Biomedical Engineering Reference
In-Depth Information
a
b
Ti
V
C
O
Ca
Al
P
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Energy/keV
c
d
Ca
P
Ti
O
V
Ca
Al
C
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Energy/keV
Fig. 3.15
SEM micrographs and EDX spectra of the worn surfaces of the TC4 ball [
35
]: (
a
) SEM,
1,000 cycles; (
b
) EDX, 1,000 cycles; (
c
) SEM, 5,000 cycles; (
d
) EDX, 5,000 cycles
increase of test cycles, and then delamination on a fraction of the enamel surface
happens, resulting in a large increase in the width of wear scar. Subsequently, hard
and brittle enamel debris is attached to the contact interface and acts as a rigid abra-
sive. As a result, the wear process of enamel changes gradually from initial two-
body wear to three-body wear. This inference is also supported by the results of
SEM and EDX. The SEM micrographs showed that a few fl ake particles appeared
on the worn surface of enamel after 1,000 cycles (Fig.
3.11b
); they were mainly
composed of enamel debris (Fig.
3.12b
). Further SEM examinations on the cleaned
worn surface of enamel showed that most of the enamel rods presented signifi cant
deformation after 1,000 cycles (Fig.
3.14b
). Flake delamination occurred on the
enamel rods, and there existed some lacunae and much small debris around the rods
(Fig.
3.14c
). In addition, obvious ploughing and some enamel debris appeared on
the worn surface of the TC4 ball after 1,000 cycles, as shown in Fig.
3.15
.
The wear depth of enamel increased sharply with the number of cycles at the
early stage of wear, but it increased slowly after 2,000 cycles (Fig.
3.13
). The
ploughing effect became weak on the worn surface (Fig.
3.10
), and the profi les of
