A dual-phase composite ferrite material, its preparation method and application

Abstract

This invention relates to a two-phase composite ferrite material, its preparation method, and its applications. The raw materials for preparing the two-phase composite ferrite material include SrM ferrite, LiZn ferrite, and dopants. This invention combines SrM ferrite and LiZn ferrite. LiZn ferrite has advantages such as high remanence ratio, low linewidth, and high Curie temperature. Combined with the incorporation of other elements, the microstructure and magnetic properties of the two-phase composite ferrite are improved, resulting in a composite ferrite with advantages such as high remanence ratio, low linewidth, and high saturation magnetization.

Description

Technical Field

[0001] This invention relates to the field of ferrite material preparation technology, specifically to a two-phase composite ferrite material, its preparation method, and its application. Background Technology

[0002] With the continuous improvement of 5G high-frequency technology applications such as indoor hotspot coverage and urban microcells, microwave devices such as circulators and isolators are also constantly developing towards miniaturization, lightweighting, and integration. Microwave devices designed based on the gyromagnetic properties of ferrites play a crucial role in information sharing and inter-level isolation, becoming key to determining the reliability and stability of electronic communication systems. Ferrite gyromagnetic materials used in microwave devices are mainly divided into three types: spinel, garnet, and magnetoplumb. Garnet and spinel ferrites possess suitable saturation magnetization and low-loss characteristics, and are widely used in circulator and isolator designs. To achieve the spin function of the device, an external magnet is usually required to provide a bias magnetic field, but this increases the weight and size of the microwave device, hindering the miniaturization, lightweighting, and integration of the entire system.

[0003] Self-biased ferrites are ferrites that can achieve directional transmission of microwave signals through their own magnetic properties without the need for an external bias magnetic field. They possess characteristics such as high coercivity, high anisotropy, and high remanence, providing a self-biased field for microwave devices and completely eliminating the need for external magnets to achieve self-biasing. Current research on self-biased ferrites mainly focuses on improving their performance and optimizing fabrication processes to meet the development demands of high-frequency, miniaturized, and low-loss microwave devices.

[0004] CN115477534A discloses a two-phase composite ferrite material for Ku-band self-biased devices and its preparation method. The two-phase composite ferrite material includes SrM ferrite, NiCuZn ferrite, and a dopant. This invention discloses a method of first pre-calcining SrM ferrite, then mixing and grinding the pre-calcined SrM material with NiCuZn ferrite powder for further pre-calcination. The resulting two-phase composite ferrite material possesses suitable anisotropic fields, high coercivity and remanence, and low ferromagnetic resonance linewidth. However, NiCuZn ferrite exhibits high 4πM... s However, it also has disadvantages such as low remanence and high sintering temperature, and its compatibility with SrM ferrite is not high.

[0005] CN115579203A discloses a two-phase composite ferrite material for X-band self-biasing devices and its preparation method. The two-phase composite ferrite material includes SrM ferrite, YIG ferrite, and a dopant. The method involves pre-firing the SrM ferrite, then mixing and grinding the pre-fired SrM material with high-dielectric YIG powder for further pre-firing to achieve high-molecular-weight magnetic phase. r / M s and H cBy "grafting" these characteristics onto a high-dielectric, low-loss soft magnetic phase, two-phase composite ferrite materials possess suitable saturation magnetization, suitable anisotropic field, high coercivity, high remanence ratio, low ferromagnetic resonance linewidth, and high dielectric constant. However, while high-dielectric YIG ferrites possess a high dielectric constant, their Curie temperature is relatively low, which limits the operating temperature of the devices. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a two-phase composite ferrite material, its preparation method and application, which improves the microstructure and magnetic properties of the two-phase composite ferrite, so that the two-phase composite ferrite material has the advantages of high remanence ratio, low linewidth and high saturation magnetization.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a two-phase composite ferrite material, wherein the raw materials for preparing the two-phase composite ferrite material include SrM ferrite, LiZn ferrite and dopants.

[0009] The SrM ferrite is: Sr 1-x-y Ca x La y Fe 12-z Co z O 19 , where 0.3≤x≤0.4, 0.45≤y≤0.55, and 0.3≤z≤0.4.

