Hastelloy合金在NdF_(3)-LiF熔盐环境中的耐蚀性研究

Corrosion Resistance of Hastelloy alloy in NdF_(3)-LiF Molten Salt Environment

阳极压板是稀土电解炉上的重要导电连接部分,目前稀土电解炉上使用的20钢阳极压板的寿命很短,严重制约生产。在20钢的基础上引入系列Hastelloy合金进行高温NdF_(3)-LiF熔盐环境腐蚀实验,并通过扫描电子显微镜、能谱和失重、减薄分析探讨四种材料的腐蚀规律。结果表明,20钢在1小时内就已开始腐蚀,而Hastelloy合金却是在5~10小时后才开始腐蚀。实验时间达到150小时后,20钢的减薄量为1.222 mm;Hastelloy-B合金为0.104 mm;Hastelloy-N合金为0.073 mm、Hastelloy-C合金为0.090 mm。四种材料的腐蚀过程为20钢从表面向内部的均匀腐蚀,Hastelloy系列合金均为均匀和晶界腐蚀,且腐蚀产物分别是F、O与Fe和F、O与Ni、Cr和Mo所组成的相。若以失重量为依据,经理论计算得出四种材料的减薄速率,20钢为9.65 mm/mon,而Hastelloy-B为0.806 mm/mon,Hastelloy-N为0.511 mm/mon,Hastelloy-C为0.691 mm/mon。系列Hastelloy合金的耐腐蚀性分别是20钢的11.96、18.87和13.96倍。

The anode plate is an important conductive connection part in rare earth electrolytic furnace.At present,the life of the steel 20 anode plate used in rare earth electrolytic furnace is very short and severely restricts production.In this experiment,a series of Hastelloy alloys was introduced on the basis of steel 20 for high temperature NdF_(3)-LiF molten salt environmental corrosion experiments.The corrosion laws of four materials were investigated by scanning electron microscopy,energy spectrum,weight loss and thinning analysis.The results show that steel 20 has started to corrode within 1 hour,while Hastelloy did not start to corrode in 5~10 hours.After the experimental time reached 150 hours,the thickness reduction for steel 20,Hastelloy-B,Hastelloy-N and Hastelloy-C was 1.222 mm,0.104 mm,0.073 mm and 0.0899 mm,respectively.Uniform corrosion of steel 20 from the surface to the inside was confirmed.But uniform grain boundary corrosion for Hastelloy series alloys was determined.The phases of corrosion products on steel 20 and Hastelloy series alloys are composed of F,O and Fe,and F,O,Ni,Cr and Mo,respectively.The thinning rates for steel 20,Hastelloy-B,Hastelloy-N and Hastelloy-C were calculated as 9.650 mm/mon,0.806 mm/mon,0.511 mm/mon and 0.691 mm/mon,respectively.The values of corrosion resistance for Hastelloy-B,Hastelloy-N and Hastelloy-C are 11.96,18.87 and 13.96 times of 20 steel,respectively.