## 3 Results
### Characterization of the Coatings
This fact can be explained by the higher deposition temperature at a lower bias (\(-\)25 V) that relaxes the lattice microstrain developed during deposition because of dislocation motion and boundary creation. The coating at \(-\)100 V is in a state of ion knock-on dominance, characterized by high defect levels and poor structure. Since titanium alloys are prone to scratches, it is commonly recognized that coated implants should have higher mechanical qualities. Table 3 displays the average findings of the 10 measurements of the Knoop microhardness (KH\({}_{0.005}\)) of the substrate and coatings. The highest hardness of about 3031 kgf/mm\({}^{2}\) was obtained for the rutile-composed Cu-TiO\({}_{2}\) film whereas the lowest of 1365 kgf/mm\({}^{2}\) was measured for the anatase consisting of a Cu-TiO\({}_{2}\) film. Similar findings where increased amounts of rutile phase led to increased hardness values of TiO\({}_{2}\) coatings were demonstrated by [PERSON] et al. [36] and [PERSON] and his colleagues [37]. The hardness values steadily rise as the rutile-to-anatase ratio rises in \(-\)50 and \(-\)75 V biased samples. The copper addition, grain refinement, and lattice microstrain increase as the bias voltage rises also contribute to the substantial increase in the hardness values. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**Phase/Plane**} & \multirow{2}{*}{\begin{tabular}{c} **FWHM,** \\ **(Degree)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Grain Size,** \\ **(nm)** \\ \end{tabular} } & \multicolumn{2}{c}{**Dislocation**} & \multirow{2}{*}{**Micro-Strain**} & \multirow{2}{*}{\
\begin{tabular}{c} **W\({}_{\text{ntitle}}\)** \\ **\%** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **W\({}_{\text{natase}}\)**,** \\ **\%** \\ \end{tabular} } \\ \hline \(-\)25 V & Anatase (101) & 0.8373 & 9.72 & 10.58 & 0.016 & 0 & 100 \\ \(-\)50 V & Anatase (101) & 0.9848 & 8.26 & 14.65 & 0.019 & 14.6 & 85.4 \\ \(-\)75 V & Anatase (101) & 1.0630 & 7.66 & 17.05 & 0.021 & 21.3 & 78.7 \\ \(-\)100 V & Rutile (110) & 1.4622 & 5.60 & 31.93 & 0.026 & 100 & 0 \\ \hline \end{tabular}
\end{table} 
Table 2: Calculated parameters from anatase (101) and rutile (110) maximums, together with anatase and rutile percentage. When examined independently, it can be challenging to determine a relationship between a coating's tribological characteristics and its hardness. For that reason, scratch tests were conducted. Adhesion should rise due to the greater displacement brought on by the higher ion velocity at higher bias voltages [38]. The scratch test results indicate that with a bias increase up to \(-75\) V, the critical loads increase from about 8 up to over 50 N (Table 3). Along the scratch track of both films deposited at \(-50\) and \(-75\) V, there was evidence of lateral chipping and the coatings' adhesive disintegrations parallel to the scratch direction (Figure 7). The film attempts to conform to the substrate's plastic deformation that causes these cracks to emerge. However, cohesive failure can offset any increased adhesion that may exist between the film and the Ti6 Al4V alloy. This is the most plausible reason why the \(-100\) V sample's partial delamination occurred at the lowest L\({}_{\text{c}}\) values (about 5 N). These findings appear to support the microstructure and phase analysis, which reveals a high-quality anatase phase and anatase-rutile mixture while rutile has poor crystallinity and increased lattice microstrain. The implants are often in direct contact with dense cortical and porous trabecular bone and their surface endurance to friction and abrasion are also important.