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分别在3.5%NaCl溶液、3.5%NaCl+1.0%H2O2溶液和pH=12的3.5%NaCl溶液中进行动电位极化实验,研究2024 Al-Cu-Mg合金在不同热处理状态下的腐蚀行为。极化曲线表明,随着合金时效时间的延长,合金的腐蚀电位向负方向移动;向NaCl溶液中添加H2O2会使腐蚀电位正移;在pH=12的3.5%NaCl溶液中的极化曲线表现出明显的钝化现象。腐蚀试样表面表现为常见的腐蚀特征,但也有扩大的点蚀、晶间腐蚀现象出现。循环动电位极化曲线显示有宽的循环极化滞后环,不同的腐蚀模式表明合金的点蚀生长对合金的热处理状态敏感。通过显微组织分析,探讨了不同热处理状态下合金在不同NaCl溶液中的腐蚀机理。
The potentiodynamic polarization experiments were carried out in 3.5% NaCl solution, 3.5% NaCl + 1.0% H2O2 solution and pH = 12 3.5% NaCl solution respectively to study the corrosion behavior of 2024 Al-Cu-Mg alloy under different heat treatment conditions. The polarization curves show that the corrosion potential of the alloy moves in the negative direction with the extension of the aging time of the alloy. The addition of H2O2 to the NaCl solution causes the corrosion potential to shift positively. The polarization curve in 3.5% NaCl solution with pH = 12 A clear passivation phenomenon. Corrosion The surface of the sample shows common corrosion characteristics, but also has an enlarged pitting corrosion phenomenon. The cyclic potentiodynamic polarization curve shows a wide cyclic polarization hysteresis loop. Different corrosion modes indicate that the pitting growth of the alloy is sensitive to the heat treatment of the alloy. Through the microstructure analysis, the corrosion mechanism of the alloys in different NaCl solutions under different heat treatment conditions was discussed.