A Continuous MgF2 Network Structure Encapsulated Mg Alloy Prepared by Selective Laser Melting for Enhanced Biodegradation Resistance

Magnesium (Mg) alloys have been regarded as potential biodegradable metals but degrade too fast in the physiological environment. Herein, a continuous magnesium fluoride (MgF2) network structure is designed and induced into Mg alloy to improve the degradation resistance. For this purpose, Mg alloy particles are first treated by hydrofluoric acid (HF) and then used to prepare alloys via selective laser melting (SLM). The results show that an intact and tightly packed MgF2 layer generates on the surface of Mg alloy particles. After SLM, the alloy presents a continuous network structure, in which Mg alloy matrix is encapsulated in the network units constructed by MgF2. Owing to the high corrosion resistance and chemical inertness of MgF2, the continuous network structure resists the erosion of corrosion medium and decreases the degradation rate of Mg alloy by 21%. In addition, cell fluorescence and viability results show that the network structure encapsulated Mg alloy exhibits improved cell proliferation and adhesion ability, indicating better biocompatibility. These findings show that the airtight network structure might be a good way to improve the degradation resistance of Mg alloys for biomedical applications. A tightly packed MgF2 layer is prepared on the surface of Mg alloy powder by hydrofluoric acid (HF) treatment and Mg alloys encapsulated by MgF2 network structure are fabricated via selective laser melting (SLM). The obtained continuous and encapsulated network structure is a promising strategy to promote the biodegradation resistance of Mg alloys in the whole degradation process.