WO2022006912A1 - Auxiliary alloy powder for permanent magnet material and preparation method therefor, and permanent magnet material - Google Patents

Abstract

An auxiliary alloy powder used for a rare earth material and a preparation method therefor. The preparation method involves subjecting a hydrogen absorption alloy, as an alloy raw material, to smelting to obtain an auxiliary alloy intermediate, subjecting the auxiliary alloy intermediate to hydrogen crushing to obtain auxiliary alloy particles, and subjecting the auxiliary alloy particles to jet milling to obtain an auxiliary alloy powder. The auxiliary alloy powder is formed from an alloy raw material at a specific ratio, has a better hydrogen absorption performance, and can be more rapidly crushed during hydrogen crushing to obtain a more uniform powder with a smaller particle size, such that the technical problem of the introduction of impurities caused by an excessively long preparation process is avoided.

Description

Auxiliary alloy powder for permanent magnet material and preparation method thereof, permanent magnet material technical field

The invention relates to the field of rare earth permanent magnet materials, in particular to a preparation method of auxiliary alloy powder for rare earth permanent magnet materials, auxiliary alloy powder for rare earth permanent magnet materials prepared by the method, and rare earth prepared by using the auxiliary alloy powder Permanent magnet material.

Background technique

At present, the application of rare earth permanent magnet materials is increasingly widespread. At the same time, new energy and environmental protection are increasingly concerned and become an inevitable development trend. Therefore, high coercivity requirements are put forward for the rare earth permanent magnet materials used.

Rare earth permanent magnet materials generally include a main phase and an auxiliary phase, and the auxiliary phase is generally alloy powder. In the prior art, materials of some special elements, such as transition metal elements such as Co, Cu, Al, Zr, Nb, and rare earth elements such as Pr, Dy, Tb, Gd, and Ho, are added during the preparation (smelting metallurgy) of the auxiliary phase. When using this auxiliary phase to prepare rare earth permanent magnet materials, these elements can partially or completely exist in the main phase grains. Therefore, the auxiliary phase containing special elements and the main phase neodymium containing NdFeB grain units are used. Mixed sintering of iron and boron powders can produce rare earth permanent magnet materials with excellent performance.

technical problem

The existing preparation processes of auxiliary phases containing special elements are mainly coarse crushing-ball milling and coarse crushing-screening-jet mill. The contact of the alloy particles with oxygen seriously affects the final properties of the prepared rare earth permanent magnet material, such as reducing the coercive force of the rare earth permanent magnet material.

technical solutions

In view of this, it is necessary to provide a new preparation method of auxiliary alloy powder for permanent magnet materials to solve the above problems.

In addition, it is also necessary to provide an auxiliary alloy powder prepared by the above-mentioned preparation method of auxiliary alloy powder.

In addition, it is also necessary to provide a permanent magnet material prepared by using the above-mentioned auxiliary alloy powder.

A preparation method of auxiliary alloy powder, which comprises the steps:

Step S1: configure an alloy raw material, the alloy raw material includes a hydrogen absorbing alloy, the hydrogen absorbing alloy includes a component R and a component A, and the atomic content ratio of the component R and the component A is 1:2-1:3; the component A It is one of Fe and Co or a mixture of the two in any ratio; the component R is a rare earth element;

Step S2: smelting the alloy raw material to obtain an auxiliary alloy intermediate;

Step S3: the above-mentioned auxiliary alloy intermediate is crushed with hydrogen to obtain auxiliary alloy particles;

Step S4: Perform jet milling on the auxiliary alloy particles to obtain auxiliary alloy powder.

Preferably, in the step S2, the alloy raw material is smelted by means of ingot casting or stripping.

Preferably, the step S3 includes:

S31: put the above-mentioned auxiliary alloy intermediate into the hydrogen heat treatment furnace, open the vacuum system and evacuate until the pressure in the furnace is the first pressure;

S32: Fill the hydrogen heat treatment furnace with hydrogen to make the gas pressure in the furnace reach the second gas pressure and keep the second gas pressure until the auxiliary alloy intermediate is saturated with hydrogen absorption, so that the auxiliary alloy intermediate absorbs hydrogen and is broken into auxiliary alloy particles.

