Manganese zinc ferrite material as well as preparation method and application thereof

Abstract

The invention provides a manganese zinc ferrite material as well as a preparation method and application thereof. The manganese zinc ferrite material is prepared from main components and auxiliary components, the main component is prepared from the following components in molar ratio: 51.5 to 53.0 mol percent of ferric oxide, 17.0 to 18.5 mol percent of zinc oxide and 29.0 to 30.0 mol percent of manganese oxide; the auxiliary components comprise the following components according to the total weight of the main components: 200 to 2000 ppm of nano-scale bismuth oxide, 200 to 2000 ppm of nano-scale calcium carbonate, 200 to 2000 ppm of nano-scale molybdenum oxide, and 0 to 4000 ppm of nano-scale cobalt oxide. By optimizing the components and the proportion of the ferrite material, improving the preparation process and organically combining the formula and the process, the ferrite material with high magnetic conductivity, high Curie temperature, wide frequency and wide temperature is finally prepared, and large-scale popularization and application are facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of ferrite materials, and relates to a manganese-zinc ferrite material, and in particular to a manganese-zinc ferrite material and a preparation method and application thereof. Background Art

[0002] At present, high permeability manganese-zinc ferrite is widely used in the fields of electronic signal transmission, anti-electromagnetic interference technology, environmental protection and energy saving, automotive electronics market, etc., especially when manganese-zinc ferrite is used in electronic products and devices, it is often necessary to improve its comprehensive performance. For example, automotive electronics requires wide temperature, wide frequency and high permeability manganese-zinc soft magnetic ferrite. In hot areas, if a car needs to be stopped during full load use, the heat from the car exhaust pipe will make the temperature of the engine room as high as 100°C or more, while in cold areas, the outdoor temperature will even be below -40°C. In extreme weather, if the ferrite inside the car is to operate normally, it must have a low change in permeability within the operating temperature range, that is, it must have excellent temperature characteristics.

[0003] CN101050108A discloses a wide-band, low-loss, high-permeability manganese-zinc ferrite material and its preparation method, which contains main components including manganese oxide, zinc oxide and iron oxide, and auxiliary components added to the main components including one or two of sodium oxide and potassium oxide, bismuth oxide, molybdenum oxide and vanadium oxide; wherein the main components are composed of: 21.5-26.5 mol% of manganese oxide calculated as MnO, 20.5-25.5 mol% of zinc oxide calculated as ZnO, and the rest is iron oxide. The manganese-zinc ferrite material prepared by the invention only has a magnetic permeability that does not drop at 100KHz, and it is not mentioned whether it has a high Curie temperature, and the preparation process still has a large room for improvement.

[0004] CN101696107A discloses a Mn-Zn ferrite material with high initial magnetic permeability and high Curie temperature and a preparation method thereof. In the ferrite material, iron oxide is in the range of 50-55 mol%, zinc oxide is in the range of 15-25 mol%, and the rest is manganese oxide; the auxiliary agent includes calcium oxide 50-400 ppm, bismuth oxide 50-1000 ppm and molybdenum oxide 50-800 ppm. The ferrite material prepared by the invention has the characteristics of initial magnetic permeability μi of 8000-12000 and Curie temperature greater than 170°C, but the magnetic permeability temperature characteristic will have a negative temperature coefficient phenomenon at 25-100°C, that is, the temperature characteristic is significantly reduced.

[0005] It can be seen that how to provide a manganese-zinc ferrite material and a preparation method thereof, optimize the components and ratios of the ferrite material, improve the preparation process, organically combine the formula and the process, and finally obtain a ferrite material with high magnetic permeability, high Curie temperature, wide frequency band and wide temperature, has become an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a manganese-zinc ferrite material and a preparation method and application thereof. By optimizing the components and ratios of the ferrite material and improving the preparation process, the formula and process are organically combined to finally obtain a ferrite material with high magnetic permeability, high Curie temperature, wide frequency band and wide temperature range, which is conducive to large-scale promotion and application.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a manganese-zinc ferrite material, wherein the manganese-zinc ferrite material is made of a main component and an auxiliary component.

[0009] According to the molar ratio, the main components include: 51.5-53.0 mol% of iron oxide, 17.0-18.5 mol% of zinc oxide, and 29.0-30.0 mol% of manganese oxide.

