Preparation process of low-loss manganese zinc ferrite magnetic core

Abstract

The invention provides a preparation process of a low-loss manganese-zinc ferrite magnetic core, belongs to the technical field of soft magnetic ferrites, and solves the technical problem of lack of an electronic material with high magnetic conductivity at high frequency in the prior art. A preparation process of a low-loss manganese-zinc ferrite magnetic core comprises the following steps: taking the following components in parts by weight: 10-15 parts of manganous-manganic oxide, 62-79 parts of ferric oxide and 13-17 parts of zinc oxide, adding the components into a double-screw mixer, uniformly mixing, and adding auxiliary components in the mixing process, the auxiliary component comprises at least one of V2O5, Ca2O3, Nb2O5, TiO2 and SnO2, and the mixed raw materials are subjected to ultrasonic dispersion after mixing is completed. The material has the advantage of high magnetic conductivity under high frequency.

Description

Technical Field

[0001] The invention belongs to the technical field of soft ferrites, and relates to a preparation process of a manganese-zinc ferrite core, in particular to a preparation process of a low-loss manganese-zinc ferrite core. Background Art

[0002] Manganese-zinc ferrite is actually a single-phase solid solution, which is composed of spinel-structured manganese ferrite, zinc ferrite, and a small amount of ferroferric oxide. Manganese-zinc ferrite materials can be used to make solenoid valves, magnetic heads, switches, magnetic fluids, and can also be used in magnetic recording media, magnetic resonance imaging, magnetic carriers of recording materials and drugs, catalysts and other devices. It is very widely used. Ferrite is the most important material in soft ferrite materials. Its output is very large, almost accounting for more than the total production of soft ferrite materials.

[0003] In the era of information technology, with the rapid development of communication satellites and mobile communication applications, the impact of electromagnetic interference (EMI) in the military and civilian electronic information fields has become increasingly serious, causing great harm to the public environment, personal safety and information confidentiality. An effective way to solve electromagnetic pollution and improve the ability of electronic equipment to resist electromagnetic interference is to adopt electromagnetic compatibility (EMC) design, which requires a large amount of anti-electromagnetic interference materials. With the miniaturization and high-frequency development of electronic equipment, there is an urgent need for electronic materials with high magnetic permeability at high frequencies. Summary of the invention

[0004] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose a preparation process for a low-loss manganese-zinc ferrite core. The technical problem to be solved by the invention is: how to achieve high magnetic permeability at high frequencies.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A preparation process of a low-loss manganese-zinc ferrite core comprises the following steps:

[0007] S1 Ingredients Mixing:

[0008] The following ingredients are composed by weight: 10-15 parts of manganese tetraoxide, 62-79 parts of ferric oxide, and 13-17 parts of zinc oxide, which are added into a twin-screw mixer and mixed evenly, and auxiliary ingredients are added during the mixing process, and the auxiliary ingredients include at least one selected from V2O5, Ca2O3, Nb2O5, TiO2, and SnO2. After mixing, the mixed raw materials are ultrasonically dispersed.

[0009] S2 raw material granulation:

[0010] The mixed raw materials are sand-milled once by a high-pressure micro-powder mill to obtain a mixed slurry with a particle size of 0.5 to 1.0 um. The mixed slurry is sent into a silo of a granulator, and the mixed slurry is granulated into particles by the granulator.

[0011] S3 Granule Drying:

[0012] The granular raw materials are sent into a dryer to be dried, and then the dried granular raw materials are quickly cold pressed. After the cold pressing is completed, the granular raw materials are placed in a sintering furnace for pre-sintering.

[0013] S4 uniform crushing:

[0014] The pre-sintered granular raw materials are sent to a crusher for crushing to obtain pre-sintered granules with a particle size of 0.1 to 0.4 mm.

[0015] S5 sintering molding:

[0016] The pre-sintered particles are poured into the mold in batches, and the filled mold is placed in a sintering furnace. The pre-sintered particles in the mold are completely sintered by the sintering furnace. After sintering, the mold is taken out for rapid cooling. After the mold and the internal magnetic core are cooled to room temperature, the magnetic core is taken out.

[0017] In step S5, debris remaining in the mold is cleaned before and after sintering to reduce the defective rate, and the particles filled in the mold are compacted by a cold press and then sintered to reduce the gaps between the particles and reduce the bubbles retained inside after molding.

