CN114927304A - Powder for inductor, preparation method thereof and integrally-formed inductor - Google Patents

Abstract

The application discloses powder for an inductor, a preparation method thereof and an integrally formed inductor, relating to the technical field of inductors; the feed comprises the following raw materials in parts by weight: 90-97 parts of soft magnetic powder; 1-3 parts of a reinforcing agent; 0.25-0.4 part of passivator; 0.3-0.5 part of binder; the soft magnetic powder consists of carbonyl iron powder and iron-silicon-chromium powder; the reinforcing agent consists of cobalt oxide, nickel iron powder, iron-silicon-aluminum powder and FeSiNbCuB crystal powder; the application provides a technical scheme has promoted inductance core's rerum natura, makes it have more excellent magnetic conductivity performance simultaneously.

Description

Powder for inductor, preparation method thereof and integrally-formed inductor

Technical Field

The application relates to the technical field of inductors, in particular to powder for an inductor and an integrally formed inductor.

Background

The integrally formed inductor has been widely used due to its advantages of miniaturization, strong anti-electromagnetic interference performance, low noise, high frequency, etc. The integrally formed inductor is mainly composed of a metal soft magnetic composite material and a metal copper coil, and is generally prepared by embedding a coil winding into metal soft magnetic powder through a powder metallurgy process and then curing an adhesive through baking.

However, the traditional alloy soft magnetic material has low resistivity, large eddy current under high frequency and serious heating, thereby limiting the use of the traditional alloy soft magnetic material under high frequency; in addition, under the condition that the traditional inductor is kept in a severe use environment for a long time, because the oxide powder wraps more gaps after the soft metal magnetic powder is baked, the density of the inductor material is influenced, the strength of the inductor material is finally influenced, and the electric indexes such as magnetic conductivity and the like are influenced.

Disclosure of Invention

The application aims to provide inductance powder, a preparation method thereof and an integrally formed inductor, and in a first aspect, the application provides the inductance powder which comprises the following raw materials in parts by weight:

90-95 parts of soft magnetic powder;

1-3 parts of a reinforcing agent;

0.1-0.25 parts of passivator;

0.3-0.5 part of binder;

the soft magnetic powder consists of carbonyl iron powder and iron-silicon-chromium powder;

the reinforcing agent consists of cobalt oxide, nickel iron powder, iron-silicon-aluminum powder and FeSiNbCuB crystal powder.

Preferably, the reinforcing agent comprises the following components in percentage by mass: 10-20% of cobalt oxide, 25-30% of nickel, 25-35% of aluminum and the balance of FeSiNbCuB nanocrystalline powder.

Preferably, the binder comprises the following raw materials in parts by weight:

55-65 parts of organic silicon resin;

5-10 parts of epoxy silane coupling agent;

a film-forming agent; 3-5 parts;

a curing agent; 5-10 parts.

Preferably, the silicone resin is a methyl polysiloxane resin.

Preferably, the epoxy silane coupling agent is one of gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, and gamma-glycidoxypropyltripropoxysilane.

Preferably, the film forming agent is tripropylene glycol n-butyl ether; the curing agent is an epoxy curing agent; the lubricant is one of stearic acid and paraffin micro powder.

In a second aspect, the present application provides a method for preparing a powder for an inductor, comprising the steps of:

s1, weighing the raw materials in proportion, and screening the soft magnetic powder; mixing passivators, dividing into two parts, adding the screened soft magnetic powder into one part of passivators, mixing, stirring, baking and cooling to room temperature to obtain first powder;

s2, weighing the components in the reinforcing agent according to the proportion, mixing, fully mixing and screening; adding the screened reinforcing agent into the other part of passivator, stirring, baking and cooling to room temperature to obtain second powder;

s3, adding the components of the binder into an acetone solution, and preparing the binder solution; and mixing the first powder and the second powder, adding the mixture into the binder solution, fully mixing, heating to remove the organic solvent, and drying to obtain the target product.

Preferably, the soft magnetic powder has a sieve size distribution of D10 ═ 2 to 6 μm, D50 ═ 6 to 8 μm, and D90 ═ 10 to 15 μm;

the sieve particle size distribution of the reinforcing agent is D10-4-6 μm, D50-8-12 μm and D90-15-20 μm.

In a third aspect, the present application provides an integrally molded inductor comprising the powder for an inductor as described in any of the above.

