Biomedical Engineering Reference
In-Depth Information
induced by the thermal expansion mismatch between HA and Ti. The
K
c
value achieved for
the pure Ti was close to the highest value obtained for the Ti alloys in our research [Onoki et
al. 2003]. The fracture appearance in Fig.5 may suggest that the interface toughness should
be equal or higher than that of the HA ceramics only. While further development is needed
to improve the fracture property of the solidified HA, the HHP treatment may have the
advantage over the plasma-spraying technique in the preparation of thermodynamically
stable HA without decomposition. The above results demonstrate the usefulness of the HHP
method for bonding HA and Ti in order to produce a bioactive layer in biomaterials.
Fig. 4. Photograph of the bonded body of HA ceramics and Ti metal (20mm in diameter).
Pre-crack
Fig. 5. Photograph of the fracture surface in a HA/Ti specimen after 3point bending test.
Note that the crack propagated into HA.
