MnZn ferrite material with wide temperature range, low loss and high Bs as well as preparation method and application of MnZn ferrite material
By optimizing the Fe2O3 to MnO ratio and sintering process of MnZn ferrite materials, a material that combines wide temperature range, low loss, and high Bs was prepared, which solved the shortcomings of existing materials in achieving these three properties and improved the efficiency of electronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HENGDIAN GRP DMEGC MAGNETICS CO LTD
- Filing Date
- 2024-11-11
- Publication Date
- 2026-05-12
AI Technical Summary
Existing MnZn ferrite materials cannot simultaneously achieve wide temperature range, low loss, and high saturation flux density (Bs), thus failing to meet the requirements of miniaturization, thinning, and high efficiency in electronic devices.
By rationally controlling the ratio of Fe2O3 to MnO in MnZn ferrite materials and combining it with additives such as CaCO3, Nb2O5 or Co2O3, the sintering process is optimized. In particular, the oxygen content during sintering is controlled to be lower than that during cooling, so as to prepare materials that have both wide temperature range, low loss and high Bs.
It achieves low loss and high Bs performance over a wide temperature range, improving the working efficiency of electronic components and is suitable for micro motors, filters and sensors.
Smart Images
Figure BDA0005127987970000121
Abstract
Description
Technical Field
[0001] This invention belongs to the field of ferrite material technology, and relates to a MnZn ferrite material, and more particularly to a MnZn ferrite material that combines wide temperature range, low loss and high Bs, as well as its preparation method and application. Background Technology
[0002] Currently, electronic devices are constantly evolving towards miniaturization, thinner designs, and higher efficiency. This necessitates magnetic materials with higher saturation flux density (Bs) to achieve high power density in magnetic devices, while simultaneously requiring lower losses to achieve high efficiency. Especially in recent years, electronic devices have increasingly focused on efficiency under light loads, which, in relation to magnetic materials, necessitates a balance between wide temperature range, low loss, and high Bs characteristics.
[0003] However, existing MnZn ferrite materials cannot adequately balance the above three properties: if Bs is increased, losses will generally increase; or if losses are reduced, Bs will generally decrease; or they simply do not possess wide temperature range characteristics.
[0004] For example, the MnZn ferrite material disclosed in CN116283263A has a Bs of 409 mT at 100℃, and only a single valley point at 100℃, indicating it is not a wide-temperature material; the MnZn ferrite material disclosed in CN101429016A has a Bs of 460 mT at 100℃ (1200 A / m at 10 kHz), and a loss of 367-385 kW / m under the condition of 200 mT at 100 kHz. 3 Furthermore, it only has a single valley point at 100℃, and is therefore not a wide-temperature material; the ferrite sintered body disclosed in CN1890197A has a Bs of 490mT (1000A / m) at 100℃, but its loss is as high as 1089kW / m under the condition of 50kHz and 150mT. 3 Furthermore, it has only a single valley point at 100℃, and is not a wide-temperature material.
[0005] Therefore, how to provide a MnZn ferrite material and its preparation method that takes into account both wide temperature range, low loss and high Bs, so as to better meet the needs of energy conservation, emission reduction and improving the working efficiency of electronic components, has become an urgent problem to be solved by those skilled in the art. Summary of the Invention
[0006] To address the shortcomings of existing technologies, the present invention aims to provide a MnZn ferrite material that combines wide temperature range, low loss, and high Bs, along with its preparation method and applications. By rationally controlling the ratio of Fe2O3 to MnO and the sintering process in the MnZn ferrite material, the single valley point of traditional MnZn ferrite materials is changed, ultimately resulting in a MnZn ferrite material that combines wide temperature range, low loss, and high Bs. This better meets the needs of energy conservation, emission reduction, and improved efficiency of electronic components, and is conducive to large-scale application.
[0007] To achieve this objective, the present invention adopts the following technical solution:
[0008] In a first aspect, the present invention provides a MnZn ferrite material that combines wide temperature range, low loss, and high Bs, wherein the MnZn ferrite material is composed of a main component and additives.
[0009] The principal component comprises the following components in molar percentage:
[0010] Fe2O3 52.85-53.15 mol%.
[0011] MnO 37.40-37.90 mol%.
[0012] The balance is ZnO.
