Ferrite material, method for manufacturing same, magnetic component, and device

Abstract

The present application provides a ferrite material, a manufacturing method thereof, a magnetic component and a device, relating to the technical field of soft ferrite. The ferrite material has a core-shell structure and at least includes a core layer and a shell layer; the content of Fe<supgt;2+< / supgt; in the core layer is different from the content of Fe<supgt;2+< / supgt> in the shell layer; the different contents of Fe<supgt;2+< / supgt> are obtained through the regulation of the sintering process. The present application can enable the magnetic properties of the ferrite material and the magnetic component to change less in a wide temperature range, improve the power consumption stability of the ferrite material and the magnetic component in a wide temperature range, and meet the usage requirements of various existing magnetic components.

Description

Technical Field

[0001] This application relates to the technical field of soft magnetic ferrites, and particularly to a ferrite material, a manufacturing method thereof, a magnetic component and a device. Background Art

[0002] As an important component material, soft magnetic ferrite materials can be used to make magnetic cores for the manufacture of various inductors, transformers, filters and chokes, and are widely used in modern power, electronic information and other fields. With the continuous progress of industry and science and technology, higher requirements are put forward for electronic components. While ensuring excellent magnetic properties, electronic components are becoming more and more high-frequency, miniaturized, and low-loss, requiring lower operating losses and a higher operating temperature range. Based on this, power ferrite materials have become a research hotspot of soft magnetic ferrite materials in recent years.

[0003] In recent years, as an important soft magnetic material, power ferrite materials have been widely used in various electronic devices such as electronic transformers, chokes, and filters, and can be widely used in industrial automation, automobiles, computers and external devices, digital communication and analog communication devices, the Internet, household appliances, aerospace and military and other fields. Exemplarily, many components in automobiles use power ferrite materials, and with the advent of the trend of automotive intelligence, the above-mentioned electronic components are increasingly applied to automobiles. Due to the characteristics of the use environment of automobiles, it is required that these electronic components can work normally in a relatively wide temperature range (the high temperature can reach 140 °C, and the low temperature can reach -40 °C). Generally speaking, the loss characteristics, saturation magnetic induction intensity Bs, magnetic permeability, etc. of ferrite materials will change greatly with the change of the use temperature, and these changes in magnetic properties will cause the normal operating point of electronic components to drift, resulting in unstable or even failure of the relevant systems. Therefore, in order to ensure the stable application of ferrite materials in intelligent vehicles, it is necessary to provide a ferrite material with less change in magnetic properties in a relatively wide temperature range.

[0004] In the prior art, in order to make the ferrite have a lower power consumption within the working temperature range, generally, the formula or composition of the material is changed, such as by doping certain elements. For example, the ferrite improves the temperature stability of magnetic properties by doping Co (cobalt) elements. However, at present, the power loss of the best mass-produced material at 140 °C is more than 30% higher than the loss at its valley point temperature. Obviously, the power consumption stability within its working temperature range still needs to be improved.

[0005] In view of this, the present application is specifically proposed. Summary of the Invention

[0006] The purpose of the present application is to provide a ferrite material, a manufacturing method thereof, a magnetic component, and a device, which can make the magnetic properties of the ferrite material and the magnetic component change less in a wide temperature range, improve the power consumption stability of the ferrite material and the magnetic component in a wide temperature range, and can overcome the above problems or at least partially solve the above technical problems.

[0007] To achieve the above object, the technical solution adopted in the present application is as follows:

[0008] According to one aspect of the present application, the present application provides a ferrite material, the ferrite material has a core-shell structure and at least includes a core layer and a shell layer;

[0009] The Fe 2+ content in the core layer is different from the Fe 2+ content in the shell layer; the different Fe 2+ contents are obtained through the regulation of the sintering process.

[0010] In a possible implementation manner, the ferrite material further includes an intermediate layer, the intermediate layer is located between the core layer and the shell layer, and the intermediate layer is one or more layers;

[0011] The Fe 2+ content in the core layer, the Fe 2+ content in the intermediate layer, and the Fe 2+ content in the shell layer are all different.

[0012] In a possible implementation manner, the Fe 2+ content shows a gradient distribution in the core layer, the intermediate layer, and the shell layer.

[0013] According to another aspect of the present application, the present application provides a magnetic component, and the manufacturing material of the magnetic component includes the ferrite material as described above.

[0014] Optionally, the magnetic component includes an inductor, a transformer, a filter, a choke coil, etc.

[0015] According to another aspect of the present application, the present application provides a device including the magnetic component as described above.

[0016] Optionally, the device includes an automobile.

[0017] According to another aspect of the present application, the present application provides a manufacturing method of a ferrite material, the ferrite material is the ferrite material as described above, and the manufacturing method includes:

[0018] Sinter the formed green body, and the sintering process includes a heating step, a heat preservation step, and a cooling step;

[0019] Among them, the cooling step includes at least one cooling stage, at least one heat preservation stage and at least one re-heating stage, so that the Fe content in the core layer 2+ is different from the Fe content in the shell layer 2+ .

