Wide temperature range material applicable to low frequency band and preparation method thereof

Abstract

The present application provides a wide temperature range material for low frequency band applications and a method for preparing the same. [Solution] By producing a certain amount of cobalt ferrite and iron ferrite using the raw materials Fe2O3, ZnO, and Co2O3 in a specific compounding ratio, the negative magnetocrystalline anisotropy constant K1 in the main phase of MnZn ferrite can be effectively offset, and the sintering process can be controlled to have a specific oxygen content. This allows for the preparation of a material with low magnetic loss that can be used in the low frequency range of 65 to 75 kHz and a wide temperature range of 25 to 120°C, and has the prospect of being widely used in large-scale industrial applications.

Description

[Technical Field]

[0001] The present application relates to the technical field of magnetic materials, for example, to wide temperature range materials for low frequency band applications and methods for preparing same. [Background technology]

[0002] Soft ferrites are widely used as important functional materials in electronic and electrical equipment. MnZn ferrites are the dominant soft ferrite in production and use. MnZn ferrites account for approximately 70% of the total soft ferrite yield, and are currently the most popular and active field among soft magnetic materials. Conventional MnZn power ferrite materials are basically used at frequencies of 100kHz, 200mT, or higher frequencies of 1MHz, 50mT, or 3MHz, 80mT.

[0003] CN103482986A discloses a method for sintering low-loss MnZn ferrite material. The method is divided into four temperature change stages, mainly including a) a first temperature rise stage, b) a second temperature rise stage, c) a temperature-holding stage, and d) a temperature-lowering stage. By controlling the temperature and oxygen partial pressure throughout the entire sintering process (heating, holding, and lowering), the loss of the MnZn power ferrite can be reduced. The use of this MnZn power ferrite has the advantages of low sintering temperature and low loss, greatly improving the efficiency of MnZn ferrite elements. However, the MnZn ferrite material obtained by this method has an operating frequency of 100 kHz, a magnetic flux density of 200 mT, and only reduces loss at 100°C.

[0004] CN102219486A discloses a high-temperature, low-loss MnZn power ferrite core and a method for manufacturing the same. The ferrite core contains a main component and an auxiliary component, where the main component is 52 mol% to 53.5 mol% Fe2O3, 37.5 mol% to 42 mol% Mn3O4 as MnO, and 6 mol% to 9 mol% ZnO. The auxiliary component is at least one selected from SiO2, CaCO3, Nb2O5, V2O5, ZrO2, Co2O3, NiO, and Li2CO3. However, the MnZn power ferrite core has an applicable frequency of 100 kHz, a magnetic flux density of 200 mT, and is suitable for temperatures between 120°C and 150°C.

[0005] CN112194482A discloses an ultra-low-loss, wide-temperature-range power MnZn ferrite, its manufacturing method, and its use in the 5G communications field. The wide-temperature-range power MnZn ferrite includes a main crystalline phase and a doped crystalline phase, where the main crystalline phase is MnZn ferrite with a single-phase spinel structure, and the doped crystalline phase includes CaO, SiO2, Nb2O5, ZrO2, Co2O3, and Li2O. However, the wide-temperature-range power MnZn ferrite has an application frequency of 100 kHz and a magnetic flux density of 200 mT.

[0006] CN112456994A discloses a low-temperature sintered, high-frequency, low-loss MnZn soft ferrite and a method for producing the same. The low-temperature sintered, high-frequency, low-loss MnZn soft ferrite contains a main component and an auxiliary component. The main component contains 53.5-56.5 mol% Fe2O3, 3.2-5.5 mol% ZnO, and the remainder Mn3O4. The auxiliary components, based on the total weight of the main component, include 400-1000 ppm nano CaCO3, 200-600 ppm nano V2O5, 100-350 ppm nano Nb2O5, 1500-3500 ppm nano Co2O3, 30-150 ppm nano SiO2, and 100-500 ppm nano CuO. However, the low-temperature sintered, high-frequency, low-loss MnZn soft ferrite has an applicable frequency of 3 MHz and a magnetic flux density of 80 mT, and an applicable frequency of 5 MHz and a magnetic flux density of 50 mT.

[0007] Therefore, the development of a wide temperature range material applicable to the low frequency band of 65 to 75 kHz and a method for preparing the same is of great significance. Summary of the Invention [Problem to be solved by the invention]

[0008] The following is a general summary of the subject matter described in detail herein. This summary does not limit the scope of the claims.

