resumo
The fabrication of an all-diamond microprobe is demonstrated for the first time. This ME (microelectrode) assembly consists of an inner boron doped diamond (BDD) layer and an outer undoped diamond layer. Both layers were grown on a sharp tungsten tip by chemical vapor deposition (CVD) in a stepwise manner within a single deposition run. BDD is a material with proven potential as an electrochemical sensor. Undoped CVD diamond is an insulating material with superior chemical stability in comparison to conventional insulators. Focused ion beam (FIB) cutting of the apex of the ME was used to expose an electroactive BDD disk. By cyclic voltammetry, the redox reaction of ferrocenemethanol was shown to take place at the BDD microdisk surface. In order to ensure that the outer layer was nonelectrically conductive, a diffusion barrier for boron atoms was established seeking the formation of boron hydrogen complexes at the interface between the doped and the undoped diamond layers. The applicability of the microelectrodes in localized corrosion was demonstrated by scanning amperometric measurements of oxygen distribution above an Al-Cu-CFRP (Carbon Fiber Reinforced Polymer) galvanic corrosion cell.
palavras-chave
DOPED DIAMOND; FABRICATION; ELECTRODES; ULTRAMICROELECTRODES; SEMICONDUCTOR; DEPOSITION; DIFFUSION
categoria
Chemistry
autores
Silva, EL; Gouvea, CP; Quevedo, MC; Neto, MA; Archanjo, BS; Fernandes, AJS; Achete, CA; Silva, RF; Zheludkevich, ML; Oliveira, FJ
nossos autores
Eduardo Luís Trindade da Silva
Bolseiro de pós-Doutoramento
Filipe José Alves de Oliveira
Investigador Principal
Marcela Citlalim Quevedo Reyes
Bolseiro de pós-Doutoramento
Miguel Ângelo da Costa Neto
Investigador Principal
Mikhail Zheludkevich
Investigador Principal Convidado
Rui Ramos Ferreira e Silva
Professor associadoProjectos
Corrosion adn corrosion protection in multi-material systems (PTDC/CTM/108446/2008)
Enhancing Scanning Ion-Selective Electrode Technique - SISET (SISET)
PROAIR - Active PROtection of multi-material assemblies for AIRcrafts (PROAIR)
agradecimentos
E. L. Silva would like to acknowledge FCT (Fundacao para a Ciencia e a Tecnologia) for the grant SFRH/BD/61675/2009. R. F. Silva acknowledges the research grant from CNPq