Two-phase composite ferrite material as well as preparation method and application thereof

Abstract

The invention relates to a double-phase composite ferrite material as well as a preparation method and application thereof. The double-phase composite ferrite material is prepared from the following raw materials: SrM ferrite, LiZn ferrite and a doping agent. According to the invention, the SrM ferrite and the LiZn ferrite are combined, the LiZn ferrite has the advantages of high remanence ratio, low line width and high Curie temperature, and other elements are doped, so that the microstructure and magnetic characteristics of the double-phase composite ferrite are improved, and the composite ferrite has the advantages of high remanence ratio, low line width, high saturation magnetization and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of ferrite material preparation, and in particular to a dual-phase composite ferrite material and a preparation method and application thereof. Background Art

[0002] With the increasing application of 5G high-frequency technologies such as indoor hotspot coverage and urban microcells, microwave devices such as circulators and isolators are also developing in the direction of miniaturization, lightness, and integration. Microwave devices designed based on the gyromagnetic properties of ferrites play a vital role in information sharing and inter-stage isolation, becoming the key to the reliability and stability of electronic communication systems. Ferrite gyromagnetic materials used in microwave devices are mainly divided into three types: spinel, garnet, and magnetoplumbite. Garnet and spinel ferrites have suitable saturation magnetization strength and low loss characteristics and are widely used in circulator and isolator designs. In order to realize the spin function of the device, an external magnet is usually required to provide a bias magnetic field, but this increases the weight and volume of the microwave device, which is not conducive to the miniaturization, lightness, and integration of the entire system.

[0003] Self-bias ferrites are ferrites that, without an external bias magnetic field, can achieve directional transmission of microwave signals through their own magnetic properties. They possess properties such as high coercivity, high anisotropy, and high remanence ratio. They can provide a self-bias field for microwave devices, completely freeing them from the constraints of external magnets and achieving self-biasing properties. Research on self-bias ferrites is currently focused on improving their performance and optimizing their preparation processes to meet the development needs of microwave devices with higher frequencies, smaller sizes, and lower losses.

[0004] CN115477534A discloses a dual-phase composite ferrite material for Ku-band self-biased devices and a preparation method thereof. The dual-phase composite ferrite material comprises SrM ferrite, NiCuZn ferrite and a dopant. The invention discloses that the SrM ferrite is pre-fired first and then the SrM pre-fired material and NiCuZn ferrite raw powder are mixed and ground and pre-fired. The obtained dual-phase composite ferrite material has the characteristics of suitable anisotropy field, high coercivity and remanence ratio, and low ferromagnetic resonance line width. However, NiCuZn ferrite has high 4πM s At the same time, it has the disadvantages of relatively low remanence and high sintering temperature, and is not highly compatible with SrM ferrite.

[0005] CN115579203A discloses a dual-phase composite ferrite material for X-band self-bias devices and a preparation method thereof. The dual-phase composite ferrite material comprises SrM ferrite, YIG ferrite and a dopant. The SrM ferrite is pre-sintered first, and then the SrM pre-sintered material and high dielectric YIG raw powder are mixed and ground and pre-sintered to achieve a high-M magnetic phase. r / M s and H cBy "grafting" these properties onto a high-dielectric, low-loss soft magnetic phase, the dual-phase composite ferrite material combines suitable saturation magnetization, an appropriate anisotropy field, high coercivity, high remanence ratio, low ferromagnetic resonance linewidth, and a high dielectric constant. However, high-dielectric YIG ferrites, while possessing a high dielectric constant, also have a low Curie temperature, limiting the operating temperature of the device. Summary of the Invention

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

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

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

[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 0.3≤x≤0.4 may be, for example, 0.3, 0.32, 0.35, 0.38 or 0.4, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0011] The 0.45≤y≤0.55 may be, for example, 0.45, 0.455, 0.5, 0.52 or 0.55, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0012] The 0.3≤z≤0.4 may be, for example, 0.3, 0.32, 0.35, 0.38 or 0.4, but is not limited to the listed values, and other values ​​not listed within the numerical 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 0.05≤a≤0.15 may be, for example, 0.05, 0.08, 0.1, 0.12 or 0.15, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0015] The 0.05≤b≤0.1 may be, for example, 0.05, 0.06, 0.08, 0.09 or 0.1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] 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 line width and high Curie temperature. The addition of other elements improves the microstructure and magnetic properties of the dual-phase composite ferrite, so that the composite ferrite has the advantages of high remanence ratio, low line width and high saturation magnetization.

