Fabrication of low linewidth W-type hexagonal microwave ferrite material

Abstract

This paper discloses a method for producing a W-type hexagonal microwave ferrite material with low linewidth. The method includes weighing → first ball milling → drying → first sintering → second ball milling → granulation molding → second sintering to obtain a W-type hexagonal microwave ferrite material with low linewidth. The method of the present application replaces some Fe ions with rare earth element Gd, and obtains appropriate saturation magnetization, remanence and linewidth by utilizing the electromagnetic properties and compensation points of Gd and Fe, and also adds an appropriate amount of low melting point fluxes Bi2O3, V2O5, SiO2 and ZnO to improve the microstructure of the W-type hexagonal microwave ferrite material, reduce pores, reduce linewidth and increase remanence. The method of the present application has a stable process, good reproducibility and is suitable for mass production.

Description

[Technical Field]

[0001] Embodiments of the present application relate to the field of magnetic materials, for example, methods for producing low linewidth W-type hexagonal microwave ferrite materials. [Background technology]

[0002] With the rapid development of electronic information technology, the application of radar in military and civilian fields is becoming increasingly important. Active phased array radar employs a large number of radiating units arranged in an array, with each radiating unit connected to a transmitting / receiving component. The transmitting / receiving component is the core component of the active phased array radar antenna array element, and must complete RF signal transmission and reception within an extremely small volume. Although these components are highly integrated using monolithic microwave integrated circuit technology, they are limited by the size of the circulator and have not yet been miniaturized or integrated into a chip. Due to its nonreciprocity, the circulator is an essential component connecting the three modules of the transmitting / receiving component—the transmitter, antenna, and receiver—in the transmitting / receiving component. However, conventional circulators designed based on garnet and spinel ferrites require a large external permanent magnet to provide a bias magnetic field to achieve the circulator function. Furthermore, the higher the operating frequency of the circulator, the larger the volume of the permanent magnet required. Therefore, reducing the size of the circulator is an unavoidable and important issue for achieving further miniaturization and integration of the transmitting / receiving components.

[0003] CN106747391A discloses a method for manufacturing a circulator substrate based on a casting process, which includes the following steps: 1. Main raw material formula: Y 3-x Ca x Sn x Fe 5-x O 12(x=0.06) is used, 2. Primary ball milling, 3. Pre-firing: Pre-firing at 1000-1200°C and keeping warm for 1-3 hours, 4. Doping: Adding additives of 0.2wt% Bi2O3 and 0.10wt% BaTiO3, 5. Secondary ball milling: Adding 40-50wt% organic binder and 40-50wt% absolute ethanol to the powder material and ball milling for 4-8 hours, 6. Casting: Casting the slurry to obtain a green film tape with a thickness of 100-120μm, 7. Lamination: Depending on the thickness needs, the green film tape is laminated into 8-15 layers and press-molded at 6MPa, 8. Sintering: Keeping warm in an air atmosphere at 1360-1440°C for 4 hours. This method allows for the production of smooth ferrite dielectric substrates for circulators with different thicknesses, and has the advantages of being suitable for the X-band, with good temperature stability, small line width, and low dielectric loss.

[0004] CN102584200A discloses an ultra-low loss, narrow linewidth microwave ferrite material and its manufacturing method, the main phase of the material is a garnet structure, and the chemical formula is Y 3-2x-y Ca 2x+y Fe 5-x-y-z V x Zr y Al z O 12 where x≦0.25, y≦0.25, and z≦0.25 are satisfied. The manufacturing method involves stoichiometrically calculating and weighing the raw materials, followed by vibrating ball milling, calcination, coarse grinding with a vibrating mill, fine grinding with a sand mill, spray granulation, press molding, and sintering. Tests have shown that the ferromagnetic resonance linewidth of the obtained material, ΔH≦1.27 KA / m, and the dielectric loss, tgδe≦0.5×10 -4 The insertion loss of the attached microwave device is ≦0.21 dB, its stability and reliability are greatly improved, and the range of application is expanded. The fabricated microwave ferrite device has the advantages of a wide operating band and low insertion loss.

