Corrosion Behavior of Embedded Perforated Biodegradable Mg/Fe Composite Plate

Magnesium is one of promising biodegradable metals for medical application. But the high degradation rate limits its further applications. Combining Mg with other biodegradable materials to form composite is an efficient approach. Herein, Mg/Fe laminated composites were prepared by laser drilling followed by hot rolling. The micro-hole array was fabricated in pure iron using femtosecond laser firstly, and then the Mg plates and Fe foil were alternately stacked and rolled. Magnesium passed through the micro-holes and interconnected each other to form a metallurgical bonding during rolling process. As a result, the Mg/Fe composites exhibited a tensile strength of 178.94 ± 3.03 MPa. Immersion tests show that localized corrosion occurred in the Mg layer firstly. With the increase of immersion time, the corrosion products increased and gradually covered the composite surface. After immersion for 8 h, the Mg layer surface was completely corroded, while the Fe layer surface still retained smooth and no obvious defect was observed. However, the corrosion microcracks were also formed along the Mg/Fe interface.