The Study On Surface Bionic-Activate And Biocompatibility Of β-Titanium Alloy

Ti-15Mo-3Nb alloys with better biocompatibility and mechanical consistency and without toxicity element was fabricated out in this work. The structure and constituents and performance were studied. We make bionic-activate treatment on the surface of Ti-15Mo-3Nb alloys with HNO₃ and KOH aqueous solution. Then the composite of potassium titanate/titanium alloys were gained. The coating of surface of this biomaterial was investigated using SEM, EDS, XRD. The surface morphology, phase constitution and combination between the layer and the matrix were analyzed and evaluated in this dissertation. The optimal processing parameters were obtained and the mechanics of activation was detected. The biocompatibility of this kind of composite was comprehensive evaluated with experiments of in vitro SBF cultivation, cell cultivation and dynamic blood coagulation and in vivo implantation. The results listed as follows:1. Ti-15Mo-3Nb alloy was fabricated by non-consumable vacuum arc smelting furnace. The microstructure of this alloy is homogeneous β phase structure.2. The bioactive gradient structure on the surface of Ti-15Mo-3Nb alloy was obtained by the acid and alkali treatment. An amorphous K₂Ti₈O₁₇ or K₂TiO₂ and TiO₂ layer with network surface morphology was observed. The optimal processing parameters is 3XHNO₃ under 60℃ for 10¹5 hours and 2M KOH aqueous solution under 85℃ for 9¹2hours.3. The bioactive surface induced the formation of hydroxyapatite (HA) layer by immersing the sample in SBF. Immersing the sample in SBF resulted in the fast formation of amorphous Ca-P particles in the frame of the active network, then nucleation and promoted the growth of HA.4. To evaluate the biocompatibility of materials in vitro, osteoblast cells(OCT-l) were cultivated with substitutes for bone tissue, including potassium titanate/titanium alloys and Ti-15Mo-3Nb alloys. The results showed that both materials had no obvious effect on the proliferation of the cells. Both materials were biocompatible to osteoblast cells.5. Experiment of blood coagulation: Extinction of potassium titanate layer is bigger than the titanium alloy in each time. This presents that blood in coating surface coagulation characteristic is weak, and the coagulation time is long. Extinction curve of potassiumtitanate layer is gentle in different time. This presents that blood in coating surface coagulation tendency is weak, and the coagulation time is long. In all the potassium titanate coating blood-compatibility surpasses the titanium alloy.6. Experiment of animal implantation: after potassium titanate/titanium alloy and titanium alloy implants 6 weeks, the surface of cortex bone has the new osteogenesis. The bone transforms actively. After the two planting materials implants 12 weeks, two sorts of plants unify closely between the body and the host bone. The amorphous matrix and the collagenous fiber distribute at random, the calcification degree misses slightly, presents that the osseous to be active. After the two planting materials implants 26 weeks, formed same bone union-shape in the cortex bone, the surface was encysted by new lamellar bone. The collagenous fiber bundled together in the osseous lamella, and arranges neatly layered. After acid-alkali treatment on the surface of titanium alloy, obtains composite ofpotassium titanate/titanium alloy. It has good biocompatibility, fine comprehensive mechanicsperformance and the shop characteristics. As replace-material and repair-material have broadclinical practice prospect.