Biomedical Engineering Reference
In-Depth Information
Table 5.9
Corrosion current
I
c
and corrosion potential
E
c
for the Ti-glass
nanocomposites: lat not etched, porous electrochemically
etched, and both lat and porous with deposited calcium-
phosphate (data taken from Figs. 5.28 and 5.29) [19]
I
c
(A/cm
2
)
Sample
E
c
(V)
Figure
5.10 × 10
-6
Ti-glass — not etched
-0.67 5.28a, 5.29a
7.32 × 10
-7
Ti-glass — not etched with
deposited HA
(0.1M HCl + 0.005M HA)
-0.8 5.28c
2.33 × 10
-7
Ti-glass — not etched with
deposited HA
(0.042M Ca(NO
3
)
2
+ 0.025M
(NH
4
)
2
HPO
4
+ 0.1M HCl)
-0.74 5.29c
1.86 × 10
-6
Ti-glass — etched 30 min
-0.55 5.28b, 5.29b
7.46 × 10
-7
Ti-glass — etched 30 min with
deposited HA
(0.1M HCl + 0.005M HA)
-0.86 5.28d
1.87 × 10
-6
Ti-glass — etched 30 min with
deposited HA
(0.042M Ca(NO
3
)
2
+ 0.025M
(NH
4
)
2
HPO
4
+ 0.1M HCl)
-0.54 5.29d
J owi z
et al
. [18] also investigated the HA deposited on
Ti-6Al-4V alloys. The corrosion properties of the lat (not etched),
porous and with HA deposited Ti-6Al-4V samples investigated
in Ringer's solution are shown in Fig. 5.30 and Table 5.10 [18].
Figure 5.30 shows examples polarization curves for micro and
nanocrystalline materials with deposited HA layer (see chapter 9).
The differences in corrosion properties are clearly visible (curves
a, c with comparison to b, d). The microcrystalline materials have
lower both corrosion current density and current density in the
passive range, with comparison to nanocrystalline materials. Best
corrosion resistance after electrochemical etching shows Ti (
I
c
=
2.52 × 10
-8
A/cm
2
).
