Laser Additively Manufactured Iron-Based Biocomposite: Microstructure, Degradation, and In Vitro Cell Behavior

A too slow degradation of iron (Fe) limits its orthopedic application. In this study, calcium chloride (CaCl₂) was incorporated into a Fe-based biocomposite fabricated by laser additive manufacturing, with an aim to accelerate the degradation. It was found that CaCl₂ with strong water absorptivity improved the hydrophilicity of the Fe matrix and thereby promoted the invasion of corrosive solution. On the other hand, CaCl₂ could rapidly dissolve once contacting the solution and release massive chloride ion. Interestingly, the local high concentration of chloride ion effectively destroyed the corrosion product layer due to its strong erosion ability. As a result, the corrosion product layer covered on the Fe/CaCl₂ matrix exhibited an extremely porous structure, thus exhibiting a significantly reduced corrosion resistance. Besides, in vivo cell testing proved that the Fe/CaCl₂ biocomposite also showed favorable cytocompatibility.