Effects of Zr Content on the Electrochemical Characteristics of Nano-Structure Controlled Ti-alloys

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Objective: Pure Ti as well as Ti-6Al-4V alloy exhibit excellent properties for dental implant applications. However, for a better biocompatibility it seems important to avoid in the composition the presence of V due to the toxic effects of V ion release. Thus Al and V free and composed of non-toxic element such as Nb, Zr alloys as biomaterials have been developed. Especially, Zr contains to same family in periodic table as Ti. Addition of Zr to Ti alloy have an excellent mechanical properties, good corrosion resistance, and biocompatibility. In this study, effects of Zr content on the electrochemical characteristics of Ti alloy for biomaterials have been investigated using by electrochemical methods. Methods: Ti-Zr(10, 20, 30 and 40 wt%) alloys were prepared by arc melting and nano-structure controlled for 24 hr at 1000 °C in argon atmosphere. Phase constitutions and microstructure of the specimens were characterized by XRD, OM and SEM. The corrosion properties of the specimens were examined through potentiodynamic test ( potential range of -1500 ~ 2000 mV), potentiostatic test (const. potential of 300 mV) in artificial saliva solution by potentiostat (EG&G Co, PARSTAT 2273. USA ). Results: In as-casted and homogenized Ti-xZr alloys, α-phase was identified by XRD. Microstructures were changed from lamellar structure to needle-like structure as Zr content increased. From the results of anodic polarization behavior in the Ti-xZr alloys, it was found that the corrosion resistance was increased with increasing Zr content. From results of passivation stability test, current density of homogenized specimen(7.702×10-8 A/cm²) showed lower than that of as-casted specimen(3.483×10-7 A/cm²) with 1-order difference. Current density of Ti-40Zr decreased with increasing corrosion time. Conclusions: Consequently, in the Ti-xZr alloys, surface stability for biomaterials increased as Zr content increased.

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Journal: TechConnect Briefs
Volume: 2, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 2
Published: May 20, 2007
Pages: 725 - 728
Industry sector: Medical & Biotech
Topics: Biomaterials
ISBN: 1-4200-6183-6