[0020] In a possible implementation, during the sintering process, the oxygen content during the at least one heat preservation stage is controlled to be different from the oxygen content during the heat preservation step

[0021] In a possible implementation, the heating step is sintered in an air atmosphere or a protective atmosphere

[0022] In a possible implementation, the heat preservation step and the cooling step are sintered in a protective atmosphere

[0023] In a possible implementation, the sintering process includes the following steps

[0024] Heating step: heating the ferrite material to a first temperature and controlling the first oxygen content

[0025] Heat preservation step: maintaining the first temperature for a first holding time and controlling the second oxygen content

[0026] Cooling step: cooling the ferrite material from the first temperature to a second temperature and controlling the third oxygen content; maintaining the second temperature for a second holding time and controlling the fourth oxygen content; heating the ferrite material from the second temperature to a third temperature and controlling the fifth oxygen content; maintaining the third temperature for a third holding time and controlling the sixth oxygen content; cooling the ferrite material from the third temperature to a fourth temperature and controlling the seventh oxygen content

[0027] In a possible implementation, in the heating step, the first temperature is 1000-1450 °C and the first oxygen content is the oxygen content in the air

[0028] In a possible implementation, in the heat preservation step, the first temperature is 1000-1450 °C, the first holding time is 0.5-10 h, and the second oxygen content is 0.01-100%

[0029] In a possible implementation, in the cooling step, the second temperature is 10-100 °C lower than the first temperature, and the third oxygen content is controlled by the equilibrium oxygen partial pressure method

[0030] In a possible implementation, in the cooling step, the second holding time is 1-30 min, the fourth oxygen content is 0.01-100%, and the fourth oxygen content is different from the second oxygen content

[0031] In a possible implementation, in the cooling step, the third temperature is 10 - 100 °C higher than the second temperature, and the third temperature is not higher than the first temperature. The fifth oxygen content is controlled by the equilibrium oxygen partial pressure method.

[0032] In a possible implementation, the third holding time is 1 - 30 min, and the sixth oxygen content is 0.01 - 100%;

[0033] And / or, the fourth temperature is not higher than 300 °C, and the seventh oxygen content is controlled by the equilibrium oxygen partial pressure method.

[0034] Compared with the prior art, the technical solution provided by this application can achieve the following beneficial effects:

[0035] The ferrite material and its manufacturing method provided by this application adopt a unique sintering process, which can make the ferrite material have a core-shell structure, and the Fe content in the core layer 2+ and the Fe content in the shell layer 2+ can be different. Different Fe 2+ contents can make the power consumption valley point temperatures (Tsp) of different layers different. Furthermore, it can make the power consumption temperature of the entire ferrite material more evenly distributed, reduce the performance fluctuation of the ferrite material, and make the power consumption stability of the ferrite material higher in a wider temperature range. Therefore, this application controls the power consumption temperature stability of the ferrite through the sintering process, further improving the power consumption stability of the ferrite material.

[0036] The magnetic components and devices of this application include the above-mentioned ferrite material and have all the characteristics and advantages of the above-mentioned ferrite material, which will not be elaborated here.

[0037] It should be understood that the above general description and the following detailed description are only exemplary and do not limit this application. Description of the Drawings

[0038] In order to more clearly illustrate the specific implementation manners of this application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific implementation manners or the prior art. Obviously, the drawings in the following description are some implementation manners of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 Schematic diagram of the power consumption-temperature curve (P-T curve) of the Mn-Zn power ferrite provided for the exemplary implementation manners of this application;

[0040] Figure 2 Schematic diagram of the structure of a ferrite material in the prior art;

[0041] Figure 3 Schematic diagram of the ferrite material structure provided for the exemplary embodiments of the present application;

[0042] Figure 4 Fe provided for the exemplary embodiments of the present application 2+ Compensation K 1 -T curve schematic diagram;

[0043] Figure 5 Schematic diagram of the ferrite material / core structure provided for the exemplary embodiments of the present application;

[0044] Figure 6 For Figure 5 Schematic diagram of the temperature-power consumption curve of the ferrite material shown;

[0045] Figure 7 Graph showing the variation relationship of the sintering temperature and sintering oxygen partial pressure with time in the manufacturing method of the ferrite material provided for the exemplary embodiments of the present application;

[0046] Figure 8 Power consumption-temperature curve graph of the products provided by the examples and comparative examples of the present application.

[0047] Icon:

[0048] 10 - Core layer; 20 - First intermediate layer; 30 - Second intermediate layer; 40 - Shell layer. Detailed implementation manners

[0049] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0050] In the description of the present application, unless otherwise clearly specified and limited, the term "a plurality of" means two or more; the singular forms of "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0051] It should be understood that the term " / " used herein is only a description of the associated relationship of the associated objects, indicating that three relationships may exist, for example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0052] It should be understood that when an element is referred to as being "on" or "under" another element, it can not only be directly connected "on" or "under" the other element, but also be indirectly connected "on" or "under" the other element through an intermediate element. The singular forms "a", "the", and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0053] 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 new technical solutions. Unless otherwise defined or explained, the professional and scientific terms used in this article have the same meanings as those familiar to skilled personnel in the art.

[0054] Those skilled in the art understand that in order to meet the application under a large magnetic field with a higher working frequency or a wider working range and meet the requirements of miniaturization and light weight of the device, the power ferrite material generally requires the following basic characteristics: for example, the saturation magnetic induction intensity Bs should be as high as possible, the core power consumption should be as low as possible within the actual working frequency and working temperature range, and the magnetic permeability should be appropriately high. Among them, power consumption is an important index of the power ferrite material. To ensure the stable, reliable, and efficient operation of the device system, it is necessary to control this important index of the material's power consumption. And there are many factors affecting the power consumption performance of the power ferrite material, such as the material formula, the use of additives or dopants, and the selection of sintering process conditions. In the prior art, in order to improve the power consumption index of the power ferrite material, research is generally carried out from aspects such as selecting preferred raw materials, optimizing the formulation, additives, and powder production technology. There are problems such as high cost, still relatively high power loss at a relatively high temperature (such as 140 °C), and poor power consumption stability in a relatively wide temperature range. For example, the power loss of the current best mass-produced material at 140 °C increases by more than 30% compared to the loss at its valley point temperature. Obviously, the power consumption stability still needs to be improved.

