Manganese-magnesium ferrite material with wide temperature range and low loss under MHz frequency and preparation method of manganese-magnesium ferrite material

Abstract

The invention discloses a wide-temperature low-loss manganese-magnesium ferrite material under MHz frequency and a preparation method thereof. The manganese-magnesium ferrite material comprises a main component and an auxiliary component. The main component is composed of ferric oxide, magnesium oxide, manganese oxide and cobalt oxide. The auxiliary components comprise calcium carbonate, silicon dioxide and tantalum pentoxide. The preparation method of the manganese-zinc ferrite material comprises the following steps: preparing materials, and carrying out primary ball milling; pre-sintering is performed; performing secondary ball milling; performing granulation; forming is conducted; and sintering. The manganese-magnesium ferrite prepared by the invention has relatively low power loss under a high-frequency condition, the power loss is relatively small along with temperature change in an ultra-wide temperature range of 0-140 DEG C, and the manganese-magnesium ferrite has good high-frequency wide-temperature low-loss performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of soft magnetic power ferrites, and relates to a MnMg ferrite material with wide temperature and low loss at MHz frequencies and a preparation method thereof. Background Art

[0002] With the development of 5G communication technology and the wide commercial use of the third-generation wide bandgap semiconductors, power electronic devices are accelerating their development towards high frequency, miniaturization, and high energy efficiency, which provides impetus for the development of soft magnetic ferrites. Soft magnetic MnZn ferrites have significant advantages such as high resistivity, low power loss, and low cost, and are widely used in various power electronic devices. However, the development of high-frequency soft magnetic ferrites lags behind the requirements of high-frequency power devices. The application of wide bandgap semiconductors enables power devices to potentially operate in the MHz frequency band, which requires ferrites to have very good performance at frequencies within the MHz range. However, when the operating frequency reaches MHz, the P cv of MnZn ferrites usually increases sharply, which reduces the energy efficiency of power devices and thus hinders the application of MnZn ferrites under such high-frequency conditions.

[0003] At MHz frequencies, the main reasons for the deterioration of the performance of soft magnetic ferrites are the sharp increase in eddy current loss and residual loss. Eddy current loss becomes very important at higher frequencies above 100 kHz and depends on the resistivity of polycrystalline ferrites. It can be effectively reduced by adding appropriate dopants to form high-resistance grain boundaries at the grain boundaries. Residual loss is presumably the loss caused by domain wall resonance and spin resonance. Domain wall resonance only becomes significant at MHz frequencies in multi-domain grains. An effective way to reduce residual loss is to control the grain size to make it in a single-domain state to avoid harmonic resonance phenomena.

[0004] Patent CN118405914A proposes a preparation method for reducing the loss of high-frequency ferrite cores, using a tempering process and cooling in a nitrogen atmosphere to reduce the loss of high-frequency ferrite cores. The power loss at 2 MHz, 50 mT, and 100 °C is below 500 kW·m -3 .

[0005] Patent CN118439863A proposes a low-loss soft magnetic ferrite material and a preparation method thereof, using a hydrothermal method to prepare a layered ferrite precursor and introducing lithium oxide into the pre-burned mixture to reduce the loss of the ferrite core. The power loss at 1 MHz, 50 mT, and 100 °C is about 100 kW·m -3 .

[0006] Patent CN118184329A proposes a high B sLow-loss MHz Mn-Zn power ferrite and preparation method thereof, by doping CaSiO3 to optimize the formula and reduce the eddy current loss, the loss is 50 kW·m at 1 MHz, 50 mT, and 25 °C -3 , and the power loss at 3 MHz, 30 mT, and 25 °C is about 200 kW·m -3 .

[0007] The currently published high-frequency low-loss power ferrites have relatively low losses near 1 MHz - 3 MHz, while at 5 MHz and higher frequencies, the losses of Mn-Zn ferrites are still relatively high. In summary, it is crucial to develop a Mn-Mg ferrite material with wide-temperature low loss at 5 MHz and higher frequencies. Summary of the Invention

[0008] The purpose of the present invention is to solve the above-mentioned problems and provide a Mn-Mg ferrite material with wide-temperature low loss at MHz frequencies and its preparation method.

