Permanent magnetic ferrite material as well as preparation method and application thereof

Abstract

The invention provides a permanent magnetic ferrite material and a preparation method and application thereof, the permanent magnetic ferrite material comprises a main component and a secondary additive, the main component comprises A1-xRxFe2n-yMyO19, x is 0.4-0.6, y is 0.2-0.5, n is 5.0-5.8, A comprises Ca and Sr according to a molar ratio of (0.35-0.55): (0.045-0.15), R comprises a rare earth element, and M comprises Co; the secondary additive is composed of a Si-containing compound, a Ca-containing compound and a Sr-containing compound. According to the permanent magnetic ferrite material disclosed by the invention, components with specific components are added into the secondary additive, so that the squareness of the permanent magnetic ferrite material can be remarkably improved under the condition that a precursor with magnetic performance is ensured, and meanwhile, the use of a high-valence element cobalt is reduced under the condition that performance requirements are met.

Description

Technical Field

[0001] The invention belongs to the technical field of permanent magnetic ferrite materials and relates to a permanent magnetic ferrite material and a preparation method and application thereof. Background Art

[0002] In recent years, with the continuous improvement of economic level and the rapid development of electronic information technology industry, permanent ferrites are indispensable for generators and motors in the motor field, nuclear magnetic resonance in the medical industry, electrical instruments and industrial equipment, etc. For example, each car requires a large number of ferrite permanent magnet motors, so in terms of miniaturization and weight reduction of automobile rotors, higher requirements are put forward for ferrite magnets with higher magnetic properties, which further increases the demand for permanent ferrites.

[0003] Permanent ferrite is manufactured through a series of related ceramic processes such as pre-sintering, molding, and sintering. It has good properties such as high coercivity, high remanence, high magnetic energy product, and high magnetic flux density. The most notable feature is that permanent ferrite is magnetized immediately after a magnetic field is applied, and can maintain a constant magnetic function. However, there are many strontium ferrite products, but high-performance products are lacking.

[0004] At the same time, in practical applications, in addition to paying attention to the conventional parameters of permanent ferrite such as remanence, coercive force, magnetic flux, etc., the permanent magnet industry has also begun to pay attention to issues such as squareness, resistance and magnetic permeability that were less concerned in the past.

[0005] Based on the above research, it is necessary to provide a permanent magnet ferrite material, which has high squareness and other excellent magnetic properties. Summary of the invention

[0006] The object of the present invention is to provide a permanent magnet ferrite material and a preparation method and application thereof. The permanent magnet ferrite material can significantly improve the squareness of the permanent magnet ferrite material while ensuring the precursor of magnetic properties by adding components of specific composition to the secondary additives, and at the same time reduce the use of high-priced element cobalt while meeting performance requirements.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a permanent magnet ferrite material, the permanent magnet ferrite material comprises a main component and a secondary additive, the main component comprises A 1-x R x Fe 2n-y M y O 19 , wherein x is 0.4-0.6, y is 0.2-0.5, n is 5.0-5.8, A includes Ca and Sr in a molar ratio of (0.35-0.55):(0.045-0.15), R includes a rare earth element, and M includes Co;

[0009] The secondary additive consists of a Si-containing compound, a Ca-containing compound and a Sr-containing compound.

[0010] The present invention optimizes the composition of the permanent magnet ferrite material, and the secondary additive is composed of a Si-containing compound, a Ca-containing compound and a Sr-containing compound, especially a Ca-containing compound and a Sr-containing compound. Under the condition of meeting the requirements of other magnetic properties of the permanent magnet ferrite material, the squareness of the permanent magnet ferrite material can be improved and the use of the high-priced element cobalt can be reduced.

