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

Weiyan Jianga Jingfeng Wanga Wenzhou Yua Yao Maa Shengfeng Guob

• a National Engineering Research Center for Magnesium Alloys, College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China

• b Faculty of Materials and Energy, Southwest University, Chongqing 400715, China

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.

https://www.sciencedirect.com/science/article/abs/pii/S0257897218314324