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

[0018] Preferably, 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%, and Nb2O5 0.05-0.1wt%.

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

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

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

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

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

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

[0025] (1) SrM ferrite and LiZn ferrite are first wet-milled and mixed, and the resulting slurry is dried and pre-calcined in sequence to obtain an intermediate;

[0026] (2) The formulated dopant and the intermediate obtained in step (1) are mixed by a second wet grinding process, and the obtained slurry is dehydrated, and then subjected to magnetic field orientation molding and sintering in sequence to obtain the dual-phase composite ferrite material.

[0027] 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 molding technology and heat treatment technology. Combined with the incorporation of other elements, the microstructure and magnetic properties of the dual-phase composite ferrite are improved, and the material is suitable for industrial-scale production.

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

[0029] Preferably, the preparation raw materials 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, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the wet ball milling has a rotation speed of 60-80 r / min and a time of 12-18 h.

[0032] The rotation 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, and other values ​​not listed within the numerical range are also applicable.

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

[0034] Preferably, a dispersant is added to the wet ball milling, 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, and other values ​​not listed within the numerical range are also applicable.

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

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

[0037] Preferably, the mesh number of the sieving is 80 meshes.

[0038] Preferably, the calcination temperature is 1200-1250° C. and the calcination time is 2-6 hours.

[0039] The calcination temperature is 1200-1250° C., for example, 1200° C., 1210° C., 1220° C., 1230° C. or 1250° C., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] The calcination time is 2-6 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours or 6 hours, but is not limited to the listed values, and other values ​​not listed within the numerical 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, the mass ratio of the powder, deionized water and zirconia balls in the first wet grinding mixing in step (1) 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, and other values ​​not listed within the numerical range are also applicable.

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

[0044] The rotation speed of the first wet grinding mixing in step (1) 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 values ​​not listed within the numerical range are also applicable.

[0045] The time for the first wet grinding and mixing in step (1) is 12-18 hours, for example, 12 hours, 14 hours, 16 hours or 18 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0046] Preferably, a dispersant is added to the first wet grinding mixing in step (1), 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 it is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable. Preferably, the dispersant includes any one or a combination of at least two of ammonia water, sodium hexametaphosphate or sodium tripolyphosphate. Typical but non-limiting combinations include a combination of ammonia water and sodium hexametaphosphate, a combination of sodium hexametaphosphate and sodium tripolyphosphate, or a combination of ammonia water, sodium hexametaphosphate and sodium tripolyphosphate.

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

[0048] Preferably, after the drying in step (1) and before the pre-calcination, the step of passing through an 80-mesh sieve is further included.

[0049] Preferably, the pre-calcination temperature in step (1) is 900-950° C. and the pre-calcination time is 2-6 hours.

[0050] The pre-calcination temperature in step (1) is 900-950°C, for example, 900°C, 910°C, 920°C, 930°C or 950°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0051] The pre-burning time in step (1) is 2-6 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours or 6 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0052] Preferably, the mass ratio of the powder, deionized water and zirconia balls in the second wet grinding mixing in step (2) 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, and other values ​​not listed within the numerical range are also applicable.

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

[0054] The rotation speed of the second wet grinding mixing in step (2) 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 values ​​not listed within the numerical range are also applicable.

[0055] The time for the second wet grinding and mixing in step (2) is 12-18 hours, for example, 12 hours, 14 hours, 16 hours or 18 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

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

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

[0058] The magnetic field for the magnetic field orientation molding 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 values ​​not listed within the numerical range are also applicable.

[0059] The pressure of the magnetic field orientation molding 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 values ​​not listed within the numerical range are also applicable.

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

[0061] The sintering temperature in step (2) is 1150-1250°C, for example, 1150°C, 1180°C, 1200°C, 1220°C or 1250°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

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

[0063] In a third aspect, 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 with LiZn ferrite. LiZn ferrite has the advantages of high remanence ratio, low line width and high Curie temperature. Combined with the incorporation 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, low line width, etc.

[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 molding technology and heat treatment technology, and is suitable for industrial-scale production. DETAILED DESCRIPTION

[0067] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0068] Example 1

[0069] This embodiment provides a dual-phase composite ferrite material, the raw materials for preparing the dual-phase composite ferrite material include SrM ferrite, LiZn ferrite and dopant; 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, the mass ratio of the LiZn ferrite to the SrM ferrite is 1:1.5; based on the total mass percentage of the SrM ferrite and the LiZn ferrite, the composition of the dopant includes: Bi2O32wt%, H3BO3 1.5wt%, V2O5 1.5wt%, CaO2wt%, and Nb2O5 0.07wt%.

