Since the 1980 s, Nd–Fe–B with largest energy product(BH)max approaching the theoretical limit has become the landmark of permanent magnetic material.The application spectrum for Nd–Fe–B continues to expand over t...Since the 1980 s, Nd–Fe–B with largest energy product(BH)max approaching the theoretical limit has become the landmark of permanent magnetic material.The application spectrum for Nd–Fe–B continues to expand over time both in the industrial and commercial sectors, which leads to growing research interests for solving the long-standing drawbacks of Nd–Fe–B, i.e., poor corrosion resistance, low coercivity, high Dy/Tb and low La/Ce/Y consumption.Concerning the above obstacles, we aim to present the novel grain boundary restructuring(GBR) approach, from GB design, processing, to structure evolution and property evaluation with a focus on the corrosion and coercivity mechanism of the restructured 2:14:1-typed magnets.Starting with an introduction to the fundamental of GBR, two representative examples,high-electrode-potential(Pr, Nd)32.5Fe62.0Cu5.5 and low-melting-point Dy71.5Fe28.5, are given with detailed descriptions of the advantages of GBR to enhance the intrinsic anti-corrosion stability and to strengthen the coercivity at low Dy consumption.Microstructure–property correlations are established to understand the critical importance of regulating the restructured GB phase to maximize the all-round performance of the 2:14:1-typed permanent magnets.Aiming at sustainable and balanced development of rare earth(RE) industry, the proceeding section proposes new prototypes of La–Ce and Y–Ce co-substitutions with dual benefits of stabilizing the 2:14:1 tetragonal phase and strengthening the intrinsic hard magnetism.The findings of additional REFe2 intergranular phase delight that the GBR approach also opens up a new horizon of research and application to develop high-performance La/Ce/Y-rich permanent magnets with deliberately tailored GB phase.展开更多
The obstacles of inferior microstructure and poor magnetic properties of(La,Ce)-Fe-B type magnets stand in the way of expanding their applications.In this work,(La,Ce)-Fe-B melt-spun ribbons were prepared with differe...The obstacles of inferior microstructure and poor magnetic properties of(La,Ce)-Fe-B type magnets stand in the way of expanding their applications.In this work,(La,Ce)-Fe-B melt-spun ribbons were prepared with different La/Ce ratios and rare earth contents.The microstructure and magnetic properties of these ribbons were investigated.With the La/Ce ratio increased,the fraction of the CeFe_(2)phase decreased and the β-La phase segregated among matrix grains,which deteriorated the coercivity of the ribbons.Reducing the rare earth content effectively suppressed the β-La phase and improved the proportion of the matrix phase in the ribbons.Here,the optimal alloy composite(La_(15)Ce_(85))_(14)Fe_(80)B_(6) has been obtained with modified microstructure and inhibited secondary phases.Good ribbon performance was tested,with H_(cj)=4.51 kOe,B_(r)=6.29 kG and(BH)_(max)=6.81 MGOe.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51801181,51571176,51590881,and 51622104)the National Key Research and Development Program of China(Grant No.2016YFB0700902)+1 种基金the Key Research and Development Program of Zhejiang Province,China(Grant No.2017C01031)the Fundamental Research Funds for the Central Universities,China(Grant No.2019QNA4011)
文摘Since the 1980 s, Nd–Fe–B with largest energy product(BH)max approaching the theoretical limit has become the landmark of permanent magnetic material.The application spectrum for Nd–Fe–B continues to expand over time both in the industrial and commercial sectors, which leads to growing research interests for solving the long-standing drawbacks of Nd–Fe–B, i.e., poor corrosion resistance, low coercivity, high Dy/Tb and low La/Ce/Y consumption.Concerning the above obstacles, we aim to present the novel grain boundary restructuring(GBR) approach, from GB design, processing, to structure evolution and property evaluation with a focus on the corrosion and coercivity mechanism of the restructured 2:14:1-typed magnets.Starting with an introduction to the fundamental of GBR, two representative examples,high-electrode-potential(Pr, Nd)32.5Fe62.0Cu5.5 and low-melting-point Dy71.5Fe28.5, are given with detailed descriptions of the advantages of GBR to enhance the intrinsic anti-corrosion stability and to strengthen the coercivity at low Dy consumption.Microstructure–property correlations are established to understand the critical importance of regulating the restructured GB phase to maximize the all-round performance of the 2:14:1-typed permanent magnets.Aiming at sustainable and balanced development of rare earth(RE) industry, the proceeding section proposes new prototypes of La–Ce and Y–Ce co-substitutions with dual benefits of stabilizing the 2:14:1 tetragonal phase and strengthening the intrinsic hard magnetism.The findings of additional REFe2 intergranular phase delight that the GBR approach also opens up a new horizon of research and application to develop high-performance La/Ce/Y-rich permanent magnets with deliberately tailored GB phase.
基金Project supported by the fifth batch of major scientific and technological research projects in the Panxi Experimental Zone of Sichuan Province,the new functional materials and applications of rare earth vanadium titanium(Grant No.2020SCUNG201).
文摘The obstacles of inferior microstructure and poor magnetic properties of(La,Ce)-Fe-B type magnets stand in the way of expanding their applications.In this work,(La,Ce)-Fe-B melt-spun ribbons were prepared with different La/Ce ratios and rare earth contents.The microstructure and magnetic properties of these ribbons were investigated.With the La/Ce ratio increased,the fraction of the CeFe_(2)phase decreased and the β-La phase segregated among matrix grains,which deteriorated the coercivity of the ribbons.Reducing the rare earth content effectively suppressed the β-La phase and improved the proportion of the matrix phase in the ribbons.Here,the optimal alloy composite(La_(15)Ce_(85))_(14)Fe_(80)B_(6) has been obtained with modified microstructure and inhibited secondary phases.Good ribbon performance was tested,with H_(cj)=4.51 kOe,B_(r)=6.29 kG and(BH)_(max)=6.81 MGOe.