[0009] In the first aspect, the present invention provides a Mn-Mg ferrite material with wide-temperature low loss at MHz frequencies, including a main component and an auxiliary component;

[0010] The main component is composed of the following components in terms of mole percentage: Fe2O3 53.20 - 55.20 mol%, MgO 0.1 - 0.4 mol%, Co3O4 0.33 - 0.43 mol%, and the balance is MnO;

[0011] The auxiliary component, in terms of the mass percentage of the main component, includes: CaCO3 1300 ppm - 1800 ppm, SiO2 100 ppm - 300 ppm, and Ta2O5 150 ppm - 750 ppm.

[0012] Preferably, the main component is composed of the following components in terms of mole percentage: Fe2O3 55.10 mol%, MgO 0.1 mol%, Co3O4 0.33 mol%, and the balance is MnO;

[0013] The auxiliary component, in terms of the mass percentage of the main component, includes: CaCO3 1500 ppm, SiO2 150 ppm, and Ta2O5 450 ppm.

[0014] In the second aspect, the present invention provides a preparation method of a Mn-Mg ferrite material with wide-temperature low loss at MHz frequencies, and the method includes:

[0015] Weigh the powder materials Fe2O3, MnO, MgO, and Co3O4 according to the main component ratio and mix them evenly initially;

[0016] Pour the weighed main component powder materials into a ball mill tank, add deionized water and perform primary ball milling;

[0017] The slurry obtained after the first ball milling is dried, and the dried powder is put into a muffle furnace for pre-sintering treatment;

[0018] The pre-sintered powder and the additive are put into a ball milling tank, deionized water is added, and secondary ball milling is carried out to make them fully mixed;

[0019] The powder obtained by drying the slurry after the second ball milling is added with polyvinyl alcohol (PVA) for manual granulation;

[0020] The granulated powder particles are put into a mold cavity and pressed into a magnetic ring under an external pressure;

[0021] The formed magnetic ring is put into a tube-type controllable resistance furnace for atmosphere sintering.

[0022] Preferably, the rotation speed of the first ball milling is 120 r / min, and the ball milling time is 16 h - 24 h.

[0023] Preferably, the pre-sintering temperature of the muffle furnace is 800 - 850 °C, the heat preservation time is 3 - 5 h, and it is cooled to room temperature with the furnace.

[0024] Preferably, the rotation speed of the second ball milling is 120 r / min, and the ball milling time is 16 h - 24 h.

[0025] Preferably, the mass ratio of the polyvinyl alcohol (PVA) to the powder dried after the second ball milling is 100:8 - 12.

[0026] Preferably, the sintering temperature in the tube-type controllable resistance furnace is 1150 °C - 1170 °C, more preferably 1170 °C, and the sintering temperature is kept for 5 h - 7 h.

[0027] Preferably, it is taken out after naturally cooling to below 100 °C in the tube-type controllable resistance furnace after sintering, and the equilibrium oxygen partial pressure is adopted during the cooling process.

[0028] Compared with the existing technology, the manganese-magnesium ferrite preparation technology proposed by the present invention has at least the following beneficial effects:

[0029] On the basis of the main components of ferric oxide, manganese oxide, and cobalt oxide, by introducing 0.1 - 0.4 mol% of MgO, the present invention can significantly improve the grain boundary resistivity. MgO effectively inhibits the high-frequency eddy current loss by forming high-resistance grain boundaries. Moreover, Co 2+ ions in cobalt oxide have positive magnetocrystalline anisotropy, and the negative K1 value of the compensated spinel ferrite is made up through the synergistic effect of cobalt oxide and MgO, thereby broadening the temperature application range.

