| dc.description.abstract | In this study, bio-glass 45S5 powder was added into the mixture of Mg-Zn powders to
produce biocomposite using powder metallurgy method for biomedical applications. The
bio-glass composition was varied from 0, 5, 10, 15, 20, 25, to 30 wt. %. The objective of
this works is to study the effect of bio-glass addition into Mg-Zn based biomaterials in
terms of physical, mechanical, corrosion resistance and bioactivity properties. Optical
microscope, Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS)
and X-Ray Diffraction (XRD) were used to characterize the microstructure and phases
present in the composites. Microstructure result shows that bio-glass was distributed in the
matrix Mg-Zn. EDS results show that Zn has not completely diffuse into the Mg matrix due
to the effect of processing parameter. There is no evidence of bio-glass diffusion into the
matrix. XRD diffraction patterns of as sintered samples show expected peak of Mg in all
samples. Properties such as density and compressive strength were determined using the
pycnometer and Instron machine respectively. Density of the composite was compared with
the theoretical value and the result trends indicated that the density has increased as the
amount of bio-glass increased. The trends are valid for the true, theoretical, and bulk
densities. Increment of densities value could be subjected to the filling of interparticles
spacing by bio-glass. However, the total porosity also increased as the bio-glass amount
increased. It could be attributed to the segregation of bio-glass particles. As the amount of
bio-glass increase, more bio-glass segregate and leads to bigger size of bio-glass inclusion
size inside the composite. Since no reaction between magnesium and bio-glass, the bigger
the size of bio-glass inclusions, the larger the voids form at the interface, which will
eventually give raise to total porosity results. The compressive strength shows that as the
amount of bio-glass increased, the compressive strength of the composites decreased. This
also could be attributed to the voids left at the interface of bio-glass and matrix which acts
as crack initiators. In vitro test was conducted, in which samples were immersed in
Simulated Body Fluid (SBF) to determine the corrosion rate and bioactivity of the
composites. The results showed that corrosion rate of the samples decreases with increasing
content of bio-glass. The accumulation of corrosion products, alongside with the formation
of apatite layer retarded the corrosion process. The apatite layer that used to indicate the
bioactivity was also traced on the surface of composites. The apatite layer formed has a
lower value of Ca/P ratio compared to the ideal crystalline hydroxyapatite, however it is
still compliant with biomaterials requirement | en_US |
