Fabrication of ti-40nb-10ha composite and ti-40nb alloy with surface nanotubes for implant application
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Date
2018-06
Authors
Chu, Chia Shin
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Abstract
The criteria of today’s biomaterials has included both physical properties and its
ability to promote growth of body tissue. In today’s technology, there are two methods to
improve bioactivity of the biomaterials are by adding bioactive materials such as
hydroxyapatite (HA) and surface modification of the materials. Hence, the mechanical
properties and bioactivity of Ti-40Nb-10HA composite was studied and the investigation
of the feasibility of forming nanotubes on Ti-40Nb alloy was also conducted. Ti-40Nb 10HA and Ti-40Nb was fabricated by powder metallurgy method with the compaction
pressure of 500 MPa. Ti-40Nb-10HA was sintered at variation of temperature (900°C –
1300 °C). Mechanical testings’ results show that the densification occurs when the
sintering temperature increases. The relative density of the sintered composite increases
as sintering temperature increases from 91.54% to 97.09%. The corrosion rates of the
sintered Ti-40Nb-10HA composite is within the range of 0.0348 to 0.1494 mm/year. The
modulus of the composite increase as the sintering temperature increase from 1000 °C to
1300 °C (17.6 GPa to 20.03 GPa) which is comparable with the modulus of human bone
which is 18GPa. The Ti-40Nb-10HA composite sintered at 1100°C to 1300 °C show
increasing micro hardness (112.46 HV to 183.85 HV) and compressive strength (159 MPa
to 193.33 MPa). In-vivo evaluation in HBSS for 7 days, nucleation and growth of apatite
increases as the sintering temperature increases from 1000°C to 1200°C while the surface
modification of Ti-Nb (sintered at 1200°C) exhibited formation of oxide nanotube with
reducing diameter from 70 nm to 50 nm when volume percentage of NH4F in electrolyte
increased from 0.5 vol% to 0.7 vol%