Biomedical Engineering Reference
In-Depth Information
Fig. 9.1
Linearized Weibull plots of the fracture stresses measured in different test conditions in
inert atmosphere. Reprinted with permission of ASTM from [
279
], Fig. 2
specimen affects the value of
K
IC
[
36
,
278
,
279
]. Life is not simple for ceramists! A
setup for a 4-point bending test and ball head burst test is shown in Fig.
9.3
.
The design engineer is even better served by the knowledge of the stress inten-
sity factor, indicated in Fig.
9.2
by the log of crack propagation velocity extrapolated
to log of
K
I0
no crack propagation occurs. And there is more to learn
from Fig.
9.2
. It is a convincing illustration of the progress with respect to pure alu-
mina. It is rendered possible by the combining different compounds into composites,
compounds which compensate for each other's shortcomings.
Making ceramic objects.
Basically, the procedure for obtaining a ceramic object
did not change in the course of time. However for more complex systems such as
BIOLOX
R
delta (see below), a more complex flow sheet as shown in Fig.
9.4
is
followed.
5
The flow sheet is self-explaining.
Plastic surgery on alumina
. A convincing result of surgery on alumina is illus-
trated in Table
9.2
. Substantial improvement in bending strength and fracture
toughness is attributed to a tailored evolution in composition and particle size. The
ISO 6474-1 standard
Implants for surgery - Ceramic materials - Part 1: Ceramic
materials based on high purity alumina
(or its ASTM equivalent F 603) was released
in 1994. An ISO 6474-2 standard
Part-2: Composite materials based on a high
/
.Below
5
Our warm thanks to Dr.Meinhardt Kuntz, Bernard Masson and Dr.Thomas Pandorf (CeramTec,
Medical Products) who provided in preview their paper
Current State of the Art of the Ceramic
Composite Material BIOLOX
R
delta
. The authors permitted to use their data and comments.
