1. A microwave ferrite material is characterized in that the composition chemical formula of the microwave ferrite material is Y_3-a-b+dCa_{b- d}Bi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂Wherein a is 0.12-0.18, b is 0.3-0.5, c is 0.3-0.4, and d is 0.1-0.2.

2. A microwave ferrite material in accordance with claim 1, wherein the composition chemical formula of the microwave ferrite material is Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂Wherein a is 0.14-0.16, b is 0.36-0.42, c is 0.35-0.37, and d is 0.12-0.15.

3. The microwave ferrite material of claim 1 or 2, wherein the microwave ferrite is prepared from raw materials including CaCO₃、TiO₂With CaTiO₃；

Preferably, the preparation raw material of the microwave ferrite comprises Y₂O₃、CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃、Al₂O₃ZnO and CaTiO₃。

4. A method of preparing a microwave ferrite as claimed in any one of claims 1 to 3, wherein the method comprises the steps of:

(1) ball-milling and mixing the raw materials according to the formula amount to obtain a mixture;

(2) pre-sintering the mixture obtained in the step (1) to obtain a pre-sintered material;

(3) crushing the pre-sintered material obtained in the step (2), then uniformly mixing the pre-sintered material with a binder, and performing spray drying to obtain microwave ferrite granules;

(4) carrying out compression molding on the microwave ferrite granules obtained in the step (3), then sintering in an oxidizing atmosphere, and carrying out cooling treatment after sintering to obtain a microwave ferrite blank;

(5) and (5) cold rolling the microwave ferrite blank obtained in the step (4), and annealing to obtain the microwave ferrite.

5. The method according to claim 4, wherein the grain size of the mixture obtained in step (1) is less than 1 μm, preferably the average grain size is 0.4-0.8 μm;

preferably, the temperature of the pre-sintering in the step (2) is 700-;

preferably, the sintering in the step (2) is carried out in an oxygen-containing atmosphere with the volume concentration of oxygen being more than or equal to 30%.

6. The method according to claim 4 or 5, wherein the size of the crushed material obtained by the ball milling and crushing in the step (3) is less than 1 μm;

preferably, the addition amount of the binder in the step (3) is 0.5-1 wt% of the microwave ferrite granules;

preferably, the average particle size of the microwave ferrite granules obtained in the step (3) is 20-40 μm.

7. The production method according to any one of claims 4 to 6, wherein the compression molding in step (4) includes: heating to 500-600 ℃ at the speed of 10-30 ℃/min, preserving heat for 1-2h, naturally cooling to room temperature, and then carrying out cold isostatic pressing;

preferably, the pressure of the cold isostatic pressing is 100-200 MPa;

preferably, the oxidizing atmosphere in the step (4) is an oxygen-containing atmosphere with the oxygen volume concentration being more than or equal to 30%;

preferably, the sintering temperature in the step (4) is 1250-;

preferably, the temperature reduction treatment of step (4) comprises: cooling to 350 ℃ at the speed of 20-30 ℃/min, preserving the heat for 1-2h, and then naturally cooling to room temperature.

8. The method according to any one of claims 4 to 7, wherein the cold rolling in step (5) has a deformation of 50 to 60%, and the deformation per pass is 10 to 20%;

preferably, the annealing treatment in the step (5) is raising the temperature to 700-800 ℃ at the speed of 5-8 ℃/min, and then keeping the temperature for 2-3 h.

9. The method according to any one of claims 4 to 8, characterized by comprising the steps of:

(1) ball-milling and mixing the raw materials according to the formula amount to obtain a mixture with the particle size of less than 1 mu m and the average particle size of 0.4-0.8 mu m;

(2) pre-sintering the mixture obtained in the step (1) at the temperature of 700-900 ℃ for 3-5h in an oxygen-containing atmosphere with the volume concentration of oxygen being more than or equal to 30% to obtain a pre-sintered material;

(3) crushing the pre-sintered material obtained in the step (2) until the particle size is less than 1 mu m, then uniformly mixing the pre-sintered material with a binder, and performing spray drying to obtain microwave ferrite granules with the average particle size of 20-40 mu m; the addition amount of the binder is 0.5-1 wt% of the microwave ferrite granules;

(4) heating the microwave ferrite granules obtained in the step (3) to 500-; sintering in an oxygen-containing atmosphere with the oxygen volume concentration of more than or equal to 30% after cold isostatic pressing is finished, and cooling after sintering is finished to obtain a microwave ferrite blank;

the sintering temperature is 1250-;

the cooling treatment comprises the following steps: cooling to 350 ℃ at the speed of 20-30 ℃/min, preserving the heat for 1-2h, and then naturally cooling to room temperature;

(5) and (5) cold-rolling the microwave ferrite blank obtained in the step (4), raising the temperature to 700-800 ℃ at the speed of 5-8 ℃/min, and then preserving the heat for 2-3h to obtain the microwave ferrite.

10. Use of a microwave ferrite material as claimed in any of claims 1 to 3, characterised in that said use comprises use in a circulator.

