A double-ferrite three-layer hetero-sintering body material, a preparation method and applications thereof

Abstract

The application belongs to the field of co-fired body materials, and discloses a double-ferrite three-layer hetero co-fired body material and a preparation method thereof. The double-ferrite three-layer hetero co-fired body material comprises an intermediate layer ferrite and upper and lower two layers of ferrite. The intermediate layer ferrite is a YIG system microwave ferrite, and the upper and lower two layers of ferrite are both NiZn system ferrites doped with Bi2O3. The three layers of ferrite are combined by co-firing. The application further provides a preparation method and application of the double-ferrite three-layer hetero co-fired body material. The application solves the technical problems that the NiZn system ferrite and the YIG system microwave ferrite of the plane contact type are not matched in sintering temperature and shrinkage characteristics, the layered hetero co-fired body is prone to co-firing mismatch, and the combination interface is not tight, ion diffusion at the interface and electromagnetic performance degradation of the material.

Description

Technical Field

[0001] This invention belongs to the field of co-fired materials, and more specifically, relates to a double ferrite triple-layer heterogeneous co-fired material, its preparation method, and its application. Background Technology

[0002] With the rapid development of technologies such as wireless communication, radar detection, and electronic countermeasures, microwave devices are continuously evolving towards miniaturization, integration, high frequency, and multifunctionality. Among these advancements, heterogeneous co-firing technology, as a crucial approach to achieving microwave device integration, has received widespread attention in recent years. Ferrite materials, due to their excellent gyromagnetic properties, high resistivity, and good temperature stability, play an irreplaceable role in microwave devices. NiZn-based ferriferrites, belonging to the spinel-type ferrimagnetic oxide family, possess advantages such as high resistivity, high saturation magnetization, and a wide tunable permeability range. In contrast, YIG-based microwave ferriferrites, being garnet-type ferrimagnetic materials, exhibit narrow ferromagnetic resonance linewidth, low high-frequency loss, and excellent microwave dielectric and magnetic properties. These two types of ferrite materials are often heterogeneously co-fired. The sintering temperature of pure YIG materials is generally higher than 1400 ℃, significantly higher than that of NiZn materials. This further complicates the matching of their shrinkage characteristics during heterogeneous co-firing.

[0003] Current research has explored the use of core-ring structured heterogeneous co-fired substrates. For example, CN121709897A discloses a core-ring structured heterogeneous co-fired composite substrate of YIG-based ferrite and NiZn-based ferrite, with Cu²⁺ as the central ferrite. + Ion-substituted NiZn-based ferrites with an outer nested ferrite of Bi³⁺ + Ion-substituted YIG-based microwave ferrites are used to lower the sintering temperature of YIG. However, this core-ring nested structure cannot be applied in non-core-ring structure scenarios with higher requirements, such as planar contact heterogeneous co-fired bodies. In this type of heterogeneous co-fired body, the requirements for matching the shrinkage rates of the two heteromaterials are more stringent. Any mismatch in shrinkage rates can easily lead to defects such as warping, cracking, or poor interfacial bonding.

[0004] The development of planar contact heterogeneous co-fired bodies mainly faces the following key technical challenges: first, matching the shrinkage characteristics between heterogeneous co-fired materials; second, achieving tight bonding at the heterogeneous co-fired interface and controlling ion diffusion at the interface. Solving these problems simultaneously is quite difficult. Existing technologies include doping NiZn-based ferrites with Cu²⁺. + To regulate its shrinkage rate, but some literature points out that Cu² + The incorporation of Cu² will cause lattice distortion, and Cu² + Replace Fe³ +This significantly affects the electromagnetic properties of NiCuZn ferrite (see Zhao Teji, Zhang Huaiwu, Su Hua. Influence of Cu content on the electromagnetic properties of NiCuZn ferrite materials [J]. Magnetic Materials and Devices, 2006, (02): 46-48.). Therefore, Cu² alone... + Doping makes it difficult to achieve shrinkage matching, avoid warpage and cracking, ensure the controllability of ion diffusion at the interface, and maintain the excellent electromagnetic properties of ferrite materials.

