CN116621571B - Microwave ferrite material, preparation method and dielectric constant adjusting method - Google Patents
Microwave ferrite material, preparation method and dielectric constant adjusting method Download PDFInfo
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- CN116621571B CN116621571B CN202310389828.XA CN202310389828A CN116621571B CN 116621571 B CN116621571 B CN 116621571B CN 202310389828 A CN202310389828 A CN 202310389828A CN 116621571 B CN116621571 B CN 116621571B
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- 238000000034 method Methods 0.000 title claims abstract description 97
- 239000000463 material Substances 0.000 title claims abstract description 78
- 229910000859 α-Fe Inorganic materials 0.000 title claims abstract description 38
- 238000002360 preparation method Methods 0.000 title claims abstract description 12
- 239000000126 substance Substances 0.000 claims abstract description 8
- 238000005245 sintering Methods 0.000 claims description 155
- 238000000498 ball milling Methods 0.000 claims description 64
- 238000010438 heat treatment Methods 0.000 claims description 48
- 238000001816 cooling Methods 0.000 claims description 24
- 238000005303 weighing Methods 0.000 claims description 13
- 239000002002 slurry Substances 0.000 claims description 11
- 238000001035 drying Methods 0.000 claims description 10
- 239000002994 raw material Substances 0.000 claims description 10
- 239000000843 powder Substances 0.000 claims description 9
- 239000008187 granular material Substances 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- 238000003825 pressing Methods 0.000 claims description 7
- 239000000853 adhesive Substances 0.000 claims description 6
- 230000001070 adhesive effect Effects 0.000 claims description 6
- 238000013461 design Methods 0.000 claims description 5
- 238000009472 formulation Methods 0.000 claims description 3
- 238000009818 secondary granulation Methods 0.000 claims description 3
- 238000001694 spray drying Methods 0.000 claims description 3
- 238000007873 sieving Methods 0.000 claims description 2
- 239000011230 binding agent Substances 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 claims 1
- 230000005350 ferromagnetic resonance Effects 0.000 abstract description 9
- 239000000696 magnetic material Substances 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 22
- 229910015902 Bi 2 O 3 Inorganic materials 0.000 description 15
- 238000000227 grinding Methods 0.000 description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 11
- 239000011572 manganese Substances 0.000 description 11
- 239000002223 garnet Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical group O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 238000009770 conventional sintering Methods 0.000 description 3
- 239000008367 deionised water Substances 0.000 description 3
- 229910021641 deionized water Inorganic materials 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 230000010354 integration Effects 0.000 description 3
- 229910001437 manganese ion Inorganic materials 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 238000010923 batch production Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005469 granulation Methods 0.000 description 2
- 230000003179 granulation Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- WAEMQWOKJMHJLA-UHFFFAOYSA-N Manganese(2+) Chemical compound [Mn+2] WAEMQWOKJMHJLA-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 125000005842 heteroatom Chemical group 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- MTRJKZUDDJZTLA-UHFFFAOYSA-N iron yttrium Chemical compound [Fe].[Y] MTRJKZUDDJZTLA-UHFFFAOYSA-N 0.000 description 1
- 230000005291 magnetic effect Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
- C04B35/2608—Compositions containing one or more ferrites of the group comprising manganese, zinc, nickel, copper or cobalt and one or more ferrites of the group comprising rare earth metals, alkali metals, alkaline earth metals or lead
- C04B35/2633—Compositions containing one or more ferrites of the group comprising manganese, zinc, nickel, copper or cobalt and one or more ferrites of the group comprising rare earth metals, alkali metals, alkaline earth metals or lead containing barium, strontium or calcium
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
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- C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
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- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
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Abstract
The invention relates to the field of magnetic materials, in particular to a microwave ferrite material, a preparation method and a dielectric constant adjusting method, wherein the microwave ferrite material comprises the following chemical formula: bi (Bi) a Y 3‑a‑b‑e Ca b+ e Zr b Mn c Cr d Hf e Fe 5‑b‑c‑d‑e O 12 Wherein a is more than or equal to 1.25 and less than or equal to 1.5,0.475, b is more than or equal to 0.6,0 and less than or equal to c is more than or equal to 0.1, d is more than or equal to 0 and less than or equal to 0.05, and e is more than or equal to 0 and less than or equal to 0.05. The microwave ferrite material has the characteristics of high dielectric constant, narrow ferromagnetic resonance line width and low dielectric loss.
