Voltammetric and chronoamperometric studies of silver electrodeposition from a bath containing HEDTA |
| |
Authors: | G M de Oliveira M R Silva Ivani Aparecida Carlos |
| |
Affiliation: | 1.Departamento de Química,Universidade Federal de S?o Carlos,Sao Carlos,Brazil |
| |
Abstract: | The electrodeposition of silver on platinum from ammonium-buffered solutions containing HEDTA (N-(2-hydroxyethyl)ethylenediaminetriacetic
acid) at various concentrations was investigated. Potentiometric titration and voltammetric studies indicated that in the
presence of 2.0 × 10−1 M HEDTA, the deposited silver was reduced from a mixture of AgHEDTA]2− and Ag(NH3)2]+ complexes, whereas at 2.0 × 10−2 M and 2.0 × 10−3 M HEDTA in the electrolyte, the silver was reduced from the Ag(NH3)2]+ complexes alone. Hydrodynamic studies showed variation in the diffusion coefficient for the electroactive species in solution,
depending on the HEDTA concentration. Chronoamperometric study in a solution containing 2.0 × 10−1 M HEDTA at low overpotential (0.000 V to –0.050 V) showed a transition from progressive to instantaneous nucleation in a single
current transient, whereas, at −0.200 V only 3D-progressive nucleation controlled by mass transport was observed. Scanning electron microscope images showed that the silver
films produced in silver baths with HEDTA were uniform, without cracks, and fine-grained, regardless of its concentration,
while in the absence of HEDTA the morphology was rough and dendritic. X-ray diffraction analysis of the films obtained at
various HEDTA concentrations revealed polycrystalline silver, similar to film obtained in cyanide and EDTA/ammonia baths. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|