CN108597707B - Ce-containing sintered magnet and preparation method thereof - Google Patents
Ce-containing sintered magnet and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a Ce-containing sintered magnet and a preparation method thereof. The Ce-containing sintered magnet is manufactured by double alloy, and the chemical formula of the Ce-containing sintered magnet is as follows by mass percent: [ Re ]100‑xCex]aFe100‑a‑b‑cBbTMcGad(ii) a Wherein X is more than or equal to 3.5 and less than or equal to 30, a is more than or equal to 28 and less than or equal to 33, b is more than or equal to 0.8 and less than or equal to 0.91, c is more than or equal to 0.5 and less than or equal to 3.5, and d/b is more than or equal to 0.3 and less than or equal to 0.8; re is rare earth element excluding Ce, and TM is one or more of Co, Al, Cu, Zr, Ti and Nb. According to the Ce-containing sintered magnet, the manufacturing cost of the magnet can be reduced by adding Ce, the microstructure of the magnet can be improved by matching of various elements and a preparation process, the coercive force of the magnet is improved, and therefore good comprehensive performance is obtained.
Description
Technical Field
The invention belongs to the field of magnet materials, and particularly relates to a Ce-containing sintered magnet with high coercivity and a preparation method thereof.
Background
The sintered Nd-Fe-B permanent magnetic material has the characteristics of high remanence, high magnetic energy product and the like, is widely applied to the fields of electronics, information, energy, traffic and the like, and is the permanent magnetic material with the best market prospect at present. In recent years, with the rapid development of new energy automobiles and high-efficiency energy-saving electric appliances, the demand for rare earth permanent magnet materials is increasing day by day.
Rare earth praseodymium and neodymium are main elements used for sintering neodymium iron boron, so that the cost of materials is increased and the utilization of rare earth resources is unbalanced after long-term use. The price of the Ce is less than one third of that of the Pr and Nd, so that the production cost is greatly reduced by developing the preparation of the Ce-containing sintered Nd-Fe-B magnet.
Chinese patent CN102800454 proposes a double-alloy method for preparing Ce-containing magnet, but the Ce content is higher, and excessive Ce enters the main phase more and generates more low-melting-point Ce2Fe14B main phase, and Ce2Fe14The magnetic moment Js and the anisotropy field HA of B are much lower than that of Nd2Fe14And B, the magnet is easy to grow in the sintering process, and the prepared magnet is low in coercive force and cannot meet the actual requirements of use under certain high-temperature conditions.
Disclosure of Invention
In order to solve the problems, the invention provides a Ce-containing sintered magnet and a preparation method thereof, wherein an A alloy contains Ce, a B alloy does not contain Ce, the proportion of Ga and B element components in the B alloy is controlled, the content of Ga is increased, and (Re-Ce) is formed at a crystal boundary in the magnet through a double-alloy method1Fe6The Ga phase reduces Ce element to enter the main phase and exists more at the grain boundary, so that the grain boundary phase better infiltrates the main phase, thereby improving the remanence and the coercive force of the magnet, improving the microstructure of the magnet and obtaining better magnet performance.
One of the purposes of the invention is to provide a Ce-containing sintered magnet, which has the chemical formula as follows by mass percent: [ Re ]100- xCex]aFe100-a-b-cBbTMcGad(ii) a Wherein X is more than or equal to 3.5 and less than or equal to 30, a is more than or equal to 28 and less than or equal to 33, b is more than or equal to 0.8 and less than or equal to 0.91, c is more than or equal to 0.5 and less than or equal to 3.5, and d/b is more than or equal to 0.3 and less than or equal to 0.8;
re is rare earth element excluding Ce, and TM is one or more of Co, Al, Cu, Zr, Ti and Nb.
The Ce-containing sintered magnet is prepared by mixing the alloy A and the alloy B;
the alloy A has a chemical formula as follows by mass percent:
[ReA 100-x1Cex1]a1Fe100-a1-b1-c1Bb1TMA c1wherein x1 is more than or equal to 10 and less than or equal to 90, a1 is more than or equal to 28 and less than or equal to 33, b1 is more than or equal to 0.8 and less than or equal to 1.0, c1 is more than or equal to 0.5 and less than or equal to 3.5, ReAAs rare earth elements excluding Ce, TMAIs one or more of Co, Al, Cu, Zr, Ti and Nb;
the chemical formula of the B alloy is as follows by mass percent:
ReB a2Fe100-a2-b2-c2-d2Bb2TMB c2Gad2wherein a2 is more than or equal to 28 and less than or equal to 33, b2 is more than or equal to 0.75 and less than or equal to 0.95, c2 is more than or equal to 0.5 and less than or equal to 3.5, d2/b2 is more than or equal to 0.25 and less than or equal to 0.9, ReBAs rare earth elements excluding Ce, TMBIs one or more of Co, Al, Cu, Zr, Ti and Nb.