[0030] By defining the MgO content (0.1 - 0.4 mol%) and completely excluding ZnO, and combining with the magnetocrystalline compensation effect of Co3O4, the present invention successfully solves the core problems of high loss and poor temperature stability of high-frequency ferrite materials in the high-frequency band (5 - 9 MHz). Description of the Drawings

[0031] Figure 1 It is a typical curve graph showing the variation of power loss with temperature of Example 1 of the present invention and Comparative Example 1*, Comparative Example 2*, Comparative Example 3*, and Comparative Example 4* at 5000 kHz and 10 mT.

[0032] Figure 2 It is a typical curve graph showing the variation of power loss with temperature of Example 1 of the present invention and Comparative Example 1*, Comparative Example 2*, Comparative Example 3*, and Comparative Example 4* at 7000 kHz and 5 mT.

[0033] Figure 3 It is a typical curve graph showing the variation of power loss with temperature of Example 1 of the present invention and Comparative Example 1*, Comparative Example 2*, Comparative Example 3*, and Comparative Example 4* at 7000 kHz and 10 mT. Detailed Embodiments

[0034] The following will describe the implementation schemes of the present invention in detail in combination with the implementation modes and examples. However, those skilled in the art will understand that the following implementation modes and examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the examples in the present invention, all other examples obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. Those not specifying specific conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not indicating the manufacturer can be conventional products obtained through commercial purchase.

[0035] It should be noted that:

[0036] In the present invention, if there is no special indication, all the implementation modes and preferred implementation methods mentioned in this article can be combined with each other to form a new technical solution.

[0037] In the present invention, if there is no special indication, all the technical features and preferred features mentioned in this article can be combined with each other to form a new technical solution.

[0038] In the present invention, if there is no special indication, the percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0039] In the present invention, if there is no special indication, the various components or their preferred components involved can be combined with each other to form a new technical solution.

[0040] In the present invention, unless otherwise specified, the "range" disclosed in the present invention can be in the form of one or more lower limits and one or more upper limits respectively.

[0041] In the present invention, unless otherwise stated, each reaction or operation step can be carried out sequentially or in order. Preferably, the reaction methods herein are carried out sequentially.

[0042] Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to persons skilled in the art. In addition, any method or material similar or equivalent to the described content can also be applied to the present invention.

[0043] The inventors found that doping non-magnetized Zn 2+ ions would reduce the magnetocrystalline anisotropy constant K1 of the ferrite and increase the initial permeability μ i , according to Snoek's law, the resonance frequency f r is negatively correlated with μ i , doping Zn 2+ makes the residual loss P rv and the eddy current loss P cv increase sharply at high frequencies.

[0044] Based on this, on the one hand, at least one embodiment discloses a high-frequency wide-temperature low-loss manganese-magnesium ferrite material comprising a main component and an auxiliary component;

[0045] The main component, by weight of the main component, consists of Fe2O3: 53.20 - 55.20 mol%, MgO: 0.1 - 1.5 mol%, Co3O4: 0.33 - 0.43 mol%, and the balance is MnO; preferably, it consists of Fe2O3: 55.10 mol%, MgO: 0.10 mol%, Co3O4: 0.33 mol%, and the balance is MnO;

[0046] The auxiliary component, by weight of the main component, includes CaCO3: 1300 ppm - 1800 ppm, SiO2: 100 ppm - 300 ppm, Ta2O5: 150 ppm - 750 ppm. Preferably, CaCO3: 1500 ppm, SiO2: 150 ppm, Ta2O5: 450 ppm.

[0047] On the other hand, at least one embodiment discloses a method for preparing a high-frequency wide-temperature low-loss manganese-magnesium ferrite, comprising the following steps:

[0048] 1) Ingredients. Using Fe2O3, MnO, MgO, and Co3O4 as raw materials, weigh the raw materials according to the ratio of 53.20 - 55.20 mol% of Fe2O3, 0.1 - 0.4 mol% of MgO, 0.33 - 0.43 mol% of Co3O4, and the balance of MnO.

[0049] 2) Primary ball milling. Put the weighed powder into the ball milling tank, add 400 - 450 mL of deionized water and ball mill for 16 - 24 h.

