| In order to improve the corrosion resistance and blood compatibility of the biomedical materials TC4 titanium alloy, rough porous TiO2 ceramic coatings were prepared on TC4 titanium alloy by micro-arc oxidation and rough Na2Ti6O13 ceramic coatings were prepared by alkali solution hydrothermal treatment. Subsequently they were both turned into superhydrophobic coatings by immersing in the 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane ethanol solution. Microstructure and composition of the superhydrophobic coatings were observed by SEM ? XRD ? EDS and XPS. The wettability was measured by contact angle meter, the corrosion resistance was discussed by electrochemical workstation and the biological properties were discussed through blood compatibility test and antibacterial test, respectively.The miro-arc oxidation ceramic coating was mainly composed of anatase TiO2,and its surface exhibited porous and roughness. The roughness of coatings increased with increasing the positive voltages and treating times, respectively, and decreased with increasing the pulse frequency. The alkali solution hydrothermal treated ceramic coating was mainly composed of Na2Ti6O13 phase, and its surface showed the needle type and existed many micro cracks. The roughness increased with increasing the concentrations of NaOH.The ceramic coatings prepared by the two kinds of surface modification had micro-nano rough structure,and the super hydrophobic coating could be obtained by self assembly technology. The results showed that the maximum of CA could reach155 degree optimized by the parameters of the micro arc oxidation and hydrophobic treatment. The maximum of CA could be up to 159 degree, optimized by the parameters of the alkali solution hydrothermal treatment and hydrophobic treatment.They both had the superhydrophobic property. The superhydrophobic coatings inhibited the release of Al and V ions,which had a great influence on the human body in TC4 titanium alloy. The Al element content was about 1.51% and V was about0.10% in coatings obtained by EDS analysis. The results of XPS analysis showed that the coatings existed many hydroxyls,which would combine with hydroxyl group of PFOTS ethanol hydrolysis, and then a low surface energy material molecular film formed on the surface of the ceramic coating layer. Finally, the super hydrophobic property was obtained.The corrosion current density(Icorr)of TC4 titanium alloy substrate was3.393×10-7A/cm-2,the polarization resistance(Rp) was 1.17×105 ?/cm2, while the Icorr of the MAO-super hydrophobic coating was 2.139×10-8 A/cm-2 and the Rp was2.07×106 ?/cm2. The Icorr of hydrothermal treatment-super hydrophobic coating was6.336×10-8A/cm-2and the Rp was 3.42×105 ?/cm2. The corrosion current density of superhydrophobic coatings were an order of magnitude lower than that of the TC4 and the polarization resistance was also larger than that of the substrate, indicating that the superhydrophobic coatings greatly improved the corrosion resistance of the substrate.According the results of hemolysis ratio,kinetic clotting time and platelet adherence from these coatings,it can be concluded that the hemocompatibility of TC4 alloy can be markedly improve after prepared with super hydrophobic coatings. The antibacterial experiment showed that the super hydrophobic coating had the least amount of bacteria adhesion, which indicated that the super hydrophobic coatings can effectively improve the antibacterial properties of TC4 titanium alloy. |
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