Microstructure and Degradation Mechanism of Biodegradable Low Alloyed Mg-Zn-Ca Alloys in Glucose Containing Physiological Solution

Recently, magnesium (Mg) and its alloys have been considered as biodegradable implant materials due to their excellent physical properties (similar to those of bone), excellent biocompatibility, and low densities compared to other metallic implant materials. However, Mg alloys have a rather high corrosive nature. The rapid degradation and the mass production of hydrogen gas (as a result of cathodic reaction) of Mg alloys can lead to mechanical instability during the bone healing process. Therefore, before Mg implants can be used in applications, it is necessary to implement strategies to improve its mechanical and corrosion resistance. For example, it is necessary to carefully select bio-friendly alloying elements, such as Zn and Ca, that can enhance not only the the mechanical properties but also the corrosion properties of the alloy. Furthermore, post-treatment, such as heat treatment, provides an effective way to delay the deterioration process in Mg alloys. In addition, both the inorganic and organic components of the physiological solution can also affect the degradation rate of the bioimplant alloy. Nevertheless, the effect of glucose on the degradation behaviour of Mg-Zn-Ca alloys is not yet understood. Therefore, in this thesis, the influence of microstructure, heat treatment, and glucose in a physiological solution on the degradation mechanism of Mg-Zn-Ca alloys are investigated.