[0010] The value 0.3 ≤ x ≤ 0.4 can be, for example, 0.3, 0.32, 0.35, 0.38 or 0.4, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] The value 0.45≤y≤0.55 can be, for example, 0.45, 0.455, 0.5, 0.52, or 0.55, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] The value 0.3≤z≤0.4 can be, for example, 0.3, 0.32, 0.35, 0.38 or 0.4, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] The LiZn ferrite is: Li 0.5-0.5a+0.5b Zn a Fe 2.4-0.5a-1.5b Ti b Bi 0.05 Mn 0.05 O4, where 0.05≤a≤0.15, 0.05≤b≤0.1.

[0014] The value 0.05≤a≤0.15 can be, for example, 0.05, 0.08, 0.1, 0.12 or 0.15, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] The value 0.05≤b≤0.1 can be, for example, 0.05, 0.06, 0.08, 0.09 or 0.1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] The two-phase composite ferrite material provided by this invention combines SrM ferrite and LiZn ferrite. LiZn ferrite has the advantages of high remanence ratio, low linewidth and high Curie temperature. With the addition of other elements, the microstructure and magnetic properties of the two-phase composite ferrite are improved, so that the composite ferrite has the advantages of high remanence ratio, low linewidth and high saturation magnetization.

[0017] Preferably, the mass ratio of LiZn ferrite to SrM ferrite is 1:(1-2.5), for example, it can be 1:1, 1:1.5, 1:2, 1:2.2 or 1:2.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Preferably, the composition of the dopant, based on the total mass percentage of SrM ferrite and LiZn ferrite, includes: Bi2O3 1.5-2wt%, H3BO3 1.5-2wt%, V2O5 1.5-2wt%, CaO 1.5-2wt%, and Nb2O5 0.05-0.1wt%.

[0019] The Bi2O3 in the dopant accounts for 1.5-2 wt% of the total mass percentage of SrM ferrite and LiZn ferrite. For example, it can be 1.5 wt%, 1.6 wt%, 1.8 wt%, 1.9 wt%, or 2 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] The H3BO3 content in the dopant accounts for 1.5-2 wt% of the total mass percentage of SrM ferrite and LiZn ferrite, for example, it can be 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.9 wt% or 2 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] The V2O5 content in the dopant accounts for 1.5-2 wt% of the total mass percentage of SrM ferrite and LiZn ferrite, for example, it can be 1.5 wt%, 1.6 wt%, 1.8 wt%, 1.9 wt% or 2 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] The CaO content in the dopant is 1.5-2 wt% of the total mass percentage of SrM ferrite and LiZn ferrite, for example, it can be 1.5 wt%, 1.6 wt%, 1.8 wt%, 1.9 wt% or 2 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] The Nb2O5 content in the dopant is 0.05-0.1 wt% of the total mass percentage of SrM ferrite and LiZn ferrite, for example, it can be 0.05 wt%, 0.06 wt%, 0.08 wt%, 0.09 wt% or 0.1 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Secondly, the present invention provides a method for preparing a dual-phase composite ferrite material as described in the first aspect, the method comprising the following steps:

[0025] (1) SrM ferrite and LiZn ferrite were mixed by first wet milling, and the resulting slurry was successively dried and pre-calcined to obtain an intermediate.

[0026] (2) The dopant in the formulation is mixed with the intermediate obtained in step (1) by a second wet milling. The resulting slurry is dehydrated and then subjected to magnetic field orientation and sintering to obtain the dual-phase composite ferrite material.

[0027] The preparation method of the two-phase composite ferrite material provided by the present invention effectively controls the grain boundary characteristics, improves the orientation degree, and increases the saturation magnetization intensity by using high-energy ball milling technology, magnetic field orientation forming technology and heat treatment technology. With the addition of other elements, the microstructure and magnetic properties of the two-phase composite ferrite are improved, making it suitable for industrial-scale production.

[0028] Preferably, the SrM ferrite in step (1) is obtained by sequentially wet ball milling, drying, sieving and calcining the raw materials prepared in the specified amount.

[0029] Preferably, the raw materials for preparation include SrCO3, CaCO3, La2O3, Co2O3, and Fe2O3.

[0030] Preferably, the mass ratio of the raw materials, deionized water and zirconia balls in the wet ball milling is 1:(0.9-1.1):(4.5-5.5), for example, it can be 1:0.9:4.5, 1:1:5 or 1:1.1:5.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the wet ball milling is performed at a speed of 60-80 r / min for 12-18 h.

