Effect of Sintering Time on the Mechanical and Corrosion Behavior of Zn–Mg Composites with a Core–Shell Structure Prepared by SPS

Abstract

Zn-10 Mg composite with a core-shell structure was prepared by spark plasma sintering (SPS) technology, and a systematic study of the microstructure and properties has been conducted for different sintering times. The shell layer dominated by the hard MgZn 2 phase thickens with the increase in sintering time, which has a positive effect on the mechanical and degradation properties of the material. The sample sintered for 20 min (T-20) has the best mechanical properties, with a compressive strength of 226 MPa and a compression rate of 6.5%. The corrosion resistance of samples increases as the sintering time prolongs, while the hydrogen evolution volume and pH value decrease in the immersion experiment. Furthermore, the increase in the shell thickness significantly reduces the corrosion rate, which is attributed to the weakening of the galvanic corrosion reaction between the Mg core and the MgZn 2 shell. Therefore, composite with unique core-shell structure provides an advanced design idea for degradable biomaterials, and a reasonable control of sintering time can provide the optimal design strategy.