A medium-high frequency low-power consumption mnzn ferrite material, a preparation method and application thereof

Abstract

This invention provides a medium-to-high frequency, low-power MnZn ferrite material, its preparation method, and its applications, belonging to the field of ferrite materials. The raw materials for preparing the medium-to-high frequency, low-power MnZn ferrite material of this invention include main materials, auxiliary materials, and a binder: By molar fraction, the main materials include 50-54.5% Fe2O3, 5.0-9.0% ZnO, 0.01-0.05% B2O3, 0.5-1% Ta2O5, and the balance Mn3O4; Based on the mass fraction of the main materials as 100%, the auxiliary materials include 0.03-0.2% CaO, 0.005-0.03% SiO2, 0.01-0.2% Nb2O5, 0.1-0.6% Co2O3, 0.05-0.3% SnO2, and 0.01-0.2% ZrO2. The MnZn ferrite material of the present invention has low power consumption at 300K-1MHz.

Description

Technical Field

[0001] This invention relates to the field of ferrite materials, specifically to a medium-high frequency, low-power MnZn ferrite material, its preparation method, and its application. Background Technology

[0002] The rapid development of third-generation semiconductor technology has driven the development of fields such as artificial intelligence and new energy towards higher frequencies (300K-1MHz). MnZn ferrite, as a core component of magnetic elements in semiconductors, has high resistivity, resulting in high-frequency and low-loss characteristics. It also has high permeability and high saturation magnetic flux density, making it widely used and currently the most widely used soft magnetic ferrite.

[0003] However, the power consumption of soft magnetic ferrites in the existing technology is still relatively high at 300K-1MHz. Summary of the Invention

[0004] This invention provides a medium-to-high frequency, low-power MnZn ferrite material, its preparation method, and its application. The medium-to-high frequency, low-power MnZn ferrite material of this invention has low power consumption at 300K-1MHz.

[0005] This invention provides a medium-high frequency, low-power MnZn ferrite material. The raw materials for preparing the medium-high frequency, low-power MnZn ferrite material include main materials, auxiliary materials, and binders: The main material comprises, by mole fraction, 50-54.5% Fe2O3, 5.0-9.0% ZnO, 0.01-0.05% B2O3, 0.5-1% Ta2O5, and the balance Mn3O4. Based on the main material's mass fraction of 100%, the auxiliary materials include CaO 0.03~0.2%, SiO2 0.005~0.03%, Nb2O5 0.01~0.2%, Co2O3 0.1~0.6%, SnO2 0.05~0.3%, and ZrO2 0.01~0.2%.

[0006] Preferably, the adhesive comprises polyvinyl alcohol.

[0007] Preferably, the mass of the adhesive is 0.05 to 0.4% of the total mass of the main material and auxiliary materials.

[0008] This invention also provides a method for preparing the medium-high frequency, low-power MnZn ferrite material described in the above technical solution, comprising the following steps: The main ingredients are mixed and then pre-fired to obtain pre-fired main ingredients; The pre-fired main material is mixed with auxiliary materials and binder and sintered to obtain the medium-high frequency low power consumption MnZn ferrite material.

[0009] Preferably, the mixing of the main ingredients includes: initially mixing the main ingredients and then mixing them with water, followed by drying.

[0010] Preferably, the pre-firing temperature is 840~950℃ and the time is 0.5~3h.

[0011] Preferably, when mixing the pre-fired main material with the auxiliary materials and binder, the process includes: The pre-fired main and auxiliary materials are mixed with water and then ball-milled. The resulting slurry is then dried and mixed with a binder. The resulting mixture is then spray-granulated and the resulting particles are then pressed into shape.