[0018] The specific sintering steps are: after heating to 1100-1200° C., keeping the temperature for 3-4 hours in a vacuum environment, then restoring the normal oxygen concentration and cooling to 500-700° C., keeping the temperature for 2-3 hours, and finally cooling to room temperature to obtain a manganese-zinc ferrite core.

[0019] In the step S1, the ultrasonic dispersion is performed for 5 min to 10 min.

[0020] The specific steps of pre-sintering in step S3 are: after heating to 750-880° C., pre-sintering for 40-60 minutes.

[0021] The pre-sintering pressure in step S3 is 50-60 MPa.

[0022] The equipment used in the steps S1-S5 is a magnetic core preparation equipment, which includes an ultrasonic disperser and a dryer. The ultrasonic disperser includes a body, a processing chamber opened in the body, and a cover hinged on the body. A mounting seat is slidably arranged in the processing chamber, a processing liner is placed on the mounting seat, a fixing component fixedly matched with the processing liner is arranged in the mounting seat, and a regulating component for controlling the mounting seat to slide up and down is arranged in the body. An ultrasonic generator and a transducer are fixed in the cover, the transducer is electrically connected to the ultrasonic generator, and a variable amplitude rod is fixed on the transducer, the bottom end of the variable amplitude rod is connected to the processing chamber, and an ultrasonic probe is fixed to the bottom end of the variable amplitude rod.

[0023] By adopting the above structure, the particles can be evenly dispersed and mixed through the ultrasonic disperser to further improve the mixing effect, and the fixing component can quickly complete the fixation of the processing liner, making it convenient to fill and remove the particles. The control component can also control the contact between the processing liner and the ultrasonic probe on the amplitude transformer to improve the overall mixing efficiency.

[0024] The fixing assembly includes a pair of clamping arms slidably connected on the mounting seat, and a bidirectional lead screw rotatably connected in the mounting seat. The threaded sections on both sides of the bidirectional lead screw are threadedly connected to the corresponding clamping arms, and a servo motor 1 is fixed in the mounting seat, a driving gear is coaxially fixed to the output end of the servo motor 1, and a transmission gear is coaxially fixed on the bidirectional lead screw, and the driving gear is meshed with the transmission gear.

[0025] With the above structure, the servo motor can drive the driving gear to rotate, and the driving gear can further drive the transmission gear to rotate, and the transmission gear can drive the bidirectional lead screw to rotate. After the bidirectional lead screw rotates, it can drive the two clamping arms to quickly fix the inner tank, thereby improving the overall efficiency and effect.

[0026] The control component includes a control motor fixed in the machine body, a plurality of control screws rotatably connected in the machine body, each of the control screws is threadedly connected to a mounting seat, and the bottom end of each control screw is coaxially fixedly connected to a control gear, a toothed disc is rotatably connected in the machine body, the toothed disc is meshed with each control gear, and the output shaft of the control motor is coaxially fixedly connected to the toothed disc.

[0027] By adopting the above structure, the toothed disc can be driven to rotate by the regulating motor. When the toothed disc rotates, it will drive each regulating gear to rotate. When each regulating gear rotates, it will drive the corresponding regulating screw to rotate, thereby realizing the up and down movement of the mounting plate, achieving rapid contact between the processing liner and the ultrasonic probe, and improving the overall processing efficiency.

[0028] The dryer comprises a tank body and a heating liner rotatably arranged in the tank body, a plurality of flipping strips are spirally fixed in the heating liner, and a limiting groove is provided in the tank body, a limiting ring is coaxially fixed on the surface of the heating liner, the bottom surface of the limiting ring fits the bottom of the limiting groove, a tank cover is hingedly connected to the top of the tank body, a dust collector is fixed on the tank cover, and an input end of the dust collector is connected to the heating liner, a heating element is fixed in the tank body, a driving motor is fixed at the bottom of the tank body, the output shaft of the driving motor is in a cross shape, and a movable groove is provided in the tank body, a bumping cylinder is connected in the movable groove for sliding up and down, a driving shaft is rotatably connected in the bumping cylinder, a compression spring is fixed between the top of the bumping cylinder and the bottom of the movable groove, the top of the driving shaft is coaxially fixedly connected to the heating liner, and a cross groove is provided on the bottom surface of the driving shaft, the cross groove is plugged and matched with the output shaft of the driving motor, a pair of semicircular blocks 1 are fixed to the bumping cylinder, and a pair of semicircular blocks 2 are fixed in the movable groove, and the circular surfaces of the two semicircular blocks 2 are collided and matched with the circular surface of the semicircular block 1.

