改善鋁箔蝕孔密度與均勻性之電源波形設計
Date Issued
2005
Date
2005
Author(s)
DOI
932216E002020
Abstract
The effects of current waveforms and
sulfate ions on pitting behavior of aluminum
foils for low-voltage electrolytic capacitor were
investigated during etching in hydrochloric acid.
During the course of etching, the
galvanodynamic polarization curve was
recorded, in which the breakdown potential was
measured. A scanning electron microscope
was employed for characterizing the surface
morphology and cross section of the foil,
including the average depth and linear density
of the pits. Cross-sectional transmission
electron microscope specimens were prepared
from the as-etched foil to reveal the detailed pit
morphology and etch film structure. Finally,
X-ray photoelectron spectra of the surface film
on the as-etched foil were measured using an
ESCA250 (VG Science Inc., UK) spectrometer
with monochromatic Mg K radiation.
Experimental results indicate that
compared with the triangular and sinusoidal
waveforms, etching with the square current
waveform resulted in larger and deeper pits,
thicker etch films, and more weight lost during
etching. This is due to the more charge
imposed in each anodic half-cycle associated
with the square waveform. The presence of
sulfate ions in hydrochloric acid led to the
formation of finer, uniformly-distributed and
shallower pits; thereby, reducing the loss of
aluminum due to undermining by the cubic pits.
The effect of sulfate ions on the pitting
behavior was presumably due to competitive
adsorption of sulfate ions with chloride ions, as
shown by XPS analysis.
Subjects
galvanodynamic polarization curve
X-ray photoelectron spectra
competitive adsorption
aluminum foils for low-voltage electrolytic capacitor
Publisher
臺北市：國立臺灣大學材料科學與工程學系暨研究所
Type
report
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