To investigate the effect of halide ions on the electrodeposition behavior and morphology of copper powder, polarization curves were measured and constant current electrolysis of 300 and 500 A·m-2was conducted in an electrolytic solution containing 0.079 mol·dm-3Cu2+and 0.5 mol·dm-3free H2SO4 at 293 and 303K without stirring. Cl-promoted the deposition of copper powder, while Br-and I-suppressed deposition. The current efficiency for copper deposition increased with the addition of Cl-and decreased with the addition of Br-. The addition of Cl-reduced the average particle size of the copper powder and caused the dendrite-shaped branches and trunks to grow thinner and longer, resulting in a lower tap density. In contrast, the addition of Br-caused the average particle size, average crystallite size, and tap density of the copper powder to decrease. With increasing Cl-concentration, the current efficiency for copper deposition increased, that is, copper deposition was promoted. This even occurred in the region in which Cu2+ion diffusion was the rate-determining process, indicating that the deposition of copper powder was affected by the charge-transfer process. The change in the morphology of the copper powder with the addition of halide ions is attributed to the change in the charge-transfer process. The deposition of copper powder appears to proceed under a mixed rate-determining process involving the diffusion of Cu2+ions and charge transfer.
All Science Journal Classification (ASJC) codes
- General Materials Science
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering