Electrochemical deposition regimes and critical influence of organic additives on the structure of Bi films

Abstract

The electrodeposition of Bi films from an acid perchlorate electrolyte was examined. The influence of various factors on the process of bismuth electrodeposition was investigated. It was determined that electrolyte mixing, temperature, organic additives exert a noticeable influence on the electrode process of the discharge of Bi3+ions in acid perchlorate electrolyte. X-ray diffraction patterns for all samples were indexed to rhombohedral Bi. Coatings with a signified texture (012) are formed in electrolyte without additives. This texture is retained by adding into the electrolyte the organic additives such as cresol, resorcinol, synthanol. With coloring agents (acridine yellow and safranin violet), the growth texture changes and the most intense reflex becomes (110). SEM investigations of coatings surface morphology showed that films electrodeposited without additives, as well as with safranin coloring agent, eventually form crystalline films with a block size of tens of microns, but with different texture growth. The additional presence of such organic additives as syntanol and resorcinol in the electrolyte guarantees flat, dense, close grained and uniform coatings with a thickness of 600 μm at room temperature and the highest cathode current density.