Advanced Melting Techniques for Titanium and Zirconium Alloys and Tribological Studies in Medical Implant Manufacturing

The melting and casting of titanium (Ti) and zirconium (Zr) are crucial in foundries producing high-performance medical implants for orthopedic and dental applications. These reactive metals exhibit high melting points, exceptional corrosion resistance, biocompatibility, and thermal stability, making them ideal for medical devices. This study provides a comprehensive overview of advanced melting techniques such as Plasma Arc Melting, Electron Beam Melting (EBM), and Vacuum Arc Remelting (VAR), which ensure high purity and uniform composition. Foundry casting methods, including investment casting, centrifugal casting, and continuous casting, facilitate the fabrication of complex implant geometries. Additionally, additive manufacturing, specifically Laser Engineering Net Shape (LENSTM), enhances implant longevity, wear resistance, and corrosion performance. The production of pure Zr and Zr-50Ti alloy was conducted via laser-based melting and casting, followed by surface oxidation treatments. Oxide layers were successfully grown on Zr and Zr-50Ti surfaces, and detailed assessments of coating morphology, oxide phases, wear resistance, and corrosion behavior were performed. X-ray diffraction confirmed the formation of Zr and Ti oxides. Oxidation at 600°C for 6 hours yielded the lowest in-vitro wear rate (2.12 ± 0.36 × 10⁻⁶ mm³/N·m), attributed to the increased ceramic layer thickness. Furthermore, compared to untreated samples, oxidized surfaces exhibited significantly enhanced in-vitro corrosion resistance in Hanks' Balanced Salt Solution (HBSS). These findings demonstrate that controlled oxidation improves the functional performance of Ti- and Zr-based implants, making them more suitable for biomedical applications.