| With the depletion of fossil fuels and human damage to the environment,the permanent magnet materials obtain enhancing attention as a medium for energy conversion in daily life,production and military industry.Anisotropic bulk SmCo5 rare earth permanent magnet materials have become one important candidate due to their excellent high-temperature stability.However,the saturation magnetization of SmCo5 magnets is low.The saturation magnetization of(Sm,Pr)Co5 magnets which prepared by replacing some Sm with Pr can be improved to some extent,thus improving their magnetic properties.In order to further improve the saturation magnetization and reduce the preparation cost,the researchers added Fe and Co to the(Sm,Pr)Co5 magnets.However,most of the magnets prepared at present are powder and do not have anisotropy.Therefore,it cannot meet people’s demand for block permanent magnet materials.To address this issue,this paper added Fe and FeCo to(Sm0.6Pr0.4)Co5 and prepared anisotropic nanocrystalline bulk magnets,and studied the effects of Fe and FeCo additions on the structure and magnetism of(Sm0.6Pr0.4)Co5 nanocrystalline permanent magnet materials.The specific research in this paper is as follows:Adding FeCo to(Sm0.6Pr0.4)Co5 amorphous precursor exhibits a higher degree of amorphization compared to adding Fe.After annealing at 580℃ for 10 minutes,the precursors with different amounts of Fe and FeCo added all contain(SmPr)Co3 phase,(Sm,Pr)Co7 phase,Fe phase.Fe and FeCo content ranging from 15wt.%growth to 26wt.%MS increased by 1.7kG and 2.8kG respectively;Hci decreased by 4.6 kOe and 6.4 kOe,respectively.(BH)max reached its peak at a content of 20%,reaching 8.8MGoe and 9.4MGoe.The amorphous precursor of(Sm0.6Pr0.4)Co5+20wt.%Fe and FeCo was deformed at Pmax=700 MPa and Tmax=550℃,which is similar to the phase transformation pattern in the two types of alloys after annealing at 650℃ to 800℃ for 2 minutes.At temperatures below 800℃,both contain(Sm,Pr)Co7 phase and(SmPr)Co3 phase,Fe phase.And the(Sm,Pr)Co7 content is higher when FeCo is added.At 800℃,the Fe phase and(SmPr)Co3 The phase disappears and(SmPr)Co5 and(SmPr)2Co17 phases appear.The grain size of both increases with increasing temperature,with peaks of 30nm and 22nm,respectively.The Hci of the two first increases and then decreases with the increase of temperature,and the peaks of adding Fe and FeCo appear at 7.8kOe at 700℃ and 10.3kOe at 750℃.Both Br‖/Br⊥increase with temperature,with maximum values of 1.3 and 1.9,respectively.When FeCo is added to the precursor,the magnet is more susceptible to stress induced texture formation than when Fe is added.A two-step deformation process was carried out on Fe and FeCo amorphous alloys(Sm0.6Pr0.4)Co5+20wt.%at a plateau temperature of 630℃and a maximum temperature of 700℃-800℃.The grain size of magnets with Fe and FeCo added increases with increasing temperature,with a maximum of around 30nm.The Hci of both decreases with increasing temperature,with minimum values of 6.8kOe and 7.5kOe,respectively.The(BH)max of both increased first and then decreased,with the maximum values occurring at 750℃,22.8 MGoe and 22.5 MGoe,respectively.The addition of FeCo in the precursor exhibits higher squareness and Br‖/Br⊥ compared to the addition of Fe.At the highest deformation temperature of 750℃,when FeCo is added,the I(002)/I(111)of(Sm,Pr)Co7 is 90%.At this time,Br‖/Br⊥ is 3.41,while when pure Fe is added,(Sm,Pr)Co7 I(002)/I(111)is 71%,and Br‖/Br⊥ is 1.45. |
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