In some embodiments of the present invention, the sum of the contents of Dy and Tb in the Ce-containing sintered magnet is 0.5 or less in mass%.
Preferably, the oxygen content in the Ce-containing sintered magnet is less than or equal to 2000 ppm.
Another object of the present invention is to provide a method for preparing a Ce-containing sintered magnet, comprising the steps of:
(1) preparing raw materials according to the components of the alloy A and the alloy B respectively,
the alloy A has a chemical formula as follows by mass percent:
[ReA 100-x1Cex1]a1Fe100-a1-b1-c1Bb1TMA c1wherein x1 is more than or equal to 10 and less than or equal to 90, a1 is more than or equal to 28 and less than or equal to 33, b1 is more than or equal to 0.8 and less than or equal to 1.0, c1 is more than or equal to 0.5 and less than or equal to 3.5, ReAAs rare earth elements excluding Ce, TMAIs one or more of Co, Al, Cu, Zr, Ti and Nb;
the chemical formula of the B alloy is as follows by mass percent:
ReB a2Fe100-a2-b2-c2-d2Bb2TMB c2Gad2wherein a2 is more than or equal to 28 and less than or equal to 33, b2 is more than or equal to 0.75 and less than or equal to 0.95, c2 is more than or equal to 0.5 and less than or equal to 3.5, d2/b2 is more than or equal to 0.25 and less than or equal to 0.9, ReBAs rare earth elements excluding Ce, TMBIs one or more of Co, Al, Cu, Zr, Ti and Nb;
(2) respectively smelting the prepared raw materials to obtain two alloy quick-setting sheets;
(3) respectively carrying out hydrogen breaking treatment on the two alloy quick-setting sheets, and then grinding fine powder in an air flow mill to obtain alloy A magnetic powder and alloy B magnetic powder, wherein the particle sizes of the alloy A magnetic powder and the alloy B magnetic powder are 1-7 mu m;
(4) mixing the alloy magnetic powder A and the alloy magnetic powder B according to the component requirements of the Ce-containing sintered magnet to obtain mixed magnetic powder;
(5) under the protective atmosphere of inert gas, the mixed magnetic powder is oriented and pressed in a magnetic field with the magnetic field intensity of 1.5-2.3T to form a blank;
(6) sintering the blank, and then tempering to obtain a Ce-containing sintered magnet, wherein the chemical formula of the Ce-containing sintered magnet is as follows by mass percent: [ Re ]100-xCex]aFe100-a-b-cBbTMcGad(ii) a Wherein X is more than or equal to 3.5 and less than or equal to 30, a is more than or equal to 28 and less than or equal to 33, b is more than or equal to 0.8 and less than or equal to 0.91, c is more than or equal to 0.5 and less than or equal to 3.5, and d/b is more than or equal to 0.3 and less than or equal to 0.8;
re is rare earth element excluding Ce, and TM is one or more of Co, Al, Cu, Zr, Ti and Nb.
In the step (2), the smelting is to put the prepared raw materials into a rapid hardening furnace, and the vacuum degree reaches 10-2Preheating when the pressure is above Pa, and when the vacuum degree reaches 10 again-2Stopping vacuumizing and filling high-purity Ar gas after the pressure is above Pa, and smelting after the Ar gas pressure in the furnace reaches-0.04 to-0.08 MPa relative to the standard atmospheric pressure; and after the raw materials are completely melted, performing electromagnetic stirring refining to obtain alloy liquid.
Preferably, the alloy liquid is poured onto a water-cooled copper roller with the linear speed of 2-4m/s to prepare the quick-setting sheet.
In some embodiments of the invention, the quick setting tablet has an average thickness of 0.3mm or less.
In the step (3), the particle size of the magnetic powder A is smaller than that of the magnetic powder B, and the difference between the particle size of the magnetic powder A and the particle size of the magnetic powder B is 0.1-3.0 mu m.
