## 3 Results and Discussion
### Energy-Dispersive X-Ray Spectroscopy (EDX) of Cataphoretic Layer
The wt.% profile for oxygen indicates a peak near the surface, with a concentration reaching approximately 60 wt.%. Moving towards the coating-substrate interface (about 20-25 \(\upmu\)m from the surface), the oxygen concentration drops significantly, signifying its near absence in the underlying metal substrate. The elemental map for silicon (Si) shown in Figure 14 clearly shows its predominant presence in the upper region of the sample, which corresponds to the coating layer. The silicon is evenly distributed within this layer, suggesting a well-formed and uniform coating. The weight percentage (wt.%) profile graph further supports this observation, displaying a peak silicon concentration of around 24 wt.% at the surface. This concentration decreases gradually, as it moves toward the coating-substrate interface. After this point, the silicon  
Figure 11: EDX spectrum of carbon (C). concentration becomes negligible, confirming that silicon is absent in the metallic substrate beneath the coating. The elemental map for aluminum (Al) shown in Figure 15 illustrates its predominant presence in the substrate region, situated beneath the coating layer. Within the coating, aluminum is almost absent, and a sharp increase in its concentration is observed at the coating-substrate interface. This trend is further validated by the wt.% profile graph, which shows negligible aluminum content in the upper coating layer, followed by a steep rise in concentration near the interface. The concentration of aluminum remains consistently high (around 90-100 wt.%) within the substrate, indicating that aluminum is primarily confined to the metallic substrate and does not diffuse into the coating layer. Figure 12: EDX spectrum of iron (Fe). Figure 13: EDX spectrum of oxygen (O). In conclusion, the energy-dispersive X-ray spectroscopy (EDX) analysis offers comprehensive insights into the elemental composition and distribution across a sample subjected to a cataphoretic painting process. The combination of scanning electron microscopy (SEM) imaging and EDX spectral data reveals a clear delineation between the cataphoretic coating layer and the underlying metallic substrate, with a marked transition at the coating-substrate interface. Elemental mapping and corresponding wt.% profile graphs highlight several critical features; the cataphoretic coating is predominantly composed of carbon, confirming the organic nature of the paint, while iron is primarily concentrated in the metallic substrate, with minimal presence in the coating. Minor elements, such as oxygen, silicon, and aluminum, are distributed in both layers, with oxygen primarily localized  
Figure 14: EDX spectrum of silicon (Si). Figure 15: EDX spectrum of aluminum (Al). at the coating-substrate interface, suggesting its role in surface oxidation, which may facilitate improved adhesion between the coating and substrate. Silicon is predominantly confined to the coating layer, exhibiting a uniform distribution, while aluminum shows a sharp increase in concentration near the interface, confirming its confinement to the substrate. Additionally, the EDX analysis shows that there is no significant diffusion of iron or aluminum into the coating layer, reinforcing the separation between the organic paint and the metallic substrate. The uniform distribution of silicon within the coating further highlights the consistent structure of the deposited layer. These observations substantiate the uniformity and integrity of the cataphoretic coating, and the EDX data effectively demonstrate the elemental distribution and the absence of significant diffusion between the paint and metallic substrate. This study highlights the utility of EDX in assessing coating quality and substrate interactions, providing a detailed understanding of the elemental dynamics within composite coating systems. This behavior agreed with data observed by authors [PERSON] et al. [42], [PERSON] et al. [43], [PERSON] et al. [44], [PERSON] et al. [45], [PERSON] [46], and [PERSON] et al. [47].