稀土Y对热浸镀铝镀层组织及耐蚀性的影响  

Influence of Rare Earth Yttrium on the Structure and Corrosion Resistance of Hot-dip Aluminum Coating

作　　者：刘艺 李国喜 郑毅然 LIU Yi;LI Guo-xi;ZHENG Yi-ran(School of Materials Science and Engineering,Northeastern University,Shenyang 110000,China)

机构地区：[1]东北大学材料科学与工程学院,沈阳110000

出　　处：《表面技术》2021年第9期286-292,共7页Surface Technology

摘　　要：目的研究稀土Y对热浸镀铝层的影响,提高热浸镀铝件的耐蚀性能。方法通过向热浸镀铝液中添加不同量的铝钇合金,获得稀土Y含量不同的热浸镀铝件。选用3.5%的NaCl溶液为腐蚀溶液,利用SEM、EDS观测其形貌、成分,并使用电化学测试和全浸试验研究稀土Y对镀层耐蚀性能的影响。结果当添加0.2%Y时,热浸镀铝层表面平整、无孔洞,针状相细小,镀铝层减薄,过渡层由锯齿状转变为连续带状。稀土Y的添加使镀铝件的自腐蚀电位正移,自腐蚀电流密度减小,添加量为0.2%时,自腐蚀电位最正,为-0.7857 V,自腐蚀电流密度最小,为1.3505×10^(-8) A/cm^(2)。与添加其他稀土元素相比,添加0.2%Y时,镀层的破裂电位Eb最正,为-0.6957 V。不同稀土含量的热浸镀铝件的交流阻抗谱都为单一的容抗弧,当稀土Y添加量为0.2%时,容抗弧半径最大。全浸试验中,添加0.2%Y的镀件的腐蚀速率最低。结论稀土Y的添加可以使热浸铝层光滑、连续,且具有提高其耐腐蚀性的作用。Y添加量为0.2%时,镀铝件的耐蚀性最好。The work aims to study the influence of rare earth Y on the hot-dip aluminum coating and improve its corrosion resistance.By adding different contents of aluminum-yttrium alloy to the hot-dip aluminum coating solution,hot-dip aluminum-coated parts containing different rare earth yttrium content were obtained.In the experiment,the corrosion solution was 3.5%NaCl solution.SEM and EDS were used to observe morphology and composition and electrochemical tests and full immersion tests were used to study the effect of rare earth Y on corrosion resistance of coatings.When the content of Y was 0.2%,the surface of the hot-dip aluminized layer was smooth without holes,the needle-like phase was fine,the aluminized layer was thinner,and the shape of transition layer changed from the sawtooth to the continuous band.The rare earth Y made the corrosion potential shift positively and decreased the self-corrosion current,which the most positive self-corrosion potential was-0.7857 V and the minimum self-corrosion current was 1.3505×10^(-8) A/cm^(2).Compared with other rare earth elements,the breakthrough potential Eb of the coating,when 0.2%Y was added was,the most positive potential is-0.6957 V.The impedance spectroscopies of hot-dip aluminized parts with different rare earth contents were all single capacitive reactance arcs.The radius of the capacitive reactance arc was the largest when the rare earth content was 0.2%Y and the corrosion rate of coated parts was the lowest when 0.2%Y was added in the full immersion test The addition of rare earth yttrium can make the surface of the hot-dip aluminum coating smooth and continuous,and the corrosion resistance can be improved.Furthermore,the corrosion resistance of aluminum-coated parts is the best when the addition amount is 0.2%Y.

关 键 词：热浸镀铝 微观组织 耐蚀性 稀土Y 电化学方法 全浸试验 

分 类 号：TG174.4[金属学及工艺—金属表面处理]