Mg-xSi（x=0.6、1.38、2.1

weight fraction

%）binary alloys were prepared.The solidification microstructure of the alloys prepared was oberved using OM.The bio-corrosion behavior of the alloys in simulated body fluid was evaluated by means of hydrogen evolution test

mass loss tests and electrochemical test

and the optical corrosion morphologies were observed by the SEM.The results reveal that the eutectic Mg

2

Si phase is changed from fine lamellar to Chinese character with increasing in Si addition.Moreover

the particle size of granular primary Mg

2

Si phase is further decreased.With increasing in Si addition

the hydrogen evolution rate

the corrosion rate and the corrosion current density of the alloys are increased gradually

which show that the corrosion resistance of the alloys in simulated body fluid is decreased gradually.