[0032] The rotational speed of the wet ball mill is 60-80 r / min, for example, it can be 60 r / min, 65 r / min, 70 r / min, 75 r / min or 80 r / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] The wet ball milling time is 12-18 hours, for example, it can be 12 hours, 14 hours, 16 hours or 18 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, a dispersant is added during the wet ball milling process, and the volume ratio of the dispersant to deionized water is 1:(35-45), for example, it can be 1:35, 1:38, 1:40, 1:42 or 1:45, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] Preferably, the dispersant comprises any one or a combination of at least two of ammonia, sodium hexametaphosphate, or sodium tripolyphosphate. Typical but non-limiting combinations include a combination of ammonia and sodium hexametaphosphate, a combination of sodium hexametaphosphate and sodium tripolyphosphate, or a combination of ammonia, sodium hexametaphosphate, and sodium tripolyphosphate.

[0036] Preferably, the drying temperature is 110-130℃, for example, it can be 110℃, 115℃, 120℃, 125℃ or 130℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0037] Preferably, the sieve mesh size is 80 mesh.

[0038] Preferably, the roasting temperature is 1200-1250℃ and the time is 2-6 hours.

[0039] The roasting temperature is 1200-1250℃, for example, it can be 1200℃, 1210℃, 1220℃, 1230℃ or 1250℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0040] The roasting time is 2-6 hours, for example, it can be 2 hours, 3 hours, 4 hours, 5 hours or 6 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0041] Preferably, the raw materials for preparing the LiZn ferrite in step (1) include Li2CO3, ZnO, Fe2O3, TiO2, Bi2O3 and Mn3O4.

[0042] Preferably, in step (1), the mass ratio of powder, deionized water and zirconia balls in the first wet milling mixture is 1:(0.9-1.1):(4.5-5.5), for example, it can be 1:0.9:4.5, 1:1:5 or 1:1.1:5.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] Preferably, in step (1), the rotation speed of the first wet grinding mixture is 60-80 r / min, and the time is 12-18 h.

[0044] Step (1) The rotation speed of the first wet grinding is 60-80 r / min, for example, it can be 60 r / min, 65 r / min, 70 r / min, 75 r / min or 80 r / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] Step (1) The first wet grinding mixing time is 12-18h, for example, it can be 12h, 14h, 16h or 18h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] Preferably, in step (1), a dispersant is added to the first wet milling mixture, and the volume ratio of the dispersant to deionized water is 1:(35-45), for example, it can be 1:35, 1:38, 1:40, 1:42 or 1:45, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable. Preferably, the dispersant includes any one or a combination of at least two of ammonia, sodium hexametaphosphate or sodium tripolyphosphate. Typical but non-limiting combinations include a combination of ammonia and sodium hexametaphosphate, a combination of sodium hexametaphosphate and sodium tripolyphosphate, or a combination of ammonia, sodium hexametaphosphate and sodium tripolyphosphate.

[0047] Preferably, the drying temperature in step (1) is 110-130°C, for example, it can be 110°C, 115°C, 120°C, 125°C or 130°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0048] Preferably, step (1) includes a step of passing the material through an 80-mesh sieve after drying and before pre-firing.

[0049] Preferably, the pre-firing temperature in step (1) is 900-950℃ and the time is 2-6h.

[0050] The preheating temperature in step (1) is 900-950℃, for example, it can be 900℃, 910℃, 920℃, 930℃ or 950℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0051] The preheating time in step (1) is 2-6 hours, for example, it can be 2 hours, 3 hours, 4 hours, 5 hours or 6 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0052] Preferably, in step (2), the mass ratio of powder, deionized water and zirconia balls in the second wet milling mixture is 1:(0.9-1.1):(4.5-5.5), for example, it can be 1:0.9:4.5, 1:1:5 or 1:1.1:5.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0053] Preferably, in step (2), the rotation speed of the second wet milling mixture is 60-80 r / min, and the time is 12-18 h.

