等离子体电弧熔炼法对金属铽中碳含量的影响  

Effect of Plasma Arc Melting Technology on Carbon Concentration in Terbium

作　　者：李国玲[1,2] 李里[1] 郭恒[3] 田文怀[2] 李星国[1] 

机构地区：[1]北京大学化学与分子工程学院稀土材料化学及应用国家重点实验室,北京100871 [2]北京科技大学材料科学与工程学院,北京100083 [3]清华大学物理工程系,北京100084

出　　处：《高电压技术》2015年第9期2925-2929,共5页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2012CBA01207)~~

摘　　要：高纯铽金属是镧系金属中应用较为广泛的重稀土元素,其中碳元素是金属提纯过程中较难脱除的小分子杂质元素之一。固溶的间隙杂质会对材料的物理化学性能产生不利影响。为此通过等离子体电弧熔炼技术对商用铽金属进行高温熔炼,采用红外测试技术标定熔炼前后金属中的碳含量。实验结果表明:高温等离子体可以脱出基体金属中残留的微量碳成分,并且不同等离子体氛围、熔炼时间及电流强度对铽金属中脱碳行为都有不同影响;其中,氢等离子体表现出更显著的脱碳效果,随着通入氢气量的增加金属中碳质量分数可降低至0.017 085%。氢气在高温发生电离,激发态的氢等离子体具有极高化学反应活性,在熔炼脱碳过程中发挥了重要作用。氢等离子体的热导率极高,可以提高熔融金属表面温度,促进杂质挥发。High-pure terbium is one of the most useful heavy rare-earth elements in lanthanide metal, while carbon is difficult to remove as a sort of small molecule during the refining process. The interstitial impurity can dramatically destroy the physicochemical properties of the materials. In this work, plasma arc melting （PAM） of commercial terbium was examined. The carbon concentration in terbium specimens before and after melting was examined by infrared testing technology. The results show that the plasma arc melting can significantly promote the decarburization of terbium, and different plasma gases, melting time, and electric current can affect the results to various degrees. Especially, the carbon concentration can reduce more efficiently with the hydrogen content increasing, the final carbon concentration is 0.017 085%. The hydrogen molecule can dissociate in high temperature, and the active hydrogen plasma with high chemical reactivity plays an important role during the whole melting process. Furthermore, the dissociated and activated hydrogen atoms can increase the surface temperature of molten metal due to the higher thermal conductivity, which can promote the impurities＇ evaporation.

关 键 词：等离子体电弧熔炼 氢等离子体 高纯化 铽 碳 化学反应热力学 

分 类 号：TF845[冶金工程—有色金属冶金] TF19