[0029] By adopting the above structure, the material can be heated and dried by the heating inner tank, and the heating inner tank can rotate, so that the material is constantly turned over in the heating inner tank, thereby improving the drying efficiency, and the fine dust generated during the turning over is sucked out by the dust collector to improve the purity of the material. Then, through the rotation of the bumping cylinder, the semicircular block two continuously collides with the semicircular block one, so that the bumping cylinder is continuously lifted, thereby realizing the ability of reciprocating bumping, so that the heating inner tank can not only turn the material over, but also further increase the friction between the materials through this bumping, and improve the uniform heating of the materials, thereby improving the drying effect.

[0030] Compared with the prior art, the preparation process of the low-loss manganese-zinc ferrite core has the following advantages:

[0031] 1. The preparation process of the low-loss manganese-zinc ferrite core of the present invention is as follows: the mixed raw materials are ground once to improve the fineness of the material, and the components can be further fused during the grinding process, and the ground slurry is formed into particles, and the particles are cold-pressed to improve the material stress and the diffusion degree of the internal components, facilitate transportation and subsequent pre-sintering, form a good diffusion effect between the raw materials, make the components uniform, and then crush after sintering to make the mixing more uniform, promote the formation of a homogeneous phase during the heat treatment process, and help reduce the loss during use.

[0032] 2. The magnetic core preparation equipment of the present invention is adopted: the material is heated and dried by the heating inner tank, and the heating inner tank can rotate, so that the material is constantly turned over in the heating inner tank, thereby improving the drying efficiency, and the fine dust generated during the turning over is sucked out by the dust collector, thereby improving the purity rate of the material, and the semicircular block 2 is constantly collided with the semicircular block 1 by the rotation of the bumping cylinder, so that the bumping cylinder is constantly lifted, thereby realizing the ability of reciprocating bumping, so that the heating inner tank can not only turn the material over, but also further increase the friction between the materials through such bumping, and improve the uniformity of heating of the materials, thereby improving the drying effect.

[0033] 3. The magnetic core preparation equipment of the present invention is adopted: a servo motor drives the driving gear to rotate, the driving gear further drives the transmission gear to rotate, the transmission gear drives the bidirectional lead screw to rotate, and after the bidirectional lead screw rotates, it drives two clamping arms to quickly fix the processing liner, thereby improving the overall efficiency and effect, and making it convenient and quick to fill and take out the particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a comparison table of initial magnetic permeability in the present invention.

[0035] Figure 2 It is a work flow chart of the present invention.

[0036] Figure 3 It is a structural schematic diagram of the magnetic core preparation equipment in the present invention.

[0037] Figure 4 It is a schematic diagram of the structure of the ultrasonic disperser in the present invention when viewed from above.

[0038] Figure 5 It is a schematic diagram of the structure of the control component in the present invention.

[0039] Figure 6 It is a structural schematic diagram of the fixing component in the present invention.

[0040] Figure 7 It is a schematic diagram of the structure inside the drying machine of the present invention.

[0041] Figure 8 It is a structural schematic diagram of the operation of the bump cylinder in the present invention.

[0042] Fig. 9 It is a schematic diagram of the plug-in structure of the drive shaft and the drive motor in the present invention.

[0043] Fig.10 It is a schematic diagram of the structure inside the heating liner of the present invention.

[0044] In the figure, 1. ultrasonic disperser; 2. dryer; 3. machine body; 4. processing chamber; 5. machine cover; 6. mounting seat; 7. processing liner; 8. ultrasonic generator; 9. transducer; 10. amplitude rod; 11. ultrasonic probe; 12. clamping arm; 13. bidirectional screw; 14. servo motor 1; 15. driving gear; 16. transmission gear; 17. tank body; 18. heating liner; 19. flip bar; 20. limit groove; 21. limit ring; 22. tank cover; 23. vacuum cleaner; 24. driving motor; 25. movable groove; 26. bump cylinder; 27. driving shaft; 28. compression spring; 29. ​​cross groove; 30. semicircular block 1; 31. semicircular block 2; 32. regulating motor; 33. regulating screw; 34. regulating gear; 35. geared disc. DETAILED DESCRIPTION

[0045] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0046] Embodiment 1

[0047] A preparation process of a low-loss manganese-zinc ferrite core comprises the following steps:

[0048] S1 Ingredients Mixing:

[0049] The following ingredients are composed by weight: 13 parts of manganese tetraoxide, 65 parts of ferric oxide, and 14 parts of zinc oxide, which are added into a twin-screw mixer for uniform mixing, and auxiliary ingredients are added during the mixing process, and the auxiliary ingredients include at least one selected from V2O5, Ca2O3, Nb2O5, TiO2, and SnO2. After mixing, the mixed raw materials are ultrasonically dispersed.

