阅读说明：本技术 一种高性能铁氧体的制备方法 (Preparation method of high-performance ferrite ) 是由 潘朝 于 2020-12-28 设计创作，主要内容包括：本发明涉及磁性材料技术领域,且公开了一种高性能铁氧体的制备方法,包括如下步骤：步骤一：原材料高温预处理；步骤二：配料称量与湿磨解碎；步骤三：脱水处理,将步骤二中得到的混合物料经过卧式离心机进行脱水,脱水后得到料浆的含固量在67wt%；步骤四：分步预烧；步骤五：粉碎球磨,将步骤四中分步预烧得到的预烧料经干式球磨粉碎后,加入分散剂进行二次球磨,持续球磨18小时得到料浆；步骤六：成型；步骤七：烧结,在200℃的温度对步骤六中成形体进行热处理,除去水分。该高性能铁氧体的制备方法,具备以物相分子式Sr-((1-a-2b-c-d))Ca-aPr-bNd-bLa-cGd-dFe-((2n-x-y))Co-xZn-yO-(19)为配比,通过原材料高温预处理,湿磨解碎,分步预烧等,实现永磁铁氧体剩磁≧4550 Gs内禀矫顽力≧5500 Oe的性能的优点。(The invention relates to the technical field of magnetic materials, and discloses a preparation method of high-performance ferrite, which comprises the following steps: the method comprises the following steps: pretreating the raw materials at high temperature; step two: weighing the ingredients and performing wet grinding and crushing; step three: performing dehydration treatment, namely dehydrating the mixed material obtained in the step two by using a horizontal centrifuge, wherein the solid content of the slurry obtained after dehydration is 67 wt%; step four: pre-burning step by step; step five: grinding and ball milling, namely, grinding the pre-sintered material obtained by pre-sintering step by step in the fourth step by dry ball milling, adding a dispersing agent for secondary ball milling, and continuously ball milling for 18 hours to obtain slurry; step six: molding; step seven: sintering, heat treating the molded body in the sixth step at a temperature of 200 ℃ to remove moisture. The high propertyPreparation method of ferrite with phase molecular formula Sr (1‑a‑2b‑c‑d) Ca a Pr b Nd b La c Gd d Fe (2n‑x‑y) Co x Zn y O 19 The performance of the permanent magnetic ferrite with the remanence larger than or equal to 4550 Gs intrinsic coercive force larger than or equal to 5500 Oe is realized by high-temperature pretreatment, wet grinding and disintegration, stepwise pre-sintering and the like of raw materials for proportioning.)

1. A high performance ferrite characterized by: the phase molecular formula of the high-performance ferrite is specifically Sr_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉；

Wherein: a is 0.3 to 0.5, b is 0.02 to 0.1, c is 0.2 to 0.4, d is 0.05 to 0.15, x is 0.2 to 0.4, y is 0.05 to 0.2, and 2n-x-y is 9.5 to 11.5.

2. A high performance ferrite as claimed in claim 1, wherein: the optimal range of a is 0.34-0.46, the proportion range of b, c and d, namely c/(2b + d), is 1.5-4.2, and the optimal range is 1.9-3.8; the optimal range of x is 0.25-0.38, and the optimal range of y is 0.08-0.17.

3. A preparation method of high-performance ferrite is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: high temperature pretreatment of raw materials

Keeping the raw materials of iron oxide, strontium carbonate, calcium carbonate, lanthanum oxide, cobalt oxide, praseodymium neodymium oxide, gadolinium oxide and zinc oxide at the high temperature of 300 ℃ for 1 hour respectively, then sealing and storing, and reducing the temperature of the raw materials to be below 60 ℃;

step two: ingredient weighing and wet grinding disintegrating

The preparation method comprises the following steps of mixing materials according to the molecular formula Sr_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉The mole ratio of the permanent magnetic ferrite main phase raw material after high-temperature pretreatment in the first step is weighed: wherein a is 0.3-0.5, b is 0.02-0.1, c is 0.2-0.4, d is 0.05-0.15, x is 0.2-0.4, y is 0.05-0.2, and 2n-x-y is 9.5-11.5;