In a fourth aspect, the present application provides a method for preparing an integrally formed inductor, based on any of the above methods for preparing inductor powder; the method comprises the following steps:

after step S2, adding the components of the binder into an acetone solution, and blending the binder solution; mixing the first powder and the second powder, adding the mixture into a binder solution, and fully mixing to obtain a compound; embedding the conductor into the compound, and baking and curing;

the baking and curing step comprises a first stage and a second stage;

the first baking temperature of the first stage is 60-100 ℃, the heating rate is 3-5 ℃/min, and the constant temperature is 30-60min after the first baking temperature is reached;

the second baking temperature of the second stage is 100-.

Compared with the prior art, the beneficial effect of this application lies in:

1. in the invention, the research finds that the physical characteristics of the finally formed inductor, such as the pressing density of the finally formed inductor, can be effectively improved by adding the reinforcing agent of which the main components are cobalt oxide and FeSiNbCuB crystal powder; the primary analysis shows that soft magnetic powder consisting of carbonyl iron powder and iron-silicon-chromium powder is used as a main substrate, the characteristics of easy compression molding and small particle size are utilized, a reinforcing agent with the main components of cobalt oxide and FeSiNbCuB crystal powder is added subsequently, the cobalt oxide and the FeSiNbCuB crystal powder are matched to optimize the internal structure, and the final integrally compression molded inductor has more excellent physical strength;

2. cobalt oxide is selected to be matched with FeSiNbCuB crystal powder, and a proper proportion is selected, so that the magnetic permeability of the inductor is effectively improved while the internal molecular structure of the inductor is optimized;

3. the scheme is further matched with the characteristics of the thermosetting resin, a sectional heating mode is adopted, so that the first powder and the second powder can be fully bonded into a whole to form a compact molecular structure, the strength of the integrally formed inductor is effectively improved, and the cracking rate is effectively reduced.

4. In the invention, researches show that the final film forming effect is improved by adding the gamma-glycidoxypropyltrimethoxysilane as the epoxy silane coupling agent and matching the gamma-glycidoxypropyltrimethoxysilane with the film forming agent, and the cracking rate is further effectively reduced.

5. The high-temperature resistance of the magnetic core is fully considered by selecting the organic silicon resin and the epoxy silane coupling agent, so that the stability of the magnetic core is kept, the stress difference inside and outside the magnetic core is reduced, the surface and internal cracks of the magnetic core are reduced, the performance stability of the magnetic core is further improved, and the service life of the magnetic core is further prolonged.

6. The soft magnetic powder and the reinforcing agent are processed after being screened, and gaps among large particles are filled by small particles by controlling the proportion of different particle size particles, so that the size of gaps among powder particles can be effectively reduced, the density of the powder particles is improved, and the magnetic conductivity of the magnetic core is improved.

Detailed Description

The present invention will now be described in detail with reference to the following examples, in order to make the objects, features and advantages of the present invention more comprehensible. Several embodiments of the invention are given below. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete:

in the present invention, all the raw materials are commercially available or commonly used in the art, and the methods in the following examples are conventional in the art unless otherwise specified.

Example 1

S1, according to 1: 1, mixing carbonyl iron powder and iron-silicon-chromium powder, and sieving 2.85kg of mixed powder;

preparing a passivating agent, namely an acetone phosphate solution, and dividing the solution into two parts; adding the screened soft magnetic powder into one part of passivator, mixing and stirring for 20-30min, baking at 110 ℃ for 20min, and cooling to room temperature to obtain first powder;

s2, blending the reinforcing agent according to the proportion in the table 2, weighing the reinforcing agent according to the proportion, adding the weighed reinforcing agent into the rest passivating agent, mixing and stirring for 20-30min, baking for 20min at 120 ℃, and cooling to room temperature to obtain two powders;

s3, preparing a binder according to the mixture ratio in the table 3, adding each component of the binder into an acetone solution, and preparing the binder solution; mixing the first powder and the second powder, adding the mixture into a binder solution, and fully mixing to obtain a compound; burying the conductor in the compound, pressing and molding, and baking and curing;

wherein the baking and curing step comprises a first stage and a second stage;

the first baking temperature of the first stage is 80 ℃, the heating rate is 4 ℃/min, and the constant temperature is kept for 40min after the temperature reaches 80 ℃;

the second baking temperature of the second stage is 120 ℃, the heating rate is 4 ℃/min, and the temperature is kept for 40min after the temperature reaches 120 ℃.

Comparative example 1

The FeSiNbCuB crystal powder was removed, and the cobalt oxide content was increased, the remainder being the same as in example 1.

