Mg/Zn COMPOSITES PRODUCED BY MECHANICAL ALLOYING AND HOT PRESSING AND IN-VITRO BIODEGRADATION

Year 2019, Volume: 2 Issue: 1, 22 - 38, 30.06.2019

Simay Erdibil , Serap Cesur Rasim İpek

Abstract

Biodegradable
implants have many advantages over conventional steel and titanium based
implants. Most important one of these advantages is the ability of these
implants to degrade within a desired span of time (compatible with tissue and
bone growth) after their function is over, without giving any harm to the body.
The aim of this study is to develop a magnesium based biodegradable implant to
be used as a bone plate. Mechanical and physical properties of Mg alloys that
should possess for these applications are almost completely established,
whereas the applicability still has to be investigated. In this study, Mg/MgZn/Zn composites were produced by mechanical alloying
and hot pressing. Biodegradability of Mg/MgZn/Zn composites was tested
as in-vitro in simulated body fluid (SBF) solution. SBF is nearly equal to
human body blood plasma with ion concentrations. Seven implants were produced.
They were placed in SBF solution and then their corrosion resistances were
followed. During the process, visual changes of the implants
were observed, pH, Mg ion concentrations of SBF solutions and mass, dimensional
changes of degraded implants in solutions were measured. As soon as, implants
were placed in SBF solutions, gas outlet of H₂ was observed, because
of Redox reaction, which took place between implants and SBF. The composites in SBF
remained between 1-360 hours and Zn% 2.35 and 3.10 had the longest degradation
time when compared to others. Therefore, only three of the composites Zn% 0 (7h),
2.35 (360h) and 3.10 (192h) were selected for further, SEM and mechanical
control tests.

Keywords

Magnesium, Zinc, MgZn composites, biodegradable implants, SBF

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