公开(公告)号：US11742120B2

公开(公告)日：2023-08-29

申请号：US17520452

申请日：2021-11-05

Applicant: BEIJING UNIVERSITY OF TECHNOLOGY

Inventor： Weiqiang Liu ,  Hao Chen ,  Ming Yue ,  Zhi Li ,  Yantao Yin ,  Yuqing Li ,  Hongguo Zhang

IPC: H01F1/057 ,  H01F1/053 ,  H01F1/055 ,  H01F7/02 ,  H01F41/02 ,  B22F9/04 ,  B22F9/02

CPC classification number: H01F1/0573 ,  B22F9/023 ,  B22F9/04 ,  H01F1/0536 ,  H01F1/0551 ,  H01F1/0553 ,  H01F1/0557 ,  H01F1/0577 ,  H01F7/021 ,  H01F41/0266 ,  H01F41/0273 ,  H01F41/0293

Abstract: A two-step diffusion method for preparing high-performance dual-main-phase sintered mischmetal-iron-boron magnet belongs to the preparing technical field of rare earth permanent magnet materials. The compositions of the two main phase alloys are RE-Fe—B (RE is Nd or Pr) and (Nd, MM)-Fe—B (MM is mischmetal), respectively. First, PrHoFe strip-casting alloy is used as a diffusion source. Next, a PrHo-rich layer is uniformly coated on the surface of (Nd, MM)-Fe—B hydrogen decrepitation powders. The higher anisotropic fields of Pr2Fe14B and Ho2Fe14B are used to improve the coercivity. Then, the ZrCu strip-casting alloy is used as a diffusion source. A Zr-rich layer is uniformly coated on the surface of the powders after the first-step diffusion, which prevents the growth of the MM-rich main phase grains during the sintering process and the inter-diffusion between the two main phases, thus obtaining high coercivity.

公开(公告)号：US10210972B2

公开(公告)日：2019-02-19

申请号：US15567957

申请日：2016-03-08

Applicant: BEIJING UNIVERSITY OF TECHNOLOGY

Inventor： Ming Yue ,  Yuxia Yin ,  Weiqiang Liu ,  Ruijin Hu ,  Dongtao Zhang ,  Chenglin Li

IPC: B22F1/00 ,  B22F3/03 ,  H01F7/02 ,  H01F1/057 ,  H01F41/02 ,  C22C33/02 ,  C22C38/00

Abstract: This patent invents a heat-resistant isotropic bonded NdFeB magnet and its preparation technology, belonging to the field of magnetic materials. In present invention, isotropic NdFeB magnetic powders is used as magnetic material, sodium silicate is used as principal binder, and epoxy resin is used as auxiliary binder to prepare heat-resistant isotropic bonded NdFeB magnets. The prepared magnets have greatly increased heat resistance to stand an operating temperature of 200° C., and have advantages of penetration and corrosion resistance. The invented heat-resistant isotropic bonded NdFeB magnets feature good magnetic properties and high operating temperature. During the preparation process, it has the advantage of simple equipment, easy operation, low cost. The technology is easy to large scale production, and has high economic value and huge application prospect in the field of permanent magnetic materials.

公开(公告)号：US20220059262A1

公开(公告)日：2022-02-24

申请号：US17520452

申请日：2021-11-05

Applicant: BEIJING UNIVERSITY OF TECHNOLOGY

Inventor： Weiqiang Liu ,  Hao Chen ,  Ming Yue ,  Zhi Li ,  Yantao Yin ,  Yuqing Li ,  Hongguo Zhang

IPC: H01F1/055 ,  H01F7/02 ,  H01F1/053

Abstract: A two-step diffusion method for preparing high-performance dual-main-phase sintered mischmetal-iron-boron magnet belongs to the preparing technical field of rare earth permanent magnet materials. The compositions of the two main phase alloys are RE-Fe—B (RE is Nd or Pr) and (Nd, MM)-Fe—B (MM is mischmetal), respectively. First, PrHoFe strip-casting alloy is used as a diffusion source. Next, a PrHo-rich layer is uniformly coated on the surface of (Nd, MM)-Fe—B hydrogen decrepitation powders. The higher anisotropic fields of Pr2Fe14B and Ho2Fe14B are used to improve the coercivity. Then, the ZrCu strip-casting alloy is used as a diffusion source. A Zr-rich layer is uniformly coated on the surface of the powders after the first-step diffusion, which prevents the growth of the MM-rich main phase grains during the sintering process and the inter-diffusion between the two main phases, thus obtains high coercivity.

公开(公告)号：US09728310B2

公开(公告)日：2017-08-08

申请号：US15133042

申请日：2016-04-19

Applicant: BEIJING UNIVERSITY OF TECHNOLOGY ,  ANHUI EARTH-PANDA ADVANCE MAGNETIC MATERIAL CO., LTD.

Inventor： Ming Yue ,  Weiqiang Liu ,  Xiantao Li ,  Meng Li ,  Min Liu ,  Dongtao Zhang ,  Xiaowen Yin ,  Xiulian Huang ,  Jingwu Chen ,  Xiaofei Yi

IPC: H01F1/053 ,  C22C38/60 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/10 ,  C22C38/06 ,  C22C38/00 ,  C22C33/02 ,  B22F1/00 ,  B22F3/087 ,  B22F3/10 ,  B22F3/16 ,  B22F5/00 ,  B22F9/04 ,  B22F9/30 ,  C21B15/00 ,  H01F41/02

CPC classification number: H01F1/0536 ,  B22F1/0003 ,  B22F3/087 ,  B22F3/10 ,  B22F3/16 ,  B22F5/00 ,  B22F9/04 ,  B22F9/30 ,  B22F2301/355 ,  B22F2303/01 ,  B22F2303/15 ,  B22F2303/45 ,  B22F2304/10 ,  B22F2998/10 ,  C21B15/00 ,  C22C33/0235 ,  C22C33/0264 ,  C22C33/0278 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/06 ,  C22C38/10 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/60 ,  H01F1/0577 ,  H01F41/0266 ,  H01F41/0273 ,  B22F9/20 ,  B22F3/1017

Abstract: The present invention discloses a short process preparation technology of sintered NdFeB magnets from the NdFeB sludge, which relates to a field of recycle technology of NdFeB sludge. The present invention comprises the following steps: water bath distillation of organics in sludge, ultrasonic cleaning, calcium reduction and diffusion, ultrasonic rinsing in a magnetic field and drying, powders mixing and sintering. NdFeB sludge as raw materials was directly prepared from recycled sintered magnets with high magnetic properties. Most of the organics in the sludge could be removed by a vacuum distillation process with stepwise heating. The ultrasonic rinsing process in a magnetic field could effectively remove the remaining organics. The recycled sintered magnets exhibited good maximum energy product [(BH)max] of 35.26 MGOe. The present invention has important features, such as the short processing time, efficient environmental protection, high recycling rate and effective utilization rate of rare earth metals.