Description
Technical Field
The invention relates to the field of magnetic materials, in particular to a high-dielectric-constant microwave ferrite material for microwave communication.
Background
Microwave ferrites have wide applications in 5G applications, aerospace, electronic countermeasure and medical applications. The core of the microwave ferrite device is the microwave ferrite material, and the microwave ferrite material is applied to devices such as a circulator, an isolator, a phase shifter and the like, and plays roles in switching, amplifying, phase shifting and the like in a system. Yttrium Iron Garnet (YIG) has been widely studied for its unique application potential due to its excellent gyromagnetic properties and extremely low ferromagnetic resonance linewidth values. YIG has excellent properties of low ferroresonance linewidth, high resistivity, low dielectric loss, etc., compared to all other ferrite materials in the radio frequency and microwave frequency bands.
The dielectric constant of the conventional microwave ferrite is between 12 and 16, the size of the device is larger when the low-frequency circulator isolator is designed, and the requirements of miniaturization and integration cannot be met. If the dielectric constant of ferrite is increased to more than 25, the size of the isolator circulator can be reduced by more than 25%, so that the requirements of miniaturization and integration are met.
In the past, research into microwave ferrites has focused on reducing the microwave magnetic loss of materials, while less research has been conducted on the dielectric constant of microwave ferrite materials. In recent years, with the development of 5G communication, device designers are continually raising the demand for high dielectric constant materials, particularly small linewidth materials. Garnet ferrite materials with high dielectric constants are thus one of the hot spots in the field of microwave ferrite research.
According to the prior reports, such as the patent application of Chinese patent publication No. CN102976740A, by adding Bi 3 + 、Ti 4+ Increase dielectric constant, bi 3+ Substituted dodecahedral position Y 3+ ，Ti 4+ Substituted octahedral position Fe 3+ However, in order to meet the requirement of small line width, the dielectric constant of the material is not high, and is generally between 13.5 and 15. For another patent application, chinese patent CN111285673A, the chemical formula is Bi 1.25 Ca 0.25+2x Y 1.5-2x Zr 0.25 Al x Mn y Fe 4.75-x-y It can be derived from charge conservation calculation that octahedral substituted Fe 3+ The manganese ion of the ion is +7 valent, and the inventors of the present application have proved through a large number of experiments that Mn is used 3 O 4 In the process of preparing garnet ferrite from raw materials, manganese ions are difficult to oxidize to +7, the prepared garnet ferrite material contains a large amount of hetero-phases, the ferromagnetic resonance line width of the material can be increased sharply, and the practical use requirement cannot be met.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a microwave ferrite material which has the characteristics of high dielectric constant and narrow ferromagnetic resonance linewidth so as to meet the urgent demands of miniaturization and integration of complete systems such as communication base stations and the like.
The technical scheme adopted by the invention for solving the technical problems is that the microwave ferrite material comprises the following chemical formula:
Bi a Y 3-a-b-e Ca b+e Zr b Mn c Cr d Hf e Fe 5-b-c-d-e O 12
wherein a is more than or equal to 1.25 and less than or equal to 1.5,0.475, b is more than or equal to 0.6,0 and less than or equal to c is more than or equal to 0.1, d is more than or equal to 0 and less than or equal to 0.05, and e is more than or equal to 0 and less than or equal to 0.05.
The invention also provides a preparation method of the microwave ferrite material, which comprises the following steps:
(1) The formula design is carried out according to the following composition chemical formula:
Bi a Y 3-a-b-e Ca b+e Zr b Mn c Cr d Hf e Fe 5-b-c-d-e O 12 ，
wherein a is more than or equal to 1.25 and less than or equal to 1.5,0.475, b is more than or equal to 0.6,0 and less than or equal to c is more than or equal to 0.1, d is more than or equal to 0 and less than or equal to 0.05, and e is more than or equal to 0 and less than or equal to 0.05;
(2) Proportioning and weighing: in the form of oxide Y 2 O 3 、CaCO 3 、Fe 2 O 3 、Mn 3 O 4 、HfO 2 、Cr 2 O 5 、ZrO 2 And as raw materials, weighing according to the formula proportion; wherein Bi is 2 O 3 Weighing 20% -30% of the materials to obtain Bi for secondary ball milling 2 O 3 The rest part is used as the Bi of the primary ball milling 2 O 3 Material preparation;
(3) Ball milling for the first time: ball milling Bi once 2 O 3 The materials and the weighing materials of other components in the step (2) are put into a ball milling tank, and ball milling medium is added for ball milling;
(4) Presintering: drying the primary ball milling slurry and presintering;
(5) Secondary ball milling: pre-sintered powder and Bi are ball milled twice 2 O 3 Adding the materials into a ball milling medium together for secondary ball milling for 6-24 hours;
(6) Granulating: drying the slurry subjected to secondary ball milling, and adding 7-8wt% of adhesive based on the dried mass of the slurry for granulating to obtain granules;
(7) And (3) forming: pressing the granulated ferrite powder to obtain a green body of the material;
(8) Sintering: and placing the formed material green body into a sintering furnace for sintering.
