Thermal stability, corrosion resistance and nano-indentation behavior of Ni60Nb40-XZrX (X= 0, 20, 40) amorphous alloys

In this research, thermal stability, corrosion performance, hardness (H), and Young modulus (E) of Ni60Nb40, Ni60Nb20Zr20, and Ni60Zr40 amorphous ribbons were evaluated during the differential scanning calorimetry (DSC), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests, and nanoindentation technique, respectively. Results showed that the onset crystallization temperatures (To) of Ni60Nb40, Ni60Nb20Zr20, and Ni60Zr40 amorphous ribbons were 632 °C, 593 °C and 476 °C, respectively. It is determined that the higher Nb content increases the thermal stability against crystallization. Evaluation of corrosion resistance during potentiodynamic polarization test showed the polarization resistance value of 936 , 49, and 16 MΩ.cm2 for Ni60Nb40, Ni60Nb20Zr20, and Ni60Zr40 alloys, respectively. These results imply that the substitution of Zr with Nb enhances the thermal stability and corrosion resistance of Ni-Nb-Zr amorphous ribbons. Moreover, the H and E for Ni60Nb40, Ni60Nb20Zr20, and Ni60Zr40 amorphous ribbons were 171.3 and 15.01 GPa, 160.41 and 12.16 GPa, and, 188.52 and 14.13 GPa, respectively. It means complete substitution of Zr by Nb in Ni-Nb-Zr amorphous ribbons shows the highest hardness which is related to the Ni60Nb40 amorphous ribbon.