In the step (6), the sintering is sectional sintering, the sintering is carried out at a high temperature of 1000-1050 ℃, then the sintering is carried out at a low temperature of 900-1010 ℃, and then protective gas is filled for cooling or vacuum cooling; the tempering treatment is carried out for 1-4 h at 450-600 ℃.
According to the Ce-containing sintered magnet and the preparation method thereof, the magnet is prepared through double alloys; one is an alloy with higher Ga content, and the other is an alloy containing Ce, through the matching of different elements, more Ce exists at the crystal boundary of the magnet, the magnet has higher coercive force, and meanwhile, the requirement of certain high-temperature condition application can be met, and the cost for producing the magnet is reduced; by controlling the granularity of different alloy magnetic powder and utilizing the combination of segmented sintering and tempering, the growth of the crystal grain size of the magnet is inhibited, the microstructure of the magnet is improved, and the performance of the magnet is improved; the performance of the magnet can also be improved by controlling the oxygen content during the preparation process.
Detailed Description
The following detailed description of the present invention will be given in conjunction with examples to better understand the aspects of the present invention and the advantages of its various aspects. However, the specific embodiments and examples described below are for illustrative purposes only and are not limiting of the invention.
The embodiment of the invention provides a Ce-containing sintered magnet and a preparation method thereof, wherein the sintered magnet is prepared by mixing double alloys, one alloy has higher Ga content, the other alloy is an alloy containing Ce, through the matching of different components, more Ce exists in the crystal boundary of the magnet, the coercive force of the magnet and the squareness of a demagnetization curve are improved, and the magnet can meet the use requirement under a certain high temperature condition. The preparation process of the magnet avoids adding heavy rare earth, and the cost of the raw materials is reduced by adding Ce. The specific preparation process comprises the following steps:
(1) preparing raw materials according to the components of the alloy A and the alloy B respectively,
the alloy A has a chemical formula as follows by mass percent:
[ReA 100-x1Cex1]a1Fe100-a1-b1-c1Bb1TMA c1wherein x1 is more than or equal to 10 and less than or equal to 90, a1 is more than or equal to 28 and less than or equal to 33, b1 is more than or equal to 0.8 and less than or equal to 1.0, c1 is more than or equal to 0.5 and less than or equal to 3.5, ReAAs rare earth elements excluding Ce, TMAIs one or more of Co, Al, Cu, Zr, Ti and Nb;
the chemical formula of the B alloy is as follows by mass percent:
ReB a2Fe100-a2-b2-c2-d2Bb2TMB c2Gad2wherein a2 is more than or equal to 28 and less than or equal to 33, b2 is more than or equal to 0.75 and less than or equal to 0.95, c2 is more than or equal to 0.5 and less than or equal to 3.5, d2/b2 is more than or equal to 0.25 and less than or equal to 0.9, ReBAs rare earth elements excluding Ce, TMBIs one or more of Co, Al, Cu, Zr, Ti and Nb.
(2) Respectively smelting the prepared raw materials, specifically putting the prepared raw materials into a condensing furnace, and keeping the vacuum degree to 10-2Preheating when the pressure is above Pa, and when the vacuum degree reaches 10 again-2Stopping vacuumizing and filling high-purity Ar gas after the pressure is above Pa, and smelting after the Ar gas pressure in the furnace reaches-0.04 to-0.08 MPa relative to the standard atmospheric pressure; and after the raw materials are completely melted, performing electromagnetic stirring refining to obtain alloy liquid.
And pouring after smelting, specifically pouring the alloy liquid onto a water-cooled copper roller with the linear speed of 2-4m/s to prepare two alloy quick-setting sheets. The average thickness of the alloy rapid-hardening piece is 0.1-0.5mm, and the preferred average thickness is less than or equal to 0.3mm, so as to facilitate later processing.
(3) And respectively carrying out hydrogen crushing and dehydrogenation on the two alloy quick-setting sheets to obtain coarse crushed magnetic powder.
And carrying out jet milling on the coarsely crushed magnetic powder to obtain alloy A magnetic powder and alloy B magnetic powder, wherein the granularity of the alloy A magnetic powder and the alloy B magnetic powder is between 1 and 7 mu m. The granularity of the alloy A magnetic powder is smaller than that of the alloy B magnetic powder, and the difference between the granularity of the alloy A magnetic powder and the granularity of the alloy B magnetic powder is 0.1-3.0 mu m, namely, the granularity of the magnetic powder containing Ce is smaller than that of the magnetic powder not containing Ce.
