EP3281212A1

EP3281212A1 - Soft magnetic composite and corresponding method for producing a soft magnetic composite

Info

Publication number: EP3281212A1
Application number: EP16710976.8A
Authority: EP
Inventors: Alexandra Wilde; Inga Schellenberg; Jens BURGHAUS
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-04-09
Filing date: 2016-03-18
Publication date: 2018-02-14
Also published as: DE102015206326A1; WO2016162188A1; CN107533906A; CN107533906B

Abstract

The invention relates to a soft magnetic composite. Said soft magnetic composite comprises a plurality of crystalline pure iron base particles (E1) and a solid metallic glass (G1), wherein the plurality of crystalline pure iron base particles (E1) have a coating made from the bulk metallic glass (G1) and the plurality of crystalline pure iron base particles (E1) are in contact with each other via the covering made from the bulk metallic glass (G1). The invention also relates to two alternative methods for producing a soft magnetic composite.

Description

Description title

Soft magnetic composite material and corresponding method for producing a soft magnetic composite material.

The present invention provides a soft magnetic composite and corresponding methods of making a soft magnetic

Composite.

State of the art

The publication International Materials Reviews 2013 Vol. 58 No. 3 pages 131 to 166 describes an iron-based solid-metallic glass.

Current soft magnetic composites have good magnetic properties with increased resistance in all three dimensions, which material also has a lack of mechanical stability. Electrical sheets, however, have good mechanical stability, at the same time the resistance is only increased in one dimension. In the present context dimension means a spatial direction, that is, in conventional electric sheets, a magnetic flux is guided in two dimensions (in the plane), with its resistance being orthogonal, that is, directed in the third dimension.

For application in actuators or electrical machine, however, a soft magnetic composite is required, which has a combination of high saturation polarization, low coercive force, high permeability, low eddy current loss and mechanical stability. For such a soft magnetic composite is a broad

Application spectrum ready. Disclosure of the invention

The invention provides a soft magnetic composite material

Claim 1 and corresponding alternative method for producing a soft magnetic composite according to claim 6 and claim 9.

Preferred developments are the subject of the respective subclaims.

Advantages of the invention

The present invention enables a soft magnetic

Composite having a combination of high saturation polarization, low coercivity, high permeability, low eddy current loss, and mechanical stability.

It is an idea of the invention to provide a soft magnetic composite which combines the characteristics mentioned here and has in all three dimensions. The required properties are in particular high permeability and low coercive field strength with respect to the soft magnetic property, low eddy current loss by a high electrical

Resistance and mechanical stability. The soft magnetic composite described here combines these properties and can preferably be used in applications with high frequencies.

By "soft magnetic" is meant in the present context

Composites with low coercivity and high electrical resistance. This leads to low electrical eddy current losses. The soft magnetic composite material described here is used in particular in

Electric motors and actuators used.

The idea here is to provide a soft magnetic composite having a plurality of crystalline pure iron base particles and a bulk metallic glass (BMG), wherein the plurality of crystalline pure iron base particles include, for example, a continuous and / or homogeneous solid state coating have metallic glass can. This means that the large number of crystalline pure iron base particles, for example indirectly, can be in contact with one another via the coating of the solid-metal glass. In other words, a matrix forms, with spaces between the crystalline ones

Pure iron base particles are filled with the solid-metallic glass. In addition, unlike a conventional soft magnetic composite (SMC), ie without crystalline pure iron-based particles, the soft magnetic composite described here has a higher mechanical strength.

The solid-metallic glass made possible by a surface or

External surface isolation of the crystalline pure iron-based particles, the high electrical resistance to reduce the eddy current loss and the good mechanical stability or robustness, the plurality of crystalline pure iron base particles soft magnetic properties, so the high permeability and low coercivity provides.

According to a preferred embodiment, the soft magnetic

Composite material between 60% and 99% crystalline pure iron-based particles and a proportion of the solid-metallic glass (Gl) is correspondingly between 1% and 40%. The solid-metallic glass is based on an iron or zirconium alloy powder with phosphorus, boron, cobalt and / or niobium, wherein the alloy powder between 70% and 95% iron or zirconium and the proportion of phosphorus, boron, cobalt and / or niobium accordingly between 5% and 30% of the alloy powder. This is an exemplary non-exhaustive list of elements, in particular other elements, for example silicon, nickel, silver and / or chromium correspondingly for the materials described here in question. It is advantageous that by a percentage of the plurality of crystalline

Pure iron base particles the soft magnetic property of

Compound material is determinable, wherein the soft magnetic property of the composite material in particular comprises the high saturation polarization, the low coercivity and the high permeability. According to a further preferred development, the coating of the solid-metallic glass is a high-resistance coating. Preferably, the high-resistance coating has a value of greater than 0.5 micro ohmmeter [μΩηη]. Due to the high-resistance coating can be used in a dynamic application, for example at high frequencies or high rotational speeds

Eddy currents are suppressed, whereby the mechanical stability of the soft magnetic composite is maintained. Further, the soft magnetic composite described herein has improved plastic deformability which the solid metallic glass alone does not have.