carrying out wet ball milling and crushing on the proportioned raw materials, adding a primary additive into the proportioned raw materials, putting the mixed materials into a wet ball mill for carrying out wet milling and crushing, and carrying out material crushing in the ball mill: water: the ball ratio is 1:1.2:3, the rotating speed of the ball mill is reduced to 22r/min after frequency conversion, and fine grinding is carried out for 1.5h to obtain slurry with the passing rate of a 200-mesh screen being 99%;

step three: dehydration treatment

Dehydrating the mixed material obtained in the step two by using a horizontal centrifuge, wherein the solid content of slurry obtained after dehydration is 67 wt%;

step four: step-by-step burn-in

Performing first-step granulation pre-sintering on the mixed material obtained after dehydration treatment in the third step in a first rotary kiln, controlling the pre-sintering temperature at 800-;

step five: crushing ball mill

Pre-sintering materials obtained in the fourth step are subjected to dry ball milling and crushing, then dispersing agents are added for secondary ball milling, and the ball milling is continued for 18 hours to obtain slurry;

step six: shaping of

Dehydrating the slurry obtained in the fifth step by using a centrifugal machine, wherein the solid content of the slurry obtained after dehydration is 73wt%, and then placing the obtained slurry in a 700KA/M magnetic field for compression molding;

step seven: sintering

And (3) carrying out heat treatment on the formed body in the sixth step at the temperature of 200 ℃, removing water, and then sintering in the atmosphere, wherein the sintering temperature is controlled to be 1190-1260 ℃, so as to obtain the sintered permanent magnet.

4. The method for preparing high-performance ferrite according to claim 3, wherein the method comprises the following steps: in the second step, the primary additive is boric acid and silicon micropowder, and the addition proportion of the primary additive is that 0.2kg of boric acid and 0.4kg of silicon oxide are added into every 100kg of raw materials.

5. The method for preparing high-performance ferrite according to claim 3, wherein the method comprises the following steps: and D, using phi 4.8mm bearing steel for the balls in the wet ball mill in the step II.

6. The method for preparing high-performance ferrite according to claim 3, wherein the method comprises the following steps: and in the fifth step, the dispersing agent is added according to the following weight ratio, and the total amount of the dispersing agent added to each 100kg of the pre-sintering material is 0.1 kg.

7. The method for preparing high-performance ferrite according to claim 3, wherein the method comprises the following steps: and the dispersant in the fifth step is calcium gluconate or sorbitol.

Technical Field

The invention relates to the technical field of magnetic materials, in particular to a preparation method of high-performance ferrite.

Background

In the modern society, with the rapid development of the electronic industry, the demand of magnetic materials is more and more, although China is a large country for producing magnetic materials, the product size precision and the performance grade of the magnetic materials are different from those of developed countries, and as one kind of magnetic materials, the permanent magnetic ferrite is the most widely applied magnetic material at present, particularly, the high-performance permanent magnetic ferrite material is a basic functional material for the contemporary society and the development thereof, and along with the development trend of miniaturization and lightness and thinness of various electronic and electric products, the requirement on the performance of the ferrite is higher and higher.

At present, the existing strontium barium ferrite and calcium lanthanum cobalt ferrite developed at home and abroad based on an ion substitution technology are not enough to meet the requirement of miniaturization of electronic products on the increasingly high magnetic property of the permanent magnetic ferrite, and the performance that the residual magnetism is larger than or equal to 4500Gs intrinsic coercive force is larger than or equal to 5500 Oe still cannot be realized at the highest, for example, the idea that La and Co are used for replacing Sr and Fe respectively disclosed by patent CN 1335997A realizes Br 4450Gs and Hcj 4460 Oe, and the magnetic properties Br4500Gs and Hcj3200 Oe disclosed by patent CN 102945718A.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a preparation method of high-performance ferrite, which has Sr in a phase molecular formula_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉The method has the advantages that the performance that the residual magnetism of the permanent magnetic ferrite is larger than or equal to 4550 Gs intrinsic coercive force is larger than or equal to 5500 Oe is realized through high-temperature pretreatment, wet grinding and breaking, stepwise pre-sintering and the like of raw materials, and the problems that the existing strontium barium ferrite and the calcium lanthanum cobalt ferrite developed at home and abroad based on the ion substitution technology are not enough to meet the requirement that the miniaturization of electronic products is higher and higher on the magnetic property of the permanent magnetic ferrite, and the performance that the residual magnetism is larger than or equal to 4500Gs intrinsic coercive force is not larger than or equal to 5500 Oe at most are solved.

