Biomedical Engineering Reference
In-Depth Information
i
et al
. [11] investigated formation mechanism of self
organized TiO
2
nanotube arrays prepared by anodic oxidization
of the pure titanium in electrolyte containing potassium luoride
and sulfate. They investigated anode mass, current density, and
surface topography changes during the anodization. They found
that with the protection of the oxide layer, long nanotubes could
be formed in electrolyte solutions with relatively high pH [11].
Figure 9.53 shows an example of the anodic current density, the
mass lost in anode, and the surface morphology during the
anodization in moderately acidic electrolytes (pH 2.8). The time-
dependent anodic current density, especially during the irst minutes
characterized the property of the electrolyte. The anodization
results in a fast drop, followed by a small increase, and then slow
decrease in current density [11]. The anodization can be divided into
three stages:
Figure 9.53
Anodization of titanium in pH 2.8 electrolyte. The plots
show the anodic current density and the loss in anode mass
during the anodization, respectively. The SEM images show
the surface morphology of the samples anodized at different
times as marked on the
I
-
t
plot [11].
(i) The electrochemical oxidization of titanium surface that
corresponds to the irst current drop
(ii) The nanotube formation that corresponds to the current
increase