Background

The anisotropy of the ferrite material is induced by an applied dc bias field that aligns the magnetic dipoles in the ferrite material in the same direction, thereby synthesizing a non-zero magnetic dipole moment and causing the magnetic dipoles to precess at a frequency controlled by the bias field. Meanwhile, a circularly polarized microwave signal in the same direction as precession strongly interacts with a magnetic dipole moment, but a field with opposite polarization only has a weaker interaction, which is called gyromagnetic property of ferrite, and ferrite with gyromagnetic property is called gyromagnetic ferrite, and is commonly called microwave ferrite because the ferrite is widely applied to the field of microwave communication.

The circulator is a multi-port device which transmits incident waves entering any port of the circulator into the next port according to the direction sequence determined by the static bias magnetic field, and the circulator is characterized in that high-frequency signal energy is transmitted in a single direction. The circulator controls electromagnetic waves to be transmitted along a certain annular direction, is mainly used between the output end of the high-frequency power amplifier and a load, and plays the independent and mutually isolated roles. The principle of one-way transmission of the circulator is that microwave ferrite material is adopted, and under the combined action of an external high-frequency wave field and a constant direct-current magnetic field, the material generates gyromagnetic characteristics and strong absorption of electromagnetic wave energy.

For example, CN 210805974U discloses a microwave ferrite circulator, which includes a housing, a foot-guiding stand, a first permanent magnet, a magnetic conductive sheet, a first ferrite, a central conductor, a second ferrite, a ground sheet, a second permanent magnet, and a cover plate, which are sequentially disposed in the housing from bottom to top; the lead frame is arranged separately from the shell, the lead frame is provided with a plurality of extending arms fixed with pins, the side wall of the shell is provided with a plurality of openings, the extending arms of the lead frame extend out of the openings, the permanent magnet is arranged on the lead frame, the magnetic conductive sheet is arranged on a stacking piece formed by the lead frame and the permanent magnet, the first ferrite and the second ferrite clamp the central conductor in the middle to form a wire clamping layer, the central conductor is provided with the extending arms correspondingly connected with the pins, the grounding sheet is arranged above the second ferrite, the second permanent magnet is arranged above the grounding sheet, and the cover plate is positioned on the top.

With the rapid development of communication technology, the requirements for miniaturization and light weight of devices are more and more urgent, and the volume of ferrite components is much higher than that of other components, so the task of miniaturization and light weight is particularly important. The dielectric constant epsilon, which is one of the main parameters of device design, is closely related to the device size. Since the wavelength of a medium through which an electromagnetic wave propagates in the medium is inversely proportional to the square root of the dielectric constant, increasing the dielectric constant of a material is an important means for miniaturization of a device.

The dielectric constant of the ferrite material commonly used in the microwave communication field is generally between 12 and 16. By adjusting the formula and doping certain elements, the dielectric constant of the ferrite can be improved, but the ferromagnetic resonance linewidth is increased, the Curie temperature is reduced, and the ferrite loses the practical value. The width of the ferromagnetic resonance line is an important factor influencing the microwave transmission loss, and the ferromagnetic resonance line is large in width, so that microwave signals generate more loss in the transmission process in the microwave device, namely, the loss is large at ordinary times. The technical difficulty is that the dielectric constant of ferrite is required to be improved, and other performances of the ferrite are required to be kept not to be deteriorated, so that the problem of the ferrite material is solved, and obstacles are eliminated for miniaturization and light weight of communication devices.

The development of communication technology needs the development of circulator products from the current mainstream diameter of 10mm to 7mm, even 5mm, so that a proper microwave ferrite material needs to be selected, the purpose of reducing the size of the microwave ferrite can be realized, and the requirement of unchanged basic performance can be met, namely the requirement that the size of a microwave ferrite magnetic ring is controlled to be less than 7mm, the dielectric constant is controlled to be 14-31, the saturation magnetization 4 pi Ms is 1200 + 2000Gs, the Curie temperature is not lower than 200 ℃, the dielectric loss tangent tan delta is less than or equal to 0.0002, and the Delta H is less than or equal to 50Oe is met, so that the requirements of 5G communication on device miniaturization and low power consumption are met.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a microwave ferrite material and a preparation method and application thereof, the microwave ferrite material prepared by the invention can meet the requirements that the dielectric constant is controlled to be 14-31, the saturation magnetization 4 pi Ms is 1200-2000Gs, the Curie temperature is not lower than 200 ℃, the dielectric loss tangent tan delta is not more than 0.0002 and the Delta H is not more than 50Oe, and the diameter of the microwave ferrite material can be kept not more than 7 mm.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a microwave ferrite material, wherein the composition chemical formula of the microwave ferrite material is Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂Wherein a is 0.12-0.18, b is 0.3-0.5, c is 0.3-0.4, and d is 0.1-0.2.