[0010] According to the total weight of the main components, the auxiliary components include: 200-2000ppm of nano-grade bismuth oxide, 200-2000ppm of nano-grade calcium carbonate, 200-2000ppm of nano-grade molybdenum oxide, and 0-4000ppm of nano-grade cobalt oxide.

[0011] In the present invention, the molar ratio of the main components is calculated based on the total amount of the main component substances.

[0012] In the present invention, the average particle size of the nano-sized bismuth oxide, nano-sized calcium carbonate, nano-sized molybdenum oxide and nano-sized cobalt oxide is independently 100-200 nm, for example, it can be 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm or 200 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] The present invention optimizes and controls the ratio of main components and the types and contents of auxiliary components on the basis of traditional manganese-zinc ferrite materials. The obtained manganese-zinc ferrite material has high initial magnetic permeability and low temperature coefficient in the temperature range of -40 to 160°C, and the 300KHz magnetic permeability μi is above 10000, and the Curie temperature Tc is above 160°C. It has excellent comprehensive performance and is conducive to large-scale promotion and application.

[0014] In the present invention, the molar ratio of the iron oxide is 51.5-53.0 mol%, for example, it can be 51.5 mol%, 51.6 mol%, 51.8 mol%, 52.0 mol%, 52.2 mol%, 52.4 mol%, 52.6 mol%, 52.8 mol% or 53.0 mol%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] In the present invention, the molar ratio of zinc oxide is 17.0-18.5 mol%, for example, it can be 17.0 mol%, 17.2 mol%, 17.4 mol%, 17.6 mol%, 17.8 mol%, 18.0 mol%, 18.2 mol%, 18.4 mol% or 18.5 mol%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] In the present invention, the molar ratio of manganese oxide is 29.0-30.0 mol%, for example, it can be 29.0 mol%, 29.1 mol%, 29.2 mol%, 29.3 mol%, 29.4 mol%, 29.5 mol%, 29.6 mol%, 29.7 mol%, 29.8 mol%, 29.9 mol% or 30.0 mol%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] In the present invention, the contents of the nano-sized bismuth oxide, nano-sized calcium carbonate and nano-sized molybdenum oxide are independently 200-2000 ppm, for example, 200 ppm, 400 ppm, 600 ppm, 800 ppm, 1000 ppm, 1200 ppm, 1400 ppm, 1600 ppm, 1800 ppm or 2000 ppm, but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] In the present invention, the content of the nano-scale cobalt oxide is 0-4000ppm, for example, it can be 0ppm, 10ppm, 100ppm, 500ppm, 1000ppm, 1500ppm, 2000ppm, 2500ppm, 3000ppm, 3500ppm or 4000ppm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] In the present invention, the anisotropy constant K1 of cobalt oxide is greater than 0. 2+With the addition of ions, the K1 value contributed by them decreases sharply with the increase of temperature, so that the offset point of K1=0 is lower than the temperature range of Curie temperature.

[0020] Preferably, in terms of molar ratio, the main components include: 52.0-52.5 mol % of iron oxide, 17.5-18.1 mol % of zinc oxide, and the remainder of manganese oxide.

[0021] In a second aspect, the present invention provides a method for preparing the manganese-zinc ferrite material as described in the first aspect, wherein the preparation method comprises mixing, pre-sintering, ball milling, tempering, granulation, molding and sintering in sequence.

[0022] The present invention adds tempering treatment on the basis of the traditional ferrite preparation method, so that the distribution of various components in the material is more uniform, and each element ion fully exerts its characteristics, thereby obtaining a ferrite material with high magnetic permeability, high Curie temperature, wide frequency and wide temperature, which is conducive to large-scale promotion and application.

[0023] Preferably, the mixing comprises: weighing the main components according to the molar ratio and sequentially performing wet ball milling and drying treatments.

[0024] Preferably, the pre-sintering comprises: pre-sintering the mixed material in an air atmosphere at 700-800° C. for 2-3 hours to obtain a pre-sintered powder.