[0009] In order to solve the above technical problems, the present application provides a wide temperature range material applicable to low frequency bands and a preparation method thereof, in which a certain amount of cobalt ferrite and iron ferrite are produced using raw materials Fe2O3, ZnO and Co2O3 in a specific compounding ratio, thereby effectively offsetting the negative magnetocrystalline anisotropy constant K1 in the main phase of MnZn ferrite, and the sintering process is controlled to be carried out with a specific oxygen content, thereby preparing a wide temperature range material applicable to low frequency bands with excellent performance. [Means for solving the problem]

[0010] To achieve this objective, the present application provides the following technical solutions.

[0011] In aspect 1, the present application provides: The composition includes a main compounding component and a sub-component, and the main compounding component is, in terms of mole percentage of each component, Fe2O3: 52.5 to 53.6 mol%, ZnO: 8.2 to 10.5 mol%, and the remaining MnO, The auxiliary components are, in mass % of each component, CaCO3: 0.1 to 0.15 wt%, ZrO2: 0.03 to 0.05 wt%, and Co2O3: 0.33 to 0.43 wt%, with the total weight of the calcined materials of the main components being 100 wt%. To provide a wide temperature range material that is applicable to a low frequency band.

[0012] The wide-temperature-range material described herein, applicable to low-frequency bands, has an applicable frequency band of 65 to 75 kHz and an applicable temperature range of 25 to 120°C. This material achieves the goal of a wide temperature range and low loss by using a specific blending ratio of Fe2O3, ZnO, and Co2O3. The main component is 52.5 to 53.6 mol% Fe2O3, and the secondary component is 0.33 to 0.43 wt% Co2O3, assuming a total weight of 100 wt% of the calcined material of the main component. The cobalt ferrite and iron ferrite formed by these components have positive magnetocrystalline anisotropy constants K1, which cancel out the negative magnetocrystalline anisotropy constant K1 of the main phase, creating the conditions for achieving wide-temperature characteristics within a certain temperature range. However, excessive amounts of Co2O3 and Fe2O3 increase the hysteresis loss and eddy current loss of the material. The reason for this is that too much cobalt ferrite results in a negative magnetocrystalline anisotropy constant K2, which increases hysteresis loss. Too much Fe2O3 also generates excess iron ferrite, which increases eddy current loss. To achieve low loss, attention must be paid to the valley point from the perspective of the main composition. The valley point not only relates to actual applications, but also to the material's magnetostriction coefficient λs and magnetocrystalline anisotropy constant k1, which affect material loss. The present application considers Fe2O3, ZnO, and Co2O3 to be the main substances that affect the valley point. This differs from the conventional view that the valley point is related only to Fe2O3 or that Co2O3 also affects the valley point. The wide-temperature-range material applicable to low-frequency bands according to the present application can have wide-temperature characteristics within the 65-75 kHz range, have low magnetic loss, and better meet the application requirements of laptop chargers, server power supplies, and desktop computer power supplies.

[0013] In a second aspect, the present application provides a method for preparing a wide temperature range material applicable to a low frequency band according to the first aspect, comprising: Step (1) of mixing Fe2O3, ZnO, and MnO of each main composition raw material, and sequentially performing primary sand milling, crushing, and calcination to obtain a calcined material of the main composition component; and (2) mixing the calcined material of the main component with the sub-components CaCO3, ZrO2 and Co2O3, and sequentially carrying out secondary sand milling, spray granulation, ring molding by pressing, and sintering to obtain the wide temperature range material applicable to the low frequency band; The sintering process includes a temperature increase stage and a temperature decrease stage, and the oxygen content at 1200°C in the temperature decrease stage is 2.5 to 3%. A method of preparation is also provided.

