稀土Y对低合金钢耐蚀性的影响研究  

Influence of Rare Earth Element Y on the Corrosion Resistance of Low Alloy Steel

作　　者：孟祥超 刘香军[1] 祝英杰 富晓阳[1] 杨昌桥[1] 杨吉春[1] MENG Xiangchao;LIU Xiangjun;ZHU Yingjie;FU Xiaoyang;YANG Changqiao;YANG Jichun(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《材料保护》2024年第8期47-57,167,共12页Materials Protection

基　　金：国家自然科学基金(52204364,52364044);内蒙古自治区直属高校基本科研业务费项目(2023QNJS011);中央引导地方科技发展资金项目(2022ZY0090)。

摘　　要：为了研究稀土Y对低合金钢耐腐蚀性能的影响,通过向DH36低合金钢中添加稀土Y,得到不同稀土含量的低合金钢,采用3.5%NaCl溶液作为腐蚀介质,模拟海洋环境对DH36船板钢耐腐蚀性能的影响。采用浸泡实验、激光共聚焦显微镜、扫描电镜(SEM)、X射线衍射分析仪(XRD)、电化学测试等方法来考察稀土Y对DH36船板钢耐腐蚀性能的影响,并采用电子背向散射衍射(EBSD)来探究未被稀土改性的夹杂物和稀土夹杂与钢基体之间的残余应力大小,进而判断夹杂物对低合金钢耐蚀性能的影响。结果表明:稀土可以细化晶粒、改性夹杂物,减少稀土夹杂物的周边应力,减少微裂纹与微孔洞的发生,进而降低低合金钢在模拟海洋环境中的腐蚀敏感性;Y的加入可以使腐蚀电位正移,减小腐蚀电流密度,减少腐蚀初期试验钢表面点蚀坑的出现,进而减小腐蚀发生的活性区;此外,稀土Y的添加使腐蚀产物中γ-FeOOH的含量显著减少,Fe_(3)O_(4)和α-FeOOH的含量增加,锈层的稳定性与致密性增强;Y的添加还使锈层厚度变大,更有效地阻碍Cl^(-)的进入。稀土Y的添加可以有效提高低合金钢的耐蚀性能,当稀土质量分数为0.0043%时,试验钢的耐蚀性最好。To study the effect of rare earth Y on the corrosion resistance of low alloy steel,low alloy steel with different rare earth contents was obtained by adding rare earth Y to DH36 low alloy steel.Then,the effect of simulated marine environment on the corrosion resistance of DH36 ship plate steel was investigated using 3.5%NaCl solution as the corrosive medium.The effects of rare earth Y on the corrosion resistance of DH36 steel were investigated using immersion tests,laser confocal microscopy,scanning electron microscopy(SEM),X-ray diffraction analy-zer(XRD),electrochemical testing and other methods.The residual stress between inclusions unmodified by rare earth and inclusions modified by rare earth and the steel substrate was investigated using electron backscatter diffraction(EBSD),and the effect of inclusions on the corro-sion resistance of low alloy steel was determined.Results showed that rare earths could refine grains,modify inclusions,reduce the peripheral stress of rare earth inclusions,reduce the occurrence of microcracks and micropores,and thus reduce the corrosion sensitivity of low alloy steel in simulated marine environments.The addition of Y could shift the corrosion potential positively,decrease the corrosion current density,and reduce the appearance of pitting pits on the surface of the test steel in the early stage of corrosion,thereby reducing the active area where corro-sion occurred.Moreover,the addition of rare earth Y significantly declined the content ofγ-FeOOH in the corrosion products,increased the content of Fe_(3)O_(4)andα-FeOOH,and enhanced the stability and compactness of the rust layer.Furthermore,the addition of Y also increased the thickness of the rust layer,more effectively hindering the entry of Cl^(-).Hence,the addition of rare earth Y could effectively improve the cor-rosion resistance of low alloy steel.When the mass fraction of rare earth was 0.0043%,the best corrosion resistance of the test steel was achieved.

关 键 词：稀土Y 夹杂物 DH36低合金钢 耐蚀性 电化学 腐蚀产物 

分 类 号：TG172[金属学及工艺—金属表面处理]