According to a further preferred development, the plurality of crystalline pure iron base particles is a water-atomized or gas-atomized iron powder. By Verdüsungsart, that is water atomized or gas atomized, a texture, in particular a surface texture, of the iron powder or iron particles can be influenced. Depending on the field of use, alternative particle shapes of the iron powder are thus available which particularly preferably form the soft-magnetic composite material with the solid-metallic glass described here.

According to a further preferred development, an average

Particle size of the crystalline pure iron base particle between 30 and 500 microns, preferably between 50 and 300 microns. Particle size is understood in the present context to mean the particle diameter. In particular, a particularly homogeneous mixing of the solid-metallic glass with the plurality of crystalline pure iron-based particles can be achieved with the average particle sizes described here.

The soft magnetic composite material described here can in particular be produced by two alternative methods.

The first alternative method has the following steps:

Melting a solid-metallic glass, cooling the solid-metallic glass to a temperature, wherein the temperature is above a glass transition temperature and below a crystallization temperature. In In a next step, mixing the solid-metallic glass with a plurality of crystalline pure iron-based particles, wherein a layer of the solid-metallic glass on the plurality of crystalline

Reisenisenbasispartikeln is formed. Finally, the mixture formed in the previous step is cooled, the mixture containing the

soft magnetic composite material includes.

According to a preferred embodiment of the above method, the mixture is poured into a predetermined shape before cooling, injected or pressed. Alternatively, the mixture may be granulated prior to cooling and then pressed or injected into a predetermined shape. Thus, in a simple manner, the soft magnetic composite material can be brought into a desired shape.

The second method alternative also has the following steps:

Melting a solid-metallic glass, quenching and grinding the solid-metallic glass into a powder. In a next step, the powder is mixed with a plurality of crystalline pure iron base particles, the resulting mixture is pressed into the predetermined shape and the mixture is heated to a temperature, wherein the temperature is above a glass transition temperature and below the crystallization temperature. As the mixture is heated, the layer of solid-metallic glass forms on the plurality of crystalline ones

Pure iron base particles. In a last step of the second

Alternatively, the resulting mixture is cooled.

According to a preferred embodiment of the method is the

Glass transition temperature between 200 ° C and 600 ° C, preferably between 400 ° C and 600 ° C. At these temperatures, the method described here can be carried out particularly economically.

The features disclosed for the soft magnetic composite are also disclosed for the methods described herein and vice versa. Brief description of the drawings

Further features and advantages of the present invention will be explained below with reference to an embodiment with reference to Figures 1 to 3.

Show it:

Fig. 1 is a schematic representation for explaining a

soft magnetic composite according to a

Embodiment of the present invention;

FIG. 2 shows a schematic representation of a method for producing a soft-magnetic composite material according to FIG. 1; FIG.

Fig. 3 is a schematic alternative representation of a method for

Producing a soft magnetic composite material according to FIG. 1.

Embodiments of the invention

In the figures, like reference numerals designate the same or functionally identical elements.

Fig. 1 shows a schematic representation for explaining a

soft magnetic composite material according to an embodiment of the present invention.

Reference VI indicates a soft magnetic composite VI. The soft magnetic composite VI has a plurality of crystalline pure iron-based particles El and a solid-metallic glass G1. The plurality of crystalline pure iron base particles El has a coating of the solid-metallic glass Gl, wherein the plurality of crystalline

Reisenisenbasispartikel El over the coating of the solid-metallic glass G is in contact with each other. As is apparent from Fig. 1, the solid-metallic glass Gl is formed on an outer surface Al of the crystalline pure iron-based particles El. This means that, via the solid-metallic glass G 1, mutually adjacent crystalline pure iron-base particles can be joined via the solid-metallic glass G 1, in particular indirectly. In other words, a gap ZI between the crystalline pure iron base particles El is filled by the solid-metallic glass G, wherein a solid-metallic

Glass matrix forms and the solid-metallic glass G the plurality of crystalline pure iron base particles El together. The plurality of crystalline pure iron base particles El can be present in the form of a water atomized or gas atomized iron powder.

The coating of the solid-metallic glass G 1 shown in FIG. 1 may in particular be a high-resistance coating. A particle size of the crystalline iron-iron-based particles El may be between 30 and 500 micrometers, preferably between 50 and 300 micrometers.

FIG. 2 shows a schematic representation of a method for producing a soft-magnetic composite material according to FIG. 1.