[0011] The x is 0.4-0.6, for example, 0.4, 0.45, 0.5, 0.55 or 0.6, y is 0.2-0.5, for example, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 or 0.5, n is 5.0-5.8, for example, 5.0, 5.05, 5.1, 5.15, 5.2, 5.25, 5.3, 5.35, 5.4, 5.45, 5.5, 5.55, 5.6, 5.65, 5.7, 5.75 or 5.8, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0012] The A includes Ca and Sr in a molar ratio of (0.35-0.55):(0.045-0.15), for example, 0.35:0.15, 0.40:0.1, 0.45:0.05, 0.5:0.1 or 0.55:0.045. When A includes only Ca and Sr, the chemical formula of the main component is Ca a Sr b R x Fe 2n-y M y O 19 , wherein a is 0.35-0.55, for example, 0.35, 0.4, 0.45, 0.5 or 0.55, and b is 0.045-0.15, for example, 0.045, 0.05, 0.055, 0.06, 0.065, 0.07, 0.075, 0.08, 0.085, 0.09, 0.095, 0.1 or 0.15, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] Preferably, n is 5.1-5.3, for example, 5.1, 5.15, 5.2, 5.25 or 5.3, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] Preferably, the A also includes Ba.

[0015] Preferably, the R also includes Bi.

[0016] Preferably, the M further includes any one of Mn, Mg, Ni, Cu or Zn, or a combination of at least two thereof.

[0017] Preferably, the Si-containing compound is 0.4-0.45wt% of the main component, for example, it can be 0.4wt%, 0.425wt% or 0.45wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, the Ca-containing compound is 0.1-0.5wt% of the main component, for example, it can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt% or 0.5wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the Sr-containing compound is 0.5-0.6wt% of the main component, for example, it can be 0.5wt%, 0.55wt% or 0.6wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] The Si-containing compound of the present invention includes SiO2, the Ca-containing compound includes CaO, and the Sr-containing compound includes SrO.

[0021] In a second aspect, the present invention provides a method for preparing the permanent magnet ferrite material as described in the first aspect, the preparation method comprising the following steps:

[0022] (1) mixing and pre-calcining the iron source, A source, R source and M source according to the formula amount of the main components to obtain a pre-calcined material;

[0023] (2) crushing the pre-sintered material in step (1) to obtain a crushed material, and performing secondary mixing, molding and sintering on the crushed material and the secondary additive to obtain the permanent magnet ferrite material;

[0024] The secondary additive consists of a silicon source, a calcium source and a strontium source.

[0025] The present invention first prepares a pre-burned material according to the formula of the main component, then crushes the pre-burned material and mixes it with a silicon source, a calcium source and a strontium source again, shapes it and sinters it. On the basis of a specific formula of the main component, a secondary additive of a specific composition improves the squareness of the permanent magnet ferrite material.

[0026] Preferably, the pre-sintering method in step (1) includes microwave sintering.

[0027] The present invention adopts microwave sintering for pre-sintering, which can improve the heating efficiency, improve the uniformity and yield of the product, and improve the microstructure and performance of the sintered material. Compared with the conventional sintering method, the sintering temperature is reduced. At the same time, the rapid heating of microwave sintering can inhibit the growth of grain structure, obtain ultrafine grain structure material, and significantly improve the microstructure of the material.

[0028] Preferably, the pre-burning temperature in step (1) is 1100-1250°C, for example, 1100°C, 1150°C, 1200°C or 1250°C, and the pre-burning time is 0.5-3h, for example, 0.5h, 1h, 1.5h, 2h, 2.5h or 3h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the average particle size of all raw materials before the one-time mixing in step (1) is not greater than 2 μm, for example, it can be 2 μm, 1.5 μm, 1 μm or 0.5 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] All the raw materials before the primary mixing described in the present invention refer to the iron source, the A source, the R source and the M source.

[0031] Preferably, the primary mixing in step (1) comprises wet mixing.

[0032] Preferably, the average particle size of the particles obtained by the one-time mixing in step (1) does not exceed 0.8 μm, for example, it can be 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm or 0.2 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] Preferably, the silicon source in step (2) is 0.4-0.45wt% of the crushed material, for example, it can be 0.4wt%, 0.425wt% or 0.45wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the calcium source in step (2) is 0.1-0.5wt% of the crushed material, for example, it can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt% or 0.5wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the strontium source in step (2) is 0.5-0.6wt% of the crushed material, for example, it can be 0.5wt%, 0.55wt% or 0.6wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the silicon source in step (2) comprises SiO2;

[0037] Preferably, the calcium source in step (2) comprises CaCO3;

[0038] Preferably, the strontium source in step (2) comprises SrCO3.