The coarse, crushed magnetic powder may be suitably treated prior to the jet mill. Mixing the oxidation-resistant lubricant with the coarse crushed magnetic powder at a ratio of 1-7ml/kg under the protection gas to prevent agglomeration and oxidation of the magnetic powder in the subsequent jet milling process, and also to reduce the oxygen content in the final magnet.
(4) The component requirements of magnets of different brands are different, and according to the component requirements, the alloy magnetic powder A and the alloy magnetic powder B are mixed in a powder mixer to obtain uniformly mixed magnetic powder.
(5) And under the inert gas protection atmosphere, the mixed magnetic powder is oriented and pressed in a magnetic field with the magnetic field intensity of 1.5-2.3T to be molded and pressed into a blank.
(6) And sintering the blank, and then tempering to obtain the Ce-containing sintered magnet. The sectional sintering is carried out, wherein the sintering is carried out at a high temperature of 1000-1050 ℃, then the sintering is carried out at a low temperature of 900-1010 ℃, and then protective gas is filled for cooling or vacuum cooling. The tempering treatment is carried out for 1-4 h at 450-600 ℃ to obtain the final sintered magnet. In this example, low temperature sintering was achieved and only one tempering was required.
The chemical formula of the Ce-containing sintered magnet (final sintered magnet) is: [ Re ]100-xCex]aFe100-a-b- cBbTMcGad(ii) a Wherein X is more than or equal to 3.5 and less than or equal to 30, a is more than or equal to 28 and less than or equal to 33, b is more than or equal to 0.8 and less than or equal to 0.91, c is more than or equal to 0.5 and less than or equal to 3.5, and d/b is more than or equal to 0.3 and less than or equal to 0.8; re is rare earth element excluding Ce, and TM is one or more of Co, Al, Cu, Zr, Ti and Nb. The calculation shows that the Ce content in the final sintered magnet is about 1-10 wt%.
The total of Dy and Tb contents in the Ce-containing sintered magnet of this example was not more than 0.5 mass%. Preferably, Dy and Tb elements are not actively added during the production process, and Dy and Tb are not substantially contained in the sintered magnet.
The oxygen content in the sintered magnet containing Ce of the embodiment is less than or equal to 2000ppm, and the coercive force of the magnet can be improved by controlling the oxygen content. In the expression of the Ce-containing sintered magnet of the present invention, oxygen is not contained because the content of oxygen element in the sintered magnet is extremely small and negligible, but an increase in the oxygen content also affects the coercive force of the magnet. In the jet mill, the oxidation of magnetic powder is required to be reduced as much as possible.
In the embodiment, through the matching of all elements in the magnet, the control of the particle size of magnetic powder, the treatment of sintering and tempering processes and the control of oxygen content, the Ce-containing sintered magnet can reduce the Ce (cerium) element entering a main phase as much as possible, low-temperature sintering is realized, only one tempering is needed, the growth of grain size in the sintering process is inhibited, the microstructure of the magnet is improved, and the coercive force of the magnet is improved. The price of cerium metal in the market is only about one third of that of neodymium metal, so the addition of cerium can significantly reduce the cost of the magnet.
Example 1
(1) Respectively preparing raw materials according to the components of the alloy A and the alloy B; the alloy A comprises the following components in percentage by mass: [ Pr)15Nd15Ce70]28.5FebalB1.0Al0.3Co0.9Cu0.12(ii) a The B alloy comprises the following components in percentage by mass: (PrNd)32.9Feba lB0.85Al1.0Co0.9Cu0.12Zr0.12Ga0.55。
(2) Respectively smelting the prepared raw materials, putting the prepared raw materials into a crucible of a medium-frequency induction smelting rapid-hardening furnace, and keeping the vacuum degree to 10-2Preheating with electricity when Pa is above, and when the vacuum degree reaches 10 again-2Stopping vacuumizing and filling high-purity Ar gas after the pressure is above Pa, and smelting after the Ar gas pressure in the furnace reaches-0.04 to-0.08 MPa relative to the standard atmospheric pressure; and after the raw materials are completely melted, performing electromagnetic stirring refining to obtain alloy liquid.