[0005] CN111732427A discloses a hexagonal ferrite material with low ferromagnetic resonance linewidth for a self-biased circulator, which is composed of a main component and a doping component, wherein the main component includes (6.5-7) mol Fe2O3, (1-1.17) mol BaCO3, and (0-1) mol Ga2O3, and the doping component includes (0.01-1) wt% CuO, (0.01-3) wt% Bi2O3, and (0.01-1.5) wt% B2O3. The present invention also discloses a method for manufacturing the above material, which has a high anisotropy field, high saturation magnetization, a low ferromagnetic resonance linewidth, and a suitable coercive force. The manufacturing method is simple and easy to operate. The high anisotropy field allows it to replace an external permanent magnet in a circulator, reducing the size of the circulator and improving the operating frequency of the device. The low ferromagnetic resonance linewidth can effectively reduce the loss of a self-biased circulator.

[0006] Current hexagonal ferrite materials have high ferromagnetic resonance linewidths and high losses, making them unable to meet new engineering demands.

[0007] Therefore, the development of a method for producing W-type hexagonal microwave ferrite material with low linewidth is of great significance. Summary of the Invention [Problem to be solved by the invention]

[0008] The following is a summary of the subject matter described in detail in the present text. This summary does not limit the scope of the claims. [Means for solving the problem]

[0009] To solve the above technical problems, an embodiment of the present application provides a method for manufacturing a W-type hexagonal microwave ferrite material with a low linewidth. A part of Fe ions is replaced by a rare earth element Gd, and appropriate saturation magnetization, residual magnetic permeability, and linewidth are obtained by utilizing the electromagnetic characteristics and compensation points of Gd and Fe. Moreover, by adding an appropriate amount of low melting point fluxes of Bi2O3, V2O5, SiO2, and ZnO, the microstructure of the W-type hexagonal microwave ferrite material is improved, pores are reduced, the linewidth is reduced, and the residual magnetic permeability is increased. The manufacturing method according to the present application has a stable process, good reproducibility, and is suitable for mass production.

[0010] An embodiment of the present application is a method for manufacturing a W-type hexagonal microwave ferrite material with a low linewidth, comprising: Chemical formula BaGd x Ni2Fe (16~x) O 27 (where 0.1 < x < 0.25), after calculating and weighing raw materials BaCO3, Gd2O3, Ni2O, and Fe2O3, performing a first ball milling process to obtain a slurry after the first ball milling with a particle size X50 of 0.9 - 1.2 μm, step (1); Sequentially performing drying and a first sintering process at a temperature of 1200 - 1280 °C on the slurry after the first ball milling to obtain a mixed powder material, step (2); Mixing the mixed powder material with the flux, performing a second ball milling process to obtain a slurry after the second ball milling with a particle size X50 of 0.8 - 1.1 μm, and the composition and mass % of the flux are respectively Bi2O3: 0.01 - 0.1%, V2O5: 0.01 - 0.1%, SiO2: 0.01 - 0.1%, and ZnO: 0.01 - 0.1%, step (3); Sequentially performing granulation molding and a second sintering process on the slurry after the second ball milling to obtain the W-type hexagonal microwave ferrite material with a low linewidth, the second sintering process includes performing air sintering and then oxygen sintering at a temperature of 1150 °C - 1250 °C, and the linewidth of the W-type hexagonal microwave ferrite material with a low linewidth < 400 Oe, step (4). Providing a manufacturing method.

[0011] The manufacturing method of the low linewidth W-type hexagonal microwave ferrite material according to the present application replaces some Fe ions with the rare earth element Gd, and the chemical formula is BaGd x Ni2Fe (16~x) O 27 is limited to 0.1 < x < 0.25, and by utilizing the electromagnetic properties and compensation points of Gd and Fe, appropriate saturation magnetization, residual magnetic permeability, and linewidth are obtained. Moreover, by adding, in mass percentage, low melting point fluxes of Bi2O3: 0.01 - 0.1%, V2O5: 0.01 - 0.1%, SiO2: 0.01 - 0.1%, and ZnO: 0.01 - 0.1% respectively, the microstructure of the W-type hexagonal microwave ferrite material is improved, pores are reduced, the linewidth is reduced, and the residual magnetic permeability is increased. The manufacturing method according to the present application further adopts oxygen sintering at a temperature of 1150°C - 1250°C to reduce the pores of the W-type hexagonal microwave ferrite material, effectively reduce its linewidth, and suppress the appearance of Fe 2+ and prevent the reduction of the dielectric loss of the material.