[0013] The additives include any one or a combination of at least two of CaCO3, Nb2O5, or Co2O3. Typical but non-limiting combinations include combinations of CaCO3 and Nb2O5, Nb2O5 and Co2O3, CaCO3 and Co2O3, or combinations of CaCO3, Nb2O5, and Co2O3.
[0014] In this invention, the Fe2O3 content is 52.85-53.15 mol%, for example, it can be 52.85 mol%, 52.90 mol%, 52.95 mol%, 53.00 mol%, 53.05 mol%, 53.10 mol%, or 53.15 mol%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0015] Specifically, when the Fe2O3 content is below 52.85 mol%, the saturation magnetic flux density Bs of the MnZn ferrite material decreases significantly; when the Fe2O3 content is above 53.15 mol%, the eddy current loss of the MnZn ferrite material increases significantly.
[0016] In this invention, the content of MnO is 37.40-37.90 mol%, for example, it can be 37.40 mol%, 37.45 mol%, 37.50 mol%, 37.55 mol%, 37.60 mol%, 37.65 mol%, 37.70 mol%, 37.75 mol%, 37.80 mol%, 37.85 mol%, or 37.90 mol%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0017] Specifically, when the MnO content is below 37.40 mol%, the eddy current loss of MnZn ferrite material increases significantly, and the magnetocrystalline anisotropy constant K1 is also increased. When the MnO content is above 37.90 mol%, the hysteresis coefficient λs increases significantly, thereby increasing the internal stress of MnZn ferrite material, which is not conducive to reducing losses.
[0018] This invention achieves a balance between low loss and high Bs by rationally controlling the ratio of Fe2O3 to MnO in MnZn ferrite materials, thereby making the magnetocrystalline anisotropy constant K1 and the hysteresis coefficient λs approach zero. This lays the foundation for reducing the eddy current loss of MnZn ferrite materials and significantly improves the saturation magnetic flux density Bs.
[0019] Preferably, the ZnO content in the main component is 8.95-9.75 mol%, for example, it can be 8.95 mol%, 9.00 mol%, 9.05 mol%, 9.10 mol%, 9.15 mol%, 9.20 mol%, 9.25 mol%, 9.30 mol%, 9.35 mol%, 9.40 mol%, 9.45 mol%, 9.50 mol%, 9.55 mol%, 9.60 mol%, 9.65 mol%, 9.70 mol%, or 9.75 mol%, but is not limited to the listed values; other unlisted values within this range are also applicable.
[0020] Preferably, the total weight of the main components is used as the calculation basis, and the content of CaCO3 in the additive is 0.05-0.15%, for example, it can be 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14% or 0.15%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0021] Preferably, the total weight of the main components is used as the calculation basis, and the Nb2O5 content in the additive is 0.025-0.045%, for example, it can be 0.025%, 0.026%, 0.028%, 0.030%, 0.032%, 0.034%, 0.036%, 0.038%, 0.040%, 0.042%, 0.044% or 0.045%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0022] Preferably, the total weight of the main components is used as the calculation basis, and the content of Co2O3 in the additive is 0.48-0.55%, for example, it can be 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54% or 0.55%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0023] In a second aspect, the present invention provides a method for preparing the MnZn ferrite material as described in the first aspect, the method comprising the following steps:
[0024] (1) Fe2O3, MnO and ZnO are mixed and milled once to obtain the first abrasive;
[0025] (2) Mix the glue and the first abrasive obtained in step (1) and spray granulation to obtain the first intermediate material;
[0026] (3) The first intermediate material obtained in step (2) is pre-fired to obtain pre-fired material;
[0027] (4) Mix the additives and the pre-burned material obtained in step (3) and perform secondary sand milling to obtain the second abrasive.
[0028] (5) Mix the glue and the second abrasive obtained in step (4) and spray granulation to obtain the second intermediate material;
[0029] (6) Press the second intermediate material obtained in step (5) into a standard ring, sinter it and then cool it to obtain MnZn ferrite material.
[0030] In step (6), the oxygen content during sintering is less than the oxygen content during cooling.
