Wide-temperature low-loss manganese zinc ferrite and preparation method thereof

Abstract

The invention discloses wide-temperature low-loss manganese zinc ferrite and a preparation method thereof, and belongs to the technical field of ferrite soft magnetic materials. The manganese zinc ferrite comprises a main component, a first additive and a second additive, the main components comprise Fe2O3, ZnO and MnO; the first additive is prepared from one or more of SnO2, TiO2, Cr2O3, Co3O4 and CuO; and the second additive is prepared from one or more of SiO2, CaCO3, ZrO2, Nb2O5 and Ta2O5. The preparation method comprises the following steps: primary ball milling; primary sintering; performing secondary ball milling; performing granulation; forming is conducted; and secondary sintering. By optimizing the preparation process, additives with different effects are added in batches in the primary ball milling and secondary ball milling processes, and meanwhile, the primary sintering and secondary sintering processes are simply adjusted, so that the magnetic core loss of the manganese-zinc ferrite is effectively reduced, and the temperature stability of the manganese-zinc ferrite is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ferrite soft magnetic materials, and in particular relates to a wide-temperature, low-loss manganese-zinc ferrite and a preparation method thereof. Background Art

[0002] With the development of modern electronic technology, especially the rapid development of the new generation of GaN electronic technology, the demand for switching power supplies is bound to develop in the direction of smaller size and higher efficiency. However, the core loss of manganese-zinc ferrite materials, which is difficult to reduce, has become a major obstacle.

[0003] A large number of literatures point out that the core loss of manganese-zinc ferrite can be divided into three main parts: hysteresis loss Ph, eddy current loss Pe and residual loss Pr. Among them, Pr is more obvious under high-frequency conditions, so for low-frequency power ferrites, the main focus is on reducing Ph and Pe. Forming a uniform grain structure without lattice defects and pores to reduce the resistance of domain wall movement is very important for reducing Ph, and it can also reduce the total loss. There is the following relationship between Pe and grain size: Pe∝D 2 / ρ, where ρ is the material resistivity and D is the grain size. It can be seen that the influence of Pe can be effectively reduced by increasing the material resistivity or reducing the grain size.

[0004] Although the temperature stability and loss characteristics of manganese-zinc ferrite have been improved through the application of additives such as Co3O4, Ti2O3, CaCO3, SiO2, etc. in the traditional production process, structural defects such as abnormal grain growth and excessive cavitation are often encountered in the production process, which hinder the further improvement of the performance of manganese-zinc ferrite; secondly, although the manganese-zinc ferrite produced by this method has an increased grain boundary resistivity and reduced eddy current loss, the hysteresis loss has not decreased significantly, resulting in a still high core loss. Summary of the invention

[0005] The purpose of the present invention is to provide a wide temperature range, low loss manganese zinc ferrite and a preparation method thereof in view of the above problems, so as to solve the problems of poor temperature stability and large core loss of manganese zinc ferrite.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A wide temperature range and low loss manganese zinc ferrite, comprising the following raw materials: a main component, a first additive and a second additive;

[0008] The main components include Fe2O3, ZnO, and MnO;

[0009] The first additive includes one or more of SnO2, TiO2, Cr2O3, Co3O4, and CuO;

[0010] The second additive includes one or more of SiO2, CaCO3, ZrO2, Nb2O5, and Ta2O5.

[0011] Furthermore, the purity of the raw material of the main component should not be less than 98 mol%.

[0012] Furthermore, the main component ratio is 51-59 mol% Fe2O3, 5-10 mol% ZnO, and the rest is MnO.

[0013] Furthermore, Co3O4 and TiO2 in the first additive need to be added simultaneously, wherein the addition amount of Co3O4 is 200-4000ppm, and the addition amount of TiO2 is 50-800ppm.

[0014] Furthermore, SiO2 and CaCO3 in the second additive need to be added simultaneously, wherein the added amount of SiO2 is 10-150ppm, and the added amount of CaCO3 is 200-1500ppm.

[0015] A method for preparing a wide temperature range and low loss manganese zinc ferrite comprises the following steps:

[0016] First ball milling; first sintering; second ball milling; granulation; molding; second sintering.