[0012] Preferably, the sintering includes a first sintering, a second sintering, and a third sintering performed sequentially; The first sintering temperature is 700℃, and the heating rate to the first sintering temperature is 1℃ / min; during the heating process to the first sintering temperature, the oxygen content is 21%. The second sintering temperature is 1100℃, and the heating rate to the second sintering temperature is 0.33℃ / min; during the heating process to the second sintering temperature, the oxygen content is 0%. The third sintering temperature is 1180~1320℃, the holding time is 6~24h, and the third sintering is carried out in air; the heating rate to the third sintering temperature is 1.33~2.5℃ / min; during the heating to the third sintering temperature, the oxygen content is 0~2.5%.

[0013] Preferably, after sintering, the process further includes: cooling; The cooling includes a first cooling, a second cooling, and a third cooling performed sequentially. The first cooling temperature is 1000℃, and the cooling rate to the first cooling temperature is 1~2℃ / min; during the cooling process to the first cooling temperature, an equilibrium atmosphere is maintained. The second cooling temperature is 950℃, and the cooling rate to the second cooling temperature is 1~2℃ / min; during the cooling process to the first cooling temperature, the oxygen content is 0.09~0.15%; The third cooling temperature is room temperature, and the cooling rate to the third cooling temperature is 1~9℃ / min; during the cooling process to the first cooling temperature, the oxygen content is below 70ppm.

[0014] The present invention also provides the application of the medium-high frequency low power consumption MnZn ferrite material described in the above technical solution or the medium-high frequency low power consumption MnZn ferrite material prepared by the preparation method described in the above technical solution in semiconductors.

[0015] The present invention adds flux B2O3 to the main material, which allows it to react fully with Fe2O3, ZnO and Mn3O4 during pre-calcination, thereby reducing the sintering temperature. Since the sintering temperature is reduced, the porosity is likely to increase. At this time, the addition of flux can promote grain boundary melting. After the grain boundary melts, it promotes the discharge of pores. At the same time, Ta2O5, which is easy to exist at the grain boundary, will squeeze the pore positions, thereby achieving the characteristics of low porosity and small grain size, and reducing the power consumption of the material at 300K-1MHz.

[0016] Furthermore, the increase in grain size is directly proportional to the sintering temperature. This is mainly because grain growth requires the sintering temperature to overcome the interfacial energy. Therefore, when sintering is maintained at a low temperature (1180~1320℃) for a long time, the increase in grain size is not significant; only small grains gradually become uniform. Simultaneously, air sintering with a high oxygen content allows for the growth of more Fe... 2+ Oxidized to Fe 3 + This makes it difficult for electrons to jump, resulting in smaller core grain size and more grain boundaries after sintering, which improves resistivity, reduces eddy current loss, and further achieves ultra-low loss over a wide temperature range of 300K-1MHz.

[0017] Furthermore, sintering with high oxygen content at a temperature of 1000~950℃, with the help of the antiferrite reaction of MnFe2O4, forms a high resistance layer, reducing eddy current loss. Detailed Implementation

[0018] This invention provides a medium-high frequency, low-power MnZn ferrite material. The raw materials for preparing the medium-high frequency, low-power MnZn ferrite material include main materials, auxiliary materials, and binders: The main material comprises, by mole fraction, 50-54.5% Fe2O3, 5.0-9.0% ZnO, 0.01-0.05% B2O3, 0.5-1% Ta2O5, and the balance Mn3O4. Based on the main material's mass fraction of 100%, the auxiliary materials include CaO 0.03~0.2%, SiO2 0.005~0.03%, Nb2O5 0.01~0.2%, Co2O3 0.1~0.6%, SnO2 0.05~0.3%, and ZrO2 0.01~0.2%.

[0019] The raw materials for preparing the medium-high frequency, low-power MnZn ferrite material of this invention include the following main materials: The main material comprises 50-54.5% Fe2O3 by mole fraction, which can be 51%, 52%, 53% or 54% in specific embodiments of the present invention; iron oxide is the raw material with the largest amount used in manganese zinc ferrite, and is used to react with Mn3O4 and ZnO during sintering to generate MnFe2O4 and ZnFe2O4 ferrite. The main material comprises 5-9% ZnO by mole fraction, which can be 6%, 7% or 8% in specific embodiments of the present invention; zinc oxide is one of the main raw materials of manganese zinc ferrite, and is used to react with Fe2O3 during sintering to generate ZnFe2O4 ferrite.