[0014] In the present invention, the oxygen content at 1200°C during the cooling phase is strictly controlled to 2.5-3%. This allows for the control of the valley point and, in combination with the main composition, achieves the goal of a wide temperature range and low loss. The principle is that 1200°C is the temperature at which MnZn power ferrite is prone to oxidation. By controlling the oxygen content at this temperature, the amount of cobalt ferrite and iron ferrite produced can be effectively controlled, thereby achieving the goal of a wide temperature range and low loss. However, if the oxygen content is too low, excessive iron ferrite will be produced, reducing the resistivity within the crystal grains and increasing eddy current loss. Similarly, if the oxygen content is too low, excessive cobalt ferrite will be produced, which will result in a large magnetocrystalline anisotropy constant K2 and increasing the hysteresis loss of the material. If the oxygen content is too high, it reduces the amount of iron ferrite and cobalt ferrite produced, which is unfavorable for reducing the overall magnetocrystalline anisotropy constant K1, i.e., it cannot effectively offset the negative magnetocrystalline anisotropy constant K1 value in the main phase of MnZn ferrite, and it is not possible to reduce hysteresis loss. The preparation method of the present application uses raw materials with a specific blending ratio and, in combination with a sintering process at a specific temperature, produces appropriate amounts of iron ferrite, cobalt ferrite, and zinc ferrite, ultimately obtaining a wide temperature range material with excellent performance suitable for low frequency band applications.

[0015] The oxygen content at 1200°C in the temperature-lowering stage according to the present application is 2.5 to 3%, and may be, for example, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, or 3%, but is not limited to the listed values, and other values ​​not listed within the range also apply.

[0016] In one embodiment, the ratio of raw materials to balls to water in the primary sand milling described in step (1) is 1:(6-8):(0.35-0.55), and may be, for example, 1:6:0.35, 1:6.2:0.39, 1:6.5:0.4, 1:7:0.45, 1:7.4:0.45, or 1:8:0.55, but is not limited to the recited values, and other unrecited values ​​within the range also apply.

[0017] In one embodiment, the time for the primary sand milling described in step (1) is 50 to 90 minutes, and may be, for example, 50 minutes, 5 minutes, 60 minutes, 65 minutes, 70 minutes, or 90 minutes, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0018] In one embodiment, the raw material after primary sand milling is agitated prior to the crushing treatment described in step (1).

[0019] In one embodiment, the crushing process is carried out in a rotary kiln.

[0020] In this application, the raw material after the primary sand milling is stirred and then first placed in the preheating tube of the rotary kiln, and after the water is evaporated, it is further placed in the rotary kiln and the raw material is crushed with iron blocks.

[0021] In one embodiment, the temperature of the calcination treatment described in step (1) is 860 to 930°C, and may be, for example, 860°C, 870°C, 890°C, 910°C, 920°C, or 930°C, but is not limited to the listed values, and other values ​​not listed within the range also apply.

[0022] In one embodiment, the ratio of raw materials to balls to water in the secondary sand milling described in step (2) is 1:(6-8):(0.35-0.55), and may be, for example, 1:6:0.35, 1:6.2:0.39, 1:6.5:0.4, 1:7:0.45, 1:7.4:0.45, or 1:8:0.55, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0023] In one embodiment, the time for the secondary sand milling described in step (2) is 120 to 180 minutes, and may be, for example, 120 minutes, 140 minutes, 150 minutes, 170 minutes, 175 minutes, or 180 minutes, but is not limited to the listed values, and other values ​​not listed within the range also apply.

[0024] In one embodiment, the adhesive is added in the secondary sand milling process described in step (2) at a mass concentration of 7.5 to 12%, which may be, for example, 7.5%, 8%, 9%, 10%, 11%, or 12%, but is not limited to the recited values, and other unrecited values ​​within the range also apply.

[0025] In one embodiment, the adhesive is polyvinyl alcohol.

[0026] In one embodiment, the amount of adhesive added accounts for 8 to 10% of the mass of the material after secondary sand milling, and may be, for example, 8%, 8.3%, 9%, 9.5%, 9.8%, or 10%, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0027] In one embodiment, the temperature-raising stage described in step (2) includes an adhesive discharge stage, an intermediate temperature-raising stage, and a densification stage.

[0028] In the present application, the temperature rise step includes an adhesive discharge step, an intermediate temperature rise step, and a densification step, taking into consideration the needs of large-scale production. In large-scale production, the adhesive discharge step is performed at a temperature of 50 to 400°C, and the adhesive cannot be discharged cleanly, so an intermediate temperature rise step of 400 to 930°C is required to further discharge the adhesive.

[0029] In one embodiment, the temperature in the adhesive discharging step is 50 to 400°C, which specifically means that the temperature is increased from 50°C to 400°C.

[0030] In one embodiment, the temperature rise rate during the adhesive discharge step is 1 to 5°C / min, and may be, for example, 1°C / min, 1.5°C / min, 2°C / min, 2.5°C / min, 3°C / min, 4°C / min, or 5°C / min, but is not limited to the listed values, and other values ​​not listed within the numerical range also apply.