[0031] The preparation method provided by this invention achieves the purpose of increasing sintering density and saturation magnetic flux density Bs and reducing eddy current loss by limiting the oxygen content during sintering to be lower than that during cooling, i.e., low oxygen content in the high-temperature section and high oxygen content in the low-temperature section. At the same time, it controls the amount of cobalt ferrite generated, further achieving the goal of wide temperature range. Finally, it produces MnZn ferrite material that combines wide temperature range, low loss and high Bs, which better meets the needs of energy conservation, emission reduction and improving the working efficiency of electronic components, and is conducive to large-scale promotion and application.
[0032] Preferably, the mass ratio of material balls to water in the first grinding step (1) is 1:(4-8):(0.5-0.6), for example, it can be 1:4:0.5, 1:5:0.5, 1:6:0.55, 1:7:0.6 or 1:8:0.6, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0033] In this invention, the material-to-water mass ratio specifically refers to the mass ratio between the grinding material, the grinding balls, and water, and the grinding material in this primary grinding process is a mixture of Fe2O3, MnO, and ZnO.
[0034] Preferably, the time for one sanding in step (1) is 60-80 minutes, for example, it can be 60 minutes, 62 minutes, 64 minutes, 66 minutes, 68 minutes, 70 minutes, 72 minutes, 74 minutes, 76 minutes, 78 minutes or 80 minutes, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0035] Preferably, the adhesive in step (2) comprises polyvinyl alcohol, i.e., PVA.
[0036] Preferably, the concentration of the adhesive in step (2) is 7-8 wt%, for example, it can be 7 wt%, 7.1 wt%, 7.2 wt%, 7.3 wt%, 7.4 wt%, 7.5 wt%, 7.6 wt%, 7.7 wt%, 7.8 wt%, 7.9 wt%, or 8 wt%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0037] Preferably, the weight of the first abrasive is used as the calculation basis, and the mixing amount of the adhesive in step (2) is 8-12%, for example, it can be 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5% or 12%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0038] Preferably, the preheating temperature in step (3) is 900-920℃, for example, it can be 900℃, 902℃, 904℃, 906℃, 908℃, 910℃, 912℃, 914℃, 916℃, 918℃ or 920℃, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0039] Preferably, the preheating time in step (3) is 60-180 min, for example, it can be 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min or 180 min, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0040] Preferably, the pre-firing in step (3) is carried out in a rotary kiln.
[0041] Preferably, the mass ratio of material balls to water in the secondary sand milling in step (4) is 1:(4-8):(0.4-0.5), for example, it can be 1:4:0.4, 1:5:0.4, 1:6:0.45, 1:7:0.5 or 1:8:0.5, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0042] In this invention, the mass ratio of grinding balls to water specifically refers to the mass ratio between the grinding material, the grinding balls, and water, and the grinding material in the secondary grinding is a mixture of pre-burned material and additives.
[0043] Preferably, the time for one sanding in step (4) is 60-80 min, for example, it can be 60 min, 62 min, 64 min, 66 min, 68 min, 70 min, 72 min, 74 min, 76 min, 78 min or 80 min, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0044] Preferably, the adhesive in step (5) comprises polyvinyl alcohol, i.e., PVA.
[0045] Preferably, the concentration of the adhesive in step (5) is 7-8 wt%, for example, it can be 7 wt%, 7.1 wt%, 7.2 wt%, 7.3 wt%, 7.4 wt%, 7.5 wt%, 7.6 wt%, 7.7 wt%, 7.8 wt%, 7.9 wt%, or 8 wt%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0046] Preferably, the weight of the second abrasive is used as the calculation basis, and the mixing amount of the adhesive in step (5) is 8-12%, for example, it can be 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5% or 12%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0047] Preferably, the sintering temperature in step (6) is 1290-1300℃, for example, it can be 1290℃, 1291℃, 1292℃, 1293℃, 1294℃, 1295℃, 1296℃, 1297℃, 1298℃, 1299℃ or 1300℃, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0048] Preferably, the sintering time in step (6) is 30-40 min, for example, it can be 30 min, 31 min, 32 min, 33 min, 34 min, 35 min, 36 min, 37 min, 38 min, 39 min or 40 min, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0049] Preferably, when the sintering time does not exceed 30 minutes, the oxygen content is 0-1%, for example, it can be 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%; when the sintering time exceeds 30 minutes, the oxygen content is 3-5%, for example, it can be 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, or 5%, but it is not limited to the listed values, and other unlisted values within this range are also applicable.