The invention needs to ensure that the saturation magnetization intensity 4 pi Ms of the microwave ferrite material is 1200-2000Gs, the Curie temperature is not lower than 200 ℃, the ferromagnetic resonance line width Delta H is not more than 50Oe, the dielectric constant is 14-31 and the dielectric loss tangent tan delta is not more than 0.0002. The microwave ferrite material provided by the invention is garnet type ferrite material Y₃Fe₅O₁₂Prepared on the basis that the magnetism of garnet-type ferrites is derived from Fe in a tetrahedral sublattice³⁺Ionic magnetic moment of (1), and octahedral sublattice Fe³⁺With dodecahedral sublattice Y³⁺The adjustment of saturation magnetization can be realized by using nonmagnetic ions to replace Fe in tetrahedral sublattice and octahedral sublattice due to the reverse arrangement of ion magnetic moments, but the Curie temperature, the dielectric constant and the ferromagnetic resonance line width are difficult to ensure to meet the requirements at the same time.

The Curie temperature of ferrite materials is derived from the octahedral and tetrahedral Fe positions³⁺Exchange of Fe at that position with a non-magnetic ion³⁺Fe which leads to both tetrahedral and octahedral sublattices³⁺The superexchange function between the two is weakened, so that the Curie temperature is reduced.

The ferromagnetic resonance linewidth is not only affected by the constituent materials therein, but also related to the void fraction and surface roughness of the resulting microwave ferrite material.

Dielectric constant and dielectric loss are mainly related to Fe²⁺The ion content is related to the element ions introduced into the microwave ferrite, but the introduction of improper element ions can cause the properties of the microwave ferrite such as ferromagnetic resonance line width to be sharply deteriorated, therebyLosing the use value.

In view of the above, the present invention provides a compound represented by the formula Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂The microwave ferrite material of (1), which passes Ca²⁺、Zn²⁺、Bi³⁺、Al³⁺And Ti⁴⁺The specific synergistic addition of the components can meet the requirements that the dielectric constant is controlled to be 14-31, the saturation magnetization 4 pi Ms is 1200-2000Gs, the Curie temperature is not lower than 200 ℃, the dielectric loss tangent tan delta is not more than 0.0002 and the Delta H is not more than 50Oe when the size of the prepared microwave ferrite material is less than 7 mm.

Y provided by the invention_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂In the above formula, a is 0.12 to 0.18, for example, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17 or 0.18, but is not limited to the values listed, and other values not listed in the numerical range are also applicable, and preferably 0.14 to 0.16.

Y provided by the invention_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂In the above formula, b is 0.3 to 0.5, and may be, for example, 0.3, 0.32, 0.35, 0.36, 0.4, 0.42, 0.45, 0.48 or 0.5, but is not limited to the above-mentioned values, and other values not shown in the above-mentioned numerical ranges are also applicable, and preferably 0.36 to 0.42.

Y provided by the invention_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂In the above range, c is 0.3 to 0.4, and may be, for example, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39 or 0.4, but is not limited to the above-mentioned values, and other values not shown in the above range are also applicable, and preferably 0.35 to 0.37.

Y provided by the invention_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂In this case, d is from 0.1 to 0.2, and may be, for example, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19 or0.2, but not limited to the values cited, and other values within the range of values not cited are equally applicable, preferably 0.12 to 0.15.

Preferably, the raw material for preparing the microwave ferrite comprises CaCO₃、TiO₂With CaTiO₃。

In the preparation raw materials of the microwave ferrite, the sources of Ca and Ti are mainly CaTiO₃，CaCO₃And TiO₂The addition of (3) is used for regulating and controlling the proportion of Ca and Ti to enable the Ca and Ti to meet the requirement of a chemical formula.

Sources of the remaining elements in the microwave ferrite of the present invention include oxides and/or salts of each element. Illustratively, the source of Y comprises yttrium oxide and/or yttrium nitrate.

Preferably, the preparation raw material of the microwave ferrite comprises Y₂O₃、CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃、Al₂O₃ZnO and CaTiO₃。

In a second aspect, the present invention provides a method for preparing the microwave ferrite according to the first aspect, wherein the method comprises the following steps:

(1) ball-milling and mixing the raw materials according to the formula amount to obtain a mixture;

(2) pre-sintering the mixture obtained in the step (1) to obtain a pre-sintered material;

(3) ball-milling and crushing the pre-sintered material obtained in the step (2), then uniformly mixing the pre-sintered material with a binder, and performing spray drying to obtain microwave ferrite granules;

(4) carrying out compression molding on the microwave ferrite granules obtained in the step (3), then sintering in an oxidizing atmosphere, and carrying out cooling treatment after sintering to obtain a microwave ferrite blank;

(5) and (5) cold rolling the microwave ferrite blank obtained in the step (4), and annealing to obtain the microwave ferrite.

The preparation method is also important for obtaining the microwave ferrite material with the dielectric constant, the dielectric loss, the saturation magnetization, the Curie temperature and the ferromagnetic resonance line width meeting the requirements. The invention adopts the spray drying method for granulation, improves the granulation efficiency and stability, and the granules obtained by spray drying are close to spherical, have good fluidity, are beneficial to the subsequent compression molding operation and are beneficial to reducing the ferromagnetic resonance line width of the obtained microwave ferrite material.

