Thermal Stability and Corrosion Behavior of Ni-Ti(-Zr)-P Glassy Alloys

Abstract:

Ni76Ti5P19 and Ni73Ti5Zr3P19 (at%) metallic glasses were prepared by a melt-spinning technique. Their thermal stability and corrosion behaviors were investigated, and the effects of Zr addition on the properties of the Ni-Ti-P glassy alloy were discussed. Results show that Zr addition increases the glass transition temperature (Tg) and crystallization temperature (Tx) of the Ni76Ti5P19 glassy alloy, and decreases its supercooled liquid region (ΔTx). Electrochemical tests in NaCl, HCl and H2SO4 solutions indicate passivation behavior of the Ni-Ti(-Zr)-P metallic glasses. Their good corrosion resistance can be attributed to the formation of a protective Ti/Zr- and phosphorus-rich layer on the surface of the alloys. Compared with Ni76Ti5P19 glassy alloy, the Ni73Ti5Zr3P19 glassy alloy exhibits higher open-circuit potential and lower passive current density. Partially replacing Ni with Zr in Ni-Ti-P alloy introduces ZrO2 in the passive film, which improves the protection of the surface film and results in a higher corrosion resistance