[0054] In step (2), the rotation speed of the second wet grinding is 60-80 r / min, for example, it can be 60 r / min, 65 r / min, 70 r / min, 75 r / min or 80 r / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0055] Step (2) The second wet milling mixing time is 12-18h, for example, it can be 12h, 14h, 16h or 18h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0056] Preferably, the water content of the slurry after dehydration in step (2) is 20-30%, for example, it can be 20%, 22%, 25%, 28% or 30%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0057] Preferably, the magnetic field for magnetic orientation forming in step (2) is ≥1.4T and the pressure is 2.8-3.2MPa.

[0058] The magnetic field for magnetic orientation shaping in step (2) is ≥1.4T, for example, it can be 1.4T, 1.5T, 1.6T, 1.7T or 1.8T, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0059] The magnetic field orientation forming pressure in step (2) is 2.8-3.2 MPa, for example, it can be 2.8 MPa, 2.9 MPa, 3 MPa, 3.1 MPa or 3.2 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0060] Preferably, the sintering temperature in step (2) is 1150-1250℃ and the time is 4-8h.

[0061] The sintering temperature in step (2) is 1150-1250℃, for example, it can be 1150℃, 1180℃, 1200℃, 1220℃ or 1250℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0062] The sintering time in step (2) is 4-8 hours, for example, it can be 4 hours, 5 hours, 6 hours, 7 hours or 8 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0063] Thirdly, the present invention provides an application of the dual-phase composite ferrite material as described in the first aspect, wherein the dual-phase composite ferrite material is used in a self-biased circulator.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] (1) The dual-phase composite ferrite material provided by the present invention combines SrM ferrite and LiZn ferrite. LiZn ferrite has the advantages of high remanence ratio, low linewidth and high Curie temperature. With the addition of other elements, the microstructure and magnetic properties of the dual-phase composite ferrite are improved, so that the composite ferrite has the advantages of high remanence ratio and low linewidth.

[0066] (2) The preparation method of the dual-phase composite ferrite material provided by the present invention effectively controls the grain boundary characteristics, improves the orientation degree, and increases the saturation magnetization intensity through high-energy ball milling technology, magnetic field orientation forming technology and heat treatment technology, which is suitable for industrial-scale production. Detailed Implementation

[0067] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0068] Example 1

[0069] This embodiment provides a dual-phase composite ferrite material, the raw materials for preparing the dual-phase composite ferrite material including SrM ferrite, LiZn ferrite, and a dopant; wherein the SrM ferrite is Sr 0.15 Ca0.35 La 0.5 Fe 11.7 Co 0.3 O 19 The LiZn ferrite is Li 0.475 Zn 0.1 Fe 2.275 Ti 0.05 Bi 0.05 Mn 0.05 O4, wherein the mass ratio of LiZn ferrite to SrM ferrite is 1:1.5; and the composition of the dopant, based on the total mass percentage of SrM ferrite and LiZn ferrite, includes: Bi2O3 2wt%, H3BO3 1.5wt%, V2O5 1.5wt%, CaO 2wt%, and Nb2O5 0.07wt%.

[0070] The preparation method of the dual-phase composite ferrite material includes the following steps:

[0071] (1) The raw materials were prepared by wet ball milling at 70 r / min for 14 h. The mass ratio of the raw materials, deionized water and zirconia balls in the wet ball milling was 1:1:5. Ammonia water was added in the wet ball milling, and the volume ratio of ammonia water to deionized water was 1:40. Then, the raw materials were dried at 120℃, passed through an 80-mesh sieve and calcined at 1220℃ for 4 h to obtain SrM ferrite. The raw materials included SrCO3, CaCO3, La2O3, Co2O3 and Fe2O3.

[0072] SrM ferrite and LiZn ferrite were wet-milled at 70 r / min for 14 h. The mass ratio of powder, deionized water and zirconia balls in the first wet milling was 1:1:5. Ammonia water was added in the first wet milling, and the volume ratio of ammonia water to deionized water was 1:40. The resulting slurry was dried at 120℃, passed through an 80-mesh sieve and pre-calcined at 920℃ for 4 h to obtain an intermediate. The raw materials for preparing the LiZn ferrite included Li2CO3, ZnO, Fe2O3, TiO2, Bi2O3 and Mn3O4.

[0073] (2) The dopant in the formulation and the intermediate obtained in step (1) are mixed in a second wet mill at a speed of 70 r / min for 14 h. The mass ratio of powder, deionized water and zirconia balls in the second wet mill is 1:1:5. After the slurry is dehydrated to a water content of 25%, it is magnetically oriented and shaped under a magnetic field of 1.4T and a pressure of 3MPa. After sintering at 1200℃ for 6 h, the dual-phase composite ferrite material is obtained.