The invention is sintered in the oxidizing atmosphere to obtain the microwave ferrite blank, and the Fe in the obtained microwave ferrite can be ensured without adding excessive Fe element³⁺And (4) content, and avoids the increase of dielectric loss. Then, a small amount of microcrystal structures are formed in the microwave ferrite material through cooling treatment and cold rolling treatment, and the low ferromagnetic resonance line width of the obtained microwave ferrite material is further ensured under the conditions of high saturation magnetization and high dielectric constant.

Preferably, the particle size of the mix obtained in step (1) is <1 μm, preferably the average particle size is 0.4-0.8. mu.m, which may be, for example, 0.4. mu.m, 0.5. mu.m, 0.6. mu.m, 0.7. mu.m or 0.8. mu.m, but is not limited to the values listed, and other values not listed within the range of values are equally applicable.

The ball milling and mixing in the step (1) are carried out in a grinding machine, compared with the traditional ball milling method, the grinding machine can improve the mixing efficiency, and can ensure that the particle size of the powder obtained after grinding is less than 1 μm, which is superior to the particle size of more than 5 μm obtained by the traditional ball milling.

Preferably, the temperature of the pre-sintering in step (2) is 700-900 ℃, for example 700 ℃, 750 ℃, 800 ℃, 850 ℃ or 900 ℃, but not limited to the recited values, and other unrecited values in the range of values are also applicable; the presintering time is 3-5h, for example 3h, 3.5h, 4h, 4.5h or 5h, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.

Preferably, the sintering in the step (2) is carried out in an oxygen-containing atmosphere with the volume concentration of oxygen being more than or equal to 30%.

The oxygen-containing atmosphere has an oxygen concentration of 30% or more by volume, for example, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%, but is not limited to the recited values, and other values not recited within the numerical range are also applicable. When the oxygen-containing atmosphere of the present invention has a volume concentration of oxygen other than 100%, the oxygen-containing atmosphere may include nitrogen and/or an inert gas in addition to oxygen.

Preferably, the particle size of the crushed material obtained by the crushing in the step (3) is less than 1 μm.

Preferably, the binder added in step (3) is 0.5-1 wt% of the microwave ferrite particles, for example, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt% or 1 wt%, but not limited to the enumerated values, and other values not enumerated in the numerical range are also applicable.

The binder of the present invention is a binder that is conventional in the art as long as it can achieve the binding granulation, and the present invention is not limited to a specific kind of binder.

Preferably, the microwave ferrite granules obtained in step (3) have an average particle size of 20-40 μm, such as 20 μm, 25 μm, 30 μm, 35 μm or 40 μm, but not limited to the values listed, and other values not listed in the numerical range are also applicable.

Preferably, the compression molding of step (4) includes: heating to 500-600 ℃ at the speed of 10-30 ℃/min, preserving heat for 1-2h, naturally cooling to room temperature, and then carrying out cold isostatic pressing.

The traditional hot isostatic pressing needs to be carried out under the conditions of high temperature and high pressure, and due to the action of the high pressure on the surface of the microwave ferrite blank under the high temperature condition, the size of crystal grains on the surface of the microwave ferrite blank is abnormally changed, which is not beneficial to reducing the ferromagnetic resonance line width of the finally obtained microwave ferrite. The invention adopts a specific compression molding process, which can overcome the defects; in addition, the porosity of the finally obtained microwave ferrite material can be reduced and the ferromagnetic resonance line width can be reduced by combining rapid temperature rise and cold isostatic pressing.

In the compression molding in the step (4), the heating rate is 10-30 ℃/min, for example, 10 ℃/min, 15 ℃/min, 20 ℃/min, 25 ℃/min or 30 ℃/min, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.

In the step (4) of compression molding, the temperature at the end point of temperature rise is 500-.

Preferably, the cold isostatic pressing pressure is 100-200MPa, and may be, for example, 100MPa, 110MPa, 120MPa, 130MPa, 140MPa, 150MPa, 160MPa, 170MPa, 180MPa, 190MPa or 200MPa, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.

Preferably, the oxidizing atmosphere in the step (4) is an oxygen-containing atmosphere with the oxygen volume concentration being more than or equal to 30%.

The oxygen-containing atmosphere has an oxygen concentration of 30% or more by volume, for example, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%, but is not limited to the recited values, and other values not recited within the numerical range are also applicable. When the oxygen-containing atmosphere of the present invention has a volume concentration of oxygen other than 100%, the oxygen-containing atmosphere may include nitrogen and/or an inert gas in addition to oxygen.

Preferably, the sintering temperature in step (4) is 1250-; the sintering time is 4-6h, for example 4h, 4.5h, 5h, 5.5h or 6h, but is not limited to the values listed, and other values not listed in the numerical range are equally applicable.

