Permanent magnetic ferrite magnetic tile and manufacturing method thereof

Abstract

The invention discloses a permanent magnetic ferrite magnetic tile and a manufacturing method thereof, the permanent magnetic ferrite magnetic tile comprises a main material and an additive, the main material and the additive comprise the following components by weight: 50-70% of strontium ferrite; 20%-35% of barium ferrite; an additive: 1.5%-3% of neodymium oxide; 0.5%-2% of praseodymium oxide; 1%-3% of zirconium oxide; 1%-2% of aluminum oxide; 0.5%-1% of titanium oxide; 0.2%-0.6% of boron oxide; the sum of all the components is 100%. Through ferrite proportion optimization and rare earth doping, the residual magnetism of the permanent magnetic ferrite magnetic shoe can reach 430 mT, the demagnetization capability is larger than or equal to 300 kA / m, the magnetism of the permanent magnetic ferrite magnetic shoe is improved compared with a traditional formula, the magnetic flux attenuation rate at the temperature of 200 DEG C is smaller than or equal to 8% and lower than the average level, the stability of the permanent magnetic ferrite magnetic shoe in the high-temperature environment is higher, and the service life of the permanent magnetic ferrite magnetic shoe is prolonged. The compressive strength of the permanent magnetic ferrite magnetic tile is greater than or equal to 3600N, the crack-free qualification rate is greater than or equal to 98%, the mechanical strength is effectively improved, the permanent magnetic ferrite magnetic tile is not easy to crack due to vibration or impact, the waste adding proportion is improved to 30% in the manufacturing process of the permanent magnetic ferrite magnetic tile, and the raw material cost is reduced by 25%.

Description

Technical Field

[0001] The invention belongs to the technical field of permanent magnet ferrite magnetic tile manufacturing, and in particular relates to a permanent magnet ferrite magnetic tile and a manufacturing method thereof. Background Art

[0002] Anisotropic sintered permanent ferrite tiles are the most widely used and produced permanent magnet material in the world, offering the best price-performance ratio. They are widely used in large applications such as exciters, auxiliary exciters, and aircraft motors, as well as small applications such as floppy and hard drive motors in computers, motors in information products, and high-performance applications such as sensors and magnetic levitation devices. As a key component in DC motors, permanent ferrite tiles place high demands on their magnetic properties.

[0003] The existing permanent magnet ferrite magnetic tiles have the following problems:

[0004] 1. Insufficient high-temperature performance: When the temperature exceeds 150°C, the magnetic flux attenuation rate is ≥20%, which is difficult to meet the requirements of high-temperature scenarios such as electric vehicle motors;

[0005] 2. Low mechanical strength: The compressive strength is generally lower than 3000N, and it is easy to crack due to vibration or impact;

[0006] 3. Insufficient utilization of rare earth elements: The addition amount of rare earth elements (such as Nd and Pr) in traditional formulas is low (<1%), which fails to fully improve the magnetic properties. Summary of the Invention

[0007] The present invention aims to solve the problems in the prior art and proposes the following technical solutions:

[0008] The permanent ferrite magnetic tile includes a main material and additives. The components and weight percentages of the main material and additives are as follows:

[0009] Main ingredients: strontium ferrite 50%-70%;

[0010] Barium ferrite 20%-35%;

[0011] Additives: neodymium oxide 1.5%-3%;

[0012] Praseodymium oxide 0.5%-2%;

[0013] Zirconia 1%-3%;

[0014] Alumina 1%-2%;

[0015] Titanium oxide 0.5%-1%;

[0016] Boron oxide 0.2%-0.6%;

[0017] The sum of the components is 100%.

[0018] A method for manufacturing a permanent ferrite magnetic tile, comprising:

[0019] S1. Raw material pretreatment:

[0020] Strontium carbonate, barium carbonate and iron oxide are mixed in a stoichiometric ratio and pre-fired at 1180°C for 2 hours to generate strontium ferrite and barium ferrite matrices. The pre-fired materials are ground to 0.8μm-1.2μm by jet milling;

[0021] S2. Mixing and granulation:

[0022] Strontium ferrite and barium ferrite matrix are mixed with neodymium oxide, praseodymium oxide, zirconium oxide, aluminum oxide, titanium oxide and boron oxide, and granulated by adding 3% polyvinyl alcohol solution, with the particle size controlled at 100 μm-150 μm;

[0023] S3, magnetic field forming:

[0024] Wet pressing in a vertical magnetic field, holding time 60 seconds, green density ≥ 3.2g / cm 3 ;

[0025] S4 gradient sintering:

[0026] Stage 1: debinding at 600-800°C, stage 2: sintering at 1250°C, stage 3: tempering at 550°C;

[0027] S5. Post-processing:

[0028] The permanent magnet ferrite tiles sintered in S4 are ground by a four-station diamond grinding wheel and magnetized by a pulsed magnetic field.

