Fig. 3 shows the backscatter electron images of samples
deuterated at 900 C, 800 C and 700 C. It can be seen from Fig. 3(a)
that, when deuterated at 900 C, the sample is in good condition
and only a few cracks appear on its edge. However, when deuterated
at 800 C, the sample cracks seriously, with the cracks intersecting
each other in a disordered way and forming a net-shaped
morphology, as shown in Fig. 3(b). When deuterated at 700 C, the
sample also cracks seriously like that at 800 C, see Fig. 3(c), but the
sizes of the cracks become much smaller and their density becomes
much greater than those at 800 C.
The XRD results of samples deuterated 900 C, 800 C and
700 C are shown in Fig. 4. It can been seen that all the samples
deuterated at 900 C, 800 C and 700 C have a ε-ZrD1.8 phase. It
should be noted that these results only represent the phase structure
at the surface, not the inner part, because of limited X-ray
penetration ability (~30 mm) on the bulk samples.