[0039] Preferably, a dispersant is also added during the crushing in step (2).

[0040] The present invention adds a dispersant when the pre-burned material is crushed, and the obtained crushed material is then subjected to subsequent secondary wet mixing with the secondary additive. Compared with a method of directly subjecting the pre-burned material, the secondary additive and the dispersant to secondary wet mixing, the granular dispersant can be crushed into powder in advance and better mixed with the pre-burned material.

[0041] Preferably, the added amount of the dispersant is 0-1wt% of the pre-sintered material, but does not include 0wt%. For example, it can be 0.1wt%, 0.3wt%, 0.5wt%, 0.7wt%, 0.9wt% or 1wt%, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, the crushing method in step (2) includes dry crushing, and the crushed material has an average particle size of 3-5 μm, for example, it can be 3 μm, 4 μm or 5 μm, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] Preferably, the secondary mixing method in step (2) includes wet ball milling, and the average particle size of the particles is less than 0.75 μm, for example, it can be 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm or 0.2 μm. Preferably, the average particle size of the particles is 0.5-0.7 μm, for example, it can be 0.5 μm, 0.6 μm or 0.7 μm, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, the secondary mixing time in step (2) is 16-24 h, for example, 16 h, 18 h, 20 h, 22 h or 24 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable, preferably 18-20 h.

[0045] Preferably, the solid content of the mixture obtained by the secondary mixing in step (2) is adjusted to 55-75wt% before molding, for example, it can be 55wt%, 60wt%, 65wt%, 70wt% or 75wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] Preferably, the forming in step (2) is carried out in a magnetic field of 14000-15000 Oe, for example, 14000 Oe, 14500 Oe or 15000 Oe, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0047] Preferably, after the molding in step (2) and before sintering, a heat treatment is performed to remove the dispersant of the present invention.

[0048] Preferably, the heat treatment temperature is 100-600°C, for example, 100°C, 200°C, 300°C, 400°C, 500°C or 600°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] Preferably, the sintering in step (2) is carried out in an oxygen-containing atmosphere.

[0050] Preferably, the sintering temperature in step (2) is 1150-1250°C, for example, 1150°C, 1200°C or 1250°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0051] Preferably, the sintering time in step (2) is 0.5-3 h, for example, 0.5 h, 1 h, 2 h or 3 h, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 0.5-2 h.

[0052] In a third aspect, the present invention provides an application of the permanent magnet ferrite material as described in the first aspect, wherein the application includes use in motor equipment.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] The present invention accurately optimizes the composition of the permanent magnet ferrite material and simultaneously makes the secondary additives consist of Si-containing compounds, Ca-containing compounds and Sr-containing compounds. Under the premise of meeting the requirements of other properties of the permanent magnet ferrite material, the squareness of the permanent magnet ferrite material can be improved and the use of the high-priced element cobalt can be reduced. DETAILED DESCRIPTION

[0055] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0056] The purity and particle size of the raw materials used in this embodiment are as follows: Fe2O3 powder (purity: 99.3wt%, average particle size of raw materials: 1.5μm);

[0057] SrCO3 powder (purity: 98.0wt%, original average particle size of raw material: 1.8μm);

[0058] SiO2 powder (purity: 99wt%, average particle size of raw material: 2.0μm);

[0059] La2O3 powder (purity: 99wt%, average particle size of raw material: 2.0μm);

[0060] CaCO3 powder (purity: 98.5wt%, original average particle size of raw material: 1.8μm);

[0061] Co2O3 powder (purity: 99wt%, average particle size of raw material: 2.0μm).

