阅读说明：本技术 一种制造铋钙钒石榴石铁氧体材料的方法 (Method for manufacturing bismuth calcium vanadium garnet ferrite material ) 是由 卢杨成 杨辉 雷青松 于 2021-09-24 设计创作，主要内容包括：本发明涉及一种制造铋钙钒石榴石铁氧体材料的方法,步骤如下：配方按摩尔份计,Bi：1.1～1.3份、Ca：1.7～1.9份、V：1.0～1.2份、Zr：0.25～0.35份、In：0.35～0.45份、Fe：3.1～3.2份；将原料按配方计算的重量进行计量配制,经球磨机进行湿法混合、烘干后进行预烧,得到预烧料后,将所述预烧料进行湿法球磨粉碎,达到一定粒度后出料烘干,将得到的粉料加入一定量的PVA溶液混合均匀,经过预压成型,破碎造粒,得到粒径均匀的颗粒料后进行干压成型、充氧烧结、精密磨加工的到铋钙钒石榴石铁氧体材料磁体。本发明具有工艺技术先进,磁性能参数好,在微波环行器隔离器中使用器件插入损耗低,工作温度高,工作稳定性好等特点,为微波环行器隔离器提供了良好稳定的旋磁场。(The invention relates to a method for manufacturing a bismuth calcium vanadium garnet ferrite material, which comprises the following steps: the formula comprises the following components in parts by mole: 1.1-1.3 parts of Ca: 1.7-1.9 parts of V: 1.0-1.2 parts of Zr: 0.25-0.35 parts of In: 0.35-0.45 parts of Fe: 3.1-3.2 parts; the raw materials are measured and prepared according to the weight calculated by the formula, wet mixing is carried out through a ball mill, pre-sintering is carried out after drying, after a pre-sintering material is obtained, wet ball milling and crushing are carried out on the pre-sintering material, discharging and drying are carried out after a certain particle size is reached, a certain amount of PVA solution is added into the obtained powder, the obtained powder is uniformly mixed, pre-pressing forming and crushing granulation are carried out, and then the bismuth calcium vanadium garnet ferrite material magnet is processed through dry pressing forming, oxygen-charged sintering and precision grinding after the particle material with uniform particle size is obtained. The invention has the advantages of advanced process technology, good magnetic performance parameters, low insertion loss of devices used in the microwave circulator isolator, high working temperature, good working stability and the like, and provides a good and stable rotating magnetic field for the microwave circulator isolator.)

1. A method for manufacturing a bismuth calcium vanadium garnet ferrite material is characterized by comprising the following steps: the method comprises the following steps:

(1) preparing materials: the formula comprises the following components in parts by mole: 1.1-1.3 parts of Ca: 1.7-1.9 parts of V: 1.0-1.2 parts of Zr: 0.25-0.35 parts of In: 0.35-0.45 parts of Fe: 3.1-3.2 parts by weight of raw materials calculated according to the formula;

(2) mixing: adopting a planetary ball mill to prepare a mixture according to the weight ratio of material balls to water of 1: 3: 1.5, performing wet ball milling for 8 hours;

(3) drying and pre-sintering: drying at 200 ℃, introducing oxygen into an atmosphere sintering furnace, keeping the temperature of 1200-1220 ℃ for 5 hours, and naturally cooling;

(4) ball milling: adopting a rolling ball mill to obtain a material ball water weight ratio of 1: 5: 2, performing wet ball milling and crushing to reach the granularity of 0.85 mu;

(5) drying and granulating: drying at 200 ℃, adding 8 wt% of polyvinyl alcohol solution into the powder, uniformly mixing, wherein the concentration of the polyvinyl alcohol solution is 8-10%, prepressing into blocks, crushing and granulating into granules with the radius of 0.18-0.25 mm;

(6) molding: molding the die to achieve the green density of 3.0 +/-0.1 g/cm 3;

(7) and (3) sintering: preserving heat for 5 hours at 1350-1400 ℃ in an atmosphere sintering furnace for sintering, wherein the oxygen content in the furnace is more than or equal to 30%, and naturally cooling along with the furnace;

(8) grinding: grinding meets the requirement of drawing size.

