resumo
A novel powerful pulsed discharge anodization technique has been applied to prepare dense, homogeneous oxide films of 16-180 nm thick on aluminum surface. The Volta potential difference (VPD) of the obtained films was studied by scanning Kelvin probe force microscopy. The VPD value was measured as a function of the film thickness and was compared with the similar dependences for the anodic alumina films prepared by the conventional galvanostatic and potentiostatic methods. The anodic films present polarization because of the embedded charges localized near the film interfaces. It was shown that despite the apparent differences in the respective anodization processes, the pulsed discharge films demonstrate the magnitude of polarization which is entirely comparable with that of the conventional anodic alumina films of the same thickness. At the same time, the pulsed discharge films are characterized by more uniform surface structure and electrical properties. The characteristic features of the films such as their fast growth and homogeneity have been considered in terms of the processes occurring at the powerful pulsed discharge.
palavras-chave
SCANNING KELVIN PROBE; FORCE MICROSCOPY; OXIDE-FILMS; CORROSION; POLARIZATION; MECHANISMS; KINETICS; COATINGS; BEHAVIOR; AA2024
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
autores
Lisenkov, AD; Salak, AN; Poznyak, SK; Zheludkevich, ML; Ferreira, MGS
nossos autores
Aleksey Lisenkov
Investigador
Andrei Salak
Investigador Principal
Mário Guerreiro Silva Ferreira
Professor(a) Jubilado(a)
Mikhail Zheludkevich
Investigador Principal Convidadoagradecimentos
Financial support of the Portuguese Foundation for Science and Technology (FCT-Portugal) through the project PTDC/CTM/72223/2006 is gratefully acknowledged.