And pouring after smelting, specifically pouring the alloy liquid onto a water-cooled copper roller with the linear speed of 2-4m/s to prepare two alloy quick-setting sheets. The average thickness of the alloy quick-setting piece is 0.3 mm.
(3) And respectively carrying out hydrogen breaking treatment on the two alloy quick-setting sheets, and dehydrogenating to obtain coarse broken magnetic powder.
And carrying out jet milling on the coarsely crushed magnetic powder to obtain alloy A magnetic powder and alloy B magnetic powder, wherein the granularity of the alloy A magnetic powder is about 3.2 mu m, and the granularity of the alloy B magnetic powder is about 3.8 mu m.
(4) Mixing the alloy A magnetic powder and the alloy B magnetic powder according to the mass ratio of 1:9, and mixing the alloy A magnetic powder and the alloy B magnetic powder in a powder mixer to obtain uniformly mixed magnetic powder.
(5) And under the inert gas protective atmosphere, carrying out orientation compression molding on the mixed magnetic powder in a magnetic field with the magnetic field intensity of 1.5T to obtain a blank.
(6) And sintering the blank, and then tempering to obtain the Ce-containing sintered magnet. The sectional sintering is carried out, wherein high-temperature sintering is carried out for 3 hours at 1000 ℃, then low-temperature sintering is carried out for 2 hours at 900 ℃, and then Ar gas is filled for cooling. Tempering treatment is carried out for 4 hours at 450 ℃ to obtain the final sintered magnet.
Example 1A
The procedure of example 1 was repeated except that "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 1: 9" in step (4) of example 1 was changed to "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 2: 8". The magnetic properties are shown in Table 2.
Example 1B
The procedure of example 1 was repeated except that "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 1: 9" in step (4) of example 1 was changed to "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 3: 7". The magnetic properties are shown in Table 2.
Example 1C
The procedure of example 1 was repeated except that "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 1: 9" in step (4) of example 1 was changed to "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 2: 3". The magnetic properties are shown in Table 2.
Example 1D
The procedure of example 1 was repeated except that "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 1: 9" in step (4) of example 1 was changed to "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 1: 1". The magnetic properties are shown in Table 2.
Comparative example 1
The procedure of example 1 was repeated except that "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 1: 9" in step (4) of example 1 was changed to "the alloy a magnetic powder and the alloy B magnetic powder were mixed at a mass ratio of 3: 2". The magnetic properties are shown in Table 2.
The composition of each of the sintered magnets is shown in Table 1.
TABLE 1
TABLE 2 magnetic Properties of the respective sintered magnets
The analysis in the table above shows that, as the content of cerium (Ce) increases, the coercivity of the magnet decreases sharply, the content exceeds 10 wt%, the coercivity of the magnet is lower than 13kOe, and the squareness of the magnet deteriorates.
The magnetic properties at a high temperature of 160 ℃ of some of the above sintered magnets are shown in Table 3.
TABLE 3
As can be seen from Table 3, the magnet containing a higher Ce content has better high temperature magnetic properties and better high temperature squareness. When the content of Ce exceeds 10 wt%, the high temperature magnetic properties of the magnet deteriorate. The reason for this is probably that double main phases are formed inside the magnet and influence each other in demagnetization, and the squareness of the high-temperature demagnetization curve is poor.
Example 2
(1) Respectively preparing raw materials according to the components of the alloy A and the alloy B; the alloy A comprises the following components in percentage by mass: [ Pr)25Nd25Ce50]30.5FebalB0.97Al1.2Co1.9Cu0.22(ii) a The B alloy comprises the following components in percentage by mass: (Pr)50Nd50)32.9Feba lB0.85Al1.2Co1.9Cu022Zr0.12Ga0.55。
(2) Respectively smelting the prepared raw materials, putting the prepared raw materials into a crucible of a medium-frequency induction smelting rapid hardening furnace, and controlling the vacuum degree to 10-2Preheating with electricity when Pa is above, and when the vacuum degree reaches 10 again-2Stopping vacuumizing and filling high-purity Ar gas after the pressure is above Pa, and smelting after the Ar gas pressure in the furnace reaches-0.04 to-0.08 MPa relative to the standard atmospheric pressure; and after the raw materials are completely melted, performing electromagnetic stirring refining to obtain alloy liquid.
And pouring after smelting, specifically pouring the alloy liquid onto a water-cooled copper roller with the linear speed of 2-4m/s to prepare two alloy quick-setting sheets. The average thickness of the alloy quick-setting piece is 0.35 mm.