Further, in the step (8), when the temperature is raised to the sintering temperature, the temperature is quickly raised to 50-100 ℃, the temperature is kept for 20-30 min, the temperature is quickly lowered to the sintering temperature, and the temperature is kept for 30-50 h; the sintering temperature is 860-880 ℃.
In the step (7), the pressure is 200-300 MPa.
In the step (6), the adhesive is PVA solution, and granulation is carried out by a spray drying tower; and (3) sieving the powder with a 40-mesh sieve, and performing secondary granulation on the cake under the pressure of 200MPa, wherein the granularity is less than 1.2 microns.
In the step (4) and the step (8), bi is added into a sintering furnace 2 O 3 Is a sintering boat of (2).
The invention also provides a method for adjusting the dielectric constant of the microwave ferrite material, which is used for adjusting the dielectric constant of the microwave ferrite material prepared by adjusting the numerical value of a in the step (1) of the preparation method.
The microwave ferrite material has the characteristics of high dielectric constant, narrow ferromagnetic resonance line width and low dielectric loss, and the dielectric constant epsilon: 28-epsilon-32, ferromagnetic resonance line width delta H-40 Oe and dielectric loss tg delta-2 x 10 -4 . By adopting the preparation method of the invention, bi is added in a standing way in the presintering process 2 O 3 To suppress Bi in the presintered material 2 O 3 Is volatilized. By adopting a sintering process with rapid temperature rise and drop in the sintering process, the activity is reduced, and the sintering temperature zone is widened while abnormal growth of crystal grains is avoided. In addition, the invention has lower cost and effectively reduces the sintering temperature.
Drawings
FIG. 1 is a graph showing the variation of dielectric constant with sintering temperature of samples prepared by a rapid soak process and a conventional sintering process, respectively.
FIG. 2 is a graph showing the saturation magnetization as a function of sintering temperature for samples prepared by the rapid soak process and the conventional sintering process, respectively.
Fig. 3 is a graph showing the variation of the ferromagnetic resonance linewidth with sintering temperature for a sample prepared by a rapid soak process and a conventional sintering process, respectively.
FIG. 4 is a plot of dielectric constant as a function of sintering temperature for samples prepared using a step-wise batch process and a conventional batch process, respectively.
FIG. 5 is a plot of saturation magnetization as a function of sintering temperature for samples prepared using a step-wise dosing process and a conventional dosing process, respectively.
Fig. 6 is a plot of the ferromagnetic resonance linewidth as a function of sintering temperature for samples prepared using a step-wise dispensing process and a conventional dispensing process, respectively.
Detailed Description
The invention provides a high dielectric garnet ferrite material which has the characteristics of high dielectric property, small line width and low dielectric loss at lower cost.
The invention reduces the activity by adopting a sintering process with rapid temperature rise and drop in the sintering process, and widens the sintering temperature zone while avoiding abnormal growth of crystal grains.
In particular, bi was found through a large number of experiments and analyses 2 O 3 The volatilization is concentrated in the presintering stage, so that in the batching stage, bi is adopted from 2 O 3 Taking out 20% -30% of the weighed materials, adding the taken-out part and the presintered materials together in a secondary grinding stage, and inhibiting Bi 2 O 3 And the sintering temperature is greatly reduced while volatilizing.
Bi is adopted in the invention 2 O 3 After weighing, the material is divided into two parts, wherein one part is added in a primary ball milling step, and the other part is added in a secondary ball milling step, and the mode is called step-by-step batching.
The invention provides a low-linewidth low-loss microwave garnet material with adjustable dielectric constant, which comprises the following chemical formula: bi (Bi) a Y 3-a-b-e Ca b+e Zr b Mn c Cr d Hf e Fe 5-b-c-d-e O 12
Wherein a is more than or equal to 1.25 and less than or equal to 1.5,0.475, b is more than or equal to 0.6,0 and less than or equal to c is more than or equal to 0.1, d is more than or equal to 0 and less than or equal to 0.05, and e is more than or equal to 0 and less than or equal to 0.05.
