Mg alloys in vitro degradation in simulated body fluid and citrate solutions

In recent years new class of biodegradable metal emerges as an alternative for biomedical implants. There are three metals (Iron, Zink and Magnesium) considered as the basis of biodegradable materials for medical application. Degradation of Mg under the physiological conditions avoids reoperation to remove bone implant, but still they didn't become the optimal material controlling biodegradation and tailoring alloy composition and microstructure depending on texture, grain size, manufacturing method and post-processing techniques. The purpose of this research was assessment of physical and chemical characteristics of Mg alloys in different environments that simulated natural. Mg alloys with the addition of Zr(0,65%), Al(1,85%) and Nd(1,25%) were used in experiment. Static and dynamic degradation in Simulated Body Fluid and citrate buffer were used to determine alloy corrosion properties. The pH value of the solution was recorded after immersion tests every 3, 6, 18 and 24 hours. Surface morphology before and after emersion tests was observed using a scanning electronic microscope. Plastic deformation of Mg alloy (Mg-Zr(0,65%)-Al(1,85%)-Nd(1,25%) coused fast degradaion with significant pH change during the static immersion test in SBF and citrate buffer. We considered less hydrogen output from as cast and temperature processing alloy both in static and dynamic degradation test that alloy to select these materials for in-vivo experiment. Olso we determined different mechanisms of alloy corrosion-SBF solution causes the intercrystalline corrosion, while citrate solution caused local corrosion.