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

[0071] (1) The raw materials prepared in the formula amount are wet-milled at a rotation speed of 70 r / min for 14 hours, wherein the mass ratio of the raw materials, deionized water and zirconia balls in the wet ball milling is 1:1:5, and ammonia water is added during the wet ball milling, wherein the volume ratio of ammonia water to deionized water is 1:40; then, the ferrite is dried at 120°C, passed through an 80-mesh sieve and calcined at 1220°C for 4 hours to obtain SrM ferrite; the raw materials prepared include SrCO3, CaCO3, La2O3, Co2O3 and Fe2O3.

[0072] The SrM ferrite and LiZn ferrite are first wet-milled and mixed at a speed of 70 r / min for 14 hours. The mass ratio of powder, deionized water and zirconia balls in the first wet-milling mixture is 1:1:5. Ammonia water is added to the first wet-milling mixture, and the volume ratio of ammonia water to deionized water is 1:40. The obtained slurry is dried at 120°C, passed through an 80-mesh sieve and pre-calcined at 920°C for 4 hours to obtain an intermediate. The raw materials for preparing the LiZn ferrite include Li2CO3, ZnO, Fe2O3, TiO2, Bi2O3 and Mn3O4.

[0073] (2) The formulated dopant and the intermediate obtained in step (1) are mixed by a second wet grinding at a rotation speed of 70 r / min for 14 hours, wherein the mass ratio of the powder, deionized water and zirconia balls in the second wet grinding is 1:1:5; the obtained slurry is dehydrated to a water content of 25%, and then subjected to magnetic field orientation molding under a magnetic field of 1.4 T and a pressure of 3 MPa, and sintered at 1200° C. for 6 hours to obtain the dual-phase composite ferrite material.

[0074] Example 2

[0075] This embodiment provides a dual-phase composite ferrite material, the raw materials for preparing the dual-phase composite ferrite material include SrM ferrite, LiZn ferrite and dopant; 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, the mass ratio of the LiZn ferrite to the SrM ferrite is 1:1; based on the total mass percentage of the SrM ferrite and the LiZn ferrite, the composition of the dopant includes: Bi2O31.5wt%, H3BO3 2wt%, V2O5 1.5wt%, CaO1.5wt%, and Nb2O5 0.05wt%.

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

[0077] (1) The raw materials prepared in the formula amount are wet-milled at a rotation speed of 60 r / min for 18 hours, wherein the mass ratio of the raw materials, deionized water and zirconia balls in the wet ball milling is 1:0.9:4.5, and sodium hexametaphosphate is added in the wet ball milling, wherein the volume ratio of sodium hexametaphosphate to deionized water is 1:35; then, SrM ferrite is obtained after being dried at 110°C, passed through an 80-mesh sieve and calcined at 1200°C for 6 hours; the raw materials prepared include SrCO3, CaCO3, La2O3, Co2O3 and Fe2O3.

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

[0079] (2) The formulated dopant and the intermediate obtained in step (1) are mixed by a second wet grinding at a rotation speed of 60 r / min for 18 hours, wherein the mass ratio of the powder, deionized water and zirconia balls in the second wet grinding is 1:0.9:4.5; the obtained slurry is dehydrated to a water content of 20%, and then subjected to magnetic field orientation molding under a magnetic field of 1.5 T and a pressure of 2.8 MPa, and sintered at 1150° C. for 8 hours to obtain the dual-phase composite ferrite material.

[0080] Example 3

[0081] This embodiment provides a dual-phase composite ferrite material, the raw materials for preparing the dual-phase composite ferrite material include SrM ferrite, LiZn ferrite and dopant; 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, the mass ratio of the LiZn ferrite to the SrM ferrite is 1:2; based on the total mass percentage of the SrM ferrite and the LiZn ferrite, the composition of the dopant includes: Bi2O31.8wt%, H3BO3 1.7wt%, V2O5 1.8wt%, CaO2wt%, and Nb2O5 0.1wt%.