[0050] S2 raw material granulation:

[0051] The mixed raw materials are sand-milled once by a high-pressure micro-powder mill to obtain a mixed slurry with a particle size of 0.7 um. The mixed slurry is sent into a silo of a granulator, and the mixed slurry is granulated into particles by the granulator.

[0052] S3 Granule Drying:

[0053] The granular raw materials are sent into a dryer to be dried, and then the dried granular raw materials are quickly cold pressed. After the cold pressing is completed, the granular raw materials are placed in a sintering furnace for pre-sintering.

[0054] S4 uniform crushing:

[0055] The pre-sintered granular raw materials are sent to a crusher for crushing to obtain pre-sintered granules with a particle size of 0.2 mm.

[0056] S5 sintering molding:

[0057] The pre-sintered particles are poured into the mold in batches, and the filled mold is placed in a sintering furnace. The pre-sintered particles in the mold are completely sintered by the sintering furnace. After sintering, the mold is taken out for rapid cooling. After the mold and the internal magnetic core are cooled to room temperature, the magnetic core is taken out.

[0058] In step S5, before and after sintering, the debris remaining in the mold is cleaned to reduce the defective rate, and the particles filled in the mold are compacted by a cold press and then sintered to reduce the gap between the particles and reduce the bubbles retained inside after molding.

[0059] The specific sintering steps are: after heating to 1150°C, keep it warm for 3.5 hours in a vacuum environment, then restore the normal oxygen concentration and cool it to 600°C, keep it warm for 2.5 hours, and finally cool it to room temperature to obtain a manganese-zinc ferrite core.

[0060] In step S1, the ultrasonic dispersion is performed for 7 minutes.

[0061] The specific steps of pre-sintering in step S3 are: after heating to 810° C., pre-sintering for 50 minutes.

[0062] The pre-sintering pressure in step S3 is 55 MPa.

[0063] The equipment used in this embodiment are all molding equipment that can be purchased on the current market.

[0064] Embodiment 2

[0065] A preparation process of a low-loss manganese-zinc ferrite core comprises the following steps:

[0066] S1 Ingredients Mixing:

[0067] The following ingredients are composed by weight: 13 parts of manganese tetraoxide, 65 parts of ferric oxide, and 14 parts of zinc oxide, which are added into a twin-screw mixer for uniform mixing, and auxiliary ingredients are added during the mixing process, and the auxiliary ingredients include at least one selected from V2O5, Ca2O3, Nb2O5, TiO2, and SnO2. After mixing, the mixed raw materials are ultrasonically dispersed.

[0068] S2 raw material granulation:

[0069] The mixed raw materials are sand-milled once by a high-pressure micro-powder mill to obtain a mixed slurry with a particle size of 0.7 um. The mixed slurry is sent into a silo of a granulator, and the mixed slurry is granulated into particles by the granulator.

[0070] S3 Granule Drying:

[0071] The granular raw materials are sent into a dryer to be dried, and then the dried granular raw materials are quickly cold pressed. After the cold pressing is completed, the granular raw materials are placed in a sintering furnace for pre-sintering.

[0072] S4 uniform crushing:

[0073] The pre-sintered granular raw materials are sent to a crusher for crushing to obtain pre-sintered granules with a particle size of 0.2 mm.

[0074] S5 sintering molding:

[0075] The pre-sintered particles are poured into the mold in batches, and the filled mold is placed in a sintering furnace. The pre-sintered particles in the mold are completely sintered by the sintering furnace. After sintering, the mold is taken out for rapid cooling. After the mold and the internal magnetic core are cooled to room temperature, the magnetic core is taken out.

[0076] In step S5, before and after sintering, the debris remaining in the mold is cleaned to reduce the defective rate, and the particles filled in the mold are compacted by a cold press and then sintered to reduce the gap between the particles and reduce the bubbles retained inside after molding.

[0077] The specific sintering steps are: after heating to 1150°C, keep it warm for 3.5 hours in a vacuum environment, then restore the normal oxygen concentration and cool it to 600°C, keep it warm for 2.5 hours, and finally cool it to room temperature to obtain a manganese-zinc ferrite core.