[0017] Furthermore, the specific steps of the first ball milling are:

[0018] The main component and the first additive are weighed according to the required proportion, put into a ball mill, and ball-milled for 3-10 hours to obtain a slurry, and the slurry is dried to obtain a primary ball-milled powder.

[0019] Furthermore, the specific steps of the primary sintering are:

[0020] The primary ball-milled powder is heated to 900-1200°C at a heating rate of 200-300°C / h in an air atmosphere, kept at this temperature for 1-3h, and cooled in the furnace to obtain a primary sintered powder.

[0021] Furthermore, the specific steps of the secondary ball milling are:

[0022] The second additive is added to the primary sintered powder in proportion, and the powder is put into the ball mill again. The powder is ball milled for 1-5 hours to obtain a slurry. The slurry is dried to obtain a secondary ball milled powder.

[0023] Furthermore, the specific steps of the granulation are:

[0024] According to the total weight of the secondary ball-milled powder, 6-15wt% of polyvinyl alcohol aqueous solution is added, wherein the concentration of the polyvinyl alcohol aqueous solution is 5-10%wt%, and high-speed centrifugal granulation is performed to obtain particles.

[0025] Furthermore, the specific steps of the forming are:

[0026] The granulated particles are pressed into a magnetic ring of T25×15×7.5.

[0027] Furthermore, the specific steps of the secondary sintering are:

[0028] The magnetic ring is sintered in a bell furnace using a balanced oxygen partial pressure, and the temperature is raised from room temperature to 1100-1450°C in 1-6 hours, and maintained at the highest temperature for 0.5-5 hours. The oxygen partial pressure in the sintering atmosphere is controlled in the range of 0.5-5%. After the insulation is completed, a cooling stage is entered. In the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures, and the temperature is cooled from 1100-1450°C to 300-600°C in 1-6 hours to obtain manganese-zinc ferrite.

[0029] Furthermore, the maximum temperature of the primary sintering can be appropriately increased to 1100-1200°C to promote the first additive to participate in the lattice forming process, while reducing the activity of the powder and preventing abnormal grain growth during the secondary sintering process.

[0030] Furthermore, the holding time at the highest temperature of the secondary sintering can be appropriately shortened to 0.5-1 h, so that the second additive can fully react and the grains can be further refined.

[0031] Beneficial effects of the present invention:

[0032] (1) The present invention adopts a reasonable main component ratio and improves the temperature stability of manganese-zinc ferrite through the first additives such as Co3O4 and TiO2, and improves the core loss of manganese-zinc ferrite through the introduction of second additives such as SiO2 and CaCO3.

[0033] (2) The present invention optimizes the preparation process so that the additives enter the ferrite spinel structure, adds ions that can affect the performance of manganese-zinc ferrite by occupying ferrite ion vacancies (i.e., the first additive) in the first ball milling, and appropriately increases the first sintering temperature. In the second ball milling, adds ions that can gather near the grain boundaries and improve the product performance by affecting the formation of grain boundaries and magnetic domain walls (i.e., the second additive), and shortens the secondary sintering time, thereby effectively reducing the core loss of manganese-zinc ferrite and improving the temperature stability of manganese-zinc ferrite. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment provides a wide temperature range and low loss manganese zinc ferrite, which is prepared by the following steps:

[0037] (1) Primary ball milling: Weigh 1 kg of the main component, which contains 53 mol% Fe2O3, 7.5 mol% ZnO, and the remainder MnO, and then weigh 2000 ppm Co3O4 and 200 ppm TiO2, put them into a ball mill, and ball mill for 3 h to obtain a slurry, and dry the slurry to obtain a primary ball milled powder;

[0038] (2) Primary sintering: The primary ball-milled powder is heated to 1100°C at a heating rate of 5°C / min in an air atmosphere, kept at this temperature for 3 h, and cooled in the furnace to obtain a primary sintered powder;

[0039] (3) Secondary ball milling: 20 ppm of SiO2 and 300 ppm of CaCO3 were added to the primary sintered powder, and the powder was put into the ball mill again. The powder was ball milled for 3 h to obtain a slurry, and the slurry was dried to obtain secondary ball milled powder.

