3rd TAGRA

Surface degradation, wear debris generation, and metal ion release are major factors limiting the long-term performance of metallic biomedical implants. Nitrogen-based ceramic coatings, particularly titanium nitride (TiN), titanium carbonitride (TiCN), and titanium aluminum nitride (TiAlN), have attracted growing interest as surface modification strategies because they can enhance implant surface performance without substantially altering bulk mechanical behavior. This paper provides a general overview of the microstructure, surface morphology, phase composition, and mechanical properties of these coatings, along with their corrosion behavior and biocompatibility-related surface characteristics, with particular attention to how coating type and nitrogen content influence coating–substrate adhesion, surface roughness, and corrosion resistance. The literature indicates that TiN, TiCN, and TiAlN coatings can form dense, adherent, and chemically stable surface layers that, owing to their high hardness and chemical inertness, improve wear and corrosion resistance and may act as diffusion barriers limiting the release of potentially harmful metal ions in physiological environments. Nitrogen-based coatings are therefore promising candidates for improving the surface performance of biomedical implants, especially where wear resistance, corrosion protection, and biocompatibility are required. However, long-term osseointegration, cytotoxicity, and clinical performance remain insufficiently understood, and further in vitro and in vivo studies are needed.