[0005] Therefore, it is evident that the existing technology still lacks a solution for heterogeneous co-fired materials in the field of non-core-ring structures that can effectively balance shrinkage matching, interfacial bonding quality, and maintenance of material electromagnetic properties. Summary of the Invention

[0006] To address the above-mentioned deficiencies or improvement needs of existing technologies, this invention provides a double ferrite triple-layer heterogeneous co-fired material and its preparation method. This solves the technical problem that due to the difference in sintering temperature and the mismatch in shrinkage characteristics between NiZn-based ferrite and YIG-based microwave ferrite for planar contact, the multilayer heterogeneous co-fired material is prone to co-firing mismatch, which in turn leads to loose bonding interfaces (such as warping and cracking), ion diffusion at the interface, and deterioration of the material's electromagnetic properties.

[0007] To achieve the above objectives, according to one aspect of the present invention, a dual-ferrite triple-layer heterogeneous co-fired material is provided, comprising an intermediate ferrite layer and upper and lower ferrite layers, wherein the intermediate ferrite layer is a YIG-based microwave ferrite, and the upper and lower ferrite layers are NiZn-based ferrites doped with Bi2O3, and the intermediate ferrite layer and the upper and lower ferrite layers are co-fired composites.

[0008] Preferably, the amount of Bi2O3 incorporated into the NiZn ferrite material is c wt%, 0.0 <c ≤ 1.0。

[0009] Preferably, the YIG-based microwave ferrite of the intermediate ferrite layer is Y... 2.8-a Bi a Al 0.2 Fe5O 12 , 0.0 The general chemical formula of the NiZn-based ferrite in the upper and lower ferrite layers is Ni 1-b Zn b Fe2O4, 0.2 ≤ b ≤ 0.4.

[0010] According to another aspect of the present invention, a method for preparing the above-mentioned double ferrite triple-layer heterogeneous co-fired material is also provided, comprising the following steps: ​(1) Preparation of NiZn-based and YIG-based ferrite granulation powders: Using NiO powder, ZnO powder, Fe2O3 powder, Bi2O3 powder, Y2O3 powder, and Al2O3 powder as raw materials, respectively according to the chemical formula Ni 1-b Zn b Fe2O4 and Y 2.8-a Bi a Al 0.2 Fe5O 12 The raw materials were mixed according to the nominal chemical ratio of the metal elements to form NiZn-based ferrite mixed powder and YIG-based ferrite mixed powder. The two mixed powders were then subjected to a second wet ball milling process to obtain NiZn-based ferrite granulated powder and YIG-based ferrite granulated powder, respectively. A certain amount of Bi was used in the process. 3+ Ions and Al 3+ Together they replace the Y in YIG-based ferrites 3 + Ions, reducing its sintering temperature range to 1125 - 1225 ℃; where, 0.0 (2) Regulation of shrinkage characteristics of NiZn ferrite: The NiZn ferrite granulation powder obtained above was added to a set amount of Bi2O3 and mixed evenly; (3) Forming of the green body of the double ferrite triple-layer heterogeneous co-fired material: The granulated powder obtained in step (2) is placed into the mold and pressed to obtain the first layer of NiZn ferrite cylindrical green body, and the YIG ferrite granulated powder obtained in step (1) is added to the first layer of NiZn ferrite cylindrical green body to prepare the second layer of YIG ferrite layer. The granulated powder obtained in step (2) is added to the second layer of YIG ferrite layer and pressed to obtain the third layer of NiZn ferrite layer, thus obtaining the NiZn-YIG-NiZn ferrite stacked composite green body; (4) Sintering of NiZn-YIG-NiZn ferrite stacked co-fired body: The NiZn-YIG-NiZn ferrite stacked composite green body obtained in step (3) is sintered to obtain a double ferrite triple stacked heterogeneous co-fired body material.

[0011] Preferably, in step (3), the pressure during pressing is 150~200 MPa, and the holding time is 30~60 s.

[0012] Preferably, in step (4), the sintering temperature is 1150 ~ 1200 ℃, and the holding time is 4 ~ 6 h.

[0013] According to another aspect of the present invention, the application of the above-mentioned dual ferrite material stacked heterogeneous co-fired body in the field of filters and circulators is also provided.