[0062] Example 1

[0063] This embodiment provides a permanent magnet ferrite material, and the preparation method of the permanent magnet ferrite material comprises the following steps:

[0064] (1) According to Sr 0.05 Ca 0.45 La 0.5 Fe 11.1 Co 0.3 Weigh the corresponding raw materials, including 485.3g of iron red, 4.14g of strontium carbonate, 24.79g of calcium carbonate, 44.6g of lanthanum oxide, and 13.49g of cobalt oxide. Add the weighed raw materials into a ball mill, add 840mL of water, mix and stir for 5 hours, and the average particle size of the slurry particles after mixing is 0.5μm;

[0065] The wet mixed granular material is dried and pre-fired in an oxygen-rich atmosphere to obtain a pre-fired material, wherein the pre-fired temperature is 1250° C., the heat preservation time is 1 hour, and the pre-fired method is microwave sintering;

[0066] (2) adding 0.2 wt% of calcium gluconate as an organic dispersant to the pre-sintered particles, and then dry-crushing the pre-sintered particles in a continuous dry vibration ball mill for 5 minutes, wherein the average particle size of the powder after crushing is 5.0 μm;

[0067] Weigh 450g of the crushed material, add 0.45wt% SiO2 powder, 0.1wt% CaCO3 powder, and 0.6wt% SrCO3 powder to the crushed material, then add 680ml of deionized water as the ball milling medium, carry out wet primary ball milling in a primary ball mill with a steel ball diameter of 6mm for 4 hours, and then transfer to a secondary ball mill with a steel ball diameter of 4mm for secondary ball milling for 12 hours. The average particle size of the slurry particles after two-stage ball milling is 0.65μm.

[0068] After ball milling, the water content in the obtained slurry is adjusted to a solid content of 70wt%, and the slurry is molded in a 15000Oe magnetic field to obtain a cylinder with a diameter of 43.2mm and a height of 12mm, and the molding pressure is 4MPa; the molded body is heat treated at a temperature of 300°C to completely remove the organic dispersant, and then sintered in an oxygen-rich atmosphere at a heating rate of 150°C / hour, and the sintering temperature is kept at 1210°C for 1 hour, and then the upper and lower surfaces of the sample are ground to obtain the permanent magnet ferrite material.

[0069] In the permanent magnet ferrite material obtained in this embodiment, the element contents of the pre-sintered material are shown in the following table:

[0070]

[0071]

[0072] Two permanent magnet ferrite materials were prepared by the preparation method described in this embodiment, and the magnetic properties and squareness were tested. The test results are as follows:

[0073] serial number Br(Gs) Hcb(Oe) Hcj(Oe) BHm(MGOe) Sintering temperature(℃) Squareness 1 4212 3648.5 4392 4.359 1210 0.7061 2 4203 3541.1 4179.6 4.392 1210 0.7233

[0074] Example 2

[0075] This embodiment provides a permanent magnet ferrite material, and the preparation method of the permanent magnet ferrite material comprises the following steps:

[0076] (1) According to Sr 0.046 Ca 0.492 La 0.461 Fe 10.15 Co 0.279 Weigh the corresponding raw materials, including 485.3g of iron oxide red, 4.2g of strontium carbonate, 29.66g of calcium carbonate, 45g of lanthanum oxide, and 13.7g of cobalt oxide. Add the weighed raw materials into a ball mill, add 840mL of water, mix and stir for 5 hours, and the average particle size of the slurry particles after mixing is 0.7μm;

[0077] The wet mixed granular material is dried and pre-fired in an oxygen-rich atmosphere to obtain a pre-fired material, wherein the pre-fired temperature is 1100° C., the heat preservation time is 2 hours, and the pre-fired method is microwave sintering;

[0078] (2) adding 1 wt% of the organic dispersant calcium gluconate to the pre-sintered particles, and then dry-crushing the pre-sintered particles in a continuous dry vibration ball mill for 5 minutes, and the average particle size of the powder after crushing is 3 μm;

[0079] Weigh 450g of the above-mentioned powder, add 0.4wt% SiO2 powder, 0.5wt% CaCO3 powder, and 0.6wt% SrCO3 powder, and then add 680ml of deionized water as a ball milling medium, carry out wet primary ball milling in a primary ball mill with a steel ball diameter of 6mm for 4 hours, and then transfer to a secondary ball mill with a steel ball diameter of 4mm for secondary ball milling for 12 hours. The average particle size of the slurry particles after two-stage ball milling is 0.5μm.

