## 3 Results and Discussion  
### Influence of Deposition Time and Cataphoretic Voltage on Coating Characteristics  
Figure 4 illustrates the significant impact of varying both the duration of deposition and the applied voltage on the thickness of the resultant layer. It has been identified that concentration is also a critical factor under these conditions. At a concentration of 15 g\(\cdot\)L\({}^{-1}\), the maximum achievable layer thickness is attained with a coating voltage of 300 V. Following a deposition period of 3 min, this maximum thickness measures 21.42 \(\upmu\)m. As the deposition time is extended, the thickness further increases, reaching 22.02 \(\upmu\)m after 7 min. The minimum recorded thickness of 18.43 \(\upmu\)m occurs at a coating voltage of 200 V with a 3 min deposition time. With an increase in time, the thickness also rises, achieving 21.78 \(\upmu\)m after 7 min. The disparity between the maximum and minimum thicknesses at 3 min of cathodic electrocoating is 2.99 \(\upmu\)m, while this difference diminishes to 0.24 \(\upmu\)m after 7 min. When the concentration is adjusted to 35 g\(\cdot\)L\({}^{-1}\), a relatively uniform thickness distribution is observed across the entire spectrum of tested voltages. In every instance, the thickness exhibits a proportional increase with time. Notably, at this concentration, the lowest thickness values are recorded at a coating voltage of 200 V, where the thickness measures 14.82 \(\upmu\)m after 3 min and reaches 16.63 \(\upmu\)m following an extended deposition time of 7 min. Figure 3: Analysis of residual th. The subsequent layer thickness values increase by approximately 0.42 \(\upmu\)m as a result of changes in the specified coating voltage and duration. A maximum thickness of 16.43 \(\upmu\)m is achieved at a coating voltage of 300 V after 3 min of deposition. As the deposition time increases to 7 min, the thickness reaches 18.24 \(\upmu\)m. When the degreasing concentration is adjusted to 55 g\(\cdot\)L\({}^{-1}\), and the cathodic electrocoating (KTL) process lasts for 3 min, the layer thickness becomes more uniform, with a variance of 0.23 \(\upmu\)m. The lowest thickness of 17.16 \(\upmu\)m is produced at a coating voltage of 200 V, and by extending the deposition time to 7 min, the thickness increases to 17.42 \(\upmu\)m.  
The greatest thickness is observed at a voltage of 300 V, where after 3 min of deposition, the thickness reaches 17.39 \(\upmu\)m, and with 7 min of deposition, it reaches a peak of 20.41 \(\upmu\)m. The results also confirm the conclusion of [PERSON] et al. [30] and [PERSON] et al. [31]. Figure 5 illustrates that, by varying the deposition time in cathodic electrocoating and KTLU at the maximum experimental values, while simultaneously adjusting the concentration to 15 g\(\cdot\)L\({}^{-1}\), the minimum thickness is achieved at a coating voltage of 200 V, where after a deposition time of 3 min, the thickness reaches 21.03 \(\upmu\)m. At this voltage, with increasing time, the thickness decreases, reaching 19.57 \(\upmu\)m after 7 min. A similar reduction in thickness is observed at voltages of 226 V and 250 V. However, at 250 V, the decrease in thickness over the KTL deposition period is only 0.08 \(\upmu\)m. In contrast, voltages of 275 V and 300 V result in an increase in thickness throughout the entire deposition time. The difference between the maximum and minimum thickness at a 3 min deposition is 0.24 \(\upmu\)m. A voltage of 300 V ensures the greatest thickness, reaching 22.56 \(\upmu\)m after 7 min of KTL deposition. When the concentration is changed to 35 g\(\cdot\)L\({}^{-1}\), the thickness levels increase uniformly with rising voltage. Figure 4: The influence of KTL deposition time and KLT voltage on the change of the formed layer at the minimum values of the design of experiments methodology. The minimum thickness is observed at 200 V, where the thickness is 13.65 \(\upmu\)m after 3 min and 15.46 \(\upmu\)m after 7 min. The thickness increases by 0.42 \(\upmu\)m as the voltage rises to the defined value.