[0055] Therefore, in order to overcome the imperfections of the prior art and further meet the current market demands, the technical solution of the embodiments of the present application provides a ferrite material, its manufacturing method, magnetic element, and device, in order to control or improve the power consumption temperature stability of the ferrite material through the regulation of the sintering process, and further improve the power consumption stability of the current ferrite.

[0056] The types of power ferrite materials can be diverse. Among them, manganese-zinc (MnZn) power ferrite is a relatively common or more widely used power ferrite material, and the superiority of its performance is mainly reflected in the high initial magnetic permeability μ iAnd low loss and good temperature-frequency stability, etc. For the convenience of description, below, the power ferrite materials will be specifically described taking MnZn power ferrite as an example. However, those skilled in the art will understand that other related or similar ferrite materials also have the same or similar problems, and the principle of the present invention can be implemented in any suitable ferrite materials and their manufacturing methods.

[0057] Specifically, the regulation of the sintering process has a great influence on the performance of MnZn ferrite. During the sintering process of MnZn ferrite, a series of physical and chemical changes will occur. Among them, the physical changes mainly include two stages: densification and crystal growth; while the chemical changes are mainly a series of oxidation and reduction reactions, the formation and decomposition of solid solutions, etc. Among them, the chemical changes during the oxidation-reduction process are the most important, and they have the greatest impact on the physical properties of MnZn ferrite.

[0058] Regarding Fe 2 O 3 in ferrite during the sintering process, when heated in air, Fe 2 O 3 with different structures will undergo phase transformation and the transformation of Fe 3+ → Fe 2+ . The reaction process is as follows:

[0059]

[0060] For MnZn ferrite materials, a larger average grain size and an appropriate content of Fe 2+ (divalent iron ions) contribute to improving the power consumption index of the materials. Among them, Fe 2+ mainly affects the magnetocrystalline anisotropy constant K 1 of MnZn ferrite. In order to obtain an appropriate power consumption index at a certain temperature, it is necessary to adjust K 1 → 0 (K 1 approaches 0) near a certain temperature. The content of Fe 2+ will be affected by the sintering conditions. In addition to sintering factors such as sintering temperature and holding time, the sintering atmosphere, especially the oxygen partial pressure or oxygen content in the sintering atmosphere, also has a great influence on the content of Fe 2+ . Generally speaking, the oxygen partial pressure of air is 20.6% (about 20 - 21%). If sintering is carried out in an atmosphere with an oxygen partial pressure lower than this value, it will promote the formation of Fe 2+ , and different oxygen partial pressures will also form Fe 2+ with different concentrations. At the same time, because the ferrite sintering process belongs to a solid-phase reaction process, its reaction time is long and the reaction process is slow. Therefore, by adjusting the oxygen partial pressure and the corresponding time during sintering, the effect of adjusting the Fe 2+ concentration in the product can be achieved.

[0061] Furthermore, generally, as Figure 1 shown, the power loss value of MnZn power ferrite varies with the operating temperature, and there is a minimum value of power loss at a specific temperature. When the temperature is lower or higher than this temperature, the value of power loss gradually increases. The temperature at the lowest point of power consumption on the P-T curve (power consumption - temperature curve) is generally called the valley point temperature (Tsp) of power consumption. For details, reference can be made to Figure 1 shown. This valley point temperature Tsp is crucial for the performance of power ferrite, and the magnitude of Tsp is generally related to the zero-point temperature of the magnetocrystalline anisotropy constant K 1 of ferrite. Therefore, in order to improve the temperature stability of power loss, it is necessary to adjust K 1 to be nearly zero in a wide temperature range.

[0062] Currently, in the prior art, it is generally balanced by adding additives with different positive and negative K 1 values to the formula. For example, Co element is added to power ferrite. Since Co 2+ has a positive magnetocrystalline anisotropy constant K 1 , it can compensate for the ferrite matrix and make K 1 approach zero in a wide temperature range. However, this optimization is limited and cannot be adjusted during the subsequent magnetic core sintering process.

[0063] Based on this, in order to improve the power loss in a wide temperature range and overcome the deficiencies of the prior art, the present application proposes a method based on the principle that different Fe 2+ concentrations can be generated by controlling the oxygen partial pressure during ferrite sintering, and its K 1 is positive, while the K 1 values of most other ions are negative. By utilizing the existing Fe 2+ / Fe 3+ in ferrite and controlling different oxygen partial pressures at different cooling stages, different Fe 2+ concentrations from the center to the outside of the material are finally obtained. Different levels of Tsp are different, and thus the temperature characteristics of the power consumption of the overall ferrite material (such as the magnetic core) show a more average effect, reducing the fluctuation of the magnetic core performance.

[0064] Specifically, Figure 2 shows a schematic structural diagram of an existing ferrite material, which can be an existing toroidal ferrite magnetic core and is prepared by using an existing normal sintering process. As Figure 2 shown, for the obtained product matrix from the inside to the outside, Fe 2+The concentrations are the same, so the final Tsp of the product is fixed, making the slope of the P-T curve (power consumption - temperature curve) of the product larger, that is, the P-T curve is relatively steep.

[0065] Specifically, as Figure 3 shown, in some embodiments, the present application provides a ferrite material, the ferrite material having a core-shell structure and comprising at least a core layer 10 and a shell layer 40;

[0066] The Fe content in the core layer 10 2+ is different from the Fe content in the shell layer 40; the different Fe 2+ contents are obtained through the regulation of the sintering process. 2+ It should be noted that the specific type of the ferrite material in the embodiments of the present application is not limited. The ferrite material may be a power ferrite, further may be a MnZn power ferrite, but is not limited thereto. For example, it may also be a NiZn power ferrite, etc. Those skilled in the art understand that the principle of the present invention can be implemented in any suitable ferrite material. In addition, for clarity and conciseness, descriptions of well-known properties or functions or structures may be omitted.