[0012] The manufacturing method according to the present application further limits the particle size X50 of the slurry after the first ball milling treatment to 0.9 - 1.2 μm and the particle size X50 of the slurry after the second ball milling treatment to 0.8 - 1.1 μm. Its role is to make most of the particles in the single-domain state, contribute to the rolling of the magnetic moment under the action of the orientation magnetic field, obtain a good orientation effect, improve the residual magnetic permeability, and effectively reduce the porosity. Furthermore, the temperature of the first sintering treatment is 1200 - 1280°C. When the temperature is lower than 1200°C, the grain size of the crystal grains has not fully grown, the density is low, the porosity is increased, and the linewidth is increased. When the temperature is higher than 1280°C, crystal grains of excessive size appear, pores increase, the residual magnetic permeability decreases, and the linewidth is increased.

[0013] In the present application, x satisfies 0.1 < x < 0.25. For example, it may be 0.11, 0.13, 0.15, 0.18, 0.2, or 0.24, etc., but is not limited to the enumerated values, and other unenumerated values within this numerical range are equally applicable.

[0014] The particle size X50 of the slurry after the first ball milling process may be 0.9 to 1.2 μm, for example, 0.9 μm, 0.95 μm, 1 μm, 1.05 μm, 1.1 μm, or 1.2 μm, but is not limited to the listed values, and other values not listed within the numerical range also apply.

[0015] The temperature of the first sintering process is 1200 to 1280°C, and may be, for example, 1200°C, 1210°C, 1220°C, 1250°C, 1270°C, or 1280°C, but is not limited to the listed values, and other values not listed within the numerical range also apply.

[0016] The particle size X50 of the slurry after the second ball milling treatment is 0.8 to 1.1 μm, and may be, for example, 0.8 μm, 0.85 μm, 0.9 μm, 0.95 μm, 1 μm, or 1.1 μm, but is not limited to the listed values, and other values not listed within the numerical range also apply.

[0017] The composition and mass percentage of the flux are Bi2O3: 0.01-0.1%, VO5: 0.01-0.1%, SiO2: 0.01-0.1%, and ZnO: 0.01-0.1%. However, Bi2O3 may be 0.01-0.1%, e.g., 0.01%, 0.02%, 0.04%, 0.05%, 0.08%, or 0.1%, but is not limited to the recited values, and other unrecited values within the range also apply. VO5 may be 0.01-0.1%, e.g., 0.01%, 0.02%, 0.04%, 0.05%, 0.08%, or 0.1%, but is not limited to the recited values, and other unrecited values within the range also apply. SiO2 may be 0.01-0.1%, for example, 0.01%, 0.02%, 0.04%, 0.05%, 0.08%, or 0.1%, but is not limited to the recited values, and other unrecited values within the range also apply. ZnO may be 0.01-0.1%, for example, 0.01%, 0.02%, 0.04%, 0.05%, 0.08%, or 0.1%, but is not limited to the recited values, and other unrecited values within the range also apply.

[0018] The temperature of the oxygen sintering is 1150°C to 1250°C, and may be, for example, 1150°C, 1155°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 range also apply.

[0019] The linewidth of the low linewidth W-type hexagonal microwave ferrite material may be less than 400 Oe, for example, 399 Oe, 390 Oe, 380 Oe, 370 Oe, 350 Oe, or 320 Oe, but is not limited to the recited values, and other unrecited values within the range also apply.

[0020] Preferably, the rotation speed of the first ball milling process described in step (1) is 60 to 80 r / min, and may be, for example, 60 r / min, 62 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 unlisted values within the numerical range also apply.

[0021] Preferably, the time for the first ball milling treatment is 20 to 40 hours, for example, 20 hours, 23 hours, 25 hours, 30 hours, 35 hours, 38 hours, or 40 hours, but is not limited to the listed values, and other values not listed within the range also apply.

[0022] Preferably, a dispersant is added in the first ball milling process at a mass fraction of 0.01 to 0.05%, which may be, for example, 0.01%, 0.02%, 0.03%, 0.04%, or 0.05%, but is not limited to the recited values, and other unrecited values within the range also apply.

