## 3 Results and Discussion
The negative value of the \(Ssk\) parameter indicates a concentration of material near the apices of the profile or may be the result of scratches, to which this parameter is very sensitive. The lack of any correlation between the slope coefficient \(Sku\) (which measures the sharpness of the profile ordinate density distribution curve) and the layer production parameters, indicates the presence of high and sharp apices or deep valleys on their surface profile. Examinations of the chemical composition of the oxide layers were performed with an EDS spectrometer on cross-sections of the layers. Table 5 shows the chemical composition of an example of a layer with deviations. By weight, oxygen accounts for 31.89% of the chemical composition of the layer with a +/\(-\)0.39% error, and aluminum accounts for 68.11% with a +/\(-\)0.28% error. The above results are consistent with the composition resulting from the stoichiometric calculations of aluminum oxide. Figure 3 shows the EDS spectrum of the oxide layer. Figure 4 show images of the nanomorphology of the oxide layer surfaces for all the electrolyte temperatures and current densities. The images show the surface porosity, characteristic of aluminum oxide layers, which is made up of nanopores of a cylindrical structure. When the formation of a layer begins, single rows of cells are formed in the initial phase. These form at the grain boundary, where the natural oxide layer has the lowest electrical resistance. During formation of the layer, a single cell \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Sample** & \(S\)**\(a\) [\(\upmu\)m]** & \(S\)**\(q\) [\(\upmu\)m]** & \(Sp\) [\(\upmu\)m]** & \(Sv\) [\(\upmu\)m] & \(St\) [\(\upmu\)m] & \(Ssk\) & \(Sku\) & \(Sz\) [\(\upmu\)m] \\ \hline A & 0.277 & 0.348 & 1.952 & 1.488 & 3.44 & \(-\)0.209 & 3.402 & 2.918 \\ B & 0.298 & 0.384 & 3.312 & 1.344 & 4.656 & 0.62 & 8.151 & 3.862 \\ C & 0.294 & 0.378 & 3.696 & 1.168 & 4.864 & 0.674 & 8.639 & 4.186 \\ D & 0.366 & 0.49 & 3.216 & 2.976 & 6.192 & \(-\)0.589 & 7.29 & 5.757 \\ E & 0.323 & 0.477 & 5.824 & 4.368 & 10.192 & \(-\)0.733 & 20.315 & 8.214 \\ F & 0.319 & 0.423 & 1.28 & 2.672 & 3.952 & \(-\)0.984 & 7.462 & 3.875 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Amplitude parameters of surface geometric structure. Figure 3: EDS spectrum of oxide layer. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Element Line** & **Weight \%** & **Deviation \%** & **Atom \%** & **Deviation \%** \\ \hline O K & 31.9 & +/\(-\)0.4 & 44.1 & +/\(-\)0.5 \\ Al K & 68.1 & +/\(-\)0.3 & 55.9 & +/\(-\)0.2 \\ \hline Total & 100.00 & & 100.00 & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Chemical composition of oxide layer. is in linear contact with the six cylindrical cells surrounding it, thereby forming a hexagonal column. At the same time, the pore also changes into a star-shaped pore with six arms pointing towards the corners of the hexagon. Computer analysis of the surfaces was performed on microscopic images of the oxide layers. All images of the oxide layer surfaces were processed using the same procedures. Based on the obtained data, histograms were prepared with the nanopore surface distribution in individual layers (Figure 5) and a table with the stereological parameters of the surface layers (Table 6). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Surface Share** & **Number of** & **Average Area** \\  & **Nanoporosity [\%]** & **Nanopores/[\(\mu\)m\({}^{2}\)]** & **Nanopores [nm\({}^{2}\)]** \\ \hline A & 5.5 & 31.4 & 1741 \\ B & 18.7 & 43.9 & 4294 \\ C & 15.4 & 38.0 & 4016 \\ D & 4.1 & 24.7 & 1637 \\ E & 6.5 & 51.7 & 1265 \\ F & 11.8 & 36.2 & 3265 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Stereological parameter values from computer analysis of surfaces. Figure 4: SEM image of nanopores in oxide layers (designations of samples in Table 1).