Electrodeposited Ni Layers Research Articles

Controlling electrodeposited Ni layers by different-sized graphene oxides enables conductive e-textiles for the highly sensitive electrochemical detection of glucose

Controlling electrodeposited Ni layers by different-sized graphene oxides enables conductive e-textiles for the highly sensitive electrochemical detection of glucose

Enhancement of shear stability of a Fe-based amorphous alloy using electrodeposited Ni layers

Tensile and fracture behaviors of sandwich-structured composites consisting of a Fe-based amorphous layer with a constant thickness and ultrafine-grained Ni layers with different thicknesses were investigated. The results indicate that the initiation and the stable propagation of the shear band in the amorphous layer was dominated by the Ni layers due to their strong constraint role. The catastrophic fracture of the amorphous layer was postponed in the sandwich composites through properly increasing the constrained Ni layer thickness, which effectively decreased the shear stress on the shear fracture planes of the amorphous layer, and thus led to stable propagation of the primary SB characterized by the increase in the smooth region size of the shear band.

The influence of pH electrolyte on the electrochemical deposition and properties of nickel thin films

Ni thin films were electrodeposited on gold substrate from chloride solution with different pH at room temperature. The effect of electrolyte pH on Ni coatings was studied by using the cyclic voltammetry, the scanning electron microscopy (SEM), x-ray diffraction, and alternating gradient force magnetometer measurements. From electrochemical measurements, the onset potential for reduction of Ni was gradually shifted towards more cathodic scan with increase in pH; this is due to the protons in the case of low pH values and to the hydroxide ions in the case of higher pH values. The SEM study showed that a granular and compact structure of the electrodeposited Ni layers and the variation of film morphology with bath pH are established. The x-ray diffraction spectra revealed the formation of fcc structure Ni thin films with a preferential orientation along the Ni(111). The size of the deposited crystals in both the cases has been found to be in the range of 49–153 nm. Magnetic properties such as coercivity and saturation magnetization showed strong dependence on the electrolyte solution pH and consequently the crystallite size. Coercivity higher than 130–160 Oe was achieved for a pH value of 4 to 5. The differences observed in the magnetic properties were attributed to the structural changes caused by the electrolyte pH.

Morphology, structure, and magnetic properties of electrodeposited Ni films obtained from different pH solutions

Nanocrystalline nickel (Ni) films were obtained by electrodeposition from chloride aqueous solution with different pH values. The influence of electrolyte pH on the morphological, structural, and magnetic properties is studied, using scanning electron microscopy (SEM), X-ray diffraction (XRD), and alternating gradient force magnetometry (AGFM) techniques. SEM studies revealed a granular and compact structure of the surface of the electrodeposited Ni layers, and the variation of film roughness with bath pH is established. XRD analysis gives evidence of strongly textured Ni films along the (111) direction, with the face-centered cubic (fcc) structure for all baths pH. Magnetic properties such as coercivity, remanence, saturation magnetization, and squareness showed strong dependence on the baths pH and crystallite size. High coercivity was attributed to the presence of the small crystallite size of deposits. The properties of the deposit are greatly influenced by the solution pH.

Electro-deposition current density effect on Ni/PZT layered magnetoelectric composites performance

This paper considers the magnetoelectric (ME) effect in Ni/PZT layered ME composites that is related to the preferred crystallographic orientation of electro-deposited Ni layers. The Ni electro-deposition rate increases with applied cathodic current density. High (1 0 0) texture in the Ni layer was obtained at either low or high current densities, which improves the ME composite's performance. It is advantageous to increase the current density, while trying to avoid hydrogen evolution during electro-deposition to reduce the number of pinhole defects.

