稀土在热浸镀铝中的行为和分布研究

Behavior and Distribution of Rare Earths in Hot Dip Aluminizing

分别在工业纯铁和20碳钢上制备了热浸镀纯铝和稀土铝镀层,采用扫描电镜(SEM)观察了镀层横截面和表面的形貌,采用能谱仪(EDS)和电子探针(EPMA)分析了镀层横截面的稀土分布。结果表明,添加稀土热浸镀铝后,表面层厚度减少,合金层厚度增加;镀层表面比较平整、连续、无裸露点、裂纹和氧化物夹杂,且FeAl3相短而细小;稀土渗入了镀层,且分布很不均匀,在部分区域存在偏聚,表面层与合金层界面处以及齿状Fe2Al5相的边缘处和齿尖处稀土含量较高。分析了稀土对镀层厚度和组织形貌的影响及稀土的渗入机理。

Pure aluminized coating and rare earths aluminized coating on 20 carbon steel are prepared by hot dip aluminizing method at 740℃ ,respectively. The structural form of the cross- section and surface morphology in the coatings are observed by scan- ning electronic microscopy （SEM） and the distribution of rare earths elements（RE）in the coatings was analyzed with energy disperse spectroscopy （EDS） and electron probe microanalyses （EPMA）. The results show that,after hot dip aluminizing with rare earths,the thickness of surface layer reduces and the thickness of alloy layer increases;the surface of aluminized coating is more neat and contin- uous;rare earths elements permeate alloy layer, its distribution is very asymmetry, and there is gather in partial district. The perme- ation and influence mechanism of rare earths elements are also discussed.