【作者】 杨勇；

【导师】 张金柱；

【作者基本信息】 贵州大学 ， 材料学， 2017， 硕士

【摘要】 近年来各领域对稀土元素的应用研究越来越多。其中钕在自然界中存量丰富,居稀土元素中第二位。对推动稀土产业发展,尤其是促进稀土在高新技术领域中的应用,发挥着极为重要的作用。系统研究钕、铁、砷的相互作用产物,对研究Nd-Fe-As三元系的生成物具有有重要的指导意义。本研究将钕和砷按不同原子配比(1:2.5,1:3,1:3.5,1:4),加入到自制的H08钢缸体中,升温至不同温度(900℃,950℃,1000℃)保温至不同时间(5h,30h,50h)制成样品。采用X射线衍射、扫描电镜、能谱、金相显微镜等分析测试方法,结合对Nd-Fe-As体系相关扩散参数的计算,研究密闭条件下的钕铁砷相互作用规律。并得出如下结论:不同钕砷原子配比对该体系的组织均匀程度有较为明显的影响。在钕砷原子配比为1:3时,Nd-Fe-As高温体系的产物主要有NdFeAs,NdAs,Fe2As和Nd2Fe17,并且组织均匀程度相对于其他钕砷配比较高。随着保温温度的提升,结合对金相,物相以及背散射电子像的分析可以判断该体系三元化合物NdFeAs的相对含量逐渐降低,且NdFeAs的生成在900℃至950℃这个温度区间较容易生成,保温温度为900℃时Nd-Fe-As高温体系的产物主要有NdFeAs、NdAs、Fe2As和少量的Nd2Fe17。保温时间的长短直接影响到Nd-Fe-As体系生成物,随着保温时间的加长,该体系组织均匀程度提高。长时间的保温可能导致生成产物NdFeAs的分解,其中在保温时间为30小时Nd-Fe-As高温体系的产物组织均匀度相对较高,其产物主要有NdFeAs、NdAs和Fe2As,另外还含有少量Nd2Fe17。经过相关扩散参数的计算发现,在Nd-Fe-As高温体系中,Fe原子的扩散占据主导地位。更多还原

【Abstract】 In recent years,the study on application of rare earth elements in various fields is more and more on focus.The neodymium in nature is abundance in the Earth’s crust.However,rare earth neodymium is one of the most functional elements.To promote the development of rare earth industry,particularly in the high-tech field applications of rare earths,neodymium plays a very important role.Systematic study of the interaction products between neodymium and arsenic shows an important guiding significance for the deformation of the ternary Nd-Fe-As.In this paper,neodymium and arsenic are mixed in the H08 steel cylinder according to various atom ratio(1:2.5,1:3,1:3.5,1:4),temperature(900℃,950℃,1000℃)and insulation time(5h,30 h,50h).By means of XRD,SEM,EDS and metallographic microscope analysis,combining with the calculation of the related diffusion parameters in Nd-Fe-As system,the interaction law among neodymium,iron and arsenic was studied in closed vessel.And comes to the conclusions as follows.The various atom ratios of neodymium and effect obviously on diffution uniformity of the system.When the atom ratio of neodymium and arsenic was 1:3,the products of Nd-Fe-As ternary at high temperature mainly include NdFeAs,NdAs,Fe2 As and Nd2Fe17,and its uniformity is higher than that of other neodymium and arsenic ratio.Insulation temperature for Nd-Fe-As ternary is one of the necessary conditions of reaction.With the insulation temperature went up,ternary relative content of compound NdFeAs gradually reduce,while ternary compound Nd Fe As generated easily at the temperature range between 900℃ and 950℃.When the insulation temperature was 900℃,the product of Nd-Fe-As ternary at high temperature mainly include NdFe As,NdAs,Fe2 As and a spot of Nd2Fe17.The insulation time directly affects the products of Nd-Fe-As system.With the rising up,homogeneity degree of the structure went up.Too long holding time can also lead to the decomposition of the product NdFeAs.When insulation time is 30 h,homogeneity degree of the structure is relatively high.The product of Nd-Fe-As ternary at high temperature mainly include NdFeAs,NdAs,Fe2 As and a spot of Nd2Fe17.It is found that diffusion of Fe atoms is dominant in the Nd-Fe-As high temperature system according to the calculation of the related diffusion parameters.更多还原