In-situ formation of a gradient Mg2Si/Mg composite with good biocompatibility

Abstract

A novel Mg2Si/Mg gradient composite was in-situ produced by electromagnetic directional solidification (EMDS). The microstructure of the composite changed longitudinally along with a primary Mg2Si-rich layer at the bottom and a Mg-rich eutectic layer at the top, respectively. The bio-corrosion behavior was investigated by electrochemical studies and static immersion tests. Both layers exhibited a much higher bio-corrosion resistance than high-pure Mg. Especially, the primary Mg2Si-rich phase revealed the greatest bio-corrosion resistance due to the corrosion blocking effect. Additionally, all the components originated from the gradient composite showed a good biocompatibility without obvious toxicity to osteoblasts. This work provided a new insight into the designing of gradient Mg2Si/Mg composite as a promising candidate for orthopedic implants.