(II) technical scheme

To achieve Sr in the molecular formula of phase_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉In order to match, the purpose of realizing the performance of the permanent magnetic ferrite with the remanence larger than or equal to 4550 Gs intrinsic coercive force larger than or equal to 5500 Oe is realized through high-temperature pretreatment of raw materials, wet grinding, disintegration, stepwise pre-sintering and the like, the invention provides the following technical scheme: a high-performance ferrite with Sr as its molecular formula_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉；

Wherein: a is 0.3 to 0.5, b is 0.02 to 0.1, c is 0.2 to 0.4, d is 0.05 to 0.15, x is 0.2 to 0.4, y is 0.05 to 0.2, and 2n-x-y is 9.5 to 11.5.

Preferably, the optimal range of a is 0.34-0.46, the proportion range of b, c and d, namely c/(2b + d), is 1.5-4.2, and the optimal range is 1.9-3.8; the optimal range of x is 0.25-0.38, and the optimal range of y is 0.08-0.17.

A preparation method of high-performance ferrite comprises the following steps:

the method comprises the following steps: high temperature pretreatment of raw materials

Keeping the raw materials of iron oxide, strontium carbonate, calcium carbonate, lanthanum oxide, cobalt oxide, praseodymium neodymium oxide, gadolinium oxide and zinc oxide at the high temperature of 300 ℃ for 1 hour respectively, then sealing and storing, and reducing the temperature of the raw materials to be below 60 ℃;

step two: ingredient weighing and wet grinding disintegrating

The preparation method comprises the following steps of mixing materials according to the molecular formula Sr_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉The mole ratio of the permanent magnetic ferrite main phase raw material after high-temperature pretreatment in the first step is weighed: wherein a is 0.3-0.5, b is 0.02-0.1, c is 0.2-0.4, d is 0.05-0.15, x is 0.2-0.4, y is 0.05-0.2, and 2n-x-y is 9.5-11.5;

carrying out wet ball milling and crushing on the proportioned raw materials, adding a primary additive into the proportioned raw materials, putting the mixed materials into a wet ball mill for carrying out wet milling and crushing, and carrying out material crushing in the ball mill: water: the ball ratio is 1:1.2:3, the rotating speed of the ball mill is reduced to 22r/min after frequency conversion, and fine grinding is carried out for 1.5h to obtain slurry with the passing rate of a 200-mesh screen being 99%;

step three: dehydration treatment

Dehydrating the mixed material obtained in the step two by using a horizontal centrifuge, wherein the solid content of slurry obtained after dehydration is 67 wt%;

step four: step-by-step burn-in

Performing first-step granulation pre-sintering on the mixed material obtained after dehydration treatment in the third step in a first rotary kiln, controlling the pre-sintering temperature at 800-;

step five: crushing ball mill

Pre-sintering materials obtained in the fourth step are subjected to dry ball milling and crushing, then dispersing agents are added for secondary ball milling, and the ball milling is continued for 18 hours to obtain slurry;

step six: shaping of

Dehydrating the slurry obtained in the fifth step by using a centrifugal machine, wherein the solid content of the slurry obtained after dehydration is 73wt%, and then placing the obtained slurry in a 700KA/M magnetic field for compression molding;

step seven: sintering

And (3) carrying out heat treatment on the formed body in the sixth step at the temperature of 200 ℃, removing water, and then sintering in the atmosphere, wherein the sintering temperature is controlled to be 1190-1260 ℃, so as to obtain the sintered permanent magnet.

Preferably, the first additive in the second step is boric acid and silica powder, and the adding proportion of the first additive is 0.2kg of boric acid and 0.4kg of silica per 100kg of raw material.

