稀土对低碳钢耐大气腐蚀性能影响的研究

【作者】 李春艳；

【导师】 张代明； 刘清友； 王向东；

【作者基本信息】 昆明理工大学 ， 材料学， 2005， 硕士

【摘要】 稀土元素可以提高钢的耐大气腐蚀性能,但其中的作用机理尚不十分清楚,例如稀土对锈层形成过程、对锈层结构的影响及稀土在腐蚀产物中的最终存在形式等问题。为进一步研究稀土对钢耐大气腐蚀性能影响及探讨稀土提高钢耐大气腐蚀性机理,本文采用四种不同稀土含量的低碳钢,利用实验室加速腐蚀试验—周期浸泡试验和盐雾试验方法和电化学试验方法,观察和分析了不同加速腐蚀试验时间试验钢的锈层形貌、锈层构成、锈层致密性、腐蚀后稀土的存在方式和计算了不同加速腐蚀试验时间试验钢的腐蚀率,并测量和计算了未经加速腐蚀试验的试验钢的腐蚀率。 研究结果表明:①在模拟Cl^-环境中,稀土对低碳钢的耐蚀性能影响不显著;仅高稀土含量低碳钢（0.12%RE）的耐蚀性一直好于不含稀土低碳钢（0.0%RE）。四种试验钢锈层非常疏松、粘附性小、保护性很小。②在模拟工业大气环境中,稀土能明显地提高低碳钢的耐大气腐蚀性能。经288小时周期浸泡试验后,高稀土含量低碳钢（0.12%RE）腐蚀率比无稀土低碳钢（0.0%RE）腐蚀率降低32%。③在模拟工业大气环境中,稀土促进γ-FeOOH/γ-Fe₂O₃向稳定的保护性α-FeOOH转变,从而提高了锈层的粘附性及致密性。更多还原

【Abstract】 Rare Earth（RE） elements could improve the atmospheric corrosion resistance properties of steels, but the effective mechanism was not clear and there were not yet enough evidence to show how the RE to affect on the forming process and the structure of the rust layer,and what is the ultimate state of RE in the rust layer. In this paper, indoor accelerating corrosion test—alternate immersion corrosion test and salt spray test,and electrochemistry test were designed to investigate the role of RE on improving atmospheric corrosion resistance of steels and to research the mechanism why the addition of RE could improve atmospheric corrosion resistance of steels. The morphologies, composing and compactness of the rust layer have been observed and analyzed after different time of indoor accelerating corrosion test,the corrosion rate has been calculated after different time of indoor accelerating corrosion test,and the corrosion rate of tested steels at non-accelerating corrosion test has been tested and calculated to provide comparison and analysis.The research results have shown that: （1）In Cl- environment simulation condition, the addition of RE in steels could not evidently improve the corrosion resistance of mild steels, while the corrosion resistance of mild steel containing 0.12%RE was always better than that of mild steel without RE after different times fog corrosion test. On this condition, the rust layer of tested steels was very loose, less adhesive and non-protective. （2）In industrial environment simulation condition, the addition of RE could remarkably improve atmospheric corrosion resistance of mild steels, and the corrosion rate of mild steel containing 0.12%RE was 32% lower than that of mild steel without RE after 288 hours alternate immersion corrosion test. （3） In industrial environment simulation condition, RE promote the transition of the corrosion product from γ-FeOOH/γ-Fe₂O₃ to stable and protective a-FeOOH so that RE improved the adhesive and compactness of the rust layer.更多还原