Subscript values represent mole fractions.
Proved by a plurality of experiments, when Mn is used 3 O 4 In the process of preparing garnet ferrite from raw materials, manganese ions are difficult to oxidize to +7, the prepared garnet ferrite material contains more hetero phases, the ferromagnetic resonance line width is rapidly increased and cannot meet the actual use requirement, so that Mn ions are +3 in the invention, the positive molecular formula is met, and simultaneously, the dielectric constant is improved and the line width is reduced, thereby meeting the actual requirement.
The preparation method of the ferrite material comprises the following steps:
(1) The formula design is carried out according to the following composition chemical formula:
Bi a Y 3-a-b-e Ca b+e Zr b Mn c Cr d Hf e Fe 5-b-c-d-e O 12 wherein a is more than or equal to 1.25 and less than or equal to 1.5,0.475 and b is more than or equal to 0.6,
0≤c≤0.1，0≤d≤0.05，0≤e≤0.05。
(2) According to the raw material proportionWeighing: oxide Y to be referred to in the formulation 2 O 3 、CaCO 3 、Fe 2 O 3 、Mn 3 O 4 、HfO 2 、Cr 2 O 5 、ZrO 2 Raw materials are weighed according to the proportion, bi 2 O 3 The amount is reduced by 20 to 30 percent in the batching stage;
(3) Ball milling for the first time: placing the weighed materials into a ball milling tank, and adding a ball milling medium for ball milling;
(4) Presintering: drying the primary ball milling slurry and presintering;
(5) Secondary ball milling: mixing the presintered powder with Bi reduced in the step (2) 2 O 3 Adding a ball milling medium together for secondary ball milling for 6-24 hours;
(6) Granulating: drying the slurry subjected to secondary ball milling, adding 7-8wt% of adhesive, and granulating to obtain granules;
(7) And (3) forming: placing the granulated ferrite powder into a die for pressing, wherein the pressure is 200-300 MPa, and obtaining a green body of the material;
(8) Sintering: placing the formed material green body into a sintering furnace for sintering; and when the temperature is raised to the sintering temperature, the temperature is quickly raised to 50-100 ℃, the temperature is kept for 20-30 min, the temperature is quickly lowered to the sintering temperature, and the temperature is kept for 30-50 h.
Preferably: in the step (1), the value of a is adjusted to adjust the dielectric constant of the material.
Preferably: in the step (2), raw materials with small and uniform granularity are selected, so that the presintering is more sufficient.
Preferably: in the steps (3) and (5), the ball: and (3) material: the mass ratio of the ball milling medium is as follows: (3-4): 1: (1.0-1.5), wherein the inner wall of the ball milling tank is made of nonferrous materials; the ball milling medium is deionized water, distilled water or absolute alcohol; the ball is made of nonferrous materials, and the ball milling time is 6-24 hours according to the material proportion and the rotation speed.
Preferably: in the step (4), bi is added in the presintering process 2 O 3 To suppress Bi in the presintered material 2 O 3 Is volatilized.
Preferably: in the step (5), the rotating speed of the ball milling tank is 200-300 rpm according to different material proportions.
Preferably: in the step (6), the adhesive is PVA solution, and granulation is carried out by a spray drying tower; the powder is sieved by a 40-mesh sieve and pressed into cakes under the pressure of 200MPa for secondary granulation, so that the powder is more uniform, and the granularity is less than 1.2 microns.
Preferably: in the step (8), a tube furnace is selected as the sintering furnace, and Bi is added in a standing manner in the sintering process 2 O 3 To suppress Bi in the sintered body 2 O 3 Volatilizing; the sintering temperature is 870 ℃, and the heat preservation time is 30 hours.