[0020] The main ingredient comprises 0.01-0.05% B2O3 by mole fraction, which may be 0.02%, 0.03% or 0.04% in specific embodiments of the present invention.

[0021] The main material comprises 0.5-1% Ta₂O₅ by mole fraction, which can be 0.6%, 0.7%, 0.8%, or 0.9% in specific embodiments of the present invention. Adding flux and Ta₂O₅, which readily penetrates grain boundaries, to the main material lowers the sintering temperature. Lowering the sintering temperature can easily lead to increased porosity. Adding flux at this point promotes grain boundary melting, which facilitates the expulsion of pores. Simultaneously, the presence of Ta₂O₅ at grain boundaries crowds out pore sites, resulting in lower porosity and smaller grains, thus reducing power consumption by 300K-1MHz.

[0022] The main material, by mole fraction, includes the balance Mn3O4; manganese tetroxide is one of the main raw materials for manganese-zinc ferrite, and is used to react with Fe2O3 during sintering to generate MnFe2O4 ferrite.

[0023] The raw materials for preparing the medium-high frequency, low-power MnZn ferrite material of the present invention include auxiliary materials. In the present invention, the mass fraction of the main material being 100% refers to its mass fraction relative to the main material. For example, if the mass fraction of the main material is 100%, the auxiliary material including 0.03~0.2% CaO means that the mass of CaO in the auxiliary material is 0.03~0.2% of the mass of the main material.

[0024] Based on the main ingredient having a mass fraction of 100%, the auxiliary material includes 0.03~0.2% CaO, which in specific embodiments of the present invention can be 0.05%, 0.08%, 0.1%, 0.12%, 0.15% or 0.18%.

[0025] Based on the main material having a mass fraction of 100%, the auxiliary material includes 0.005~0.03% SiO2, which in specific embodiments of the present invention can be 0.008%, 0.01%, 0.012%, 0.015%, 0.018%, 0.02%, 0.025% or 0.028%.

[0026] Based on the main material having a mass fraction of 100%, the auxiliary material includes 0.01-0.2% Nb2O5, which in specific embodiments of the present invention can be 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, or 0.18%.

[0027] Based on the main ingredient having a mass fraction of 100%, the auxiliary material includes 0.1-0.6% Co2O3, which can be 0.2%, 0.3%, 0.4% or 0.5% in specific embodiments of the present invention.

[0028] Based on the main material having a mass fraction of 100%, the auxiliary material includes SnO2 of 0.05-0.3%, which in specific embodiments of the present invention can be 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.25%, or 0.28%.

[0029] Based on the main material having a mass fraction of 100%, the auxiliary material includes 0.01-0.2% ZrO2, which can be 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, or 0.18% in specific embodiments of the present invention.

[0030] In this invention, the raw materials for preparing the medium-high frequency low power consumption MnZn ferrite material include a binder. The mass of the binder is preferably 0.05-0.4% of the total mass of the main material and auxiliary materials. In specific embodiments of this invention, it can be 0.1%, 0.2% or 0.3%. The binder preferably includes polyvinyl alcohol.

[0031] This invention also provides a method for preparing the medium-high frequency, low-power MnZn ferrite material described in the above technical solution, comprising the following steps: The main ingredients are mixed and then pre-fired to obtain pre-fired main ingredients; The pre-fired main material is mixed with auxiliary materials and binder and sintered to obtain the medium-high frequency low power consumption MnZn ferrite material.

[0032] This invention involves mixing the main ingredients and then pre-firing them to obtain pre-fired main ingredients.

[0033] In this invention, when mixing the main ingredients, it is preferable to first mix the main ingredients, then mix them with water, then ball mill them, and then dry and sieve them.