[0067] Exemplarily, the chemical formula of the ferrite may be

[0068] where Me may be a combination of two or more cations. For example, manganese-zinc ferrite Mn 2+ Zn x Fe (1-x) O 2 , nickel-zinc ferrite Ni 4 Zn x Fe (1-x) O 2 , etc. It can be seen that Fe is in the trivalent state therein. Fe may be oxidized or reduced due to different atmospheres during the high-temperature sintering process of the ferrite. If the atmosphere is reducing, Fe may be changed to the divalent state. For manganese-zinc ferrite, it may become 4 Please refer to shown. Generally, the K of the ferrite matrix is Figure 4 <0. Since the K 1 of Fe 2+ is positive, when the K 1 of the matrix remains unchanged, adjusting the Fe 1 concentration in the product can adjust the temperature of Tsp (θ 2+ ). Therefore, from c it can be known that by regulating the sintering process, adjusting the Fe Figure 4 concentration in the product, especially making the Fe 2+ at different levels 2+Different concentrations make the overall ferrite have a K value in a relatively wide temperature range 1 approach stability and improve the power consumption stability of the material.

[0069] In the embodiment of the present invention, a low-power ferrite material with excellent performance is prepared without adding additives such as Co element, which greatly reduces the cost. At the same time, a unique sintering process is adopted to prepare a ferrite material with a core-shell structure, and the Fe 2+ contents in the core layer and the shell layer are different, and the Tsp values of different layers are different, making the power consumption temperature stability of the overall material more stable and effectively improving the power loss in a wide temperature range.

[0070] It should be noted that the above Fe 2+ content mainly refers to the concentration of Fe 2+ (divalent iron ions), and the concentration of Fe 2+ is different in the core layer and the shell layer. In the embodiment of the present application, the specific concentration of Fe 2+ in the core layer or the shell layer or the ratio of the Fe 2+ concentrations in the core layer and the shell layer are not limited, as long as the two are different and do not limit the purpose of the present invention. The specific content can be adjusted by those skilled in the art according to the actual situation in actual production.

[0071] In some embodiments, the ferrite material further includes an intermediate layer, and the intermediate layer is located between the core layer and the shell layer, and the intermediate layer is one or more layers.

[0072] Specifically, the ferrite material sequentially includes a core layer, an intermediate layer and a shell layer, and the intermediate layer is one or more layers;

[0073] The Fe 2+ content in the core layer, the Fe 2+ content in the intermediate layer and the Fe 2+ content in the shell layer are all different. Among them, the Fe 2+ contents in different intermediate layers can be the same or different.

[0074] It can be understood that the ferrite material can have a core-shell structure, can have a layer-by-layer structure from the inside to the outside or from the center to the outside, can be composed of a core layer and a shell layer from the inside to the outside, or can be composed of a core layer, an intermediate layer and a shell layer from the inside to the outside. That is, the ferrite material can at least include a core layer and a shell layer, having a two-layer structure, or can include a core layer, an intermediate layer and a shell layer, having a structure with more than two layers, and the Fe 2+ concentrations in different layers are different, which can make the stability of power consumption higher in a relatively wide temperature range.

[0075] It should be noted that the specific number of layers included in the ferrite material in the embodiments of the present application is not limited, and can be adjusted according to the application temperature range, frequency range, or actual application requirements. Exemplarily, the ferrite material may include a core layer and a shell layer, presenting a two-layer structure; or, the ferrite material may include a core layer, an intermediate layer, and a shell layer, where the intermediate layer is one layer, and the material presents a three-layer structure; or, the ferrite material may include a core layer, an intermediate layer, and a shell layer, where the intermediate layer is two layers, and the material presents a four-layer structure; furthermore, for example, the intermediate layer may also be three layers, four layers, five layers, etc.

[0076] In some embodiments, the Fe 2+ content shows a gradient distribution in the core layer, the intermediate layer, and the shell layer. For example, the Fe 2+ concentration shows a gradually decreasing trend from the core layer, through the intermediate layer, to the shell layer; or, the Fe 2+ concentration shows a gradually increasing trend from the core layer, through the intermediate layer, to the shell layer; that is, the Fe 2+ concentration can gradually decrease or gradually increase from the inner layer to the outer layer. Furthermore, the Fe 2+ concentration can show a non-uniform gradient increase from the core layer, through the intermediate layer, to the shell layer (from the inner layer to the outer layer).

[0077] Thus, it is convenient to regulate, and a simple adjustment of the lowest temperature of power consumption can be achieved, which is more conducive to improving the stability of power consumption in a relatively wide temperature range.

[0078] Exemplarily, the ferrite material can be made into a magnetic core, which can include a core layer, an intermediate layer, and a shell layer, and can be a layered structure with different Fe 2+ concentrations from the center to the outside. For example, as Figure 5 shown, the magnetic core can be a four-layer structure, which can be successively the core layer 10, the first intermediate layer 20, the second intermediate layer 30, and the shell layer 40 from the inside to the outside, and the Fe 2+ concentration in each layer is different.

