The chemistry and structure of nickel–tungsten coatings obtained by pulse galvanostatic electrodeposition

Preparation and Electrochemical Behavior of an Amorphous Co–Mo Coating with a High Content of Mo

At present, alloy materials are being widely used as wear-resistant coatings due to good mechanical properties. In this paper, electrodeposition was used to prepare a Co–Mo coating. The influence of parameters on the phase, morphology, composition, and property of the coating has been studied, and the electrochemical mechanism has been deeply studied. The study of process parameters found that when the concentration of Na2Mo4 is 0.05 mol/L, the concentration of C6H5Na3O7 is 0.15 mol/L, the pH of the solution is 7, and the temperature is 50 °C, the content of Mo in a Co–Mo coating is 39.56%, and the microhardness reaches the maximum value of 503 HV. The study of electrochemical behavior found that the optimization of process parameters bringsa positive shift in the reduction potential, an increase in the exchange current density, and a decrease in charge transfer impedance. The microhardness of a Co–Mo coating prepared with the leaching solution of Mo-containing waste after component control of the plating solution is 483.6 HV, which is valuable to the high-value recycling of Mo secondary resources.

Nickel Nanopillar Arrays Electrodeposited on Silicon Substrates Using Porous Alumina Templates

Nickel nanopillar arrays were electrodeposited onto silicon substrates using porous alumina membranes as a template. The characterization of the samples was done by scanning electron microscopy, X-ray diffraction, and alternating force gradient magnetometry. Ni nanostructures were directly grown on Si by galvanostatic and potentiostatic electrodeposition techniques in three remarkable charge transfer configurations. Differences in the growth mechanisms of the nanopillars were observed, depending on the deposition method. A high correlation between the height of the nanopillars and the charge synthesis was observed irrespective of the electrochemical technique. The magnetization measurements demonstrated a main dependence with the height of the nanopillars. The synthesis of Ni nanosystems with a controllable aspect ratio provides an effective way to produce well-ordered networks for wide scientific applications.

Lattice Strain Evolutions in Ni-W Alloys during a Tensile Test Combined with Synchrotron X-ray Diffraction

Ni and Ni(W) solid solution of bulk Ni and Ni-W alloys (Ni-10W, Ni-30W, and Ni-50W) (wt%) were mechanically compared through the evolution of their {111} X-ray diffraction peaks during in situ tensile tests on the DiffAbs beamline at the Synchrotron SOLEIL. A significant difference in terms of strain heterogeneities and lattice strain evolution occurred as the plastic activity increased. Such differences are attributed to the number of brittle W clusters and the hardening due to the solid solution compared to the single-phase bulk Ni sample.

Morphological stabilization and KPZ scaling by electrochemically induced co-deposition of nanostructured NiW alloy films

We have assessed the stabilizing role that induced co-deposition has in the growth of nanostructured NiW alloy films by electrodeposition on polished steel substrates, under pulsed galvanostatic conditions. We have compared the kinetic roughening properties of NiW films with those of Ni films deposited under the same conditions, as assessed by Atomic Force Microscopy. The surface morphologies of both systems are super-rough at short times, but differ at long times: while a cauliflower-like structure dominates for Ni, the surfaces of NiW films display a nodular morphology consistent with more stable, conformal growth, whose height fluctuations are in the Kardar-Parisi-Zhang universality class of rough two-dimensional interfaces. These differences are explained by the mechanisms controlling surface growth in each case: mass transport through the electrolyte (Ni) and attachment of the incoming species to the growing interface (NiW). Thus, the long-time conformal growth regime is characteristic of electrochemical induced co-deposition under current conditions in which surface kinetics is hindered due to a complex reaction mechanism. These results agree with a theoretical model of surface growth in diffusion-limited systems, in which the key parameter is the relative importance of mass transport with respect to the kinetics of the attachment reaction.

Magnetoelectrodeposition of Ni–W alloy coatings for enhanced hydrogen evolution reaction

The electrocatalytic efficiency of electrodeposited (ED) Ni–W alloy coatings for the hydrogen evolution reaction (HER) has been improved drastically through magnetoelectrodeposition (MED) approach.

Optimization of the surface properties of nanostructured Ni–W alloys on steel by a mixed silane layer

Optimization of the surface properties of nanostructured Ni–W coatings on steel by a mixed silane layer.