Preferably, the first air pressure is less than or equal to 5×10 ^-3 Pa.

Preferably, the second air pressure is 0.1 Mpa.

Preferably, the alloy raw material further includes a transition metal, and the transition metal is one or more of Cu, Al, Zr and Nb.

Preferably, in the alloy raw material, the mass percentage content of the transition metal is in the range of 0-10%.

An auxiliary alloy powder prepared by the above-mentioned preparation method of auxiliary alloy powder.

A permanent magnet material is prepared by mixing the above-mentioned auxiliary alloy powder with the main phase alloy powder and performing sintering and tempering processes in sequence.

Preferably, the mass percentage content of the auxiliary alloy powder in the permanent magnet material is less than or equal to 5%.

Preferably, the main phase alloy powder is NdFeB powder.

beneficial effect

The auxiliary alloy powder of the invention adopts a specific proportion of alloy raw materials, which has better hydrogen absorption performance, and can be pulverized more quickly when hydrogen is pulverized to obtain more uniform powder with smaller particle size, thereby avoiding the excessively long preparation process. Technical issues with the introduction of impurities.

Description of drawings

FIG. 1 is a flow chart of the preparation of auxiliary alloy powder according to a preferred embodiment of the present invention.

FIG. 2 is a flow chart of the preparation of the permanent magnet material according to the preferred embodiment of the present invention.

The following specific embodiments will further illustrate the present invention in conjunction with the above drawings.

BEST MODE FOR CARRYING OUT THE INVENTION

In order to make those skilled in the art better understand the technical solution of the present invention, the product of the present invention will be described in further detail below with reference to the embodiments and accompanying drawings.

Referring to FIG. 1, a preferred embodiment of the present invention provides a method for preparing auxiliary alloy powder, which includes the following steps:

Step S1: configure an alloy raw material, the alloy raw material includes a hydrogen absorbing alloy, the hydrogen absorbing alloy includes a component R and a component A, and the atomic content ratio of the component R and the component A is 1:2-1:3; the component A It is one of Fe and Co or a mixture of the two in any ratio, wherein the component R is a rare earth element, including: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium , thulium, ytterbium, lutetium, scandium or yttrium. Specifically, the atomic content ratio of the component R and the component A is 1:2 or 1:3.

Step S2: smelting the alloy raw material using conventional ingot casting or stripping process to obtain an auxiliary alloy intermediate, which is an auxiliary alloy block or an auxiliary alloy sheet;

Step S3: The above-mentioned auxiliary alloy intermediate is crushed with hydrogen to obtain auxiliary alloy particles. The specific steps are: put the above-mentioned auxiliary alloy intermediate into the hydrogen heat treatment furnace, turn on the vacuum system to evacuate until the pressure in the furnace is the first pressure, and then fill the hydrogen heat treatment furnace with hydrogen to make the pressure in the furnace reach the second pressure and The second gas pressure is maintained for a period of time T, so that the auxiliary alloy intermediate absorbs hydrogen and is broken into auxiliary alloy particles. After the auxiliary alloy intermediate is saturated with hydrogen, the residual hydrogen in the furnace is drawn out, and then the furnace is filled with inert gas and taken out. For auxiliary alloy particles, the first gas pressure is less than or equal to 5×10 ^-3 Pa, the second gas pressure is 0.1Mpa, and in at least one embodiment, the time T is 1 hour;

Step S4: Putting the above-mentioned auxiliary alloy particles into an air-flow mill for air-flow milling to obtain auxiliary alloy powder, and the particle size of the auxiliary alloy powder is less than or equal to 1.6 μm.

In the above step S1, on the premise of not affecting the 1:2 and 1:3 alloy phase formation of component R and component A, the alloy raw material may also include transition metals, and the transition metals include but are not limited to Cu, Al, Zr and one or more of Nb. In the alloy raw material, the mass percentage content of the transition metal is in the range of 0-10%.

