Biomimetic Interfaces of Plasma- Modified Titanium Alloy - Biomimetic Architectures by Plasma Processing - page 215

Figure 6.34 XRD patterns of titanium implanted with Ca + (195 kV, 5

×

10 17

−

): (a) As-implanted; (b) Annealed 775 K/1 h in Ar; (c)
Annealed 775 K/3 h in Ar. Reprinted from Ref. [65], Copyright
1999, with permission from Elsevier.

cm

2

coatings are often used to improve the
surface corrosion resistance, suppress the release of toxic metallic
ions, and enhance the biocompatibility of biomedical metallic
materials. However, this coating is generally bio-inert. Liu et al.
successfully produced a bioactive nanostructured TiO

Plasma-sprayed TiO 2

surface on
titanium by combining plasma spraying and hydrogen PIII [10]. The
hydrogen PIII nano-TiO

2

coating induced bone-like apatite formation
on the surface after immersion in SBF (Fig. 6.35). In contrast, apatite
could not form on either the as-sprayed TiO

2

surface (both <50
nm grain size and >50 nm grain size) or hydrogen-implanted TiO

2

with a grain size larger than 50 nm. During the combined process,
hydrogen ions reacted with oxygen on the surface to form Ti-OH
bonds and induced the formation of a hydrogenated surface on the
plasma sprayed TiO

2

. After incubation in SBF, Ti-OH reacted with
the hydroxyl ions in the SBF to produce a negatively charged surface
with the functional group Ti-O as:

2

−

→

−

O
Deposition of calcium ions played a key role in apatite nucleation
in an ionic solution. Formation of a negatively charged surface led to

Ti-OH + OH Ti-O + H 2