阅读说明：本技术 一种高磁导率鳞片状铁硅铝磁粉的制备方法 (Preparation method of high-permeability scaly iron-silicon-aluminum magnetic powder ) 是由 刘立东 朱航飞 单震 于 2019-10-28 设计创作，主要内容包括：本发明属于吸波材料领域,公开了一种高磁导率鳞片状铁硅铝磁粉的制备方法。本发明所述高磁导率的鳞片状铁硅铝磁粉的制备方法包括以下步骤：选用粒度为80-180μm的铁硅铝磁粉作为原料粉,将磨球、溶剂和磁粉加入到搅拌式球磨机中,其中,溶剂为二甲基甲酰胺、二甲基亚砜中的一种或者二者的混合溶剂；利用球磨机加热装置,将溶剂和磁粉加热至80℃度后进行球磨,球磨过程中温度保持在80℃-130℃,球磨后的磁粉烘干,进行粒度分级,退火处理。该方法对传统的球磨工艺进行了优化,提高了高径厚比片状磁粉的径厚比和磁导率,同时大大提升了片状磁粉的成品率。(The invention belongs to the field of wave-absorbing materials, and discloses a preparation method of high-permeability scaly iron-silicon-aluminum magnetic powder. The preparation method of the scaly iron-silicon-aluminum magnetic powder with high magnetic conductivity comprises the following steps: selecting Fe-Si-Al magnetic powder with the granularity of 80-180 mu m as raw material powder, and adding grinding balls, a solvent and the magnetic powder into a stirring ball mill, wherein the solvent is one of or a mixed solvent of dimethylformamide and dimethyl sulfoxide; heating the solvent and the magnetic powder to 80 ℃ by using a heating device of a ball mill, carrying out ball milling, keeping the temperature at 80-130 ℃ in the ball milling process, drying the magnetic powder after ball milling, carrying out particle size grading, and annealing treatment. The method optimizes the traditional ball milling process, improves the diameter-thickness ratio and the magnetic conductivity of the high diameter-thickness ratio flaky magnetic powder, and greatly improves the yield of the flaky magnetic powder.)

1. The preparation method of the scaly iron silicon aluminum magnetic powder with high magnetic conductivity is characterized by comprising the following steps:

(1) selecting Fe-Si-Al magnetic powder with the granularity of 80-180 mu m as raw material powder;

(2) adding grinding balls, a solvent and the magnetic powder in the step (1) into a stirring ball mill, wherein the solvent is one or a mixed solvent of dimethyl formamide and dimethyl sulfoxide;

(3) heating the solvent and the magnetic powder to 80 ℃ by using a heating device of a ball mill, and then carrying out ball milling, wherein the temperature of a mixed solution of the solvent and the magnetic powder is kept between 80 ℃ and 130 ℃ in the whole ball milling process, and drying the magnetic powder after ball milling;

(4) grading the magnetic powder in the step (3) in a particle size manner;

(5) and (4) annealing the magnetic powder graded in the step (4).

2. The method for preparing scaly sendust magnetic powder with high magnetic permeability according to claim 1, wherein the magnetic powder in step (1) is spherical, blocky or irregular; preferably, the magnetic powder particle size in the step (1) is 100-150 μm.

3. The method for preparing the scale-shaped sendust magnetic powder with high permeability according to claim 1, wherein the sendust magnetic powder in step (1) comprises the following alloy components in percentage by weight: 9% -10%, Al: 5 to 6 percent of Fe and the balance of impurities, and the content of impurity elements is less than 0.8 percent.

4. The method for preparing the scaly ferrosilicoaluminophosphate magnetic powder with high magnetic conductivity according to claim 1, wherein the grinding ball in the step (2) is a steel ball or a zirconia ball, and the diameter of the grinding ball is 2-7 mm.

5. The method for preparing the scaly sendust magnetic powder with high magnetic permeability according to claim 1, wherein the mass ratio of the magnetic powder, the solvent and the grinding balls in the step (2) is 1: (3-5): (20 to 50).

6. The method for preparing scaly sendust magnetic powder with high magnetic permeability according to claim 1, wherein the temperature of the mixed solution of the solvent and the magnetic powder in the step (3) is maintained at 90 ℃ to 120 ℃, such as 90 ℃ to 100 ℃ during the whole ball milling process.

