⭐ Article highlights: The influence of nitrogen ion implantation on the microstructure and chemical composition of a thin layer on the biodegradable Zn-0.8Mg-0.2Sr substrate

Highlights:

• Nitrogen ion implantation of biodegradable Zn-Mg-Sr alloy
  Investigates how N⁺ ion implantation modifies the surface microstructure and chemistry of biodegradable Zn-0.8Mg-0.2Sr alloy.
• Surface modification for biodegradable implant applications
  Explores ion implantation as a promising approach for improving surface properties of Zn-based implant materials.
• Formation of nano/micro-porous surface layers
  Shows that high-fluence nitrogen implantation creates porous modified layers on pure Zn and Mg₂Zn₁₁ surfaces, reaching thicknesses up to 400 nm.
• Distinct behavior of alloy and individual phases
  Compares implanted pure Zn, Mg₂Zn₁₁, and Zn-0.8Mg-0.2Sr alloy to clarify how each phase contributes to the final surface structure.
• Mg enrichment of the alloy surface
  Reveals a strong increase in surface Mg content from 0.8 to approximately 15 wt.% due to Mg₂Zn₁₁ decomposition and Mg diffusion.
• Limited formation of magnesium nitride and oxide
  Confirms partial formation of Mg₃N₂ and MgO on Mg-rich regions, while zinc nitride was not detected.
• Absence of Zn₃N₂ explained by thermodynamics
  Attributes the lack of zinc nitride to low Zn-N affinity and the thermodynamic instability of Zn₃N₂ compared with Mg₃N₂.
• Nitrogen retention in implanted zinc
  GD-OES detects nitrogen in pure Zn despite the absence of Zn₃N₂, suggesting possible accommodation of N atoms in interstitial positions.
• Combined experimental and simulation approach
  Uses TRIM and TRIDYN simulations together with SEM, TEM, GD-OES, XRD, XPS, and AFM to describe implantation-induced changes.
• Potential for future biomedical surface engineering
  Highlights possible applications in cell adhesion improvement, degradation control, reactive surface design, and drug-delivery-related porous structures.