Preferably, the temperature reduction treatment of step (4) comprises: cooling to 350 ℃ at the speed of 20-30 ℃/min, preserving the heat for 1-2h, and then naturally cooling to room temperature.

The temperature of the temperature reduction treatment is 20-30 deg.C/min, for example, 20 deg.C/min, 21 deg.C/min, 22 deg.C/min, 23 deg.C/min, 24 deg.C/min, 25 deg.C/min, 26 deg.C/min, 27 deg.C/min, 28 deg.C/min, 29 deg.C/min or 30 deg.C/min, but is not limited to the values listed, and other values not listed in the range of values are also applicable.

The temperature of the temperature reduction treatment is 300-350 ℃, for example, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃ or 350 ℃, but not limited to the values listed, and other values not listed in the value range are also applicable.

The temperature reduction treatment is carried out for 1-2h, for example, 1h, 1.2h, 1.5h, 1.8h or 2h, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.

Preferably, the cold rolling in step (5) has a deformation of 50-60%, for example 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, or 60%, but not limited to the recited values, and other values not recited in the range of values are equally applicable; the deformation per pass is 10 to 20%, and may be, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.

Preferably, the annealing treatment in the step (5) is raising the temperature to 700-800 ℃ at the speed of 5-8 ℃/min, and then keeping the temperature for 2-3 h.

The temperature rise rate of the annealing treatment in the step (5) is 5-8 ℃/min, for example, 5 ℃/min, 6 ℃/min, 7 ℃/min or 8 ℃/min, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.

The temperature of the annealing treatment in step (5) is 700-.

The heat preservation time of the annealing treatment in the step (5) is 2-3h, for example, 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, but not limited to the enumerated values, and other unrecited values in the numerical range are also applicable.

As a preferable technical solution of the preparation method according to the second aspect of the present invention, the preparation method comprises the steps of:

(1) ball-milling and mixing the raw materials according to the formula amount to obtain a mixture with the particle size of less than 1 mu m and the average particle size of 0.4-0.8 mu m;

(2) pre-sintering the mixture obtained in the step (1) at the temperature of 700-900 ℃ for 3-5h in an oxygen-containing atmosphere with the volume concentration of oxygen being more than or equal to 30% to obtain a pre-sintered material;

(3) crushing the pre-sintered material obtained in the step (2) until the particle size is less than 1 mu m, then uniformly mixing the pre-sintered material with a binder, and performing spray drying to obtain microwave ferrite granules with the average particle size of 20-40 mu m; the addition amount of the binder is 0.5-1 wt% of the microwave ferrite granules;

(4) heating the microwave ferrite granules obtained in the step (3) to 500-; sintering in an oxygen-containing atmosphere with the oxygen volume concentration of more than or equal to 30% after cold isostatic pressing is finished, and cooling after sintering is finished to obtain a microwave ferrite blank;

the sintering temperature is 1250-;

the cooling treatment comprises the following steps: cooling to 350 ℃ at the speed of 20-30 ℃/min, preserving the heat for 1-2h, and then naturally cooling to room temperature;

(5) and (5) cold-rolling the microwave ferrite blank obtained in the step (4), raising the temperature to 700-800 ℃ at the speed of 5-8 ℃/min, and then preserving the heat for 2-3h to obtain the microwave ferrite.

In a third aspect, the present invention provides a use of a microwave ferrite material as described in the first aspect, said use comprising use in a circulator.

The microwave ferrite material provided by the invention can meet the requirements that the dielectric constant is controlled to be 14-31, the saturation magnetization 4 pi Ms is 1200-2000Gs, the Curie temperature is not lower than 200 ℃, the dielectric loss tangent tan delta is not more than 0.0002, and the Delta H is not more than 50Oe, the diameter can be below 7mm, and the requirements of miniaturization and low power consumption of a circulator by 5G communication are met.

The recitation of numerical ranges herein includes not only the above-recited numerical values, but also any numerical values between non-recited numerical ranges, and is not intended to be exhaustive or to limit the invention to the precise numerical values encompassed within the range for brevity and clarity.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention provides a compound with a chemical formula of Y_3-a-bCa_eBi_aTi_bFe_5-c-dAl_c-eZn_dO₁₂The microwave ferrite material of (1), which passes Ca²⁺、Zn²⁺、Bi³⁺、Al³⁺And Ti⁴⁺The specific synergistic addition of the components can meet the requirements that the dielectric constant is controlled to be 14-31, the saturation magnetization intensity 4 pi Ms is 1200-2000Gs, the Curie temperature is not lower than 200 ℃, the dielectric loss tangent tan delta is not more than 0.0002 and the Delta H is not more than 50Oe when the size of the prepared microwave ferrite material is less than 7 mm;

(2) the invention adopts the spray drying method for granulation, improves the granulation efficiency and stability, and the granules obtained by spray drying are close to spherical, have good fluidity, are beneficial to the subsequent compression molding operation and are beneficial to reducing the ferromagnetic resonance line width of the obtained microwave ferrite material;