(3) And respectively carrying out hydrogen breaking treatment on the two alloy quick-setting sheets, and dehydrogenating to obtain coarse broken magnetic powder.
And carrying out jet milling on the coarsely crushed magnetic powder to obtain alloy A magnetic powder and alloy B magnetic powder, wherein the granularity of the alloy A magnetic powder is about 3.5 mu m, and the granularity of the alloy B magnetic powder is about 4.1 mu m.
(4) Mixing the alloy A magnetic powder and the alloy B magnetic powder according to the mass ratio of 1:3, and mixing the alloy A magnetic powder and the alloy B magnetic powder in a powder mixer to obtain mixed magnetic powder.
(5) And under the inert gas protective atmosphere, carrying out orientation pressing forming on the mixed magnetic powder in a magnetic field with the magnetic field intensity of 2.3T to obtain a blank.
(6) And sintering the blank, and then tempering to obtain the Ce-containing sintered magnet. The sectional sintering is carried out, wherein high-temperature sintering is carried out for 2 hours at 1050 ℃, and then vacuum cooling is carried out after low-temperature sintering is carried out for 1 hour at 1010 ℃. The tempering treatment is carried out at 600 ℃ for 2 hours to obtain the final sintered magnet.
Comparative example 2
In step (1) of example 2:
composition of B alloy (Pr)50Nd50)32.9FebalB0.85Al1.2Co1.9Cu0.22Zr0.12Ga0.55The alloy B comprises the following components: (Pr)22Nd71Dy7)32.8FebalB0.97Al1.0Co0.7Cu0.48Zr0.06Ga0.08The other processes were the same as in example 2.
TABLE 4 Properties of the above sintered magnet
By contrast, under the condition of containing the same Ce content, the coercive force can be improved by adding a large amount of Ga element.
It should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. Furthermore, unless the context indicates otherwise, words that appear in the singular include the plural and vice versa. Additionally, all or a portion of any embodiment may be utilized with all or a portion of any other embodiment, unless stated otherwise.
Claims (9)
1. A Ce-containing sintered magnet is characterized in that the chemical formula thereof is as follows by mass percent: [ Re ]100-xCex]aFe100-a-b- cBbTMcGad(ii) a Wherein,
3.5≤X≤30，28≤a≤33，0.8≤b≤0.91，0.5≤c≤3.5，
0.3≤d/b≤0.8；
re is a rare earth element excluding Ce, and TM is one or more of Co, Al, Cu, Zr, Ti and Nb;
the Ce-containing sintered magnet is prepared by mixing an alloy A and an alloy B;
the alloy A has a chemical formula as follows by mass percent:
[ReA 100-x1Cex1]a1Fe100-a1-b1-c1Bb1TMA c1wherein x1 is more than or equal to 10 and less than or equal to 90, a1 is more than or equal to 28 and less than or equal to 33, b1 is more than or equal to 0.8 and less than or equal to 1.0, c1 is more than or equal to 0.5 and less than or equal to 3.5, ReAIs a rare earth element excluding Ce,TMAis one or more of Co, Al, Cu, Zr, Ti and Nb;
the chemical formula of the B alloy is as follows by mass percent:
ReB a2Fe100-a2-b2-c2-d2Bb2TMB c2Gad2wherein a2 is more than or equal to 28 and less than or equal to 33, b2 is more than or equal to 0.75 and less than or equal to 0.95, c2 is more than or equal to 0.5 and less than or equal to 3.5, d2/b2 is more than or equal to 0.25 and less than or equal to 0.9, ReBAs rare earth elements excluding Ce, TMBIs one or more of Co, Al, Cu, Zr, Ti and Nb.
2. The Ce-containing sintered magnet according to claim 1, wherein the sum of Dy and Tb contents in the Ce-containing sintered magnet is 0.5 or less in mass%.
3. The Ce-containing sintered magnet according to claim 1, wherein the oxygen content in the Ce-containing sintered magnet is 2000ppm or less.