[0074] Example 2

[0075] This embodiment provides a dual-phase composite ferrite material, the raw materials for preparing the dual-phase composite ferrite material including SrM ferrite, LiZn ferrite, and a dopant; wherein the SrM ferrite is Sr 0.25 Ca 0.3 La 0.45 Fe 11.65 Co 0.35 O 19 The LiZn ferrite is Li 0.51 Zn 0.05 Fe 2.27 Ti 0.07 Bi 0.05 Mn 0.05 O4, wherein the mass ratio of LiZn ferrite to SrM ferrite is 1:1; based on the total mass percentage of SrM ferrite and LiZn ferrite, the composition of the dopant includes: Bi2O3 1.5wt%, H3BO3 2wt%, V2O5 1.5wt%, CaO 1.5wt%, Nb2O5 0.05wt%.

[0076] The preparation method of the dual-phase composite ferrite material includes the following steps:

[0077] (1) The raw materials were prepared by wet ball milling at 60 r / min for 18 h. The mass ratio of the raw materials, deionized water and zirconia balls in the wet ball milling was 1:0.9:4.5. Sodium hexametaphosphate was added in the wet ball milling, and the volume ratio of sodium hexametaphosphate to deionized water was 1:35. Then, the raw materials were dried at 110℃, passed through an 80-mesh sieve and calcined at 1200℃ for 6 h to obtain SrM ferrite. The raw materials included SrCO3, CaCO3, La2O3, Co2O3 and Fe2O3.

[0078] SrM ferrite and LiZn ferrite were wet-milled for 18 hours at 60 r / min. The mass ratio of powder, deionized water and zirconia balls in the first wet milling was 1:0.9:4.5. Sodium hexametaphosphate was added in the first wet milling, and the volume ratio of sodium hexametaphosphate to deionized water was 1:35. The resulting slurry was dried at 110℃, passed through an 80-mesh sieve, and pre-calcined at 900℃ for 6 hours to obtain an intermediate. The raw materials for preparing the LiZn ferrite included Li2CO3, ZnO, Fe2O3, TiO2, Bi2O3 and Mn3O4.

[0079] (2) The dopant in the formulation and the intermediate obtained in step (1) are mixed in a second wet mill at a speed of 60 r / min for 18 h. The mass ratio of powder, deionized water and zirconia balls in the second wet mill is 1:0.9:4.5. After the slurry is dehydrated to a water content of 20%, it is magnetically oriented and shaped under a magnetic field of 1.5T and a pressure of 2.8MPa. After sintering at 1150℃ for 8 h, the dual-phase composite ferrite material is obtained.

[0080] Example 3

[0081] This embodiment provides a dual-phase composite ferrite material, the raw materials for preparing the dual-phase composite ferrite material including SrM ferrite, LiZn ferrite, and a dopant; wherein the SrM ferrite is Sr 0.05 Ca 0.4 La 0.55 Fe 11.65 Co 0.35 O 19 The LiZn ferrite is Li 0.475 Zn 0.15 Fe 2.175 Ti 0.1 Bi 0.05 Mn 0.05 O4, wherein the mass ratio of LiZn ferrite to SrM ferrite is 1:2; based on the total mass percentage of SrM ferrite and LiZn ferrite, the composition of the dopant includes: Bi2O3 1.8wt%, H3BO3 1.7wt%, V2O5 1.8wt%, CaO 2wt%, Nb2O5 0.1wt%.

[0082] The preparation method of the dual-phase composite ferrite material includes the following steps:

[0083] (1) The raw materials were prepared by wet ball milling at 80 r / min for 12 h. The mass ratio of the raw materials, deionized water and zirconia balls in the wet ball milling was 1:1.1:5.5. Sodium tripolyphosphate was added in the wet ball milling, and the volume ratio of sodium tripolyphosphate to deionized water was 1:45. Then, the raw materials were dried at 130℃, passed through an 80-mesh sieve and calcined at 1250℃ for 2 h to obtain SrM ferrite. The raw materials included SrCO3, CaCO3, La2O3, Co2O3 and Fe2O3.