(3) the invention is sintered in the oxidizing atmosphere to obtain the microwave ferrite blank, and the Fe in the obtained microwave ferrite can be ensured without adding excessive Fe element³⁺Content, avoiding the increase of dielectric loss; then, a small amount of microcrystal structures are formed in the microwave ferrite material through cooling treatment and cold rolling treatment, so that the low ferromagnetic resonance line width of the obtained microwave ferrite material is further ensured under the conditions of high saturation magnetization and dielectric constant;

(4) the traditional hot isostatic pressing needs to be carried out under the conditions of high temperature and high pressure, and due to the effect of the high pressure on the surface of the microwave ferrite blank under the high temperature condition, the grain size on the surface of the microwave ferrite blank is abnormally changed, which is not beneficial to reducing the ferromagnetic resonance line width of the finally obtained microwave ferrite.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments.

Example 1

The present embodiment provides a microwave ferriteThe preparation method of the bulk material comprises the step of preparing the microwave ferrite material with the chemical formula of Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂Wherein a is 0.15, b is 0.4, c is 0.36, d is 0.14; the raw material for preparing the microwave ferrite comprises Y₂O₃、CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃、Al₂O₃ZnO and CaTiO₃；

The preparation method comprises the following steps:

(1) ball-milling the mixed raw materials in a grinding machine according to the formula amount to obtain a mixture with the particle size of less than 1 mu m and the average particle size of 0.6 mu m;

(2) pre-sintering the mixture obtained in the step (1) for 4 hours at 800 ℃ in an oxygen atmosphere to obtain a pre-sintered material;

(3) crushing the pre-sintered material obtained in the step (2) in a grinding machine until the particle size is less than 1 mu m, then uniformly mixing the pre-sintered material with a binder, and performing spray drying to obtain microwave ferrite granules with the average particle size of 30 mu m; the addition amount of the binder is 0.8 wt% of the microwave ferrite granules;

(4) heating the microwave ferrite granules obtained in the step (3) to 550 ℃ at the speed of 20 ℃/min, preserving heat for 1.5h, naturally cooling to room temperature, and then carrying out cold isostatic pressing under the condition of 150 MPa; sintering in an oxygen atmosphere after cold isostatic pressing is finished, and cooling after sintering is finished to obtain a microwave ferrite blank;

the sintering temperature is 1320 ℃, and the sintering time is 5 h;

the cooling treatment comprises the following steps: cooling to 320 ℃ at the speed of 25 ℃/min, preserving heat for 1.5h, and then naturally cooling to room temperature;

(5) cold rolling the microwave ferrite blank obtained in the step (4), wherein the total cold rolling deformation is 60%, and the deformation of each pass is 20%; and then raising the temperature to 750 ℃ at the speed of 6 ℃/min, and then preserving the temperature for 2.5 hours to obtain the microwave ferrite.

Example 2

The present embodiment provides a method for preparing a microwave ferrite material, a group of the microwave ferrite materialsHas the chemical formula of Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂Wherein a is 0.14, b is 0.36, c is 0.35, d is 0.12; the raw material for preparing the microwave ferrite comprises Y₂O₃、CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃、Al₂O₃ZnO and CaTiO₃；

The preparation method of this example is the same as example 1.

Example 3

The embodiment provides a preparation method of a microwave ferrite material, wherein the composition chemical formula of the microwave ferrite material is Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂Wherein a is 0.16, b is 0.42, c is 0.37, d is 0.15; the raw material for preparing the microwave ferrite comprises Y₂O₃、CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃、Al₂O₃ZnO and CaTiO₃；

The preparation method of this example is the same as example 1.

Example 4

The embodiment provides a preparation method of a microwave ferrite material, wherein the composition chemical formula of the microwave ferrite material is Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂Wherein a is 0.12, b is 0.3, c is 0.3, d is 0.2; the raw material for preparing the microwave ferrite comprises Y₂O₃、CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃、Al₂O₃ZnO and CaTiO₃；

The preparation method of this example is the same as example 1.

Example 5

The embodiment provides a preparation method of a microwave ferrite material, and the composition of the microwave ferrite materialHas a chemical formula of Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂Wherein a is 0.18, b is 0.5, c is 0.4, d is 0.1; the raw material for preparing the microwave ferrite comprises Y₂O₃、CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃、Al₂O₃ZnO and CaTiO₃；

The preparation method of this example is the same as example 1.

Example 6

This example provides a method for preparing a microwave ferrite material, except that the raw material for preparing the microwave ferrite is Y₂O₃、CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃、Al₂O₃The procedure of example 1 was repeated except for the ZnO.

Example 7

This example provides a method for preparing a microwave ferrite material, except for the microwave ferrite material Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂The same as example 1 except that b in (1) was 0.25.

Example 8

This example provides a method for preparing a microwave ferrite material, except for the microwave ferrite material Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂The same as example 1 except that b in (1) was 0.55.

Example 9

This example provides a method for preparing a microwave ferrite material, except for the microwave ferrite material Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂The same as example 1 except that d in (1) was 0.08.

