公开(公告)号：US20150179319A1

公开(公告)日：2015-06-25

申请号：US14579315

申请日：2014-12-22

Applicant: TDK CORPORATION

Inventor： Yoshinori FUJIKAWA ,  Yuki NAGAMINE ,  Wakako OKAWA ,  Chikara ISHIZAKA ,  Eiji KATO ,  Katsuo SATO

IPC: H01F1/057

CPC classification number: H01F1/057 ,  H01F1/0577

Abstract: The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises R2T14B crystal grains as the main phases and the crystal boundary phases among R2T14B crystal grains. The microstructure of the sintered body is controlled by at least containing the first crystal boundary phases and the second crystal boundary phases, wherein the first crystal boundary phases contain at least R-T-M in the ranges of 20 to 40 atomic % for R, 60 to 75 atomic % for T and 1 to 10 atomic % for M, and the second crystal boundary phases contains at least R-T-M in the ranges of 50 to 70 atomic % for R, 10 to 30 atomic % for T and 1 to 20 atomic % for M.

Abstract translation: 本发明提供了一种稀土类磁体，其中即使Dy和Tb等重稀土元素的量与过去相比明显减少，也可以抑制高温下的退磁率，或者不存在这种重稀土 使用地球元素。 本发明的稀土类磁体是以R2T14B晶粒为主相和R2T14B晶粒之间的晶界相的烧结磁体。 烧结体的显微结构至少含有第一晶界相和第二晶界边界相，其中第一晶界相至少含有R为20〜40原子％的RTM，60〜75原子 对于T为1％，对于M为1至10原子％，并且第二晶界相至少包含在R为50至70原子％，T为10至30原子％和对于M为1至20原子％的范围内的RTM。

公开(公告)号：US20150179318A1

公开(公告)日：2015-06-25

申请号：US14578713

申请日：2014-12-22

Applicant: TDK CORPORATION

Inventor： Yoshinori FUJIKAWA ,  Yuki NAGAMINE ,  Wakako OKAWA ,  Chikara ISHIZAKA ,  Eiji KATO ,  Katsuo SATO

IPC: H01F1/057 ,  C22C38/00 ,  C22C38/02 ,  C22C38/16 ,  C22C38/06

CPC classification number: H01F1/057 ,  C22C33/0278 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/06 ,  C22C38/16 ,  C22C2202/02 ,  H01F1/0577

Abstract: The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises R2T14B crystal grains as the major phases and the crystal boundary phases among the R2T14B crystal grains. The microstructure of the sintered body is controlled by including crystal boundary phases containing at least R, T and M in the crystal boundary phases, wherein the relative atomic ratios of R, T and M are as follows, i.e., 60 to 80% for R, 15 to 35% for T and 1 to 20% for M.

Abstract translation: 本发明提供了一种稀土类磁体，其中即使Dy和Tb等重稀土元素的量与过去相比明显减少，也可以抑制高温下的退磁率，或者不存在这种重稀土 使用地球元素。 本发明的稀土类磁体是包含R2T14B晶粒作为主相和R 2T14B晶粒中的晶界相的烧结磁体。 通过在晶界边界相中包含至少含有R，T和M的晶界相来控制烧结体的组织，其中R，T和M的相对原子比如下，即R为60〜80％ ，T为15〜35％，M为1〜20％

公开(公告)号：US20140292453A1

公开(公告)日：2014-10-02

申请号：US14229253

申请日：2014-03-28

Applicant: TDK CORPORATION

Inventor： Eiji KATO ,  Yoshinori FUJIKAWA ,  Taeko TSUBOKURA ,  Chikara ISHIZAKA ,  Katsuo SATO

IPC: H01F1/057

Abstract: The present invention provides a rare earth based magnet that inhibits the high temperature demagnetization rate even when less or no heavy rare earth elements such as Dy, Tb and the like are used. The rare earth based magnet according to the present invention includes R2T14B main phase crystal grains and grain boundary phases between adjacent main phase crystal grains. In any cross-section of the rare earth based magnet, when evaluating the circular degree of the main phase crystal grains with Wadell's Roundenss A, the shape of the main phase crystal grains is controlled such that the Roundness A becomes 0.24 or more.

Abstract translation: 本发明提供一种稀土类磁体，即使在使用Dy或Tb等稀土元素较少的情况下也能够抑制高温退磁率。 根据本发明的稀土类磁体包括相邻的主相晶粒之间的R2T14B主相晶粒和晶界相。 在稀土类磁体的任何截面中，当用Wadell's Roundens A评估主相晶粒的圆度时，控制主相晶粒的形状，使得圆度A变为0.24以上。