[0031] In one embodiment, the temperature of the intermediate heating step is 400 to 930°C, specifically, the temperature is raised from 400°C to 930°C.

[0032] In one embodiment, the heating rate in the intermediate heating stage is 1.5 to 2.5°C / min, and may be, for example, 1.5°C / min, 1.7°C / min, 1.9°C / min, 2°C / min, 2.1°C / min, 2.3°C / min, or 2.5°C / min, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0033] In one embodiment, the temperature in the densification step is 930 to 1300°C, specifically, the temperature is increased from 930°C to 1300°C.

[0034] In one embodiment, the heating rate in the densification stage is 0.5 to 1°C / min, and may be, for example, 0.5°C / min, 0.6°C / min, 0.7°C / min, 0.8°C / min, 0.9°C / min, 0.95°C / min, or 1°C / min, but is not limited to the listed values, and other values ​​not listed within the numerical range also apply.

[0035] In one embodiment, after the temperature-raising step is completed, the temperature is maintained for 4 to 5 hours before the temperature-lowering step begins, and may be, for example, 4 hours, 4.2 hours, 4.5 hours, 4.6 hours, 4.8 hours, or 5 hours, but is not limited to the listed values, and other values ​​not listed within the range also apply.

[0036] In one embodiment, the temperature in the temperature-lowering step is 1300 to 1200°C, which specifically means that the temperature is lowered from 1300°C to 1200°C.

[0037] In one embodiment, the temperature decreasing rate in the temperature decreasing step is 0.8 to 1.5°C / min, and may be, for example, 0.8°C / min, 0.9°C / min, 1°C / min, 1.2°C / min, 1.3°C / min, or 1.5°C / min, but is not limited to the listed values, and other values ​​not listed within the numerical range also apply.

[0038] As a preferred technical solution of the present application, the preparation method comprises: Step (1) of mixing the main raw materials Fe2O3, ZnO, and MnO, followed by primary sand milling for 50-90 minutes with a ratio of raw materials, balls, and water of 1:(6-8):(0.35-0.55), crushing in a rotary kiln, and calcination at a temperature of 860-930°C, to obtain a calcined material of the main raw materials; and (2) mixing the calcined material of the main compound component with the sub-components CaCO3, ZrO2 and Co2O3, and sequentially carrying out secondary sand milling for 120 to 180 min at a ratio of raw materials, balls and water of 1:(6 to 8):(0.35 to 0.55), spray granulation, ring molding by pressing, and sintering to obtain the wide temperature range material applicable to the low frequency band; During the second sand milling process, an adhesive is added at a mass concentration of 7.5 to 12%, the adhesive being polyvinyl alcohol, and the amount of the adhesive added accounts for 8 to 10% of the mass of the material after the second sand milling; The sintering process includes a temperature rise stage and a temperature drop stage, and the temperature rise stage includes an adhesive discharge stage, an intermediate temperature rise stage, and a densification stage. In the adhesive discharge stage, the temperature is 50 to 400°C and the temperature rise rate is 1 to 5°C / min. In the intermediate temperature rise stage, the temperature is 400 to 930°C and the temperature rise rate is 1.5 to 2.5°C / min. In the densification stage, the temperature is 930 to 1300°C and the temperature rise rate is 0.5 to 1°C / min. After the temperature rise stage is completed, the temperature is maintained for 4 to 5 hours before entering the temperature drop stage, and in the temperature drop stage, the temperature is 1300 to 1200°C and the temperature drop rate is 0.8 to 1.5°C / min. The oxygen content at 1200°C in the temperature drop stage is 2.5 to 3%. [Effects of the Invention]

[0039] Compared with the related art, the present application has at least the following beneficial effects:

[0040] (1) The wide temperature range material applicable to low frequency bands according to the present application can be applied to the low frequency band of 65 to 75 kHz, and furthermore, has a wide applicable temperature range and low magnetic loss, and can better meet the application requirements of laptop chargers, server power supplies, desktop computer power supplies, etc.

[0041] (2) The method for preparing a wide temperature range material applicable to the low frequency band according to the present application has a simple operation process, and the oxygen content at 1200°C during the cooling stage can be strictly controlled, allowing the valley point to be controlled. In combination with specific raw materials, the goal of a wide temperature range and low loss can be achieved.