[0079] Figure 6 Shows Figure 5 the temperature-power consumption curve (T-P curve) diagram of the ferrite material shown in Figure 5 and Figure 6 . Referring to 2+ and 2+ , it can be seen that the Fe 2+ concentrations in the core layer 10, the first intermediate layer 20, the second intermediate layer 30, and the shell layer 40 are all different, that is, the Fe 2+ concentration in each layer is different, so that the T-P curve of each layer is also different, and the valley point temperatures Tsp in the T-P curves of the core layer 10, the first intermediate layer 20, the second intermediate layer 30, and the shell layer 40 all exist and are also different. Figure 6The synthetic curve in [it] represents the T-P curve of the overall material, i.e., the obtained product. It can be seen that compared with the T-P curves of the core layer 10, the first intermediate layer 20, the second intermediate layer 30, and the shell layer 40, the synthetic T-P curve is smoother or flatter. That is, the temperature characteristics of the power consumption of the overall magnetic core show a more average effect, reducing the fluctuations in the magnetic core performance. As a result, the power consumption of the magnetic core product can remain stable within a relatively wide temperature range.

[0080] From this, it can be seen that for the ferrite material provided by the embodiments of the present application, the synthetic curve (the T-P curve of the product) has a higher power consumption stability within the range of 40 - 100 °C or even 20 - 140 °C.

[0081] In some embodiments, the present application also provides a magnetic component, and the material for manufacturing the magnetic component includes the aforementioned ferrite material.

[0082] The ferrite material provided by the embodiments of the present application can be made into a magnetic core, or the material for manufacturing the magnetic core can include the ferrite material provided by the embodiments of the present application. For the convenience of description, the embodiments of the present application mainly take the ferrite material made into a magnetic core as an example to specifically elaborate on the ferrite material, its preparation method, and the magnetic component. However, those skilled in the art will understand that the principle of the present invention can be implemented in any appropriate product.

[0083] Optionally, the magnetic core component can be a magnetic component that needs to work properly within a relatively wide temperature range.

[0084] Specifically, the magnetic component can be an inductor, a transformer, a filter, a choke coil, etc. It should be understood that the magnetic component can be a magnetic component using the ferrite material provided by the embodiments of the present application. The present application does not make special limitations on the specific type of the magnetic component. The magnetic component can be implemented in various forms, including but not limited to inductors, transformers, filters, or choke coils, etc., and can also include newly developed magnetic components.

[0085] In some embodiments, the present application also provides a device, and the device includes the aforementioned magnetic component.

[0086] Optionally, the device can be an automobile, and further can be a smart automobile, but it is not limited thereto. The device can also be other electronic devices or power / electrical devices, etc. The embodiments of the present application do not limit the specific type of the device.

[0087] Taking the device as an automobile as an example to specifically elaborate on the effects that the device can achieve. However, those skilled in the art understand that based on the same inventive principle, similar devices can also achieve the same or similar effects.

[0088] The device provided by this application, such as in a smart car, usually requires a large number of electronic devices (magnetic components) containing soft ferrite. These electronic devices need to work properly within a wide temperature range. Conventional soft ferrite generally achieves the effect of less change in magnetic properties within a wide temperature range by adding elements such as Co to make the material. However, it has the defects of high cost, the inability to completely eliminate the existence of Tsp, and difficulty in further optimization during the sintering process. Through the setting of a special sintering process, especially through the control of the distribution atmosphere and temperature during the sintering process, the present invention obtains a ferrite structure with different Tsps that is hierarchically distributed in structure. The lowest Tsp of power consumption for each layer is different. Ultimately, the overall effect can make the power consumption of the magnetic core remain stable within a wide temperature range, thereby improving the power loss within the wide temperature range and ensuring the stability requirements of the electronic devices applied in smart cars.

[0089] In some embodiments, this application also provides a manufacturing method for a ferrite material. The ferrite material is the aforementioned ferrite material, and the manufacturing method includes:

[0090] Sintering the formed green body. The sintering process includes a heating step, a heat preservation step, and a cooling step;

[0091] Among them, the cooling step includes at least one cooling stage, at least one heat preservation stage (heat preservation platform), and at least one re-heating stage, such that the Fe 2+ content in the core layer is different from the Fe 2+ content in the shell layer.

[0092] By setting at least one heat preservation stage, i.e., a heat preservation platform, in the cooling step during the sintering process, this method adjusts the degree of oxidation of the material, that is, regulates the Fe 2+ concentration obtained after the solid-phase reaction of the ferrite, so that the Fe 2+ concentrations of different layers are different, and the Tsps of different layers are different. It can compensate for K 1 for the ferrite matrix, making the overall K 1 of the ferrite material approach stability and improving the power consumption stability of the material. Moreover, this method prepares a ferrite material with low power consumption and excellent performance without adding additives such as Co elements, greatly reducing the cost, making the power consumption temperature stability of the material as a whole more stable, effectively improving the power loss within a wide temperature range, meeting the usage requirements of existing magnetic components, and having a wide application prospect.

[0093] Figure 7Shows the relationship diagrams of sintering temperature and sintering oxygen partial pressure versus time. Among them, the solid line part is the sintering temperature curve (the curve of sintering temperature versus time), that is, the temperature control change curve of the kiln furnace during the sintering process as time goes by; the dotted line part is the sintering oxygen partial pressure curve (the curve of sintering oxygen partial pressure versus time), that is, the change curve of the oxygen partial pressure in the kiln furnace as time goes by during the sintering process. From Figure 7 It can be seen that in the process of preparing this ferrite material, a unique sintering process is adopted. In the cooling step during the sintering process, at least one cooling stage, at least one heat preservation stage (heat preservation platform), and at least one re-heating stage are set, and the oxygen partial pressure in each stage is regulated. Different oxygen partial pressures can form different concentrations of Fe inside the product 2+ . Thus, in the embodiment of the present invention, by setting multiple heat preservation platforms at the traditional cooling end, and controlling the temperature, heat preservation time, and oxygen partial pressure or oxygen content value of each platform, a layered structure similar to that in the aforementioned product containing different concentrations of Fe can be formed 2+ .

