Effect of alloyed Sr on the microstructure and corrosion behavior of biodegradable Mg-Zn-Mn alloy in Hanks' solution

Effect of Sr on microstructure and corrosion behavior of biodegradable Mg-1Zn-1Mn-xSr alloy is investigated. Decrease in second phase spacing and linear increase of Mg17Sr2 fraction are observed with increasing Sr content. Corrosion rate increases linearly with increasing Sr content from 0 to 1.5 wt.% because of the enhanced micro-galvanic corrosion. Undermining of Mg17Sr2 and alpha-Mg grains results in the dramatic increase in corrosion rate at a high Sr content (3.0 wt.%). Localized corrosion is inhibited by alloying with Sr, yielding an optimum Sr content of 1.0(similar to)1.5 wt.% with comprehensive consideration of uniform/localized corrosion resistance and biomedical adaptability.