[0040] (4) Granulation: according to the total weight of the secondary ball-milled powder, add 10 wt% of a polyvinyl alcohol aqueous solution based on the total weight of the secondary ball-milled powder, wherein the concentration of the polyvinyl alcohol aqueous solution is 10% wt%, and use high-speed centrifugal granulation to obtain particles;

[0041] (5) Molding: The granulated particles are pressed into a magnetic ring of T25×15×7.5;

[0042] (6) Secondary sintering: The magnetic ring is sintered in a bell-shaped furnace using a balanced oxygen partial pressure. The temperature is raised from room temperature to 1250°C in 3 hours and maintained at the highest temperature for 1 hour. The oxygen partial pressure in the sintering atmosphere is controlled within a range of 0.5%. After the insulation is completed, a cooling stage is entered. During the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures. The temperature is cooled from 1250°C to 500°C in 6 hours to obtain manganese-zinc ferrite.

[0043] Example 2

[0044] This embodiment provides a wide temperature range and low loss manganese zinc ferrite, which is prepared by the following steps:

[0045] (1) Primary ball milling: Weigh 1 kg of the main component, which contains 53 mol% Fe2O3, 7.5 mol% ZnO, and the remainder MnO, and then weigh 2000 ppm Co3O4 and 200 ppm TiO2, put them into a ball mill, and ball mill for 3 h to obtain a slurry, and dry the slurry to obtain a primary ball milled powder;

[0046] (2) Primary sintering: The primary ball-milled powder is heated to 1100°C at a heating rate of 10°C / min in an air atmosphere, kept at this temperature for 3 h, and cooled in the furnace to obtain a primary sintered powder;

[0047] (3) Secondary ball milling: 25 ppm of SiO2 and 350 ppm of CaCO3 were added to the primary sintered powder, and the powder was put into the ball mill again. The ball mill was milled for 3 h to obtain a slurry, and the slurry was dried to obtain secondary ball milled powder;

[0048] (4) Granulation: according to the total weight of the secondary ball-milled powder, add 10 wt% of a polyvinyl alcohol aqueous solution based on the total weight of the secondary ball-milled powder, wherein the concentration of the polyvinyl alcohol aqueous solution is 10% wt%, and use high-speed centrifugal granulation to obtain particles;

[0049] (5) Molding: The granulated particles are pressed into a magnetic ring of T25×15×7.5;

[0050] (6) Secondary sintering: The magnetic ring is sintered in a bell-shaped furnace using a balanced oxygen partial pressure. The temperature is raised from room temperature to 1150°C in 3 hours and maintained at the highest temperature for 1.5 hours. The oxygen partial pressure in the sintering atmosphere is controlled within a range of 0.5%. After the insulation is completed, a cooling stage is entered. During the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures. The temperature is cooled from 1150°C to 500°C in 6 hours to obtain manganese-zinc ferrite.

[0051] Example 3

[0052] This embodiment provides a wide temperature range and low loss manganese zinc ferrite, which is prepared by the following steps:

[0053] (1) Primary ball milling: Weigh 1 kg of the main component, which contains 52.75 mol% of Fe2O3, 7.75 mol% of ZnO, and the remainder is MnO, and then weigh 2000 ppm of Co3O4 and 200 ppm of TiO2, put them into a ball mill, and ball mill for 3 h to obtain a slurry, and dry the slurry to obtain a primary ball milled powder;

[0054] (2) Primary sintering: The primary ball-milled powder is heated to 1000°C at a heating rate of 5°C / min in an air atmosphere, kept at this temperature for 3 h, and cooled in the furnace to obtain a primary sintered powder;

[0055] (3) Secondary ball milling: 50 ppm of SiO2 and 400 ppm of CaCO3 were added to the primary sintered powder, and the powder was put into the ball mill again. The ball mill was milled for 3 h to obtain a slurry, and the slurry was dried to obtain secondary ball milled powder;

