The Study On Surface Activate Treatment And Biocompatibility Of Ti-15Mo-3Nb

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. The surface of Ti-15Mo-3Nb alloys was in-turn chemically activated with HNO3 and KOH aqueous solution. The bioactive surface induced the formation of hydroxyapatite (HA) layer by immersing the sample in SBF. Then the composite of HA/potassium titanate/titanium alloys were gained. SEM,EDS,XRD were used to investigate the coating of surface. The surface morphology, phase constitution and biocompatibility of the material were analyzed and evaluated. 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 cell cultivation 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. The bioactive gradient structure on the surface of Ti-15Mo-3Nb alloy by the acid and alkali treatment. An amorphous K2Ti8O17 or K2Ti2O5 and TiO2 layer with network surface morphology was observed. The optimal processing parameters is 2M KOH aqueous solution under 110℃ for 5 hours after the HNO3 treatment.2.The bioactive surface induced the formation of hydroxyapatite (HA) layer by immersing the sample in SBF. Then the composite of HA/potassium titanate/titanium alloys were gained. 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. It was found that the rate of apatite formation on surface of titanium alloys was significantly enforced by pre-calcification after alkali-treatment.3. To evaluate the biocompatibility of materials in vitro, osteoblast cells(OCT-1) were cultivated with substitutes for bone tissue, including HA/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. Both materials could promote the migration and attachment of osteoblasts to them. The cells attachment shape and proliferation rate of cells were good. While HA/potassium titanate/titanium alloys was a better substitute for bone tissues, for it has better osteogenic action.4.The materials were implanted in the subcutaneous part of rabbit and tissue was observed. In the implanting tissues for 1 week, the cyst wall, which formed by proliferation of connective tissue, was loose and thick. In the implanting tissues for 4 weeks, inflammatory reaction is reduced .It was observed that neutral cells was few, only a few of lymphcytes and monocytes exist. Thickness of fibre membrane reduced and collagenous fiber tissue formed. In the implanting tissues for 12 weeks, inflammatory reaction was almost disappeared and the density of inflammation cells is less .The cyst wall was very thin and compact while the proliferation stopped. The results show tissue reaction caused by the materials is gentle.