In this study, micromagnetism simulation by using timte dltterence method is cameo out on the Ncl21-el415/a-Fe nanocomposite magnet with soft phase imbedded in hard phase. The effects of soft magnetic phase size （S）...In this study, micromagnetism simulation by using timte dltterence method is cameo out on the Ncl21-el415/a-Fe nanocomposite magnet with soft phase imbedded in hard phase. The effects of soft magnetic phase size （S） on the magnetic properties and magnetic reversal modes are systematically analyzed. As S increases from 1 nm to 48 nm, the remanence （Jr） increases, while the coercivity （Hci） decreases, leading to the result that the magnetic energy prod- uct [（BH）max] first increases slowly, and then decreases rapidly, peaking at S = 24 nm with the （BH）max of 72.9 MGOe （1 MGOe = 7.95775 kJ.m-3）. Besides, with the increase of S, the coercivity mechanism of the nanocomposite magnet changes from nucleation to pinning. Furthermore, by observing the magnetic moment evolution in demagnetization pro- cess, the magnetic reversal of the soft phase in the nanocomposite magnet can be divided into three modes with the increase of S： coherent rotation （S 〈 3 nm）, quasi-coherent rotation （3 nm≤S 〈 36 nm）, and the vortex-like rotation （S ≥36 nm）.展开更多
The effects of Nb on the microstructure and magnetic properties of （Nd0.9Dy0.1）9.5Fe79_xCo5NbxB6.5 （x = 0, 1） nanocomposite magnets were investigated. A fine and uniform microstructure was achieved for the ribbons...The effects of Nb on the microstructure and magnetic properties of （Nd0.9Dy0.1）9.5Fe79_xCo5NbxB6.5 （x = 0, 1） nanocomposite magnets were investigated. A fine and uniform microstructure was achieved for the ribbons annealed at 710℃ for 4 min, enhancing the interaction coupling between grains and improving the magnetic properties. The results of three-dimensional atom probe （3DAP） indicated that Fe-Nb-B inter- granular phase existed at the grain boundaries, suppressing the grain growth during the crystallization process. The coercivity was improved from 224 to 643 kA/m for the modification of the microstructure.展开更多
Crystallization and magnetic properties of Nd2Fe14B/α-Fe nanocomposite magnets have been investigated by annealing the as-spun ribbons with magnetic field.The crystallization process was accelerated by field annealin...Crystallization and magnetic properties of Nd2Fe14B/α-Fe nanocomposite magnets have been investigated by annealing the as-spun ribbons with magnetic field.The crystallization process was accelerated by field annealing.The hysteresis loop became to be fat by magnetic annealing at 645 oC for 4 min,which was 690 oC for ribbons annealing without magnetic field.The relative content of α-Fe phase was increased from the results of XRD.The strength of the magnetic field had no obvious influence on the remanence and coercivity,but modified the squareness of hysteresis loop.展开更多
基金Project supported by the Key Program of the National Natural Science Foundation of China(Grant No.51331003)the International S&T Cooperation Program of China(Grant No.2015DFG52020)+1 种基金the General Program of Science and Technology Development Project of Beijing Municipal Education Commission,China(Grant No.KM201710005006)the State Key Laboratory of Advanced Metals and Materials,China(Grant No.2015-ZD02)
文摘In this study, micromagnetism simulation by using timte dltterence method is cameo out on the Ncl21-el415/a-Fe nanocomposite magnet with soft phase imbedded in hard phase. The effects of soft magnetic phase size （S） on the magnetic properties and magnetic reversal modes are systematically analyzed. As S increases from 1 nm to 48 nm, the remanence （Jr） increases, while the coercivity （Hci） decreases, leading to the result that the magnetic energy prod- uct [（BH）max] first increases slowly, and then decreases rapidly, peaking at S = 24 nm with the （BH）max of 72.9 MGOe （1 MGOe = 7.95775 kJ.m-3）. Besides, with the increase of S, the coercivity mechanism of the nanocomposite magnet changes from nucleation to pinning. Furthermore, by observing the magnetic moment evolution in demagnetization pro- cess, the magnetic reversal of the soft phase in the nanocomposite magnet can be divided into three modes with the increase of S： coherent rotation （S 〈 3 nm）, quasi-coherent rotation （3 nm≤S 〈 36 nm）, and the vortex-like rotation （S ≥36 nm）.
文摘The effects of Nb on the microstructure and magnetic properties of （Nd0.9Dy0.1）9.5Fe79_xCo5NbxB6.5 （x = 0, 1） nanocomposite magnets were investigated. A fine and uniform microstructure was achieved for the ribbons annealed at 710℃ for 4 min, enhancing the interaction coupling between grains and improving the magnetic properties. The results of three-dimensional atom probe （3DAP） indicated that Fe-Nb-B inter- granular phase existed at the grain boundaries, suppressing the grain growth during the crystallization process. The coercivity was improved from 224 to 643 kA/m for the modification of the microstructure.
基金Project supported by the State Key Lab of Advanced Metals Materials and Shanghai Education Commission of P.R. China (J51504)
文摘Crystallization and magnetic properties of Nd2Fe14B/α-Fe nanocomposite magnets have been investigated by annealing the as-spun ribbons with magnetic field.The crystallization process was accelerated by field annealing.The hysteresis loop became to be fat by magnetic annealing at 645 oC for 4 min,which was 690 oC for ribbons annealing without magnetic field.The relative content of α-Fe phase was increased from the results of XRD.The strength of the magnetic field had no obvious influence on the remanence and coercivity,but modified the squareness of hysteresis loop.