Example 10

This exampleA method for preparing a microwave ferrite material is provided, except for the microwave ferrite material Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂The same as example 1 except that d in (1) is 0.25.

Example 11

The embodiment provides a preparation method of a microwave ferrite material, the composition and preparation raw materials of the microwave ferrite material are the same as those of the embodiment 1, and the preparation method comprises the following steps:

(1) ball-milling the mixed raw materials in a grinding machine according to the formula amount to obtain a mixture with the particle size of less than 1 mu m and the average particle size of 0.4 mu m;

(2) pre-sintering the mixture obtained in the step (1) at 750 ℃ for 4.5 hours in an oxygen atmosphere to obtain a pre-sintered material;

(3) crushing the pre-sintered material obtained in the step (2) in a grinding machine until the particle size is less than 1 mu m, then uniformly mixing the pre-sintered material with a binder, and performing spray drying to obtain microwave ferrite granules with the average particle size of 20 mu m; the addition amount of the binder is 0.5 wt% of the microwave ferrite granules;

(4) heating the microwave ferrite granules obtained in the step (3) to 500 ℃ at the speed of 10 ℃/min, preserving the heat for 2h, naturally cooling to room temperature, and then carrying out cold isostatic pressing under the condition of 100 MPa; sintering in an oxygen atmosphere after cold isostatic pressing is finished, and cooling after sintering is finished to obtain a microwave ferrite blank;

the sintering temperature is 1250 ℃, and the sintering time is 6 h;

the cooling treatment comprises the following steps: cooling to 350 ℃ at the speed of 20 ℃/min, preserving heat for 1h, and then naturally cooling to room temperature;

(5) cold rolling the microwave ferrite blank obtained in the step (4), wherein the total cold rolling deformation is 50%, and the deformation of each pass is 10%; and then heating to 700 ℃ at the speed of 5 ℃/min, and then preserving heat for 3h to obtain the microwave ferrite.

Example 12

The embodiment provides a preparation method of a microwave ferrite material, the composition and preparation raw materials of the microwave ferrite material are the same as those of the embodiment 1, and the preparation method comprises the following steps:

(1) ball-milling the mixed raw materials in a grinding machine according to the formula amount to obtain a mixture with the particle size of less than 1 mu m and the average particle size of 0.8 mu m;

(2) pre-sintering the mixture obtained in the step (1) for 3.5 hours at 850 ℃ in an oxygen atmosphere to obtain a pre-sintered material;

(3) crushing the pre-sintered material obtained in the step (2) in a grinding machine until the particle size is less than 1 mu m, then uniformly mixing the pre-sintered material with a binder, and performing spray drying to obtain microwave ferrite granules with the average particle size of 40 mu m; the addition amount of the binder is 1 wt% of the microwave ferrite granules;

(4) heating the microwave ferrite granules obtained in the step (3) to 600 ℃ at the speed of 30 ℃/min, preserving the heat for 1h, naturally cooling to room temperature, and then carrying out cold isostatic pressing under the condition of 200 MPa; sintering in an oxygen atmosphere after cold isostatic pressing is finished, and cooling after sintering is finished to obtain a microwave ferrite blank;

the sintering temperature is 1400 ℃, and the sintering time is 4 h;

the cooling treatment comprises the following steps: cooling to 300 ℃ at the speed of 30 ℃/min, preserving heat for 2h, and then naturally cooling to room temperature;

(5) cold rolling the microwave ferrite blank obtained in the step (4), wherein the total cold rolling deformation is 54%, and the deformation of each pass is 18%; and then heating to 800 ℃ at the speed of 8 ℃/min, and then preserving heat for 2h to obtain the microwave ferrite.

Example 13

The embodiment provides a preparation method of a microwave ferrite material, the composition and preparation raw materials of the microwave ferrite material are the same as those of the embodiment 1, and the preparation method comprises the following steps:

(1) ball-milling the mixed raw materials in a grinding machine according to the formula amount to obtain a mixture with the particle size of less than 1 mu m and the average particle size of 0.6 mu m;

(2) pre-sintering the mixture obtained in the step (1) for 3 hours at 700 ℃ in an oxygen atmosphere to obtain a pre-sintered material;

(3) crushing the pre-sintered material obtained in the step (2) in a grinding machine until the particle size is less than 1 mu m, then uniformly mixing the pre-sintered material with a binder, and performing spray drying to obtain microwave ferrite granules with the average particle size of 30 mu m; the addition amount of the binder is 0.8 wt% of the microwave ferrite granules;

(4) performing cold isostatic pressing on the microwave ferrite granules obtained in the step (3) under the condition of 150 MPa; sintering in an oxygen atmosphere after cold isostatic pressing is finished, and cooling after sintering is finished to obtain a microwave ferrite blank;

the sintering temperature is 1320 ℃, and the sintering time is 5 h;

the cooling treatment comprises the following steps: cooling to 320 ℃ at the speed of 25 ℃/min, preserving heat for 1.5h, and then naturally cooling to room temperature;

(5) cold rolling the microwave ferrite blank obtained in the step (4), wherein the total cold rolling deformation is 60%, and the deformation of each pass is 20%; and then raising the temperature to 750 ℃ at the speed of 6 ℃/min, and then preserving the temperature for 2.5 hours to obtain the microwave ferrite.