[0014] ​In summary, compared with the prior art, the technical solutions conceived by this invention have the following main advantages: 1. The double ferrite triple-layer heterogeneous co-fired body provided by this invention uses YIG-based ferrite as the intermediate layer and NiZn-based ferrite as the upper and lower layers. NiZn ferrite is doped with Bi2O3 and prepared through co-firing. This effectively controls the sintering shrinkage behavior of the NiZn ferrite layer, achieving a high match between the shrinkage rate and shrinkage ratio of the NiZn ferrite layer and the YIG-based ferrite intermediate layer. This results in a tightly bonded double ferrite triple-layer heterogeneous co-fired body free from warping and cracking. Furthermore, the NiZn-YIG-NiZn triple-layer structure effectively suppresses Fe³⁺ in the upper and lower NiZn ferrite layers. + Ions diffuse into the intermediate layer, thereby reducing Fe³⁺. + The adverse effects of ions on the electromagnetic properties of the intermediate microwave dielectric layer. The tightly bonded microscopic heterogeneous interfaces and clearly defined elemental distributions confirm extremely low ion interdiffusion. Furthermore, the doping of Bi into the NiZn-based ferrite... 3+ The ions basically do not enter the crystal lattice of NiZn-based ferrites, which is conducive to maintaining the excellent electromagnetic properties of NiZn-based ferrites.

[0015] 2. The double ferrite triple-layer heterogeneous co-fired body provided by the present invention, by doping Bi2O3 into NiZn-based ferrite, utilizes the adjustment effect of the shrinkage characteristics of NiZn-based ferrite when the Bi2O3 doping amount increases from 0 wt% to 1.0 wt%, significantly improving the shrinkage performance of NiZn-based ferrite within this doping range, so that it is basically matched with the shrinkage characteristics of YIG-based ferrite, thereby realizing the multilayer co-firing of NiZn-based ferrite and YIG, and obtaining a heterogeneous co-fired body with tight bonding, minimal warpage or even no warpage cracking.

[0016] 3. The double ferrite triple-layer heterocomposite provided by this invention has excellent dielectric properties and low high-frequency loss, with the general chemical formula Y0. 2.8-a Bi a Al 0.2 Fe5O 12 (0.0) 1-b Zn b Using NiZn-based ferrites of Fe2O4 (0.2 ≤ b ≤ 0.4) as the upper and lower layers, based on a stacked heterogeneous co-fired structure, the electromagnetic performance advantages of the two types of ferrite materials are complementary, which can synergistically meet the needs of multi-functional integration such as circulation and filtering.

[0017] ​4. This invention uses a co-pressing molding process that eliminates the need for an additional intermediate buffer layer or special sintering equipment. The process steps are simple and reliable, and it maintains excellent electromagnetic performance. It can be used to fabricate devices for different application scenarios, such as filters and circulators, which is beneficial for the multi-functionality and integration of devices. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the method for preparing NiZn-YIG-NiZn ferrite triple-layer sample in an embodiment of the present invention; Figure 2 The graph shows the shrinkage rate and shrinkage rate change of YIG ferrite and NiZn ferrite prepared according to the preparation methods of Comparative Examples 1-3 and Examples 1-2; where... Figure 2 In the diagram, (a) corresponds to the change in temperature corresponding to the shrinkage rate; Figure 2 (b) in the figure corresponds to the change in the rate of change of the shrinkage rate with temperature; Figure 3 The XRD patterns of YIG ferrite and NiZn ferrite prepared according to the preparation methods of Comparative Examples 1-3 and Examples 1-2 are shown; Figure 3 (a) shows the XRD patterns of YIG ferrites in Comparative Examples 1-3 and the XRD patterns of NiZn ferrites in Comparative Examples 1 and 3, where Figure 3 (b) XRD patterns of NiZn-YIG-NiZn ferrite triple-layer heterogeneous co-fired bodies corresponding to Examples 1-2; Figure 4 Images of NiZn-YIG-NiZn ferrite triple-layer heterogeneous co-fired samples from Comparative Examples 1-3 and Examples 1-2 are shown; Figure 4 (a) in the figure corresponds to the actual object in Scale 1. Figure 4 (b) in the figure corresponds to the physical object of Example 1. Figure 4 (c) in the figure corresponds to the physical object diagram of Example 2. Figure 4 (d) in the figure corresponds to the physical object in scale 2. Figure 4 (e) in the figure corresponds to the physical image in scale 3; Figure 5 The images show a cross-sectional view of the NiZn-YIG-NiZn trilaminar heterocopolymer prepared in Example 1 after polishing and an SEM image of the heterostructure interface; wherein... Figure 5 (a) in the diagram corresponds to a cross-sectional view. Figure 5 (b) in the image corresponds to the SEM image of the heterojunction interface between YIG ferrite and NiZn ferrite (NZF); Figure 6 The images show the SEM image and elemental EDS mapping of the heterostructure interface of the NiZn-YIG-NiZn tri-layer heterostructure prepared in Example 1; wherein, Figure 6In (a) is the SEM image of the hetero - bonded interface of YIG ferrite and NiZn ferrite (NZF), Figure 6 In (b) is the EDS - Mapping image of Al element, Figure 6 In (c) is the EDS - Mapping image of Bi element, Figure 6 In (d) is the EDS - Mapping image of Fe element, Figure 6 In (e) is the EDS - Mapping image of Y element, Figure 6 In (f) is the EDS - Mapping image of O element, Figure 6 In (g) is the EDS - Mapping image of Ni element, Figure 6 In (h) is the EDS - Mapping image of Zn element; Figure 7 It is the physical diagram of the sample of Example 1 and the graph of the shrinkage rate of the NiZn ferrite monomer and the YIG ferrite monomer prepared according to the preparation method of Example 1 varying with temperature. Detailed implementation manners

