退火温度对Zr₅₆Cu₁₉Ni₁₁Al₉Nb₅非晶合金电化学性能的影响

The effects of annealing temperature on the electrochemical properties of Zr₅₆Cu₁₉Ni₁₁Al₉Nb₅ metallic glass in 3.5% NaCl solution were investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS). DSC results show that at the heating rate of 10 K/min, the glass transition temperature T_g is 689.0 K and the crystallization temperature T_x is 733.3 K. XRD and SEM results reveal that the as-cast sample and the samples annealed at 623 K and 723 K for 30 min present amorphous structure and ones annealed at 823 K and 923 K are crystallized with higher crystallization degree at higher annealing temperature. Potentiodynamic polarization tests and EIS show that for the as-cast samples and the samples annealed at 623~923 K for 30 min, with the increase of the annealing temperature, the spontaneous corrosion potential is increased firstly and then decreased, and the corrosion current density is decreased firstly and then increased, while the radius of capacitance impedance is increased firstly and then decreased. It is indicated that the corrosion resistance is increased firstly and then decreased, with the best for the sample annealed at 723 K and the worst for the sample annealed at 923 K.