7. The method for preparing scaly sendust magnetic powder with high magnetic permeability according to claim 1, wherein the ball milling time in step (3) is 1.5-2.5 h.

8. The method for preparing the scaly sendust magnetic powder with high magnetic permeability according to claim 1, wherein the rotation speed of the ball mill in the step (3) is 100-200 rpm.

9. The method for preparing the scaly sendust magnetic powder with high magnetic permeability according to claim 1, wherein the step (4) of particle size classification is to select the magnetic powder with the ratio of diameter to thickness of less than 50:1, ratio of diameter to thickness (50: 1) to (100: 1), and ratio of diameter to thickness greater than 100: 1 magnetic powder.

10. The method for preparing the scaly sendust magnetic powder with high magnetic permeability according to claim 1, wherein the annealing temperature in the step (5) is 650 ℃ to 750 ℃; preferably, the annealing time is 30min to 90 min; further preferably, the annealing atmosphere is hydrogen or argon.

Technical Field

The invention relates to the field of wave-absorbing materials, in particular to a preparation method of high-permeability scaly iron-silicon-aluminum magnetic powder.

Background

With the rapid development of electronic information technology, the problems of electromagnetic compatibility and electromagnetic interference are increasingly prominent. There are many ways to solve the problem of electromagnetic compatibility of electronic products, such as reasonable wiring, filtering, shielding, etc. The wave-absorbing magnetic sheet material is a flexible sheet material mainly compounded by scaly soft magnetic alloy magnetic powder and a high-molecular binder, and is also called a noise suppression sheet. In recent years, the wave-absorbing magnetic sheet has higher magnetic conductivity and convenient use, and is more and more favored by electronic engineers, and the wave-absorbing magnetic sheet material is more and more used in electronic products to solve the problem of electromagnetic interference.

The electromagnetic property of the scaly soft magnetic alloy powder in the wave-absorbing magnetic sheet material is the most critical factor influencing the performance of the noise suppression sheet, and the scaly soft magnetic alloy mainly uses an iron-silicon-aluminum alloy system at present. A large number of researches show that in order to ensure that the wave-absorbing magnetic sheet has high magnetic conductivity and loss characteristics, the thickness of the scaly magnetic powder is smaller than the skin depth of the material and is generally smaller than 1 mu m, and the magnetic conductivity of the magnetic sheet is higher when the radius-thickness ratio is larger. At present, the scaly iron-silicon-aluminum magnetic powder is mainly prepared by ball milling and heat treatment. Firstly, selecting proper raw material powder, then placing the raw material powder, grinding balls, a ball-milling medium (solvent, grinding aid and the like) and the like into a ball mill according to a certain proportion for ball milling, gradually changing isotropic magnetic powder into a sheet shape under the high-speed impact and rolling of the grinding balls, then screening the flaky ferrosilicon aluminum powder, and finally placing the flaky ferrosilicon aluminum powder into an annealing furnace with gas protection for heat treatment.

The sendust powder has high hardness, is brittle, and has poor plastic deformation capability. Under the action of repeated squeezing and impacting of the grinding balls, the magnetic powder is converted into a sheet shape on one hand, and is crushed into fine powder on the other hand. Therefore, the scale-like sendust magnetic powder after ball milling is very uneven, the magnetic powder with high aspect ratio (ratio of the diameter dimension to the thickness dimension of the scale-like magnetic powder) is less, and the yield is low. Meanwhile, the edges of the magnetic powder are not smooth enough and have burrs, so that the magnetic conductivity of the magnetic powder is greatly influenced. In addition, in order to improve the ball milling efficiency and promote the deformation of the sendust magnetic powder, auxiliary materials such as a dispersing agent or a grinding aid are generally required to be added in the ball milling process, and the materials are not easy to be completely removed in the subsequent treatment process and have adverse effects on the magnetic powder magnetic permeability.

Chinese patent CN103350225A discloses a method for multi-stage rod milling to flatten soft magnetic alloy magnetic powder, which can improve the diameter-thickness ratio of magnetic powder and increase the yield, but the production process is complex, requires multi-stage ball milling, and requires long-time ball milling, and the production efficiency is low. CN104249155A discloses a multistage ball milling method, which significantly improves the flattening rate of magnetic powder compared with the conventional process, however, the process also requires multistage ball milling, the ball milling time is long, the production efficiency is low, and the process parameters need to be accurately controlled, otherwise the flattening rate of magnetic powder is seriously affected. In conclusion, the traditional preparation process of the scaly iron-silicon-aluminum magnetic powder has the problems of low yield, shape defects and the like, and an efficient preparation method of the scaly iron-silicon-aluminum magnetic powder is urgently needed.