The auxiliary alloy powder of the invention adopts a specific proportion of alloy raw materials, which has better hydrogen absorption performance, and can be pulverized more quickly when hydrogen is pulverized to obtain more uniform powder with smaller particle size, thereby avoiding the excessively long preparation process. Technical issues with the introduction of impurities.

As shown in FIG. 2, the present invention also provides a permanent magnet material, which is formed by mixing the above-mentioned auxiliary alloy powder and main phase alloy powder under the protection of an inert gas into a mixed powder; molding the mixed powder Orientation, and then carry out the conventional sintering and tempering process in turn. The sintering process is to put it into a vacuum sintering furnace for sintering and densification, and the tempering process needs to go through multiple tempering processes. In at least one embodiment, the auxiliary alloy powder and the main phase alloy powder are mixed under the protection of an inert gas. The mass percentage of auxiliary alloy powder is less than or equal to 5%. The main phase alloy powder may be NdFeB powder. In at least one embodiment, the main phase of the NdFeB powder is Nd ₂ Fe ₁₄ B.

The present invention will be specifically described below through specific examples, which are only preferred embodiments of the present invention, and are not intended to limit the present invention.

Example 1

Alloy raw material Pr ₁ Co _{2 is prepared} , and the alloy raw material is smelted by a conventional ingot casting process to obtain an auxiliary alloy block.

Put the above-mentioned auxiliary alloy block into the hydrogen heat treatment furnace, open the vacuum system to evacuate to the furnace pressure of 5 × 10 ^-3 Pa, then fill the hydrogen heat treatment furnace with hydrogen to make the furnace pressure reach 0.1Mpa and keep it for 1 hour, The auxiliary alloy particles are obtained, the residual hydrogen in the furnace is extracted, and the furnace is filled with inert gas to take out the auxiliary alloy particles.

The above-mentioned auxiliary alloy particles were put into a jet mill for jet milling to obtain auxiliary alloy powders for permanent magnet materials with a particle size of 1.6 μm.

The above-mentioned auxiliary alloy powder for rare earth permanent magnet material and _{NdFeB powder with the chemical formula of Nd 2} Fe ₁₄ B are mixed in a mass ratio of 2:98 under the protection of an inert gas, and after mixing, the forming orientation is performed and then a conventional sintering and tempering process is performed, The permanent magnet material is obtained.

Example 2

The alloy raw material Dy ₁ Co _{2 is provided} , and the alloy raw material is smelted using a conventional ingot casting process to obtain an auxiliary alloy ingot.

Put the above-mentioned auxiliary alloy block into the hydrogen heat treatment furnace, open the vacuum system to evacuate to the furnace pressure of 5 × 10 ^-3 Pa, then fill the hydrogen heat treatment furnace with hydrogen to make the furnace pressure reach 0.1Mpa and keep it for 1 hour, The auxiliary alloy particles are obtained, the residual hydrogen in the furnace is extracted, and the furnace is filled with inert gas to take out the auxiliary alloy particles.

The above-mentioned auxiliary alloy particles were put into a jet mill for jet milling to obtain auxiliary alloy powder for permanent magnet materials with a particle size of 1.58 μm.

The above-mentioned auxiliary alloy powder for rare earth permanent magnet materials and _{NdFeB powder with chemical formula Nd 2} Fe ₁₄ B are mixed in a mass ratio of 2:98 under the protection of inert gas, and after mixing, they are shaped and oriented, and then conventional sintering and tempering are carried out. process to obtain permanent magnet materials.

The remanence, coercive force, magnetic energy product, squareness and density were tested on the NdFeB powders used in the above-mentioned Examples 1 and 2 and the prepared permanent magnet materials. The test results are shown in Table 1.

Table I:

	Remanence/KGs	Coercivity/KOe	Magnetic energy product/MGsOe	Squareness	density
NdFeB powder	13.57	15.02	43.77	0.83	7.50
Example 1	13.53	16.60	44.07	0.85	7.51
Example 2	13.27	18.84	42.44	0.84	7.52

It can be seen from the above table that the permanent magnet material prepared by the auxiliary alloy powder and the main phase alloy powder in Example 1 has an increase of 1.58 KOe in coercive force without adding heavy rare earth metals and the remanence is hardly reduced. The rare earth permanent magnet material prepared by the auxiliary alloy powder containing heavy rare earth and the main phase alloy powder in Example 2 has an obvious coercivity improvement effect, and the coercivity improvement per 1% Dy reaches 3.2 KOe.