[0025] In the present invention, the pre-firing temperature is 700-800°C, for example, it can be 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, 760°C, 770°C, 780°C, 790°C or 800°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] In the present invention, the pre-burning time is 2-3h, for example, it can be 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the ball milling comprises: adding auxiliary components in a designed proportion to the pre-burnt powder and performing wet ball milling for 60-90 minutes, and obtaining ferrite powder after drying.

[0028] In the present invention, the wet ball milling time is 60-90 min, for example, it can be 60 min, 65 min, 70 min, 75 min, 80 min, 85 min or 90 min, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the tempering includes: tempering the ferrite powder at 700-850°C, for example, it can be 700°C, 720°C, 740°C, 760°C, 780°C, 800°C, 820°C, 840°C or 850°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] In the present invention, the temperature of the tempering treatment has a significant effect on the distribution of the components in the material. When the temperature of the tempering treatment is lower than 700°C, the distribution uniformity of the components in the material is poor, thereby affecting the product performance; when the temperature of the tempering treatment is higher than 850°C, the distribution uniformity of the components in the material is not significantly improved, but will cause unnecessary increase in energy consumption and cost to a certain extent.

[0031] Preferably, the granulation comprises: adding a binder to the ferrite powder and sequentially grinding, sieving, stirring and granulating to obtain ferrite particles.

[0032] Preferably, the adhesive comprises a polyvinyl alcohol-based adhesive, such as polyvinyl butyral (PVB).

[0033] Preferably, the ratio of the binder to the ferrite powder is 7-9wt%, for example, it can be 7wt%, 7.2wt%, 7.4wt%, 7.6wt%, 7.8wt%, 8wt%, 8.2wt%, 8.4wt%, 8.6wt%, 8.8wt% or 9wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the granulation comprises spray granulation.

[0035] Preferably, the forming comprises: pressing the ferrite particles into a ferrite blank by a press.

[0036] Preferably, the size of the ferrite blank is (20-30) cm×(10-20) cm×(5-10) cm, for example, it can be 20cm×10cm×5cm, 22cm×12cm×6cm, 24cm×14cm×7cm, 26cm×16cm×8cm, 28cm×18cm×9cm or 30cm×20cm×10cm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the sintering includes three stages, including a first sintering, a second sintering and a third sintering performed sequentially.

[0038] Preferably, the first sintering is carried out in a nitrogen atmosphere with an oxygen content controlled to 19-21 vol%, for example, it can be 19 vol%, 19.2 vol%, 19.4 vol%, 19.6 vol%, 19.8 vol%, 20 vol%, 20.2 vol%, 20.4 vol%, 20.6 vol%, 20.8 vol% or 21 vol%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the first sintering temperature is 500-700°C, for example, it can be 500°C, 520°C, 540°C, 560°C, 580°C, 600°C, 620°C, 640°C, 660°C, 680°C or 700°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the first sintering time is 1-5 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h or 5 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, the second sintering is carried out in a nitrogen atmosphere with an oxygen content controlled to 19-21 vol%, for example, it can be 19 vol%, 19.2 vol%, 19.4 vol%, 19.6 vol%, 19.8 vol%, 20 vol%, 20.2 vol%, 20.4 vol%, 20.6 vol%, 20.8 vol% or 21 vol%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, the temperature of the second sintering is 1000-1100°C, for example, it can be 1000°C, 1010°C, 1020°C, 1030°C, 1040°C, 1050°C, 1060°C, 1070°C, 1080°C, 1090°C or 1100°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] Preferably, the second sintering time is 4-8 h, for example, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h or 8 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the third sintering is carried out in a nitrogen atmosphere with an oxygen content controlled at 3-8 vol%, for example, it can be 3 vol%, 3.5 vol%, 4 vol%, 4.5 vol%, 5 vol%, 5.5 vol%, 6 vol%, 6.5 vol%, 7 vol%, 7.5 vol% or 8 vol%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the temperature of the third sintering is 1250-1360°C, for example, it can be 1250°C, 1260°C, 1280°C, 1300°C, 1320°C, 1340°C or 1360°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] Preferably, the third sintering time is 5-7h, for example, it can be 5h, 5.2h, 5.4h, 5.6h, 5.8h, 6h, 6.2h, 6.4h, 6.6h, 6.8h or 7h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] Preferably, after the sintering, cooling is performed under a balanced oxygen partial pressure.