[0029] As a preferred embodiment of the above technical solution, in S3, the magnetic field strength of the vertical magnetic field is 1200 kA / m, and the pressure of the wet pressing is 40 MPa.

[0030] As a preferred embodiment of the above technical solution, in S4, the heating rate of stage one is 5°C / min and is protected by argon gas, stage two needs to be kept warm for 8 hours, with a vacuum degree of ≤1×10-3Pa, and the cooling rate of stage three is 2°C / min.

[0031] As a preferred embodiment of the above technical solution, in S5, the rotation speed of the four-station diamond grinding wheel is 1500r / min, and the tolerance is ±0.03mm;

[0032] The magnetic field strength of the pulsed magnetic field is 4 T, and the pulse width is 10 ms.

[0033] The beneficial effects of the present invention are:

[0034] 1. The present invention optimizes the ferrite ratio and rare earth doping to make the remanence of the permanent ferrite magnetic tile reach 430mT and the demagnetization capacity ≥300kA / m, so that the magnetic properties of the permanent ferrite magnetic tile are improved compared with the traditional formula;

[0035] 2. The magnetic flux attenuation rate of the present invention is ≤8% at a temperature of 200°C, which is lower than the average level, making the permanent magnet ferrite magnetic tile more stable in high temperature environments;

[0036] 3. The compressive strength of the permanent magnet ferrite magnetic tile of the present invention is ≥3600N, and the crack-free qualified rate is ≥98%. The mechanical strength is effectively improved, making it less likely to crack due to vibration or impact;

[0037] 4. During the production process of the permanent magnet ferrite magnetic tile of the present invention, the proportion of waste material added is increased to 30%, and the raw material cost is reduced by 25%. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0039] Example 1

[0040] The permanent ferrite magnetic tile includes a main material and additives. The components and weight percentages of the main material and additives are as follows:

[0041] Main ingredients: strontium ferrite 50%-70%;

[0042] Barium ferrite 20%-35%;

[0043] Additives: neodymium oxide 1.5%-3%;

[0044] Praseodymium oxide 0.5%-2%;

[0045] Zirconia 1%-3%;

[0046] Alumina 1%-2%;

[0047] Titanium oxide 0.5%-1%;

[0048] Boron oxide 0.2%-0.6%;

[0049] The total of all components is 100%, and the remainder is unavoidable impurities (≤0.1%).

[0050] The method for manufacturing a permanent magnet ferrite tile comprises: S1, raw material pretreatment: mixing strontium carbonate, barium carbonate, and iron oxide in a stoichiometric ratio, pre-calcining at 1180° C. for 2 hours to generate strontium ferrite and barium ferrite matrices, and crushing the pre-calcined material to 0.8 μm-1.2 μm by jet milling;

[0051] S2. Mixing and granulation: mixing strontium ferrite and barium ferrite matrix with neodymium oxide, praseodymium oxide, zirconium oxide, aluminum oxide, titanium oxide and boron oxide, adding 3% polyvinyl alcohol solution to granulate, and controlling the particle size to be 100 μm-150 μm;

[0052] S3, magnetic field molding: wet pressing in a vertical magnetic field, holding time 60 seconds, green density ≥ 3.2g / cm 3 , the magnetic field strength of the vertical magnetic field is 1200 kA / m, and the wet pressing pressure is 40 MPa;

[0053] S4 gradient sintering: Stage 1: 600℃-800℃ debinding, heating rate of 5℃ / min, and argon protection; Stage 2: 1250℃ sintering, holding temperature for 8 hours, with vacuum degree ≤1×10-3Pa; Stage 3: 550℃ tempering, cooling rate of 2℃ / min;

[0054] S5, post-processing: The permanent magnet ferrite tiles sintered in S4 are ground by a four-station diamond grinding wheel (the rotation speed of the four-station diamond grinding wheel is 1500r / min, and the tolerance is ±0.03mm), and magnetized by a pulsed magnetic field (the magnetic field strength of the pulsed magnetic field is 4T, and the pulse width is 10ms).

[0055] Example 2

[0056] The permanent ferrite magnetic tile includes a main material and additives. The components and weight percentages of the main material and additives are as follows:

[0057] Main ingredients: strontium ferrite 68%;

[0058] Barium ferrite 22%;

[0059] Additives: Neodymium oxide 2.5%;

[0060] Praseodymium oxide 1.5%;

[0061] Zirconia 2.5%;

[0062] Alumina 1.8%;

[0063] Titanium oxide 0.6%;

[0064] Boron oxide 0.5%.