[0050] Preferably, the sintering in step (6) is carried out in a bell furnace.
[0051] Preferably, when the cooling temperature is below 1150°C, the oxygen content is 1-1.5%, for example, it can be 1%, 1.05%, 1.1%, 1.15%, 1.2%, 1.25%, 1.3%, 1.35%, 1.4%, 1.45%, or 1.5%, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0052] As a preferred embodiment of the second aspect of the present invention, the preparation method includes the following steps:
[0053] (1) Mix Fe2O3, MnO and ZnO and perform a single sand milling for 60-80 min, and control the mass ratio of material balls to water to be 1:(4-8):(0.5-0.6) to obtain the first abrasive;
[0054] (2) A mixture of polyvinyl alcohol adhesive with a concentration of 7-8 wt% and the first abrasive obtained in step (1) is spray-granulated to obtain a first intermediate material; the mixing amount of the polyvinyl alcohol adhesive is 8-12% based on the weight of the first abrasive.
[0055] (3) Place the first intermediate material obtained in step (2) into a rotary kiln and pre-fire it at 900-920℃ for 60-180 minutes to obtain pre-fired material;
[0056] (4) Mix the additives and the pre-calcined material obtained in step (3) and perform a second sand milling for 60-80 minutes, and control the mass ratio of material balls to water to be 1:(4-8):(0.4-0.5) to obtain the second abrasive.
[0057] (5) Mix a polyvinyl alcohol adhesive with a concentration of 7-8 wt% and the second abrasive obtained in step (4) and spray granulate to obtain a second intermediate material; the mixing amount of the polyvinyl alcohol adhesive is 8-12% based on the weight of the second abrasive.
[0058] (6) Press the second intermediate material obtained in step (5) into a standard ring and place it in a bell furnace. Sinter at 1290-1300℃ for 30-40 min and then cool down to obtain MnZn ferrite material.
[0059] In step (6), the oxygen content during sintering is less than the oxygen content during cooling; when the sintering time does not exceed 30 minutes, the oxygen content is 0-1%; when the sintering time exceeds 30 minutes, the oxygen content is 3-5%; when the cooling temperature is below 1150℃, the oxygen content is 1-1.5%.
[0060] Thirdly, the present invention provides an application of the MnZn ferrite material as described in the first aspect, wherein the MnZn ferrite material is used to manufacture micro motors, filters or sensors.
[0061] The numerical range described in this invention includes not only the point values listed above, but also any point values within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values included in the range.
[0062] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0063] (1) By rationally controlling the ratio of Fe2O3 to MnO in MnZn ferrite material, the magnetocrystalline anisotropy constant K1 and the hysteresis coefficient λs approach zero, thus laying the foundation for reducing the eddy current loss of MnZn ferrite material, while significantly improving the saturation magnetic flux density Bs, and finally taking into account both low loss and high Bs performance.
[0064] (2) The preparation method provided by the present invention achieves the purpose of increasing sintering density and saturation magnetic flux density Bs and reducing eddy current loss by limiting the oxygen content during sintering to be less than that during cooling, i.e., low oxygen content in the high temperature section and high oxygen content in the low temperature section. At the same time, it controls the amount of cobalt ferrite generated, further achieving the purpose of wide temperature range. Finally, a MnZn ferrite material with wide temperature range, low loss and high Bs is obtained, which better meets the needs of energy saving and emission reduction and improving the working efficiency of electronic components, and is conducive to large-scale promotion and application. Detailed Implementation
[0065] The technical solution of the present invention will be further illustrated below through specific embodiments.
[0066] Example 1
[0067] This embodiment provides a MnZn ferrite material that combines wide temperature range, low loss, and high Bs, and its preparation method. The preparation method includes the following steps:
[0068] (1) Mix 52.85 mol% Fe2O3, 37.4 mol% MnO and 9.75 mol% ZnO and perform a single sand milling for 70 min, and control the mass ratio of material balls to water to be 1:6:0.55 to obtain the first abrasive;
[0069] (2) A mixture of 7.5 wt% polyvinyl alcohol adhesive and the first abrasive obtained in step (1) is spray-granulated to obtain a first intermediate material; the amount of polyvinyl alcohol adhesive is 10% based on the weight of the first abrasive.
