Heat-resistant Isotropic Bonded NdFeB Magnet and Its Preparation Technology

Patent metadata

Field	Value
Publication number	US-2018166191-A1
Application number	US-201615567957-A
Country	US
Kind code	A1
Filing date	Mar 8, 2016
Priority date	Oct 12, 2015
Publication date	Jun 14, 2018
Grant date	—

Abstract

This patent invents a heat-resistant isotropic bonded NdFeB magnet and its preparation technology, belonging to the field of magnetic materials. In present invention, isotropic NdFeB magnetic powders is used as magnetic material, sodium silicate is used as principal binder, and epoxy resin is used as auxiliary binder to prepare heat-resistant isotropic bonded NdFeB magnets. The prepared magnets have greatly increased heat resistance to stand an operating temperature of 200° C., and have advantages of penetration and corrosion resistance. The invented heat-resistant isotropic bonded NdFeB magnets feature good magnetic properties and high operating temperature. During the preparation process, it has the advantage of simple equipment, easy operation, low cost. The technology is easy to large scale production, and has high economic value and huge application prospect in the field of permanent magnetic materials.

First claim

1 . A kind of heat resistant isotropic bonded NdFeB magnet comprises the following materials: isotropic NdFeB powders and binder as the main materials with proper surfactant and lubricant. The mass ratios of the main materials are 90˜96% of isotropic NdFeB powders, 3˜6.5% of sodium silicate binder, 0.5˜3.3% of epoxy resin binder, 0.1˜0.3% of surfactant, and 0.1˜0.3 lubricant.

2 . A kind of heat resistant isotropic bonded NdFeB magnet according to claim 1 , wherein the sodium silicate binder is sodium silicate aqueous solution with modulus of 3.1˜3.4 and baume degree of 39˜41°.

3 . A kind of heat resistant isotropic bonded NdFeB magnet according to claim 1 , wherein the surfactants are preferred to KH-550, KH560, stearic acid, aluminate ester, and titanate ester.

4 . A kind of heat resistant isotropic bonded NdFeB magnet according to claim 1 , wherein the lubricants are preferred to paraffin, glycerol, silicate ester, and silicone oil.

5 . A method for preparing heat resistant isotropic bonded NdFeB magnet according to claim 1 , comprises the following steps:
(1) The bonded magnetic powders A is obtained by mixing isotropic NdFeB magnetic powder with a certain mass of surfactant and stirring homogeneously; (2) The bonded magnetic powders B is obtained by mixing bonded magnetic powders A prepared in step (1) with a certain mass of epoxy resin and stirring homogeneously until it becomes loose; (3) The bonded magnetic powders C is obtained by mixing bonded magnetic powders B prepared in step (2) with a certain mass of sodium silicate and stirring homogeneously until it becomes loose; (4) The bonded magnetic powders D is obtained by mixing bonded magnetic powders C prepared in step (3) with a certain mass of lubricant and stirring homogeneously; (5) The bonded magnetic powders E is obtained by spraying a small amount of organic solvent to bonded magnetic powders D prepared in step (4) to volatilize water of the binder and stirring homogeneously until it becomes loose; (6) The initial green compact F is obtained by pressing bonded magnetic powders E prepared in step (5) in moulding press machine; (7) The densely compact G is obtained by densifying initial green compact F prepared in step (6) in isostatic pressing machine; (8) The heat resistant isotropic bonded NdFeB magnets is obtained by curing densely compact G prepared in step (7), wherein the curing temperature is 175˜200° C. and curing time is 30˜40 min.

6 . The method according to claim 5 , wherein the above mentioned epoxy resin is diluted and dissolved by acetone before using. After dissolution, it is used immediately.

7 . The method according to claim 5 , wherein the above mentioned organic solvent is one of acetone, methyl alcohol, ethyl alcohol and ethyl acetate, or a mixture of them.

Assignees

• Univ Beijing Technology

Inventors

• Yue Ming
• Yin Yuxia
• Liu Weiqiang
• Hu Ruijin
• Zhang Dongtao
• Li Chenglin

Classifications

• B22F1/10

  Metallic powder containing lubricating or binding agents; Metallic powder containing organic material · CPC title

• H01F41/0266 Primary

  Moulding; Pressing (H01F41/0273 takes precedence; hard magnetic particles H01F1/06, H01F1/11) · CPC title

• B22F3/03

  Press-moulding apparatus therefor · CPC title

• B22F2301/45

  Rare earth metals, i.e. Sc, Y, Lanthanides (57-71) · CPC title

• H01F7/02

  Permanent magnets {[PM]} · CPC title