[0056] (4) Granulation: according to the total weight of the secondary ball-milled powder, add 10 wt% of a polyvinyl alcohol aqueous solution based on the total weight of the secondary ball-milled powder, wherein the concentration of the polyvinyl alcohol aqueous solution is 10% wt%, and use high-speed centrifugal granulation to obtain particles;

[0057] (5) Molding: The granulated particles are pressed into a magnetic ring of T25×15×7.5;

[0058] (6) Secondary sintering: The magnetic ring is sintered in a bell-shaped furnace using a balanced oxygen partial pressure. The temperature is raised from room temperature to 1350°C in 3 hours, and the temperature is maintained at the highest temperature for 3 hours. The oxygen partial pressure in the sintering atmosphere is controlled within a range of 0.4%. After the insulation is completed, a cooling stage is entered. During the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures. The temperature is reduced from 1350°C to 600°C in 5 hours to obtain manganese-zinc ferrite.

[0059] Example 4

[0060] This embodiment provides a wide temperature range and low loss manganese zinc ferrite, which is prepared by the following steps:

[0061] (1) Primary ball milling: Weigh 1 kg of the main component, which contains 52.75 mol% of Fe2O3, 7.75 mol% of ZnO, and the remainder is MnO, and then weigh 3000 ppm of Co3O4 and 400 ppm of TiO2, put them into a ball mill, and ball mill for 3 h to obtain a slurry, and dry the slurry to obtain a primary ball milled powder;

[0062] (2) Primary sintering: The primary ball-milled powder is heated to 1200°C at a heating rate of 5°C / min in an air atmosphere, kept at this temperature for 2 h, and cooled in the furnace to obtain a primary sintered powder;

[0063] (3) Secondary ball milling: Add 20 ppm of SiO2 and 300 ppm of CaCO3 to the primary sintered powder, put it into the ball mill again, and ball mill it for 5 hours to obtain a slurry. The slurry is dried to obtain secondary ball milled powder;

[0064] (4) Granulation: according to the total weight of the secondary ball-milled powder, add 10 wt% of a polyvinyl alcohol aqueous solution based on the total weight of the secondary ball-milled powder, wherein the concentration of the polyvinyl alcohol aqueous solution is 10% wt%, and use high-speed centrifugal granulation to obtain particles;

[0065] (5) Molding: The granulated particles are pressed into a magnetic ring of T25×15×7.5;

[0066] (6) Secondary sintering: The magnetic ring is sintered in a bell-shaped furnace using a balanced oxygen partial pressure. The temperature is raised from room temperature to 1250°C in 3 hours and maintained at the highest temperature for 1 hour. The oxygen partial pressure in the sintering atmosphere is controlled within a range of 0.5%. After the insulation is completed, a cooling stage is entered. During the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures. The temperature is reduced from 1250°C to 600°C in 5 hours to obtain manganese-zinc ferrite.

[0067] Example 5

[0068] This embodiment provides a wide temperature range and low loss manganese zinc ferrite, which is prepared by the following steps:

[0069] (1) Primary ball milling: Weigh 1 kg of the main component, which contains 53.5 mol% of Fe2O3, 7.5 mol% of ZnO, and the remainder is MnO, and then weigh 3000 ppm of Co3O4 and 400 ppm of TiO2, put them into a ball mill, and ball mill for 3 h to obtain a slurry, and dry the slurry to obtain a primary ball milled powder;

[0070] (2) Primary sintering: The primary ball-milled powder is heated to 1200°C at a heating rate of 5°C / min in an air atmosphere, kept at this temperature for 1 hour, and cooled in the furnace to obtain a primary sintered powder;

[0071] (3) Secondary ball milling: Add 20 ppm of SiO2 and 300 ppm of CaCO3 to the primary sintered powder, put it into the ball mill again, and ball mill it for 5 hours to obtain a slurry. The slurry is dried to obtain secondary ball milled powder;

[0072] (4) Granulation: according to the total weight of the secondary ball-milled powder, add 10 wt% of a polyvinyl alcohol aqueous solution based on the total weight of the secondary ball-milled powder, wherein the concentration of the polyvinyl alcohol aqueous solution is 10% wt%, and use high-speed centrifugal granulation to obtain particles;

