Study of Ni-TiO2 nanocomposite coating prepared by electrochemical deposition

Advances in materials performance often require the development of composite system. Nanocomposites containing titanium oxide nanoparticles in a nickel matrix have been prepared by means of electrocodeposition process from nickel plating bath an sulphate bath. The nanocomposite coatings were obtained by codeposition of the TiO2 nanoparticles (mean diameter 21 nm) with nickel during plating process. The surface morphology and microstructure of the nickel matrix was significantly altered due to the presence of titania nanoparticles. In the case of both nickel baths, the Vickers microhardness showed a tendency to increase with the amount of particle incorporation. The corrosion behaviour of the electrodeposited nickel in 0.5M Na2SO4 and 0.5M NaCl was studied using electrochemical methods. The corrosion rate calculated by polarization potentiodynamic curves obtained after 30 min and 1 h from immersion in solution is bigger for nanostructured coatings in 0.5M Na2SO4 (5.92 μm/year) and a little bit smaller in 0.5M NaCl (3.77 μm/year)

Electrodeposition of Ni/Cu multilayer nanowires using alumina template

Nickel/copper multilayer nanowires have been electrodeposited in sulphamate electrolytes containing nickel and copper ions by alternating potential pulses using alumina template. In order to compare the wires and bulk behavior, nano-thick Ni/Cu multilayers bulk were electrodeposited on sputtered gold silicon under the same conditions. The optimal deposition potential range for nickel was between -1.2 and -1.25 V vs. a saturated calomel electrode (SCE) to minimize the copper content and to prevent formation of nickel hydroxide and nickel hydride. The optimal deposition potential range for copper was between -0.4 and -0.8 V vs. SCE. Magnetic properties of Ni/Cu multilayers were determined at various Ni and Cu layer spacing

Electrocodeposition of Ag/TiO2 nanocomposite coatings in cyanide free electrolytes

Synthesis and characterisation of nanocomposite coatings consisting of Ag doped TiO2 nanocrystals at different concentrations have been carried out. Composites were obtained by electrochemical deposition using a slightly alkaline cyanide free electrolyte containing AgNO3 as Ag precursors. Morphology and crystalline structure of the Ag/TiO2 hybrid materials with up to 8?5 vol.-%TiO2 were compared with those of pure Ag coatings. The presence of TiO2 nanoparticles in the bath led to an increase in the degree of orientation of crystallites on [111] and [311] crystallographic directions. During the electrodeposition, the presence of TiO2 particles at the electrode/electrolyte interface retards the crystal growth, and hence, the composites possess smaller grain sizes. The surface morphology observations show that TiO2 nanocrystals were attached within the metallic matrix surface, and the appearance of the surface indicates a porous structure with different geometrically shaped grains; this is also confirmed by atomic force microscopy measurements

Electrodeposition of Ni/Co and Ni Magnetic Nanowires using Allumina Template

Nickel and nickel-cobalt alloy nanowires were fabricated through template-assisted electrochemical deposition method and sandwiched between two caps of electrodeposited pure gold. Free standing porous alumina templates were prepared and used for the synthesis of the ordered nanowires. The morphology and composition of as-deposited nanowires were determined by scanning electron microscope. Nanowires were characterized by a diameter of 70 nm, as the alumina template pores diameter, and by a length in the range of 1.5-2.5 μm. Backscattered electron signal showed the presence of Au and Ni or Ni-Co sandwich, highlighting a well defined and void free interface between the gold caps and the Ni or Ni-Co layer. Particular optimization has been considered for the subsequent magnetoresistance characterization of nanowires. Angular dependence of magnetoresistance has been measured as a function of temperature from in-plane to perpendicular magnetic field configuration. Anisotropic magnetoresistive measurements suggested a magnetization process by magnetization rotation from nanowire axis towards in-plane orientation