2. The method of making a bismuth calcium vanadium garnet ferrite material as claimed in claim 1, characterized in that: in the step (1), Bi with qualified purity is added₂O₃、CaCO₃、V₂O₃、ZrO₂、In₂O₃、Fe₂O₃The raw materials are measured according to the weight calculated by the formula, and Ca is added in the pre-sintering and sintering processes²⁺Substituted A site ion Bi²⁺，In³⁺、Zr⁴⁺、V⁵⁺Substituted ion Fe at B position³⁺The bismuth calcium vanadium garnet ferrite material with low Ms, narrow delta H, low tan delta epsilon and high Tc is prepared.

3. The method of making a bismuth calcium vanadium garnet ferrite material as claimed in claim 1, characterized in that: in the step (4), high-purity zirconia balls are selected as ball milling media.

4. The method of making a bismuth calcium vanadium garnet ferrite material as claimed in claim 1, characterized in that: in the step (5), the pre-pressing crushing is carried out, a 60-mesh sieve and an 80-mesh sieve are used in a combined mode, particles which are sieved by the 60-mesh sieve and not sieved by the 80-mesh sieve are selected as final forming particles, and the radius of the particles is 0.18-0.25 mm.

Technical Field

The invention relates to the field of microwave ferrite, in particular to a method for preparing a bismuth calcium vanadium garnet ferrite material.

Background

With the continuous development of the electronic information industry, higher requirements are put on microwave devices in various radio communication equipment. As the core of the microwave ferrite device, various properties of the ferrite material, such as saturation magnetization (Ms), ferromagnetic resonance line width (Δ H), dielectric constant (∈), dielectric loss (tan δ ∈), curie temperature (Tc), and the like, are important. The bismuth calcium vanadium garnet ferrite material has multiple advantages of narrow ferromagnetic resonance line width delta H, dielectric loss (tan delta epsilon), low saturation magnetization intensity (Ms) and the like, is widely applied to microwave circulators and isolators in various frequency bands, and plays a role in promoting the development of microwave technology.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a method for manufacturing a bismuth calcium vanadium garnet ferrite material, wherein the obtained bismuth calcium vanadium garnet ferrite material is used in a microwave circulator isolator used in a lower frequency band, so that the insertion loss of a device can be effectively reduced, the bandwidth, the working temperature and the working stability of the device can be improved, and the application range of the microwave circulator isolator is expanded.

The object of the present invention is achieved by the following technical means. A method for manufacturing a bismuth calcium vanadium garnet ferrite material comprises the following steps:

(1) preparing materials: the formula comprises the following components in parts by mole: 1.1-1.3 parts of Ca: 1.7-1.9 parts of V: 1.0-1.2 parts of Zr: 0.25-0.35 parts of In: 0.35-0.45 parts of Fe: 3.1-3.2 parts by weight of raw materials calculated according to the formula;

(2) mixing: adopting a planetary ball mill to prepare a mixture according to the weight ratio of material balls to water of 1: 3: 1.5, performing wet ball milling for 8 hours;

(3) drying and pre-sintering: drying at 200 ℃, introducing oxygen into an atmosphere sintering furnace, keeping the temperature of 1200-1220 ℃ for 5 hours, and naturally cooling;

(4) ball milling: adopting a rolling ball mill to obtain a material ball water weight ratio of 1: 5: 2, performing wet ball milling and crushing to reach the granularity of 0.85 mu;

(5) drying and granulating: drying at 200 ℃, adding 8 wt% of polyvinyl alcohol solution into the powder, uniformly mixing, wherein the concentration of the polyvinyl alcohol solution is 8-10%, prepressing into blocks, crushing and granulating into granules with the radius of 0.18-0.25 mm;

(6) molding: molding the die to achieve the green density of 3.0 +/-0.1 g/cm 3;

(7) and (3) sintering: preserving heat for 5 hours at 1350-1400 ℃ in an atmosphere sintering furnace for sintering, wherein the oxygen content in the furnace is more than or equal to 30%, and naturally cooling along with the furnace;

(8) grinding: grinding meets the requirement of drawing size.