[0073] (5) Molding: The granulated particles are pressed into a magnetic ring of T25×15×7.5;

[0074] (6) Secondary sintering: The magnetic ring is sintered in a bell-shaped furnace using a balanced oxygen partial pressure. The temperature is raised from room temperature to 1250°C in 3 hours and maintained at the highest temperature for 1 hour. The oxygen partial pressure in the sintering atmosphere is controlled within a range of 0.4%. After the insulation is completed, a cooling stage is entered. During the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures. The temperature is cooled from 1250°C to 400°C in 4 hours to obtain manganese-zinc ferrite.

[0075] Comparative Example 1

[0076] This comparative example provides a manganese-zinc ferrite, which is prepared by the following steps:

[0077] (1) Primary ball milling: Weigh 1 kg of the main component, which contains 53 mol% Fe2O3, 7.5 mol% ZnO, and the remainder MnO, and put it into a ball mill. Mill it for 1 h to obtain a slurry. Dry the slurry to obtain a primary ball milled powder.

[0078] (2) Primary sintering: The primary ball-milled powder is heated to 800°C at a heating rate of 5°C / min in an air atmosphere, kept at this temperature for 3 h, and cooled in the furnace to obtain a primary sintered powder;

[0079] (3) Secondary ball milling: 2000 ppm of Co3O4, 200 ppm of TiO2, 20 ppm of SiO2 and 300 ppm of CaCO3 were added to the primary sintered powder, and the mixture was put into a ball mill again. The mixture was ball milled for 3 h to obtain a slurry, and the slurry was dried to obtain secondary ball milled powder.

[0080] (4) Granulation: according to the total weight of the secondary ball-milled powder, add 10 wt% of a polyvinyl alcohol aqueous solution based on the total weight of the secondary ball-milled powder, wherein the concentration of the polyvinyl alcohol aqueous solution is 10% wt%, and use high-speed centrifugal granulation to obtain particles;

[0081] (5) Molding: The granulated particles are pressed into a magnetic ring of T25×15×7.5;

[0082] (6) Secondary sintering: The magnetic ring is sintered in a bell-shaped furnace using a balanced oxygen partial pressure. The temperature is raised from room temperature to 1250°C in 3 hours and maintained at the highest temperature for 1 hour. The oxygen partial pressure in the sintering atmosphere is controlled within a range of 0.4%. After the insulation is completed, a cooling stage is entered. During the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures. The temperature is cooled from 1250°C to 500°C in 7 hours to obtain manganese-zinc ferrite.

[0083] Comparative Example 2

[0084] This comparative example provides a manganese-zinc ferrite, which is prepared by the following steps:

[0085] (1) Primary ball milling: Weigh 1 kg of the main component, which contains 53 mol% Fe2O3, 7.5 mol% ZnO, and the remainder MnO, and then weigh 2000 ppm Co3O4 and 200 ppm TiO2, put them into a ball mill, and ball mill for 3 h to obtain a slurry, and dry the slurry to obtain a primary ball milled powder;

[0086] (2) Primary sintering: The primary ball-milled powder is heated to 800°C at a heating rate of 5°C / min in an air atmosphere, kept at this temperature for 3 h, and cooled in the furnace to obtain a primary sintered powder;

[0087] (3) Secondary ball milling: 20 ppm of SiO2 and 300 ppm of CaCO3 were added to the primary sintered powder, and the powder was put into the ball mill again. The powder was ball milled for 3 h to obtain a slurry, and the slurry was dried to obtain secondary ball milled powder.