[0023] The present application does not specifically limit the type of dispersant, and any dispersant for ball milling well known to those skilled in the art can be used.

[0024] Preferably, the drying temperature in step (2) is 120 to 150°C, and may be, for example, 120°C, 125°C, 130°C, 140°C, 145°C, or 150°C, but is not limited to the listed values, and other values not listed within the range also apply.

[0025] Preferably, the drying time is 16 to 20 hours, for example, 16 hours, 16.5 hours, 17 hours, 18 hours, 19 hours, or 20 hours, but is not limited to the listed values, and other values within the range that are not listed also apply.

[0026] Preferably, the temperature rise rate of the first sintering treatment described in step (2) is 1.0 to 1.5°C / min, and may be, for example, 1.0°C / min, 1.1°C / min, 1.2°C / min, 1.3°C / min, or 1.5°C / min, but is not limited to the listed values, and other values not listed within the range also apply.

[0027] Preferably, the rotation speed of the second ball milling process described in step (3) is 60 to 80 r / min, and may be, for example, 60 r / min, 62 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 unlisted values within the numerical range also apply.

[0028] Preferably, the time for the second ball milling treatment is 15 to 24 hours, for example, 15 hours, 18 hours, 20 hours, 21 hours, 23 hours, or 24 hours, but is not limited to the listed values, and other values not listed within the range also apply.

[0029] Preferably, in the second ball milling process described in step (3), a dispersant is added at a mass fraction of 0.01 to 0.05%, which may be, for example, 0.01%, 0.02%, 0.03%, 0.04%, or 0.05%, but is not limited to the recited values, and other unrecited values within the range also apply.

[0030] Preferably, the solids content of the slurry before granulation described in step (4) is 70% or more, and may be, for example, 70%, 72%, 75%, 80%, 85%, or 90%, but is not limited to the recited values, and other values not recited within the range also apply.

[0031] Preferably, the density of the sample after granulation is 3.4 to 3.6 g / cm 3 For example, 3.4g / cm 3 , 3.41g / cm 3 , 3.45g / cm 3 , 3.5g / cm3 , 3.55g / cm 3 or 3.6 g / cm 3 However, the present invention is not limited to the listed numerical values, and other unlisted numerical values within the numerical range also apply.

[0032] Preferably, the air sintering in step (4) comprises increasing the temperature from room temperature to 120°C at a rate of 1.0°C / min, maintaining the temperature for 2 hours, and then increasing the temperature to 1000°C at a rate of 2°C / min.

[0033] Preferably, the oxygen sintering described in step (4) includes aerating oxygen at a flow rate of 30 to 50 L / min and an oxygen content of ≥ 98%, raising the temperature to the oxygen sintering temperature at a rate of 2.5°C / min, maintaining the temperature for 3 to 8 hours, lowering the temperature to 700°C at a rate of 2.5°C / min, stopping the oxygen aeration, and cooling in the furnace.

[0034] However, the flow rate may be 30 to 50 L / min, for example, 30 L / min, 35 L / min, 38 L / min, 40 L / min, 45 L / min, or 50 L / min, but is not limited to the listed values, and other unlisted values within the range also apply. The oxygen content may be 98% or higher, for example, 98%, 98.2%, 98.5%, 99%, 99.3%, or 99.5%, but is not limited to the listed values, and other unlisted values within the range also apply. The incubation time may be 3 to 8 hours, for example, 3 hours, 4 hours, 5 hours, 7 hours, or 8 hours, but is not limited to the listed values, and other unlisted values within the range also apply.