Preferably, in the step (1), Bi having an acceptable purity is used₂O₃、CaCO₃、V₂O₃、ZrO₂、In₂O₃、Fe₂O₃The raw materials are measured according to the weight calculated by the formula, and Ca is adopted in the pre-sintering and sintering processes²⁺Substituted A site ion Bi²⁺In is used³⁺、Zr⁴⁺、V⁵⁺Substituted ion Fe at B position³⁺The bismuth calcium vanadium garnet ferrite material with low Ms, narrow delta H, low tan delta epsilon and high Tc is prepared.

Preferably, in step (4), high-purity zirconia balls are selected as the ball milling medium.

Preferably, in the step (5), after pre-pressing and crushing, 60-mesh and 80-mesh sieves are used in combination, and particles which pass through the 60-mesh sieve and do not pass through the 80-mesh sieve are selected as final forming particles, wherein the particle radius is between 0.18 and 0.25 mm.

Preferably, oxygen is introduced during the pre-sintering and sintering processes, so that the oxygen content in the furnace is more than or equal to 30 percent.

The invention has the beneficial effects that: the material of the invention is a garnet ferrite material without yttrium, and has the advantages of low magnetic moment, low ferromagnetic resonance line width, low dielectric loss, high Curie temperature and the like. The invention has the advantages of advanced process technology, good magnetic performance parameters, low insertion loss of devices used in the microwave circulator isolator, high working temperature, good working stability and the like, and provides a good and stable rotating magnetic field for the microwave circulator isolator.

Detailed Description

The present invention will now be described in detail with reference to examples, but it is to be understood that these examples are not intended to limit the scope of the invention, and that various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention.

The invention relates to a method for manufacturing a bismuth calcium vanadium garnet ferrite material, which comprises the steps of metering and preparing raw materials according to the weight calculated by a formula, carrying out wet mixing by a ball mill, drying, then presintering to obtain a presintering material, carrying out wet ball milling and crushing on the presintering material, discharging and drying after reaching a certain particle size, adding a certain amount of PVA solution into the obtained powder, uniformly mixing, carrying out prepressing molding, crushing and granulating to obtain a particle material with uniform particle size, and then carrying out dry pressing molding, oxygen-charging sintering and precision grinding to obtain a bismuth calcium vanadium garnet ferrite material magnet; the method comprises the following specific steps:

(1) preparing materials: the formula comprises the following components in parts by mole: 1.1-1.3 parts of Ca: 1.7-1.9 parts of V: 1.0-1.2 parts of Zr: 0.25-0.35 parts of In: 0.35-0.45 parts of Fe: 3.1 to 3.2 portions of Bi with qualified purity₂O₃、CaCO₃、V₂O₃、ZrO₂、In₂O₃、Fe₂O₃The raw materials are measured according to the weight calculated by the formula, and Ca is adopted in the pre-sintering and sintering processes²⁺Substituted A site ion Bi²⁺In is used³⁺、Zr⁴⁺、V⁵⁺Substituted ion Fe at B position³⁺The bismuth calcium vanadium garnet ferrite material with low Ms, narrow delta H, low tan delta epsilon and high Tc is prepared.

