This study investigates the influence of Ce concentration on the in-vitro bio-corrosion behavior, product film characteristics, and cytocompatibility of Mg–1Mn–xCe alloys (x \(=\) 0.5, 1, 3 wt%) in as-cast (AC) and as-homogenized (AH) conditions. The addition of Ce led to the formation of Mg₁₂Ce intermetallic phases, with increasing Ce content resulting in coarser and more interconnected precipitates. The AC Mg–1Mn–0.5Ce alloy underwent minimal dissolution due to the presence of fine and scattered precipitates, resulting in insufficient product film formation. In contrast, the AC Mg–1Mn–3Ce alloy displayed a semi-continuous secondary phase network that induced severe localized dissolution and non-uniform film formation. The AC Mg–1Mn–1Ce alloy exhibited the most favourable corrosion performance among the AC specimens, forming a compact and uniform product layer due to optimally sized and distributed precipitates. Homogenization treatment improved corrosion resistance across all compositions by altering secondary phase characteristics through solute redistribution. Notably, the AH Mg–1Mn–0.5Ce alloy demonstrated the highest corrosion resistance, attributed to the formation of fine, uniformly distributed Mg₁₂Ce precipitates that supported the development of a stable, hydroxyapatite (HAp)-rich corrosion layer. This HAp layer enhanced cytocompatibility by promoting cell adhesion and proliferation through structural similarity with natural bone mineral. The study provides comprehensive insights into the dual role of Ce concentration and homogenization treatment in tuning microstructural features to control corrosion behavior and improve biocompatibility. These findings offer a promising direction for designing biodegradable magnesium alloys with enhanced performance for biomedical implant applications.
