Corrosion studies on biodegradable magnesium alloys

• Main Author: Sia, Sheryl
• Other Authors: Tan Ming Jen
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/60994
• Institution: Nanyang Technological University

The world is facing an aging population and also there is an increase in war, and sports related injuries that people suffer from. Hence, there is a high demand in the need of hard tissue replacement such as bone. Existing metallic implants used consist of stainless steel, titanium alloys, as well as Co-based alloys. However, one major disadvantage of these metallic implants is the need for a second surgery for removal after damaged tissues are healed. Hence, another material is being investigated in order to eliminate the need for a second surgery which is magnesium and its alloys. Magnesium is found to be biodegradable in the human body and is beneficial as magnesium ions are one of the important components of the human body and it is mainly stored in bones. However, magnesium is found to be highly reactive and has insufficient mechanical properties for a bio-implant. To use magnesium as an implant material, element alloying is the one way to improve its mechanical properties. In this project, our aim is to find out the corrosion rate of magnesium alloys and its biodegradability is an attractive characteristic for bio-implants. Magnesium is a highly reactive metal, and corrosion rates in physiological solution are high. Therefore that is a need to control its corrosion rates for magnesium and its alloys to be suitable for orthopaedic purposes. Magnesium alloys would first require a bioactive calcium phosphate coating which will control its corrosion resistance. This coating will be done by using the hydrothermal deposition method. The corrosion resistance of magnesium and its alloys is then being investigated by using Simulated Body Fluid (SBF) solution to simulate physiological environment in an Immersion Test. Its corrosion rate is further investigated by adding albumin which makes solution even closer to the body fluid in human body. Characterisation of magnesium alloys such as the Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) will be done to examine the corrosion rate of magnesium alloys. Mass loss Method and Ion released method will also be used to further investigate the corrosion process of magnesium and its alloys.