Temperature effect on decorative gold coatings obtained from electrolyte based on mercaptotriazole - comparison with cyanide

Abstract

The aim of this work was to investigate the effect of temperature on the thickness, surface roughness, visual appearance and morphology of electrochemically deposited gold decorative coatings obtained from conventional cyanide electrolyte (AUROCIN DPB) and electrolyte based on mercaptotriazole (Au-MT). Heating of cyanide electrolyte does not significantly affect the thickness (b) of gold coatings (at 20 degrees C b = 0.08 mu m, at 30 degrees C b = 0.07 mu m and at 40 degrees C b = 0.08 mu m) and, for this reason, the decorative coating processes were carried out at room temperature. Temperature increase has a positive effect on thickness of decorative gold coatings obtained from electrolyte based on mercaptotriazole, but this effect is very small, so the heating of electrolyte is not recommended for this type of electrolyte (at 20 degrees C b = 0.08 mu m, at 40 degrees C b = 0.12 mu m and at 60 degrees C b = 0.13 mu m). The best coating roughness profiles are obtained at a temperature of 20 degrees C for both types of electrolyte. The morphology of gold deposits, obtained from both electrolytes, was studied using scanning electron microscopy.