目的 研究合金元素含量对材料耐蚀性能的影响。方法 通过动电位极化、电化学阻抗谱、ACM传感器以及化学浸泡研究了合金元素Cr、Mo、Sn对低合金钢在模拟热带海洋大气环境中腐蚀行为的影响，并通过扫描电子显微镜和X-射线衍射对腐蚀形貌、锈层结构进行表征。结果 当Cr元素含量为3%(质量分数)时，材料的耐蚀性能越好，这是由于Cr元素可以促进具有保护性能的腐蚀产物的生成来提高低合金钢的耐蚀性能。然而，含Cr低合金钢表面存在大量口径小深度大的腐蚀孔，表明材料容易发生局部腐蚀。为了增强含Cr低合金钢耐局部腐蚀能力，分别加入0.1%(质量分数)Mo、0.1%(质量分数)Sn，并同时加入0.1%(质量分数)Mo和0.1%(质量分数)Sn制备了3种低合金钢。根据ACM传感器数据曲线及腐蚀形貌图，发现Mo和Sn元素可以有效降低局部腐蚀的发生，同时含有Mo和Sn 2种元素的试样表面都是口径大深度浅的腐蚀坑。此外，Mo元素和Sn元素不仅可以提高材料自身的腐蚀性能，还可以增强腐蚀产物膜的保护性能。与3Cr低合金钢动电位极化曲线相比，Mo元素和Sn元素可以分别使材料的自腐蚀电流密度下降18%和51%，同时加入Mo、Sn 2种元素可以使自腐蚀电流密度降低71%。根据ACM传感器数据，3Cr钢腐蚀产物膜的缓蚀率为53.12%，Mo元素和Sn元素使腐蚀产物膜的缓蚀率分别提升至58.62%和73.91%。结论 在含3%(质量分数)Cr钢的基础上同时加入Mo和Sn元素可以获得耐蚀性能优异的低合金钢。

The work aims to study the effects of alloying elements Cr, Mo and Sn on the corrosion behavior of low alloy steel in simulated tropical marine atmosphere by potentiodynamic polarization, electrochemical impedance spectroscopy, chemical immersion experiment and ACM sensor. The corrosion morphology and rust layer structure were characterized by scanning electron microscope (SEM) and X-ray Diffraction (XRD), and the effect mechanism of alloying elements on corrosion resistance was discussed. The corrosion resistance of the material was the best when the content of Cr was 3wt.%. After different immersion periods, the surface of 3# (3Cr) low alloy steel primarily showed bulk particles with flocculent particles in some areas. The addition of Cr refined the particles within the rust layer, enhancing its density and inhibiting the penetration of corrosive media, thus improving corrosion resistance. Additionally, the main phases in the rust layer were α-FeOOH, γ-FeOOH and Fe3O4, and the increasing Cr content led to a decrease in Fe3O4 content within the rust layer. However, the surface of Cr-containing low alloy steel exhibited numerous deep corrosion holes in small diameter, indicating a susceptibility to localized corrosion. In order to enhance the local corrosion resistance of Cr-contained low alloy steel, three kinds of low alloy steel were prepared by incorporating 0.1wt.%Mo, 0.1wt.%Sn and 0.1wt.%Mo and 0.1wt.%Sn at the same time. Combined with the data curve of ACM sensor and the corrosion microtopography, it was found that Mo and Sn effectively reduced the occurrence of local corrosion, resulting in shallower corrosion pit of large diameter on the sample surfaces. Compared with the potentiodynamic polarization curve of 3# (3Cr) low alloy steel, the addition of Mo and Sn decreased the self-corrosion current density by 18% and 51% respectively, while the simultaneous addition of both elements reduced it by 71%. Moreover, the data obtained from the ACM sensor revealed that the corrosion inhibition rates of the 3Cr steel corrosion product film were 53.12%, 58.62%, and 73.91% for Mo, Sn, and the combined addition of Mo and Sn respectively. Furthermore, the Mo and Sn not only enhanced the corrosion resistance of the material itself but also improved the protective performance of the corrosion product film. Based on the results obtained from immersion tests of different periods, it was evident that the addition of Mo resulted in a relatively loose outer layer of the rust layer, while the addition of Sn did not exhibit any significant products on the surface of the rust layer. When both Mo and Sn are added simultaneously, the corrosion products on the steel surface are complete, the rust layer is dense, and no loss of corrosion products is observed. In the low alloy steel with Mo and Sn, the main phase components of the rust layer are α-FeOOH and γ-FeOOH. In conclusion, the addition of Mo and Sn to Cr steel can yield low alloy steel with excellent corrosion resistance.