Study On The Die-upset Magnets Of Rare-earth-lean Nd-Fe-B Mixed Powder

In this paper,the mixed powder hot pressure/hot deformation magnets?HD magnets for short?were prepared by using the Nd_11.5Fe_81.8B_6.0Nb_0.7 and Nd_11.5Fe_77.5Co_5.0B_6.0,respectively,as well as0,3 wt%,6 wt%,9 wt%,and 12 wt%of Nd₆₇Cu₃₃ alloy.Studied 2:14:1 phase of NdFeB,the structure evolution process of?-Fe phase and the effects of the coercivity and the rare-earth-lean containing Co blending with Nd67Cu33 HD magnet with the increase of the proportion of added texture of magnet and coercivity of impact.Firstly,the powder was mixed with the rare-earth-lean Nd_11.5Fe_81.8B_6.0Nb_0.7 alloy and Nd67Cu33 alloy.The volume fraction V of Nd-Fe-B ternary phase diagram was calculated.The results showed that when the ratio of Nd67Cu33 was increased to 3wt%,and the?-Fe decreased from 1.11vol%to 0,the coercivity increased from 317kA/m to 626kA/m,with an increase rate of97.48%.It is found that the hot pressure/hot deformation magnetic body of the two-phase alloy with the?-Fe is 462⁶59kA/m lower than that of the mixed HD magnet.When the deformation amount increased to 30%,the Nd₆₇Cu₃₃ inhomogeneous diffusion process occurred in response to the?-Fe,and the partial occurrence of the rare-earth phase,and the percentage of the volume of?-Fe decreased gradually.In addition,When the deformation amount is 70%,the decrease of size is10¹5 nm,and the exchange coupling effect of double phase grains increases the coercivity.The deformation amount is more than 30%,and the Nd₂Fe₁₄B grain is grown from the isoaxial crystal to the flake crystal,and the coercivity is reduced.Nd₆₇Cu₃₃ to 0¹2 vol%,calculating mixed points of HD magnet Nd2Fe14B grain equivalent average grain size of 219²73 nm,coercivity from 317 to 893 kA kA/m,analysis found that the rich rare earth in the grain boundary by blending magnet volume Nd₆₇Cu₃₃ increased to 3 vol%,coerciveity fastest-growing its main reason is that?-Fe disappear,rich rare-earth volume percentage increase of grain boundary phase.In addition,the rare-earth-lean alloys containing Co were studied,including Nd_11.5Fe_77.5Co_5.0B_6.0 and 0,3 wt%,6 wt%,9 wt%,12 wt%of Nd₆₇Cu₃₃ and the alloy powder.Analysis found that poverty is the coarse grains in rare earth HD alloy,there is empty and those of rare-earth alloy mixed powder HD with the increase of the proportion of added Nd67Cu33,small grains by the massive isometric to flake crystal development.The HD magnet formed a good texture,and the magnetic remanence increased from 0.805T to 1.169T.However,the addition of Nd67Cu33 was increased from 0-6wt%,and the coercivity was continuously increased to 1070 kA/m,adding Nd67Cu33 to 12wt%,and the coercivity of mixed powder HD was continuously reduced to 685.85kA/m.