[0070] (3) Place the first intermediate material obtained in step (2) into a rotary kiln and pre-fire it at 910°C for 100 minutes to obtain the pre-fired material.
[0071] (4) Using the total weight of the pre-burned material obtained in step (3) as the calculation basis, mix 0.05% CaCO3, 0.035% Nb2O5, 0.48% Co2O3 and the pre-burned material and perform secondary sand milling for 70 min, and control the mass ratio of material balls to water to be 1:6:0.45 to obtain the second abrasive.
[0072] (5) Mix a 7.5 wt% polyvinyl alcohol adhesive and the second abrasive obtained in step (4) and spray granulate to obtain a second intermediate material; the amount of polyvinyl alcohol adhesive mixed is 10% based on the weight of the second abrasive.
[0073] (6) The second intermediate material obtained in step (5) is pressed into a standard ring and placed in a bell furnace. After sintering at 1290°C for 30 minutes, the temperature is lowered to obtain MnZn ferrite material.
[0074] In step (6), the oxygen content during sintering is less than the oxygen content during cooling; when the sintering time does not exceed 30 minutes, the oxygen content is 0%; when the sintering time exceeds 30 minutes, the oxygen content is 5%; when the cooling temperature is below 1150℃, the oxygen content is 1.5%.
[0075] Example 2
[0076] This embodiment provides a MnZn ferrite material that combines wide temperature range, low loss, and high Bs, and its preparation method. The preparation method includes the following steps:
[0077] (1) Mix 53 mol% Fe2O3, 37.4 mol% MnO and 9.6 mol% ZnO and perform a single sand milling for 70 min, and control the mass ratio of material balls to water to be 1:6:0.55 to obtain the first abrasive;
[0078] (2) A mixture of 7.5 wt% polyvinyl alcohol adhesive and the first abrasive obtained in step (1) is spray-granulated to obtain a first intermediate material; the amount of polyvinyl alcohol adhesive is 10% based on the weight of the first abrasive.
[0079] (3) Place the first intermediate material obtained in step (2) into a rotary kiln and pre-fire it at 910°C for 120 minutes to obtain pre-fired material;
[0080] (4) Using the total weight of the pre-burned material obtained in step (3) as the calculation basis, mix 0.15% CaCO3, 0.04% Nb2O5, 0.5% Co2O3 and the pre-burned material and perform secondary sand milling for 70 min, and control the mass ratio of material ball to water to be 1:6:0.45 to obtain the second abrasive.
[0081] (5) Mix a 7.5 wt% polyvinyl alcohol adhesive and the second abrasive obtained in step (4) and spray granulate to obtain a second intermediate material; the amount of polyvinyl alcohol adhesive mixed is 10% based on the weight of the second abrasive.
[0082] (6) The second intermediate material obtained in step (5) is pressed into a standard ring and placed in a bell furnace. After sintering at 1290°C for 30 minutes, the temperature is lowered to obtain MnZn ferrite material.
[0083] In step (6), the oxygen content during sintering is less than the oxygen content during cooling; when the sintering time does not exceed 30 minutes, the oxygen content is 0%; when the sintering time exceeds 30 minutes, the oxygen content is 5%; when the cooling temperature is below 1150℃, the oxygen content is 1.5%.
[0084] Example 3
[0085] This embodiment provides a MnZn ferrite material that combines wide temperature range, low loss, and high Bs, and its preparation method. The preparation method includes the following steps:
[0086] (1) Mix 52.95 mol% Fe2O3, 37.8 mol% MnO and 9.25 mol% ZnO and perform a single sand milling for 70 min, and control the mass ratio of material balls to water to be 1:6:0.55 to obtain the first abrasive;
[0087] (2) A mixture of 7.5 wt% polyvinyl alcohol adhesive and the first abrasive obtained in step (1) is spray-granulated to obtain a first intermediate material; the amount of polyvinyl alcohol adhesive is 10% based on the weight of the first abrasive.