[0084] SrM ferrite and LiZn ferrite were wet-milled for 12 hours at 80 r / min. The mass ratio of powder, deionized water and zirconia balls in the first wet milling was 1:1.1:5.5. Sodium tripolyphosphate was added in the first wet milling, and the volume ratio of sodium tripolyphosphate to deionized water was 1:45. The resulting slurry was dried at 130℃, passed through an 80-mesh sieve, and pre-calcined at 950℃ for 2 hours to obtain an intermediate. The raw materials for preparing the LiZn ferrite included Li2CO3, ZnO, Fe2O3, TiO2, Bi2O3 and Mn3O4.

[0085] (2) The dopant in the formulation and the intermediate obtained in step (1) are mixed in a second wet mill at a speed of 80 r / min for 12 h. The mass ratio of powder, deionized water and zirconia balls in the second wet mill is 1:1.1:5.5. After the slurry is dehydrated to a water content of 30%, it is magnetically oriented and shaped under a magnetic field of 1.6T and a pressure of 3.2MPa. After sintering at 1250℃ for 4 h, the dual-phase composite ferrite material is obtained.

[0086] Example 4

[0087] This embodiment provides a dual-phase composite ferrite material, which differs from Embodiment 1 in that the SrM ferrite is adjusted to Sr... 0.1 Ca 0.35 La 0.55 Fe 11.6 Co 0.4 O 19 The LiZn ferrite is adjusted to Li 0.5 Zn 0.1 Fe 2.2 Ti 0.1 Bi 0.05 Mn 0.05 O4, the mass ratio of LiZn ferrite to SrM ferrite is adjusted to 1:2.5, the ammonia water in step (1) is adjusted to a mixture of ammonia water and sodium tripolyphosphate at a mass ratio of 1:1, and the rest is the same as in Example 1.

[0088] Example 5

[0089] This embodiment provides a dual-phase composite ferrite material, which differs from Embodiment 1 in that the SrM ferrite is adjusted to Sr... 0.145 Ca 0.4 La 0.455 Fe 11.65 Co 0.35 O 19 The LiZn ferrite is adjusted to Li 0.475 Zn 0.15 Fe 2.175 Ti 0. 1Bi0.05 Mn 0.05 O4, the mass ratio of LiZn ferrite to SrM ferrite is adjusted to 1:2, the ammonia water in step (1) is adjusted to a mixture of ammonia water and sodium hexametaphosphate at a mass ratio of 1:1, and the rest is the same as in Example 1.

[0090] Example 6

[0091] This embodiment provides a two-phase composite ferrite material. The difference from Embodiment 1 is that the composition of the dopant is adjusted to: Bi2O3 0.8wt%, H3BO3 0.6wt%, SiO2 0.4wt%, CaCO3 1.2wt%, BaTiO3 0.7wt%. The ammonia water in step (1) is adjusted to a mixture of ammonia water, sodium hexametaphosphate and sodium tripolyphosphate in a mass ratio of 1:1:1. The rest is the same as in Embodiment 1.

[0092] Example 7

[0093] This embodiment provides a dual-phase composite ferrite material. The difference from Embodiment 1 is that the mass ratio of LiZn ferrite to SrM ferrite is adjusted to 1:0.5, and the ammonia water in step (1) is adjusted to a mixture of ammonia water, sodium hexametaphosphate and sodium tripolyphosphate in a mass ratio of 1:1:1. The rest is the same as in Embodiment 1.

[0094] Example 8

[0095] This embodiment provides a dual-phase composite ferrite material. The difference from Embodiment 1 is that the mass ratio of LiZn ferrite to SrM ferrite is adjusted to 1:3, and the ammonia water in step (1) is adjusted to a mixture of ammonia water and sodium tripolyphosphate at a mass ratio of 1:1. The rest is the same as in Embodiment 1.

[0096] Example 9

[0097] This embodiment provides a two-phase composite ferrite material. The preparation method of the two-phase composite ferrite material is different from that of Embodiment 1. Except for adjusting the pre-firing temperature in step (1) to 850°C, the rest is the same as that of Embodiment 1.

[0098] Example 10

[0099] This embodiment provides a two-phase composite ferrite material. The preparation method of the two-phase composite ferrite material is different from that of Embodiment 1. Except for adjusting the pre-firing temperature in step (1) to 1000℃, the rest is the same as that of Embodiment 1.