Characterization of texture and microstructure of electrodeposited Ni layers

AbstractThe texture and microstructure of electrodeposited Ni layers formed in an additive-free Watt's bath were investigated. The microstructure of the electrodeposited Ni layer consists of fine columnar grains extending along the growth direction. The major texture components of electrodeposited Ni layers on Ni-P substrate were (112) and (110) fibers. On the other hand, electrodeposited Ni layers on Cu substrate had a strong (110) fiber texture. In the vicinity of the interface between the electrodeposited Ni layer and the Cu substrate, obvious epitaxial regions were not observed. Many twins parallel to the growth direction were observed in the electrodeposited Ni layer. It is suggested that grains with a twin relationship grew preferentially during the electrodeposition reaction.

Formation of Strongly Biaxial-Textured Ni Layer for YBCO Coated Conductor by Electrodeposition Process

A new method of strongly biaxial-textured Ni substrate for YBCO coated conductor has been developed by electrodeposition using cube-textured cathode such as Ni single crystal, RaBiTS-processed Ni or Ni-W tape. Electrodeposited Ni layers using Ni single crystal as a cathode were characterized with /spl theta/-scan and /spl phi/-scan methods, and it showed excellent out-of-plane (/spl Delta//spl theta/=1.6/spl deg/) and in-plane alignment (/spl Delta//spl phi/=3.6/spl deg/). In addition, electrodeposited Ni layers using RaBiTS tape as a cathode show good biaxial texture (/spl Delta//spl theta/=5.7/spl deg/,/spl Delta//spl phi/=9.6/spl deg/) and smooth surface. XRD characterization shows that biaxial texture of cathode was transferred to electrodeposit and texture of electrodeposited Ni layers changes with deposition time. Finally, a CeO/sub 2/ buffer layer has been deposited by MOD process to show the compatibility of substrate with further buffer layer processing. Our modified electrodeposition process shows good possibility of providing a simple and effective way to high quality cube-textured Ni substrates for YBCO coated conductor.

Electrodeposited Biaxially Textured Ni Layer for YBCO Superconductor Oxide Films

Nonvacuum electrodeposition was used to prepare biaxially textured Ni coatings on Ni-W substrates. The samples were characterized by X-ray diffraction (including θ/2θ, pole figures, omega scans, and phi scans), and atomicforce microscopy. Pole-figure scans show that electrodeposited (ED) Ni on textured Ni-W (3 atom %) is 99.3% cube textured. Full width at half-maximum values of the ω scan and Φ scan of the electrodeposited Ni layers were comparable to the Ni-W base substrates, indicating good biaxial texturing. The buffer structures were completed on these types of seed ED-Ni layers by pulsed-laser-deposited (PLD) CeO 2 /YSZ/CeO 2 . We obtained a critical current density of 1.8 MA/cm 2 at 75.2 K in 600 Gauss magnetic field for PLD YBa 2 Cu 3 O 7 - δ /CeO 2 /YSZ/CeO 2 /ED-Ni/Ni-W.

Novel magnetic materials prepared by electrodeposition techniques: arrays of nanowires and multi-layered microwires

The fabrication process by electrodeposition routes and the study of general magnetic properties is reported for two types of nanostructured magnetic materials: (a) nickel-filled highly-ordered nanoporous alumina templates, and (b) electrodeposited Ni layers onto glass coated amorphous microwires. Arrays of Ni nanowires, about 30 nm in diameter and separated by about 100 nm, are obtained by electrodeposition into the pores of alumina membranes prepared by two-steps anodization process from highly pure aluminum substrates. Morphological studies have been performed by high resolution scanning electron microscopy (HRSEM). The study includes the optimization of preparation parameters and the magnetic characterization of the hexagonally arranged nanowire arrays, i.e. the influence of the pore diameter and the interwire distance on the coercivity of the whole nanowire array. On the other hand, multi-layered magnetic microwires have been prepared in the following sequence: a nanometric Au coat is first sputtered onto Pyrex coated FeSiB amorphous microwires followed by electrodeposition of a 500 nm thick Ni external cover. While in as-cast microwires the hysteresis loop is squared shaped (magnetic bistability), in the case of the multilayer microwire, a transverse magnetic anisotropy is induced when reducing the measuring temperature as a consequence of the stresses induced by the different thermal expansion coefficients of the various layers.