[0094] It should be noted that as mentioned above, the specific number of layers of the ferrite material in the embodiment of the present application is not limited, and can be adjusted according to the application temperature range, frequency range, or actual application requirements. Correspondingly, in the cooling step during the sintering process in the embodiment of the present application, the number of cooling stages, the number of heat preservation stages, and the number of re-heating stages are not specifically limited. Among them, the cooling stage can be 1 time, 2 times, 3 times, 4 times or more, etc., the heat preservation stage, that is, the heat preservation platform, can be set to 1, 2, 3, 4 or more, etc., and the re-heating stage can be 1 time, 2 times, 3 times, 4 times or more, etc. It should be understood that Figure 7 The number of heat preservation platforms, the number of cooling stages, etc. shown in the cooling step are only exemplary and do not constitute a specific limitation on the cooling step. In other embodiments of the present application, the number of heat preservation platforms, the number of cooling stages, etc. can include more or fewer numbers than shown in the figure, or different heat preservation temperatures and heat preservation times. In actual applications, they can be adjusted according to the actual process conditions or product requirements.

[0095] In some embodiments, the manufacturing method of the ferrite material includes the following steps:

[0096] a), Preparation of raw materials, batching, and preparation of powder materials;

[0097] b), Molding: The powder material can be molded into a green body (blank) with a specific shape by a powder molding machine;

[0098] c), Sintering: Sinter the green body, and the sintering process includes a heating step, a heat preservation step, and a cooling step;

[0099] Among them, the temperature reduction step includes at least one temperature reduction stage, at least one heat preservation stage, and at least one re-heating stage;

[0100] d), post-treatment.

[0101] It should be understood that the embodiments of the present application do not limit the specific operations of the above steps a), b), and d), and conventional operation processes in the art can be adopted, which will not be elaborated here.

[0102] Exemplarily, the raw materials in step a) may include 50-60% (mole content) of Fe 2 O 3 , 5-25% (mole content) of ZnO, and the remaining components are manganese-zinc ferrite pellets of MnO; in addition, trace additives can also be added as needed. The shape of the green body in step b) can be set to any shape according to the actual product requirements, such as an annular shape or a similar shape. The post-treatment in step d) may include post-treatment processes such as grinding, cutting, or spraying. The sintered material is processed by grinding, cutting, or spraying according to requirements to obtain the final product.

[0103] In some embodiments, regarding the sintering process of step c): Among them, the oxygen content during at least one heat preservation stage is controlled to be different from the oxygen content during the heat preservation step, or the oxygen partial pressure during at least one heat preservation stage is controlled to be different from the oxygen partial pressure during the heat preservation step. Thus, it helps to form a layered structure similar to that in the aforementioned product containing different concentrations of Fe 2+ .

[0104] Therefore, by controlling the oxidation degree of the material in different stages, the Fe 2+ concentration inside the material can be controlled. Different oxygen partial pressures can form different concentrations of Fe 2+ inside the product, so that a layered structure similar to that in the aforementioned product containing different concentrations of Fe 2+ can be formed.

[0105] Specifically, in some embodiments, regarding the sintering process of step c): The heating step can be sintered in an air atmosphere or a protective atmosphere, that is, the sintering atmosphere in the heating step can be air or a protective atmosphere.

[0106] The heat preservation step and the temperature reduction step are sintered in a protective atmosphere, that is, the sintering atmosphere in the heat preservation step and the temperature reduction step can be a protective atmosphere.

[0107] Optionally, the protective atmosphere can be a protective gas well-known or commonly used in the art such as nitrogen or argon. The embodiments of the present application do not limit the specific type of the protective atmosphere.

[0108] It should be noted that in this article, the oxygen content or oxygen partial pressure involved is calculated by volume. For example, if the oxygen content is 20.6%, it can be expressed as 20.6 vol.%. For the convenience of description, this article mainly describes it in the form of 20.6% in an abbreviated form.

[0109] Furthermore, in some embodiments, the sintering process includes the following steps:

[0110] Heating step: The ferrite material is heated from room temperature to a first temperature, sintered in an air atmosphere during this period, and the first oxygen content is controlled; wherein, the first temperature can be 1000 - 1450 °C, the first oxygen content is the oxygen content in the air (the oxygen content is about 20.6%), and the heating time can be 3 - 30 h.

[0111] Insulation step: Maintain a first holding time at the first temperature, sinter in a protective atmosphere during this period, and control the second oxygen content; wherein, the first temperature can be 1000 - 1450 °C, the first holding time can be 0.5 - 10 h, and the second oxygen content can be 0.01 - 100%.

[0112] It should be noted that the first temperature in the above heating step and the first temperature in the insulation step can be the same or different. For example, in this insulation step, a slight increase in temperature can also be carried out to reach the final first temperature. There is no limit to the heating rate of the above heating. For example, the heating rate can be 1 - 3 °C / min.

