Ni-based bimetallic films with 20 at.% and 45 at.% Cu and mesostructured surfaces were prepared by electrodeposition from an aqueous solution containing micelles of P123 triblock copolymer serving as a structure-directing agent. The pH value of the electrolytic solution had a key effect on both the resulting Cu/Ni ratio and the surface topology. The catalytic activity of the CuNi films toward hydrogen evolution reaction was investigated by cyclic voltammetry (CV) in 1 M KOH electrolyte at room temperature. The Cu45Ni55 film showed the highest activity (even higher than that of a non-mesostructured pure Ni film), which was attributed to the Ni content at the utmost surface, as demonstrated by CV studies, as well as the presence of a highly corrugated surface.
A novel dual-template assisted electrodeposition method to fabricate Cu/Cu 2 O porous nanowires (PNs) using polymeric micelles as a soft template and polycarbonate membranes as a hard template is reported.
Nanostructuring of metals is nowadays considered as a promising strategy towards the development of materials with enhanced electrochemical performance. Porous and fully dense CuNi films were electrodeposited on a Cu plate by electrodeposition in view of their application as electrocatalytic materials for the hydrogen evolution reaction (HER). Porous CuNi film were synthesized using the hydrogen bubble template electrodeposition method in an acidic electrolyte, while fully dense CuNi were electrodeposited from a citrate-sulphate bath with the addition of saccharine as a grain refiner. The prepared films were characterized chemically and morphologically by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The Rietveld analysis of the XRD data illustrates that both CuNi films have a nanosized crystallite size. Contact angle measurements reveal that the porous CuNi film exhibits remarkable superhydrophobic behavior, and fully dense CuNi film shows hydrophilicity. This is predominately ascribed to the surface roughness of the two films. The HER activity of the two prepared CuNi films were investigated in 1 M KOH solution at room temperature by polarization measurements and electrochemical impedance spectroscopy (EIS) technique. Porous CuNi exhibits an enhanced catalysis for HER with respect to fully dense CuNi. The HER kinetics for porous film is processed by the Volmer–Heyrovsky reaction, whereas the fully dense counterpart is Volmer-limited. This study presents a clear comparison of HER behavior between porous and fully dense CuNi films.
The melt temperature of aluminum alloys plays a significant role in determining the microstructure characteristic during continuous rheo-extrusion. However, it is difficult to measure the actual melt temperature in the roll-shoe gap. In this work, based on the basic theory of heat transfer, a calculation model for heat transfer coefficient of cooling water/roll interface and melt/roll interface is established. In addition, the relationship between the temperature at the melt/roll interface and the velocity of cooling water is investigated. Combined with the CALPHAD calculation, the melt temperature during solidification in the continuous rheo-extrusion process is calculated. Using this model, the cooling rate of an Al–6Mg (wt.%) alloy melt prepared by continuous rheo-extrusion is estimated to be 10.3 K/s. This model used to determine the melt parameters during solidification provides a reference for optimizing the production process of continuous rheo-extrusion technology.
The morphology and distribution of intermetallic compounds (IMCs), such as Al6Mn, Al2Cu, and Al12Fe3Si2, play a critical role in determining the mechanical properties of 3xxx series aluminum alloys. In this study, the compressive behavior of these IMCs was systematically investigated using the modified embedded atom method (MEAM) potential and the large-scale atomic/molecular massively parallel simulator (LAMMPS) under various temperatures and strain rates. The results show that as the temperature increases from 623 K to 823 K, both the compressive strength and elastic modulus of the IMCs decrease significantly. Al12Fe3Si2 exhibits the lowest compressive strength, ranging from 1.1 to 9.8 GPa, while Al2Cu demonstrates the highest compressive strength, ranging from 3.9 to 19.8 GPa. Within this temperature range, Al6Mn and Al3Fe show relatively poor stability. At a strain rate of 1 × 1010 s−1, the thermal sensitivity coefficients for compressive strength are 0.010 and 0.008, and those for elastic modulus are 0.173 and 0.126, respectively. In contrast, Al2Cu exhibits the best stability, with thermal sensitivity coefficients of 0.005 for compressive strength and 0.041 for elastic modulus. Furthermore, the influence of strain rate diminishes notably under lower temperatures. Across the entire temperature range, Al2Cu displays the highest overall stability, with a strain rate sensitivity index ranging from 0.3527 to 0.3738.
We present a surface modification technique that turns CuNi foam films with a high contact angle and non-sticking property into a sticky surface. By decorating with mesh-like biaxially oriented polypropylene (BOPP) and adjusting the surface parameters, the surface exhibits water-retaining capability even when being held upside down. The wetting transition process of droplets falling on its surface were systematically studied using the finite element simulation method. It is found that the liquid filled the surface microstructure and curvy three-phase contact line. Moreover, we experimentally demonstrated that this surface can be further applied to capture underwater air bubbles.