[0100] Comparative Example 1

[0101] This comparative example provides a two-phase composite ferrite material, which differs from Example 1 in that the SrM ferrite is adjusted to Sr... 0.15 Ca 0.25 La 0.6 Fe 11.5 Co 0.5 O 19 The LiZn ferrite is adjusted to Li 0.5 Zn 0.2 Fe2Ti 0.2 Bi 0.05 Mn 0.05 O4, the mass ratio of LiZn ferrite to SrM ferrite is adjusted to 2:1, and the rest is the same as in Example 1.

[0102] Comparative Example 2

[0103] This comparative example provides a two-phase composite ferrite material, which differs from Example 1 in that the SrM ferrite is adjusted to Sr... 0.1 Ca 0.5 La 0.4 Fe 11.5 Co 0.5 O 19 The LiZn ferrite is adjusted to Li 0.365 Zn 0.3 Fe 2.205 Ti 0.03 Bi 0.05 Mn 0.05 O4, the mass ratio of LiZn ferrite to SrM ferrite is adjusted to 2:1, and the rest is the same as in Example 1.

[0104] Samples of the two-phase composite ferrite materials provided in Examples 1-10 and Comparative Examples 1 and 2 were prepared, and the saturation magnetization was tested at 4πM. s Remanence ratio M r / M s Ferromagnetic resonance linewidth ΔH, dielectric constant ε r Coercivity H c The results are shown in Table 1.

[0105] Table 1

[0106] Example 1 4268 0.92 318 15.6 3260 Example 2 4249 0.90 314 15.4 3199 Example 3 4216 0.92 320 15.1 3252 Example 4 4254 0.91 322 15.3 3122 Example 5 4257 0.91 318 15.5 3233 Example 6 4235 0.90 323 15.5 3148 Example 7 4254 0.68 289 15.1 1445 Example 8 4249 0.93 568 15.1 3452 Example 9 3723 0.84 482 15.2 2645 Example 10 3845 0.81 531 15.1 2635 Comparative Example 1 4271 0.90 662 15.5 3324 Comparative Example 2 4231 0.91 689 15.2 3452

[0107] As can be seen from Table 1, the two-phase composite ferrite material provided by the present invention has advantages such as high saturation magnetization, high remanence ratio, low linewidth, high dielectric constant and high coercivity.

[0108] A comparison of Examples 1 and 6 shows that, compared to dopants in the prior art, the dopant provided by this invention enables the two-phase composite ferrite material to maintain a high remanence ratio and coercivity while exhibiting a low linewidth and good self-biasing characteristics. A comparison of Examples 1 and Examples 7 and 8 shows that when the proportion of LiZn ferrite is large, the linewidth and coercivity decrease, and when the LiZn content is low, the self-biasing characteristics are significantly affected. A comparison of Examples 1 and Examples 9 and 10 shows that if the pre-firing temperature is too low or too high, the linewidth will increase, the coercivity will decrease, and the self-biasing characteristics will be affected.

[0109] By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that if the content of each component in LiZn ferrite and SrM ferrite exceeds the limit, the overall magnetic performance will decrease, thereby affecting its application in self-biased circulators.

[0110] In summary, the two-phase composite ferrite material provided by this invention combines SrM ferrite and LiZn ferrite. LiZn ferrite has the advantages of high remanence ratio, low linewidth and high Curie temperature. With the addition of other elements, the microstructure and magnetic properties of the two-phase composite ferrite are improved, so that the composite ferrite has the advantages of high remanence ratio and low linewidth.

[0111] The preparation method of the two-phase composite ferrite material provided by the present invention effectively controls the grain boundary characteristics, improves the orientation degree, and increases the saturation magnetization intensity through high-energy ball milling technology, magnetic field orientation forming technology and heat treatment technology, which is suitable for industrial-scale production.