[0088] (3) Place the first intermediate material obtained in step (2) into a rotary kiln and pre-fire it at 910°C for 180 min to obtain pre-fired material;
[0089] (4) Using the total weight of the pre-burned material obtained in step (3) as the calculation basis, mix 0.15% CaCO3, 0.045% Nb2O5, 0.53% Co2O3 and the pre-burned material and perform secondary sand milling for 70 minutes, and control the mass ratio of material balls to water to be 1:6:0.45 to obtain the second abrasive.
[0090] (5) Mix a 7.5 wt% polyvinyl alcohol adhesive and the second abrasive obtained in step (4) and spray granulate to obtain a second intermediate material; the amount of polyvinyl alcohol adhesive mixed is 10% based on the weight of the second abrasive.
[0091] (6) The second intermediate material obtained in step (5) is pressed into a standard ring and placed in a bell furnace. After sintering at 1290°C for 30 minutes, the temperature is lowered to obtain MnZn ferrite material.
[0092] In step (6), the oxygen content during sintering is less than the oxygen content during cooling; when the sintering time does not exceed 30 minutes, the oxygen content is 0%; when the sintering time exceeds 30 minutes, the oxygen content is 5%; when the cooling temperature is below 1150℃, the oxygen content is 1.5%.
[0093] Comparative Example 1
[0094] This comparative example provides a MnZn ferrite material and its preparation method. The preparation method is the same as in Example 1 except that the mixing amount of Fe2O3 in step (1) is changed to 52.35 mol% and the mixing amount of MnO is changed to 37.9 mol%. Therefore, it will not be described in detail here.
[0095] Comparative Example 2
[0096] This comparative example provides a MnZn ferrite material and its preparation method. The preparation method is the same as that in Example 2 except that the amount of Co2O3 in step (4) is changed to 0.4%. Therefore, it will not be described in detail here.
[0097] Comparative Example 3
[0098] This comparative example provides a MnZn ferrite material and its preparation method. The preparation method is the same as that in Example 3 except that when the cooling temperature in step (6) is lower than 1150℃, the oxygen content is changed to 0.1%. Therefore, it will not be described in detail here.
[0099] The performance test results of the MnZn ferrite materials obtained in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 below.
[0100] Table 1
[0101]
[0102] As can be seen, by rationally controlling the ratio of Fe2O3 to MnO in the MnZn ferrite material, the present invention makes the magnetocrystalline anisotropy constant K1 and the hysteresis coefficient λs approach zero, thereby laying the foundation for reducing the eddy current loss of the MnZn ferrite material, while significantly improving the saturation magnetic flux density Bs, and ultimately achieving both low loss and high Bs performance.
[0103] Furthermore, the preparation method provided by this invention achieves the purpose of increasing sintering density and saturation magnetic flux density Bs and reducing eddy current loss by limiting the oxygen content during sintering to be lower than that during cooling, i.e., low oxygen content in the high-temperature section and high oxygen content in the low-temperature section. At the same time, it controls the amount of cobalt ferrite generated, further achieving the goal of wide temperature range. Finally, it produces MnZn ferrite material that combines wide temperature range, low loss and high Bs, which better meets the needs of energy conservation, emission reduction and improving the working efficiency of electronic components, and is conducive to large-scale promotion and application.
[0104] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are 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 within the protection scope of the present invention.
Claims
1. A MnZn ferrite material that combines wide temperature range, low loss, and high Bs, characterized in that, The MnZn ferrite material is composed of a main component and additives; The principal component comprises the following components in molar percentage: Fe2O3 52.85-53.15 mol%. MnO 37.40-37.90 mol%. The balance is ZnO; The additives include any one or a combination of at least two of CaCO3, Nb2O5, or Co2O3.
2. The MnZn ferrite material according to claim 1, characterized in that, The ZnO content in the main component is 8.95-9.75 mol% (molar percentage).
3. The MnZn ferrite material according to claim 1 or 2, characterized in that, Based on the total weight of the main components, the CaCO3 content in the additive is 0.05-0.15%. Preferably, the total weight of the main components is used as the calculation basis, and the Nb2O5 content in the additive is 0.025-0.045%. Preferably, the total weight of the main components is used as the calculation basis, and the content of Co2O3 in the additive is 0.48-0.55%.