[0050] 3) Pre - sintering. Dry the ball - milled slurry in the oven, and put the obtained powder into a muffle furnace for pre - sintering treatment. The pre - sintering temperature is 800 - 850 °C, and keep the temperature for 3 - 5 h.

[0051] 4) Secondary ball milling. Put the pre - sintered powder and additives into the ball milling tank together, and add 400 - 450 mL of deionized water for ball milling.

[0052] 5) Granulation. Dry the slurry after secondary ball milling in the oven, and add 8 wt% - 12 wt% polyvinyl alcohol solution (PVA) to the obtained powder for granulation.

[0053] 6) Molding. Put the granulated powder particles into the mold cavity and press them into magnetic rings under external pressure.

[0054] 7) Sintering. Put the pressed magnetic rings into a tube - type controllable resistance furnace for atmosphere sintering. The sintering temperature is 1150 °C - 1170 °C; keep the temperature for 5 h - 7 h at the sintering temperature, take them out when the furnace temperature is lower than 100 °C, and adopt balanced oxygen partial pressure during the cooling process to obtain ferrites.

[0055] Typically but not limited to, in steps 2) and 4), the wet ball milling time is 16 h, the amount of deionized water used is 450 mL, and the rotation speed of the ball mill is 120 r / min. In step 3), the pre - sintering temperature is 850 °C, and the heating rate is 2 °C / min. In step 5), the concentration of the polyvinyl alcohol aqueous solution is 10 wt%, and the mass ratio of the polyvinyl alcohol aqueous solution to the granular material is 10:1. In step 6), the pressure of hydraulic molding is 34 KN, and the pressed magnetic ring is (Ф13 mm * Ф8 mm * 7 mm).

[0056] Through controlling the main components and auxiliary components and continuously improving the sintering temperature, etc., the present invention prepares high - frequency wide - temperature low - loss manganese - magnesium ferrites. At 1 MHz and 50 mT, the power losses at 25 °C and 100 °C are respectively not higher than 50 kW·m -3 and 85 kW·m -3 ; at 3 MHz and 30 mT, the loss at 25 °C is not higher than 220 kW·m -3 , and the loss at 100 °C is not higher than 325 kW·m -3The power losses at 25 °C and 100 °C are not higher than 240 kW·m under the conditions of 5 MHz and 10 mT. -3 The power losses at 25 °C and 100 °C are not higher than 130 kW·m and 120 kW·m respectively under the conditions of 7 MHz and 5 mT. -3 and 120 kW·m -3 The power losses at 25 °C and 100 °C are not higher than 520 kW·m and 470 kW·m respectively under the conditions of 7 MHz and 10 mT. -3 and 470 kW·m -3 The power losses at 25 °C and 100 °C are not higher than 215 kW·m and 275 kW·m respectively under the conditions of 9 MHz and 5 mT. -3 and 275 kW·m -3 The requirements for manganese-magnesium ferrite materials with wide temperature range and low loss at high frequencies of 1 MHz - 7 MHz are met.

[0057] It should be understood that the content not described in detail in the above description of the preparation method or the obtained product are common parameters that are easily conceivable by those skilled in the art and can be adjusted by those skilled in the art according to the actual situation, such as the sintering temperature, etc. Therefore, the detailed description thereof can be omitted. For the understanding of those skilled in the art, the technical solutions of the present invention will be further described in detail below with reference to specific examples and comparative examples.

[0058] Example 1

[0059] A manganese-magnesium ferrite material includes a main component and an auxiliary component. The main component consists of Fe2O3: 55.10 mol%, MgO: 0.10 mol%, Co3O4: 0.33 mol%, and the balance is MnO; the auxiliary component, based on the weight of the main component, includes CaCO3: 1500 ppm, SiO2: 150 ppm, Ta2O5: 450 ppm.

[0060] The preparation method of the above manganese-magnesium ferrite includes the following steps:

[0061] 1) Batching: According to the main formula ratio, weigh the powders Fe2O3, MnO, MgO, and Co3O4 and mix them evenly preliminarily.