Comparative example 2

The cobalt oxide is removed, the content of FeSiNbCuB crystal powder is increased, and the rest is the same as that in the embodiment 1.

Example 2

The mass of the mixed powder of carbonyl iron powder and iron-silicon-chromium powder in step S1 in example 1 was 2.70g, and the content of the reinforcing agent was adjusted, and the rest was the same as in example 1.

Example 3

The mass of the mixed powder of carbonyl iron powder and iron-silicon-chromium powder in step S1 in example 1 was selected to be 2.91g, and the content of the reinforcing agent was adjusted, the rest being the same as in example 1.

Comparative example 3

The epoxy silane coupling agent of example 1 was removed and the rest was identical to example 1.

Example 4

The first baking temperature in step S3 in example 1 was adjusted to 100 ℃, the second baking temperature was adjusted to 150 ℃, and the rest was the same as in example 1.

Example 5

The first baking temperature in step S3 in example 1 was adjusted to 60 ℃, the second baking temperature was adjusted to 100 ℃, and the rest was the same as example 1.

Comparative example 4

The baking and curing of step S3 in example 1 was carried out by a single stage heating method, with a heating rate of 4 ℃/min, directly heating to 120 ℃, and the baking time being equal to the sum of the two baking times in example 1.

The integrally formed inductors prepared in examples 1 to 5 and comparative examples 1 to 4 were subjected to a performance test by the following method:

(1) and (3) testing the density: measuring the volume and the weight of the magnetic core, and calculating the density (g/cm3) of the magnetic core;

(2) cracking defect rate: if the magnetic sheet has the cracking condition, marking the cracking defect, and weighing the mass of the magnetic sheet with the cracking defect; the cracking defect rate is the mass of the magnetic sheet with cracking defect/total mass of the magnetic sheet multiplied by 100%;

(3) and (3) magnetic permeability test: the test conditions were 1MHz & 0.25V.

For the specific detection results, see table 4.

Wherein, table 1 is a proportioning table of the inductance powder of each example and comparative example; table 2 shows the compounding ratio of the reinforcing agents of each example and comparative example; table 3 is a table of the compounding ratios of the binders of the respective examples and comparative examples; table 4 shows the results of the respective testing indexes of the examples and comparative examples.

The results of the comprehensive examination can be obtained, wherein in comparative examples 1-3, it can be seen from the results that the addition amount between the soft magnetic powder and the reinforcing agent has a certain influence on the density of the final inductor core, and the magnetic permeability and the product density of the finally produced magnetic core are influenced by the excessively high or excessively low addition amount of the reinforcing agent.

Comparing example 1 with comparative examples 1-2, it can be seen from the results that the magnetic core density, the product cracking rate and the magnetic permeability of the finally produced magnetic core are affected by adding the FeSiNbCuB crystal powder or the cobalt oxide singly, wherein the magnetic permeability is greatly affected.

In comparison between example 1 and comparative example 3, it can be seen from the results that the addition of the epoxy silane coupling agent is not significant in the effect on the cracking rate of the final product.

Comparing example 1 with comparative example 4, it can be seen from the results that the magnetic core produced by the step-wise temperature rise is higher in density, more excellent in permeability and lower in product cracking rate than the direct temperature rise.

TABLE 1

Group of component	Soft magnetic powder (kg)	Reinforcing agent (g)	Passivating agent (g)	Binder (g)
					Example 1	2.85	60	9	12
Example 2	2.7	90	9	12
					Example 3	2.91	20	9	12
Example 4	2.85	60	9	12
					Example 5	2.85	60	9	12
Comparative example 1	2.85	60	9	12
					Comparative example 2	2.85	60	9	12
Comparative example 3	2.85	60	9	12
					Comparative example 4	2.85	60	9	12

TABLE 2

Components Group of	Cobalt oxide （g）	Iron nickelate powder （g）	Iron siliconAluminium powder （g）	FeSiNbCuB crystal powder （g）
					Example 1	15	30	30	25
Example 2	15	30	30	25
					Example 3	15	30	30	25
Example 4	15	30	30	25
					Example 5	15	30	30	25
Comparative example 1	40	30	30	0
					Comparative example 2	0	30	30	40
Comparative example 3	15	30	30	25
					Comparative example 4	15	30	30	25

