## 3 Electrodeposition
### Electrolytes
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c c c c c c c} \hline \hline
**Bath Type** & **Al** & **Bi** & **Cr** & **Co** & **Cu** & **Fe** & **Mn** & **Mo*** & **Ni** & **P** & **Pd** & **Pt** & **Re*** & **Ti** & **W*** & **V*** & **Zn** & **Ref.** \\ \hline \hline sulfate-citrate-ovations * & & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride-sulfate-citrate-ovations * & & & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride-sulfate-citrate-ovations * & & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride-sulfate-citrate & & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride-sulfate-citrate & & & & & & & & & & & & & & & & & & & & & \\ \hline sulfate-citrate & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride-sulfate-citrate & & & & & & & & & & & & & & & & & & & & & \\ \hline sulfate–citrate & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride-sulfate & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride-oxylations * & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride & & & & & & & & & & & & & & & & & & & & & \\ \hline sulfate-citrate-ovations * & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride-citrate-ovations * & & & & & & & & & & & & & & & & & & & & & \\ \hline chloride-DMF-AN & & & & & & & & & & & & & & & & & & & & \\ \hline chloride–nitrate(Bi)–DMF-AN & & & & & & & & & & & & & & & & & & & \\ \hline chloride–nitrate(Co)–DMSO-AN & & & & & & & & & & & & & & & & & & & & \\ \hline chloride–glycerin & & & & & & & & & & & & & & & & & & & & \\ \hline \hline \end{tabular}  
* Metal as oxygen in solution.  
\end{table} 
Table 1: Types of aqueous and organic baths used for electrodeposition of HEAs. [PERSON] et al. [35] investigated the effect of WO4\({}^{2-}\) and MoO4\({}^{2-}\) concentrations in a sulfate-citrate bath on the composition of NiFeCoMoW alloys. They observed competitive behavior between these two metals, with increasing oxyanion concentrations leading to a decrease in current efficiency (from 42 to 45% to 20 to 25%), an effect more pronounced in the case of molybdenum species. These coatings exhibited banded structures containing nanoglass boundaries that extended throughout the bulk and were elongated in the direction of growth [35; 66]. Further studies [22] showed that increasing the pH from 5 to 7 led to only a slight increase in the Mo (from 14 to 16 at%) and W (from 11 to 12 at%) contents in the alloys, accompanied by a drastic decrease in the cobalt content (from 31 to 15 at%). The concentrations of iron (30-46 at%) and nickel (6-16 at%) were more variable, although both elements appeared to vary inversely within the coating. [PERSON] and [PERSON] [33] systematically analyzed the codeposition of FeCoNiCuW alloys from alkaline sulfate-citrate-oxyanion baths under galvanostatic conditions. In an unusual approach, they used ferric instead of ferrous salt to improve the stability of iron ions against oxidation. However, this solution may have resulted in very low current efficiencies for alloy deposition, reaching only about 8%. Compact alloy with similar element concentrations Fe20 Co19 Ni17 Cu19W24 was obtained. It was observed that the presence of copper ions in the bath catalyzed the deposition of the other metals, particularly tungsten and iron. However, the codeposition mechanism was not explained. [PERSON] et al. [52] investigated the role of citrate ions (added as sodium salt and citric acid) and the cationic surfactant cetyltrimethylammonium bromide CTAB on the potentiostatic electrodeposition of FeNiCoCrMn alloys from a chloride-based electrolyte (pH 3.5). Single-phase alloys with a face-centered cubic structure were obtained, but their elemental composition did not show a clear dependence on the presence of additives or the applied potential. Nevertheless, it was observed that both additives influenced the surface texture of the deposits: CTAB promoted a rough and irregular surface, while the presence of citrate resulted in smooth and uniform crystalline films.