[0062] 2) Primary ball milling: Put the weighed powders into a ball milling tank, add 450 mL of deionized water and ball mill at a rotation speed of 120 r / min for 16 h.

[0063] 3) Pre-sintering: Dry the ball-milled slurry in an oven, and place the obtained powder in a muffle furnace for pre-sintering treatment. The pre-sintering temperature is 850 °C and the holding time is 3 h.

[0064] 4) Secondary ball milling. The pre-fired powder and additives are put into a ball milling tank together, 450 mL of deionized water is added, and ball milling is carried out at a rotation speed of 120 r / min for 16 h.

[0065] 5) Granulation: The slurry after secondary ball milling is dried in an oven, and the obtained powder is granulated by adding 10 wt% polyvinyl alcohol solution (PVA).

[0066] 6) Molding: The granulated powder particles are put into a mold cavity and pressed into a magnetic ring (Ф13mm*Ф8mm*7mm) by applying external pressure.

[0067] 7) Sintering: The pressed magnetic ring is put into a tube-type controllable resistance furnace for atmosphere sintering, and the sintering temperature is 1170 °C; it is kept at the sintering temperature for 6 h, taken out when the furnace temperature is lower than 100 °C, and the cooling process adopts balanced oxygen partial pressure to obtain ferrite.

[0068] Example 2

[0069] A manganese-magnesium ferrite material includes a main component and an auxiliary component. The main component consists of Fe2O3: 55.10 mol%, MgO: 0.20 mol%, Co3O4: 0.33 mol%, and the balance is MnO; the auxiliary component, based on the weight of the main component, includes CaCO3: 1500 ppm, SiO2: 150 ppm, Ta2O5: 450 ppm.

[0070] The preparation method of the above-mentioned manganese-magnesium ferrite includes the following steps:

[0071] 1) Batching: According to the main formula ratio, weigh the powders Fe2O3, MnO, MgO, and Co3O4 and mix them evenly preliminarily.

[0072] 2) Primary ball milling: Put the weighed powders into a ball milling tank, add 450 mL of deionized water and ball mill at a rotation speed of 120 r / min for 16 h.

[0073] 3) Pre-firing: The slurry after ball milling is dried in an oven, and the obtained powder is put into a muffle furnace for pre-firing treatment. The pre-firing temperature is 850 °C and it is kept for 3 h.

[0074] 4) Secondary ball milling. The pre-fired powder and additives are put into a ball milling tank together, 450 mL of deionized water is added, and ball milling is carried out at a rotation speed of 120 r / min for 16 h.

[0075] 5) Granulation: The slurry after secondary ball milling is dried in an oven, and the obtained powder is granulated by adding 10 wt% polyvinyl alcohol solution (PVA).

[0076] 6) Forming: The powdered particles after granulation are placed into the mold cavity and pressed into magnetic rings (Ф13mm*Ф8mm*7mm) by applying external pressure.

[0077] 7) Sintering: The pressed magnetic rings are placed into a tube-type controllable resistance furnace for atmosphere sintering. The sintering temperature is 1170°C; keep it at the sintering temperature for 6 hours, and take it out when the furnace temperature is lower than 100°C. The cooling process adopts balanced oxygen partial pressure to obtain ferrite.

[0078] Example 3

[0079] A manganese-magnesium ferrite material, including a main component and an auxiliary component. The main component consists of Fe2O3: 55.10 mol%, MgO: 0.30 mol%, Co3O4: 0.33 mol%, and the balance is MnO; calculated based on the weight of the main component, the auxiliary component includes CaCO3: 1500 ppm, SiO2: 150 ppm, Ta2O5: 450 ppm.

[0080] The preparation method of the above-mentioned manganese-magnesium ferrite includes the following steps:

[0081] 1) Batching: Weigh the powdered materials Fe2O3, MnO, MgO, and Co3O4 according to the main formula ratio and mix them evenly preliminarily.

[0082] 2) Primary ball milling: Put the weighed powdered materials into the ball milling tank, add 450 mL of deionized water, and ball mill at a rotation speed of 120 r / min for 16 hours.