[0048] As a preferred technical solution of the second aspect of the present invention, the preparation method comprises the following steps:

[0049] (1) Mixing: Weigh the main components according to the molar ratio and perform wet ball milling and drying in sequence;

[0050] (2) Pre-burning: Pre-burn the mixed material in an air atmosphere at 700-800°C for 2-3 hours to obtain a pre-burned powder;

[0051] (3) Ball milling: Add the designed proportion of auxiliary components to the pre-burned powder and perform wet ball milling for 60-90 minutes, and then dry to obtain ferrite powder;

[0052] (4) Tempering: Temper the ferrite powder at 700-850°C;

[0053] (5) Granulation: adding 7-9 wt% of a polyvinyl alcohol-based binder to the ferrite powder and sequentially grinding, sieving, stirring and spray granulating to obtain ferrite particles;

[0054] (6) Molding: The ferrite particles are pressed into a ferrite blank having a size of (20-30) cm×(10-20) cm×(5-10) cm by a press;

[0055] (7) Sintering: First, the ferrite blank is subjected to a first sintering at 500-700°C for 1-5 h in a nitrogen atmosphere with an oxygen content of 19-21 vol%, then the ferrite blank is subjected to a second sintering at 1000-1100°C for 4-8 h in a nitrogen atmosphere with an oxygen content of 19-21 vol%, and finally the ferrite blank is subjected to a third sintering at 1250-1360°C for 5-7 h in a nitrogen atmosphere with an oxygen content of 3-8 vol%, and then cooled under a balanced oxygen partial pressure to obtain a manganese-zinc ferrite material.

[0056] In a third aspect, the present invention provides an application of the manganese-zinc ferrite material as described in the first aspect, wherein the manganese-zinc ferrite material is used to prepare a transformer core.

[0057] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] (1) The present invention optimizes and controls the ratio of the main components and the types and contents of the auxiliary components on the basis of the traditional manganese-zinc ferrite material. The obtained manganese-zinc ferrite material has a high initial magnetic permeability and a low temperature coefficient in the temperature range of -40 to 160°C, and the magnetic permeability μi at 300KHz is more than 10,000, and the Curie temperature Tc is more than 160°C. It has excellent comprehensive performance and is conducive to large-scale promotion and application;

[0060] (2) The present invention adds a tempering treatment to the traditional ferrite preparation method, so that the distribution of the various components in the material is more uniform, and the ions of each element fully exert their characteristics, thereby obtaining a ferrite material with high magnetic permeability, high Curie temperature, wide frequency and wide temperature. DETAILED DESCRIPTION

[0061] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0062] Example 1

[0063] This embodiment provides a manganese-zinc ferrite material and a preparation method thereof. The manganese-zinc ferrite material is prepared from a main component and an auxiliary component.

[0064] According to the molar ratio, the main components include: 52.0 mol% of iron oxide, 18.1 mol% of zinc oxide, and 29.9 mol% of manganese oxide.

[0065] Based on the total weight of the main components, the auxiliary components include: 400 ppm of nano-grade bismuth oxide, 200 ppm of nano-grade calcium carbonate, 200 ppm of nano-grade molybdenum oxide, and 1500 ppm of nano-grade cobalt oxide.

[0066] In this embodiment, the preparation method comprises the following steps:

[0067] (1) Mixing: Weigh the main components according to the molar ratio and perform wet ball milling and drying in sequence;

[0068] (2) Pre-calcination: pre-calcining the mixed material in an air atmosphere at 750°C for 2.5 hours to obtain a pre-calcined powder;

[0069] (3) Ball milling: Add the designed proportion of auxiliary components to the pre-burned powder and perform wet ball milling for 70 minutes, and then dry to obtain ferrite powder;

[0070] (4) Tempering: Temper the ferrite powder at 750°C;

[0071] (5) Granulation: Add 8 wt% of polyvinyl butyral (PVB) to the ferrite powder and grind, sieve, stir and spray granulate in sequence to obtain ferrite particles;

[0072] (6) Molding: The ferrite particles are pressed into a ferrite blank with a size of 25 cm × 15 cm × 8 cm by a press;

[0073] (7) Sintering: First, the ferrite blank is subjected to a first sintering at 600°C for 3 h in a nitrogen atmosphere with an oxygen content of 20 vol%, then the ferrite blank is subjected to a second sintering at 1050°C for 6 h in a nitrogen atmosphere with an oxygen content of 20 vol%, and finally the ferrite blank is subjected to a third sintering at 1300°C for 6 h in a nitrogen atmosphere with an oxygen content of 5 vol%, and then the temperature is lowered under a balanced oxygen partial pressure to obtain a manganese-zinc ferrite material.

