阅读说明：本技术 负热膨胀系数高绝缘特性的软磁金属粉末及其制备方法 (Soft magnetic metal powder with negative thermal expansion coefficient and high insulation property and preparation method thereof ) 是由 李伟健 李媛媛 刘国安 方玲 柳军涛 钱小龙 于 2020-04-14 设计创作，主要内容包括：本发明提出一种负热膨胀系数高绝缘特性的软磁金属粉末及其制备方法。制备方法包括以下步骤：将软磁金属粉末真空热处理；制备纳米氢氧化锆溶液、纳米钨酸铝溶液、磷酸二氢铝溶液并混合均匀,加入磷酸进行滴定,调节溶液pH值为3-4,得到混合溶液；将真空热处理后的软磁金属粉末加入混合溶液内,超声波处理45-90分钟,加热至110℃,搅拌,得到预成品；将预成品进行气氛保护热处理,处理温度为500-650℃,时间为3-6小时,冷却至室温得到负热膨胀系数高绝缘特性的软磁金属粉末。本发明通过复合反应,制备了具有负热膨胀系数的软磁金属粉末,可以降低粉末及产品的热膨胀问题,同时也在粉末表面更好地形成包覆绝缘层,大幅提升了粉末的绝缘特性。(The invention provides soft magnetic metal powder with negative thermal expansion coefficient and high insulation property and a preparation method thereof. The preparation method comprises the following steps: carrying out vacuum heat treatment on the soft magnetic metal powder; preparing a nano zirconium hydroxide solution, a nano aluminum tungstate solution and an aluminum dihydrogen phosphate solution, uniformly mixing, adding phosphoric acid for titration, and adjusting the pH value of the solution to 3-4 to obtain a mixed solution; adding the soft magnetic metal powder subjected to vacuum heat treatment into the mixed solution, performing ultrasonic treatment for 45-90 minutes, heating to 110 ℃, and stirring to obtain a preform; and (3) carrying out atmosphere protection heat treatment on the preformed product at the temperature of 500-650 ℃ for 3-6 hours, and cooling to room temperature to obtain the soft magnetic metal powder with the negative thermal expansion coefficient and the high insulation property. According to the invention, the soft magnetic metal powder with the negative thermal expansion coefficient is prepared through a composite reaction, so that the problem of thermal expansion of the powder and a product can be reduced, and meanwhile, a coating insulating layer is better formed on the surface of the powder, so that the insulating property of the powder is greatly improved.)

1. A preparation method of soft magnetic metal powder with negative thermal expansion coefficient and high insulation characteristic is characterized by comprising the following steps:

carrying out vacuum heat treatment on the soft magnetic metal powder;

preparing 0.5-1% by mass of nano zirconium hydroxide solution, 0.5-1% by mass of nano aluminum tungstate solution, 0.5-2% by mass of aluminum dihydrogen phosphate solution and analytically pure phosphoric acid liquid;

uniformly mixing three solutions of nano zirconium hydroxide, nano aluminum tungstate and aluminum dihydrogen phosphate, adding phosphoric acid for titration, and adjusting the pH value of the solution to 3-4 to obtain a mixed solution;

adding the soft magnetic metal powder subjected to vacuum heat treatment into the mixed solution, performing ultrasonic treatment for 45-90 minutes, heating to 110 ℃, and mechanically stirring while heating until reactants are completely dried, and stopping heating and stirring to obtain a soft magnetic metal powder preform with a negative thermal expansion coefficient and high insulation property;

and carrying out atmosphere protection heat treatment on the soft magnetic metal powder preform with the negative thermal expansion coefficient and the high insulation characteristic at the temperature of 500-650 ℃ for 3-6 hours, and cooling to room temperature to obtain the soft magnetic metal powder with the negative thermal expansion coefficient and the high insulation characteristic.

2. The method for producing a soft magnetic metal powder having a negative thermal expansion coefficient and high insulating properties as claimed in claim 1, wherein the vacuum heat treatment is carried out under conditions of 800 to 1000 ℃ and a degree of vacuum of 4 × 10^-3Pa, temperature control precision +/-0.1 ℃.

3. A method for preparing a soft magnetic metal powder with negative thermal expansion coefficient and high insulation characteristics as claimed in claim 1 or 2, wherein a magnetic field is added while the soft magnetic metal powder is subjected to heat treatment, and the magnetic field strength is 0-4 kA/m.

4. A method for preparing soft magnetic metal powder with negative thermal expansion coefficient and high insulation property according to claim 3, wherein the mass ratio of the nano zirconium hydroxide, the nano aluminum tungstate and the nano aluminum dihydrogen phosphate is (3-5): (2-8): (1-5).

5. A method for producing a soft magnetic metal powder with a negative thermal expansion coefficient and high insulation property as claimed in claim 4, wherein the mass of the soft magnetic metal powder is 3 to 5 times the mass of the mixed solution.