Preferably, phi 4.8mm bearing steel is used for the balls in the wet ball mill in the second step.

Preferably, the dispersant in the fifth step is added according to the following weight ratio, and the total amount of the dispersant added per 100kg of the pre-sintering material is 0.1 kg.

Preferably, the dispersant in the fifth step is calcium gluconate or sorbitol.

(III) advantageous effects

Compared with the prior art, the invention provides a preparation method of high-performance ferrite, which has the following beneficial effects:

1. according to the preparation method of the high-performance ferrite, the raw materials of iron oxide, strontium carbonate, calcium carbonate, lanthanum oxide, cobalt oxide, praseodymium neodymium oxide, gadolinium oxide and zinc oxide are respectively subjected to heat preservation at the high temperature of 300 ℃ for 1 hour and then are stored in a sealing manner, so that the moisture and volatile substances in the raw materials can be effectively removed, the raw material proportion is more accurate, and the formula volatility is reduced.

2. According to the preparation method of the high-performance ferrite, steel balls with the particle size phi of 4.8mm are used in a ball mill for wet grinding and disintegration by virtue of ingredient weighing, and are subjected to speed reduction grinding, so that the molecular structure of the raw material can be maintained to a large extent, the passing rate of a 200-mesh screen is controlled, uniformly dispersed slurry is obtained, and the raw material is not easy to crystallize in a pre-sintering link.

3. According to the preparation method of the high-performance ferrite, the step-by-step pre-sintering method is adopted, when the first-step granulation pre-sintering is carried out, materials pass through slowly, the raw materials are fully decomposed and then rapidly pass through the second-step high-temperature pre-sintering stage to carry out solid-phase reaction, the influence of decomposed volatile matters of the raw materials on the solid-phase reaction is reduced, the obtained granular materials are more compact, and the performance is improved.

4. According to the preparation method of the high-performance ferrite, the obtained pre-sintering powder only needs to be added with a dispersing agent during secondary grinding, and the dispersing agent can improve the orientation of slurry particles during magnetic field forming, so that the slurry is easier to orient; different from the conventional ball milling process, the other additives such as calcium carbonate and silicon oxide are not added for the second time, but are added for the first time, which is beneficial to improving the performance.

5. The phase molecular formula of the high-performance ferrite prepared by the preparation method is specifically Sr_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉The performance of permanent magnetic ferrite residual magnetism ≧ 4550 Gs intrinsic coercive force ≧ 5500 Oe is realized through the process of the pre-sintering material。

Drawings

FIG. 1 is a table showing the molecular formula of ferrite obtained by the method for preparing a high performance ferrite according to the present invention;

FIG. 2 is a table of magnetic properties of a method for preparing a high performance ferrite according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to FIGS. 1-2, a high performance ferrite having a phase formula of Sr_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉；

Wherein: a is 0.3 to 0.5, b is 0.02 to 0.1, c is 0.2 to 0.4, d is 0.05 to 0.15, x is 0.2 to 0.4, y is 0.05 to 0.2, and 2n-x-y is 9.5 to 11.5.

The optimal range of a is 0.34-0.46, the ratio range of b, c and d, namely c/(2b + d), is 1.5-4.2, and the optimal range is 1.9-3.8; the optimal range of x is 0.25-0.38, and the optimal range of y is 0.08-0.17.

A preparation method of high-performance ferrite comprises the following steps:

the method comprises the following steps: high temperature pretreatment of raw materials

Keeping the raw materials of iron oxide, strontium carbonate, calcium carbonate, lanthanum oxide, cobalt oxide, praseodymium neodymium oxide, gadolinium oxide and zinc oxide at the high temperature of 300 ℃ for 1 hour respectively, then sealing and storing, and reducing the temperature of the raw materials to be below 60 ℃;

step two: ingredient weighing and wet grinding disintegrating

The preparation method comprises the following steps of mixing materials according to the molecular formula Sr_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉The mole ratio of the permanent magnetic ferrite main phase raw material after high-temperature pretreatment in the first step is weighed: wherein a is 0.3-0.5, b is 0.02-0.1, c is 0.2-0.4, d is 0.05-0.15, x is 0.2-0.4, y is 0.05-0.2, and 2n-x-y is 9.5-11.5;

