The kinetics of hydrogen absorption/desorption within nanostructured composite Ni79.1Co18.6Cu2.3 alloy using resistometry

Electrodeposition, Microstructure and Magnetic Properties of Nickel-Cobalt-Copper Alloy Powders

“…Specifically, during the alloy deposition, copper is co-deposited at the limiting diffusion current at high overpotential, which leads to the rapid formation of nuclei and generation of deposits having large surface areas. 50,59,60 The current efficiencies of alloy deposition decrease with increasing current density. At the same current density, the current efficiencies of the copper-containing alloy are higher by about 12% than those of the alloy without copper.…”

“…49 The incorporation of Cu into the deposited FCC-structured solid solution of Co in Ni causes the formation of smaller nanocrystals having a high mean microstrain value and a high density of chaotically distributed dislocations. 49,50 The overpotential for Cu deposition at Ni-Co-Cu alloy deposition current densities higher than 100 mA cm −2 is high. At high overpotentials, the critical radius of the nucleus and the number of atoms in the critical nucleus is smaller than at low overpotentials.…”

“…The greater density of nuclei on the deposit surface causes the formation of smaller crystalline grains, which exhibit higher internal microstrain values and a higher density of chaotically distributed dislocations. 49,50,59,60 As the mean nanocrystal size decreases, the mass percentage of the amorphous matrix located between the nanocrystals increases. [61][62][63][64] Therefore, Ni/Co electrodeposits with Cu have a larger amount of the amorphous phase compared to those without copper.…”

“…However, there are studies evaluating the electrodeposition and characteristics of nickel-cobalt powders. [38][39][40][41][42][43][44][45][46][47][48][49][50] The deposition of small amounts of copper with iron group metals ensures the obtainment of powders having an appropriate mean particle size, nanosized crystalline grains, good magnetic properties and high corrosion resistance. [51][52][53][54][55][56][57][58][59][60] Electrodeposited ternary nickel-cobalt-copper z E-mail: smilica84@yahoo.com alloys are used as magnetic or magnetoresistive materials, which have better corrosion resistance than the Co-Cu system.…”

Kinetics of the Lattice Response to Hydrogen Absorption in Thin Pd and CoPd Films

“…Reversal of the resistance response polarity from positive to negative at the critical resistivity threshold of about 50 μΩ cm in 4% H 2 atmosphere has been demonstrated in thin Pd, thick PdSiO 2 granular mixtures and CoPd alloy films with variable resistivity [ 22 ]. Earlier observations of the reduced resistance in the hydrogenated state were attributed to the lateral swelling of disconnected Pd clusters [ 23 , 24 , 25 , 26 , 27 ], contribution of hydrogen electrons to the conducting band [ 28 ], and even to the onset of room temperature superconductivity [ 29 ]. It seems, however, that inflation of a film thickness provides a simple and consistent explanation of the observed effects in both continuous and discontinuous hydrogenated films [ 22 ].…”