| On the metal substrate preparation of bioactive ceramic material, can satisfy the mechanical properties of the implant requirement, and has implanted in the body of the biological active demand, is now the most widely used bone implant of substitute materials. Preparation of hydroxyapatite coating on titanium alloy(Ti-6Al-4V) matrix,the implant has been widely used in clinic, but the pure hydroxyapatite coating and titanium alloy substrate bond strength is not high, the impact of the its application in the field of biological materials, this paper by using plasma spraying method of titanium / hydroxyapatite composite coatings on titanium alloy were prepared. In order to improve the interface between the coating and the substrate bonding strength,and demonstrate its biocompatibility.Using the method of plasma spraying on titanium alloy(Ti-6Al-4V) preparation of hydroxyapatite coating on the substrate, through the analysis of hydroxyapatite coating microstructure, porosity, binding strength of coating properties were characterized, and the effect of processing on the properties of coating hydroxyl apatite, analysis results show that: plasma spraying spraying power is 40 kW, in spraying distance were 80 mm, 100 mm, 120 mm, through the analysis of flat particle size to determine the extent of melting of the powder particles, the spraying power40 kW, spraying distance increases to 100 mm the degree of melting of coating powder particles from the 80 mm well, the spraying distance increases to 120 mm coating powder particles from the 100 mm melt decreased flat, fell flat particle; spraying distance of 100 mm under the same condition, the spraying power increased from30 kW to 50 kW, changed particle morphology of hydroxyapatite coating powder, the extent of melting particles significantly better; hydroxyapatite coating specimens with porosity of 5%-10%, the change range is not big. When the spraying power unchanged, the porosity of the coating with spray distance increases first becamesmaller and then become larger, when the spray distance unchanged, with spraying power increasing coating porosity decreases; power is 40 kW spraying, spraying distance of 100 mm parameters, the HA coating binding strength is the highest,reaching 15.8Mpa.Selects the optimal plasma spraying process of different composition of titanium/ hydroxyapatite composite coatings were prepared. The spraying power is 40 kW,spraying distance of 100 mm spray parameters, were of two kinds of HA / Ti composite coatings were prepared by: coating HA/Ti30wt% H7T3 and HA/Ti50wt%coating H5T5. The microstructure, porosity, composition of the composite coating,the bonding strength of the coating were analyzed.. The results show that: particles deformation obviously, fusion degree is good, flat particles are added together, the edge has obvious traces of sputtering, powder melting degree is high, the coatings are compact, with small pores, between the coating and the substrate, the surface of the composite coating showed no obvious crack; H7T3 composite coating of titanium the quality of the proportion is 15.81%, the H5T5 composite coating of titanium in the mass fraction of 27.10%, indicating the deposition efficiency of titanium powder is not high, compared to the quality of spraying powder was decrease in porosity; H7T3 composite coating was 4.2%, H5T5 composite coating porosity is 3.6%, two kinds of composite coating porosity relatively close, contrast of hydroxyapatite coating porosity of 5.1%, due to the larger particle size of titanium powder to composite coating porosity is relatively low; the bonding strength of 22.4MPa bond strength is higher than the H7T3 19.6 MPa composite coating H5T5 composite coating, with increasing titanium content in the coating, which combines the increasing strength of composite coating. The bonding strength of the hydroxyapatite coating was 15.8 MPa with the same spraying parameters, and the bonding strength of the titanium /hydroxyapatite coating was higher than that of the pure hydroxyapatite coating.Cell culture test results show that: according to the evaluation of cellmorphological changes, H5T5 composite coating test component normal cell morphology, cell toxicity for non-toxic; using scanning electron microscopy(SEM)cell adhesion on the sample. The results showed that bone marrow mesenchymal stem cells on titanium / hydroxyapatite proliferation of the specimen surface strong,cytotoxicity is non-toxic, good cell adhesion; CCK-8 cell toxicity test results show that, the titanium / hydroxyapatite composite coating specimen group cell relative proliferation rate was above 85% and toxicity was graded as grade 1, no cell toxicity.According to the cell culture experiments of the composite coating in group 1, 4, 7 d cell morphologic changes in each group, the relative proliferation rate of cells,toxicity grading and cell adhesion of results analysis, show that the H5T5 composite coating has good cell compatibility. |
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