**e.** Bath composition

dictory effects of temperature increase on the thermodynamic and kinetic driving force of nucleation process. As the electrolyte's temperature increases, the thermodynamic driving force of crystallization decreases and the critical size of the nucleus will increase. This will lead to lower nucleus densities and formation of coarse grain. On the other hand, the increase in temperature leads to enhancement of the kinetic driving force. This results in an increase in

Agitation of the plating solution is important in determining particle incorporation. There are various methods of agitation employed include circulation by pumping, purging, of air, ultrasonic agitation, and the plate pumper technique. In general, if the agitation is too slow (laminar flow), the particles in the bath may not disperse completely, except when their density is low. If the agitation is too high (turbulent), particles will not have sufficient time to get

Increase in the bath agitation in the parallel plate electrode setup has been found to increase the amount of particles co-deposited within the electroplated film for the Ni-Al2O3 and Ni-TiO2 systems. When the agitation is increases, a greater number of particles arrive at the electrode surface and the amount of particle incorporation in the metal film increases. However, if the agitation is too intense, the residence time for the particles at the electrode surface is insufficient and the particles are swept away before they can be incorporated into the growing metal film [25]. The amount of co-deposition has also been observed to decrease

Particles can be characterized by their composition and crystallographic phase, as well as by their size, density, and shape. The particle composition can have a dramatic impact on the amount of incorporation obtained for a particular bath composition. For instance three times more TiO2 than A12O3 has reportedly been incorporated into a Ni matrix, under the same deposition conditions. The particle size also effects on the amount of co-deposited particles in the composite coatings. For example when the particle size in the electrolyte increases then amount of adsorbed ions on the surface increases, which leads to the increase in the migration velocity of the particles and also results in a higher columbic force of attraction, leads to increase in the amount of the particles. But the density of particles in the coating decreases as

The electrode/particle interaction will be affected by the particle properties, such as material type, shape, size, surface charge, concentration, and dispersion in the bath. The co-deposition of nano-sized particles produces a composite coating with a much higher hardness than that achieved with micron-sized particles. The smaller the particle, the more difficult the codeposition into the metal matrix due to the high tendency of agglomeration. In addition, the smaller the particle size, the greater the effect of colloidal properties (van der Waals, electro‐

attached to the surface, and this results in poor particles incorporation [25].

in the Cu-SiC and Cu-CrB2 systems with increasing agitation [24].

the particle size in the electrolyte increases [25]*.*

static, and solvent interaction forces) [24].

the rate of nucleation and thus fine grains formation [25].

**c.** Bath Agitation

10 Electrodeposition of Composite Materials

**d.** Particle Characteristics

The composition of the co-deposition bath is not only defined by the concentration and type of electrolyte used for depositing the matrix metal, but also by the particle loading in suspen‐ sion, the pH, and the additives used. A variety of electrolytes have been used for the electro co-deposition process to form metal matrix of copper include acid copper sulphate bath, alkaline pyrophosphate bath. Electrolyte concentrations typically range between 100-600 g/l and the particle loading in suspension has ranged from 2-200 g/l [25].

According to Narasimman et al. [38], various additives can be used for preventing the agglomeration of particles, increasing the volume fraction of reinforcing particles in the deposit, and providing good dispersion and thus high hardness. The addition of surfactants plays a role in modifying the surface charge and reducing the particle agglomeration, thus improving their electrostatic adsorption on the cathode surface. As a result of decreasing the agglomeration of particles, the amount of effective particles would be significantly increased, resulting in higher amounts of the reinforcing particles. The addition of surfactants changes the zeta potential of the particles.

The effect of additives in the plating bath on the microstructure and physical properties of deposits was reported by many researchers. For example, the addition of saccharin to plating electrolyte was found to improve the ductility and brightness. The role of additives on a grain refining can be summarized as follows:

