Electrodeposition of gold in ammoniacal medium: influence of substrate and temperature

The role of temperature in copper electrocrystallization in ammonia–chloride solutions

“…At similar overpotential, the nucleation rate increases with the increment in temperature. It is interesting to observe that the diffusion coefficient is greater at 323 K, suggesting that the diffusion of the chemical species in solution is favored with the temperature, similar to reported by others authors [1][2][3]5]. Likewise, this result agrees with the predicted by Hirschfelder et al [34] and Einstein-Stoke's equations [13].…”

“…However, a contrary behavior has been observed [1][2][3][4][5], which is probably because the value of the surface energy (σ) leads to a slight increase with increasing temperature (dσ/dT ∼ (0.06-0.16) × 10 −3 J/m 2 K) regardless of the method of estimating the kinetic barrier [7][8][9][10][11]. Moreover, if one take in account a possible curvature (or nucleus size) dependence of the surface tension (the specific surface energy, estimated from nucleation rate data, refers to nuclei of critical size) [6].…”

“…Although, the effect of temperature is well known, only few studies have been reported about this factor effect [1][2][3][4][5]. Such studies indicate that nucleation and growth rate increase with the temperature, which could intrinsically suggests a diminution of energy requirement for the electrodeposition process.…”

Black nickel electrodeposition from a modified Watts bath

“…For this purpose, a series of current-time transients at a given deposition potential, for black nickel deposition from the modified Watts bath was measured and some representative data are given in Figure 6. The decrease in current in the initial stages of the transients is related to double layer charging [18]. Then the current rises to a steady-state value for a given potential, which is determined by diffusion.…”

Electroformed objects for jewelry: secondary ion mass spectrometry characterization of Au films from CN-free electrolytes

“…In recent years some studies have been carried out, in order to formulate electroforming baths with different Au complexes and electrolytes. At the present time, complexes based on sulfite, 1,2 thiosulfate 3-5 or amines 6 are considered promising alternatives, moreover they exhibit good stability constants, suitable redox potential 7,8 and good throwing power. 9 Nevertheless, the use of these complexes is not common in jewelry electroforming production because their syntheses are laborious and the baths need stabilizers and/or brightners that raise the electrolyte service life and promote suitable film growth.…”