[0074] Example 2

[0075] This embodiment provides a manganese-zinc ferrite material and a preparation method thereof. The manganese-zinc ferrite material is prepared from a main component and an auxiliary component.

[0076] According to the molar ratio, the main components include: 52.15 mol% of iron oxide, 18.0 mol% of zinc oxide, and 29.85 mol% of manganese oxide.

[0077] Based on the total weight of the main components, the auxiliary components include: 450 ppm of nano-grade bismuth oxide, 400 ppm of nano-grade calcium carbonate, 200 ppm of nano-grade molybdenum oxide, and 2000 ppm of nano-grade cobalt oxide.

[0078] In this embodiment, the preparation method comprises the following steps:

[0079] (1) Mixing: Weigh the main components according to the molar ratio and perform wet ball milling and drying in sequence;

[0080] (2) Pre-burning: Pre-burn the mixed material in an air atmosphere at 700°C for 3 hours to obtain a pre-burned powder;

[0081] (3) Ball milling: Add the designed proportion of auxiliary components to the pre-burned powder and perform wet ball milling for 60 minutes, and then dry to obtain ferrite powder;

[0082] (4) Tempering: Temper the ferrite powder at 700°C;

[0083] (5) Granulation: Add 7 wt % of polyvinyl butyral (PVB) to the ferrite powder and grind, sieve, stir and spray granulate in sequence to obtain ferrite particles;

[0084] (6) Molding: The ferrite particles are pressed into a ferrite blank with a size of 20 cm × 10 cm × 5 cm by a press;

[0085] (7) Sintering: First, the ferrite blank is subjected to a first sintering at 500°C for 5 h in a nitrogen atmosphere with an oxygen content of 19 vol%, then a second sintering at 1000°C for 8 h in a nitrogen atmosphere with an oxygen content of 19 vol%, and finally a third sintering at 1250°C for 7 h in a nitrogen atmosphere with an oxygen content of 3 vol%, and then cooled under a balanced oxygen partial pressure to obtain a manganese-zinc ferrite material.

[0086] Example 3

[0087] This embodiment provides a manganese-zinc ferrite material and a preparation method thereof. The manganese-zinc ferrite material is prepared from a main component and an auxiliary component.

[0088] According to the molar ratio, the main components include: 52.23 mol% of iron oxide, 17.83 mol% of zinc oxide, and 29.94 mol% of manganese oxide.

[0089] Based on the total weight of the main components, the auxiliary components include: 450 ppm of nano-grade bismuth oxide, 600 ppm of nano-grade calcium carbonate, 200 ppm of nano-grade molybdenum oxide, and 2500 ppm of nano-grade cobalt oxide.

[0090] In this embodiment, the preparation method comprises the following steps:

[0091] (1) Mixing: Weigh the main components according to the molar ratio and perform wet ball milling and drying in sequence;

[0092] (2) Pre-burning: Pre-burn the mixed material in an air atmosphere at 800°C for 2 hours to obtain a pre-burned powder;

[0093] (3) Ball milling: Add the designed proportion of auxiliary components to the pre-calcined powder and perform wet ball milling for 90 minutes, and then dry to obtain ferrite powder;

[0094] (4) Tempering: Temper the ferrite powder at 850°C;

[0095] (5) Granulation: Add 9 wt % of polyvinyl butyral (PVB) to the ferrite powder and grind, sieve, stir and spray granulate in sequence to obtain ferrite particles;

[0096] (6) Molding: The ferrite particles are pressed into a ferrite blank with a size of 30 cm × 20 cm × 10 cm by a press;

[0097] (7) Sintering: First, the ferrite blank is subjected to a first sintering at 700°C for 1 h in a nitrogen atmosphere with an oxygen content of 21 vol%, then a second sintering at 1100°C for 4 h in a nitrogen atmosphere with an oxygen content of 21 vol%, and finally a third sintering at 1360°C for 5 h in a nitrogen atmosphere with an oxygen content of 8 vol%, and then cooled under a balanced oxygen partial pressure to obtain a manganese-zinc ferrite material.