[0113] Cooling step: The ferrite material is cooled from the first temperature to a second temperature, sintered in a protective atmosphere during this period, and the third oxygen content is controlled; wherein, the second temperature is 10 - 100 °C lower than the first temperature, and the third oxygen content is controlled by the equilibrium oxygen partial pressure method during this period;

[0114] Maintain a second holding time at the second temperature, sinter in a protective atmosphere during this period, and control the fourth oxygen content; wherein, the second holding time is 1 - 30 min, the fourth oxygen content is 0.01 - 100%, and the fourth oxygen content is different from the second oxygen content;

[0115] The ferrite material is heated from the second temperature to a third temperature, sintered in a protective atmosphere during this period, and the fifth oxygen content is controlled; wherein, the third temperature is 10 - 100 °C higher than the second temperature, and the third temperature is not higher than the first temperature. The heating rate can be 1 - 3 °C / min, and the fifth oxygen content is controlled by the equilibrium oxygen partial pressure method during this period;

[0116] Maintain a third holding temperature for a third holding time, during which sintering is carried out in a protective atmosphere to control the sixth oxygen content; wherein, the third holding time is 1 - 30 min, and during this period, the sixth oxygen content is controlled by the equilibrium oxygen partial pressure method, and / or, the sixth oxygen content is 0.01 - 100%, and the sixth oxygen content can be different from the above-mentioned fourth oxygen content and second oxygen content;

[0117] Cool the ferrite material from the third temperature to the fourth temperature, during which sintering is carried out in a protective atmosphere to control the seventh oxygen content; wherein, the fourth temperature is not higher than 300 °C, and during this period, the fifth oxygen content can be controlled by the equilibrium oxygen partial pressure method.

[0118] It can be understood that in the final cooling stage of the sintering process, the temperature needs to be reduced to below 300 °C. For example, it can be reduced to 300 °C, reduced to 250 °C, or reduced to 200 °C, etc. And before this final cooling stage, there can also be multiple heat preservation stages, cooling stages, and reheating stages. That is, the final temperature is not limited to the fourth temperature, but can be the sixth temperature, the eighth temperature, etc.

[0119] The cooling stage and the reheating stage in the above-mentioned cooling step can be sintered in an atmosphere of equilibrium oxygen partial pressure. That is, the oxygen content in the cooling stage and the reheating stage of the cooling step can be controlled by the equilibrium oxygen partial pressure method, that is, the oxygen content is adjusted according to the equilibrium oxygen partial pressure theory, and the oxygen content can obtain the corresponding oxygen content through the equilibrium relationship between temperature and oxygen content, that is, the equilibrium oxygen partial pressure relationship formula.

[0120] It can be understood that the above-mentioned sintering process is only exemplary. In some other embodiments of the present application, after the above steps, the sintering process can also include the fifth temperature, the fourth holding time, the eighth oxygen content, etc. That is, the number of heat preservation platforms, the number of cooling stages, and the number of reheating stages can be more or less than the above-mentioned sintering process. In practical applications, it can be adjusted according to the actual process conditions or product requirements, and will not be described in detail here.

[0121] The manufacturing method of the ferrite material can achieve a simple adjustment of the lowest power consumption temperature, with simple operation, easy implementation, and easy to realize large-scale production. Particularly prominent is that this manufacturing method adopts a step-by-step heat preservation and cooling sintering process. In the cooling step of sintering, it includes multiple steps of heat preservation and step-by-step control of the oxidation degree, which can make the oxidation degree inside and outside the ferrite material correspond to the oxidation degree required by the lowest power consumption temperature, and finally realize that the Fe 2+ concentration shows a certain gradient distribution from the inside to the outside.

[0122] Therefore, for the product obtained by this manufacturing method, the Fe 2 + concentration can show different concentrations from the entity center to the surface, and the Fe 2+For different power consumption valley point temperatures, the temperature characteristics of the overall ferrite material (such as magnetic cores) present a more average effect, effectively improving the power consumption temperature stability of the ferrite material within a wide temperature range.

[0123] It should be understood that the content not described in detail in the above ferrite material, its manufacturing method and application are all common parameters or conventional operation methods that are easily conceivable by those skilled in the art. They can refer to the prior art or be adjusted by those skilled in the art according to the actual situation. Therefore, the detailed description thereof can be omitted.

[0124] Specifically, the effects of the present invention will be described below in conjunction with specific examples and comparative examples, but the protection scope of the present invention is not limited by the following examples.

[0125] Example

[0126] S1: Prepare manganese-zinc ferrite granulated materials, and their performance only needs to be equivalent to that of TDK PC95.

[0127] S2: Dry press and form into a green ring blank with an outer diameter of 29.6 mm, an inner diameter of 17.78 mm, and a height of 9.48 mm, and the density of the green blank is 2.85 g / cm 3 .

[0128] S3: Put the green blank into a sintering furnace that can be protected by atmosphere for sintering, and the sintering curve is as follows.

[0129] Specifically, the sintering process includes:

[0130] a) Heat up to 1000 °C at a rate of 2 °C / min, and the oxygen content is 20.6% (air sintering) during this period;

[0131] b) Heat up to 1375 °C at a rate of 1.5 °C / min and hold for 4 h, and control the oxygen content to be 6% during this period;

[0132] c) Cool down to 1300 °C at a rate of 2.5 °C / min, and the oxygen content is calculated according to lg(P O2 ) = 8.9 - 13385 / T, where T is the temperature;

[0133] d) Hold at 1300 °C for 10 min, and control the oxygen content to be 2.5% during this period;

[0134] e) Heat up to 1345 °C at a rate of 2 °C / min, and the oxygen content is calculated according to lg(P O2 ) = 8.95 - 13385 / T, where T is the temperature; then hold for 30 min, and the oxygen content is 4.77% during the holding period; then cool down to 1200 °C at a rate of 2.5 °C / min, and the oxygen content is calculated according to lg(P O2 ) = 8.95 - 13385 / T, where T is the temperature;

[0135] f) Hold at 1200 °C for 10 min, controlling the oxygen content to be 0.73% during this period;

[0136] g) Heat up to 1325 °C at a rate of 2 °C / min, during which the oxygen content follows lg(P O2 ) = 9 - 13385 / T, where T is the temperature; then hold for 30 min, and the oxygen content is 4.2% during the holding period;

[0137] f) Cool down to 200 °C at a rate of 3 °C / min, during which the oxygen content follows lg(P O2 ) = 9 - 13385 / T, where T is the temperature;

[0138] h) Test the product after it is taken out of the furnace.

