Corrosion Mechanisms of a Biodegradable Zn-0.4Li Alloy in Simulated Gastrointestinal Environment

Zn-Li alloys have been demonstrated to be potential biodegradable materials because of their favorable biocompatibility and exceptional strength. The corrosion behaviors of Zn–0.4Li in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were investigated. Compared with samples in SIF, those in SGF were severely corroded locally. Pepsin and pancreatin participated in the formation of degradation products. After immersion in SGF and SIF, the corrosion process presented two interfaces. Lithium (Li) preferentially reacted in the near-surface region to form a Li-rich region. Simultaneously, there were two Li-poor regions around the Li-rich region. Then Zn-rich products gradually became dominant with time. Li+ releasement dominated over Zn2+ releasement throughout the immersion process in SGF and SIF. These results can guide the development of biodegradable gastrointestinal anastomotic nails in the future.