open access

https://hdl.handle.net/2115/80139

Characterization of Dark-Colored Nanoporous Anodic Films on Zinc

英語

dark-colored film

2020-11

MDPI

Coatings

10(11)

1014

In this study, zinc is anodized at different voltages in 0.1 mol center dot dm(-3) KOH electrolyte to form nanoporous anodic films. Dark-colored anodic films are formed at anodizing voltages <= 6 V, whereas colorless anodic films are developed at voltages >= 7 V. The anodic films formed at all voltages consist of crystalline ZnO, which was identified by X-ray diffraction and Raman spectroscopy. The Raman spectra of the dark-colored anodic films show the enhanced intensity of the LO phonon mode due to electric-field-induced Raman scattering, which may be associated with the presence of metallic Zn nanoparticles in the anodic films. Scanning electron micrographs and transmission electron micrographs of the cross-section of the dark-colored anodized zinc reveal the formation of two-layer porous anodic films with a highly rough metal/film interface. In contrast, nanoporous anodic films of uniform thickness with a relatively flat metal/film interface are formed for the colorless anodized zinc. The transmission electron microscopy (TEM)/energy dispersive X-ray spectroscopy (EDS) analysis suggested the presence of zinc nanoparticles in the dark-colored anodic films. The non-uniform anodizing and the formation of metal-nanoparticle-dispersed porous anodic films cause the formation of dark-colored anodic films on zinc.

学術雑誌論文

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