Mass transfer and electrocrystallization analyses of nanocrystalline nickel production by pulse plating

Grain boundary segregation and thermodynamically stable binary nanocrystalline alloys

“…However, the introduction of a high density of interfaces has an associated energetic penalty, and nanocrystalline materials tend to be unstable with respect to thermally activated structural changes. [9][10][11] The problem of nanostructure stability is most apparent in elemental nanocrystalline metals, such as Ni, 2 Cu, [12][13][14][15][16] Al, 17,18 and Pd, 19,20 which exhibit grain growth at very low homologous temperatures. These materials occupy a far-from-equilibrium state, which can be understood in the thermodynamic context formalized by Gibbs.…”

Electrodeposited Nanostructured Films and Coatings: Synthesis, Structure, Properties and Applications

“…Electrocrystallization occurs either by the build up of existing crystals or the formation of new ones [23]. These two processes are in competition with each other and are influenced by different factors such as plating parameters and substrate pretreatment.…”

“…These two processes are in competition with each other and are influenced by different factors such as plating parameters and substrate pretreatment. The two key mechanisms which have been identified as the major rate determining steps for nanocrystal formation are charge transfer at the electrode surface and surface diffusion of adions on the crystal surface [23,24]. The other important factor in nanocrystal formation during electrocrystallization is overpotential [23,24].…”

“…The two key mechanisms which have been identified as the major rate determining steps for nanocrystal formation are charge transfer at the electrode surface and surface diffusion of adions on the crystal surface [23,24]. The other important factor in nanocrystal formation during electrocrystallization is overpotential [23,24]. Grain growth is favoured at low overpotential and high surface diffusion rates for adions, while high overpotential and low diffusion rates promote the formation of new nuclei.…”

Effect of Surface Roughness and Structure Features on Tribological Properties of Electrodeposited Nanocrystalline Ni and Ni/Al2O3 Coatings

“…Ni/Al 2 O 3 have been extensively studied; however, considerable research has been focused on the impact of the electrodeposition parameters, especially the value and kind (direct, pulse) of the current density (Ref 11,13,(29)(30)(31) as well as the type and concentration of the applied additives (Ref 5,6), on the manufacture process and the volume fraction of the particles built in the nickel matrix. It is known that an addition of saccharin to the electrolytic bath causes grain size refinement of the materials (Ref [32][33][34][35][36][37][38]. The microstructure refinement, in turn, has a significant impact on the mechanical wear properties of the coatings.…”