[0035] As a preferred technical solution of the present application, the manufacturing method comprises: Chemical formula BaGd x Ni2Fe (16~x) O 27(However, according to 0.1 < x < 0.25), after calculating and weighing the raw materials BaCO3, Gd2O3, Ni2O and Fe2O3, a first ball milling treatment with a rotation speed of 60 - 80 r / min is carried out for 20 - 40 h to obtain a slurry after the first ball milling with a particle size X50 of 0.9 - 1.2 μm, and the step of adding a dispersant with a mass fraction of 0.01 - 0.05% in the first ball milling treatment (1); The slurry after the first ball milling is sequentially subjected to drying at a temperature of 120 - 150 °C for 16 - 20 h and a first sintering treatment at a temperature of 1200 - 1280 °C with a heating rate of 1.0 - 1.5 °C / min to obtain a mixed powder material (2); Mix the mixed powder material and the flux, and carry out a second ball milling treatment with a rotation speed of 60 - 80 r / min for 15 - 24 h to obtain a slurry after the second ball milling with a particle size X50 of 0.8 - 1.1 μm, where the composition and mass% of the flux are respectively Bi2O3: 0.01 - 0.1%, V2O5: 0.01 - 0.1%, SiO2: 0.01 - 0.1% and ZnO: 0.01 - 0.1%, and the step of adding a dispersant with a mass fraction of 0.01 - 0.05% in the second ball milling treatment (3); The slurry after the second ball milling is sequentially subjected to granulation molding and a second sintering treatment to obtain the low linewidth W-type hexagonal microwave ferrite material, where the linewidth of the low linewidth W-type hexagonal microwave ferrite material < 400 Oe; The solid content of the slurry before granulation molding ≥ 70%, and the density of the sample after granulation molding is 3.4 - 3.6 g / cm 3 Yes; The second sintering step includes air sintering followed by oxygen sintering, and the air sintering includes increasing the temperature from room temperature to 120°C at a rate of 1.0°C / min, maintaining the temperature for 2 hours, and then increasing the temperature to 1000°C at a rate of 2°C / min. The oxygen sintering includes aerating oxygen at a flow rate of 30-50 L / min and an oxygen content of ≥ 98%, increasing the temperature to a sintering temperature of 1150°C-1250°C at a rate of 2.5°C / min, maintaining the temperature for 3-8 hours, and then decreasing the temperature to 700°C at a rate of 2.5°C / min, and stopping the oxygen aeration and cooling in a furnace. (4) [Effects of the Invention]

[0036] Compared with the related art, the embodiments of the present application have at least the following beneficial effects:

[0037] The method for producing a low linewidth W-type hexagonal microwave ferrite material according to the present invention is a stable process with good reproducibility, and the obtained W-type hexagonal microwave ferrite material has a linewidth of <400 Oe, a saturation magnetization of 3700 to 3900 Gs, a remanence of >0.9, and a density of >5.0 g / cm. 3 and there is a prospect of widespread adoption.

[0038] Other aspects may be understood upon reading and understanding the detailed description. DETAILED DESCRIPTION OF THE INVENTION

[0039] In order to facilitate understanding of the present application, the present application provides the following examples, which should be understood by those skilled in the art as being merely for the purpose of understanding the present application and should not be considered as specific limitations of the present application.

[0040] The present application will be described in more detail below. The following examples are merely illustrative of the present application and do not represent or limit the scope of the claims of the present application, and the scope of protection of the present application is based on the claims.

[0041] Example 1 This embodiment provides a method for manufacturing a low linewidth W-type hexagonal microwave ferrite material, which includes the following steps:

[0042] (1') Chemical formula BaGd x Ni2Fe (16~x) O 27 The raw materials BaCO3, Gd2O3, Ni2O, and Fe2O3 were calculated and weighed according to (where x = 0.2), where the purity of BaCO3 was 99.65%, the purity of Gd2O3 was 99.5%, the purity of Ni2O was 99.5%, and the purity of Fe2O3 was 99.5%.

[0043] (2') The raw materials were placed in a ball mill pot and mixed using a ball mill. The raw materials: deionized water: zirconia balls (large: small) were charged in a weight ratio of 1000:1000:(4000:1000). A first ball milling process was carried out at a rotation speed of 70 r / min for 24 hours. A dispersant was added at a mass fraction of 0.02% during the first ball milling process. The particle size X50 of the slurry after the first ball milling process was 0.9 to 1.2 μm.

[0044] (3') The slurry after the first ball milling process was placed in an oven and dried at a drying temperature of 140°C for 18 hours. The dried powder was then sieved through a 60-mesh sieve and placed in an air sintering furnace for the first sintering process for 5 hours. The temperature was then raised to 1250°C at a rate of 1.5°C / min to obtain a mixed powder.