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

[0083] (1) The raw materials prepared in the formula amount are wet-milled at a rotation speed of 80 r / min for 12 hours, wherein the mass ratio of the raw materials, deionized water and zirconium oxide balls in the wet ball milling is 1:1.1:5.5, and sodium tripolyphosphate is added in the wet ball milling, wherein the volume ratio of sodium tripolyphosphate to deionized water is 1:45; then, the ferrite is dried at 130°C, passed through an 80-mesh sieve and calcined at 1250°C for 2 hours to obtain SrM ferrite; the raw materials prepared include SrCO3, CaCO3, La2O3, Co2O3 and Fe2O3.

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

[0085] (2) The formulated dopant and the intermediate obtained in step (1) are mixed by a second wet grinding process at a rotation speed of 80 r / min for 12 h, wherein the mass ratio of the powder, deionized water and zirconia balls in the second wet grinding process is 1:1.1:5.5; the obtained slurry is dehydrated to a water content of 30%, and then subjected to magnetic field orientation molding under a magnetic field of 1.6 T and a pressure of 3.2 MPa, and sintered at 1250° C. for 4 h to obtain the dual-phase composite ferrite material.

[0086] Example 4

[0087] This embodiment provides a dual-phase composite ferrite material. The difference from embodiment 1 is 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 the LiZn ferrite to the 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 in a mass ratio of 1:1, and the rest are the same as Example 1.

[0088] Example 5

[0089] This embodiment provides a dual-phase composite ferrite material. The difference from embodiment 1 is 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 the LiZn ferrite to the SrM ferrite is adjusted to 1:2, the ammonia water in step (1) is adjusted to a mixture of ammonia water and sodium hexametaphosphate in a mass ratio of 1:1, and the rest are the same as Example 1.

[0090] Example 6

[0091] This embodiment provides a dual-phase composite ferrite material, which differs from Example 1 in that the composition of the dopant is adjusted to: Bi2O3 0.8wt%, H3BO3 0.6wt%, SiO2 0.4wt%, CaCO3 1.2wt%, BaTiO3 0.7wt%, 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 Example 1.

[0092] Example 7

[0093] This embodiment provides a dual-phase composite ferrite material, which differs from Example 1 in that the mass ratio of the LiZn ferrite to the 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 Example 1.

[0094] Example 8

[0095] This embodiment provides a dual-phase composite ferrite material, which differs from Example 1 in that the mass ratio of the LiZn ferrite to the 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 in a mass ratio of 1:1. The rest is the same as Example 1.

[0096] Example 9

[0097] This embodiment provides a dual-phase composite ferrite material. The difference between the preparation method of the dual-phase composite ferrite material and that of Example 1 is that, except for adjusting the pre-firing temperature in step (1) to 850° C., the rest is the same as that of Example 1.

[0098] Example 10

[0099] This embodiment provides a dual-phase composite ferrite material. The difference between the preparation method of the dual-phase composite ferrite material and that of Example 1 is that, except for adjusting the pre-firing temperature in step (1) to 1000° C., the rest is the same as that of Example 1.

[0100] Comparative Example 1

[0101] This comparative example provides a dual-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 the LiZn ferrite to the SrM ferrite is adjusted to 2:1, and the rest are the same as in Example 1.

[0102] Comparative Example 2

[0103] This comparative example provides a dual-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 the LiZn ferrite to the SrM ferrite is adjusted to 2:1, and the rest are the same as in Example 1.

[0104] The dual-phase composite ferrite materials provided in Examples 1-10 and Comparative Examples 1 and 2 were sampled and tested for saturation magnetization 4πM. s , remanence ratio M r / M s , ferromagnetic resonance linewidth △H, dielectric constant ε r , coercive force H c The results are shown in Table 1.

[0105] Table 1

[0106] <![CDATA[4πM s (Gs)]]> <![CDATA[M r / M s ]]> △H(Oe) <![CDATA[ε r ]]> <![CDATA[H c (You)]]> 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] It can be seen from Table 1 that the dual-phase composite ferrite material provided by the present invention has the advantages of higher saturation magnetization, high remanence ratio, low line width, high dielectric constant and high coercive force.

[0108] By comparing Example 1 with Example 6, it can be seen that compared with the dopants in the prior art, the dopants provided by the present invention can enable the dual-phase composite ferrite material to have a lower line width while maintaining a high remanence ratio and coercive force, and have better self-bias characteristics; by comparing Example 1 with Examples 7 and 8, it can be seen that when the proportion of LiZn ferrite is large, the line width and coercive force are reduced, and when the LiZn content is low, the self-bias characteristics will be significantly affected; by comparing Example 1 with Examples 9 and 10, it can be seen that if the pre-firing temperature is too low or too high, the line width will increase, the coercive force will become lower, and the self-bias characteristics will be affected.