[0078] In step S1, the ultrasonic dispersion is performed for 7 minutes.

[0079] The specific steps of pre-sintering in step S3 are: after heating to 810° C., pre-sintering for 50 minutes.

[0080] The equipment used in steps S1-S5 is a magnetic core preparation equipment, an ultrasonic disperser and a dryer for the magnetic core preparation equipment, the ultrasonic disperser includes a body, a processing chamber opened in the body, and a cover hinged on the body, a mounting seat is slidably arranged in the processing chamber, a processing liner is placed on the mounting seat, a fixing component is arranged in the mounting seat for fixing with the processing liner, and a regulating component is arranged in the body for controlling the mounting seat to slide up and down, an ultrasonic generator and a transducer are fixed in the cover, the transducer is electrically connected to the ultrasonic generator, and a variable amplitude rod is fixed on the transducer, the bottom end of the variable amplitude rod is connected to the processing chamber, and an ultrasonic probe is fixed to the bottom end of the variable amplitude rod.

[0081] By adopting the above structure, the particles can be evenly dispersed and mixed through the ultrasonic disperser to further improve the mixing effect, and the fixing component can quickly complete the fixation of the processing liner, making it convenient to fill and remove the particles. The control component can also control the contact between the processing liner and the ultrasonic probe on the amplitude transformer to improve the overall mixing efficiency.

[0082] The fixing assembly includes a pair of clamping arms slidably connected to the mounting seat, and a bidirectional lead screw rotatably connected inside the mounting seat. The threaded sections on both sides of the bidirectional lead screw are threadedly connected to the corresponding clamping arms, and a servo motor 1 is fixed inside the mounting seat. A driving gear is coaxially fixed to the output end of the servo motor 1, and a transmission gear is coaxially fixed on the bidirectional lead screw, and the driving gear is meshed with the transmission gear.

[0083] With the above structure, the servo motor can drive the driving gear to rotate, and the driving gear can further drive the transmission gear to rotate, and the transmission gear can drive the bidirectional lead screw to rotate. After the bidirectional lead screw rotates, it can drive the two clamping arms to quickly fix the inner tank, thereby improving the overall efficiency and effect.

[0084] The control component includes a control motor fixed in the body, multiple control screws rotatably connected in the body, each control screw is threadedly connected to the mounting seat, and the bottom end of each control screw is coaxially fixedly connected with a control gear, a gear plate is rotatably connected in the body, the gear plate is meshed with each control gear, and the output shaft of the control motor is coaxially fixedly connected with the gear plate.

[0085] By adopting the above structure, the toothed disc can be driven to rotate by the regulating motor. When the toothed disc rotates, it will drive each regulating gear to rotate. When each regulating gear rotates, it will drive the corresponding regulating screw to rotate, thereby realizing the up and down movement of the mounting plate, achieving rapid contact between the processing liner and the ultrasonic probe, and improving the overall processing efficiency.

[0086] The dryer comprises a tank body and a heating liner rotatably arranged in the tank body, a plurality of flipping strips are spirally fixed in the heating liner, and a limiting groove is provided in the tank body, a limiting ring is coaxially fixed on the surface of the heating liner, the bottom surface of the limiting ring fits the bottom of the limiting groove, a tank cover is hingedly connected to the top of the tank body, a dust collector is fixed on the tank cover, and an input end of the dust collector is connected to the heating liner, a heating element is fixed in the tank body, a driving motor is fixed at the bottom of the tank body, the output shaft of the driving motor is cross-shaped, and a movable groove is provided in the tank body, a bumping cylinder is connected in the movable groove for sliding up and down, a driving shaft is rotatably connected in the bumping cylinder, a compression spring is fixed between the top of the bumping cylinder and the bottom of the movable groove, the top of the driving shaft is coaxially fixedly connected to the heating liner, and a cross groove is provided on the bottom surface of the driving shaft, the cross groove is plugged and matched with the output shaft of the driving motor, a pair of semicircular blocks 1 are fixed to the bumping cylinder, and a pair of semicircular blocks 2 are fixed in the movable groove, and the circular surfaces of the two semicircular blocks 2 are collided and matched with the circular surface of the semicircular block 1.

