## 3 Results and Discussion
### Energy-Dispersive X-Ray Spectroscopy (EDX) of Cataphoretic Layer  
Energy-dispersive X-ray spectroscopy (EDX) is a very effective technique for analyzing elemental composition and assessing the quality of the interface between cataphoretic coatings and the substrate. When evaluating coating adhesion, EDX provides detailed information on the chemical composition of the coating and its interactions with the substrate. Since adhesion between coatings depends on their chemical and structural properties, EDX analysis allows the identification of whether there have been undesirable changes in composition that could affect the strength and stability of the bond. EDX also allows the detection of potential defects or inhomogeneities that may indicate adhesion problems, as well as assessing the uniformity of elemental distribution throughout the coating. Figure 10 illustrates the results of energy-dispersive X-ray spectroscopy (EDX) conducted on a sample from a cataphoretic painting process, combining a scanning electron microscopy (SEM) image with the corresponding EDX spectrum. The SEM image presents a cross-sectional view of the sample, clearly showing two distinct regions: the upper layer, representing the cataphoretic paint coating, and the lower layer, corresponding to the metallic substrate. A vertical line, labeled \"Line Data 1\", marks the analyzed region, crossing the interface between the paint layer and the substrate, enabling a detailed elemental composition analysis. The EDX spectrum, displayed beneath the SEM image, provides information on the elemental composition along the analyzed path. The \(X\)-axis represents energy levels (keV), and the \(Y\)-axis shows counts per energy unit, with peaks indicating the presence of specific elements. The spectrum reveals that the upper layer is dominated by carbon, comprising approximately 49.1 wt.%, indicative of the organic nature of the cataphoretic paint. Iron peaks, accounting for 36 wt.%, highlight the metallic substrate, likely steel. Minor peaks for oxygen (~6.6 wt.%), silicon (~4.2 wt.%), and aluminum (~4.1 wt.%) suggest the presence of oxidized compounds, paint additives, or surface contaminants. Analysis demonstrates a clear boundary between the paint layer and the substrate, indicating the uniformity of the  
Figure 10: Energy-dispersive X-ray spectroscopy (EDX) of cataphoretic layer. applied coating. The presence of oxygen at the interface points to surface oxidation, which may enhance adhesion between the organic paint and the metallic substrate. The elemental map shown in Figure 11 for carbon (C) highlights its high concentration in the upper region, corresponding to the cataphoretic paint layer. The mapping shows a uniform distribution of carbon within the coating, with a clear demarcation at the interface between the coating and the substrate. The wt.% profile graph for carbon demonstrates consistent concentration in the coating layer, peaking above 80 wt.% near the surface. Beyond the coating-substrate interface (approximately 20-25 \(\upmu\)m from the surface), the carbon concentration drops sharply, confirming its absence in the metallic substrate. The elemental map shown in Figure 12 for iron (Fe) shows its dominance in the lower region, representing the substrate. The mapping indicates a uniform distribution within the substrate, while confirming the lack of significant iron content in the cataphoretic paint layer. The wt.% profile graph for iron exhibits a minimal presence in the coating layer, with concentrations increasing sharply at the interface. Beyond the boundary (approximately 20-25 \(\upmu\)m from the surface), iron stabilizes at concentrations exceeding 60 wt.%, reflecting the composition of the metallic substrate. The oxygen (O) elemental map (Figure 13) illustrates a prominent presence in the upper region, which aligns with the cataphoretic paint layer. The distribution of oxygen appears relatively consistent throughout the coating.