[0019] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] The embodiment of the present invention provides a double - ferrite triple - layer hetero - co - fired body and its preparation method. Taking the YIG - based microwave ferrite as the intermediate layer and the NiZn - based ferrite as the upper and lower layers of the stacked co - fired body. Among them, the doping amount of Bi2O3 in the NiZn ferrite material is c wt%, 0.0 < c ≤ 1.0; the chemical general formula of the YIG - based ferrite is Y 2.8-a Bi a Al 0.2 Fe5O 12 , 0.0 < a ≤ 0.5; the chemical general formula of the NiZn - based ferrite is Ni 1-b Zn b Fe2O4, 0.2 ≤ b ≤ 0.4.

[0021] Example 1 As Figure 1 shown, this embodiment provides a preparation method of a double - ferrite triple - layer hetero - co - fired body, and the specific steps are as follows: (1) Preparation of NiZn-based and YIG-based ferrite powders: Using NiO, ZnO, Fe2O3, Bi2O3, Y2O3, and Al2O3 as raw materials, respectively according to the chemical formula Ni 1-b Zn b Fe2O4 and Y 2.8-a Bi a Al 0.2 Fe5O 12 The raw materials are mixed according to the nominal chemical ratio of the metal elements to form NiZn-based ferrite mixed powder and YIG-based ferrite mixed powder. The two mixed powders are then subjected to a second wet ball milling process to obtain NiZn-based ferrite granulated powder and YIG-based ferrite granulated powder, respectively; where a = 0.5 and b = 0.40. In this embodiment, the specific method for the secondary wet ball milling treatment is as follows: The mixed powder is subjected to wet ball milling, dried and sieved, and then pre-calcined to obtain pre-calcined powder. It is then subjected to a second wet ball milling, dried and sieved, and a binder is added for granulation and uniform mixing. Finally, it is sieved to obtain granulated powder.

[0022] (2) Regulation of shrinkage characteristics of NiZn ferrite: Add 0.5wt% Bi2O3 to the granulated NiZn ferrite obtained above and mix evenly; (3) Forming of the green body of the double ferrite triple-layer heterogeneous co-fired material: The granulated powder obtained in step (2) is placed into the mold and pressed to obtain the first layer of NiZn ferrite cylindrical green body. The YIG ferrite granulated powder obtained in step (1) is added to the first layer of NiZn ferrite cylindrical green body to prepare the second layer of YIG ferrite. The granulated powder obtained in step (2) is added to the second layer of YIG ferrite and pressed to obtain the third layer of NiZn ferrite, thus obtaining the NiZn-YIG-NiZn ferrite stacked composite green body; wherein the forming pressure required for pressing is 150 MPa and the holding time is 60 s.

[0023] (4) Sintering of NiZn-YIG-NiZn ferrite stacked co-fired material: The NiZn-YIG-NiZn ferrite stacked composite green body obtained in step (3) is sintered to obtain a double ferrite triple stacked heterogeneous co-fired material. The sintering temperature is 1175℃ and the holding time is 4 h to obtain the double ferrite triple stacked heterogeneous co-fired material.

[0024] In this embodiment, the triple-layered heterogeneous co-fired body with dual ferrites uses YIG-based ferrite as the intermediate layer and NiZn-based ferrite as the upper and lower layers of the co-fired body. The general chemical formula of YIG-based ferrite is Y... 2.8-a Bi a Al 0.2 Fe5O12 a=0.5; the general chemical formula of NiZn-based ferrites is Ni 1-b Zn b Fe2O4, b = 0.4.