Embodiment one: the preparation method of the microwave ferrite material comprises the following steps:
(1) The formula design is carried out according to the following composition chemical formula:
Bi a Y 3-a-b-e Ca b+e Zr b Mn c Cr d Hf e Fe 5-b-c-d-e O 12
where a=1.45, b=0.55, c=0.025, d=0.007, e=0.006;
(2) Weighing the raw materials according to the proportion: according to step (1) the oxide Y involved in the formulation 2 O 3 、HfO 2 、CaCO 3 、Fe 2 O 3 、ZrO 2 The raw materials are weighed according to the proportion, bi 2 O 3 The amount is reduced by 20-30% in the batching stage;
(3) Ball milling for the first time: and (3) placing the materials weighed in the step (2) into a polyurethane ball milling tank, and adding deionized water for ball milling. Ball: and (3) material: the mass ratio of the ball milling medium is as follows: 4:1:1.5; ball milling time is 6 hours;
(4) Presintering: drying the primary ball milling slurry obtained in the step (3) and presintering, wherein the presintering temperature is 840 ℃, and adding Bi in a standing manner during presintering 2 O 3 To suppress Bi in the presintered material 2 O 3 Is volatilized;
(5) Secondary ball milling: mixing the material obtained after the burning in the step (4) with the Bi reduced in the step (2) 2 O 3 Put into polyurethane ball milling tank togetherAnd adding deionized water for ball milling. Ball milling medium: and (3) material: the mass ratio of the ball is as follows: 4:1:1.5; performing secondary ball milling for 6 hours;
(6) Granulating: drying the slurry subjected to secondary ball milling, adding 10wt% of PVA solution, and granulating to obtain granules;
(7) And (3) forming: placing the granulated granules into a die for pressing, wherein the pressure is 200MPa, and obtaining a green body of the material;
(8) Sintering: placing the formed material green body into a sintering furnace for sintering; after the temperature is raised to the sintering temperature, the temperature is quickly raised to 50-100 ℃, the temperature is kept for 20-30 min, the temperature is quickly lowered to the sintering temperature, and the temperature is kept for 30-50 h; the sintering temperature is 810-950 ℃.
Based on the first embodiment, different parameters are adopted as the following examples.
Example 1: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 810 ℃;
example 2: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 820 ℃;
example 3: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 830 ℃;
example 4: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; by usingThe rapid temperature rise and reduction sintering process comprises the steps of rapidly heating to 60 ℃ after heating to a sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 840 ℃;
example 5: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 850 ℃;
example 6: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 860 ℃;
example 7: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 870 ℃;
comparative example 1: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a traditional sintering process, and preserving heat for 36 hours; the sintering temperature is 810 ℃;
comparative example 2: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a traditional sintering process, and preserving heat for 36 hours; the sintering temperature is 820 ℃;
comparative example 3: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a traditional sintering process, and preserving heat for 36 hours; the sintering temperature is 830 ℃;
comparative example 4: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a traditional sintering process, and preserving heat for 36 hours; the sintering temperature is 840 ℃;
comparative example 5: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a traditional sintering process, and preserving heat for 36 hours; the sintering temperature is 850 ℃;
comparative example 6: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a traditional sintering process, and preserving heat for 36 hours; the sintering temperature is 860 ℃;
comparative example 7: adopts a step-by-step batching process, bi 2 O 3 15% reduction in dosing stage, reduced Bi 2 O 3 Adding in the secondary grinding process; adopting a traditional sintering process, and preserving heat for 36 hours; the sintering temperature is 870 ℃;
comparative example 8: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 810 ℃;
comparative example 9: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 820 ℃;
comparative example 10: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 830 ℃;
comparative example 11: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 840 ℃;
comparative example 12: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 850 ℃;
comparative example 13: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 860 ℃;
comparative example 14: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 870 ℃;
comparative example 15: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 880 ℃;
comparative example 16: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 890 ℃;
comparative example 17: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 900 ℃;
comparative example 18: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 910 ℃;
comparative example 19: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; sintering temperature is 920 ℃;
comparative example 20: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 930 ℃;
comparative example 21: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; sintering temperature is 940 ℃;
comparative example 22: adopting a traditional batching process; adopting a rapid temperature-rise and temperature-reduction sintering process, rapidly heating to 60 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 25min, and preserving heat for 36h; the sintering temperature is 950 ℃;
the corresponding diagrams in table 1 are fig. 1, 2 and 3. The rapid temperature rise and fall process can effectively reduce the sensitivity of the material to sintering temperature, thereby widening the temperature zone and improving the sintering stability.
The corresponding graphs of table 2 are fig. 4, 5 and 6. The step-by-step batching process can greatly reduce the sintering temperature, thereby reducing the cost.
