Aichi Steel Corporation

Masao Yamazaki

Yoshinobu Honkura

Chisato Mishima

Anisotropic rare earth magnet powder particles include RTMB-type crystals of a tetragonal compound consisting of one or more rare earth element, B, and one or more transition element, and enveloping layers containing at least Nd and Cu. Surfaces of the RTMB-type crystals are enveloped by the enveloping layers. The particles has an average crystal grain diameter of 0.05 to 1 &#x3bc;m. The particles contain, when the whole particles are taken as 100 atomic %, 11.5 to 15 atomic % of total rare earth element (Rt); 5.5 to 8 atomic % of B; and about 0.05 atomic % to about 2 atomic % of Cu. The powder particles have an atomic ratio of Cu, which is a ratio of the total number of Cu atoms to a total number of atoms of Rt, falling within the range of 1 to 6%. The powder particles do not include dysprosium Dy, Tb, Ho and Ga. Coercivity of the magnetic powder is more than 955 kA/m.

Anisotropic rare earth magnet powder, method for producing the same, and bonded magnet

The anisotropic rare earth magnet powder of the present invention includes powder particles having RTMB-type crystals of a tetragonal compound of a rare earth element (R), boron (B), and a transition element (TM) having an average crystal grain diameter of 0.05 to 1 &#x3bc;m, and enveloping layers containing at least a rare earth element (R') and copper (Cu) and enveloping surfaces of the crystals. Owing to the presence of the enveloping layers, coercivity of the anisotropic rare earth magnet powder can be remarkably enhanced without using a scarce element such as Ga and Dy.

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Aichi, Japan

Masao Yamazaki