The effects of rare earth (RE) addition on the corrosion behavior of micro-alloyed steels in 3.5 wt.% NaCl solution were investigated elaborately through electrochemical tests and material characterization analyses. Results showed that the corrosion rate decreased after addition of RE elements. The RE elements did not alter the pitting nucleation mechanism, while the sensitivity of pitting propagation was reduced by decreasing the pitting density and pitting depth. In the long-term corrosion, preferential precipitation of RE corrosion products promoted the formation of protective rust layers and accelerated the co-deposition of these layers, which probably be favorable for the formation of compact rust layers. Moreover, the RE addition reduced the surface electrochemical activity and the adsorption tendency of Cl⁻ on the metal surface. As a consequence, the resistance of electrochemical reactions (represented by R_p values in EIS tests) increased, resulting in a decrease of corrosion rate by RE addition.

通过电化学测试和材料表征分析，详细研究了稀土（RE）对微合金钢在3.5 wt％NaCl溶液中的腐蚀行为的影响。结果表明，添加稀土元素后腐蚀速率降低。稀土元素并没有改变点蚀成核机理，而通过降低点蚀密度和点蚀深度降低了点蚀传播的敏感性。在长期腐蚀中，RE腐蚀产物的优先沉淀促进了保护性防锈层的形成并加速了这些层的共沉积，这可能有利于形成致密的防锈层。此外，稀土添加降低了表面的电化学活性和Cl的吸附倾向^-在金属表面上。结果，电化学反应的电阻（在EIS测试中用R _p值表示）增加，导致添加RE导致腐蚀速率降低。