4. A method for producing a sintered magnet containing Ce, characterized by comprising the steps of:
(1) preparing raw materials according to the components of the alloy A and the alloy B respectively,
the alloy A has a chemical formula as follows by mass percent:
[ReA 100-x1Cex1]a1Fe100-a1-b1-c1Bb1TMA c1wherein x1 is more than or equal to 10 and less than or equal to 90, a1 is more than or equal to 28 and less than or equal to 33, b1 is more than or equal to 0.8 and less than or equal to 1.0, c1 is more than or equal to 0.5 and less than or equal to 3.5, ReAAs rare earth elements excluding Ce, TMAIs one or more of Co, Al, Cu, Zr, Ti and Nb;
the chemical formula of the B alloy is as follows by mass percent:
ReB a2Fe100-a2-b2-c2-d2Bb2TMB c2Gad2wherein a2 is more than or equal to 28 and less than or equal to 33, b2 is more than or equal to 0.75 and less than or equal to 0.95, c2 is more than or equal to 0.5 and less than or equal to 3.5, d2/b2 is more than or equal to 0.25 and less than or equal to 0.9, ReBAs rare earth elements excluding Ce, TMBIs one or more of Co, Al, Cu, Zr, Ti and Nb;
(2) respectively smelting the prepared raw materials to obtain two alloy quick-setting sheets;
(3) respectively carrying out hydrogen breaking treatment on the two alloy quick-setting sheets, and then grinding fine powder in an air flow mill to respectively obtain alloy A magnetic powder and alloy B magnetic powder, wherein the particle sizes of the alloy A magnetic powder and the alloy B magnetic powder are between 1 and 7 mu m;
(4) mixing the alloy magnetic powder A and the alloy magnetic powder B according to the component requirements of the Ce-containing sintered magnet to obtain mixed magnetic powder;
(5) under the protective atmosphere of inert gas, the mixed magnetic powder is oriented and pressed in a magnetic field with the magnetic field intensity of 1.5-2.3T to form a blank;
(6) sintering the blank, and then tempering to obtain a Ce-containing sintered magnet, wherein the chemical formula of the Ce-containing sintered magnet is as follows by mass percent: [ Re ]100-xCex]aFe100-a-b-cBbTMcGad(ii) a Wherein X is more than or equal to 3.5 and less than or equal to 30, a is more than or equal to 28 and less than or equal to 33, b is more than or equal to 0.8 and less than or equal to 0.91, c is more than or equal to 0.5 and less than or equal to 3.5, and d/b is more than or equal to 0.3 and less than or equal to 0.8;
re is rare earth element excluding Ce, and TM is one or more of Co, Al, Cu, Zr, Ti and Nb.
5. The method according to claim 4, wherein in the step (2), the smelting is to put the prepared raw materials into a rapid hardening furnace, and the vacuum degree reaches 10-2Preheating when the pressure is above Pa, and when the vacuum degree reaches 10 again-2Stopping vacuumizing and filling high-purity Ar gas after the pressure is above Pa, and smelting after the Ar gas pressure in the furnace reaches-0.04 to-0.08 MPa relative to the standard atmospheric pressure; and after the raw materials are completely melted, performing electromagnetic stirring refining to obtain alloy liquid.
6. The method according to claim 5, wherein the molten alloy is cast onto a water-cooled copper roll at a line speed of 2 to 4m/s to produce a rapid-hardening tablet.
7. The method of claim 6, wherein the quick setting sheet has an average thickness of 0.3mm or less.
8. The method according to claim 4, wherein in step (3), the particle size of the A magnetic particles is smaller than that of the B magnetic particles by 0.1-3.0 μm.
9. The method according to claim 4, wherein in the step (6), the sintering is a step sintering, the sintering is carried out at a high temperature of 1000-1050 ℃, then the sintering is carried out at a low temperature of 900-1010 ℃, and then protective gas is filled for cooling or vacuum cooling; the tempering treatment is carried out for 1-4 h at 450-600 ℃.
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| CN104576028A (en) * | 2014-12-30 | 2015-04-29 | 四川大学 | Methods for manufacturing cerium-rich anisotropy nano-crystalline rare-earth permanent magnets |
| CN105575577A (en) * | 2016-03-04 | 2016-05-11 | 四川大学 | Sintered cerium-rich rare earth permanent magnetic material and preparation method thereof |
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| CN104576028A (en) * | 2014-12-30 | 2015-04-29 | 四川大学 | Methods for manufacturing cerium-rich anisotropy nano-crystalline rare-earth permanent magnets |
| CN105575577A (en) * | 2016-03-04 | 2016-05-11 | 四川大学 | Sintered cerium-rich rare earth permanent magnetic material and preparation method thereof |
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