Partially biodegradable Ti-Mg composites prepared by microwave sintering for biomedical application

Partially biodegradable Ti-Mg composites were prepared by microwave sintering using the elemental Ti and Mg powders. The effect of Mg contents on the microstructure, mechanical properties, corrosion resistance, Mg degradation behavior of the Ti-Mg composites was investigated. The number of block Mg distributed over the Ti matrix gradually increases with increasing the Mg contents, in which the Mg and Ti form the metal-metal composite, and the interface of Mg and Ti is well bonded. The compressive strength of the Ti-Mg composites gradually decreases from 625 MPa to 357 MPa with increasing the Mg contents, while the elastic modulus varies little, ranged from 4.8 GPa to 5.7 GPa. The corrosion resistance of the Ti-Mg composites in SBF solution gradually decreases with increasing the Mg contents, resulting in the increase of hydrogen evolution amount. According to the electrochemical impedance spectroscopy, the corrosion and degradation of the Ti-Mg composites in SBF solution can be divided into three stages: the corrosion and degradation of Mg, the formation of Mg(OH)(2) layer and the dissolve of Mg(OH)(2) layer coupled with the formation of hydroxyapatite layer.