[0025] Example 2 The steps in this embodiment are the same as those in embodiment 1, except that the amount of Bi2O3 doped in step (2) is 1.0 wt%.

[0026] Example 3 The steps in this embodiment are the same as those in embodiment 1, except that the sintering temperature in step (4) is 1200 ℃.

[0027] Example 4 The steps in this embodiment are the same as those in embodiment 1, except that the sintering temperature in step (4) is 1150 ℃ and the holding time is 6 h.

[0028] Example 5 The steps in this embodiment are the same as in embodiment 1, except that: in step (1), the general chemical formula of NiZn-based ferrite is Ni 1-b Zn b In Fe2O4, b = 0.2.

[0029] Example 6 The steps in this embodiment are the same as those in embodiment 1, except that the molding pressure in step (3) is 200 MPa and the holding time is 30 s.

[0030] Comparative Example 1 The steps of this comparative example are the same as those of Example 1, except that the amount of Bi2O3 doped in step (2) is 0 wt% (i.e. no Bi2O3 is doped).

[0031] Comparative Example 2 The steps of this comparative example are the same as those of Example 1, except that the amount of Bi2O3 doped in step (2) is 1.5wt%.

[0032] Comparative Example 3 The steps in this comparative example are the same as those in Example 1, except that the amount of Bi2O3 doped in step (2) is 2.0 wt%.

[0033] Performance testing: Following the preparation methods of Examples 1-2 and Comparative Example 1, monomers of YIG-based ferrites and NiZn-based ferrites were prepared under the corresponding component formulations and sintering processes of Examples 1-2 and Comparative Example 1, and their performance was tested accordingly. The results are shown in Table 1.

[0034] Table 1 Comparison of Material Properties

[0035] The composite properties of the double ferrite triple-layer heterogeneous co-fired bodies prepared in Examples 1-2 and Comparative Examples 1-3 are shown in Table 2.

[0036] Table 2 Composite characteristics of trilaminated heterogeneous co-fired bodies

[0037] Note: NiZn-based and YIG-based cylindrical green blanks are prepared according to step (3) of each embodiment or comparative example, and the corresponding green blank diameter is recorded as Φ1; NiZn-based and YIG-based ferrite monomers are sintered according to the sintering process of the corresponding embodiment or comparative example, and their corresponding diameter is recorded as Φ2. Then, the shrinkage rate of NiZn-based and YIG-based ferrites is 100% × (Φ1) Φ2) / Φ1; The above Φ1 and Φ2 were measured under normal temperature and pressure conditions.

[0038] The shrinkage characteristic curve and shrinkage rate change rate of NiZn ferrite can be adjusted by incorporating a certain amount of Bi2O3 into NiZn-based ferrite. For example... Figure 2 As shown in (a), as the Bi₂O₃ doping amount increases from 0 wt% to 0.5 wt%, the shrinkage initiation temperature of NiZn ferrite decreases slightly, the shrinkage curve of the shrinkage stage becomes steeper, and it is roughly parallel to the shrinkage curve of YIG ferrite. Furthermore, the maximum shrinkage rate of NiZn ferrite shows an increasing trend, while the final shrinkage rate shows a decreasing trend. When the Bi₂O₃ doping amount increases from 0.5 wt% to 2 wt%, the shrinkage initiation temperature of NiZn ferrite continues to decrease, the steepness of the shrinkage stage of the shrinkage curve slightly decreases, and the maximum shrinkage rate shows a pattern of first increasing and then remaining basically unchanged at 1.5 wt%. The final shrinkage rate shows a roughly opposite pattern to the maximum shrinkage rate. Meanwhile, as... Figure 2 As shown in (b), the maximum shrinkage rate of NiZn ferrite significantly increased with the increase of Bi₂O₃ doping from 0 wt% to 0.5 wt%, and was extremely close to the maximum shrinkage rate of YIG. However, when the Bi₂O₃ doping increased from 0.5% to 2 wt%, the maximum shrinkage rate of NiZn ferrite showed a decreasing trend. The shrinkage rates of NiZn ferrite in Table 2 are the actual shrinkage rates of the monomer samples measured after high-temperature furnace sintering, and their trends are basically consistent with... Figure 2The final shrinkage rate of (a) has the same trend, but the shrinkage rate in the figure cannot directly reflect the actual shrinkage rate during sintering. This is because the difference in holding time, sintering temperature and atmosphere under the shrinkage curve test conditions causes the shrinkage curve to not accurately reflect the actual shrinkage rate during sintering, but it can accurately reflect the rate of change of shrinkage rate. Therefore, the shrinkage rate is based on the shrinkage rate of the sample actually sintered in the high-temperature furnace (Table 2).