[0080] After ball milling, the water content in the obtained slurry is adjusted to a solid content of 70wt%, and the slurry is molded in a 14000Oe magnetic field to obtain a cylinder with a diameter of 43.2mm and a height of 12mm, and the molding pressure is 4MPa; the molded body is heat treated at a temperature of 600°C to completely remove the organic dispersant, and then sintered in an oxygen-rich atmosphere at a heating rate of 150°C / hour, and the sintering temperature is kept at 1210°C for 2h, and then the upper and lower surfaces of the sample are ground to obtain the permanent magnet ferrite material.

[0081] In the permanent magnet ferrite material obtained in this embodiment, the element contents of the pre-sintered material are shown in the following table:

[0082] <![CDATA[Fe2O3]]> SrO CaO <![CDATA[La2O3]]> <![CDATA[Co2O3]]> 84.68 0.477 2.85 7.67 2.47

[0083] Two permanent magnet ferrite materials were prepared by the preparation method described in this embodiment, and the magnetic properties and squareness were tested. The test results are as follows:

[0084] serial number Br(Gs) Hcb(Oe) Hcj(Oe) BHm(MGOe) Sintering temperature(℃) Squareness 1 4190 3913.9 5061.7 4.337 1210 0.8726 2 4152 3819.8 5065.4 4.188 1210 0.8312

[0085] Example 3

[0086] This embodiment provides a permanent magnet ferrite material, and the preparation method of the permanent magnet ferrite material comprises the following steps:

[0087] (1) According to Sr 0.046 Ca 0.492 La 0.461 Fe 10.15 Co 0.279 Weigh the corresponding raw materials, including 485.3g of iron oxide red, 4.2g of strontium carbonate, 29.66g of calcium carbonate, 45g of lanthanum oxide, and 13.7g of cobalt oxide. Add the weighed raw materials into a ball mill, add 840mL of water, mix and stir for 5 hours, and the average particle size of the slurry particles after mixing is 0.5μm;

[0088] The wet mixed granular material is dried and pre-fired in an oxygen-rich atmosphere to obtain a pre-fired material, wherein the pre-fired temperature is 1250° C., the heat preservation time is 1 hour, and the pre-fired method is microwave sintering;

[0089] (2) adding 0.2 wt% of calcium gluconate as an organic dispersant to the pre-sintered particles, and then dry-crushing the pre-sintered particles in a continuous dry vibration ball mill for 5 minutes, wherein the average particle size of the powder after crushing is 5.0 μm;

[0090] Weigh 450g of the crushed material, add 0.45wt% SiO2 powder, 0.1wt% CaCO3 powder, and 0.6wt% SrCO3 powder to the crushed material, then add 680ml of deionized water as the ball milling medium, carry out wet primary ball milling in a primary ball mill with a steel ball diameter of 6mm for 4 hours, and then transfer to a secondary ball mill with a steel ball diameter of 4mm for secondary ball milling for 12 hours. The average particle size of the slurry particles after two-stage ball milling is 0.65μm.

[0091] After ball milling, the water content in the obtained slurry is adjusted to a solid content of 70wt%, and the slurry is molded in a 15000Oe magnetic field to obtain a cylinder with a diameter of 43.2mm and a height of 12mm, and the molding pressure is 4MPa; the molded body is heat treated at a temperature of 300°C to completely remove the organic dispersant, and then sintered in an oxygen-rich atmosphere at a heating rate of 150°C / hour, and the sintering temperature is kept at 1210°C for 1 hour, and then the upper and lower surfaces of the sample are ground to obtain the permanent magnet ferrite material.

[0092] In the permanent magnet ferrite material obtained in this embodiment, the element contents of the pre-sintered material are shown in the following table:

[0093] <![CDATA[Fe2O3]]> SrO CaO <![CDATA[La2O3]]> <![CDATA[Co2O3]]> 84.68 0.477 2.85 7.67 2.47

[0094] Two permanent magnet ferrite materials were prepared by the preparation method described in this embodiment, and the magnetic properties and squareness were tested. The test results are as follows:

[0095]

[0096]

[0097] Example 4

[0098] This embodiment provides a permanent magnet ferrite material. The preparation method of the permanent magnet ferrite material is the same as that of Embodiment 1 except that the content of the SrCO3 powder in step (2) is 0.3 wt%.