6. A method for preparing soft magnetic metal powder with negative thermal expansion coefficient and high insulation property according to claim 5, wherein the nano zirconium hydroxide solution is nano zirconium hydroxide ethanol solution, the nano aluminum tungstate solution is nano aluminum tungstate ethanol solution, and the aluminum dihydrogen phosphate solution is aluminum dihydrogen phosphate distilled water solution.

7. A method for preparing a soft magnetic metal powder having a negative thermal expansion coefficient and high insulating property as claimed in claim 1, wherein the atmosphere is any one of helium, neon, argon, krypton, xenon or nitrogen.

8. A method for preparing soft magnetic metal powder with negative thermal expansion coefficient and high insulation property as claimed in claim 1, wherein the soft magnetic metal powder is one or more of carbonyl iron powder, ferrosilicon alloy powder, ferrosilicon chromium alloy powder and ferrosilicon aluminum alloy powder.

9. A method for preparing a soft magnetic metal powder with negative thermal expansion coefficient and high insulating property as claimed in claim 1, wherein the stirring speed during the mechanical stirring while heating is 30 to 50 rad/s.

10. A soft magnetic metal powder having a negative thermal expansion coefficient and high insulation characteristics, which is obtained by the production method according to any one of claims 1 to 9.

Technical Field

The invention belongs to the field of magnetic functional materials, and particularly relates to soft magnetic metal powder with negative thermal expansion coefficient and high insulation property and a preparation method thereof.

Background

The magnetic material is widely applied to electronic and electric products and is one of basic materials in the material industry. It has special functions of energy conversion, storage and the like. Compared with the traditional laminated rigid magnetic core, the soft magnetic composite material obtained by coating the insulating film on the surface of the ferromagnetic particles has a series of unique properties, such as three-dimensional isotropic magnetic property, extremely low eddy current loss, flexible magnetic core structure design and the like, and the soft magnetic composite material has wide application prospect due to the characteristics. However, electronic products made of soft magnetic materials are subjected to high temperature impact of 250 +/-5 ℃ in the process of being welded on PCB plates, in the process of rapidly increasing the temperature, the danger of cracking of the product is caused due to the thermal expansion characteristics of the powder and the coating film, and a great deal of research is carried out at home and abroad to solve the problem, for example, the epoxy adhesive for the integrated molding technology of electronic components and the preparation method thereof with the publication number of CN103555246A invents an adhesive formula with higher body strength, high modulus, high Tg and high bonding strength than the traditional adhesive, the adhesive for the integrated molding of electronic components and the preparation method thereof with the publication number of CN107674625A also develops a new adhesive formula with high strength, however, these methods only place the center of gravity to improve the strength of the adhesive, and do not consider the essential problem of thermal expansion of the material.

Disclosure of Invention

Aiming at the problems, the invention provides soft magnetic metal powder with negative thermal expansion coefficient and high insulation property and a preparation method thereof, and aims to solve the problems that the soft magnetic metal powder prepared by the existing soft magnetic metal powder preparation method is easy to expand when heated, is easy to cause product cracking, and is poor in powder coating effect and insulation property.

A preparation method of soft magnetic metal powder with negative thermal expansion coefficient and high insulation property comprises the following steps:

carrying out vacuum heat treatment on the soft magnetic metal powder;

preparing 0.5-1% by mass of nano zirconium hydroxide solution, 0.5-1% by mass of nano aluminum tungstate solution, 0.5-2% by mass of aluminum dihydrogen phosphate solution and analytically pure phosphoric acid liquid;

uniformly mixing three solutions of nano zirconium hydroxide, nano aluminum tungstate and aluminum dihydrogen phosphate, adding phosphoric acid for titration, and adjusting the pH value of the solution to 3-4 to obtain a mixed solution;

adding the soft magnetic metal powder subjected to vacuum heat treatment into the mixed solution, performing ultrasonic treatment for 45-90 minutes, heating to 110 ℃, and mechanically stirring while heating until reactants are completely dried, and stopping heating and stirring to obtain a soft magnetic metal powder preform with a negative thermal expansion coefficient and high insulation property;

and carrying out atmosphere protection heat treatment on the soft magnetic metal powder preform with the negative thermal expansion coefficient and the high insulation characteristic at the temperature of 500-650 ℃ for 3-6 hours, and cooling to room temperature to obtain the soft magnetic metal powder with the negative thermal expansion coefficient and the high insulation characteristic.

The product obtained after mixing and reacting several substances such as nano zirconium hydroxide, nano aluminum tungstate, aluminum dihydrogen phosphate and the like has a negative thermal expansion coefficient, and the mass fraction of each material is controlled to be 0.5-2.0% because the coating effect is not ideal due to too little addition, and the magnetic conductivity of the powder is reduced due to too much addition, so that the magnetic property requirement cannot be met.

Furthermore, the heat treatment conditions are 800-1000 ℃, the vacuum degree is 4 multiplied by 10 < -3 > Pa, and the temperature control precision is +/-0.1 ℃.

Furthermore, a magnetic field is added while the soft magnetic metal powder is subjected to heat treatment, and the magnetic field intensity is 0-4 kA/m.