[0087] By adopting the above structure, the material can be heated and dried by the heating inner tank, and the heating inner tank can rotate, so that the material is constantly turned over in the heating inner tank, thereby improving the drying efficiency, and the fine dust generated during the turning over is sucked out by the dust collector to improve the purity of the material. Then, through the rotation of the bumping cylinder, the semicircular block two continuously collides with the semicircular block one, so that the bumping cylinder is continuously lifted, thereby realizing the ability of reciprocating bumping, so that the heating inner tank can not only turn the material over, but also further increase the friction between the materials through this bumping, and improve the uniform heating of the materials, thereby improving the drying effect.

[0088] Embodiment 3

[0089] A preparation process of a low-loss manganese-zinc ferrite core comprises the following steps:

[0090] S1 Ingredients Mixing:

[0091] The following ingredients are composed by weight: 10 parts of manganese tetraoxide, 62 parts of ferric oxide, and 13 parts of zinc oxide, which are added into a twin-screw mixer and mixed evenly, and auxiliary ingredients are added during the mixing process, and the auxiliary ingredients include at least one selected from V2O5, Ca2O3, Nb2O5, TiO2, and SnO2. After mixing, the mixed raw materials are ultrasonically dispersed.

[0092] S2 raw material granulation:

[0093] The mixed raw materials are sand-milled once by a high-pressure micro-powder mill to obtain a mixed slurry with a particle size of 0.5 um. The mixed slurry is sent into a silo of a granulator, and the mixed slurry is granulated into particles by the granulator.

[0094] S3 Granule Drying:

[0095] The granular raw materials are sent into a dryer to be dried, and then the dried granular raw materials are quickly cold pressed. After the cold pressing is completed, the granular raw materials are placed in a sintering furnace for pre-sintering.

[0096] S4 uniform crushing:

[0097] The pre-sintered granular raw materials are sent to a crusher for crushing to obtain pre-sintered granules with a particle size of 0.1 mm.

[0098] S5 sintering molding:

[0099] The pre-sintered particles are poured into the mold in batches, and the filled mold is placed in a sintering furnace. The pre-sintered particles in the mold are completely sintered by the sintering furnace. After sintering, the mold is taken out for rapid cooling. After the mold and the internal magnetic core are cooled to room temperature, the magnetic core is taken out.

[0100] In step S5, before and after sintering, the debris remaining in the mold is cleaned to reduce the defective rate, and the particles filled in the mold are compacted by a cold press and then sintered to reduce the gap between the particles and reduce the bubbles retained inside after molding.

[0101] The specific sintering steps are: after heating to 1100°C, keep it warm for 3 hours in a vacuum environment, then restore the normal oxygen concentration and cool it to 500°C, keep it warm for 2 hours, and finally cool it to room temperature to obtain a manganese-zinc ferrite core.

[0102] In step S1, the ultrasonic dispersion is performed for 5 minutes.

[0103] The specific steps of pre-sintering in step S3 are: after heating to 750° C., pre-sintering for 40 minutes.

[0104] The pre-sintering pressure in step S3 is 50 MPa.

[0105] The equipment used in this embodiment is the same as that used in the second embodiment, except that the process conditions are different.

[0106] Embodiment 4

[0107] A preparation process of a low-loss manganese-zinc ferrite core comprises the following steps:

[0108] S1 Ingredients Mixing:

[0109] The following ingredients are composed by weight: 15 parts of manganese tetraoxide, 79 parts of ferric oxide, and 17 parts of zinc oxide, which are added into a twin-screw mixer for uniform mixing, and auxiliary ingredients are added during the mixing process, and the auxiliary ingredients include at least one selected from V2O5, Ca2O3, Nb2O5, TiO2, and SnO2. After mixing, the mixed raw materials are ultrasonically dispersed.

[0110] S2 raw material granulation:

[0111] The mixed raw materials are sand-milled once by a high-pressure micro-powder mill to obtain a mixed slurry with a particle size of 1.0 um. The mixed slurry is sent into a silo of a granulator, and the mixed slurry is granulated into particles by the granulator.

[0112] S3 Granule Drying:

[0113] The granular raw materials are sent into a dryer to be dried, and then the dried granular raw materials are quickly cold pressed. After the cold pressing is completed, the granular raw materials are placed in a sintering furnace for pre-sintering.

[0114] S4 uniform crushing:

[0115] The pre-sintered granular raw materials are sent to a crusher for crushing to obtain pre-sintered granules with a particle size of 0.4 mm.