[0099] In the permanent magnet ferrite material obtained in this embodiment, the element contents of the pre-sintered material are shown in the following table:

[0100] <![CDATA[Fe2O3]]> SrO CaO <![CDATA[La2O3]]> <![CDATA[Co2O3]]> 85.7 0.483 2.46 7.75 2.48

[0101] Two permanent magnet ferrite materials were prepared by the preparation method described in this embodiment, and the magnetic properties and squareness were tested. The test results are as follows:

[0102]

[0103] Example 5

[0104] This embodiment provides a permanent magnet ferrite material. The preparation method of the permanent magnet ferrite material is the same as that of Embodiment 1 except that the content of the SrCO3 powder in step (2) is 0.8 wt%.

[0105] In the permanent magnet ferrite material obtained in this embodiment, the element contents of the pre-sintered material are shown in the following table:

[0106]

[0107]

[0108] Two permanent magnet ferrite materials were prepared by the preparation method described in this embodiment, and the magnetic properties and squareness were tested. The test results are as follows:

[0109] serial number Br(Gs) Hcb(Oe) Hcj(Oe) BHm(MGOe) Sintering temperature(℃) Squareness 1 4252 3485.2 4099.1 4.337 1210 0.7251 2 4243 3411.6 4017.9 4.329 1210 0.7219

[0110] Example 6

[0111] This embodiment provides a permanent magnet ferrite material. The preparation method of the permanent magnet ferrite material is the same as that of Embodiment 1, except that the pre-sintering in step (1) is performed in a sintering furnace instead of microwave sintering.

[0112] In the permanent magnet ferrite material obtained in this embodiment, the element contents of the pre-sintered material are shown in the following table:

[0113] <![CDATA[Fe2O3]]> SrO CaO <![CDATA[La2O3]]> <![CDATA[Co2O3]]> 85.7 0.483 2.46 7.75 2.48

[0114] Two permanent magnet ferrite materials were prepared by the preparation method described in this embodiment, and the magnetic properties and squareness were tested. The test results are as follows:

[0115]

[0116] Example 7

[0117] The present embodiment provides a permanent magnet ferrite material. The preparation method of the permanent magnet ferrite material is the same as that of Example 1, except for the two-stage ball milling of the pre-sintered material, 0.2wt% of the organic dispersant calcium gluconate as the pre-sintered material, 0.45wt% of SiO2 powder, 0.1wt% of CaCO3 powder and 0.6wt% of SrCO3 powder as the crushed material, and the subsequent steps in step (1).

[0118] In the permanent magnet ferrite material obtained in this embodiment, the element contents of the pre-sintered material are shown in the following table:

[0119] <![CDATA[Fe2O3]]> SrO CaO <![CDATA[La2O3]]> <![CDATA[Co2O3]]> 85.7 0.483 2.46 7.75 2.48

[0120] Two permanent magnet ferrite materials were prepared by the preparation method described in this embodiment, and the magnetic properties and squareness were tested. The test results are as follows:

[0121] serial number Br(Gs) Hcb(Oe) Hcj(Oe) BHm(MGOe) Sintering temperature(℃) Squareness 1 4153 3358.3 4039 4.151 1210 0.7111 2 4101 3344.4 4109 4.192 1210 0.7202

[0122] Comparative Example 1

[0123] This comparative example provides a permanent magnet ferrite material. The preparation method of the permanent magnet ferrite material is the same as that of Example 1 except that SrCO3 powder is not added in step (2).