[0065] The method for manufacturing a permanent magnet ferrite tile comprises: S1, raw material pretreatment: mixing strontium carbonate, barium carbonate, and iron oxide in a stoichiometric ratio, pre-calcining at 1180° C. for 2 hours to generate strontium ferrite and barium ferrite matrices, and crushing the pre-calcined material to 0.8 μm-1.2 μm by jet milling;

[0066] S2. Mixing and granulation: mixing strontium ferrite and barium ferrite matrix with neodymium oxide, praseodymium oxide, zirconium oxide, aluminum oxide, titanium oxide and boron oxide, adding 3% polyvinyl alcohol solution to granulate, and controlling the particle size to be 100 μm-150 μm;

[0067] S3, magnetic field molding: wet pressing in a vertical magnetic field, holding time 60 seconds, green density ≥ 3.2g / cm 3 , the magnetic field strength of the vertical magnetic field is 1200 kA / m, and the wet pressing pressure is 40 MPa;

[0068] S4 gradient sintering: Stage 1: 600℃-800℃ debinding, heating rate of 5℃ / min, and argon protection; Stage 2: 1250℃ sintering, holding temperature for 8 hours, with vacuum degree ≤1×10-3Pa; Stage 3: 550℃ tempering, cooling rate of 2℃ / min;

[0069] S5, post-processing: The permanent magnet ferrite tiles sintered in S4 are ground by a four-station diamond grinding wheel (the rotation speed of the four-station diamond grinding wheel is 1500r / min, and the tolerance is ±0.03mm), and magnetized by a pulsed magnetic field (the magnetic field strength of the pulsed magnetic field is 4T, and the pulse width is 10ms).

[0070] Example 3

[0071] The permanent ferrite magnetic tile includes a main material and additives. The components and weight percentages of the main material and additives are as follows:

[0072] Main ingredients: strontium ferrite 58%;

[0073] Barium ferrite 30%;

[0074] Additives: neodymium oxide 2.0%;

[0075] Praseodymium oxide 1.0%;

[0076] Zirconia 2.0%;

[0077] Alumina 1.5%;

[0078] Titanium oxide 0.7%;

[0079] Boron oxide 0.4%.

[0080] The method for manufacturing a permanent magnet ferrite tile comprises: S1, raw material pretreatment: mixing strontium carbonate, barium carbonate, and iron oxide in a stoichiometric ratio, pre-calcining at 1180° C. for 2 hours to generate strontium ferrite and barium ferrite matrices, and crushing the pre-calcined material to 0.8 μm-1.2 μm by jet milling;

[0081] S2. Mixing and granulation: mixing strontium ferrite and barium ferrite matrix with neodymium oxide, praseodymium oxide, zirconium oxide, aluminum oxide, titanium oxide and boron oxide, adding 3% polyvinyl alcohol solution to granulate, and controlling the particle size to be 100 μm-150 μm;

[0082] S3, magnetic field molding: wet pressing in a vertical magnetic field, holding time 60 seconds, green density ≥ 3.2g / cm 3 , the magnetic field strength of the vertical magnetic field is 1200 kA / m, and the wet pressing pressure is 40 MPa;

[0083] S4 gradient sintering: Stage 1: 600℃-800℃ debinding, heating rate of 5℃ / min, and argon protection; Stage 2: 1250℃ sintering, holding temperature for 8 hours, with vacuum degree ≤1×10-3Pa; Stage 3: 550℃ tempering, cooling rate of 2℃ / min;

[0084] S5, post-processing: The permanent magnet ferrite tiles sintered in S4 are ground by a four-station diamond grinding wheel (the rotation speed of the four-station diamond grinding wheel is 1500r / min, and the tolerance is ±0.03mm), and magnetized by a pulsed magnetic field (the magnetic field strength of the pulsed magnetic field is 4T, and the pulse width is 10ms).

[0085] Example 4

[0086] The permanent ferrite magnetic tile includes a main material and additives. The components and weight percentages of the main material and additives are as follows:

[0087] Main ingredients: strontium ferrite 52%;

[0088] Barium ferrite 34%;

[0089] Additives: neodymium oxide 1.6%;

[0090] Praseodymium oxide 0.8%;

[0091] Zirconia 1.2%;

[0092] Alumina 1.2%;

[0093] Titanium oxide 0.9%;

[0094] Boron oxide 0.3%.

