R-T-B based permanent magnet

A R-T-B, permanent magnet technology, applied in the direction of magnetic objects, magnetic materials, inorganic materials, etc., can solve the problems of controllability, difficult control of magnetic force, reduced efficiency of variable flux motors, etc., and achieve low coercivity. , The effect of high residual magnetic flux density and high controllability

Active Publication Date: 2015-09-30
TDK CORPARATION
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in Patent Document 3, if Ce is required as the rare earth element R in order to control the coercive force to a low value preferable as a variable magnet, and the residual magnetic flux density Br is about 8 kG to 12.5 kG, it will not reach The residual magnetic flux density Br of the Nd-Fe-B permanent magnet used as a fixed magnet is about 13kG
[0014] In addition, when used as a variable magnet, its controllability becomes a problem
When changing the magnetic force by applying a magnetic field from the outside, if the magnetic force changes steeply with respect to the magnetic field, it becomes difficult to control the magnetic force
If the magnetic force of the variable magnet cannot be controlled arbitrarily, the efficiency of the variable flux motor is significantly reduced

Method used

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  • R-T-B based permanent magnet
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Examples

Experimental program
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Effect test

Embodiment 1～8、 comparative example 1～2

[0052] With 14.2 mol% R-5.8 mol% B-balance Fe as a basic component, 0.5 mass % Co, 0.18 mass % Al, and 0.1 mass % Cu were added thereto. A sintered body of this composition was produced. The composition (atomic %) and firing time of R are shown in Table 1. Their magnetic properties, residual magnetism deviation and demagnetization were measured. The results are shown in Table 1.

[0053] The absolute value of the coercive force HcJ decreases by adding Y, Ce, and La compared to 100% Nd. In addition, a low ΔJ / Δ(H / HcJ) was shown. As a result, the variation in residual magnetization is small, and the controllability of magnetization is good. Since the squareness ratio (HK / HcJ) was high, no demagnetization was found either. In Comparative Examples 1 and 2, the coercivity HcJ was high, and the variation in remanence was large. Example 6 showed low ΔJ / Δ(H / HcJ), and the residual magnetism deviation became small. However, if the coercive force HcJ is significantly lowered to 1.2...

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Abstract

The present invention provides a R-T-B based permanent magnet, comprising a demagnetization curve having a slope ΔJ/Δ(H/HcJ) of less than 400 kG at a region where the value of magnetic field is Hk or less, wherein it is preferable that R in the composition of R-T-B is represented by (R11-xR2x), and T represents one or more transition metal elements containing Fe or a combination of Fe and Co as necessary, where: R1 represents the rare earth element(s) composed of one or more elements selected from the group consisting of Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and R2 contains at least one element selected from the group consisting of Y, Ce and La, and 0.2≰x≰0.7.

Description

technical field [0001] The invention relates to an R-T-B permanent magnet. Background technique [0002] known as tetragonal R 2 T 14 The R-T-B permanent magnet (R is a rare earth element, T is Fe or a part of which is replaced by Co, B is boron) with B compound as the main phase has excellent magnetic properties, and since the invention in 1982 (Patent Document 1: Japan Japanese Patent Laid-Open No. 59-46008) is a representative high-performance permanent magnet. [0003] An R-T-B magnet composed of Nd, Pr, Dy, Ho, and Tb as a rare earth element R has a large anisotropic magnetic field Ha, and is preferable as a permanent magnet material. Among them, Nd-Fe-B magnets in which the rare earth element R is Nd have a good balance of saturation magnetization Is, Curie temperature Tc, and anisotropic magnetic field Ha, and are better than those using other rare earth elements in terms of resource amount and corrosion resistance. R's R-T-B magnets are more excellent, so they ar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F1/08H02K1/02
CPCH01F1/01H02K1/02H01F1/0577
Inventor 榎户靖铃木健一
Owner TDK CORPARATION
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