[0124] In the permanent magnet ferrite material obtained in this comparative example, the element contents of the pre-sintered material are shown in the following table:

[0125] <![CDATA[Fe2O3]]> SrO CaO <![CDATA[La2O3]]> <![CDATA[Co2O3]]> 85.7 0.483 2.46 7.75 2.48

[0126] Two permanent magnet ferrite materials were prepared by the preparation method described in this comparative example, and the magnetic properties and squareness were tested. The test results are as follows:

[0127]

[0128]

[0129] Comparative Example 2

[0130] This comparative example provides a permanent magnet ferrite material. The preparation method of the permanent magnet ferrite material is as follows: 0.11 Ca 0.39 La 0.5 Fe 11.6 Co 0.33 Weigh the corresponding raw materials, including 485.3 g of iron oxide red, 8.72 g of strontium carbonate, 20.57 g of calcium carbonate, 42.71 g of lanthanum oxide, and 14.21 g of cobalt oxide, and carry out step (1). The secondary additives in step (2) are 0.4 wt% of SiO2 powder and 1 wt% of CaCO3 powder in the crushed material, and the rest are the same as in Example 1.

[0131] In the permanent magnet ferrite material obtained in this comparative example, the element contents of the pre-sintered material are shown in the following table:

[0132] <![CDATA[Fe2O3]]> SrO CaO <![CDATA[La2O3]]> <![CDATA[Co2O3]]> 85.79 0.997 2.07 7.44 2.61

[0133] Two permanent magnet ferrite materials were prepared by the preparation method described in this comparative example, and the magnetic properties and squareness were tested. The test results are as follows:

[0134]

[0135] Comparative Example 3

[0136] This comparative example provides a permanent magnet ferrite material. The preparation method of the permanent magnet ferrite material is the same as that of Example 1 except that 0.5 wt % of Fe2O3 powder is added during the secondary feeding in step (2).

[0137] In the permanent magnet ferrite material obtained in this comparative example, the element contents of the pre-sintered material are shown in the following table:

[0138] <![CDATA[Fe2O3]]> SrO CaO <![CDATA[La2O3]]> <![CDATA[Co2O3]]> 85.7 0.483 2.46 7.75 2.48

[0139] Two permanent magnet ferrite materials were prepared by the preparation method described in this comparative example, and the magnetic properties and squareness were tested. The test results are as follows:

[0140]

[0141] Comparative Example 4

[0142] This comparative example provides a permanent magnet ferrite material. The preparation method of the permanent magnet ferrite material is the same as that of Example 1 except that 0.5 wt % of H3BO3 powder is added during the secondary feeding in step (2).

[0143] In the permanent magnet ferrite material obtained in this comparative example, the element contents of the pre-sintered material are shown in the following table:

[0144] <![CDATA[Fe2O3]]> SrO CaO <![CDATA[La2O3]]> <![CDATA[Co2O3]]> 85.7 0.483 2.46 7.75 2.48

[0145] Two permanent magnet ferrite materials were prepared by the preparation method described in this comparative example, and the magnetic properties and squareness were tested. The test results are as follows:

[0146]

[0147]

[0148] The methods and conditions for testing magnetism and squareness in the above embodiments and comparative examples include: maintaining the room temperature at 23 degrees, maintaining the sample at a constant temperature for more than 2 hours, and using a BH tester as the testing instrument.

[0149] From the above table we can see that:

[0150] It can be seen from Example 1 and Comparative Examples 1-4 that the secondary additive of the present invention consists of a Si-containing compound, a Ca-containing compound and a Sr-containing compound. When no additional Sr is added or other substances are added, the permanent magnet ferrite material obtained cannot simultaneously ensure the squareness and magnetic properties; it can be seen from Example 1 and Examples 4-5 that the secondary added Sr-containing compound of the present invention is within a specific content range, which is beneficial to simultaneously ensure the magnetic properties and squareness of the material; it can be seen from Example 1 and Example 6 that the microwave sintering method is preferably used during pre-sintering of the present invention; it can be seen from Example 1 and Example 7 that the dispersant of the present invention is preferably added when the pre-sintered material is crushed, which is beneficial to improving the performance of the material.

[0151] In summary, the present invention provides a permanent magnet ferrite material and a preparation method and application thereof. The permanent magnet ferrite material can significantly improve the squareness of the permanent magnet ferrite material while ensuring the precursor of magnetic properties by adding components of specific composition to the secondary additives, and at the same time reduce the use of high-priced element cobalt while meeting performance requirements.