[0112] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A two-phase composite ferrite material, characterized in that, The raw materials for preparing the dual-phase composite ferrite material include SrM ferrite, LiZn ferrite, and dopants. The SrM ferrite is: Sr 1-x-y Ca x La y Fe 12-z Co z O 19 Where 0.3≤x≤0.4, 0.45≤y≤0.55, and 0.3≤z≤0.4; The LiZn ferrite is: Li 0.5-0.5a+0.5b Zn a Fe 2.4-0.5a-1.5b Ti b Bi 0.05 Mn 0.05 O4, where 0.05≤a≤0.15, 0.05≤b≤0.1; The mass ratio of LiZn ferrite to SrM ferrite is 1:(1-2.5); based on the total mass percentage of SrM ferrite and LiZn ferrite, the composition of the dopant includes: Bi2O3 1.5-2wt%, H3BO3 1.5-2wt%, V2O5 1.5-2wt%, CaO 1.5-2wt%, Nb2O5 0.05-0.1wt%; The preparation method of the dual-phase composite ferrite material includes a step of pre-firing SrM ferrite and LiZn ferrite at 900-950℃.

2. A method for preparing the dual-phase composite ferrite material as described in claim 1, characterized in that, The preparation method includes the following steps: (1) SrM ferrite and LiZn ferrite are first wet-milled and mixed. The resulting slurry is then dried and pre-calcined at 900-950℃ to obtain an intermediate. (2) The dopant in the formulation is mixed with the intermediate obtained in step (1) by a second wet milling. The resulting slurry is dehydrated and then subjected to magnetic field orientation and sintering to obtain the dual-phase composite ferrite material.

3. The preparation method according to claim 2, characterized in that, The SrM ferrite in step (1) is obtained by sequentially wet ball milling, drying, sieving and calcining the raw materials prepared in the formula amount.

4. The preparation method according to claim 3, characterized in that, The raw materials for preparation include SrCO3, CaCO3, La2O3, Co2O3, and Fe2O3.

5. The preparation method according to claim 3, characterized in that, The mass ratio of raw materials, deionized water, and zirconia balls in the wet ball milling process is 1:(0.9-1.1):(4.5-5.5).

6. The preparation method according to claim 3, characterized in that, The wet ball milling speed is 60-80 r / min, and the time is 12-18 h.

7. The preparation method according to claim 3, characterized in that, A dispersant is added during the wet ball milling process, and the volume ratio of the dispersant to deionized water is 1:(35-45).

8. The preparation method according to claim 3, characterized in that, The drying temperature is 110-130℃.

9. The preparation method according to claim 3, characterized in that, The roasting temperature is 1200-1250℃, and the time is 2-6 hours.

10. The preparation method according to claim 2, characterized in that, The raw materials for preparing the LiZn ferrite in step (1) include Li2CO3, ZnO, Fe2O3, TiO2, Bi2O3 and Mn3O4.

11. The preparation method according to claim 2, characterized in that, In step (1), the mass ratio of powder, deionized water and zirconia balls in the first wet milling mixture is 1:(0.9-1.1):(4.5-5.5).

12. The preparation method according to claim 2, characterized in that, Step (1) The rotation speed of the first wet grinding mixture is 60-80 r / min, and the time is 12-18 h.

13. The preparation method according to claim 2, characterized in that, Step (1) A dispersant is added to the first wet milling mixture, and the volume ratio of the dispersant to deionized water is 1:(35-45).

14. The preparation method according to claim 2, characterized in that, The drying temperature in step (1) is 110-130℃.

15. The preparation method according to claim 2, characterized in that, Step (1) includes a step of passing the material through an 80-mesh sieve after drying and before pre-firing.

16. The preparation method according to claim 2, characterized in that, The preheating time in step (1) is 2-6 hours.

17. The preparation method according to claim 2, characterized in that, In step (2), the mass ratio of powder, deionized water and zirconia balls in the second wet milling mixture is 1:(0.9-1.1):(4.5-5.5).

18. The preparation method according to claim 2, characterized in that, In step (2), the rotation speed of the second wet grinding mixture is 60-80 r / min, and the time is 12-18 h.

19. The preparation method according to claim 2, characterized in that, In step (2), the dewatering process is carried out until the moisture content of the slurry is 20-30%.

20. The preparation method according to claim 2, characterized in that, The magnetic field for magnetic orientation forming in step (2) is ≥1.4T and the pressure is 2.8-3.2MPa.

21. The preparation method according to claim 2, characterized in that, The sintering temperature in step (2) is 1150-1250℃ and the time is 4-8h.

22. An application of the dual-phase composite ferrite material as described in claim 1, characterized in that, The dual-phase composite ferrite material is used in a self-biased circulator.