[0098] Example 4

[0099] This embodiment provides a manganese-zinc ferrite material and a preparation method thereof. In the preparation method, except that the tempering temperature in step (4) is changed to 650° C., the remaining steps and conditions are the same as those in Example 1, and thus are not described in detail here.

[0100] Comparative Example 1

[0101] This comparative example provides a manganese-zinc ferrite material and a preparation method thereof, except that the auxiliary components are changed to: 400 ppm of nano-grade bismuth oxide, 200 ppm of nano-grade calcium carbonate, 200 ppm of nano-grade molybdenum oxide, and 1500 ppm of nano-grade vanadium pentoxide, the remaining steps and conditions are the same as those in Example 1, so they are not repeated here.

[0102] Comparative Example 2

[0103] This comparative example provides a manganese-zinc ferrite material and a preparation method thereof, except that the auxiliary components are changed to: 0.01wt% of nano-grade bismuth oxide, 0.02wt% of nano-grade calcium carbonate, 0.02wt% of nano-grade indium oxide, and 0.02wt% of nano-grade tantalum pentoxide, the remaining steps and conditions are the same as those in Example 1, so they are not repeated here.

[0104] Comparative Example 3

[0105] This comparative example provides a manganese-zinc ferrite material and a preparation method thereof. Except for removing the tempering treatment in step (4), that is, directly granulating the ferrite powder obtained by ball milling, the remaining steps and conditions are the same as those in Example 1, and thus are not described in detail here.

[0106] The magnetic permeability μi and Curie temperature Tc of the manganese-zinc ferrite materials obtained in Examples 1-4 and Comparative Examples 1-3 are shown in Table 1 below.

[0107] Table 1

[0108]

[0109]

[0110] It can be seen from Table 1 that compared with Examples 1-4, the frequency characteristics of the manganese-zinc ferrite materials obtained in Comparative Examples 1-3 are significantly deteriorated, and the electronic devices cannot be guaranteed to work normally within this temperature range.

[0111] The initial magnetic permeability μi of the manganese-zinc ferrite materials obtained in Examples 1-4 and Comparative Examples 1-3 at -40 to 160°C is shown in Table 2 below.

[0112] Table 2

[0113]

[0114] It can be seen from Table 2 that since the performance, process and auxiliary component range of Comparative Examples 1-3 are significantly different from those of Examples 1-4, especially since Comparative Examples 1 and 2 do not add auxiliary Co ions, the temperature characteristics of the magnetic permeability vary too much, resulting in the electronic device being unable to work normally within the temperature range.

[0115] It can be seen that the present invention optimizes and controls the ratio of the main components and the types and contents of the auxiliary components on the basis of the traditional manganese-zinc ferrite material. The obtained manganese-zinc ferrite material has a high initial magnetic permeability and a low temperature coefficient in the temperature range of -40 to 160°C, and the 300KHz magnetic permeability μi is above 10,000, and the Curie temperature Tc is above 160°C. It has excellent comprehensive performance and is conducive to large-scale promotion and application.

[0116] In addition, the present invention adds tempering treatment on the basis of the traditional ferrite preparation method, so that the distribution of each component in the material is more uniform, and each element ion fully exerts its characteristics, thereby obtaining a ferrite material with high magnetic permeability, high Curie temperature, broadband and wide temperature.

[0117] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A manganese-zinc ferrite material, characterized in that: The manganese-zinc ferrite material is made of a main component and an auxiliary component; According to the molar ratio, the main components include: 51.5-53.0 mol% of iron oxide, 17.0-18.5 mol% of zinc oxide, and 29.0-30.0 mol% of manganese oxide; According to the total weight of the main components, the auxiliary components include: 200-2000ppm of nano-grade bismuth oxide, 200-2000ppm of nano-grade calcium carbonate, 200-2000ppm of nano-grade molybdenum oxide, and 0-4000ppm of nano-grade cobalt oxide.