(2) Mixing: adopting a planetary ball mill to prepare a mixture according to the weight ratio of material balls to water of 1: 3: 1.5, performing wet ball milling for 8 hours;

(3) drying and pre-sintering: drying at 200 ℃, introducing oxygen into an atmosphere sintering furnace, keeping the temperature of 1200-1220 ℃ for 5 hours, and naturally cooling;

(4) ball milling: adopting a rolling ball mill to obtain a material ball water weight ratio of 1: 5: 2, performing wet ball milling and crushing to reach the granularity of 0.85 mu;

(5) drying and granulating: drying at 200 ℃, adding 8 wt% of polyvinyl alcohol solution into the powder, uniformly mixing, wherein the concentration of the polyvinyl alcohol solution is 8-10%, prepressing into blocks, crushing and granulating into granules with the radius of 0.18-0.25 mm;

(6) molding: molding the die to achieve the green density of 3.0 +/-0.1 g/cm 3;

(7) and (3) sintering: preserving heat for 5 hours at 1350-1400 ℃ in an atmosphere sintering furnace for sintering, wherein the oxygen content in the furnace is more than or equal to 30%, and naturally cooling along with the furnace;

(8) grinding: grinding meets the requirement of drawing size.

The invention solves the technical problems that:

1. the performance of the magnet is improved by adopting an ion substitution technology, selecting proper added ions as formula raw materials and selecting proper substitution amount.

Experiments have shown that by adding In³⁺、Zr⁴⁺Fe substituted in position B³⁺Can effectively reduce the ferromagnetic resonance line width delta H and the dielectric loss tan delta epsilon, improve the performance of the magnet, and the optimal addition amount of In and Zr is 0.4 to 0.3 molar ratio.

The line width of garnet ferrite materials is determined by the anisotropy constant K1, and a narrow line width requires a low anisotropy constant K1. However, in the case of only Fe³⁺In the garnet material which is magnetic ion, the anisotropy of the material is mainly composed of Fe on octahedral position³⁺The resulting, therefore, displacement of the nonmagnetic ions in the octahedral position may lower K1. In the octahedral position with In³⁺And Zr⁴⁺Substitution of Fe³⁺To reduce magnetocrystalline anisotropy, and Zr⁴⁺And Ca²⁺Can achieve the effect of price balance by replacing and simultaneously adopting V⁵⁺Fe replacing tetrahedral position³⁺The saturation magnetization can be reduced without lowering the curie temperature.

Through experiments on the relationship between the change of the In3+ substitution amount (molar ratio) and the Δ H, when the substitution amount is less than or equal to 0.4, the Δ H is obviously reduced along with the increase of the substitution amount, and after the substitution amount is more than 0.4, the Δ H is not obviously reduced, so that the optimal addition amount of In is 0.4 molar ratio; when V is⁵⁺Since a single-phase solid solution cannot be formed when the substitution amount of (B) is less than 0.9, the addition amount of V in the present invention is selected to be 1.1 mol.

2. Research on the selection of new ball milling medium in the ball milling process to improve the magnetic property of the material

The traditional ball milling medium is generally steel balls which are easy to oxidize and can be worn in the ball milling process, the worn Fe can be mixed into the material to cause excessive iron in the powder, and the Fe is generated after pre-sintering²⁺And the Ms of the material is influenced, so that the high-purity zirconia balls are used as a ball milling medium in the ball milling process, and the zirconia balls have the characteristics of high strength, good wear resistance, good toughness and the like, can effectively avoid the generation of Fe2+, and ensure the Ms of the material.

3. The relationship between the size and the properties of the crushed particles after the pre-compression molding was investigated.

It has been found that if the particle size is too large, the density of the sintered material is too low, and if the size is too small, the pressed green body will crack during forming, and if the particle size is not uniform, the material properties will be poor, and good magnetic properties will only be obtained if the particle size is 0.18-0.25 mm.