Disclosure of Invention

The invention aims to overcome the defects of the background technology and provides a preparation method of the scaly sendust magnetic powder with high magnetic conductivity.

In order to achieve the aim of the invention, the preparation method of the scaly iron-silicon-aluminum magnetic powder with high magnetic conductivity comprises the following steps:

(1) selecting Fe-Si-Al magnetic powder with the granularity of 80-180 mu m as raw material powder;

(2) adding grinding balls, a solvent and the magnetic powder in the step (1) into a stirring ball mill, wherein the solvent is one or a mixed solvent of dimethyl formamide and dimethyl sulfoxide;

(3) heating the solvent and the magnetic powder to 80 ℃ by using a heating device of a ball mill, and then carrying out ball milling, wherein the temperature of a mixed solution of the solvent and the magnetic powder is kept between 80 ℃ and 130 ℃ in the whole ball milling process, and drying the magnetic powder after ball milling;

(4) grading the magnetic powder in the step (3) in a particle size manner;

(5) and (4) annealing the magnetic powder graded in the step (4).

Further, the magnetic powder in the step (1) is spherical, blocky or irregular.

Preferably, the magnetic powder particle size in the step (1) is 100-150 μm.

Further, in the step (1), the sendust magnetic powder comprises the following alloy components in percentage by weight: 9% -10%, Al: 5 to 6 percent of Fe and the balance of impurities, and the content of impurity elements is less than 0.8 percent.

In the invention, the material of the grinding ball in the step (2) is not limited, preferably a steel ball or a zirconia ball, the size of the grinding ball is not limited, and preferably the grinding ball with the diameter of 2-7 mm.

Further, the mass ratio of the magnetic powder, the solvent and the grinding balls in the step (2) is 1: (3-5): (20 to 50).

The stirring ball mill in the step (2) has a heating function, can adopt a hot oil or other heating modes, has a temperature monitoring function, and can monitor the temperature of the solvent in real time, wherein the temperature monitoring range is required to reach 10-200 ℃, and preferably, the temperature of the mixed solution of the solvent and the magnetic powder in the step (3) is kept at 90-120 ℃, for example, 90-100 ℃ in the whole ball milling process.

Further, the ball milling time in the step (3) is not limited, and is preferably 1.5-2.5 h.

Further, the rotation speed of the ball mill in the step (3) is 100-200 rpm.

Further, the particle size classification in the step (4) is to adopt an air flow classification technology to respectively screen out a particle size-thickness ratio smaller than 50:1, ratio of diameter to thickness (50: 1) to (100: 1), and ratio of diameter to thickness greater than 100: 1 magnetic powder.

Further, the annealing temperature in the step (5) is 650-750 ℃; preferably, the annealing time is 30min to 90 min; further preferably, the annealing atmosphere is hydrogen or argon.

Compared with the prior art, the invention has the following advantages:

(1) according to the invention, high-polarity dimethylformamide and/or dimethyl sulfoxide are/is adopted as a solvent, and the solvent has high polarity, so that the solvent not only can play a role of the solvent, but also has a good grinding aid effect, and therefore, a grinding aid or a dispersing agent is not required to be used in the invention, thereby avoiding the phenomenon that the magnetic permeability is deteriorated due to the grinding aid or the dispersing agent remaining on the surface of the magnetic powder;

(2) according to the invention, dimethylformamide and dimethyl sulfoxide with high polarity and high boiling point are used as solvents to perform high-temperature ball milling on the sendust powder, and the ball milling temperature is controlled within a certain range, and the result shows that the sendust powder ball-milled at high temperature, especially at the temperature of 90-120 ℃, has the characteristics of high ratio of diameter to thickness, smooth edge, no burr, high yield and the like; meanwhile, the high-temperature ball milling can greatly shorten the ball milling time and improve the production efficiency.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. It is to be understood that the following description is only illustrative of the present invention and is not to be construed as limiting the present invention.

The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. "optional" or "any" means that the subsequently described event or events may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

The technical features of the embodiments of the present invention may be combined with each other as long as they do not conflict with each other.