Statistical model of magnetization reversal was used to simulate the magnetization reversal behavior in the sintered Nd-Fe-B magnets with double grain-size distributions due to the abnormal grain growth (AGG). The magnetic properties and mechanical properties due to the formation of AGG grains in Nd-Fe-B sintered magnets were tested. The results show that the magnetic properties, especially the rectangularity were severely deteriorated after the formation of the AGG grains and a step was shown on the demagnetization curve, and the occurrence of AGG mayaccount for the poor rectangularity and existence of the step on demagnetization curve according to the statistical model of magnetization reversal. The fracture toughness and bending strength are lowered because of the stress concentration in the AGG grains. The SEM images show that the formation of AGG grains is caused by the solid sintering due to the absence of RE-rich phase. Statistical model of magnetization reversal can qualitative by explain the dependence of the magnetization reversal behavior on the grain size in the Nd-Fe-B sintered magnets.
参考文献
| [1] | Sagawa M;Fujimura S;Togawa N et al.New material for permanent magnets on a base of Nd and Fe[J].Journal of Applied Physics,1984,55:2083. |
| [2] | Croat J J;Herbst J F;Lee R W et al.Pr-Fe and Nd-Fe-based materials:A new class of high-performance permanent magnets[J].Journal of Applied Physics,1984,55:2078. |
| [3] | Horton J.A.;Wright J.L. .Fracture toughness of commercial magnets[J].IEEE Transactions on Magnetics,1996(5):4374-4376. |
| [4] | Pandian S.;Chandrasekaran V.;Markandeyulu G.;Iyer KJL.;Rao KVSR. .Effect of Al, Cu, Ga, and Nb additions on the magnetic properties and microstructural features of sintered NdFeB[J].Journal of Applied Physics,2002(10):6082-6086. |
| [5] | Jiang J H;Zeng Z P;Wu J S et al.Influence of alloying elements on mechanical properties and structure of sintered Nd-Fe-Co-B magnets[J].Journal of Magnetism and Magnetic Materials,2000,214:618. |
| [6] | Szymura S;Rabinovich Y M;Bala H et al.The correlation between the coercivity and the mechanical properties of sintered rare-earth-iron-boron magnets[J].Journal of Physics:Condensed Matter,1994,6:3573. |
| [7] | Liu S;Cao D.[A].August Newark,Delaware,2002:360. |
| [8] | Liu JF;Vora P;Walmer MH;Kottcamp E;Bauser SA;Higgins A;Liu S .Microstructure and magnetic properties of sintered NdFeB magnets with improved impact toughness - art. no. 10H101[J].Journal of Applied Physics,2005(10):H101-0. |
| [9] | Rodewald W;Katter M.[A].Annecy,France,2004:486. |
| [10] | Withey P.A.;Kennett H.M. .The magnetic and mechanical properties of NdFeB type permanent magnets and the effect of quenching[J].IEEE Transactions on Magnetics,1990(5):2619-2621. |
| [11] | Shi D K;Jin Z H.Mechanical Property of Material[M].西安:西安交通大学出版社,1997:74. |
| [12] | Ramesh R;Srikrishna K .Magnetization reversal in nucleation controlled magnets.1.Theory[J].Journal of Applied Physics,1988,11:64. |
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