4. The influence of the pre-sintering temperature and the sintering temperature on the magnetic property of the material and the influence of oxygen introduction on the magnetic property of the material are researched

The aim of the pre-sintering is to cause solid-phase reaction between raw material particles, so that most raw materials are changed into ferrite, and the volume of the pre-sintered material is obviously shrunk, thereby reducing the shrinkage rate of the sintered product and reducing the possibility of deformation of the product; the sintering aims at making ferrite solid-phase reaction complete, reducing the air holes of the product, reducing the Delta H of the material and ensuring the Ms of the material. According to the experimental surface, the best performance can be obtained when the pre-sintering temperature is 1200-1220 ℃, the sintering temperature is 1350-1400 ℃ and the heat preservation is carried out for 5 hours. Oxygen is introduced in the pre-sintering and sintering processes to effectively lead Fe generated in the reaction process²⁺Is oxidized into Fe³⁺Ms of the material can be ensured.

The magnetic performance parameter indexes of the bismuth calcium vanadium garnet ferrite material are as follows:

saturation magnetization Ms: 64 KA/m;

ferromagnetic resonance line width Δ H: 1.8KA/m

Dielectric constant ε: 15

Dielectric loss tan δ ∈: 2X 10^-4

Curie temperature Tc: 230 deg.C

Example (b): the method for preparing the bismuth calcium vanadium garnet ferrite material comprises the following process flows: the method comprises the following steps of proportioning, mixing, drying, presintering, ball milling, drying, prepressing, granulating, molding, sintering, grinding, sorting, testing and warehousing, and comprises the following specific steps:

fe2O3 with the purity of 98 percent and Bi with the purity of 97 percent are adopted₂O₃、CaCO₃、V₂O₃、ZrO₂、In₂O₃The raw materials are measured according to the weight calculated by the formula, and are mixed by a planetary ball mill according to the ratio of material balls to water of 1: 3: 1.5, performing wet mixing for 8 hours, drying at 200 ℃ in a drying furnace to obtain dry powder, presintering at 1210 ℃ in an atmosphere sintering furnace, preserving heat for 5 hours, naturally cooling along with the furnace to obtain a presintering material, and mixing the presintering material in a rolling ball mill according to a ball-to-water ratio of 1: 5: 2, performing wet ball milling, discharging after the particle size reaches 0.85 mu, drying at 200 ℃, adding 8 wt% of PVA solution (concentration 10%) into the dried powder, uniformly mixing, performing 4MPa pressure pre-pressing molding, crushing granulation, screening by adopting a 60-mesh and 80-mesh combined screen, selecting particles which pass through a 60-mesh screen and do not pass through a 80-mesh screen, molding to obtain a green blank product with the density of 3.0g/cm3 by using a dry pressing molding machine, sintering at 1370 ℃ by using an atmosphere sintering furnace, introducing oxygen, ensuring that the oxygen content in the furnace is more than 30%, preserving heat for 5 hours, naturally cooling along with the furnace, and processing the product to the requirements of a product use drawing by using a full-automatic grinding machine.

TABLE 1 attached magnetic performance index of bismuth calcium vanadium garnet ferrite material

In the present invention, Ca is used²⁺Substituted A site ion Bi²⁺In is used³⁺、Zr⁴⁺、V⁵⁺Substituted ion Fe at B position³⁺The bismuth calcium vanadium garnet ferrite material with low Ms, narrow delta H, low tan delta epsilon and high Tc is prepared.

In the invention, high-purity zirconia balls are used as ball milling media, so that steel balls are avoided, the steel balls are abraded in the ball milling process, the abraded Fe is mixed into the material to cause excessive iron in the powder, and the Fe is generated after pre-sintering²⁺Influences Ms of the material, and the zirconia ball has the characteristics of high strength, good wear resistance, good toughness and the like, and can effectively avoid Fe²⁺Ensuring Ms of the material.

According to the invention, 60-mesh and 80-mesh sieves are combined for use, and particles which pass through the 60-mesh sieve and do not pass through the 80-mesh sieve are selected as final forming particles, so that the radius of the particles can be ensured to be 0.18-0.25 mm.

The main representative technical indexes in the trial production process are as follows:

it should be understood that equivalent substitutions and changes to the technical solution and the inventive concept of the present invention should be made by those skilled in the art to the protection scope of the appended claims.