[0109] By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that when the content of each component in LiZn ferrite and SrM ferrite exceeds the specified range, the overall magnetic properties will be reduced, thereby affecting their application in self-biased circulators.

[0110] In summary, the dual-phase composite ferrite material provided by the present invention combines SrM ferrite with LiZn ferrite. LiZn ferrite has the advantages of high remanence ratio, low line width and high Curie temperature. Combined with the incorporation 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, low line width and the like.

[0111] 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 molding technology and heat treatment technology, and is suitable for industrial-scale production.

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

Claims

1. A dual-phase composite ferrite material, characterized in that: The raw materials for preparing the dual-phase composite ferrite material include SrM ferrite, LiZn ferrite and dopant; 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, 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.

2. The dual-phase composite ferrite material according to claim 1, characterized in that: The mass ratio of the LiZn ferrite to the SrM ferrite is 1:(1-2.5).

3. The dual-phase composite ferrite material according to claim 1 or 2, characterized in that: Calculated based on the total mass percentage of SrM ferrite and LiZn ferrite, the dopant composition includes: Bi2O3 1.5-2wt%, H3BO3 1.5-2wt%, V2O5 1.5-2wt%, CaO 1.5-2wt%, and Nb2O5 0.05-0.1wt%.

4. A method for preparing the dual-phase composite ferrite material according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) SrM ferrite and LiZn ferrite are first wet-milled and mixed, and the resulting slurry is dried and pre-calcined in sequence to obtain an intermediate; (2) The formulated dopant and the intermediate obtained in step (1) are mixed by a second wet grinding process, and the obtained slurry is dehydrated, and then subjected to magnetic field orientation molding and sintering in sequence to obtain the dual-phase composite ferrite material.

5. The preparation method according to claim 4, characterized in that The SrM ferrite in step (1) is obtained by wet ball milling, drying, sieving and calcining raw materials in a prescribed amount; Preferably, the preparation raw materials include SrCO3, CaCO3, La2O3, Co2O3 and Fe2O3; 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); Preferably, the wet ball milling speed is 60-80 r / min and the time is 12-18 h; Preferably, a dispersant is added during the wet ball milling, and the volume ratio of the dispersant to deionized water is 1:(35-45); Preferably, the drying temperature is 110-130°C; Preferably, the calcination temperature is 1200-1250° C. and the calcination time is 2-6 hours.

6. The preparation method according to claim 4 or 5, characterized in that The raw materials for preparing the LiZn ferrite in step (1) include Li2CO3, ZnO, Fe2O3, TiO2, Bi2O3 and Mn3O4; Preferably, the mass ratio of the powder, deionized water and zirconia balls in the first wet grinding mixing in step (1) is 1:(0.9-1.1):(4.5-5.5); Preferably, the rotation speed of the first wet grinding mixing in step (1) is 60-80 r / min, and the time is 12-18 h; Preferably, in step (1), a dispersant is added to the first wet grinding mixing, and the volume ratio of the dispersant to deionized water is 1:(35-45).

7. The preparation method according to any one of claims 4 to 6, characterized in that The drying temperature in step (1) is 110-130° C. Preferably, after the drying in step (1) and before the pre-calcination, the step of passing through an 80-mesh sieve is further included; Preferably, the pre-calcination temperature in step (1) is 900-950° C. and the pre-calcination time is 2-6 hours.

8. The preparation method according to any one of claims 4 to 7, characterized in that In step (2), the mass ratio of the powder, deionized water, and zirconium oxide balls in the second wet grinding mixture is 1:(0.9-1.1):(4.5-5.5); Preferably, the rotation speed of the second wet grinding mixing in step (2) is 60-80 r / min, and the time is 12-18 h.

9. The preparation method according to any one of claims 4 to 8, characterized in that Step (2) of dehydrating the slurry until the water content is 20-30%; Preferably, the magnetic field of the magnetic field orientation molding in step (2) is ≥1.4T and the pressure is 2.8-3.2MPa; Preferably, the sintering temperature in step (2) is 1150-1250° C. and the sintering time is 4-8 hours.

10. An application of the dual-phase composite ferrite material according to any one of claims 1 to 3, characterized in that: The dual-phase composite ferrite material is used in a self-biased circulator.