title: All-Diamond Microelectrodes as Solid State Probes for Localized Electrochemical Sensing.
abstract: 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.
authors.affiliation: †CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Eduardo L
authors.initials: EL
authors.lastname: Silva
authors.affiliation: §Materials Metrology Division, INMETRO, 25250-020, Duque de Caxias, Rio de Janeiro, Brazil.
authors.forename: Cristol P
authors.initials: CP
authors.lastname: Gouvêa
authors.affiliation: †CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Marcela C
authors.initials: MC
authors.lastname: Quevedo
authors.affiliation: †CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Neto
authors.affiliation: §Materials Metrology Division, INMETRO, 25250-020, Duque de Caxias, Rio de Janeiro, Brazil.
authors.forename: Braulio S
authors.initials: BS
authors.lastname: Archanjo
authors.affiliation: ‡I3N, Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: António J S
authors.initials: AJ
authors.lastname: Fernandes
authors.affiliation: §Materials Metrology Division, INMETRO, 25250-020, Duque de Caxias, Rio de Janeiro, Brazil.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Achete
authors.affiliation: †CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Rui F
authors.initials: RF
authors.lastname: Silva
authors.affiliation: †CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.|⊥MagIC, Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck Str. 1, 21502 Geesthacht, Germany.
authors.forename: Mikhail L
authors.initials: ML
authors.lastname: Zheludkevich
authors.affiliation: †CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Filipe J
authors.initials: FJ
authors.lastname: Oliveira
mesh_terms: D018130:Diamond; D055664:Electrochemical Techniques / Q000295:instrumentation*; D008839:Microelectrodes; D015335:Molecular Probes
chemical_list: D015335:Molecular Probes; D018130:Diamond