## 3 Results and Discussion
### Statistical Analysis
However, the third level increases noise, which reduces the precision of controlling both parameters, explaining the decrease in the S/N ratio at this level. These insights, derived from the analysis of the main effect plots, confirm that the combination of A3:B3:C2 is indeed the optimal setting, ensuring the highest levels of both microhardness and compressive strength while maintaining process stability and precision. The experimental testing results for microhardness can be effectively illustrated through the color-coded maps of microhardness (Figure 8a-c). The distinct shades in color-coded maps represent the relationship between microhardness and process parameters of powder metallurgy. Figure 8a highlights the dependence of microhardness on compaction pressure and sintering temperature. From the figure, it was evident that an increase in both compaction pressure and sintering temperature leads to an increase in microhardness values. This is because higher compaction pressure results in denser material, while higher sintering temperature encourages better bonding and grain growth, which in turn, improves the overall hardness of the material. The color-coded maps show the distribution of microhardness values: light blue indicates values from 85 HV, while dark blue corresponds to values below 80 HV. The green color shades range from 90 HV (lightest green) to over 105 HV (darkest green). These color gradients allow clear identification of areas where microhardness was higher or lower, providing useful insights into how varying process parameters affect the material's hardness. Figure 8b shows the correlation between compaction pressure and sintering time, and Figure 8c focuses on the influence of sintering temperature and sintering time. The data demonstrate that increasing both compaction pressure and sintering temperature leads to a rise in microhardness values, which suggests that these factors contribute positively to the material's overall hardness. Furthermore, the analysis of compaction pressure and sintering time (Figure 8b) indicates that microhardness peaks when sintering time was extended from approximately 55 to 70 min, at higher compaction pressures. This was due to the fact that extending sintering time allows more time for diffusion and bonding between particles, which enhances microhardness, but excessive time may result in grain coarsening, thus reducing the hardness. The color coding in Figure 8 helps to identify regions with varying levels of microhardness. The lowest values were marked in dark blue, providing a clear visual indication of areas that exhibit reduced hardness. This was particularly useful for visualizing the areas where the process parameters were not optimized, and where adjustments were necessary to achieve the desired performance characteristics. These insights were critical for understanding how process variables influence the material's mechanical properties, guiding the optimization of sintering parameters to achieve desired performance characteristics. Similarly, the experimental testing results for compressive strength can be effectively illustrated through the color-coded maps of microhardness (Figure 9a-c). The distinct shades in color-coded maps represent the relationship between microhardness and process parameters of powder metallurgy. As with microhardness, the color-coded maps for compressive strength clearly display the influence of the process parameters on the material's strength. The lowest compressive strength values were marked in shades of dark blue, ranging from 410 MPa (lightest blue) to values below 390 MPa (darkest blue), while the highest compressive strength values were indicated in green, with the lightest green shade representing 420 MPaand the darkest green representing up to 450 MPa. Figure 9a highlights the dependence of compressive strength on compaction pressure and sintering temperature.