[0042] (3) The wide temperature range material applicable to the low frequency band according to the present application has a loss Pcv of less than 45 kW / m at 25°C under the conditions of 65 kHz and 130 mT within the range of 25 to 120°C. 3 At 60°C, the loss Pcv is less than 45kW / m 3 At 80°C, loss Pcv<45kW / m 3 At 100°C, the loss Pcv is less than 45kW / m 3 At 120°C, the loss Pcv is less than 50kW / m 3 and Loss Pcv under the condition of 75kHz, 150mT is less than 80kW / m at 25℃. 3 At 60°C, loss Pcv<80kW / m 3 At 80℃, loss Pcv<80kW / m 3 At 100°C, the loss Pcv <kW / m 3 At 120°C, the loss Pcv is less than 100kW / m 3 is.

[0043] Other aspects may be understood upon reading and understanding the drawings and detailed description. DETAILED DESCRIPTION OF THE INVENTION

[0044] In order to facilitate understanding of the present application, the present application lists the following examples. Those skilled in the art should understand that the following examples are only for understanding the present application and should not be considered as specifically limiting the present application.

[0045] The present application will be described in more detail below. However, the following examples are merely a simple example of the present application and do not represent or limit the scope of the claims of the present application, and the scope of protection of the present application is based on the claims. [Example]

[0046] This embodiment provides a wide temperature range material applicable to low frequency bands and a preparation method thereof, and the preparation method includes the following steps:

[0047] (1) For each main raw material, 52.85 mol% Fe2O3, 9.6 mol% ZnO, and 37.55 mol% MnO were mixed, and after 60 minutes of primary sand milling with a raw material to ball to water ratio of 1:6.3:0.42, the mixture was placed in a stirring tank, then placed in the preheating tube of a rotary kiln to evaporate the water, and then placed in the rotary kiln. The raw materials were crushed with iron blocks and calcined at a temperature of 930°C to obtain the calcined materials of the main components.

[0048] (2) To the calcined material of the main compound components, 0.1 wt% CaCO3, 0.04 wt% ZrO2, and 0.35 wt% Co2O3 were added based on the total weight of the calcined material of the main compound components, and the material was subjected to secondary sand milling for 128 min with a ratio of raw materials, balls, and water of 1:8:0.35, spray granulation, ring molding by pressing, and sintering in sequence to obtain a wide temperature range material applicable to the low frequency band.

[0049] During the second sand milling process, an adhesive was added at a mass concentration of 9%, which was polyvinyl alcohol, and the amount of the adhesive added accounted for 8.7% of the mass of the material after the second sand milling.

[0050] The sintering process included a heating stage and a cooling stage. The heating stage included an adhesive ejection stage, an intermediate heating stage, and a densification stage. In the adhesive ejection stage, the temperature was increased from 50°C to 400°C at a heating rate of 2.5°C / min. In the intermediate heating stage, the temperature was increased from 400°C to 930°C at a heating rate of 1.5°C / min. In the densification stage, the temperature was increased from 930°C to 1300°C at a heating rate of 0.8°C / min. After the heating stage was completed, the temperature was maintained for 4 hours before entering a cooling stage. In the cooling stage, the temperature was decreased from 1300°C to 1200°C at a cooling rate of 1°C / min. The oxygen content at 1200°C in the cooling stage was 2.6%. [Example]

[0051] This embodiment provides a wide temperature range material applicable to low frequency bands and a preparation method thereof, and the preparation method includes the following steps:

[0052] (1) For each main raw material, 53.2 mol% Fe2O3, 10 mol% ZnO, and 36.8 mol% MnO were mixed, and after 55 minutes of primary sand milling with a raw material / ball / water ratio of 1:8:0.55, the mixture was placed in a mixing tank, then placed in the preheating tube of a rotary kiln to evaporate the water, and then placed in the rotary kiln. The raw materials were crushed with iron blocks and calcined at a temperature of 890°C to obtain the calcined materials of the main components.

[0053] (2) To the calcined material of the main compound components, 0.13 wt% CaCO3, 0.05 wt% ZrO2, and 0.41 wt% Co2O3 were added based on the total weight of the calcined material of the main compound components, and the material was subjected to secondary sand milling for 150 min with a ratio of raw materials, balls, and water of 1:6.6:0.4, spray granulation, ring molding by pressing, and sintering in sequence to obtain a wide temperature range material applicable to the low frequency band.