[0139] The test results are shown in Table 1 and Figure 8 as follows.

[0140] Comparative Example

[0141] S1: Prepare manganese-zinc ferrite granular materials, and their performance only needs to be equivalent to that of TDK PC95.

[0142] S2: Dry press and form into a green ring blank with an outer diameter of 29.6 mm, an inner diameter of 17.78 mm, and a height of 9.48 mm, and the green blank density is 2.85 g / cm 3 .

[0143] S3: Put the green blank into a sintering furnace with atmosphere protection for sintering, and the sintering curve is as follows.

[0144] Specifically, the sintering process includes:

[0145] a) Heat up to 1000 °C at a rate of 2 °C / min, and the oxygen content is 20.6% (air sintering) during this period;

[0146] b) Heat up to 1375 °C at a rate of 1.5 °C / min and hold for 4 h, and the oxygen content is 6% during this period;

[0147] c) Cool down to 1300 °C at a rate of 2.5 °C / min, and the oxygen content follows lg(P O2 ) = 8.9 - 13385 / T, where T is the temperature;

[0148] d) Cool down to 200 °C at a rate of 3 °C / min, and the oxygen content follows lg(P O2 ) = 8.9 - 13385 / T, where T is the temperature;

[0149] e) Test the product after it is taken out of the furnace

[0150] The test results are shown in Table 1 and Figure 8as shown

[0151] Table 1 Product test results of examples and comparative examples

[0152]

[0153] From Table 1 and Figure 8 it can be seen that through the comparative analysis of the test data of the examples and the comparative examples, the power consumption difference of the product provided by the examples of the present application is 71.7 mW / cm 3 , while the power consumption difference of the product of the comparative example reaches 105 mW / cm 3 , and the power consumption fluctuation of the comparative example is relatively large in a wide temperature range. Thus, it shows that the technical solution of the present application can make the magnetic properties of the magnetic element change less in a wide temperature range, and improve the power consumption stability of the magnetic element in a wide temperature range.

[0154] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0155] It should be noted that a part of this patent application document contains content protected by copyright. The copyright owner reserves the copyright except for making copies of the patent document content of the patent office's patent documents or records.

Claims

1. A manufacturing method of a ferrite material, characterized in that, the manufacturing method includes: sintering the formed green body to obtain a ferrite material, the ferrite material having a core-shell structure and at least including a core layer and a shell layer, and the sintering process includes a heating step, a heat preservation step, and a cooling step; Among them, the temperature reduction step includes at least one temperature reduction stage, at least one heat preservation stage, and at least one re-heating stage, so that the Fe content in the core layer 2+ is different from the Fe content in the shell layer 2+ content; the re-heating temperature of the ferrite material in the cooling step is not higher than the temperature in the heat preservation step.

2. The manufacturing method of the ferrite material according to claim 1, characterized in that, during the sintering process, the oxygen content during at least one heat preservation stage is controlled to be different from the oxygen content during the heat preservation step.

3. The manufacturing method of the ferrite material according to claim 1, characterized in that, the heat preservation step and the cooling step are sintered in a protective atmosphere.

4. The manufacturing method of the ferrite material according to any one of claims 1-3, characterized in that, the sintering process includes the following steps: Heating step: heating the ferrite material to a first temperature and controlling the first oxygen content; Heat preservation step: maintaining the first holding time at the first temperature and controlling the second oxygen content; Cooling step: cooling the ferrite material from the first temperature to a second temperature and controlling the third oxygen content; maintaining the second holding time at the second temperature and controlling the fourth oxygen content; heating the ferrite material from the second temperature to a third temperature and controlling the fifth oxygen content; maintaining the third holding time at the third temperature and controlling the sixth oxygen content; cooling the ferrite material from the third temperature to a fourth temperature and controlling the seventh oxygen content.

5. The manufacturing method of the ferrite material according to claim 4, characterized in that, in the heating step, the first temperature is 1000-1450 °C and the first oxygen content is the oxygen content in the air.

6. The manufacturing method of the ferrite material according to claim 4, characterized in that, in the heat preservation step, the first temperature is 1000-1450 °C, the first holding time is 0.5-10 h, and the second oxygen content is 0.01-100%.

7. The manufacturing method of the ferrite material according to claim 4, characterized in that, in the cooling step, the second temperature is 10-100 °C lower than the first temperature, and the third oxygen content is controlled by the method of balanced oxygen partial pressure.

8. The manufacturing method of the ferrite material according to claim 4, characterized in that, in the cooling step, the second holding time is 1-30 min, the fourth oxygen content is 0.01-100%, and the fourth oxygen content is different from the second oxygen content.

9. The manufacturing method of the ferrite material according to claim 4, characterized in that, in the cooling step, the third temperature is 10-100 °C higher than the second temperature and the third temperature is not higher than the first temperature, and the fifth oxygen content is controlled by the method of balanced oxygen partial pressure.

10. The manufacturing method of the ferrite material according to claim 4, characterized in that, the third holding time is 1-30 min and the sixth oxygen content is 0.01-100%; and / or, the fourth temperature is not higher than 300 °C, and the seventh oxygen content is controlled by the method of balanced oxygen partial pressure.

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