[0088] (4) Granulation: according to the total weight of the secondary ball-milled powder, add 10 wt% of a polyvinyl alcohol aqueous solution based on the total weight of the secondary ball-milled powder, wherein the concentration of the polyvinyl alcohol aqueous solution is 10% wt%, and use high-speed centrifugal granulation to obtain particles;

[0089] (5) Molding: The granulated particles are pressed into a magnetic ring of T25×15×7.5;

[0090] (6) Secondary sintering: The magnetic ring is sintered in a bell-shaped furnace using a balanced oxygen partial pressure. The temperature is raised from room temperature to 1250°C in 3 hours and maintained at the highest temperature for 1 hour. The oxygen partial pressure in the sintering atmosphere is controlled within a range of 0.4%. After the insulation is completed, a cooling stage is entered. During the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures. The temperature is cooled from 1250°C to 500°C in 6 hours to obtain manganese-zinc ferrite.

[0091] Comparative Example 3

[0092] This comparative example provides a manganese-zinc ferrite, which is prepared by the following steps:

[0093] (1) Primary ball milling: Weigh 1 kg of the main component, which contains 53 mol% Fe2O3, 7.5 mol% ZnO, and the remainder MnO, and put it into a ball mill. Mill it for 3 h to obtain a slurry. Dry the slurry to obtain a primary ball milled powder.

[0094] (2) Primary sintering: The primary ball-milled powder is heated to 1100°C at a heating rate of 5°C / min in an air atmosphere, kept at this temperature for 3 h, and cooled in the furnace to obtain a primary sintered powder;

[0095] (3) Secondary ball milling: 2000 ppm of Co3O4, 200 ppm of TiO2, 20 ppm of SiO2 and 300 ppm of CaCO3 were added to the primary sintered powder, and the mixture was put into a ball mill again. The mixture was ball milled for 3 h to obtain a slurry, and the slurry was dried to obtain secondary ball milled powder.

[0096] (4) Granulation: according to the total weight of the secondary ball-milled powder, add 10 wt% of a polyvinyl alcohol aqueous solution based on the total weight of the secondary ball-milled powder, wherein the concentration of the polyvinyl alcohol aqueous solution is 10% wt%, and use high-speed centrifugal granulation to obtain particles;

[0097] (5) Molding: The granulated particles are pressed into a magnetic ring of T25×15×7.5;

[0098] (6) Secondary sintering: The magnetic ring is sintered in a bell-shaped furnace using a balanced oxygen partial pressure. The temperature is raised from room temperature to 1250°C in 3 hours and maintained at the highest temperature for 1 hour. The oxygen partial pressure in the sintering atmosphere is controlled within a range of 0.5%. After the insulation is completed, a cooling stage is entered. During the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures. The temperature is cooled from 1250°C to 500°C in 6 hours to obtain manganese-zinc ferrite.

[0099] Performance tests were performed on Examples 1 to 5 and Comparative Examples 1 to 3, and the results are shown in Table 1:

[0100] Table 1

[0101]

[0102] It can be seen from Table 1 that the manganese-zinc ferrites prepared in Examples 1 to 5 have lower core loss at 25-140°C, higher saturation flux density at 25-100°C, and better temperature stability and low loss performance.

[0103] The conventional preparation method of manganese-zinc ferrite is to sinter the main component at a lower temperature, and the additive is added during the secondary ball milling process (refer to comparative example 1). Comparison between comparative example 1 and embodiment 1 shows that, when the main component and the additive component are consistent, by optimizing the preparation process, the additives with different functions are added in batches, and the primary sintering and secondary sintering processes are simply adjusted, the temperature stability and saturation magnetic flux density of manganese-zinc ferrite can be improved, and the loss of manganese-zinc ferrite can be reduced. Comparison between comparative examples 2 and 3 and embodiment 1 shows that only adjusting the order of adding additives or only adjusting the sintering process is not only unhelpful to reducing the core loss and improving the saturation magnetic flux density, but may deteriorate the performance. The two must be matched, that is, the order of adding additives and the sintering process must be adjusted at the same time, so that the process advantage can be maximized.

[0104] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0105] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wide temperature and low loss manganese-zinc ferrite, characterized in that: The raw materials include: a main component, a first additive, and a second additive; The main components include Fe2O3, ZnO, and MnO; The first additive includes one or more of SnO2, TiO2, Cr2O3, Co3O4, and CuO; The second additive includes one or more of SiO2, CaCO3, ZrO2, Nb2O5, and Ta2O5.

