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Method for producing rare earth sintered magnet

A technology of sintered magnets and manufacturing methods, applied in the direction of inductance/transformer/magnet manufacturing, magnetic objects, magnetic materials, etc., can solve problems such as reduction, and achieve the effect of improving Hcj

Active Publication Date: 2018-02-16
HITACHI METALS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the R-T-B system sintered magnet, when the heavy rare earth element RH is used as R to replace the light rare earth element RL (Nd, Pr), H cj increase, but on the other hand, there is a residual flux density B r (hereinafter referred to as "B r ’) reduce the problem

Method used

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  • Method for producing rare earth sintered magnet
  • Method for producing rare earth sintered magnet
  • Method for producing rare earth sintered magnet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0087] · Determination of the amount of C

[0088] Under the conditions shown in Table 1 below, the mixed powder, binder, coupling agent, and solvent were mixed to prepare a paste. These compounding ratios are shown in Table 1 by Mass % (mass %).

[0089] The mixed powder in this example is made by mixing RLM alloy powder and RH fluoride powder at a mass ratio of 60:40. RLM alloy powder is made of Nd with a particle size of 150 μm or less produced by the centrifugal atomization method 70 Cu 30 alloy particles. RH fluoride powder is made of TbF with particle size below 100μm 3 Particle composition.

[0090] The binder used in this embodiment, as shown in Table 1, is EC (ethyl cellulose) or PVA (polyvinyl alcohol). Furthermore, the coupling agent is ethylene oxide-based SC (silane coupling agent), amine-based SC, amine-based TC (titanate-based coupling agent), vinyl-based SC, alkyl-based SC, or methacrylate-based SC. The solvent is ethanol when the binder is ethyl cellulo...

Embodiment 2

[0112] The same evaluation as in Example 1 was performed using the mixed powder, binder, and coupling agent shown in Samples A to F of Table 5 below. The prepared paste was coated on a PET film, and dried at 90° C. for 1 hour. Table 6 shows the ratio of each component in the dry film obtained through calculation.

[0113] [table 5]

[0114]

[0115] [Table 6]

[0116]

[0117] Table 7 and Table 8 corresponding to Table 3 and Table 4 obtained in Example 1 are shown below.

[0118] [Table 7]

[0119]

[0120] [Table 8]

[0121]

[0122] As can be seen from Table 7 and Table 8, when using a different type of mixed powder from Example 1, the difference in the amount of residual C in Table 7 was applied and heat-treated in the sample in which the difference in the amount of residual C was within the range of the present invention. Tight adhesion of coated film, H cj also increased substantially. However, in the samples in which the difference in the amount of res...

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Abstract

A coating film 200 of a paste that contains a resin binder 20 and a mixed powder obtained by mixing a metal powder 22 and a metal compound powder 24 is formed on the surface of an R-T-B system sintered magnet 100. After that, the metal component in the coating film 200 is dispersed into the sintered magnet 100 by performing a heat treatment. The coating film 200 contains carbon that remains afterthe heat treatment, and the carbon content in the coating film 200 before the heat treatment is adjusted so that the value obtained by subtracting the carbon content in the mixed powder in the paste before the heat treatment from the carbon content remaining after the heat treatment is within the range from 0.07% by mass to 0.50% by mass (inclusive) of the whole coating film 200 after the heat treatment.

Description

technical field [0001] The present disclosure relates to a method of manufacturing a rare earth sintered magnet. Background technique [0002] with R 2 T 14 R-T-B sintered magnets with B-type compounds as the main phase are known as the highest performance magnets among permanent magnets, and are used in various motors such as voice coil motors (VCM) for hard disk drives and motors for hybrid vehicles and home appliances. waiting. [0003] Due to the inherent coercivity H of the R-T-B sintered magnet at high temperature cj (hereinafter referred to as "H cj ”) is reduced, so it will cause irreversible thermal demagnetization. In order to avoid irreversible thermal demagnetization, it is required to maintain high H even at high temperatures when used in motors and other applications. cj . [0004] When replacing R with heavy rare earth elements RH (Dy, Tb) 2 T 14 When part of R in the B-type compound phase, the H of the R-T-B sintered magnet cj Raise, it's known. In ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02B22F3/24C22C28/00C23C10/52H01F1/057H01F1/08C22C38/00
CPCB22F3/24C22C28/00C22C38/00C23C10/52H01F1/057H01F1/08H01F41/02
Inventor 三野修嗣
Owner HITACHI METALS LTD