[0045] (4') The mixed powder material, flux, and dispersant with a mass fraction of 0.02% were mixed, then placed in a ball mill pot and mixed using a horizontal ball mill. The weight ratio of materials: deionized water: zirconia balls (large: small) was 1000:1000:(4000:1000). A second ball milling process was performed at a rotation speed of 70 r / min for 16 hours. The particle size X50 of the slurry after the second ball milling process was 0.8 to 1.1 μm, and the composition and mass% of the flux were Bi2O3: 0.06%, VO5: 0.06%, SiO2: 0.06%, and ZnO: 0.06%, respectively.

[0046] (5') After the second ball milling treatment, excess water was filtered off from the slurry using a filter cloth so that the solid content of the slurry was 70% or more.

[0047] (6') The treated slurry was subjected to orientation molding, and the resulting sample size was Z42*8, and the molding density was 3.4 g / cm 3 It was.

[0048] (7') The sample was subjected to air sintering and then oxygen sintering. The air sintering involved raising the temperature from room temperature to 120°C at a rate of 1.0°C / min, maintaining the temperature for 2 hours, and then raising the temperature to 1000°C at a rate of 2°C / min. The oxygen sintering involved passing oxygen with a flow rate of 40 L / min and an oxygen content of 98%, raising the temperature to a sintering temperature of 1180°C at a rate of 2.5°C / min, maintaining the temperature for 6 hours, then lowering the temperature to 700°C at a rate of 2.5°C / min, stopping the oxygen passage, and cooling in a furnace. The low-linewidth W-type hexagonal microwave ferrite material was obtained.

[0049] Example 2 This example provides a method for preparing a low linewidth W-type hexagonal microwave ferrite material, and the preparation method is the same as that of Example 1, except that in step (1'), x=0.18.

[0050] Comparative Example 1 This comparative example provides a method for manufacturing a low linewidth W-type hexagonal microwave ferrite material, and the manufacturing method is the same as that of Example 1, except that x=0 in step (1′).

[0051] Comparative Example 2 This comparative example provides a method for manufacturing a low linewidth W-type hexagonal microwave ferrite material, and the manufacturing method is the same as that of Example 1, except that in step (1'), x=0.3.

[0052] Comparative Example 3 This comparative example provides a method for manufacturing a low-linewidth W-type hexagonal microwave ferrite material, and the manufacturing method is the same as that of Example 1, except that the temperature of the first sintering process in step (3') is 1150°C.

[0053] Comparative Example 4 This comparative example provides a method for manufacturing a low-linewidth W-type hexagonal microwave ferrite material, and the manufacturing method is the same as that of Example 1, except that the temperature of the first sintering process in step (3') is 1300°C.

[0054] Comparative Example 5 This comparative example provides a method for manufacturing a low-linewidth W-type hexagonal microwave ferrite material, and the manufacturing method is the same as that of Example 1, except that in step (4'), the composition and mass percentage of the flux are Bi2O3: 0.12%, V2O5: 0.12%, SiO2: 0.12% and ZnO: 0.06%, respectively.

[0055] Comparative Example 6 This comparative example provides a method for preparing a low linewidth W-type hexagonal microwave ferrite material, and the method is the same as that of Example 1, except that no flux is added in step (4').

[0056] Comparative Example 7 This comparative example provides a method for manufacturing a low-linewidth W-type hexagonal microwave ferrite material, and the manufacturing method is the same as that of Example 1, except that in step (4'), the composition and mass% of the flux are V2O5: 0.12%, SiO2: 0.12%, and ZnO: 0.06%, respectively.

[0057] Comparative Example 8 This comparative example provides a method for manufacturing a low-linewidth W-type hexagonal microwave ferrite material, and the manufacturing method is the same as that of Example 1, except that in step (2'), the first ball milling treatment time is h and the particle size X50 of the obtained slurry after the first ball milling treatment is μm.

[0058] Comparative Example 9 This comparative example provides a method for manufacturing a low-linewidth W-type hexagonal microwave ferrite material, which is the same as Example 1, except that in step (4'), the second ball milling treatment time is h and the particle size X50 of the obtained slurry after the second ball milling treatment is μm.

