Fabrication and characterization of Ti-12Mo/xAl₂O₃ bio-inert composite for dental prosthetic applications

Introduction: Titanium (Ti)-molybdenum(Mo) composites reinforced with ceramic nanoparticles have recently significant interest among researchers as a new type of bio-inert material used for dental prosthetic applications due to its biocompatibility, outstanding physical, mechanical and corrosion properties. The current work investigates the impact of alumina (Al₂O₃) nanoparticles on the properties of the Ti-12Mo composite, including microstructure, density, hardness, wear resistance, and electrochemical behavior. Methods: Ti-12Mo/xAl₂O₃ nanocomposites reinforced with different Al₂O₃ nanoparticles content were prepared. The composition of each sample was adjusted through the mechanical milling of the elemental constituents of the sample for 24 h under an argon atmosphere. The produced nanocomposite powders were then cold-pressed at 600 MPa and sintered at different temperatures (1,350°C, 1,450°C, and 1,500°C) for 90 min. Based on density measurements using the Archimedes method, the most suitable sintering temperature was found to be 1,450°C. The morphology and chemical composition of the milled and sintered composites were analyzed using back-scattering scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results and Discussion: The results showed that the addition of Mo increased the Ti density from 99.11% to 99.46%, while the incorporation of 15wt% Al₂O₃ in the Ti-12Mo composite decreased the density to 97.28%. Furthermore, the Vickers hardness and wear behavior of the Ti-Mo composite were enhanced with the addition of up to 5 wt% Al₂O₃. The sample contains 5 wt% Al₂O₃ exhibited a Vickers hardness of 593.4 HV, compared to 320 HV for pure Ti, and demonstrated the lowest wear rate of 0.0367 mg/min, compared to 0.307 mg/min for pure Ti. Electrochemical investigations revealed that the sintered Ti-12Mo/xAl₂O₃ nanocomposites displayed higher corrosion resistance against a simulated artificial saliva (AS) solution than pure Ti. The concentrations of Ti, Mo, and Al ions released from the Ti-12Mo/xAl₂O₃ nanocomposites in the AS solution were within the safe levels. It was found from this study that; the sample of the composition Ti-12Mo/5wt%Al₂O₃ exhibited appropriate mechanical properties, biocompatibility, corrosion resistance against the AS solution with acceptable ion concentration released in the biological fluids. Therefore, it can be considered as a new bio-inert material for potential applications in dental prosthetics.