Fabrication And Property Research Of Ni-free Ti-based Amorphous Alloy

At present, Titanium-based amorphous alloy has gradually become more popular in biological materials due to its excellent mechanical porperties and good biological corrosion resistant performance. At this stage, Ti-based amorphous alloy has reported a variety of good performances, but most of them have some elements（Ni and Be,etc.）, which pose biological safety hazards. They also may contain some precious metal elements, such as Pd and Ag, etc. If after long-term implantation in the human body as biological material, these elements will cause harm to human body tissues and organs, excessive levels can be deadly. So it is necessary through composition optimization to improve the biological safety of Ti-based amorphous alloy, The goal is to be safe, cheap and reliable without reducing the glass forming ability of amorphous alloy, Make Ti-based amorphous alloy can truly applied in the field of bio-medical, to make due contribution to the healthy of human beings.As is well-known, Micro-alloying can not only improve the glass forming ability of amorphous alloy, but also improve its biological corrosion resistance. At present,research of Ti-based amorphous alloy and combined with micro-alloying in the application of titanium alloy materials is being used, in order to ensure good performance of Ni-free Ti-based amorphous alloy. Selection to Ti₄₀Cu₃₉Zr₁₀Ni₁₁ as master alloy, using cheap and good performance element Sn and Fe to add and replace toxic element Ni. Ti₄₀Cu₃₉Zr₁₀Ni₁₁-xMx（ M=Sn, Fe; x= 0,3,7,11 atom fraction/%）amorphous ribbons were prepared by melt-spinning. The effects of micro-structure and thermal stability on Sn and Fe element addition were respectively analyzed by X-ray diffraction（XRD） and differential scanning calorimeter（DSC）, their biological corrosion resistance were investigated by electrochemical test and scanning electron microscopy（SEM）. Finaly, Ni-free Ti40Cu39Zr10Sn11 and Ti40Cu39Zr10Fe11 amorphous alloy exhibit excellent corrosion resistant performance, XPS analysis was performed for the specimens which immersed for 168 h in PBS solution, and preliminary judgment the blood compatibility of two amorphous alloy. The results indicate that:（1） With Sn addition, Ti₄₀Cu₃₉Zr₁₀Ni₁₁-xSnx（x=0,3,7,11）alloy all exhibited pure amorphous structure, the addition of Sn the thermeal stability basically remain unchanged and biological corrosion resistance improved. For Ni-free Ti40Cu39Zr10Sn11 its surpercooled liquid region（DTx） about 37 K and glass forming ability（GFA） are also improved slightly. Good performance of bio-corrosion resistance is expressed incorrosion potential move to right and self-corrosion current density decreased.Ti40Cu39Zr10Sn11 has the widest passivation range and higer corrosion pontenial.（2） Compared with Sn addition, Ti₄₀Cu₃₉Zr₁₀Ni₁₁-xFex（x=0,3,7,11）alloy also exhibited pure amorphous structure. Their thermeal stability almost invariant, after Ni element was totally replaced by Fe, surpercooled liquid region of Ti40Cu39Zr10Fe11 have no change. Compared with mother alloy and Ti40Cu39Zr10Sn11, it has the higest corrosion potential and the widest passivation range. From the SEM image, pitting corrosion pit of Ti40Cu39Zr10Fe11 surface is less and shallow. Two kinds of Ni-free amorphous alloy all exhibited excellcent bio-corrosion resistance in the simulated body fluid.（3） X-ray photoelectron spectroscopy（XPS） virify the passive film is rich in TiO2 and Zr O2, Cu2 O has low content. This is the main cause of their corrosion resistance was improved. Meanwhile, Sn and Fe with higer oxidation states, can protect the passivation membrane on the surface of amorphous alloys from corrosion.Ti40Cu39Zr10Fe11 exhibit better bio-corrosion performance compared with Ti40Cu39Zr10Sn11, because it has poorer of PO43-. Finaly, two kinds of amorphous alloys all exhibit good blood compatibility by kinetic clotting and hemolysis.