Study Of The Corrosion Behavior Of The New Rare-earth Nickel-copper Alloy Cast Iron In Caustic Soda Solution

The resource of the natural soda is abundant in Inner Mongolia. However, thecorrosion problem of equipments is very serious in the caustic soda production, whichmakes the metal materials consume and affects the production. It is urgent to develop newtypes of materials of corrosion resistance.In the present work, the corrosion behavior was researched on Ni-Cu and RE-Ni-Cucast iron alloys in the caustic soda solution and the corrosion rate and soda corrosionresistance properties were tested by the methods of dynamic and static weight-loss at hightemperature. The corrosion surface of cast iron alloys was analyzed by the means of SEMand EDM. Moreover, the corrosion mechanism of the cast iron alloys in the caustic sodasolution and the functional mechanism of Cu, Ni and RE alloy elements were discussed.The results show that the corrosion type of the cast iron alloys is the uniform. Ni andCu are enriched on the surface in the process of corrosion. The corrosion levels ofN4(1.9%Cr, 16%Ni, 5%Cu) and N5(1.9%Cr, 20%Ni, 5%Cu) are grade 7 and 5respectively. The corrosion resistance properties are improved evidently with RE addedinto the cast iron alloys. The corrosion rate of R1(0.039%RE, 9.8%Ni, 5%Cu)is lower 32%than that of the cast iron alloy without RE. Low cost and excellent soda corrosionresistance properties of the cast iron alloys are gained by the suitable alloyed methods. Thecost is reduced and the economy benefit is obtained while the corrosion resistanceproperties of the cast iron alloys are guaranteed through applying the new types of cast ironalloys.