[0083] 3) Pre-sintering: Dry the ball-milled slurry in an oven, and place the obtained powdered materials in a muffle furnace for pre-sintering treatment. The pre-sintering temperature is 850°C, and keep it for 3 hours.

[0084] 4) Secondary ball milling. Put the pre-sintered powdered materials and additives into the ball milling tank together, add 450 mL of deionized water, and ball mill at a rotation speed of 120 r / min. The ball milling time is 16 hours.

[0085] 5) Granulation: Dry the slurry after secondary ball milling in an oven, and add 10% polyvinyl alcohol solution (PVA) to the obtained powder for granulation.

[0086] 6) Forming: The powdered particles after granulation are placed into the mold cavity and pressed into magnetic rings (Ф13mm*Ф8mm*7mm) by applying external pressure.

[0087] 7) Sintering: The pressed magnetic rings are placed into a tube-type controllable resistance furnace for atmosphere sintering. The sintering temperature is 1170°C; keep it at the sintering temperature for 6 hours, and take it out when the furnace temperature is lower than 100°C. The cooling process adopts balanced oxygen partial pressure to obtain ferrite.

[0088] Example 4

[0089] A manganese-magnesium ferrite material, comprising a main component and an auxiliary component. The main component consists of Fe2O3: 55.10 mol%, MgO: 0.40 mol%, Co3O4: 0.33 mol%, and the balance is MnO; the auxiliary component, based on the weight of the main component, includes CaCO3: 1500 ppm, SiO2: 150 ppm, Ta2O5: 450 ppm.

[0090] The preparation method of the above-mentioned manganese-magnesium ferrite includes the following steps:

[0091] 1) Weighing materials: According to the main formula ratio, weigh the powder materials Fe2O3, MnO, MgO, and Co3O4, and preliminarily mix them evenly.

[0092] 2) Primary ball milling: Put the weighed powder materials into a ball milling tank, add 450 mL of deionized water, and ball mill for 16 h at a rotation speed of 120 r / min.

[0093] 3) Pre-sintering: Dry the ball-milled slurry in an oven, and put the obtained powder materials into a muffle furnace for pre-sintering treatment. The pre-sintering temperature is 850 °C, and keep warm for 3 h.

[0094] 4) Secondary ball milling. Put the pre-sintered powder materials and additives into a ball milling tank together, add 450 mL of deionized water, and ball mill at a rotation speed of 120 r / min. The ball milling time is 16 h.

[0095] 5) Granulation: Dry the slurry after secondary ball milling in an oven, and add 10% polyvinyl alcohol solution (PVA) to the obtained powder for granulation.

[0096] 6) Molding: Put the granulated powder particles into a mold cavity, and apply external pressure to press them into a magnetic ring (Ф13 mm * Ф8 mm * 7 mm).

[0097] 7) Sintering: Put the pressed magnetic ring into a tube-type controllable resistance furnace for atmosphere sintering. The sintering temperature is 1170 °C; keep warm at the sintering temperature for 6 h, take it out when the furnace temperature is lower than 100 °C, and adopt balanced oxygen partial pressure during the cooling process to obtain ferrite.

[0098] Comparative Example 1

[0099] Its preparation process is the same as that of Example 1. The main component of the ferrite consists of Fe2O3: 55.10 mol%, MgO: 0 mol%, Co3O4: 0.33 mol%, and the balance is MnO; the auxiliary component, based on the weight of the main component, includes CaCO3: 1500 ppm, SiO2: 150 ppm, Ta2O5: 450 ppm;.

[0100] The above-mentioned ferrite preparation method includes the following steps:

[0101] 1) Ingredients: According to the main formula ratio, weigh the powder materials Fe2O3, MnO, and Co3O4, and mix them evenly preliminarily.

[0102] 2) Primary ball milling: Put the weighed powder materials into the ball milling tank, add 450 mL of deionized water, and ball mill for 16 h at a rotation speed of 120 r / min.

