| Hydroxyapatite?HA?composite coatings have good biocompatibility used as bone substitute materials,which their application are limited in bioceramic materials due to their poor mechanical properties.In order to alleviate the phenomenon that the thermal expansion coefficient of the coating material does not match during the sintering process,and to achieve the purpose of improving the binding strength of the coating,the method of adding binary osteogenic trace elements to select the zone electrophoresis distribution and electrophoretic deposition method are adopted in this experiment.A HA composite coating functionally graded material was prepared.In order to prepare the HA composite coating gradient material with strong binding ability,n-butanol is used as dispersion medium,chitosan is selected as pore-forming agent,and the titanium metal sheet as substrate is applied.One binary osteogenic compound Al?OH?3 is combined,and the other osteogenic trace element compound SiO2,ZnO,or SrCO3.HA/CS/Al?OH?3/SiO2,HA/CS/Al?OH?3/ZnO and HA/CS/Al?OH?3/SrCO3 coatings were prepared by zone electrophoresis and electrophoretic deposition.The sinter ing HA/Al2O3/SiO2,HA/Al2O3/ZnO,HA/Al2O3/SrCO3 coatings with obvious gradient property are characterized by EDS,FT-IR,universal material testing machine,XRD,SEM and electrochemical workstation are employed to investagete the composition,binding strength,crystal form,surfacial morphology and corrosion resistance of the coatings.The antibacterial property and in vitro biological activity of the gradient coatings are evaluated finally.The experimental results show that the binding strength between HA/Al2O3/SiO2,HA/Al2O3/ZnO,HA/Al2O3/SrCO3 gradient coatings and titanium metal substrate is up to 33.8 MPa,33.2 MPa and 33.6 MPa,respectively.Their binding strengths of the 3 gradient coatings are superior to these coatings prepared by electrophoretic deposition only.The 3 gradient coatings have excellent corrosion resistance and bacteriostasis in HEPES simulated body fluids.The self-corrosion current density and self-corrosion potential are 1.276×10-7 A·cm-2,1.496×10-7 A·cm-2,5.373×10-8 A·cm-2 and-0.158 V,-0.297 V,-0.15 V;the inhibition rates against Escherichia coli were86.7%,91.6%and 89.7%,respectively.The inhibition rate against Bacillus subtilis were 89.3%,90.8%and 82.3%.the inhibition rates against Staphylococcus aureus were 91.4%,92.4%and 94.6%,respectively.the inhibition rates against MRSA were 90.2%,87.3%and 92.3%,respectively.It's noticed that the HA/Al2O3/SrCO3 composite coating with functionally graded property possesses the most outstanding binding strength,corrosion resistance,bacteriostasis and in vitro biological activity,and is more suitable for application as human bone substitute material. |
PDF Full Text Request