[0054] During the second sand milling process, an adhesive was added at a mass concentration of 7.5%, which was polyvinyl alcohol, and the amount of the adhesive added accounted for 10% of the mass of the material after the second sand milling.

[0055] The sintering process included a heating stage and a cooling stage. The heating stage included an adhesive ejection stage, an intermediate heating stage, and a densification stage. In the adhesive ejection stage, the temperature was increased from 50°C to 400°C at a heating rate of 1°C / min. In the intermediate heating stage, the temperature was increased from 400°C to 930°C at a heating rate of 2.5°C / min. In the densification stage, the temperature was increased from 930°C to 1300°C at a heating rate of 1°C / min. After the heating stage was completed, the temperature was maintained for 4.2 hours before entering a cooling stage. In the cooling stage, the temperature was decreased from 1300°C to 1200°C at a cooling rate of 1.5°C / min. The oxygen content at 1200°C in the cooling stage was 2.5%. [Example]

[0056] This embodiment provides a wide temperature range material applicable to low frequency bands and a preparation method thereof, and the preparation method includes the following steps:

[0057] (1) For each main raw material, 52.6 mol% Fe2O3, 10 mol% ZnO, and 37.4 mol% MnO were mixed, and after 90 minutes of primary sand milling with a raw material / ball / water ratio of 1:6:0.35, the mixture was placed in a stirring tank, then placed in the preheating tube of a rotary kiln to evaporate the water, and then placed in the rotary kiln. The raw materials were crushed with iron blocks and calcined at a temperature of 860°C to obtain the calcined materials for the main components.

[0058] (2) To the calcined material of the main compound components, 0.15 wt% CaCO3, 0.05 wt% ZrO2, and 0.41 wt% Co2O3 were added based on the total weight of the calcined material of the main compound components, and the mixture was subjected to secondary sand milling for 180 min with a ratio of raw materials, balls, and water of 1:7:0.55, spray granulation, ring molding by pressing, and sintering in sequence to obtain a wide temperature range material applicable to the low frequency band.

[0059] During the second sand milling process, an adhesive was added at a mass concentration of 12%, which was polyvinyl alcohol, and the amount of the adhesive added accounted for 9% of the mass of the material after the second sand milling.

[0060] The sintering process included a heating stage and a cooling stage. The heating stage included an adhesive ejection stage, an intermediate heating stage, and a densification stage. In the adhesive ejection stage, the temperature was increased from 50°C to 400°C at a heating rate of 5°C / min. In the intermediate heating stage, the temperature was increased from 400°C to 930°C at a heating rate of 2.3°C / min. In the densification stage, the temperature was increased from 930°C to 1300°C at a heating rate of 0.5°C / min. After the heating stage was completed, the temperature was maintained for 5 hours before entering a cooling stage. In the cooling stage, the temperature was decreased from 1300°C to 1200°C at a cooling rate of 0.8°C / min. The oxygen content at 1200°C in the cooling stage was 3%.

[0061] [Comparative Example 1] This comparative example provides a wide temperature range material applicable to low frequency bands and a preparation method thereof. The preparation method is the same as that of Example 1 except that the molar percentage of the main raw material in step (1) is 53.9 mol% Fe2O3 and 36.5 mol% MnO.

[0062] Comparative Example 2 This comparative example provides a wide temperature range material applicable to low frequency bands and a preparation method thereof. The preparation method is the same as that of Example 1 except that the molar percentage of the main raw material in step (1) is 52 mol% Fe2O3 and 38.4 mol% MnO.

[0063] Comparative Example 3 This comparative example provides a wide temperature range material applicable to low frequency bands and a preparation method thereof. The preparation method was the same as that of Example 2 except that the molar percentages of ZnO and MnO in the main raw materials in step (1) were 11 mol% and 35.8 mol%, respectively.

[0064] Comparative Example 4 This comparative example provides a wide temperature range material applicable to low frequency bands and a preparation method thereof. The preparation method was the same as that of Example 2 except that the molar percentages of ZnO and MnO in the main raw materials in step (1) were 7.1 mol% and 39.7 mol%, respectively.

[0065] Comparative Example 5 This comparative example provides a wide temperature range material applicable to low frequency bands and a preparation method thereof. The preparation method is the same as that of Example 1 except that the content of the secondary raw material Co2O3 in step (2) is 0.5 wt% based on the total weight of the calcined material of the primary raw material.