[0103] 3) Pre-sintering: Dry the ball milled slurry in the oven, and put the obtained powder materials into the muffle furnace for pre-sintering treatment. The pre-sintering temperature is 850 °C, and keep the temperature for 3 h.

[0104] 4) Secondary ball milling. Put the pre-sintered powder materials and additives into the ball milling tank together, add 450 mL of deionized water, and ball mill at a rotation speed of 120 r / min. The ball milling time is 16 h.

[0105] 5) Granulation: Dry the secondary ball milled slurry in the oven, and add 10% polyvinyl alcohol solution (PVA) to the obtained powder for granulation.

[0106] 6) Molding: Put the granulated powder particles into the mold cavity, and apply external pressure to press them into a magnetic ring (Ф13 mm * Ф8 mm * 7 mm).

[0107] Sintering: Put the pressed magnetic ring into the tube type controllable resistance furnace for atmosphere sintering. The sintering temperature is 1170 °C; keep the temperature at the sintering temperature for 6 h, take it out when the furnace temperature is lower than 100 °C, and adopt balanced oxygen partial pressure during the cooling process to obtain ferrite.

[0108] Comparative Example 2 - 4

[0109] The preparation process conditions are the same as those of Comparative Example 1, but the MgO content is adjusted to 0.5 mol%, 1.0 mol%, and 1.5 mol% respectively.

[0110] Table 1 Main components and auxiliary component formulations of ferrite prepared in Examples 1 - 4 and Comparative Examples 1 - 4

[0111]

[0112]

[0113] Table 1

[0114] Note: The schemes with * in Table 1 are comparative examples. 1 - 4 are the examples of the present invention, and 1* - 4* are comparative examples.

[0115] Test the power consumption P of the ferrite at 25 °C and 100 °C under the conditions of 1 MHz / 50 mT, 3 MHz / 30 mT, 5 MHz / 10 mT, 7 MHz / 5 mT, 7 MHz / 10 mT, and 9 MHz / 5 mT by the Yantong SY - 8218 type AC B - H analyzercv (KW / m 3 ), and the test results are shown in Table 2.

[0116] Table 2 Test Performance of Ferrite Prepared in Examples 1-4 and Comparative Examples 1-4

[0117]

[0118] It can be seen from the data in Table 2 that:

[0119] 1) The main components of Examples 1 to 4 are all within the scope defined by the present invention. By adjusting the MgO content, at 1 MHz / 50 m condition and 25 °C, the loss is not higher than 50 kW·m -3 , and at 100 °C, the loss is not higher than 85 kW·m -3 ; at 3 MHz / 30 m condition, at 25 °C, the loss is not higher than 220 kW·m -3 , and at 100 °C, the loss is not higher than 325 kW·m -3 ; at 5 MHz / 10 m condition, at 25 °C, the loss is not higher than 240 kW·m -3 , and at 100 °C, the loss is not higher than 240 kW·m -3 ; at 7 MHz / 5 m condition, at 25 °C, the loss is not higher than 130 kW·m -3 , and at 100 °C, the loss is not higher than 120 kW·m -3 ; at 7 MHz / 10 m condition, at 25 °C, the loss is not higher than 520 kW·m -3 , and at 100 °C, the loss is not higher than 470 kW·m -3 ; with the increase of frequency for the samples of Examples 1 to 4, they also maintain a low loss at high frequencies and high temperatures of 5 MHz - 7 MHz, achieving the goal of low loss at wide temperature and high frequency, and meeting the requirements of ferrite materials in high-frequency application fields.

[0120] 2) The MgO content of Comparative Examples 1 to 4 is outside the scope defined by the present invention. Comparative Example 1 does not add MgO, and at 7 MHz / 10 mT condition and 100 °C, the loss is as high as 1158 kW·m -3 , and the loss of the comparative example samples is relatively high at 1 MHz / 50 mT and 3 MHz / 30 mT conditions. With the increase of frequency, the loss of the samples increases significantly at high temperatures.

