Mechanical properties and in-vitro corrosion behaviour of Mg-6Zn/bioactive glass composite
Loading...
Date
2017-06
Authors
Wong, Kae Yuan
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Biodegradable magnesium and its alloys are widely used as potential orthopedic bone implant materials due to their good biocompatibility in the bio-environment. To improve the mechanical properties and in-vitro corrosion behaviour of biodegradable magnesium, magnesium-zinc matrix reinforced with different weight percentage (0, 5, 10, 15 wt.%) of bioglass (45S5) were fabricated using powder metallurgy technique in this research work. The composites were compacted under pressure 300 MPa and were sintered at 350°C. Microstructure of composites was observed using an optical microscope. Density was determined using a gas pycnometer. The mechanical properties such as microhardness and compressive strength were studied. Corrosion rate was investigated by immersion test. Density (1.845 - 1.958 g/cm3) of sintered composites are close to the density value of natural bone (1.8 - 2.1 g/cm3). All composites show improvement in microhardness and compressive strength if compared to the naked Mg-6Zn alloy. Mg-6Zn/5BG shows the highest microhardness value (67.21 HV) and compressive strength (169MPa). Agglomeration of bioglass particles has been seen on the microstructure of composites with 10 wt.% and 15 wt.% of bioglass content. In-vitro corrosion test shows that Mg-6Zn/5BG has the lowest corrosion rate which is 0.154 mm/year. However, composites that have porosity of more than 7.0% (Mg-6Zn/10BG and Mg-6Zn/15BG) will have adverse effect on corrosion resistance. The addition of bioglass to the Mg-6Zn has also improved the formation of apatite layer after soaking in SBF solution.