İbrahim Aydın

This study focuses on enhancing the biomedical performance of PBF-LB Ti6Al4V, produced using Selective Laser Melting (SLM), an advanced manufacturing technology widely used for patient-specific medical devices and implants. Hydroxyapatite (HA), titanium (Ti), and bilayer Ti/HA coatings were applied, using the powder flame spray coating technique. A comprehensive analysis was conducted to examine the microstructural, chemical, and mechanical properties of the coatings. Surface analysis was performed using a scanning electron microscope (SEM), chemical composition was determined by energy-dispersive spectroscopy (EDS), crystal structure was analyzed via X-ray diffraction (XRD), and surface roughness was evaluated through topographic analyses. Additionally, in vitro wear and corrosion resistance tests, crucial for biomedical applications, were conducted. In wear tests, HA coatings exhibited the lowest wear resistance with the highest wear rate (73.83 × 10⁻³ mm³/N·m), while Ti coatings showed the highest wear resistance (6.32 × 10⁻³ mm³/N·m), and Ti/HA coatings demonstrated an intermediate performance (34.22 × 10⁻³ mm³/N·m). Corrosion tests revealed that bilayer Ti/HA coatings provided the best protection (0.00009 mm/year), followed by Ti coatings (0.0002 mm/year) and HA coatings (0.003 mm/year). The results indicate that Ti/HA coatings offer the most suitable biomedical performance.

Ti and its alloys, which are commonly used in biomedical applications, are often preferred due to their proximity to the mechanical properties of bone. In order to increase the biocompatibility and bioactivities of these materials, biomaterials based on ceramic are used in coating operations. In this study, by using an electrophoretic deposition method, instead of on the Ti6Al4V alloy which is commonly used in the literature, a hydroxyapatite (HA) coating operation was applied on the surface of the Ti6Al7Nb alloy, and the surface properties of the coatings were examined. Ti6Al7Nb is a new-generation implant on which there have not been many studies. The voltage values which were used in the coating operation were 50, 100, 150 and 200 V, and the time parameter was stabilized at 1 min. In our method, when preparing the solution, HA, ethanol, and polyvinyl alcohol (PVA) were used. At the end of the study, by using an electron microscope (SEM) the microstructures of the coatings were examined; elemental analyses (EDS) of the coating surfaces were performed; and by using an X-radiation diffraction (XRD) method, the phases which the coatings contained and the concentration of these phases were determined, and the coating thickness, roughness, and hardness values were also determined. Also, by conducting a Scratch test, the strength of the surface combination was examined. At the end of the study, in each parameter, a successful HA coating was seen. By comparing parameters with each other, the ideal voltage value in this coating was determined. It was determined that the most suitable coating was obtained at 100 V voltage and 1 min deposition time.

Biomaterials utilized in implantation can be categorized into 4 main categories, as ceramics, polymers, metals and composites. Ceramic-based biomaterials are opted for, particularly in the field of orthopedics. These materials, also named as bioceramics, are usually employed by coating them onto the base material, inasmuch as they are far from the mechanical values of bone. In this study, a hydroxyapatite coating that is fully compatible with human blood plasma was applied on Ti6Al4V alloy through a biomimetic technique using aminoacetic acid-sodium aminoacetate buffer system for the first time in the literature, and examinations related thereto were carried out. The surface of the base material Ti6Al4V alloy was activated with various chemicals. Subsequent to activating the surface, a coating process whereby the base material was kept in simulated body fluid for 24, 48, 72, 96 h was carried out. Ultimate microhardness (indentation) tests were performed to determine the average indentation depths in maximum load, vickers hardness and elasticity modulus of the coatings obtained by using the biomimetic method, while scratch tests were performed to measure the surface bonding strengths of the coating layers. Furthermore, the fracture toughness values of the coating were calculated. The results obtained through the study are evaluated and discussed.