Role of tantalum and nickel ion implantation on corrosion resistance properties of a Ti-Al-Zr alloy

Electrochemical behavior of Ti-Al-Zr implanted with nickel and tantalum ions and a co-implantation of them was investigated as a function of fluences. The polarization curves of the un-implanted and implanted Ti-Al-Zr were potentiodynamically measured in a hydrochloric acid solution. Electrochemical measurements revealed that nickel ion implantation significantly promoted the passivation of Ti-Al-Zr with an increase of fluence and the corrosion potentials resided in the passive region at fluences above 1 × 1016 ions/cm2. Tantalum ion implantation was effective in reducing the anodic current densities in the active and passive regions as fluences increased. On the other hand, the polarization curves of the co-implanted Ti-Al-Zr exhibited more stable passive behavior with low current densities. It was concluded that an excellent corrosion resistance of Ti-Al-Zr was achieved by complementary effects of nickel and tantalum ions co-implantation.