目的 研究变形量对 690 合金电化学行为的影响。 方法 采用动电位极化、电化学阻抗和高温高压浸泡实验,结合扫描电子显微镜(SEM)、X 射线光谱仪(EDX)和 X 射线光电子能谱(XPS),研究不同变形量的 690 合金传热管在核电模拟液中的腐蚀行为。 结果 在常温常压下,50% 变形量试样的自腐蚀电位比 25% 变形量试样正 140 mV,维钝电流密度显著降低,阻抗模值高出约 10 倍。 高温高压下浸泡后,XPS 分析显示,50% 变形量试样表面腐蚀产物膜中的 Cr2O3 含量远高于 25% 变形量试样,其富 Cr 内层致密,氧化层更厚。 结论 50%变形量的 690 合金表面形成的钝化膜及腐蚀产物膜对基体的保护作用更强。

Objective To study the effect of rolling deformation on the electrochemical behavior of 690 Alloy. Methods Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and high temperature and pressure immersion tests, combined with scanning electron microscopy (SEM), X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) techniques, were used to investigate the corrosion behavior of 690 alloy heat transfer tubes with different degrees of deformation in the nuclear simulation solution. Results Under the atmospheric pressure, the corrosion potential of 690 alloy with 50% deformation was 140 mV larger than that of 690 alloy with 25% deformation. Furthermore, the passive current density of the former was significantly declined and the impedance modulus was 10 times higher. After soaking at high temperature and high pressure, XPS results showed that when the experiential materials were immersed for 200 h, 690 alloy with 50% deformation had a higher Cr2 O3 content in the corrosion product film than 690 alloy with 25% deformation, and its dense inner layer of Cr-rich oxide film was much thicker. Conclusion The passivation film and corrosion products layer formed on the surface of alloy 690 with 50% deformation had a better protective effect on the substrate.