**3. Conclusions**

The study of ESD deposition is useful for the wide range of application elements used and the multitude of aspects addressed (micronutrition measured in the layer section, internal stresses, roughness, conductivity, EDX analysis, and XPS analysis for the detection of types of chemical compounds obtained in postdeposition and mass and energy transfer analysis, etc.).

The chemical analysis of deposited strands using photoelectron spectroscopy reveals the presence of complex chemical compounds such as carbides, nitrides, oxides (W3C0, 375, Ti2 C, TiN, TiNO, and TiCN) in the layer, which explains the mechanical properties of the surface layer (microhardness).

The solution is multiple layers, with the advantage to obtain a greater diffusion, which leads to a better anchoring for the layer, with no effect on the surface quality.

The surface quality resulting from deposition using the pulse electric discharge method is dependent on the quality and chemical composition of the electrode. We used Ti, TiC, W, and WC electrodes, and we can conclude that Ti and TiC create much smoother surfaces than those obtained with W and WC electrodes. Titanium has a good adhesion to the surface of ferrite-perlite iron, creating compact layers, with no major bumps and few microholes. Tungsten "burns" the contact surface due to the high temperatures generated in the electric arc, does not deposit itself on the piece, but only makes superficial quenches. Titanium carbon and tungsten carbide have affinity to the ferrite base matrix creating homogeneous layers but with pronounced cracks due to the coefficient of expansion different from the base material.

It notices the influence of the chemical elements from working atmosphere (oxygen and nitrogen), leading to compound formations in the superficial layer. Thus, it notices the presence of Fe, Ti, and W oxides as well as complex nitrides and carbides.

Thermal conductivity of coated surfaces is considerable inferior from the base material. In these conditions, we can conclude that each coating is forming a thermal shield, fact that can be exploited in technical field, in case of using cast-iron for elements that must resist to thermal shocks: heating systems and burning chambers.

From metallurgical aspects point of view, for homogeneous surfaces, we can conclude that tungsten electrodes and tungsten carbide are benefic in increasing the surface hardness.

In order to obtain surfaces with superior qualities, it is possible to combine the method of deposition by impulse discharge with laser treatment or with thermal spraying treatment in order to retrieve the deposited surface in order to obtain more compact layers without cracks and with low roughness.
