TiCl 4 þ CCl 4 þ 8Na ƒƒƒ!
450
C TiC þ 8NaCl
ð19Þ
The XRD pattern (Figure 7.18(a)) indicates that the obtained sample is cubic phase
TiC, with cell constant a ¼ 4:34 A ˚ . TEM imaging (Figure 7.18(b)) reveals that it
consists of nanoparticles of size 10–20 nm [67]. The co-reduction carburization
method may be used to prepare other transition metal carbides. For example, as
shown in Reaction (20), nanocrystalline ZrC, size 10–25 nm was synthesized on
heating at 550
C for 12 h [68].
ZrCl 4 þ CCl 4 þ 8Na ƒƒƒ!
550
C ZrC þ 8NaCl
ð20Þ
When carbon was used instead of CCl 4 , 8–12 nm nanocrystalline TiC was also
obtained at 650
C [69].
Fig. 7.17. (a) and (b) TEM images of SiC nanowires prepared by sodium co-reduction of SiCl 4
and CCl 4 at 400
C, (c) TEM image of a straight
single SiC nanowire and (insert) its ED pattern,
and (d) TEM image, and (insert) its ED pattern,
of a tubular-like or hollow-structure SiC nanowire prepared by sodium reduction of CCl 4 in
the presence of silicon powders at 700
C.
7.3 Synthesis of Diamond, Carbon Nanotubes and Carbides 185