2. The manganese-zinc ferrite material according to claim 1, characterized in that: According to the molar ratio, the main components include: 52.0-52.5 mol% of iron oxide, 17.5-18.1 mol% of zinc oxide, and the rest is manganese oxide.

3. A method for preparing the manganese-zinc ferrite material as claimed in claim 1 or 2, characterized in that: The preparation method comprises mixing, pre-sintering, ball milling, tempering, granulation, molding and sintering in sequence.

4. The preparation method according to claim 3, characterized in that: The mixing comprises: weighing the main components according to the molar ratio and sequentially performing wet ball milling and drying treatments; Preferably, the pre-sintering comprises: pre-sintering the mixed material in an air atmosphere at 700-800° C. for 2-3 hours to obtain a pre-sintered powder.

5. The preparation method according to claim 4, characterized in that: The ball milling comprises: adding auxiliary components of designed proportion to the pre-burned powder and performing wet ball milling for 60-90 minutes, and drying to obtain ferrite powder; Preferably, the tempering comprises: performing a tempering treatment on the ferrite powder at 700-850°C.

6. The preparation method according to claim 5, characterized in that: The granulation comprises: adding a binder to the ferrite powder and sequentially grinding, sieving, stirring and granulating to obtain ferrite particles; Preferably, the binder comprises a polyvinyl alcohol-based binder; Preferably, the binder accounts for 7-9wt% of the ferrite powder; Preferably, the granulation comprises spray granulation.

7. The preparation method according to claim 6, characterized in that: The forming comprises: pressing ferrite particles into ferrite blanks through a press; Preferably, the size of the ferrite blank is (20-30) cm×(10-20) cm×(5-10) cm.

8. The preparation method according to claim 7, characterized in that: The sintering includes three stages, including a first sintering, a second sintering and a third sintering performed sequentially; Preferably, the first sintering is performed under a nitrogen atmosphere with an oxygen content controlled to be 19-21 vol%; Preferably, the temperature of the first sintering is 500-700°C; Preferably, the first sintering time is 1-5h; Preferably, the second sintering is performed under a nitrogen atmosphere with an oxygen content controlled to be 19-21 vol%; Preferably, the temperature of the second sintering is 1000-1100°C; Preferably, the second sintering time is 4-8h; Preferably, the third sintering is performed in a nitrogen atmosphere with an oxygen content controlled to be 3-8 vol%; Preferably, the temperature of the third sintering is 1250-1360°C; Preferably, the third sintering time is 5-7h; Preferably, after the sintering, cooling is performed under a balanced oxygen partial pressure.

9. The preparation method according to any one of claims 3 to 8, characterized in that: The preparation method comprises the following steps: (1) Mixing: Weigh the main components according to the molar ratio and perform wet ball milling and drying in sequence; (2) Pre-burning: Pre-burn the mixed material in an air atmosphere at 700-800°C for 2-3 hours to obtain a pre-burned powder; (3) Ball milling: Add the designed proportion of auxiliary components to the pre-burned powder and perform wet ball milling for 60-90 minutes, and then dry to obtain ferrite powder; (4) Tempering: Temper the ferrite powder at 700-850°C; (5) Granulation: adding 7-9 wt% of a polyvinyl alcohol-based binder to the ferrite powder and sequentially grinding, sieving, stirring and spray granulating to obtain ferrite particles; (6) Molding: The ferrite particles are pressed into a ferrite blank having a size of (20-30) cm×(10-20) cm×(5-10) cm by a press; (7) Sintering: First, the ferrite blank is subjected to a first sintering at 500-700°C for 1-5 h in a nitrogen atmosphere with an oxygen content of 19-21 vol%, then the ferrite blank is subjected to a second sintering at 1000-1100°C for 4-8 h in a nitrogen atmosphere with an oxygen content of 19-21 vol%, and finally the ferrite blank is subjected to a third sintering at 1250-1360°C for 5-7 h in a nitrogen atmosphere with an oxygen content of 3-8 vol%, and then cooled under a balanced oxygen partial pressure to obtain a manganese-zinc ferrite material.

10. An application of the manganese-zinc ferrite material as claimed in claim 1 or 2, characterized in that: The manganese-zinc ferrite material is used for preparing a transformer magnetic core.

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