[0066] Comparative Example 6 This comparative example provides a wide temperature range material applicable to low frequency bands and a preparation method thereof. The preparation method is the same as that of Example 1 except that the content of the secondary compounding material Co2O3 in step (2) was 0.3 wt% based on the total weight of the calcined material of the primary compounding component.

[0067] Comparative Example 7 This comparative example provides a wide temperature range material applicable to low frequency bands and a preparation method thereof, and the preparation method is the same as that of Example 3 except that the oxygen content at 1200°C during the temperature-reducing stage of the sintering treatment in step (2) is 3.5%.

[0068] [Comparative Example 8] This comparative example provides a wide temperature range material applicable to low frequency bands and a preparation method thereof, and the preparation method is the same as that of Example 3 except that the oxygen content at 1200°C during the temperature-reducing stage of the sintering treatment in step (2) was 0.5%.

[0069] Using a SY8218 measuring instrument, the magnetic loss of the wide temperature range materials applicable to the low frequency band prepared in the above examples and comparative examples was measured at temperatures of 25°C, 60°C, 80°C, 100°C, and 120°C under conditions of 65kHz, 130mT, and 75kHz, 150mT, respectively. The results are shown in Table 1.

[0070] [Table 1]

[0071] From Table 1, the following was found:

[0072] (1) By summarizing Example 1 and Comparative Examples 1 and 2, it was found that if the content of Fe2O3 in the main raw material composition is too high or too low, the loss of the final wide temperature range material applicable to the low frequency band increases.

[0073] (2) By summarizing Example 2 and Comparative Examples 3 and 4, it was found that if the content of the main raw material ZnO is too high or too low, the loss of the final wide temperature range material applicable to the low frequency band increases.

[0074] (3) By summarizing Example 1 and Comparative Examples 5 and 6, it was found that if the content of the secondary raw material Co2O3 is too high or too low, the loss of the final wide temperature range material applicable to the low frequency band increases.

[0075] (4) Summarizing Example 3 and Comparative Examples 7 and 8, it was found that if the oxygen content at 1200°C during the temperature-lowering stage of the sintering process in step (2) is too high, the amount of iron ferrite and cobalt ferrite produced decreases, which is unfavorable for reducing the overall magnetocrystalline anisotropy constant K1 and results in increased loss; if the oxygen content is too low, excessive iron ferrite is produced, which reduces the resistivity inside the crystal grains and increases eddy current loss; and further, excessive cobalt ferrite is produced, which generates a relatively large magnetocrystalline anisotropy constant K2 and increases material loss.

[0076] In summary, the wide temperature range material applicable to low frequency bands and the method for preparing it according to the present application uses raw materials Fe2O3, ZnO, and Co2O3 in a specific compounding ratio to produce a certain amount of cobalt ferrite and iron ferrite, thereby effectively canceling out the negative magnetocrystalline anisotropy constant K1 in the main phase of MnZn ferrite, and controlling the sintering process to have a specific oxygen content, thereby preparing a wide temperature range material applicable to low frequency bands of 65 to 75 kHz, which has a wide applicable temperature range, a low magnetic loss, and can be used in low frequency bands.

[0077] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto, and the applicant declares that it should be understood that any modifications or replacements that a person skilled in the art can easily conceive within the technical scope disclosed in the present application are all included in the scope of protection and disclosure of the present application.

Claims

1. The main compounding component contains a main compounding component and a sub-component, and the main compounding component contains, in mole percent, Fe, ２ O ３ : 52.5 to 53.6 mol%, ZnO: 8.2 to 10.5 mol%, the remainder being MnO; The auxiliary compounding components are, with the total weight of the calcined material of the main compounding components being 100 wt%, CaCO ３ :0.1~0.15wt%, ZrO ２ : 0.03 to 0.05 wt%, and Co ２ O ３ : 0.33 to 0.43 wt%, Wide temperature range material applied to low frequency bands.

2. 2. A method for preparing a wide temperature range material applicable to a low frequency band according to claim 1, comprising: Fe in each main blend raw material ２ O ３ (1) mixing ZnO and MnO, and sequentially performing primary sand milling, crushing, and calcination to obtain a calcined material of the main blend components; The calcined material of the main compounding component and the CaCO ３ , ZrO ２ and Co ２ O ３ and (2) mixing the above-mentioned powder and the resulting mixture, and sequentially carrying out secondary sand milling, spray granulation, ring molding by pressing, and sintering to obtain a wide temperature range material applicable to the low frequency band; The sintering process includes a temperature increase step and a temperature decrease step, and the oxygen content at 1200°C in the temperature decrease step is 2.5 to 3%. Preparation method.