The auxiliary alloy powder of the invention adopts a specific proportion of alloy raw materials, which has better hydrogen absorption performance, and can be pulverized more quickly when hydrogen is pulverized to obtain more uniform powder with smaller particle size, thereby avoiding the excessively long preparation process. Technical issues with the introduction of impurities.

The auxiliary alloy powder of the present invention is crushed by hydrogen in a vacuum furnace in an environment without air and impurities, so the obtained auxiliary alloy particles will not be polluted by air and impurities, and have higher purity and lower Oxygen content, so that the auxiliary alloy powder for rare earth permanent magnet material obtained by jet milling has higher purity and lower oxygen content, so that the rare earth permanent magnet material prepared from the auxiliary alloy powder has higher coercivity. In addition, the preparation process of the auxiliary alloy powder for rare earth permanent magnet materials of the present invention is simple and low in cost.

In addition, the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the preferred embodiments of the present invention have been disclosed as above, they are not intended to limit the present invention. Those skilled in the art, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above. Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence of the invention still fall within the scope of the technical solutions of the present invention.

Claims (11)

1. A preparation method of auxiliary alloy powder is characterized in that: comprises the following steps:

   Step S1: configure an alloy raw material, the alloy raw material includes a hydrogen absorbing alloy, the hydrogen absorbing alloy includes a component R and a component A, and the atomic content ratio of the component R and the component A is 1:2-1:3; the component A It is one of Fe and Co or a mixture of the two in any ratio; the component R is a rare earth element;

   Step S2: smelting the alloy raw material to obtain an auxiliary alloy intermediate;

   Step S3: the above-mentioned auxiliary alloy intermediate is crushed with hydrogen to obtain auxiliary alloy particles;

   Step S4: Perform jet milling on the auxiliary alloy particles to obtain auxiliary alloy powder.
2. The method for preparing auxiliary alloy powder according to claim 1, characterized in that: in the step S2, the alloy raw material is smelted by means of ingot casting or stripping.
3. The method for preparing auxiliary alloy powder according to claim 1, wherein the step S3 comprises:

   S31: put the above-mentioned auxiliary alloy intermediate into the hydrogen heat treatment furnace, open the vacuum system and evacuate until the pressure in the furnace is the first pressure;

   S32: Fill the hydrogen heat treatment furnace with hydrogen to make the gas pressure in the furnace reach the second gas pressure and keep the second gas pressure until the auxiliary alloy intermediate is saturated with hydrogen absorption, so that the auxiliary alloy intermediate absorbs hydrogen and is broken into auxiliary alloy particles.
4. The method for preparing auxiliary alloy powder according to claim 3, wherein the first gas pressure is less than or equal to 5×10 ^-3 Pa.
5. The method for preparing auxiliary alloy powder according to claim 3, wherein the second gas pressure is 0.1Mpa.
6. The method for preparing auxiliary alloy powder according to claim 1, wherein the alloy raw material further comprises a transition metal, and the transition metal is one or more of Cu, Al, Zr and Nb.
7. The method for preparing auxiliary alloy powder according to claim 6, characterized in that: in the alloy raw material, the mass percentage content of the transition metal is in the range of 0-10%.
8. An auxiliary alloy powder, characterized in that: the auxiliary alloy powder is prepared by the preparation method of the auxiliary alloy powder according to any one of claims 1-7.
9. A permanent magnet material, which is obtained by mixing auxiliary alloy powder and main phase alloy powder, forming orientation, and performing sintering and tempering processes in sequence, characterized in that: the auxiliary alloy powder is prepared by any one of claims 1 to 7. The preparation method of the auxiliary alloy powder is obtained.
10. The permanent magnet material according to claim 9, wherein the mass percentage of the auxiliary alloy powder in the permanent magnet material is less than or equal to 5%.
11. The permanent magnet material according to claim 9, wherein the main phase alloy powder is NdFeB powder.