[0034] In this invention, the mixing time with water is preferably 0.5 to 2 hours, the drying temperature is preferably 220°C, and the drying time is preferably 1 to 3 hours.

[0035] In this invention, the pre-firing temperature is preferably 840~950℃, and in specific embodiments of this invention, it can be 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, 930℃ or 940℃; the time is preferably 0.5~3h, and in specific embodiments of this invention, it can be 1h, 1.5h, 2h or 2.5h.

[0036] After obtaining the pre-calcined main material, the present invention mixes the pre-calcined main material with auxiliary materials and binders and sinters to obtain the medium-high frequency low power consumption MnZn ferrite material.

[0037] In this invention, when the pre-fired main material is mixed with the auxiliary materials and binder, it preferably includes: The pre-fired main and auxiliary materials are mixed with water and then ball-milled. The resulting slurry is then dried and mixed with a binder. The resulting mixture is then spray-granulated and the resulting particles are then pressed into shape.

[0038] In this invention, the ball milling time is preferably 1 to 6 hours.

[0039] In this invention, the laser particle size D50 of the slurry is preferably 0.7~1μm.

[0040] In this invention, the density of the preform obtained by pressing is preferably 3.2~3.4 kg / cm³. 3 The preferred height is 8.9~9.0 mm.

[0041] In this invention, the sintering preferably includes a first sintering, a second sintering, and a third sintering performed sequentially.

[0042] The preferred sintering temperature is 700℃, and the preferred heating rate to the first sintering temperature is 1℃ / min; during the heating process to the first sintering temperature, the oxygen content is preferably 21%. The preferred sintering temperature is 1100℃, and the preferred heating rate to the second sintering temperature is 0.33℃ / min; during the heating process to the second sintering temperature, the oxygen content is preferably 0%. Densification is achieved by reducing the oxygen content, thereby reducing porosity and increasing material density.

[0043] The preferred temperature for the third sintering is 1180~1320℃, and the preferred holding time is 6~24h. The third sintering is preferably carried out in air. The preferred heating rate to the third sintering temperature is 1.33~2.5℃ / min. During the heating process to the third sintering temperature, the preferred oxygen content is 0~2.5%. In specific embodiments of the present invention, the third sintering temperature can be 1200℃, 1220℃, 1250℃, 1280℃, 1300℃, or 1320℃, the holding time can be 8h, 10h, 12h, 15h, 18h, 20h, or 22h, the heating rate to the third sintering temperature can be 1.5℃ / min, 1.8℃ / min, or 2℃ / min, and the oxygen content during the heating process to the third sintering temperature can be 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, or 2%. Low-temperature sintering in air (1180~1320℃): The increase in grain size is directly proportional to the sintering temperature. This is mainly because grain growth requires the sintering temperature to overcome the interfacial energy. Therefore, when sintering is maintained at a low temperature for a long time, the increase in grain size is not significant; only small grains gradually become uniform. Simultaneously, maintaining air sintering results in a higher oxygen content, allowing more Fe... 2+ Oxidized to Fe 3+ This makes it difficult for electrons to jump, thereby increasing resistivity and reducing eddy current losses.

[0044] After sintering, the present invention preferably further includes: cooling; The cooling preferably includes a first cooling, a second cooling, and a third cooling performed sequentially. The first cooling temperature is preferably 1000℃, and the cooling rate to the first cooling temperature is preferably 1~2℃ / min; during the cooling process to the first cooling temperature, a balanced atmosphere is preferred.

[0045] The preferred formula for calculating the equilibrium atmosphere is: logP O2 =ab / T. In the formula, b is taken as 14540, a is taken as 7.5-8.5, and T is the cooling temperature, which is taken as absolute temperature.

[0046] The preferred temperature for the second cooling is 950°C, and the preferred cooling rate to the second cooling temperature is 1~2°C / min. During the cooling process to the first cooling process, the oxygen content is preferably 0.09~0.15%. When the oxygen content is controlled at 0.09~0.15% during the cooling process, MnFe2O4 will undergo an antiferrite reaction to generate γ-Fe2O3 and γ-Mn3O4. These two substances have a similar ferrite lattice structure and have little effect on magnetism, but they can increase resistance, thereby reducing power consumption in the medium and high frequency ranges.