4. A method for preparing the MnZn ferrite material as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) Fe2O3, MnO and ZnO are mixed and milled once to obtain the first abrasive; (2) Mix the glue and the first abrasive obtained in step (1) and spray granulation to obtain the first intermediate material; (3) The first intermediate material obtained in step (2) is pre-fired to obtain pre-fired material; (4) Mix the additives and the pre-burned material obtained in step (3) and perform secondary sand milling to obtain the second abrasive. (5) Mix the glue and the second abrasive obtained in step (4) and spray granulation to obtain the second intermediate material; (6) Press the second intermediate material obtained in step (5) into a standard ring, sinter it and then cool it to obtain MnZn ferrite material; In step (6), the oxygen content during sintering is less than the oxygen content during cooling.
5. The preparation method according to claim 4, characterized in that, The mass ratio of material balls to water in the first sand milling in step (1) is 1:(4-8):(0.5-0.6); Preferably, the time for one sanding in step (1) is 60-80 minutes; Preferably, the adhesive in step (2) comprises polyvinyl alcohol; Preferably, the concentration of the adhesive in step (2) is 7-8 wt%; Preferably, the amount of adhesive mixed in step (2) is 8-12%, with the weight of the first abrasive as the calculation basis.
6. The preparation method according to claim 4 or 5, characterized in that, The pre-firing temperature in step (3) is 900-920℃; Preferably, the pre-firing time in step (3) is 60-180 min; Preferably, the pre-firing in step (3) is carried out in a rotary kiln.
7. The preparation method according to any one of claims 4-6, characterized in that, The mass ratio of material balls to water in the secondary sand milling in step (4) is 1:(4-8):(0.4-0.5); Preferably, the time for one sanding in step (4) is 60-80 minutes; Preferably, the adhesive in step (5) comprises polyvinyl alcohol; Preferably, the concentration of the adhesive in step (5) is 7-8 wt%; Preferably, the amount of adhesive mixed in step (5) is 8-12%, with the weight of the second abrasive as the calculation basis.
8. The preparation method according to any one of claims 4-7, characterized in that, The sintering temperature in step (6) is 1290-1300℃; Preferably, the sintering time in step (6) is 30-40 min; Preferably, when the sintering time does not exceed 30 minutes, the oxygen content is 0-1%; when the sintering time exceeds 30 minutes, the oxygen content is 3-5%. Preferably, the sintering in step (6) is carried out in a bell-shaped furnace; Preferably, when the cooling temperature is below 1150°C, the oxygen content is 1-1.5%.
9. The preparation method according to any one of claims 4-8, characterized in that, The preparation method includes the following steps: (1) Mix Fe2O3, MnO and ZnO and perform a single sand milling for 60-80 min, and control the mass ratio of material balls to water to be 1:(4-8):(0.5-0.6) to obtain the first abrasive; (2) A mixture of polyvinyl alcohol adhesive with a concentration of 7-8 wt% and the first abrasive obtained in step (1) is spray-granulated to obtain a first intermediate material; the mixing amount of the polyvinyl alcohol adhesive is 8-12% based on the weight of the first abrasive. (3) Place the first intermediate material obtained in step (2) into a rotary kiln and pre-fire it at 900-920℃ for 60-180 minutes to obtain pre-fired material; (4) Mix the additives and the pre-calcined material obtained in step (3) and perform a second sand milling for 60-80 minutes, and control the mass ratio of material balls to water to be 1:(4-8):(0.4-0.5) to obtain the second abrasive. (5) Mix a polyvinyl alcohol adhesive with a concentration of 7-8 wt% and the second abrasive obtained in step (4) and spray granulate to obtain a second intermediate material; the mixing amount of the polyvinyl alcohol adhesive is 8-12% based on the weight of the second abrasive. (6) Press the second intermediate material obtained in step (5) into a standard ring and place it in a bell furnace. Sinter at 1290-1300℃ for 30-40 min and then cool down to obtain MnZn ferrite material. In step (6), the oxygen content during sintering is less than the oxygen content during cooling; when the sintering time does not exceed 30 minutes, the oxygen content is 0-1%; when the sintering time exceeds 30 minutes, the oxygen content is 3-5%; when the cooling temperature is below 1150℃, the oxygen content is 1-1.5%.
10. An application of the MnZn ferrite material as described in any one of claims 1-3, characterized in that, The MnZn ferrite material is used to manufacture micro motors, filters, or sensors.