Preparation And Performance Study Of Nano-hydroxyapatite Composite Coatin

Bone replacement materials have always been the research focus in the biomedical field.Ti-6Al-4V alloy has good mechanical properties and corrosion resistance.It is mainly used as bone replacement materials in medical applications.However,in clinical research,it was found that the implanted Ti-6Al-4V alloy will precipitate harmful ions after been used for few years.The ions will seriously hurt the human health,and bone cells cannot adhere and grow on its surface.Therefore,a biologically active coating material is deposited on the Ti-6Al-4V alloy substrate to solve the problems of the material itself in terms of microstructure,interface strength and biocompatibility.In view of the the chemical composition of hydroxyapatite(HA,Ca₁₀（PO₄）₆（OH）₂)is very similar to that of human bone,and has excellent biocompatibility and bioactivity,the application of HA to the surface of titanium alloys can improve the matrix material The mechanical properties and biological activity make it have good biocompatibility.In view of the problems of poor bonding performance between HA coating and the surface of titanium alloy substrate,which may be easy to peel off and prone to cracks on the surface,this paper uses radio frequency magnetron sputtering technology to deposit HA coating on the surface of titanium alloy substrate,and explores the effect of introducing transition layer Zr N.Performance differences of composite HA coatings.The research work focuses on coating preparation,mechanism analysis and simulated body fluid immersion experiments.The microscopic morphology,mechanical properties,phase composition,wettability,corrosion resistance and biocompatibility of the coatings are analyzed,and relevant conclusions are obtained.In this paper,the effects of heat treatment on the microstructure,phase structure and corrosion resistance of HA coatings were studied.The research results show that under the condition of heat treatment,the microstructure,phase structure and corrosion resistance of the single-layer HA coating are significantly improved,the crystalline spherical particles on the surface of the coating are denser,and the roughness is significantly increased is closer to the theoretical value of 1.67 after heat treatment,and the content of Ca and P elements is significantly increased,and the phase structure is closer to the standard value of HA;the open circuit potential of the HA coating after heat treatment is higher than that of the HA coating without heat treatment,and the corrosion resistance The performance is improved compared to before heat treatment.The Zr N transition layer prepared by research has good tribological properties,smooth surface,relatively uniform crystal particles,and its surface roughness is similar to that of HA.The phase structure mainly grows along the（200）crystal plane,which meets the structural requirements of the transition layer.The effects of different deposition parameters on the microstructure,mechanical properties,mechanical properties,corrosion resistance and wetting properties of composite Zr N-HA coatings were investigated.The research results show that the sputtering power and Ar₂ pressure have great influence on the properties of the coating.Overall,when the sputtering power is 230W and the Ar₂ pressure is 0.8Pa,the performance of the composite coating is the best.Under these sputtering parameters,the microscopic surface morphology of the coating shows that the hemispherical crystal particles are obvious and uniformly distributed,and no defects are generated;the Ca/P ratio of the coating surface is closest to1.67,and when the Ar₂ pressure gradually increases,the composite coating has a The Ca/P ratio gradually decreases.The diffraction characteristic peaks of the composite coating are basically consistent with the HA standard,and tend to be stable with the changes of sputtering power and Ar₂ pressure.The maximum film-substrate interface bonding force of the composite coating is 21.3N,which is greatly improved under the influence of deposition parameters.The contact angle of the coating decreases gradually with the increasing sputtering power and Ar₂ pressure,the wettability of the coating surface is improved,and the cells are more likely to attach and grow on the coating surface.It has strong plastic deformation resistance and excellent mechanical properties.Compared with the single HA coating,the open circuit potential and corrosion current of the composite coating are higher than those of the single layer,and its corrosion resistance is significantly improved.The microstructure,mechanical properties,mechanical properties,corrosion resistance and wetting properties of the composite Zr N-HA coating were significantly improved.The study also carried out SBF simulated human body fluid immersion experiments to examine the feasibility of the composite coatings prepared in this paper to be applied to bone replacement materials.The research results show that soaking in human body fluids will change the microscopic surface morphology and element content of the composite Zr N-HA coating.The content of Ca element is stable at 25%after soaking,and the bones inductive deposition of new substances in the SBF solution can be clearly observed.Crystallization The particle size is larger and the distribution is uniform,and the biocompatibility of the composite coating is significantly improved;the Ca/P ratio of the coating is also significantly improved after soaking,which is closer to the theoretical value.It is verified that the composite Zr N-HA coating has good biocompatibility and biological activity,and can be applied to bone replacement materials..