阅读说明：本技术 一种具有MnO-SiO2复合绝缘层的铁硅软磁复合粉末及其制备方法 (Has MnO-SiO2Iron-silicon soft magnetic composite powder of composite insulating layer and preparation method thereof ) 是由 樊希安 罗自贵 杨振甲 于 2020-12-22 设计创作，主要内容包括：本发明属于软磁粉芯技术领域,具体涉及一种具有MnO-SiO-2复合绝缘层的铁硅软磁复合粉末及其制备方法,其步骤为1.将纳米锰氧化物粉末与铁硅合金粉末按质量比1∶9～99进行混合,将混合后的粉末进行粉磨得到复合粉末；2.将所得复合粉末进行高温烧结得到具有MnO-SiO-2复合绝缘层的铁硅软磁复合粉末。本发明所提供铁硅软磁复合粉末具有稳定性好、耐高温、电阻特性优良且饱和磁化强度高的特性；此外该工艺简单且生产成本低,具有良好的应用前景。(The invention belongs to the technical field of soft magnetic powder cores, and particularly relates to a soft magnetic powder core with MnO-SiO 2 The preparation method comprises the following steps of 1, mixing nano manganese oxide powder and iron-silicon alloy powder according to the mass ratio of 1: 9-99, and grinding the mixed powder to obtain composite powder; 2. sintering the obtained composite powder at high temperature to obtain the powder with MnO-SiO 2 Iron-silicon soft magnetic composite powder of the composite insulating layer. The iron-silicon soft magnetic composite powder provided by the invention has the characteristics of good stability, high temperature resistance, excellent resistance characteristic and high saturation magnetization intensity; in addition, the process is simple, the production cost is low, and the method has a good application prospect.)

1. Has MnO-SiO₂The preparation method of the iron-silicon soft magnetic composite powder of the composite insulating layer is characterized by comprising the following steps:

firstly, mixing nano manganese oxide powder and iron-silicon alloy powder according to the mass ratio of 1: 9-99, and grinding the mixed powder to obtain composite powder;

secondly, sintering the obtained composite powder at high temperature to obtain the powder with MnO-SiO₂Iron-silicon soft magnetic composite powder of the composite insulating layer.

2. The composition of claim 1, wherein said composition has MnO-SiO₂The preparation method of the iron-silicon soft magnetic composite powder of the composite insulating layer is characterized by comprising the following steps of: the nano manganese oxide powder in the first step is composed of MnO₂、Mn₂O₃And Mn₃O₄One or more of them, and the average particle diameter is 1 to 100 nm.

3. The composition of claim 1, wherein said composition has MnO-SiO₂The preparation method of the iron-silicon soft magnetic composite powder of the composite insulating layer is characterized by comprising the following steps of: in the first step, the silicon content of the ferrosilicon alloy powder is 1.5-13.5% by mass, and the grain diameter of the ferrosilicon alloy powder is 10-200 μm.

4. The composition of claim 1, wherein said composition has MnO-SiO₂The preparation method of the iron-silicon soft magnetic composite powder of the composite insulating layer is characterized by comprising the following steps of: the powder grinding is to mix the mixed powder and agate balls according to the mass ratio of 1: 10-20, put the mixture into the same ball milling tank, perform ball milling for 15-30 hours under the condition of 100-300 revolutions per minute, and separate the agate balls after the powder grinding is finishedAnd (4) removing.

5. The composition of claim 1, wherein said composition has MnO-SiO₂The preparation method of the iron-silicon soft magnetic composite powder of the composite insulating layer is characterized by comprising the following steps of: and in the second step, the high-temperature sintering is to place the composite powder into a mold and place the mold in a high-temperature sintering furnace, heat the composite powder to 800-1000 ℃ under the protective atmosphere, preserve heat for 0.5-5 h, and cool the composite powder along with the furnace.

6. The composition of claim 5, wherein said composition has MnO-SiO₂The preparation method of the iron-silicon soft magnetic composite powder of the composite insulating layer is characterized by comprising the following steps of: the protective atmosphere is nitrogen or argon.

7. Has MnO-SiO₂The iron-silicon soft magnetic composite powder of the composite insulating layer is characterized in that: said has MnO-SiO₂The iron-silicon soft magnetic composite powder of the composite insulating layer is one having MnO-SiO according to any one of claims 1 to 6₂The iron-silicon soft magnetic composite powder of the composite insulating layer is prepared by the preparation method.

Technical Field

The invention belongs to the technical field of soft magnetic powder cores. In particular to a material with MnO-SiO₂Iron-silicon soft magnetic composite powder of a composite insulating layer and a preparation method thereof.

Background

The soft magnetic powder core is used as an indispensable magnetic element of a power circuit due to high magnetic conductivity, low loss, low magnetostriction, excellent thermal stability and direct current bias capability, is widely applied to electronic components such as inverters, inductors, transformers, chokes and the like, and relates to the fields of motors, telecommunication, power supplies and the like.

