**1.5. Electro-deposition parameters**

The structure and properties of composite coatings depend on many parameters, including:


Owing to their high surface energy, reinforcement particles can be easily agglomerated. Subsequently, obtaining uniform distribution of these particles is an important aim that can be achieved in optimum parameters.

#### *1.5.1. Particle type and concentration*

Particle size influences the rate of incorporation into the metal deposit. The rate of incorpora‐ tion of metal deposit per unit volume is inversely proportional to the nanoparticles size. The volume fraction of nanoparticles in the metal deposit increases substantially when the amount of nanoparticles concentration in the solution increases. A saturation state of particles in the deposit is reached at high nanoparticle concentration in the solution.

#### *1.5.2. Pulse frequency*

Micro-hardness as well as co-deposition of particles increases on variation of frequency from 0.1Hz to 10Hz and is followed by sharp decrease from 10Hz to 100Hz frequency. For frequen‐ cies below 10Hz, reduction rate of metal ions is higher as compared to ions adsorbed on nanoparticles, which reduce the nanoparticles content in the composite coating. At very high frequency, the content of nanoparticles in composite reduced because the shorter OFF time is not enough to remove concentration gradient of nanoparticles adjacent to the cathode. Wear loss and micro-hardness of composites significantly decreases when pulse frequency increases from 10Hz to 1000Hz. Significant adhesive wear is observed at higher frequencies.