[0095] The method for manufacturing a permanent magnet ferrite tile comprises: S1, raw material pretreatment: mixing strontium carbonate, barium carbonate, and iron oxide in a stoichiometric ratio, pre-calcining at 1180° C. for 2 hours to generate strontium ferrite and barium ferrite matrices, and crushing the pre-calcined material to 0.8 μm-1.2 μm by jet milling;

[0096] S2. Mixing and granulation: mixing strontium ferrite and barium ferrite matrix with neodymium oxide, praseodymium oxide, zirconium oxide, aluminum oxide, titanium oxide and boron oxide, adding 3% polyvinyl alcohol solution to granulate, and controlling the particle size to be 100 μm-150 μm;

[0097] S3, magnetic field molding: wet pressing in a vertical magnetic field, holding time 60 seconds, green density ≥ 3.2g / cm 3 , the magnetic field strength of the vertical magnetic field is 1200 kA / m, and the wet pressing pressure is 40 MPa;

[0098] S4 gradient sintering: Stage 1: 600℃-800℃ debinding, heating rate of 5℃ / min, and argon protection; Stage 2: 1250℃ sintering, holding temperature for 8 hours, with vacuum degree ≤1×10-3Pa; Stage 3: 550℃ tempering, cooling rate of 2℃ / min;

[0099] S5, post-processing: The permanent magnet ferrite tiles sintered in S4 are ground by a four-station diamond grinding wheel (the rotation speed of the four-station diamond grinding wheel is 1500r / min, and the tolerance is ±0.03mm), and magnetized by a pulsed magnetic field (the magnetic field strength of the pulsed magnetic field is 4T, and the pulse width is 10ms).

[0100] The following table shows the corresponding data of the permanent magnet ferrite tiles obtained in Examples 2-4 above:

[0101]

[0102] In summary, the ratio of strontium ferrite ↑→Br / Hcj↑, but the temperature resistance decreases;

[0103] Barium ferrite ratio ↑ → high temperature stability ↑, magnetic properties ↓;

[0104] The ratio of zirconia to alumina increases → mechanical strength increases and grain size becomes finer.

[0105] Example 2 is suitable for high-precision servo motors (requiring a strong magnetic field), Example 3 is suitable for new energy vehicle drive motors (balanced performance), and Example 4 is suitable for industrial high-temperature motors (long-term temperature resistance requirements).

[0106] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same.

Claims

1. Permanent ferrite magnetic tiles, including main materials and additives, characterized by: The components and weight percentages of the main ingredients and additives are as follows: Main ingredients: strontium ferrite 50%-70%; Barium ferrite 20%-35%; Additives: neodymium oxide 1.5%-3%; Praseodymium oxide 0.5%-2%; Zirconia 1%-3%; Alumina 1%-2%; Titanium oxide 0.5%-1%; Boron oxide 0.2%-0.6%; The total of the components is 100%.

2. A method for manufacturing a permanent magnet ferrite magnetic tile according to claim 1, characterized in that: include, S1. Raw material pretreatment: Strontium carbonate, barium carbonate and iron oxide are mixed in a stoichiometric ratio and pre-fired at 1180°C for 2 hours to generate strontium ferrite and barium ferrite matrices. The pre-fired materials are ground to 0.8μm-1.2μm by jet milling; S2. Mixing and granulation: Strontium ferrite and barium ferrite matrix are mixed with neodymium oxide, praseodymium oxide, zirconium oxide, aluminum oxide, titanium oxide and boron oxide, and granulated by adding 3% polyvinyl alcohol solution, with the particle size controlled at 100 μm-150 μm; S3, magnetic field forming: Wet pressing in a vertical magnetic field, holding time 60 seconds, green density ≥ 3.2g / cm 3 ; S4 gradient sintering: Stage 1: debinding at 600-800°C, stage 2: sintering at 1250°C, stage 3: tempering at 550°C; S5. Post-processing: The permanent magnet ferrite tiles sintered in S4 are ground by a four-station diamond grinding wheel and magnetized by a pulsed magnetic field.

3. The method for manufacturing a permanent magnet ferrite magnetic tile according to claim 2, wherein: In S3, the magnetic field strength of the perpendicular magnetic field is 1200 kA / m, and the pressure of the wet pressing is 40 MPa.

4. The method for manufacturing a permanent magnet ferrite magnetic tile according to claim 2, wherein: In S4, the heating rate of stage 1 is 5°C / min and is protected by argon. Stage 2 needs to be kept warm for 8 hours, with a vacuum degree of ≤1×10-3Pa. The cooling rate of stage 3 is 2°C / min.

5. The method for manufacturing a permanent magnet ferrite magnetic tile according to claim 2, wherein: In S5, the speed of the four-station diamond grinding wheel is 1500 r / min, with a tolerance of ±0.03 mm; The magnetic field strength of the pulsed magnetic field is 4 T, and the pulse width is 10 ms.

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