[0116] S5 sintering molding:

[0117] The pre-sintered particles are poured into the mold in batches, and the filled mold is placed in a sintering furnace. The pre-sintered particles in the mold are completely sintered by the sintering furnace. After sintering, the mold is taken out for rapid cooling. After the mold and the internal magnetic core are cooled to room temperature, the magnetic core is taken out.

[0118] In step S5, before and after sintering, the debris remaining in the mold is cleaned to reduce the defective rate, and the particles filled in the mold are compacted by a cold press and then sintered to reduce the gap between the particles and reduce the bubbles retained inside after molding.

[0119] The specific sintering steps are: after heating to 1200°C, keep it warm for 4 hours in a vacuum environment, then restore the normal oxygen concentration and cool it to 700°C, keep it warm for 3 hours, and finally cool it to room temperature to obtain a manganese-zinc ferrite core.

[0120] In step S1, the ultrasonic dispersion is performed for 10 minutes.

[0121] The specific steps of pre-sintering in step S3 are: after heating to 880° C., pre-sintering for 60 minutes.

[0122] The pre-sintering pressure in step S3 is 60 MPa.

[0123] The equipment used in this embodiment is the same as that used in the second embodiment, except that the process conditions are different.

[0124] Experimental example

[0125] Take 20 sample magnetic cores prepared in Examples 1-4 and 20 existing products, and use a BH hysteresis loop instrument to detect the magnetic permeability of the materials in the temperature range of -60°C to 120°C. The results are shown in Table 1.

[0126] Table 1 Initial magnetic permeability:

[0127]

[0128] It can be seen from Table 1 that when the temperature rises from -60°C to 0°C, the initial magnetic permeability of the material in the embodiment rises by 30% to 47%, and the initial magnetic permeability of the material in the existing product rises by more than 76%. When the temperature gradually rises, compared with the existing product, the initial magnetic permeability of the material obtained in Examples 1-4 increases, but the value is relatively stable, the fluctuation is not large, and the temperature stability is good.

[0129] In Example 1 and Example 2, only the preparation equipment of S1 to S5 is different. The initial magnetic permeability value fluctuation of the sample magnetic core in Example 2 is significantly stronger than that in Example 1. Therefore, using the magnetic core preparation equipment in the present invention can improve the stability of the initial magnetic permeability value fluctuation of the sample magnetic core.

[0130] Compared with Example 2, Example 3 and Example 4 only have different processing conditions, and the equipment used in the processing steps are the same. The initial magnetic permeability value fluctuations of the sample magnetic cores of Example 3 and Example 4 are weaker than that of Example 2. It can be seen that different processing conditions will also affect the initial magnetic permeability value fluctuations of the sample magnetic cores.

[0131] In summary, the initial magnetic permeability stability of the magnetic core produced by the low-loss manganese-zinc ferrite magnetic core preparation process is better than that of the magnetic core product produced by the manganese-zinc ferrite magnetic core process in the prior art.

[0132] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A process for preparing a low-loss manganese-zinc ferrite core, characterized in that: The steps include: S1 Ingredients Mixing: The following components are composed by weight: 10-15 parts of manganese tetraoxide, 62-79 parts of ferric oxide, and 13-17 parts of zinc oxide are added into a twin-screw mixer for uniform mixing, and auxiliary components are added during the mixing process, wherein the auxiliary components include at least one selected from V2O5, Ca2O3, Nb2O5, TiO2, and SnO2. After the mixing is completed, the mixed raw materials are dispersed by ultrasonic wave; S2 raw material granulation: The mixed raw materials are sand-milled once by a high-pressure micro-powder mill to obtain a mixed slurry with a particle size of 0.5 to 1.0 um, and the mixed slurry is sent to a silo of a granulator, and the mixed slurry is granulated into granules by the granulator; S3 Granule Drying: The granular raw materials are sent into a dryer to dry the granular raw materials, and then the dried granular raw materials are quickly cold-pressed. After the cold-pressing is completed, the granular raw materials are placed in a sintering furnace for pre-sintering; S4 uniform crushing: The pre-sintered granular raw materials are sent to a crusher for crushing to obtain pre-sintered granules with a particle size of 0.1 to 0.4 mm; S5 sintering molding: The pre-sintered particles are poured into the mold in batches, and the filled mold is placed in a sintering furnace. The pre-sintered particles in the mold are completely sintered by the sintering furnace. After sintering, the mold is taken out for rapid cooling. After the mold and the internal magnetic core are cooled to room temperature, the magnetic core is taken out.

