| With the improvement of people's living standards,the development and application of biological materials are attracting more and more attention.Many metals and their alloy materials have been widely used in the field of biomaterials due to its good biological properties and mechanical properties.Ti-6A1-4V alloy and commercial pure Ti are the most commonly used materials for biomedical implant applications.However,more and more concern has been considered due to the toxicity of aluminum and vanadium released from Ti-6AI-4V alloy.Besides,the low strength and poor wear resistance of cp Ti limits its uses in clinical applications.The development of titanium alloys with the same mechanical properties as Ti-6A1-4V becomes the hot topic.Both Ti and Zr are in the same main family.Zr is non-toxic and has no side effect.Besides the development of ZrTi alloy is a hot spot in biomaterial,these two aspects of advantages may have huge influence on by biomaterial.However,because ZrTi alloy behaves the low wear resistance and bioactivity,surface modification approach is used to improve its wear resistance and biological activity.In this paper,ZrTi binary alloy was used as the object,the wear resistance coating and self-assembled nanotube coating were prepared by thermal oxidation and anodic oxidation method,respectively.ZrTi alloy thermal oxidation coating and nanotube coating phase composition and morphology were studied by the OM,XRD,SEM and other methods of analysis and testing system,were tested the hardness and binding force,friction and wear properties and biological activity.Experimental results show that after oxidized for 2h in 500?,Zr-20Ti alloy surface morphology is smooth,no big hole and more compact.It will generate m-ZrO2 and ZrTiO4 ceramic coating which the microhardness can reach above 1300HV.After oxidized for 2h in 500?,Zr-40Ti alloy surface morphology is relatively smooth.And oxidation layer is relatively dense.Phase was composed of ZrTi04 ceramic composition which micro hardness reached 1400HV.The oxide coatings thickness on Zr-20Ti and Zr-40Ti was between 10?m and 20?m.The binding force was up to 50N,superior to those formed by plasma spraying,magnetron sputter ion plating and micro-arc oxidation method.Zr-60Ti alloy in 500? after oxidized for 2h,the surface is smooth.The oxide coatings are made of TiO2 and ZrTiO4 ceramics which the oxide layer is thin,and the thickness is only about 2?m.Friction and wear tests show that the friction coefficient of Zr-20Ti and Zr-40Ti alloy are similar.The friction coefficient of Zr-20Ti is stable at 0.34.And the friction coefficient of Zr-40Ti is about 0.40.The friction coefficient of the Zr-60Ti alloy is slightly different,and the friction coefficient is 0.40.The wear mechanisms of Zr-20Ti and Zr-40Ti alloys are wear particles,and the adhesion wear the Zr-60Ti alloy is main the adhesion wear.The experiment showed that in the 1mol/L(NH4)2SO4 and 0.141mol/L NH4F electrolyte,the self-assembled nanotubes which were prepared under the anodic oxidation of 20V voltage using the 2h are most complete.Zr-60Ti self-assembled nanotubes are most flat,followed by Zr-40Ti self-assembled nanotubes.Zr-20Ti self-assembled nanotube surfaces are most uneven.The nanotube coating of ZrTi alloy was thicker and reached 6-9 ?m.Zr-20Ti is generated on the surface of the self-assembled nanotubes deposited mainly ?-Ca3(PO4)2.Zr-40Ti first deposition ?-Ca3(PO4)2,then it is transformed into hydroxyapatite.The surface of the Zr-60Ti self-assembled nanotubes directly deposited hydroxyl apatite.The hydrophilic properties of the self-assembled nanotube coatings of ZrTi alloy are good.And the hydrophilic property of Zr-20Ti self-assembled nanotubes arer elatively good. |
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