Electrodeposition of Cu-Sn Alloy from Oxalic Acid Electrolyte in the Presence of Amine-containing Surfactants

Method of potentiodynamic polarization was used to study the electrodeposition of a copper-tin alloy from an oxalic acid electrolyte with addition of 10⁻⁵–10⁻³ mol dm⁻³ of trimethyloctylammonium chloride, N-octylpyridinium bromide, and N-benzylpyridinium bromide. Introduction of these compounds changes the rate of the cathodic reduction of tin. It was found that the nature and concentration of the additives introduced into the electrolyte affects the composition, structure, glossiness, and roughness of the Cu-Sn coatings being formed. It was shown that introduction into an electrolyte of trimethylammonium chloride and N-octylpyridinium bromide inhibits the deposition of tin and favors formation of lustrous and semilustrous coatings containing 24.4–35.8 wt % tin. The presence of N-benzylpyridinium bromide in an oxalic acid electrolyte intensifies the cathodic reduction of tin and leads to formation of matte coatings containing up to 42.5 wt % tin.