Fabrication and Characterization of Biodegradable Magnesium-Fluorapatite Nanocomposite Mehdi Razavi Mohammadhossein Fathi, Mahmood Meratian Department of Materials Engineering On January 2010 Language: Persian : Magnesium–based implants have the potential to serve as biocompatible, osteoconductive and biodegradable implants for load–bearing applications. These implants would be temporarily needed to provide mechanical support during the healing process of injured or pathological tissue. Moreover, the metallic implants, such as pins, screws, and plates used for repairing the bone defects, have to be removed by a second surgery after the bone was healed. Since, the repeated surgery will increase the morbidity and the health costs, then, the use of biodegradable metallic implants with a good biocompatibility is expected to overcome the limitations of conventional metallic biomaterials and remove the second surgery. In spite of the immense potential of biodegradable magnesium alloys, the fast biodegradation rates of magnesium–based implants in the physiological environments impose severe limitations in many clinical applications. If the implants being made of the magnesium alloys are used to repair the diseased bone tissue, they are possible to lose the mechanical stability before the healing of bone tissue due to the rapid biodegradation. Recently, some researches have been done to slow down the biodegradation rate of magnesium alloys. Besides improving the biodegradation rate of magnesium alloys, the biocompatibility should also be considered. Also, the mechanical properties of magnesium alloys were low for the load–bearing applications, and the corrosion resistance also needed to be improved furthermore. Design and preparing of a nanocomposite based on magnesium alloy might be an approach to this challenge. The aim of this work was to prepare and characterize of biodegradable magnesium–fluorapatite nanocomposite and to evaluate the effect of fluorapatite (FA) nano–particles content on microstructure, mechanical properties and bio–corrosion behavior of a nanocomposite (AZ91–FA) made of AZ91 magnesium alloy as matrix and FA nano-particles as reinforcement for load-bearing applications. Novel AZ91–FA (with 10 wt.%, 20 wt.%, and 30 wt.% of FA) nanocomposites were produced by AZ91 magnesium alloy powders and FA nano–particles using a blend–press–sinter powder metallurgy (PM) method. Microstructure, mechanical properties and bio–corrosion behavior of the prepared AZ91–FA nanocomposites, and also the AZ91 magnesium alloy as control sample, were evaluated.