鈷鎳合金化球墨鑄鐵管件材料之腐蝕行為研究

Study on Corrosion Behavior of Cobalt and Nickel Alloyed Ductile Irons for Pipe Applications

陳明禮(M .L. Chen) ； 許正勳(C. H. Hsu) ； 吳建國(J. K Wu)

《鑄造工程學刊》 35卷2期 (2009/06) Pp. 20-27

https://doi.org/10.29809/JTFS.200906.0003

摘要

球墨鑄鐵一般常被使用於管件材料，然而球墨鑄鐵管材有鐵系材料之腐蝕問題。本研究即針對球墨鑄鐵材質改良，嘗試選擇以週期表中與鐵元素位置相鄰近的元素鈷、鎳合金元素後，進一步觀察其顯微組織、進行機械性能測試、極化及浸漬硫酸溶液腐蝕試驗比較。由實驗結果顯示：添加鈷元素合金後，球墨數增加，使基地為均質的肥粒鐵組織，硬度雖略差、但延韌性較佳；添加鎳元素合金化後，球墨數減少，使基地變為交互層狀的波來鐵組織，延韌性較差、但硬度較佳；然而因波來鐵組織為肥粒鐵與雪明碳鐵層狀結構，故產生伽凡尼效應的腐蝕現象較多；而組織均質的肥粒鐵基地，產生伽凡尼效應的腐蝕現象較少，耐蝕效果較佳。可做為球墨鑄鐵管件材質之改良。

關鍵字

延性鑄鐵 ； 鈷 ； 鎳 ； 腐蝕

並列摘要

It is known that ductile iron is often used for the pipe application, but it has a disadvantage of the poor corrosion resistance due to belonging to ferrous material. This study adopted the ductile irons alloyed with cobalt and nickel elements as experimental materials, and then microsrtuctural observation, mechanical tests, polarization and immersion tests were all performed. The main aim was to explore the relationship among microstructure, mechanical property, and corrosion behavior of the irons. The results showed that the iron with Co addition had the more nodule count and most ferrite in the microstructure, and better toughness but lower hardness. In contrast, the iron with nickel addition had the less nodule count and most pearlite in the microstructure, and better hardness but lower toughness. In the case of corrosion behavior, Galvanic corrosion of the Ni-alloyed iron was more serious than that of the Co-alloyed one. It denotes that the latter is superior to the former in corrosion resistance.

並列關鍵字

Ductile iron ； Cobalt ； Nickel ； Corrosion