[0039] Furthermore, Examples 3-6 maintained the same Bi2O3 doping amount as Example 1, and all of them exhibited good co-fired composite properties.

[0040] Figure 3 (a) and (b) confirm that the incorporation of Bi2O3 did not change the main phase of NiZn ferrite. At the same time, the main phases of YIG and NiZn ferrite remained basically unchanged after co-firing. This retention of the main phase is conducive to maintaining the excellent electromagnetic properties of the co-fired composite sample. It is expected that the co-fired composite will achieve functional complementarity of the two ferrites in the same substrate, meet the urgent need for multi-band and multi-functional integration of devices, and can be applied to the fields of filters and circulators.

[0041] Figure 4 This more intuitively demonstrates the variation law of NiZn-YIG-NiZn trilayer heterogeneous co-fired body caused by the increase of Bi2O3 doping. Figure 4 (a) to (e) show the macroscopic bonding of the heterostructured co-fired bodies with Bi₂O₃ doping amounts ranging from 0 wt% to 2 wt%. Without Bi₂O₃, the heterostructure bonding is noticeably loose, with significant cracking. However, with the addition of 0.5 wt% Bi₂O₃, the heterostructure bonding is tight without cracking or warping. With the addition of 1 wt% Bi₂O₃, although the heterostructure bonding is tight, small cracks exist on the YIG side, and slight warping occurs on the NiZn ferrite side. This is related to the micro-stress caused by the slight mismatch in the shrinkage characteristics of the co-fired matrix. When 1.5 wt% Bi₂O₃ was added, significant cracking and extremely large cracks appeared at the interface of the NiZn-YIG-NiZn trilaminated heterogeneous co-fired body, with extremely pronounced warping on the NiZn ferrite side. However, when the Bi₂O₃ content reached 2 wt%, the NiZn ferrite on one side of the NiZn-YIG-NiZn trilaminated heterogeneous co-fired body directly detached from the heterogeneous co-fired body, exhibiting significant warping. This analysis indicates that increasing the Bi₂O₃ content from 0 wt% to 1 wt% significantly improved the shrinkage characteristics of NiZn-based ferrites, making them essentially match the shrinkage characteristics of YIG. This is the fundamental reason for achieving tight bonding and minimal or even no warping and cracking in the NiZn-based ferrite and YIG trilaminated co-fired body.

[0042] Figure 5(a) to (b) show the macroscopic cross-section of the sample from Example 1 and the heterogeneous interface at the microscopic interface, which further confirms that NiZn ferrite and YIG ferrite are tightly bonded and free from cracking and warping. Figure 6 (a) to (h) present the elemental distribution diagram of Example 1. The diagram shows that the upper and lower layers mainly contain Fe, Ni, Zn, and O elements, with trace amounts of Bi element, while the middle layer mainly contains Y, Bi, Al, Fe, and O elements. At the same time, the elements are basically clearly demarcated at the bonding interface. This not only confirms that the upper and lower layers are NiZn ferrite materials and the middle layer is YIG material, but also confirms that the interdiffusion of elements at the bonding interface is extremely low. This high-quality heterogeneous bonding interface is conducive to maintaining the excellent electromagnetic properties of the heterogeneous co-fired body. Figure 7 The paper presents a physical image of the sample from Example 1, as well as a graph showing the shrinkage rate of NiZn ferrite monomers and YIG ferrite monomers prepared according to the preparation method of Example 1 as a function of temperature.

