Micromagnetic Simulation of Magnetization Reversal in SmCo5／Sm2Co17 Magnets

A three-dimensional finite element micromagnetic algorithm was developed to study the magnetization reversal of the SmCo5/Sm2Co17 based magnets. The influences of the microstructure and magnetic parameters on the coercivity were studied based on the model consisting of 64 irregular cells according to the experimental microstructure. Numerical results show that the coercivity increases with increasing the 2: 17-type cell size. Large cell boundary thickness leads to small coercivity. The drop of anisotropy constant of 1:5 phase leads to the coercivity reducing, while the effect of exchange constant of 1 : 5 phase on coercivity is contrary to that of exchange constant. The calculated field dependence of coercivity can be predicted by an inhomogeneous domain - wall pinning model. The microstructure parameter was analyzed by comparing the calculated coercivity.     

具有宽过冷液相区的Fe73NbxAl5—xGe2P10C6B4非晶态合金的热稳定性和磁性

本文选择了成发为Fe73NbxAl5-xGe2P10C6B4（x＝0,1,5,原子百分比）的合金系。利用单辊急冷法制备出宽约5mm、厚度不同的条带,通过DSC、XRD以及Faraday磁天平、静态磁性测量仪等手段研究了合金的热稳定性、非晶结构和磁性能。发现含1％（原子）Nb的Fe73NbxAl5-xGe2P10C6B4合金的过冷液相区△Tx最宽,达到66K,且能制备出厚度大小100μm的完全非晶。整个合金都具有很高的饱和强化强度σs。经973K退火900s后,由于α－Fe等晶相的析出,使得各金的σs和Hc都迅速升高。     

具有宽过冷液相区的Fe63Co7NbxZr10-xB20非晶态合金的热稳定性和磁性研究

利用单辊急冷法制备出厚约35μm宽5mm的 Fe63Co7NbxZr10-xB20条带,并研究了合金的热稳定性、非晶结构和磁性能.结果表明,含4at%Nb的Fe63Co7Nb4Zr6B20合金过冷液相区Δ Tx最宽,达到79K.合金系的饱和比磁化强度σs随着Nb含量的增加而线性减小.合金系经973K退火900s,由于α\|Fe等相的析出,使得合金的σs和Hc均迅速升高.     

Micromagnetic Analysis on Demagnetization Process of Single-Phase Nanocrystalline Permanent Magnets with Different Degrees of Orientation

A three-dimentional finite element micromagnetic algorithm was developed to study the magnetization reversal of Pr2Fe14B single-phase nanocrystalline permanent magnets. A single-phase nanocrystalline Pr2Fe14B magnets composed of 216 irregular shaped grains was built. The magnetic hysteresis loops were simulated by micromagnetic finite element method. The contribution of intergrain exchange coupling ment degree （IGEC） to remanence enhancement is considered related to the alignin oriented magnets, and decreased with improved grain alignment. For the magnets with perfectly crystallo- graphic alignment of grains, the contribution of IGEC to remanence enhancement is nearly zero. The shape of demagnetization curve is not only dependent on grain alignment degree but also on the strength of IGEC in magnets.     

具有宽过冷液相区的Fe_(73)Nb_xAl_(5-x)Ge_2P_(10)C_6B_4非晶态合金的热稳定性和磁性

本文选择了成分为Fe73NbxAl5-xGe2 P10 C6B4 (x =0 ,1,3,5 ,原子百分比 )的合金系。利用单辊急冷法制备出宽约 5mm、厚度不同的条带 ,通过DSC、XRD以及Faraday磁天平、静态磁性测量仪等手段研究了合金的热稳定性、非晶结构和磁性能。发现含 1% (原子 )Nb的Fe73NbxAl5-xGe2 P10 C6B4 合金的过冷液相区ΔTx 最宽 ,达到 6 6K ,且能制备出厚度大于 10 0 μm的完全非晶。整个合金系都具有很高的饱和比磁化强度 σs 。经 973K退火 90 0s后 ,由于α Fe等晶相的析出 ,使得各合金的σs 和Hc 都迅速升高     

具有宽过冷液相区的Fe63Co7NbxZr10—xB20非晶态合金的热稳定性和磁性研究

利用单辊急冷法制备出厚约35μm宽5mm的Fe63Co7NbxZr10-xB20条带，并研究了合金的热稳定性、非晶结构和磁性能。结果表明，含4at%Nb的Fe63Co7Nb4Zr6B20合金过冷液相区ΔTx最宽，达到79K。合金系的饱和比磁化强度σs随着Nb含量的增加而线性减小。合金系经973K退火900s，由于α-Fe等相的析出，使得合金的σs和Hc均迅速升高。     

Investigation on Hard Magnetic Properties of Nanocomposite Permanent Magnets with Precipitate-Typed Microstructure by Micromagnetic Finite-Element Methods

Maximumenergyproduct (BH) maxisakeychar acteristicofapermanentmagnet (PM ) .Theoptimal(BH) maxislimitedbythevalueofJr2 / 4 μ0 (Jrrema nence)correspondingtoanidealrectangularhysteresisloopwhencoercivityμ0 HcisatleastlargerthanJr/ 2 .FormostrareearthPM ,thecoercivityisfarlargerthantheremanence[1,2 ] .Thus ,remanenceenhance mentbecomesanimportantroleindeveloping(BH) max.Sincehighremanencewasfoundinisotrop icnanostructuredPM ,muchefforthasbeenpaidtoachievehighperformancePM[3,4 ] .Thehigh…