3. The ratio of raw materials, balls, and water in the primary sand milling described in step (1) is 1:(6-8):(0.35-0.55); The preparation method according to claim 2.

4. The time for the primary sand milling described in step (1) is 50 to 90 minutes.

4. The preparation method according to claim 2 or 3.

5. Before the crushing treatment described in step (1), the raw material after the primary sand milling is stirred, Preferably, the crushing treatment is carried out in a rotary kiln. The preparation method according to any one of claims 2 to 4.

6. The temperature of the calcination treatment described in step (1) is 860 to 930 ° C. The preparation method according to any one of claims 2 to 5.

7. The ratio of raw materials, balls, and water in the secondary sand milling described in step (2) is 1:(6-8):(0.35-0.55); The secondary sand milling time is 120 to 180 minutes. The preparation method according to any one of claims 2 to 6.

8. Adding an adhesive at a mass concentration of 7.5 to 12% during the secondary sand milling process described in step (2); Preferably, the adhesive is polyvinyl alcohol; Preferably, the amount of adhesive added accounts for 8-10% of the material mass after secondary sand milling; The preparation method according to any one of claims 2 to 7.

9. The temperature-raising stage described in step (2) includes an adhesive discharge stage, an intermediate temperature-raising stage, and a densification stage; The preparation method according to any one of claims 2 to 8.

10. The temperature of the adhesive discharge step is 50 to 400°C, Preferably, the temperature rise rate in the adhesive discharging step is 1 to 5°C / min.

10. The preparation method according to claim 9.

11. The temperature of the intermediate heating stage is 400 to 930°C, Preferably, the temperature rise rate in the intermediate temperature rise stage is 1.5 to 2.5 ° C. / min.

11. The preparation method according to claim 9 or 10.

12. The temperature of the densification stage is 930 to 1300°C, Preferably, the temperature increase rate in the densification stage is 0.5 to 1 ° C. / min. The preparation method according to any one of claims 9 to 11.

13. After the temperature rising step is completed, the temperature is kept for 4 to 5 hours before the temperature falling step is started. The preparation method according to any one of claims 2 to 12.

14. The temperature in the cooling step is 1300 to 1200°C, Preferably, the temperature decreasing rate in the temperature decreasing step is 0.8 to 1.5 ° C. / min. The preparation method according to any one of claims 2 to 13.

15. Each main compounding raw material Fe ２ O ３ Step (1) of mixing ZnO and MnO, and sequentially performing a primary sand milling process for 50 to 90 minutes with a ratio of raw materials, balls, and water of 1: (6 to 8): (0.35 to 0.55), a crushing process in a rotary kiln, and a calcination process at a temperature of 860 to 930 ° C. to obtain a calcined material of the main blend component; The calcined material of the main compounding component and the CaCO ３ , ZrO ２ and Co ２ O ３ and (2) mixing the above materials, and sequentially carrying out secondary sand milling at a ratio of raw material, balls, and water of 1:(6-8):(0.35-0.55) for 120-180 min, spray granulation, ring molding by pressing, and sintering to obtain a wide temperature range material applicable to the low frequency band; Adding an adhesive with a mass concentration of 7.5-12% during the second sand milling process, the adhesive being polyvinyl alcohol, and the amount of the adhesive added accounts for 8-10% of the mass of the material after the second sand milling; the sintering process includes a temperature rise step and a temperature fall step, the temperature rise step includes an adhesive discharge step, an intermediate temperature rise step, and a densification step, the temperature in the adhesive discharge step is 50 to 400°C and the temperature rise rate is 1 to 5°C / min, the temperature in the intermediate temperature rise step is 400 to 930°C and the temperature rise rate is 1.5 to 2.5°C / min, the temperature in the densification step is 930 to 1300°C and the temperature rise rate is 0.5 to 1°C / min, after the temperature rise step is completed, the temperature is maintained for 4 to 5 hours before entering a temperature fall step, the temperature in the temperature fall step is 1300 to 1200°C and the temperature fall rate is 0.8 to 1.5°C / min, and the oxygen content at 1200°C in the temperature fall step is 2.5 to 3%; The preparation method according to any one of claims 2 to 14.

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