TABLE 1
TABLE 2
Claims (6)
1. The microwave ferrite material is characterized by being prepared by a method comprising the following steps:
(1) The formula design is as follows: the formulation was designed according to the following compositional formula:
Bi a Y 3-a-b-e Ca b+e Zr b Mn c Cr d Hf e Fe 5-b-c-d-e O 12 ，
wherein a is more than or equal to 1.25 and less than or equal to 1.5,0.475, b is more than or equal to 0.6, c is more than or equal to 0.1, d is more than or equal to 0.05, and e is more than or equal to 0.05;
(2) Proportioning and weighing: in Y form 2 O 3 、CaCO 3 、Fe 2 O 3 、Mn 3 O 4 、HfO 2 、Cr 2 O 5 、ZrO 2 And Bi (Bi) 2 O 3 As raw materials, weighing according to the formula proportion; wherein Bi is 2 O 3 Weighing and separating 20% -30% of the materials to obtain Bi for secondary ball milling 2 O 3 The rest part is used as the Bi of the primary ball milling 2 O 3 Material preparation;
(3) Ball milling for the first time: ball milling Bi once 2 O 3 The materials and the weighing materials of other components in the step (2) are put into a ball milling tank, and ball milling medium is added for ball milling;
(4) Presintering: drying the primary ball milling slurry and presintering;
(5) Secondary ball milling: pre-sintered powder and Bi are ball milled twice 2 O 3 Adding the materials into a ball milling medium together for secondary ball milling for 6-24 hours;
(6) Granulating: drying the slurry subjected to secondary ball milling, adding 7-8wt% of adhesive, and granulating to obtain granules;
(7) And (3) forming: pressing the granules obtained in the step (6) to obtain a green body of material;
(8) Sintering: placing the formed material green body into a sintering furnace for sintering, rapidly heating to 50-100 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 20-30 min, and preserving heat for 30-50 h; the sintering temperature is 860-880 ℃.
2. The preparation method of the microwave ferrite material is characterized by comprising the following steps:
(1) The formula design is carried out according to the following composition chemical formula:
Bi a Y 3-a-b-e Ca b+e Zr b Mn c Cr d Hf e Fe 5-b-c-d-e O 12 ，
wherein a is more than or equal to 1.25 and less than or equal to 1.5,0.475, b is more than or equal to 0.6, c is more than or equal to 0.1, d is more than or equal to 0.05, and e is more than or equal to 0.05;
(2) Matching withWeighing the following materials: in Y form 2 O 3 、CaCO 3 、Fe 2 O 3 、Mn 3 O 4 、HfO 2 、Cr 2 O 5 、ZrO 2 And Bi (Bi) 2 O 3 As raw materials, weighing according to the formula proportion; wherein Bi is 2 O 3 Weighing and separating 20% -30% of the materials to obtain Bi for secondary ball milling 2 O 3 The rest part is used as the Bi of the primary ball milling 2 O 3 Material preparation;
(3) Ball milling for the first time: ball milling Bi once 2 O 3 The materials and the weighing materials of other components in the step (2) are put into a ball milling tank, and ball milling medium is added for ball milling;
(4) Presintering: drying the primary ball milling slurry and presintering;
(5) Secondary ball milling: pre-sintered powder and Bi are ball milled twice 2 O 3 Adding the materials into a ball milling medium together for secondary ball milling for 6-24 hours;
(6) Granulating: drying the slurry subjected to secondary ball milling, adding 7-8wt% of adhesive, and granulating to obtain granules;
(7) And (3) forming: pressing the granules obtained in the step (6) to obtain a green body of material;
(8) Sintering: placing the formed material green body into a sintering furnace for sintering, rapidly heating to 50-100 ℃ after heating to the sintering temperature, rapidly cooling to the sintering temperature after preserving heat for 20-30 min, and preserving heat for 30-50 h; the sintering temperature is 860-880 ℃.
3. The method of manufacturing a microwave ferrite material according to claim 2, wherein the pressure used for pressing in the step (7) is 200MPa to 300MPa.
4. The method of preparing a microwave ferrite material according to claim 2, wherein in the step (6), the binder is PVA solution, granulating by a spray drying tower, sieving with a 40 mesh sieve, and performing secondary granulation by pressing cake under 200MPa pressure, wherein the granularity is less than 1.2 μm.
5. As claimed in2, characterized in that Bi is added into the sintering furnace in the step (4) and the step (8) 2 O 3 Is a sintering boat of (2).
6. The method for adjusting the dielectric constant of a microwave ferrite material according to claim 1, wherein the dielectric constant of the microwave ferrite material is adjusted by adjusting the value of a.
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