Yantai Zhenghai Magnetic Material Co., Ltd.

Nantong Zhenghai Magnet Co., Ltd.

Yongjiang Yu

Xiuyan Sun

Lei Liu

Nan Zhao

Xiaodong Tian

Zhiqiang Li

Yulin Wang

Bin Zhou

Wen Li

A method for producing a sintered R-iron (Fe)-boron (B) magnet, the method including: (1) producing a sintered magnet R1-Fe&#x2014;B-M, where R1 is neodymium (Nd), praseodymium (Pr), terbium (Tb), dysprosium (Dy), gadolinium (Gd), holmium (Ho), or a combination thereof; M is titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), gallium (Ga), calcium (Ca), copper (Cu), Zinc (Zn), silicon (Si), aluminum (Al), magnesium (Mg), zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), tungsten (W), molybdenum (Mo), or a combination thereof; (2) removing oil, washing using an acid solution, activating, and washing using deionized water the sintered magnet, successively; (3) mixing a superfine terbium powder, an organic solvent, and an antioxidant to yield a homogeneous slurry, coating the homogeneous slurry on the surface of the sintered magnet; and (4) sintering and aging the sintered magnet.

Method for producing sintered R-iron-boron magnet

A method for preparing an R&#x2014;Fe&#x2014;B based sintered magnet, including: preparing a R&#x2014;Fe&#x2014;B-M sintered magnet having a thickness of between 1 and 10 mm; spraying a layer of Tb or Dy having a thickness of between 10 and 200 &#x3bc;m on each surface of the sintered magnet in a sealed box under an Ar atmosphere by hot spraying method; and transferring the sintered magnet coated with the layer of Tb or Dy to a vacuum sintering furnace, heating the sintered magnet at the temperature of between 750 and 1000&#xb0; C. in a vacuum condition or under the Ar atmosphere, and allowing heavy rare earth element Tb or Dy to enter an inner part of the sintered magnet via grain boundary diffusion.

Method for preparing R-Fe-B based sintered magnet

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Yantai, China

Yongjiang Yu