[0047] The temperature of the third cooling is preferably room temperature, and the cooling rate to the third cooling temperature is preferably 1~9℃ / min; during the cooling process to the third cooling temperature, the oxygen content is preferably below 70ppm. This invention also provides the application of the high-frequency low-power MnZn ferrite material in the above-described technical solution or the medium-frequency low-power MnZn ferrite material prepared by the preparation method described in the above-described technical solution in semiconductors.

[0048] The following detailed description, in conjunction with embodiments, illustrates the medium-to-high frequency, low-power MnZn ferrite materials, their preparation methods, and applications provided by this invention. However, these descriptions should not be construed as limiting the scope of protection of this invention.

[0049] Examples and Comparative Examples The preparation methods of the MnZn ferrite obtained in the examples and comparative examples are as follows: According to the main material ratios of the examples and comparative examples in Table 1, accurately weigh industrial iron oxide red (Fe2O3), industrial manganese tetroxide (Mn3O4), industrial ZnO, industrial B2O3, and industrial Ta2O5, mix them according to the ratios, and then put them into a planetary ball mill. Weigh water at a mass ratio of 40% of the main materials and put it into the planetary ball mill at the same time. Mill for 0.5 hours to mix thoroughly. Take out the mixed slurry and dry it to obtain a dry powder.

[0050] The dried powder was crushed in a crusher and filtered through a 100-mesh sieve to remove impurities. The crushed powder was then pre-fired in a muffle furnace at 940℃ for 1 hour. After cooling, the pre-fired powder was placed in a planetary ball mill with 40% water and auxiliary materials (according to the following mass percentages of the main materials: CaO 0.1%, SiO2 0.02%, Nb2O5 0.1%, Co2O3 0.5%, SnO2 0.2%, ZrO2 0.05%). The mixture was then ball-milled for 2 hours until the D50 was 0.8 μm.

[0051] After the abrasive slurry is dried, 0.1% polyvinyl alcohol (PVA) binder (by weight of the powder) is added, followed by spray granulation.

[0052] The granulated ferrite material is pressed into blanks with a height of 8.9~9.0 mm and a density of 3.2~3.4 kg / cm³. 3 The sample ring blank.

[0053] The blank sample ring is placed in a bell-shaped furnace for sintering. The sintering process is as follows: The heating rate was 1.0℃ / min from room temperature to 700℃, and the oxygen content was 21%. The temperature increased from 700℃ to 1100℃ at a rate of 0.33℃ / min, with an oxygen content of 0%. The temperature was increased from 1100℃ to 1180℃ at a rate of 1.33℃ / min, with an oxygen content of 1.5%. After reaching the holding temperature, the temperature was held for 12 hours with an oxygen content of 21%.

[0054] After the heat preservation period, cooling is carried out at a rate of 1.33℃ / min from the initial heat preservation temperature of -1000℃. The oxygen content during cooling is set according to the equilibrium atmosphere (equilibrium atmosphere formula: logP). O2 =ab / T. Where b is 14540, a is 8.2, and T is the sintering temperature (absolute temperature). The temperature range of 1000℃-950℃ requires an increase in oxygen content to improve electrical resistance. The cooling rate is 1℃ / min and the oxygen content is 0.1%.

[0055] After reaching 950℃, the cooling rate was 2.3℃ / min, and the oxygen content was controlled to below 70ppm during the cooling process.