In Fig. 2, the letters A, B, C and D refer to the

Process steps of claim 6. The shown in FIG

Method steps A to D can be carried out in particular according to the sequence shown in FIG. 2. This has the advantage that the solid-metallic glass El can in particular evenly or homogeneously distribute in the intermediate spaces ZI of the soft magnetic composite material.

The mixture prepared in step D can in particular be cast, initiated or pressed into a predetermined shape. Alternatively, the mixture may be pelletized prior to step D and then the pellets may be pressed or initiated into a predetermined shape.

FIG. 3 shows a schematic alternative representation of a method for producing a soft-magnetic composite material according to FIG. 1. In FIG. 3, the steps A1, B1, C1, D1, E1 and F1 relate to the method steps of claim 9. Those shown in FIG

Method steps AI to Fl can be carried out in particular according to the sequence shown in FIG. 3. In contrast to the process order shown in FIG. 2, it is possible to mix the mixture of solid-metallic glass Gl and the plurality of crystalline iron-iron-based particles El before heating, so that during heating, the solid-metallic glass G1 in the gaps ZI of Variety of crystalline pure iron base particles El can distribute evenly.

Thus, a soft magnetic composite material and corresponding method for producing a soft magnetic can be inexpensively

Create composite material.

Although the present invention is based on a preferred

Embodiment has been described, it is not limited thereto.

In particular, the materials and structures mentioned are only exemplary and not limited to the illustrated embodiments.

Claims

claims

A soft magnetic composite (VI) comprising: a plurality of crystalline pure iron-based particles (El); and a solid-metallic glass (G1), wherein the plurality of crystalline pure iron-base particles (E1) constitute a

Coating of the solid-metallic glass (Gl) and the plurality of crystalline pure iron base particles (El) on the coating of the solid-metallic glass (Gl) is in contact with each other.

A soft magnetic composite (VI) according to claim 1, wherein the soft magnetic composite (VI) has between 60% and 99% crystalline pure iron base particles (El) and a proportion of the solid metallic glass (G1) corresponding to between 1% and 40%, wherein the solid metal glass (G1) is based on an iron or zirconium alloy powder with phosphorus, boron, cobalt and / or niobium, the alloy powder having between 70% and 95% iron or zirconium and the proportion of phosphorus, boron, cobalt and / or Accordingly, niobium is between 5% and 30% of the alloy powder.

3. Soft magnetic composite (VI) according to one of the preceding

Claims, wherein

the coating of the solid-metallic glass (Gl) is a high-resistance coating.

4. Soft magnetic composite (VI) according to one of the preceding

Claims, wherein

the plurality of crystalline pure iron base particles (El) is a water-atomized or gas-atomized iron powder.

5. Soft magnetic composite (VI) according to any one of the preceding claims, wherein an average particle size of the crystalline

Pure iron base particle (El) is between 30 and 500 microns, preferably between 50 and 300 microns.

6. A method of producing a soft magnetic composite (VI) comprising the steps of:

A) Melting of a massive-metallic glass (G1)

B) cooling the solid-metallic glass (G1) to a temperature where the temperature is above a glass transition temperature and below a crystal ionization temperature;

C) mixing the solid-metallic glass (Gl) with a plurality of crystalline pure iron-based particles (El), wherein a layer of the solid-metallic glass (Gl) on the plurality of crystalline

Reisenisenbasispartikeln (El) is formed;

D) cooling the mixture formed in step C).

A method according to claim 6, wherein the mixture is poured, injected or pressed into a predetermined shape prior to step D).

8. The method of claim 6, wherein the mixture is processed into granules before step D) and then the granules are pressed or injected into a predetermined shape.

9. A method of producing a soft magnetic composite (VI) comprising the steps of:

AI) Melting of a solid-metallic glass (G1)

Bl) quenching and grinding the solid-metallic glass (G1) into a powder; Cl) mixing the powder with a variety of crystalline

Pure iron base particles (El);

D1) pressing the mixture formed in step Cl) into a predetermined shape and;

El) heating the mixture to a temperature wherein the temperature is above a glass transition temperature and below the crystallization temperature to form a layer of the bulk metallic glass (G1) on the plurality of crystalline iron base particles (E1);

Fl) cooling the mixture formed in step El).

10. The method according to any one of claims 6 or 9, wherein the glass transition temperature between 200 ° C and 600 ° C, preferably between 400 ° C and 600 ° C, is.

11. The method according to any one of claims 6 or 9, wherein

melting the solid-metallic glass (G1) by melting an iron or zirconium alloy powder with phosphorus, boron, cobalt and / or niobium, wherein a proportion of the iron or zirconium is between 70% and 95% and a proportion of phosphorus, boron, cobalt and / or niobium is between 5% and 30%, respectively.

A method according to any one of claims 6 or 9, wherein the plurality of crystalline pure iron base particles (El) are provided as a water-atomized or gas-atomized iron powder.