Abstract:
Bi nanocrystalline films were formed from perchlorate electrolyte (PE) on Cu substrate via
electrochemical deposition with different duration and current densities. The microstructural,
morphological properties, and elemental composition were studied using scanning electron
microscopy (SEM), atomic force microscopy (AFM), and energy-dispersive X-ray microanalysis
(EDX). The optimal range of current densities for Bi electrodeposition in PE using polarization
measurements was demonstrated. For the first time, it was shown and explained why, with a
deposition duration of 1 s, co-deposition of Pb and Bi occurs. The correlation between synthesis
conditions and chemical composition and microstructure for Bi films was discussed. The analysis of
the microstructure evolution revealed the changing mechanism of the films’ growth from pillar-like
(for Pb-rich phase) to layered granular form (for Bi) with deposition duration rising. This abnormal
behavior is explained by the appearance of a strong Bi growth texture and coalescence effects.
The investigations of porosity showed that Bi films have a closely-packed microstructure. The main
stages and the growth mechanism of Bi films in the galvanostatic regime in PE with a deposition
duration of 1–30 s are proposed.