[0152] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A permanent magnet ferrite material, characterized in that: The permanent magnet ferrite material comprises a main component and a secondary additive, wherein the main component comprises A 1-x R x Fe 2n-y M y O 19 , wherein x is 0.4-0.6, y is 0.2-0.5, n is 5.0-5.8, A includes Ca and Sr in a molar ratio of (0.35-0.55):(0.045-0.15), R includes a rare earth element, and M includes Co; The secondary additive consists of a Si-containing compound, a Ca-containing compound and a Sr-containing compound.

2. The permanent magnet ferrite material according to claim 1, characterized in that: The n is 5.1-5.3; Preferably, the A also includes Ba; Preferably, the R also includes Bi; Preferably, the M further includes any one of Mn, Mg, Ni, Cu or Zn, or a combination of at least two thereof.

3. The permanent magnet ferrite material according to claim 1 or 2, characterized in that: The Si-containing compound is 0.4-0.45wt% of the main component; Preferably, the Ca-containing compound is 0.1-0.5wt% of the main component; Preferably, the Sr-containing compound is 0.5-0.6 wt % of the main component.

4. A method for preparing the permanent magnetic ferrite material according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) mixing and pre-calcining the iron source, A source, R source and M source according to the formula amount of the main components to obtain a pre-calcined material; (2) crushing the pre-sintered material in step (1) to obtain a crushed material, and performing secondary mixing, molding and sintering on the crushed material and the secondary additive to obtain the permanent magnet ferrite material; The secondary additive consists of a silicon source, a calcium source and a strontium source.

5. The preparation method according to claim 4, characterized in that: The pre-sintering method in step (1) includes microwave sintering; Preferably, the pre-burning temperature in step (1) is 1100-1250° C. and the time is 0.5-3 h; Preferably, the average particle size of all raw materials before the one-time mixing in step (1) is no more than 2 μm; Preferably, the primary mixing in step (1) comprises wet mixing; Preferably, the average particle size of the particles obtained by the one-time mixing in step (1) does not exceed 0.8 μm.

6. The preparation method according to claim 4 or 5, characterized in that: The silicon source in step (2) is 0.4-0.45wt% of the crushed material; Preferably, the calcium source in step (2) is 0.1-0.5wt% of the crushed material; Preferably, the strontium source in step (2) is 0.5-0.6wt% of the crushed material; Preferably, the silicon source in step (2) comprises SiO2; Preferably, the calcium source in step (2) comprises CaCO3; Preferably, the strontium source in step (2) comprises SrCO3.

7. The preparation method according to any one of claims 4 to 6, characterized in that: During the crushing in step (2), a dispersant is also added; Preferably, the added amount of the dispersant is 0-1wt% of the pre-sintered material, but excluding 0wt%.

8. The preparation method according to any one of claims 4 to 7, characterized in that: The crushing method in step (2) includes dry crushing to obtain crushed materials with an average particle size of 3-5 μm; Preferably, the secondary mixing in step (2) comprises wet ball milling, wherein the average particle size of the particles is less than 0.75 μm, and preferably the average particle size of the particles is 0.5-0.7 μm; Preferably, the time for the secondary mixing in step (2) is 16-24 hours, preferably 18-20 hours.

9. The preparation method according to any one of claims 4 to 8, characterized in that: The solid content of the mixture obtained by the secondary mixing in step (2) is adjusted to 55-75wt% and then molded; Preferably, the forming in step (2) is carried out in a magnetic field of 14000-15000 Oe; Preferably, after the molding in step (2) and before sintering, heat treatment is also performed; Preferably, the temperature of the heat treatment is 100-600°C; Preferably, the sintering in step (2) is carried out in an oxygen-containing atmosphere; Preferably, the sintering temperature in step (2) is 1150-1250°C; Preferably, the sintering time in step (2) is 0.5-3 h, preferably 0.5-2 h.

10. An application of the permanent magnetic ferrite material according to any one of claims 1 to 3, characterized in that: The applications include use in electrical machinery equipment.

Images