Xiamen, China
Xiamen, China

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Patent
Xiamen Tungsten Co. | Date: 2017-02-08

The present invention discloses a W-containing R-Fe-B-Cu serial sintered magnet and quenching alloy. The sintered magnet contains an R_(2)Fe_(14)B-type main phase, the R being at least one rare earth element comprising Nd or Pr; the crystal grain boundary of the rare earth magnet contains a W-rich area above 0.004 at% and below 0.26 at%, and the W-rich area accounts for 5.0 vol%11.0 vol% of the sintered magnet. The sintered magnet uses a minor amount of W pinning crystal to segregate the migration of the pinned grain boundary in the crystal grain boundary to effectively prevent abnormal grain growth and obtain significant improvement. The crystal grain boundary of the quenching alloy contains a W-rich area above 0.004 at% and below 0.26 at%, and the W-rich area accounts for at least 50 vol% of the crystal grain boundary.


Patent
Xiamen Tungsten Co. | Date: 2016-10-05

The present invention discloses a low-B rare earth magnet. The rare earth magnet contains a main phase of R_(2)T_(14)B and comprises the following raw material components: 13.5 at%4.5 at% of R, 5.2 at%5.8 at% of B, 0.3 at%0.8 at% of Cu, 0.3 at%3 at% of Co, and the balance being T and inevitable impurities, the R being at least one rare earth element comprising Nd, and the T being an element mainly comprising Fe. 0.30.8 at% of Cu and an appropriate amount of Co are co-added into the rare earth magnet , so that three Cu-rich phasesormed in the grain boundary, and the magnetic effect of the three Cu-rich phases existing in the grain boundary and the solution of the problem of insufficient B in the grain boundary can obviously improve the squareness and heat-resistance of the magnet.


A manufacturing method of a powder for rare earth magnet and the rare earth magnet based on evaporation treatment, includes the steps of: coarsely crushing an alloy for the rare earth magnet and then finely crushing to obtain a fine powder; and evaporating the fine powder and an evaporation material in vacuum or in inert gas atmosphere; wherein the weight ratio of the evaporation material evaporated to the fine powder and the fine powder is 10-60.05:1. By adding the process of evaporation treatment of fine powder before the process of compacting under a magnetic field and after the process of fine crushing, the sintering property of the powder is changed drastically; a magnet with a high coercivity, a high squareness and a high heat resistance is obtained.


A manufacturing method of an alloy powder for rare earth magnet and the rare earth magnet based on heat treatment includes the following: an alloy of the rare earth magnet is firstly coarsely crushed and then finely crushed by jet milling to obtain a fine powder; the fine powder is obtained by being heated in vacuum or in inert gas atmosphere at a temperature of 100 C.1000 C. for 6 minutes to 24 hours. The heat treatment of fine powder is performed after the process of finely crushed jet milling before the process of compacting under a magnetic field, so that the sintering property of the powder is changed drastically, and it obtains a magnet with a high coercivity, a high squareness and a high heat resistance.


The present invention discloses manufacturing methods of a powder for compacting rare earth magnet powder and rare earth magnet that omit jet milling process, which comprises the steps as follows: 1) casting: casting the molten alloy of rare earth magnet raw material by strip casting method to obtain a quenched alloy with average thickness in a range of 0.20.4 mm; 2) hydrogen decrepitation: decrepitating the quenched alloy and a plurality of rigid balls into a rotating hydrogen decrepitation container simultaneously, the quenched alloy is crushed under a hydrogen pressure between 0.011 MPa, cooling the alloy and the balls, then screening the mixture to remove the rigid balls and obtain the powder. As the jet milling process is omitted, the oxygenation during the process of the jet milling may be avoided, therefore the process may be non-oxide, and the mass production of magnet with super high property may be possible.


The present invention discloses manufacturing methods of a powder for compacting rare earth magnet and rare earth magnet that omit jet milling process, which comprise the steps as follows: 1) casting: casting the molten alloy of rare earth magnet raw material by strip casting method to obtain a quenched alloy with average thickness in a range of 0.20.4 mm; 2) hydrogen decrepitation: decrepitating the quenched alloy hydrogen under a hydrogen pressure between 0.011 MPa for 0.524 h to obtain the powder. The present invention improves the manufacturing processes which are before the process of jet milling for omitting the process of jet milling, thus simplifying the process; which may also acquire a low cost production by efficiently using the precious rare earth resource.


A manufacturing method of rare earth magnet based on heat treatment of fine powder includes the following: an alloy for the rare earth magnet is firstly coarsely crushed and then finely crushed by jet milling to obtain a fine powder; the fine powder is heated in vacuum or in inert gas atmosphere at a temperature of 100 C.1000 C. for 6 minutes to 24 hours; then the fine powder is compacted under a magnet field and is sintered in vacuum or in inert gas atmosphere at a temperature of 950 C.1140 C. to obtain a sintered magnet; and machining the sintered magnet to obtain a magnet; then the magnet performs a RH grain boundary diffusion at a temperature of 700 C.1020 C. An oxidation film forms on the surface of all of the powder.


Patent
Xiamen Tungsten Co. | Date: 2016-05-26

The present invention discloses a low-B rare earth magnet. The rare earth magnet contains a main phase of R_(2)T_(14)B and comprises the following raw material components: 13.5 at %4.5 at % of R, 5.2 at %5.8 at % of B, 0.3 at %0.8 at % of Cu, 0.3 at %3 at % of Co, and the balance being T and inevitable impurities, the R being at least one rare earth element comprising Nd, and the T being an element mainly comprising Fe. 0.30.8 at % of Cu and an appropriate amount of Co are co-added into the rare earth magnet, so that three Cu-rich phases formed in the grain boundary, and the magnetic effect of the three Cu-rich phases existing in the grain boundary and the solution of the problem of insufficient B in the grain boundary can obviously improve the squareness and heat-resistance of the magnet.


The present invention discloses a manufacturing method of green compacts of rare earth alloy magnetic powder and a manufacturing method of rare earth magnet, it is a manufacturing method that pressing the rare earth alloy magnetic powder added with organic additive in a closed space filled with inert gases to manufacture the green compacts, wherein the rare earth alloy magnetic powder is compacted under magnetic field in a temperature atmosphere of 25 C.-50 C. and a relative humidity atmosphere of 10%-40%. This method is to set the temperature of the inert atmosphere in a fully closed space, inhibiting bad forming phenomenon of the magnet with low oxygen content (broken, corner-breakage, crack) after sintering, and increasing the degree of orientation, Br and (BH)max.


Patent
Xiamen Tungsten Co. | Date: 2016-06-17

The present invention discloses a W-containing RFeBCu serial sintered magnet and quenching alloy. The sintered magnet contains an R_(2)Fe_(14)B-type main phase, the R being at least one rare earth element comprising Nd or Pr; the crystal grain boundary of the rare earth magnet contains a W-rich area above 0.004 at % and below 0.26 at %, and the W-rich area accounts for 5.0 vol %11.0 vol % of the sintered magnet. The sintered magnet uses a minor amount of W pinning crystal to segregate the migration of the pinned grain boundary in the crystal grain boundary to effectively prevent abnormal grain growth and obtain significant improvement. The crystal grain boundary of the quenching alloy contains a W-rich area above 0.004 at % and below 0.26 at %, and the W-rich area accounts for at least 50 vol % of the crystal grain boundary.

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