[0043] Comparative examples and comparative examples show that adding an appropriate amount (0.5 wt%) of Bi₂O₃ to the upper and lower NiZn ferrite layers significantly improves the shrinkage characteristic curve of the NiZn ferrite, with the shrinkage rate changing from 7.5 × 10⁻⁶. -4 K -1 Horizontal increase to 15×10 -4 K -1 The densification temperature was advanced and highly matched with YIG ferrite, achieving heterogeneous co-firing bonding with YIG ferrite. However, excessive Bi₂O₃ doping exacerbated the mismatch between the shrinkage rates of the two heterogeneous ferrites, worsening the warping and cracking phenomenon of the co-fired body. This further proves that Bi₂O₃... 3+ The regulatory effect of Bi₂O₃ is the main factor in achieving co-fired composite; the NiZn-YIG-NiZn tri-layer heterostructure co-fired body with appropriate amount (0.5wt%) Bi₂O₃ doping has a tight interface without warping or cracking, clear structural boundaries, and basically clear elemental distribution at the interface with extremely low interdiffusion. Furthermore, the trace doping of Bi₂O₃ in NiZn ferrite, while ensuring that the main phase of NiZn ferrite remains unchanged, also increases the saturation magnetization of NiZn ferrite. M s ), while coercivity ( H c ) and remanence ( M r The temperature was reduced, but the excellent electromagnetic properties of the co-fired material were maintained. It was the appropriate amount of Bi2O3 based on liquid-phase sintering that led to the increase in the yield rate of NiZn special oxide and the earlier densification temperature. The changes in these two factors improved its co-firing matching characteristics with YIG, and finally achieved the co-firing composite of NiZn-YIG-NiZn trilayer heterogeneous co-fired material.

[0044] The above embodiments are merely examples. The three-layer co-fired body of the present invention is not limited to a circle in planar geometry. It can also be co-pressed into square, rectangular, ring, polygonal or other customized shapes based on the design requirements of specific devices. As long as the three-layer structure is satisfied and an integral green body can be formed through lamination process, co-firing can be achieved.

[0045] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A double ferrite triple-layer heterogeneous co-fired material, characterized in that, It includes an intermediate ferrite layer and upper and lower ferrite layers. The intermediate ferrite layer is a YIG-based microwave ferrite, and the upper and lower ferrite layers are both NiZn-based ferrites doped with Bi2O3. The intermediate ferrite layer and the upper and lower ferrite layers are composited by co-firing.

2. The double ferrite triple-layer heterogeneous co-fired material as described in claim 1, characterized in that, The Bi₂O₃ doping content in the NiZn ferrite material is c wt%, 0.0 <c ≤ 1.0。 3. The double ferrite triple-layer heterogeneous co-fired material as described in any one of claims 1-2, characterized in that, The YIG-based microwave ferrite is Y 2.8-a Bi a Al 0.2 Fe5O 12 , 0.0 1- b Zn b Fe2O4, 0.2 ≤ b ≤ 0.4.​ 4. The method for preparing the double ferrite triple-layer heterogeneous co-fired material according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Using NiO powder, ZnO powder, Fe2O3 powder, Bi2O3 powder, Y2O3 powder, and Al2O3 powder as raw materials, respectively according to the chemical formula Ni 1-b Zn b Fe2O4 and Y 2.8-a Bi a Al 0.2 Fe5O 12 The raw materials were mixed according to the nominal stoichiometric ratio of the metal elements to form NiZn-based ferrite mixed powder and YIG-based ferrite mixed powder. The two mixed powders were then subjected to a second wet ball milling process to obtain NiZn-based ferrite granulated powder and YIG-based ferrite granulated powder, respectively; wherein, 0.0 <a ≤ 0.5,0.20 ≤ b ≤ 0.40; (2) Add the NiZn-based ferrite granulated powder obtained in step (1) to a set amount of Bi2O3 and mix evenly; (3) The granulated powder obtained in step (2) is placed into a mold and pressed to obtain a first layer of NiZn ferrite cylindrical green body. The YIG ferrite granulated powder obtained in step (1) is added to the first layer of NiZn ferrite cylindrical green body to prepare a second layer of YIG ferrite. The granulated powder obtained in step (2) is added to the second layer of YIG ferrite and pressed to obtain a third layer of NiZn ferrite, thus obtaining a NiZn-YIG-NiZn ferrite laminated composite green body. (4) The NiZn-YIG-NiZn ferrite stacked composite green body obtained in step (3) is sintered to obtain a double ferrite triple stacked heterogeneous co-fired material.

5. The method for preparing the double ferrite triple-layer heterogeneous co-fired body as described in claim 4, characterized in that, In step (3), the pressure during pressing is 150~200 MPa, and the holding time is 30~60 s.

6. The method for preparing the double ferrite triple-layer heterogeneous co-fired body as described in claim 4, characterized in that, In step (4), the sintering temperature is 1150 ~ 1200 ℃, and the holding time is 4 ~ 6 h.

7. The application of the double ferrite triple-layer heterogeneous co-fired material according to any one of claims 1-3 in filters and circulators.

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