Structure and shielding properties of the unsupported Bi films electrodeposited in galvanostatic and pulse regimes

Bi-unsupported films were fabricated via the electrochemical deposition method at different values of current density in two technological regimes: galvanostatic (GSR) and pulse (PR). It was observed that the unsupported Bi films obtained in GSR exhibited a granular structure. With increasing current density from 10 to 20 mA/cm², there is a rise in the Bi grains' size, possibly due to their coalescence. In contrast, the films produced in the PR regime exhibit a fine-grained structure. The chemical composition study demonstrated that there are no interfering phases in the obtained films. Statistical analysis of the most probable grain size showed that the unsupported Bi films' grain size varied from 10.5 to 14.8 μm with increasing current density for the GSR. The grain size of the films received in the PR is 4.5 μm. The relation between the Bi-unsupported films’ synthesis regimes and the crystal structure is determined. It has been shown that the presence of crystallographic texture correlates with scanning electron microscopy results. Due to the fact that the information about pure Bi-unsupported films obtained via pulse electrodeposition is almost absent in the literature, this study will increase awareness on this topic. The gamma-radiation shielding effectiveness was determined using Phy-X/PSD software and a Co⁶⁰ gamma-quanta source. As a result of the comparison of the obtained parameters, a slight discrepancy between them and Pb was found. Due to the high toxicity of Pb, Bi-based materials with environmentally friendly properties may represent an outstanding choice for use as perspective materials for radiation shielding applications.