Effect of Pulse Current Density on Gold Nanograin Growth in Sulfite Electrolyte-Based Electrochemical Deposition

This study presents the effect of pulse current density on gold nanograin growth and the macro mechanical characteristic of gold films deposited in non-cyanide sulfite bath. By tuning the density of pulse current to change its corresponding overpotential, the nucleation and growth of gold grains on the cathode surface were simultaneously modulated, resulting in variations in grain size and distinct morphology. The characterization results show that, with the appropriate current density, the overpotential was well distributed to nucleation and grain growth, forming single-crystalline gold coatings with embedded defects. The orientation of gold grains was effectively controlled along <;111> direction. Further the nanoindentation measurement shows the correlation of mechanical property and microtexture, revealing the grain growth kinetics in sulfite electrolyte-based electrochemical deposition.