The eddy current loss of the soft magnetic powder core increases exponentially as the frequency of use increases, and the insulation coating of the soft magnetic composite powder is undoubtedly the most effective method for reducing the eddy current loss. On the basis, the insulation coating is mainly divided into an organic coating and an inorganic coating. The traditional organic coating materials such as phenolic resin, epoxy resin and the like have poor heat resistance, and cannot be subjected to high-temperature heat treatment at the temperature of more than 200 ℃ and eliminate high-temperature residual stress, so that the magnetic performance is influenced. And the soft magnetic powder core coated by the organic material generates heat due to eddy current loss in long-term operation, so that the organic insulating layer is aged and even thermally decomposed, the insulativity of the soft magnetic powder core is weakened, the eddy current loss is increased, and the stability of the soft magnetic powder core is influenced. Therefore, the inorganic coating material is receiving attention for its excellent chemical and thermal stability and electrical insulation.

The common inorganic coating material for soft magnetic powder core mainly comprises Al₂O₃MgO and SiO₂However, the ceramic materials are brittle phases, and effective insulation coating is difficult to achieve by using a ball milling process, which deteriorates the soft magnetic property and the insulation property of the soft magnetic composite powder, so that it is very important to prepare an insulating layer capable of achieving both excellent soft magnetic property and low loss of the soft magnetic powder core.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides the soft magnetic composite powder with simple process, low production cost, excellent resistance characteristic and high saturation magnetization. The invention adopts the technical scheme that the material has MnO-SiO₂The preparation method of the iron-silicon soft magnetic composite powder of the composite insulating layer is characterized by comprising the following steps:

firstly, mixing nano manganese oxide powder and iron-silicon alloy powder according to the mass ratio of 1: 9-99, and grinding the mixed powder to obtain composite powder;

secondly, sintering the obtained composite powder at high temperature to obtain the powder with MnO-SiO₂Iron-silicon soft magnetic composite powder of the composite insulating layer.

And, the nano-manganese oxide powder in the first step is composed of MnO₂、Mn₂O₃And Mn₃O₄One or more of them, and the average particle diameter is 1 to 100 nm.

In addition, in the first step, the mass percentage of silicon contained in the ferrosilicon alloy powder is 1.5-13.5%, and the particle size of the ferrosilicon alloy powder is 10-200 μm.

And in the second step, the high-temperature sintering is to place the composite powder into a mold and place the mold in a high-temperature sintering furnace, heat the composite powder to 800-1000 ℃ under the protective atmosphere, preserve the heat for 0.5-5 h, and cool the composite powder along with the furnace.

Moreover, the protective atmosphere is nitrogen or argon.

Has MnO-SiO₂Iron-silicon soft magnetic composite powder of composite insulating layer, made of any one of the above with MnO-SiO₂The iron-silicon soft magnetic composite powder of the composite insulating layer is prepared by the preparation method.

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

(1) mixing nanoscale manganese oxide and micron-sized iron-silicon alloy powder, performing ball milling to obtain iron-silicon-based composite powder with a manganese oxide coating layer, performing high-temperature sintering process, and performing redox reaction on Si in the alloy and the manganese oxide coating layer under high-temperature condition to generate high-resistance MnO-SiO₂A composite insulating layer is formed, namely the composite insulating layer with MnO-SiO₂Iron-silicon soft magnetic composite powder of the composite insulating layer. The invention adopts ball milling and high-temperature sintering processes which are simple and easy to operate, so that the preparation cost is low, the process is simple and easy, the repeatability is good, and the application prospect is good.

(2) The invention utilizes the good flexibility and adsorption property of the nano manganese oxide and the good toughness of the agate balls, thereby realizing the highly uniform coating of the nano manganese oxide on the iron-silicon alloy powder through long-time ball milling, and further forming highly insulated MnO-SiO₂And (4) compounding a coating layer. And ceramic oxides such as SiO with good insulation₂And Al₂O₃And the like, because of their brittleness and poor interfacial adhesion, the insulating coating of ferrosilicon powder cannot be achieved by the same process. Therefore, the iron-silicon soft magnetic composite powder prepared by the inventionThe powder has highly uniform MnO-SiO₂The composite insulating layer does not introduce redundant non-magnetic phases, so that the resistance characteristic is excellent and the saturation magnetization is high.

(3) The preparation method of the invention realizes the orientation of the low-resistance manganese oxide coating layer to the high-insulation MnO-SiO by using a high-temperature sintering process₂The iron-silicon soft magnetic composite powder prepared by the transformation of the composite coating layer has excellent chemical stability and remarkable high temperature resistance.

Therefore, the invention has simple process and low production cost, and the prepared MnO-SiO₂The iron-silicon soft magnetic composite powder of the composite insulating layer has good stability, high temperature resistance, excellent resistance characteristic and high saturation magnetization.

Drawings

FIG. 1 is an XRD pattern of a composite powder prepared in example 1 of the present invention measured before and after high temperature sintering;

FIG. 2 is an XRD pattern of the powder of example 2 of the present invention after a first ball milling step;

FIG. 3 is an XRD pattern of the powder of example 2 of the present invention after a second high temperature sintering step.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and examples, and the present invention is not limited to the examples.

