CeO_2改性渗铝层及其氧化性能研究

Microstructure and oxidation behavior of novel CeO_2-modified aluminizing coating

低碳钢上复合电镀Ni-CeO2后,经过900℃扩散渗铝6h后制备CeO2改性的渗铝层,用相同工艺在低碳钢、单镍镀层上直接渗铝作为对比,进行了各种渗层在900℃下的氧化性能实验。实验结果表明,CeO2改性的渗铝层的氧化增重量较小,说明其抗氧化性能较好。利用电子显微镜及金相显微镜对氧化后的试样进行分析表明,三种渗铝层在氧化后表面都能形成氧化铝膜,而CeO2的渗铝试样氧化后表面的颗粒细小均匀,氧化铝膜薄而致密。

A novel CeO2-modified aluminizing coating was developed on a mild carbon steel with Ni-CeO2 electrodeposition. Then aluminizing on the Ni-CeO2 composite coating was conducted using pack cementation method at 900℃ for 6h. For comparison, aluminizing on the low carbon steel with and without electrodeposition of Ni was also conducted in the same condition. The oxidation behavior at 900℃ shows CeO2-modified aluminizing coating has lower mass gain. This indicates it has better oxidation resistance. Samples after oxidation were investigated using scanning electron microscopy （SEM） and optical microscopye （OM）. The restdts indicate that although all three coatings grow alumina scales during oxidation, the one formed on the CeO2-modified aluminizing coating is thinner, denser and has a fin-grain structure.