resumo
This work reports a new methodology to measure quasi-simultaneously the local electric fields and the distribution of specific ions in a solution via selective microelectrodes. The field produced by the net electric current was detected using the scanning vibrating electrode technique (SVET) with quasi-simultaneous measurements of pH with an ion-selective microelectrode (pH-SME). The measurements were performed in a validation cell providing a 48 mu m diameter Pt wire cross section as a source of electric current. A time lag between acquiring each current density and pH data-point was 1.5 s due to the response time of pH-SME. The quasi-simultaneous SVET-pH measurements that correlate electrochemical oxidation-reduction processes with acid-base chemical equilibria are reported for the first time. No cross-talk between the vibrating microelectrode and the ion-selective microelectrode could be detected under given experimental conditions. (C) 2010 Elsevier B.V. All rights reserved.
palavras-chave
CORROSION PROTECTION; GALVANIZED STEEL; CUT EDGE; SVET; MICROSCOPY; COMPOSITES; ALUMINUM; ALLOY
categoria
Electrochemistry
autores
Lamaka, SV; Taryba, M; Montemor, MF; Isaacs, HS; Ferreira, MGS
nossos autores
Mário Guerreiro Silva Ferreira
Professor(a) Jubilado(a)agradecimentos
The financial support of the Portuguese FCT, through projects PTDC/CTM/65632/2006 and PTDC/CTM/108446/2008 is gratefully acknowledged. Work of HSI was assisted by the U.S. Department of Energy, Divisions of Chemical and Material Sciences under the Contract No. DE-AC02-98CH10886. Advice and maintenance of the SVET/SIET system by Alan M. Shipley of Applicable Electronics is also acknowledged.