Biomedical Engineering Reference
In-Depth Information
5.3
Corrosion of the Hydroxyapatite
Ti-Coated Compounds
Hydroxyapatite layers deposited on the Ti implant improve process
of the osseointegration and should keep or improve high corrosion
resistance of the applied metallic background.
J owi z
et al
. investigated corrosion resistance of the hydro-
xyapatite (HA) electrochemically deposited on different Ti-based
materials: micro-Ti [17], Ti-45S5 nanocomposites [19], and micro-/
nanocrystalline Ti-6Al-4V alloys [18]. For the HA deposition process,
they applied two different types of electrolytes. The source of Ca and
P states: 0.1M HCl + 0.005M HA and 0.042M Ca(NO
3
)
2
+ 0.025M
(NH
4
)
2
HPO
4
+ 0.1M HCl electrolytes (see chapter 9). The corrosion
resistance was investigated in Ringer's solution [17-19].
Corrosion potentiodynamic curves for Ti with HA deposits are
shown in Fig. 5.26 and Fig. 5.27 and corrosion data are summarized
in Table 5.8 [17].
Figure 5.26
Potentiodynamic corrosion curves for lat Ti (a), porous Ti
(b), lat Ti with calcium-phosphates (c), and porous Ti with
calcium-phosphates (d); (HA deposited using HA + HCl
electrolyte) [17].
Figure 5.27
Potentiodynamic corrosion curves for lat Ti (a) porous Ti
(b) lat Ti with calcium-phosphates (c) and porous Ti with
calcium-phosphates (d); (HA deposited using Ca(NO
3
)
2
+ (NH
4
)
2
HPO
4
+ HCl electrolyte) [17].
