ray photoelectron spectroscopy was used to clarify the mechanism of passivation. The results demonstrate that the steel has a more uniform and thicker passive film than traditional stainless steel due to the cooperation of nitrogen and chromium.