2. A wide temperature and low loss manganese-zinc ferrite according to claim 1, characterized in that: The purity of the raw material of the main component should not be less than 98 mol%.

3. The wide temperature and low loss manganese-zinc ferrite according to claim 1, characterized in that: The main component ratio is 51-59 mol% Fe2O3, 5-10 mol% ZnO, and the rest is MnO.

4. The wide temperature and low loss manganese-zinc ferrite according to claim 1, characterized in that: Co3O4 and TiO2 in the first additive need to be added simultaneously, wherein the addition amount of Co3O4 is 200-4000ppm, and the addition amount of TiO2 is 50-800ppm.

5. The wide temperature and low loss manganese-zinc ferrite according to claim 1, characterized in that: SiO2 and CaCO3 in the second additive need to be added simultaneously, wherein the added amount of SiO2 is 10-150ppm, and the added amount of CaCO3 is 200-1500ppm.

6. A method for preparing a wide temperature range and low loss manganese zinc ferrite according to any one of claims 1 to 5, characterized in that: The steps include: First ball milling; first sintering; second ball milling; granulation; molding; second sintering.

7. The method for preparing a wide temperature range and low loss manganese zinc ferrite according to claim 6, characterized in that: The specific steps of the first ball milling are: The main component and the first additive are weighed according to the required proportion, put into a ball mill, and ball-milled for 3-10 hours to obtain a slurry, and the slurry is dried to obtain a primary ball-milled powder.

8. The method for preparing a wide temperature range and low loss manganese zinc ferrite according to claim 6, characterized in that: The specific steps of the primary sintering are: The primary ball-milled powder is heated to 900-1200°C at a heating rate of 200-300°C / h in an air atmosphere, kept at this temperature for 1-3h, and cooled in the furnace to obtain a primary sintered powder.

9. The method for preparing a wide temperature range and low loss manganese zinc ferrite according to claim 6, characterized in that: The specific steps of the secondary ball milling are: The second additive is added to the primary sintered powder in proportion, and the powder is put into the ball mill again. The powder is ball milled for 1-5 hours to obtain a slurry. The slurry is dried to obtain a secondary ball milled powder.

10. The method for preparing a wide temperature range and low loss manganese zinc ferrite according to claim 6, characterized in that: The specific steps of the granulation are: According to the total weight of the secondary ball-milled powder, 6-15wt% of polyvinyl alcohol aqueous solution is added, wherein the concentration of the polyvinyl alcohol aqueous solution is 5-10%wt%, and high-speed centrifugal granulation is performed to obtain particles.

11. The method for preparing a wide temperature range and low loss manganese zinc ferrite according to claim 6, characterized in that: The specific steps of the molding are: The granulated particles are pressed into a magnetic ring of T25×15×7.

5.

12. The method for preparing a wide temperature range and low loss manganese zinc ferrite according to claim 6, characterized in that: The specific steps of the secondary sintering are: The magnetic ring is sintered in a bell furnace using a balanced oxygen partial pressure, and the temperature is raised from room temperature to 1100-1450°C in 1-6 hours, and maintained at the highest temperature for 0.5-5 hours. The oxygen partial pressure in the sintering atmosphere is controlled in the range of 0.4-5%. After the insulation is completed, a cooling stage is entered. In the cooling stage, the atmosphere is maintained at a balanced oxygen partial pressure at different temperatures, and the temperature is cooled from 1100-1450°C to 300-600°C in 1-6 hours to obtain manganese-zinc ferrite.

13. The method for preparing a wide temperature range and low loss manganese zinc ferrite according to claim 6, characterized in that: The maximum temperature of the primary sintering can be appropriately increased to 1100-1200°C to promote the first additive to participate in the lattice forming process, while reducing the activity of the powder and preventing abnormal grain growth during the secondary sintering process.

14. The method for preparing a wide temperature range and low loss manganese zinc ferrite according to claim 6, characterized in that: The holding time at the highest temperature of the secondary sintering can be appropriately shortened to 0.5-1h, so that the second additive can fully react and the grains can be further refined.

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