Nanocomposite films can be deposited by electrochemical deposition of a material from a solution containing a suspension of nanometer size particles. We show that the kinetics of nanometer size particle incorporation into a growing film can be described by a model that takes into account the convective diffusion of particles to the surface and treats particle incorporation in terms of the residence time at the surface. Experimentally, particle transport can be controlled using a rotating disk electrode. We show that incorporation of 300 nm Al 2 O 3 particles into nickel films can be described by this model.
In this paper we describe a kinetic model for electrochemical deposition of nanocomposites composed of a metal matrix and inert particles. The model takes into account both the diffusion force as well as the gravitational force acting on the particles. The gravitational force is shown to be important for the codeposition of 300 nm Al 2 O 3 particles in Ni, but negligible for codepositing 50 nm particles.
Nanocomposite Ni/Al2O3 films were electrodeposited from a suspension of Al2O3 nanoparticles in aqueous nickel sulfamate solution. The volume fraction of particles incorporated increased with electrode rotation rate and decreased with deposition current density. The composition, microstructure, hardness, and magnetic properties of these nanocomposite films were characterized. The mechanical strengthening due to particle dispersion in the films was interpreted by considering an Orowan dislocation bowing mechanism. The coercivity of the films increased with increasing particle concentration in the film. The saturation magnetization showed a weak dependence on particle concentration.
We describe a technique for patterning clusters of metal using electrochemical deposition. By operating an electrochemical cell in the transmission electron microscope, we deposit Cu on Au under potentiostatic conditions. For acidified copper sulphate electrolytes, nucleation occurs uniformly over the electrode. However, when chloride ions are added there is a range of applied potentials over which nucleation occurs only in areas irradiated by the electron beam. By scanning the beam we control nucleation to form patterns of deposited copper. We discuss the mechanism for this effect in terms of electron beam-induced reactions with copper chloride, and consider possible applications.
High-quality FeCo and FeCoV thin films with Fe concentrations between 32 and 52 atom% were electrodeposited from a sulfamate solution. The grain size of the films was about 200 nm. The thickness of the films was up to several hundred micrometers. The magnetic properties of these films are characteristic of bulk FeCo alloys. The addition of small amounts of vanadium eliminated film cracking but slightly decreased the magnetic permeability.
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