Titanium-based composites with in-situ calcium and phosphor phases were prepared by powder metallurgy processing with titanium and hydroxyapatite (HA) powders. The mixtures were performed in a friction mill with alcohol for 5 hours, dried in a rotating evaporator, pressed at 600 MPa and sintered at 1200 °C for 2 hours in argon atmosphere. Crystal phases of the as-fabricated composite are found to be, α-Ti, CaTiO 3 , Ca 3 (PO 4 ) 2 and Ti x P y phase(s). The analyses revealed that titanium particles were covered with a compact layer of Ti x P y and CaTiO 3 phases, which resulted from the decomposition of HA into CaTiO 3 and β-Ca 3 (PO 4 ) 2 at approximately 1025 °C. Then the reactions were followed by the decomposition of β-Ca 3 (PO 4 ) 2 , resulting in the growth of CaTiO 3 layer and in the nucleation and growth of Ti x P y phase(s).
In recent years, intensive development of dentistry stimulates the demand for new titanium implant materials created by surface engineering. Plasma nitriding is proposed as a solution to improve the biocompatibility. This work investigated the influence of plasma carbonitriding on the roughness and contact angle of Ti6Al4V treated in a Ar / N 2 / CH 4 plasma for 3 h and 6 h at 600 °C. The characterization was made by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Theta Lite Optical Tensiometer, and laser confocal microscopy. The XRD results indicated the formation of Ti 3 N 1.29 and Ti 2 N phase. It was observed that the surface roughness increases from 0.24 to 0.87 μm after 3 h and from 0.24 to 1.09 μm after 6 h of carbonitriding. The contact angle was 38° and 30° for 3 h and 6 h, respectively.
In this study a modified Kokubo's treatment (MKT) was used to bioactivate titanium implants. Titanium surfaces were alumina-blasted and etched in HCl/H 2 SO 4 solution followed by treatment in autoclave at 120˚C for 1, 3, 5 hour periods with chemical solutions containing 1, 2 and 3 M of NaOH. The materials were characterized by surface angle measurements, roughness, field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and in vivo tests. Statistical analysis by polynomial regression showed that solutions within 2.2 and 2.8 M NaOH lead to surface contact angles close to zero degree after 1 h of treatment. XPS analysis carried out on a sample treated 1 h in 2.2 M NaOH indicated the presence of a titanate film. This solution was selected to treat titanium implants for in vivo tests. These tests were performed on sheep in three types of separating surfaces: machined group (standard), SLA group (A) and MKT group (B) divided into two time intervals of 3 and 6 weeks. The samples in group B displayed better results compared to group A only after 6 weeks in terms of counter torque and bone implant contact (BIC).
Titanium-based composites containing TixPy phase (s) or CaTiO3 and TixPy phase (s) were produced by a non conventional method using suitable mixtures of TiH2 powder and phosphoric acid (TiH2/P), or TiH2 and 10 vol.% of calcium phosphate (TiH2/CP), respectively. The composites were produced with the same phosphor molar concentration. The mixtures were prepared by ultrasound in water, dried in a rotary evaporator, pressed at 600 MPa and vacuum-sintered at 1200 °C for 2 hours. The mixtures were well dispersed by ultrasound and agglomerate-free. The analyses show that titanium particles were coated with TixPy phase (s) for the TiH2/P composite or with an intermediary layer of TixPy phase (s) and an external deposit of calcium titanate for the TiH2/CP composite. The TiH2/P composite presented higher compressive strength and about the same contact angle compared to the TiH2/CP composite. However, both materials displayed lower contact angle than that of pure titanium.
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