Example 14

The embodiment provides a preparation method of a microwave ferrite material, the composition and preparation raw materials of the microwave ferrite material are the same as those of the embodiment 1, and the preparation method comprises the following steps:

(1) ball-milling the mixed raw materials in a grinding machine according to the formula amount to obtain a mixture with the particle size of less than 1 mu m and the average particle size of 0.6 mu m;

(2) pre-sintering the mixture obtained in the step (1) for 5 hours at 900 ℃ in an oxygen atmosphere to obtain a pre-sintered material;

(3) crushing the pre-sintered material obtained in the step (2) in a grinding machine until the particle size is less than 1 mu m, then uniformly mixing the pre-sintered material with a binder, and performing spray drying to obtain microwave ferrite granules with the average particle size of 30 mu m; the addition amount of the binder is 0.8 wt% of the microwave ferrite granules;

(4) heating the microwave ferrite granules obtained in the step (3) to 550 ℃ at the speed of 20 ℃/min, preserving heat for 1.5h, naturally cooling to room temperature, and then carrying out cold isostatic pressing under the condition of 150 MPa; sintering in an oxygen atmosphere after cold isostatic pressing is finished, and naturally cooling to room temperature after sintering is finished to obtain a microwave ferrite blank;

(5) cold rolling the microwave ferrite blank obtained in the step (4), wherein the total cold rolling deformation is 60%, and the deformation of each pass is 20%; and then raising the temperature to 750 ℃ at the speed of 6 ℃/min, and then preserving the temperature for 2.5 hours to obtain the microwave ferrite.

Comparative example 1

This comparative example provides a preparation method of a microwave ferrite material, which is the same as that of example 1 except that ZnO is replaced with CuO in an equimolar amount.

Comparative example 2

This comparative example provides a process for preparing a microwave ferrite material, which is the same as example 1 except that ZnO is replaced with an equimolar amount of MnO.

Comparative example 3

This comparative example provides a process for the preparation of a microwave ferrite material except for the addition of TiO₂Replacement with an equimolar amount of ZrO₂Otherwise, the same procedure as in example 1 was repeated.

Comparative example 4

This comparative example provides a method of preparing a microwave ferrite material, which is the same as example 1 except that only the annealing treatment is performed in step (5).

Curie temperature (Tc), dielectric constant (. epsilon.), saturation magnetization (4 π Ms) and ferromagnetic resonance line width (. DELTA.H) for the microwave ferrite materials provided in examples 1-14 and comparative examples 1-4. Measuring Curie temperature and saturation magnetization by using a vibrating sample magnetometer; testing the dielectric constant according to the IEC60556 standard, wherein the testing frequency is 10.7GHz, and the sample size is 1.6 mm; the ferromagnetic resonance line width was measured according to GB/T9633-88, and the results are shown in Table 1.

TABLE 1

In summary, the present invention provides a chemical formula of Y_3-a-b+dCa_b-dBi_aTi_bAl_cZn_dFe_5-b-c-dO₁₂The microwave ferrite material of (1), which passes Ca²⁺、Zn²⁺、Bi³⁺、Al³⁺And Ti⁴⁺The specific synergistic addition of the components can meet the requirements that the dielectric constant is controlled to be 14-31, the saturation magnetization intensity 4 pi Ms is 1200-2000Gs, the Curie temperature is not lower than 200 ℃, the dielectric loss tangent tan delta is not more than 0.0002 and the Delta H is not more than 50Oe when the size of the prepared microwave ferrite material is less than 7 mm; the invention adopts the spray drying method for granulation, improves the granulation efficiency and stability, and the granules obtained by spray drying are close to spherical, have good fluidity, are beneficial to the subsequent compression molding operation and are beneficial to reducing the ferromagnetic resonance line width of the obtained microwave ferrite material; the invention is sintered in the oxidizing atmosphere to obtain the microwave ferrite blank, and the Fe in the obtained microwave ferrite can be ensured without adding excessive Fe element³⁺Content, avoiding the increase of dielectric loss; then, a small amount of microcrystal structures are formed in the microwave ferrite material through cooling treatment and cold rolling treatment, so that the low ferromagnetic resonance line width of the obtained microwave ferrite material is further ensured under the conditions of high saturation magnetization and dielectric constant; the traditional hot isostatic pressing needs to be carried out under the conditions of high temperature and high pressure, and due to the effect of the high pressure on the surface of the microwave ferrite blank under the high temperature condition, the grain size on the surface of the microwave ferrite blank is abnormally changed, which is not beneficial to reducing the ferromagnetic resonance line width of the finally obtained microwave ferrite.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.