Furthermore, the mass ratio of the nano zirconium hydroxide, the nano aluminum tungstate and the aluminum dihydrogen phosphate is (3-5): (2-8): (1-5).

Controlling the mass ratio of the nano zirconium hydroxide, the nano aluminum tungstate and the aluminum dihydrogen phosphate to be (3-5): (2-8): (1-5), the effect of the whole reaction system can be optimal, the reaction is more complete, and the reaction residual materials are less, so that the aims of saving the cost and efficiently producing are fulfilled.

Further, the mass of the soft magnetic metal powder is 3 to 5 times the mass of the mixed solution.

In actual operation, if the amount of the mixed solution is too much, the waste of liquid and the difficulty of subsequent drying can be caused; if the amount of the mixed solution is too small, it may be difficult to sufficiently contact the powder with the solution, and uniform coating may not be achieved. The quality of the soft magnetic metal powder is controlled to be 3-5 times of the quality of the mixed solution, and meanwhile, the soft magnetic metal powder can be in more uniform contact with the substances in the mixed solution by matching with the ultrasonic treatment mode in the invention, so that the optimal coating effect is achieved.

Furthermore, the nano zirconium hydroxide solution is a nano zirconium hydroxide ethanol solution, the nano aluminum tungstate solution is a nano aluminum tungstate ethanol solution, and the aluminum dihydrogen phosphate solution is a distilled aluminum dihydrogen phosphate aqueous solution.

Further, the atmosphere is any one of helium, neon, argon, krypton, xenon, or nitrogen.

Furthermore, the soft magnetic metal powder is one or more of carbonyl iron powder, ferrosilicon-chromium alloy powder and ferrosilicon-aluminum alloy powder.

Further, the stirring speed during the mechanical stirring while heating is 30 to 50 rad/s.

The invention also provides soft magnetic metal powder with negative thermal expansion coefficient and high insulation property, which is prepared by the preparation method.

According to the soft magnetic metal powder with the negative thermal expansion coefficient and the high insulation characteristic and the preparation method thereof, disclosed by the invention, the soft magnetic metal powder with the negative thermal expansion coefficient is prepared through a composite reaction, so that the problem of thermal expansion of the powder and a product can be successfully reduced, meanwhile, an insulating layer is better coated on the surface of the powder, the insulation characteristic of the powder is greatly improved, and the preparation method is simple to operate and is suitable for industrial production. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic view showing a process for preparing a soft magnetic metal powder having a negative thermal expansion coefficient and high insulation property according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. 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 fig. 1, fig. 1 is a schematic view showing a process for preparing a soft magnetic metal powder having a negative thermal expansion coefficient and high insulation property according to the present invention. As shown in fig. 1, the method for preparing the soft magnetic metal powder having the negative thermal expansion coefficient and the high insulation property includes the steps of:

carrying out vacuum heat treatment on the soft magnetic metal powder, wherein the heat treatment condition is 800-1000 ℃, and the vacuum degree is 4 × 10^-3Pa, temperature control precision is +/-0.1 ℃; adding a magnetic field while carrying out heat treatment on the soft magnetic metal powder, wherein the magnetic field intensity is 0-4 kA/m.

Preparing 0.5-1% by mass of nano zirconium hydroxide solution, 0.5-1% by mass of nano aluminum tungstate solution, 0.5-2% by mass of aluminum dihydrogen phosphate solution and analytically pure phosphoric acid liquid;

wherein the nano zirconium hydroxide solution is a nano zirconium hydroxide ethanol solution, the nano aluminum tungstate solution is a nano aluminum tungstate solution ethanol solution, and the aluminum dihydrogen phosphate solution is a distilled aluminum dihydrogen phosphate aqueous solution;

uniformly mixing three solutions of nano zirconium hydroxide, nano aluminum tungstate and aluminum dihydrogen phosphate, adding phosphoric acid for titration, and adjusting the pH value of the solution to 3-4 to obtain a mixed solution, wherein the mass ratio of the nano zirconium hydroxide to the nano aluminum tungstate to the aluminum dihydrogen phosphate is (3-5): (2-8): (1-5);

adding the heat-treated soft magnetic metal powder into the mixed solution, wherein the mass of the soft magnetic metal powder is 3-5 times of that of the mixed solution, performing ultrasonic treatment for 45-90 minutes, heating to 110 ℃, heating while performing mechanical stirring at a stirring speed of 30-50rad/s, and stopping heating and stirring until reactants are completely dried to obtain a soft magnetic metal powder preform with a negative thermal expansion coefficient and high insulation property;

and carrying out atmosphere protection heat treatment on the soft magnetic metal powder preform with the negative thermal expansion coefficient and the high insulation characteristic at the temperature of 500-650 ℃ for 3-6 hours, and cooling to room temperature to obtain the soft magnetic metal powder with the negative thermal expansion coefficient and the high insulation characteristic.

Wherein the atmosphere includes, but is not limited to, helium, neon, argon, krypton, xenon, or nitrogen.

The soft magnetic metal powder with negative thermal expansion coefficient and high insulation property is prepared by the preparation method, and the performance of the soft magnetic metal powder is detected.