Zr₅₆Cu₁₉Ni₁₁Al₉Nb₅非晶合金的腐蚀行为

The corrosion behaviors of Zr₅₆Cu₁₉Ni₁₁Al₉Nb₅ metallic glass in 3.5% NaCl, 1 mol/L NaOH and 1 mol/L H₂SO₄ solutions were analyzed by immersion test, potentiodynamic polarization test, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy. Immersion tests reveal that when the samples are immersed in 3.5% NaCl, 1 mol/L NaOH and 1 mol/L H₂SO₄ solutions for 2 256 h, absence of obvious corrosion can be observed by naked eyes. SEM results show that the localized corrosion behavior occurs in the samples, where the corrosion resistance is presented as follows: the worst in 3.5% NaCl solution, the middle in 1 mol/L NaOH solution, and the best in 1 mol/L H₂SO₄ solution. Potentiodynamic polarization tests indicate that absence of passivation occurs in 3.5% NaCl solution, and passivation film is dissolved locally due to the attack of Cl^-. The corrosion current density reaches the highest value in 3.5% NaCl solution, indicating the worst corrosion resistance. Passivation with the formation of dense and stable passivation film occurs in 1 mol/L NaOH and 1 mol/L H₂SO₄ solutions. In 1 mol/L H₂SO₄ solution, the spontaneous corrosion potential and the pitting potential reach higher values desirable effect, and the corrosion current density is the smaller with the wider passivation region, so more stable passivation film provides better protection, indicating better corrosion resistance. EDX and XPS analysis shows that in 3.5%NaCl, 1 mol/L NaOH and 1 mol/L H₂SO₄ solutions, the corrosion products are mainly composed of ZrO₂, Cu₂O, Al₂O₃, NiO and Nb₂O₅.