TABLE 3

Group of component	Methylpolysiloxane Resin (g)	Gamma-glycidoxypropyl tris (meth) acrylate Methoxysilane (g)	Tripropylene glycol n-butyl ether Butyl ether (g)	Epoxy curing Agent (g)
					Example 1	60	8	4	8
Example 2	60	8	4	8
					Example 3	60	8	4	8
Example 4	60	8	4	8
					Example 5	60	8	4	8
Comparative example 1	60	8	4	8
					Comparative example 2	60	8	4	8
Comparative example 3	60	0	4	8
					Comparative example 4	60	8	4	8

TABLE 4

Index group	Density (g/cm) 3 ）	Crack defect rate (%)	Magnetic permeability
				Example 1	5.76	0.1	32.6
Example 2	5.7	0.3	31.5
				Example 3	5.68	0.3	31.7
Example 4	5.64	0.4	31.1
				Example 5	5.66	0.2	30.6
Comparative example 1	5.43	1.0	26.6
				Comparative example 2	5.46	0.6	26.4
Comparative example 3	5.54	1.1	27.4
				Comparative example 4	5.55	0.7	27.5

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The above description is only for the preferred embodiment of the present application and should not be taken as limiting the present application in any way, and all simple modifications, equivalent changes and modifications made to the above embodiment according to the technical spirit of the present application are intended to be included within the scope of the present application.

Claims (10)

1. A powder for inductors, characterized in that: the feed comprises the following raw materials in parts by weight:

90-97 parts of soft magnetic powder;

1-3 parts of a reinforcing agent;

0.25-0.4 part of passivator;

0.3-0.5 part of binder;

the soft magnetic powder consists of carbonyl iron powder and iron-silicon-chromium powder;

the reinforcing agent consists of cobalt oxide, nickel iron powder, iron-silicon-aluminum powder and FeSiNbCuB crystal powder.

2. The inductive powder of claim 1, wherein: the reinforcing agent comprises the following components in percentage by mass: 10-20% of cobalt oxide, 25-30% of nickel iron powder, 25-35% of iron silicon aluminum powder and the balance of FeSiNbCuB crystal powder.

3. The inductive powder of claim 1, wherein: the adhesive comprises the following raw materials in parts by weight:

55-65 parts of organic silicon resin;

5-10 parts of epoxy silane coupling agent;

a film-forming agent; 3-5 parts;

a curing agent; 5-10 parts.

4. The powder for inductors according to claim 3, wherein: the organic silicon resin is methyl polysiloxane resin.

5. The inductive powder of claim 3, wherein: the epoxy silane coupling agent is one of gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane and gamma-glycidoxypropyltripropoxysilane.

6. The inductive powder of claim 3, wherein: the film forming agent is tripropylene glycol n-butyl ether; the curing agent is an epoxy curing agent.

7. The method for producing a powder for an inductor according to any one of claims 1 to 6, wherein: the method comprises the following steps:

s1, weighing the raw materials in proportion, and screening the soft magnetic powder; mixing passivators, dividing into two parts, adding the screened soft magnetic powder into one part of passivators, mixing, stirring, baking and cooling to room temperature to obtain first powder;

s2, weighing the components in the reinforcing agent according to the proportion, mixing, fully mixing and screening; adding the screened reinforcing agent into the other part of passivator, stirring, baking and cooling to room temperature to obtain second powder;

s3, adding the components of the binder into an acetone solution, and preparing the binder solution; and mixing the first powder and the second powder, adding the mixture into the binder solution, fully mixing, heating to remove the organic solvent, and drying to obtain the target product.

8. The method for producing according to claim 7, characterized in that: the soft magnetic powder has a sieve particle size distribution of D10 ═ 2 to 6 μm, D50 ═ 6 to 8 μm, and D90 ═ 10 to 15 μm;

the sieving particle size distribution of the reinforcing agent is D10-4-6 μm, D50-8-12 μm and D90-15-20 μm.

9. An integrated inductor, characterized in that: an inductive powder comprising the inductive powder of any one of claims 1 to 6.

10. A preparation method of an integrally formed inductor is characterized by comprising the following steps: a method for producing the powder for an inductor according to any one of claims 7 to 8; the method comprises the following steps:

after step S2, adding the components of the binder into an acetone solution, and blending the binder solution; mixing the first powder and the second powder, adding the mixture into a binder solution, and fully mixing to obtain a compound; embedding the conductor into the compound, and baking and curing;

the baking and curing step comprises a first stage and a second stage;

the first baking temperature of the first stage is 60-100 ℃, the heating rate is 3-5 ℃/min, and the constant temperature is 30-60min after the first baking temperature is reached;

the second baking temperature of the second stage is 100-.