2. The process for preparing a low-loss manganese-zinc ferrite core according to claim 1, characterized in that: In the step S5, debris remaining in the mold is cleaned before and after sintering, and the particles filled in the mold are compacted by a cold press before sintering.

3. The process for preparing a low-loss manganese-zinc ferrite core according to claim 1, characterized in that: In step S5, the specific sintering steps are: after heating to 1100-1200°C, keep warm for 3-4 hours in a vacuum environment, then restore the normal oxygen concentration and cool to 500-700°C, keep warm for 2-3 hours, and finally cool to room temperature to obtain a manganese-zinc ferrite core.

4. The process for preparing a low-loss manganese-zinc ferrite core according to claim 1, characterized in that: In the step S1, the ultrasonic dispersion is performed for 5 min to 10 min.

5. The process for preparing a low-loss manganese-zinc ferrite core according to claim 1, characterized in that: The specific steps of pre-sintering in step S3 are: after heating to 750-880° C., pre-sintering for 40-60 minutes.

6. The process for preparing a low-loss manganese-zinc ferrite core according to claim 1, characterized in that: The pre-sintering pressure in step S3 is 50-60 MPa.

7. The process for preparing a low-loss manganese-zinc ferrite core according to claim 1, characterized in that: The equipment used in the steps S1-S5 is a magnetic core preparation equipment, which includes an ultrasonic disperser and a drying machine. The ultrasonic disperser includes a body, a processing chamber opened in the body, and a cover hinged on the body. A mounting seat is slidably arranged in the processing chamber, a processing liner is placed on the mounting seat, a fixing component fixedly matched with the processing liner is arranged in the mounting seat, and a regulating component for controlling the mounting seat to slide up and down is arranged in the body. An ultrasonic generator and a transducer are fixed in the cover, the transducer is electrically connected to the ultrasonic generator, and a variable amplitude rod is fixed on the transducer, the bottom end of the variable amplitude rod is connected to the processing chamber, and an ultrasonic probe is fixed to the bottom end of the variable amplitude rod.

8. The process for preparing a low-loss manganese-zinc ferrite core according to claim 7, characterized in that: The fixing assembly includes a pair of clamping arms slidably connected on the mounting seat, and a bidirectional lead screw rotatably connected in the mounting seat. The threaded sections on both sides of the bidirectional lead screw are threadedly connected to the corresponding clamping arms, and a servo motor 1 is fixed in the mounting seat, a driving gear is coaxially fixed to the output end of the servo motor 1, and a transmission gear is coaxially fixed on the bidirectional lead screw, and the driving gear is meshed with the transmission gear.

9. The process for preparing a low-loss manganese-zinc ferrite core according to claim 7, characterized in that: The control component includes a control motor fixed in the machine body, a plurality of control screws rotatably connected in the machine body, each of the control screws is threadedly connected to a mounting seat, and the bottom end of each control screw is coaxially fixedly connected to a control gear, a toothed disc is rotatably connected in the machine body, the toothed disc is meshed with each control gear, and the output shaft of the control motor is coaxially fixedly connected to the toothed disc.

10. The process for preparing a low-loss manganese-zinc ferrite core according to claim 7, characterized in that: The dryer comprises a tank body and a heating liner rotatably arranged in the tank body, a plurality of flipping strips are spirally fixed in the heating liner, and a limiting groove is provided in the tank body, a limiting ring is coaxially fixed on the surface of the heating liner, the bottom surface of the limiting ring fits the bottom of the limiting groove, a tank cover is hingedly connected to the top of the tank body, a dust collector is fixed on the tank cover, and an input end of the dust collector is connected to the heating liner, a heating element is fixed in the tank body, a driving motor is fixed at the bottom of the tank body, the output shaft of the driving motor is in a cross shape, and a movable groove is provided in the tank body, a bumping cylinder is connected in the movable groove for sliding up and down, a driving shaft is rotatably connected in the bumping cylinder, a compression spring is fixed between the top of the bumping cylinder and the bottom of the movable groove, the top of the driving shaft is coaxially fixedly connected to the heating liner, and a cross groove is provided on the bottom surface of the driving shaft, the cross groove is plugged and matched with the output shaft of the driving motor, a pair of semicircular blocks 1 are fixed to the bumping cylinder, and a pair of semicircular blocks 2 are fixed in the movable groove, and the circular surfaces of the two semicircular blocks 2 are collided and matched with the circular surface of the semicircular block 1.

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