Example 1

Has MnO-SiO₂The preparation method of the iron-silicon soft magnetic composite powder of the composite insulating layer comprises the following steps:

first step, composite powder preparation

Mixing nano manganese oxide powder with the average particle size of 1nm and iron-silicon alloy powder (wherein the content of Si in the iron-silicon alloy powder is 1.5 wt%, the balance is iron, and the particle size of the iron-silicon alloy powder is 10 mu m) according to the mass ratio of 1: 20, placing the mixed powder and agate balls in the same ball-milling tank according to the mass ratio of 1: 10, carrying out ball milling for 15 hours under the condition of 100 revolutions per minute, separating the agate balls to obtain FeSi alloy and manganese metal oxide composite powder, namely FeSi/manganese oxide composite powder, wherein an XRD (X-ray diffraction) pattern measured before high-temperature sintering of the powder is shown as a line close to the lower part in figure 1;

second step, high temperature sintering

Putting the composite powder into a mold, placing the mold in a high-temperature sintering furnace, heating to 800 ℃ under the protective atmosphere condition, preserving heat for 0.5h, and cooling along with the furnace to obtain the composite powder with MnO-SiO₂The iron-silicon soft magnetic composite powder of the composite insulating layer has an XRD pattern as shown by the upper line in FIG. 1 after high-temperature sintering.

Wherein the nano manganese oxide powder consists of MnO₂、Mn₂O₃And Mn₃O₄One or more of the above.

Wherein the protective atmosphere is nitrogen or argon.

Example 2

First step, composite powder preparation

Mixing nano manganese oxide powder with the average particle size of 70nm and iron-silicon alloy powder (wherein the Si content of the iron-silicon alloy powder is 9.5 wt%, the balance is iron, and the particle size of the iron-silicon alloy powder is 150 mu m) according to the mass ratio of 1: 9, placing the mixed powder and agate balls in the same ball-milling tank according to the mass ratio of 1: 20, carrying out ball milling for 30h under the condition of 300 revolutions per minute, and separating the agate balls to obtain composite powder;

second step, high temperature sintering

Putting the composite powder into a mold, placing the mold in a high-temperature sintering furnace, heating to 900 ℃ under the protective atmosphere condition, preserving heat for 5 hours, and cooling along with the furnace to obtain the composite powder with MnO-SiO₂Iron-silicon soft magnetic composite powder of the composite insulating layer.

FIG. 2 is an XRD pattern after a first ball milling step; FIG. 3 is an XRD pattern after a second high temperature sintering step.

Wherein the nano manganese oxide powder consists of MnO₂、Mn₂O₃And Mn₃O₄One or more of the above.

Wherein the protective atmosphere is nitrogen or argon.

Example 3

First step, composite powder preparation

Mixing nano manganese oxide powder with the average particle size of 50nm and iron-silicon alloy powder (wherein the Si content of the iron-silicon alloy powder is 15 wt%, the balance is iron, and the particle size of the iron-silicon alloy powder is 20 mu m) according to the mass ratio of 1: 99, placing the mixed powder and agate balls in the same ball-milling tank according to the mass ratio of 1: 10, carrying out ball milling for 25 hours under the condition of 300 revolutions per minute, and separating the agate balls to obtain composite powder;

second step, high temperature sintering

Putting the composite powder into a mold, placing the mold in a high-temperature sintering furnace, heating to 800 ℃ under the protective atmosphere condition, preserving heat for 1.5h, and cooling along with the furnace to obtain the composite powder with MnO-SiO₂Iron-silicon soft magnetic composite powder of the composite insulating layer.

Wherein the nano manganese oxide powder consists of MnO₂、Mn₂O₃And Mn₃O₄One or more of the above.

Wherein the protective atmosphere is nitrogen or argon.

Example 4

Mixing nano manganese oxide powder with the average particle size of 100nm and iron-silicon alloy powder (wherein the Si content of the iron-silicon alloy powder is 11 wt%, the balance is iron, and the particle size of the iron-silicon alloy powder is 200 mu m) according to the mass ratio of 1: 50, placing the mixed powder and agate balls in the same ball-milling tank according to the mass ratio of 1: 20, carrying out ball milling for 20 hours under the condition of 300 revolutions per minute, and separating the agate balls to obtain composite powder;

second step, high temperature sintering

Putting the composite powder into a mold, placing the mold in a high-temperature sintering furnace, heating to 1000 ℃ under the protective atmosphere condition, preserving heat for 3 hours, and cooling along with the furnace to obtain the composite powder with MnO-SiO₂Iron-silicon soft magnetic composite powder of the composite insulating layer.

Wherein the nano manganese oxide powder consists of MnO₂、Mn₂O₃And Mn₃O₄One or more of the above.

Wherein the protective atmosphere is nitrogen or argon.

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

1. obtain a material with MnO-SiO₂The iron-silicon soft magnetic composite powder of the composite insulating layer has the characteristics of good stability, high temperature resistance, excellent resistance and high saturation magnetization; 2. the manufacturing process is simple, the production cost is low, and the application prospect is good.