carrying out wet ball milling and crushing on the proportioned raw materials, adding a primary additive into the proportioned raw materials, putting the mixed materials into a wet ball mill for carrying out wet milling and crushing, and carrying out material crushing in the ball mill: water: the ball ratio is 1:1.2:3, the rotating speed of the ball mill is reduced to 22r/min after frequency conversion, and fine grinding is carried out for 1.5h to obtain slurry with the passing rate of a 200-mesh screen being 99%;

step three: dehydration treatment

Dehydrating the mixed material obtained in the step two by using a horizontal centrifuge, wherein the solid content of slurry obtained after dehydration is 67 wt%;

step four: step-by-step burn-in

Performing first-step granulation pre-sintering on the mixed material obtained after dehydration treatment in the third step in a first rotary kiln, controlling the pre-sintering temperature at 800-;

step five: crushing ball mill

Pre-sintering materials obtained in the fourth step are subjected to dry ball milling and crushing, then dispersing agents are added for secondary ball milling, and the ball milling is continued for 18 hours to obtain slurry;

step six: shaping of

Dehydrating the slurry obtained in the fifth step by using a centrifugal machine, wherein the solid content of the slurry obtained after dehydration is 73wt%, and then placing the obtained slurry in a 700KA/M magnetic field for compression molding;

step seven: sintering

And (3) carrying out heat treatment on the formed body in the sixth step at the temperature of 200 ℃, removing water, and then sintering in the atmosphere, wherein the sintering temperature is controlled to be 1190-1260 ℃, so as to obtain the sintered permanent magnet.

In the second step, the primary additive is boric acid and silicon micropowder, and the addition proportion of the primary additive is that 0.2kg of boric acid and 0.4kg of silicon oxide are added into every 100kg of raw materials.

And D, using phi 4.8mm bearing steel for the balls in the wet ball mill in the step II.

In the fifth step, the dispersant is added according to the following weight ratio, and the total amount of the dispersant added in each 100kg of the pre-sintering material is 0.1 kg.

And the dispersant in the fifth step is calcium gluconate or sorbitol.

In conclusion, the preparation method of the high-performance ferrite can effectively remove water and volatile substances in raw materials by respectively preserving heat of the raw materials of iron oxide, strontium carbonate, calcium carbonate, lanthanum oxide, cobalt oxide, praseodymium neodymium oxide, gadolinium oxide and zinc oxide at the high temperature of 300 ℃ for 1 hour and then sealing and storing the raw materials, so that the proportion of the raw materials is more accurate, the formula fluctuation is reduced, bearing steel small-particle-size steel balls with the diameter of 4.8mm are used by a ball mill in the process of batching, weighing and wet grinding and crushing, the speed is reduced for grinding, the molecular structure of the raw materials can be greatly maintained, the passing rate of a 200-mesh screen is controlled to obtain uniformly dispersed slurry, the raw materials are not easy to crystallize in a pre-sintering link, the materials pass slowly in the process of first-step pre-sintering granulation, the raw materials are fully decomposed and then rapidly pass through a second-step high-temperature pre-sintering stage for solid phase reaction, the influence of the volatile matters decomposed by the raw materials on the solid phase reaction is reduced, the obtained granular material is more compact, the performance is improved, the dispersing agent is only needed to be added when the obtained pre-sintering powder is subjected to secondary grinding, the orientation of slurry particles during magnetic field forming can be improved by the dispersing agent, and the slurry is easier to orient; different from the conventional ball milling process, the calcium carbonate, the silicon oxide and the like which are other additives are not added for the second time but added for the first time, which is beneficial to improving the performance, and the phase molecular formula of the prepared high-performance ferrite is specifically Sr_(1-a-2b-c-d)Ca_aPr_bNd_bLa_cGd_dFe_(2n-x-y)Co_xZn_yO₁₉The permanent magnetic ferrite residual magnetism is not less than 4550 Gs intrinsic coercive force not less than 5500 Oe by the process of the pre-sintering material.

It is to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.