Study On High Temperature Products Of Nd-Fe-As System

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.