Biomedical Engineering Reference
In-Depth Information
forming. It is important to note, that mechanical alloying technique
allows alloying of elements that are dificult or impossible to
combine by conventional melting methods. In general, the process
can be viewed as a means of assembling alloys constituents with a
controlled microstructure. At 1300°C, calcium is soluble in titanium
to the extent of at least 0.13% [23]. According to the Scherrer
method of XRD proiles, the mean crystallite size of heat treated
Ti-HA nanocomposites was 5-10 nm (Table 7.1).
Figure 7.4
XRD spectra of Ti and HA powders mechanically alloyed for
44 h and heat treated at 1150°C for 2 h under an argon
atmosphere: (a) Ti-3 vol% HA, (b) Ti-10 vol% HA and (c) Ti-20
vol% HA [23].
Table 7.1
Structural parameters and grain sizes for Ti-HA nano-
composites mechanically alloyed for 44 h and heat treated at
1150°C for 2 h in comparison with microcrystalline titanium
and hydroxyapatite
V
[Å
3
]
Sample
a
[Å]
c
[Å]
d
Ti-3 vol% HA
2.95
4.68
35.2
5 nm
Ti-10 vol% HA
2.98
4.76
36.6
6 nm
Ti-20 vol% HA
2.97
4.78
36.5 10 nm
Ti (microcrystalline)
2.95
4.68
35.3 45 μm
HA (microcrystalline)
9.42
6.87 527.9 10 μm
The effect of the initial composition on the phase composition
of microcrystalline Ti-HA composites was studied previously by
