Biomedical Engineering Reference
In-Depth Information
debris particles is the wear process and grit blast, which includes
Al
2
O
3
, ZrO
2
, or SiO
2
particles on the surfaces of especially treated
implants.
An appropriate surface modiication would prevent their transfer
into nearby tissues. The absence of debris particle generation is
crucial for the prevention of implant malfunction. The determination
of the mechanisms of debris generation and appreciate modiication
of implant surface bulk structure and properties is one of the
main aims of current research projects.
The main purpose of current research is to prevent the failures
caused by infection by changing the biomaterial's properties and
making them highly friendly for surrounding tissues.
Ti and Ti-based alloys are preferred materials in the production
of implants in both medical and dental applications. These
biomaterials have relatively poor tribological properties because
of their low hardness. One of the methods that allow the change
of biological properties of Ti alloys is the modiication of its
chemical composition. The other way is to produce a composite
that will exhibit the favorable mechanical properties of titanium
and excellent biocompatibility and bioactivity of ceramic. The most
commonly used ceramics employed in medicine are hydroxyapatite
(HA), silica, and bioglass. HA shows good biocompatibility because
of its similar chemical and crystallographic structure to the apatite
of living bone. The ceramic coating on the titanium improves the
surface bioactivity but often lakes off as a result of poor ceramic/
metal interface bonding, which may cause the surgery to fail. For this
reason, composite materials containing titanium and ceramic as a
reinforced phase are expected to have broad practical applications.
Since 1996 a research program was initiated at the Institute of
Materials Science and Engineering, Poznan University of Technology,
in which ine grained, intermetallic compounds were produced
by mechanical alloying, high-energy ball milling, hydrogenation-
disproportionation-desorption-recombination (HDDR), or mechano-
chemical processing (MCP) [22−28, 34−36]. The mechanical synthesis
of nanopowders and their subsequent consolidation is an example
how this idea can be realized in metals by a so-called bottom-up
approach. On the other hand, other methods have been developed,
which are based on the concept of the production of nanomaterials
from conventional bulk materials via the top-down approach. The
investigations by severe plastic deformation (e.g., cyclic extrusion