[0121] Figure 1 、 Figure 2 、 Figure 3The temperature characteristic curves of the core losses of Example 1 and Comparative Examples 1-4 under the conditions of 5 MHz / 10 mT, 7 MHz / 5 mT, and 7 MHz / 10 mT. It can be seen from the figure that the loss change of Example 1 is small in the wide temperature range of 0-140 °C, and the temperature-power consumption curve shows a horizontal trend, having good wide-temperature and low-loss performance. The losses of Comparative Examples 1-4 change greatly with temperature. Under the condition of 7 MHz / 10 mT, the loss increases sharply with the increase of temperature, which does not quite meet the performance indicators of high-frequency, wide-temperature and low-power manganese-magnesium ferrite materials.

[0122] The above embodiments are not limitations on the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solution of the present invention also fall within the protection scope of the present invention.

Claims

1. A wide-temperature and low-loss manganese-magnesium ferrite material at MHz frequency, comprising a main component and an auxiliary component, characterized in that: The main components, in terms of mole percentage, are composed of the following components: 53.20 - 55.20 mol% of Fe2O3, 0.1 - 0.4 mol% of MgO, 0.33 - 0.43 mol% of Co3O4, and the balance of MnO; The auxiliary components, in terms of the mass percentage of the main components, include: 1300 ppm - 1800 ppm of CaCO3, 100 ppm - 300 ppm of SiO2, and 150 ppm - 750 ppm of Ta2O5.

2. The wide-temperature and low-loss manganese-magnesium ferrite material at MHz frequency according to claim 1, characterized in that: The main components, in terms of mole percentage, are composed of the following components: 55.10 mol% of Fe2O3, 0.1 mol% of MgO, 0.33 mol% of Co3O4, and the balance of MnO; The auxiliary components, in terms of the mass percentage of the main components, include: 1500 ppm of CaCO3, 150 ppm of SiO2, and 450 ppm of Ta2O5.

3. A method for preparing a wide-temperature and low-loss manganese-magnesium ferrite material at MHz frequencies as described in any one of claims 1-2, characterized in that: The method includes: Weigh the powder materials Fe2O3, MnO, MgO, and Co3O4 according to the main component ratio and mix them evenly initially; Pour the weighed main component powder materials into a ball mill tank, add deionized water and conduct primary ball milling; Dry the slurry obtained after primary ball milling, and place the dried powder materials into a muffle furnace for pre-sintering treatment; Put the pre-sintered powder materials and additives into a ball mill tank, add deionized water, and conduct secondary ball milling to make them fully mixed; Add polyvinyl alcohol (PVA) to the powder materials obtained by drying the slurry after secondary ball milling and manually granulate them; Put the granulated powder particles into a mold cavity and press them into a magnetic ring under an external pressure; Place the formed magnetic ring into a tube-type controllable resistance furnace for atmosphere sintering.

4. The method according to claim 3, wherein The rotation speed of the primary ball milling is 120 r / min, and the ball milling time is 16 h - 24 h.

5. The method according to claim 3, wherein The pre-sintering temperature of the muffle furnace is 800 - 850 °C, the heat preservation time is 3 - 5 h, and it is cooled to room temperature with the furnace.

6. The method according to claim 3, wherein The rotation speed of the secondary ball milling is 120 r / min, and the ball milling time is 16 h - 24 h.

7. The method according to claim 3, wherein The mass ratio of the polyvinyl alcohol (PVA) to the powder materials dried after secondary ball milling is 100:8 - 12.

8. The method according to claim 3, characterized in that The sintering temperature in the tube-type controllable resistance furnace is 1150 °C - 1170 °C, and it is heat-preserved at the sintering temperature for 5 h - 7 h.

9. The method according to claim 8, wherein The sintering temperature in the tube-type controllable resistance furnace is 1170 °C.

10. The method according to claim 3, characterized in that After sintering in the tube-type controllable resistance furnace, it is naturally cooled and taken out when the temperature is lower than 100 °C, and the equilibrium oxygen partial pressure is adopted during the cooling process.

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