[0059] Comparative Example 10 This comparative example provides a method for preparing a low linewidth W-type hexagonal microwave ferrite material, and the method is the same as that in Example 1, except that the oxygen sintering temperature in step (7') is 1100°C.

[0060] Comparative Example 11 This comparative example provides a method for manufacturing a low linewidth W-type hexagonal microwave ferrite material, and the manufacturing method is the same as that of Example 1, except that the oxygen sintering temperature in step (7') is 1280°C.

[0061] Comparative Example 12 This comparative example provides a method for manufacturing a low-linewidth W-type hexagonal microwave ferrite material, which is the same as Example 1, except that in step (7'), the temperature is lowered directly in air without oxygen sintering.

[0062] The W-type hexagonal microwave ferrite materials obtained in the above examples and comparative examples were processed into spheres with a diameter of 2.5 mm, and the saturation magnetization thereof was measured.

[0063] The W-type hexagonal microwave ferrite materials obtained in the above examples and comparative examples were processed into Z38*6 samples, and their remanence was measured.

[0064] The W-type hexagonal microwave ferrite materials obtained in the above examples and comparative examples were processed into spheres with a diameter of 1 mm, and the line widths thereof were measured.

[0065] The density of the W-type hexagonal microwave ferrite materials obtained in the above examples and comparative examples was measured using the water substitution method, and the test results are shown in Table 1.

[0066] [Table 1]

[0067] As can be seen from Table 1, the W-type hexagonal microwave ferrite material obtained by the manufacturing method of the present invention has a linewidth of <400 Oe, a saturation magnetization of 3700 to 3900 Gs, a remanence of >0.9, and a density of >5.0 g / cm 3 and there is a prospect of widespread adoption.

[0068] If Gd is not added to the raw materials or if the Gd content is too high, the resulting W-type hexagonal microwave ferrite material has a high linewidth. If the temperature of the first sintering process is low, the linewidth is high, although other properties are equivalent to those of Example 1. If no flux is added, or the composition and content of each substance in the flux are not within the ranges of the present application, the W-type hexagonal microwave ferrite material has a high linewidth and a low remanence. If the particle sizes of the slurry after the first ball milling process and the slurry after the second ball milling process are large, the W-type hexagonal microwave ferrite material has a high linewidth, a low remanence, and a low density. If the oxygen sintering temperature is not within the range of the present application, the W-type hexagonal microwave ferrite material has a high linewidth and a low remanence.

[0069] In summary, the manufacturing method of the low linewidth W-type hexagonal microwave ferrite material according to the present invention is a stable process with good reproducibility, and is expected to be widely used.

[0070] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto, and the applicant declares that it should be understood that any modifications or replacements that a person skilled in the art can easily conceive within the technical scope disclosed in the present application are all included in the scope of protection and disclosure of the present application.

Claims

1. 1. A method for producing a low linewidth W-type hexagonal microwave ferrite material, comprising: Chemical formula BaGd ｘ Ni ２ Fe （１６～ｘ） O ２７ (where 0.1<x<0.25) depending on the raw material BaCO ３ , Gd ２ O ３ , Ni ２ O and Fe ２ O ３ (1) calculating and weighing the slurry, and then performing a first ball milling process to obtain a slurry after the first ball milling having a particle size X50 of 0.9 to 1.2 μm; (2) drying the slurry after the first ball milling and then subjecting it to a first sintering treatment at a temperature of 1200 to 1280°C to obtain a mixed powder material; A step of mixing the mixed powder material with a flux and performing a second ball milling process to obtain a slurry after the second ball milling having a particle size X50 of 0.8 to 1.1 μm, wherein the composition and mass % of the flux are each Bi ２ O ３ :0.01~0.1%, V ２ O ５ :0.01~0.1%, SiO ２ Step (3) in which: 0.01 to 0.1% and ZnO: 0.01 to 0.1%; (4) sequentially subjecting the slurry after the second ball milling to granulation and second sintering treatment to obtain the low linewidth W-type hexagonal microwave ferrite material, wherein the second sintering treatment includes air sintering followed by oxygen sintering at a temperature of 1150°C to 1250°C, and the low linewidth W-type hexagonal microwave ferrite material has a linewidth of <400 Oe; Manufacturing method.

