A new variant of friction-assisted process named friction surface alloying (FSA) for developing surface alloys was demonstrated in the present work. In FSA, the dispersed phase is melted and allowed to react with the matrix material to form an alloy at the surface of a metal-lic substrate. In the present work, magnesium (Mg) sheets and zinc (Zn) powder were selected, and fine grained (～3.5 μm) Mg–Zn surface al-loy with improved hardness was produced by FSA. X-ray diffraction studies confirmed the formation of intermetallic phases of Mg and Zn at the surface. From the in vitro degradation studies carried out by immersing in simulated body fluids, a lower corrosion rate was observed for the Mg–Zn surface alloy compared with pure Mg. The surface morphologies after immersion studies indicated large degraded areas on the base Mg compared with Mg–Zn. The results demonstrate the potential of FSA in developing Mg-based surface alloys without melting the substrate to impart better surface properties.