[0056] Table 1. Main ingredients and some parameters of the examples and comparative examples

[0057] Table 2 Performance results of materials obtained from the examples and comparative examples

[0058] Because Comparative Example 1 did not include B2O3 and Ta2O5 in its main formulation, it was not suitable for low-temperature sintering, resulting in high overall power consumption. Comparative Example 2, lacking Ta2O5 in its main formulation, exhibited poor wide-temperature characteristics, with high power consumption at 100 / 120℃. Comparative Example 3, due to the addition of easily fusible B2O3 to the auxiliary materials, failed to react during pre-firing, leading to severe crystallization during the second sintering and extremely poor electrical properties.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A medium-high frequency low power loss MnZn ferrite material, characterized in that, The raw materials for preparing medium- and high-frequency low-power MnZn ferrite materials include main materials, auxiliary materials, and binders: The main material comprises, by mole fraction, 50-54.5% Fe2O3, 5.0-9.0% ZnO, 0.01-0.05% B2O3, 0.5-1% Ta2O5, and the balance Mn3O4. Based on the main material's mass fraction of 100%, the auxiliary materials include CaO 0.03~0.2%, SiO2 0.005~0.03%, Nb2O5 0.01~0.2%, Co2O3 0.1~0.6%, SnO2 0.05~0.3% and ZrO2 0.01~0.2%.

2. The medium-high frequency low power loss MnZn ferrite material according to claim 1, characterized in that, The adhesive includes polyvinyl alcohol.

3. The medium-high frequency, low-power MnZn ferrite material according to claim 2, characterized in that, The adhesive accounts for 0.05 to 0.4% of the total mass of the main material and auxiliary materials.

4. The method for preparing the medium-high frequency, low-power MnZn ferrite material according to any one of claims 1 to 3, characterized in that, Includes the following steps: The main ingredients are mixed and then pre-fired to obtain pre-fired main ingredients; The pre-fired main material is mixed with auxiliary materials and binder and sintered to obtain the medium-high frequency low power consumption MnZn ferrite material.

5. The preparation method according to claim 4, characterized in that, When mixing the main ingredients, the process includes: initially mixing the main ingredients and then mixing them with water, followed by drying.

6. The preparation method according to claim 4, characterized in that, The pre-firing temperature is 840~950℃, and the time is 0.5~3h.

7. The preparation method according to claim 4, characterized in that, When mixing the pre-fired main material with auxiliary materials and binders, the process includes: The pre-fired main and auxiliary materials are mixed with water and then ball-milled. The resulting slurry is then dried and mixed with a binder. The resulting mixture is then spray-granulated and the resulting particles are then pressed into shape.

8. The preparation method according to claim 4, characterized in that, The sintering includes a first sintering, a second sintering, and a third sintering performed sequentially. The first sintering temperature is 700℃, and the heating rate to the first sintering temperature is 1℃ / min; during the heating process to the first sintering temperature, the oxygen content is 21%. The second sintering temperature is 1100℃, and the heating rate to the second sintering temperature is 0.33℃ / min; during the heating process to the second sintering temperature, the oxygen content is 0%. The third sintering temperature is 1180~1320℃, the holding time is 6~24h, and the third sintering is carried out in air; the heating rate to the third sintering temperature is 1.33~2.5℃ / min; during the heating to the third sintering temperature, the oxygen content is 0~2.5%.

9. The preparation method according to claim 7 or 8, characterized in that, After sintering, the process further includes: cooling; The cooling includes a first cooling, a second cooling, and a third cooling performed sequentially. The first cooling temperature is 1000℃, and the cooling rate to the first cooling temperature is 1~2℃ / min; during the cooling process to the first cooling temperature, an equilibrium atmosphere is maintained. The second cooling temperature is 950℃, and the cooling rate to the second cooling temperature is 1~2℃ / min; during the cooling process to the first cooling temperature, the oxygen content is 0.09~0.15%; The third cooling temperature is room temperature, and the cooling rate to the third cooling temperature is 1~9℃ / min; during the cooling process to the first cooling temperature, the oxygen content is below 70ppm.

10. The application of the medium-frequency low-power MnZn ferrite material according to any one of claims 1 to 3 or the medium-frequency low-power MnZn ferrite material prepared by the preparation method according to any one of claims 4 to 9 in semiconductors.

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