2. The rotation speed of the first ball milling treatment described in step (1) is 60 to 80 r / min. The method of claim 1.

3. The duration of the first ball milling treatment is 20 to 40 hours; The method of claim 2.

4. adding a dispersant at a mass fraction of 0.01 to 0.05% in the first ball milling treatment; The method of claim 3.

5. The drying temperature in step (2) is 120 to 150°C; The drying time is 16 to 20 hours. The method of claim 1.

6. The temperature increase rate of the first sintering treatment described in step (2) is 1.0 to 1.5 ° C. / min. The method of claim 1.

7. The rotation speed of the second ball milling treatment described in step (3) is 60 to 80 r / min; The second ball milling treatment is carried out for 15 to 24 hours. The method of claim 1.

8. In the second ball milling treatment described in step (3), a dispersant is added at a mass fraction of 0.01 to 0.05%. The method of claim 1.

9. The solid content of the slurry before granulation described in step (4) is ≥ 70%; The density of the sample after granulation is 3.4 to 3.6 g / cm ３ That is, The method of claim 1.

10. The air sintering described in step (4) includes increasing the temperature from room temperature to 120°C at a rate of 1.0°C / min, maintaining the temperature for 2 hours, and then increasing the temperature to 1000°C at a rate of 2°C / min. The method of claim 1.

11. The oxygen sintering process in step (4) includes: passing oxygen at a flow rate of 30-50 L / min and an oxygen content of ≥ 98%, raising the temperature to the oxygen sintering temperature at a rate of 2.5 ° C / min, keeping the temperature for 3-8 hours, then lowering the temperature to 700 ° C at a rate of 2.5 ° C / min, stopping the oxygen passage, and cooling in the furnace; The method of claim 1.

12. Chemical formula BaGd ｘ Ni ２ Fe （１６～ｘ） O ２７ (where 0.1<x<0.25) depending on the raw material BaCO ３ , Gd ２ O ３ , Ni ２ O and Fe ２ O ３ After calculating and weighing, a first ball milling process is performed at a rotation speed of 60 to 80 r / min for 20 to 40 hours to obtain a slurry after the first ball milling having a particle size X50 of 0.9 to 1.2 μm, and a step (1) of adding a dispersant at a mass fraction of 0.01 to 0.05% in the first ball milling process; Step (2) of sequentially subjecting the slurry after the first ball milling to drying at a temperature of 120 to 150 ° C. for 16 to 20 hours and a first sintering treatment at a temperature of 1200 to 1280 ° C. and a temperature increase rate of 1.0 to 1.5 ° C. / min to obtain a mixed powder material; The mixed powder material and flux are mixed, and a second ball milling process is performed at a rotation speed of 60 to 80 r / min for 15 to 24 hours to obtain a slurry after the second ball milling having a particle size X50 of 0.8 to 1.1 μm, wherein the composition and mass % of the flux are each Bi ２ O ３ :0.01~0.1%, V ２ O ５ :0.01~0.1%, SiO ２ : 0.01 to 0.1% and ZnO: 0.01 to 0.1%, and in the second ball milling process, a dispersant is added at a mass fraction of 0.01 to 0.05%; (4) sequentially performing granulation molding and second sintering treatment on the slurry after the second ball milling to obtain the low linewidth W-type hexagonal microwave ferrite material, wherein the low linewidth W-type hexagonal microwave ferrite material has a linewidth of <400 Oe; The solid content of the slurry before granulation is ≧70%, and the density of the sample after granulation is 3.4 to 3.6 g / cm ３ and the second sintering step includes air sintering followed by oxygen sintering, the air sintering includes increasing the temperature from room temperature to 120°C at a rate of 1.0°C / min, maintaining the temperature for 2 hours, and then increasing the temperature to 1000°C at a rate of 2°C / min; the oxygen sintering includes increasing the temperature to a sintering temperature of 1150°C to 1250°C at a rate of 2.5°C / min while supplying oxygen with a flow rate of 30 to 50 L / min and an oxygen content of ≥ 98%, maintaining the temperature for 3 to 8 hours, and then decreasing the temperature to 700°C at a rate of 2.5°C / min, and then stopping the supply of oxygen and cooling in a furnace; The method of claim 1.

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