CN107396630B

CN107396630B - Method for producing soft magnetic bodies

Info

Publication number: CN107396630B
Application number: CN201680020737.7A
Authority: CN
Inventors: B.兹拉特科夫; M.门策尔; H.哈施蒂克; H.韦尔-布鲁恩; E.H.蒂姆
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2015-04-09
Filing date: 2016-04-06
Publication date: 2020-09-11
Anticipated expiration: 2036-04-06
Also published as: WO2016162383A1; DE102015105431A1; CN107396630A; EP3280558B1; EP3280558A1

Abstract

Method (100) for producing a soft magnetic object (10), comprising the steps of: a) providing a soft magnetic powder (20) with powder particles (21) consisting of a soft magnetic material (22), b) coating the powder particles (21) with an insulating coating material (31), wherein the sintering temperature of the coating material (31) is lower than the sintering temperature of the soft magnetic material (22), c) heat-treating the coating material (31) such that sintering and/or melting of the powder particles (21) is avoided during the heat treatment.

Description

Method for producing soft magnetic bodies

The invention relates to a method for producing soft magnetic bodies. Furthermore, the invention relates to a soft magnetic object and a soft magnetic body having a soft magnetic object.

Soft magnetic objects and soft magnetic bodies made of soft magnetic raw materials for the manufacture and use of soft magnetic cores for electric motors, electric valves in injection systems, actuators and sensors etc. are known from the prior art. Such soft magnetic objects may be formed, for example, as a toroid core, a ferrite core (Massekerne) or a powder core.

An inductive component whose soft magnetic core is composed of a powder composite material is known, for example, from DE 10128004 a 1. The powder composite is prepared by mixing ferromagnetic amorphous or nanocrystalline alloy powder with ferromagnetic dielectric powder and a thermoplastic or thermoset polymer.

Disadvantageously, the production of known soft-magnetic bodies or soft-magnetic bodies made of soft-magnetic bodies is often very complicated and associated with high costs. The robustness of soft magnetic objects is also generally reduced, whereby the temperature and/or corrosion resistance may be insufficient. When operating soft magnetic bodies or electrical steel sheets (elektrobeche) in an alternating magnetic field, especially at higher frequencies, soft magnetic bodies generally have a high power loss due to the generation of eddy currents. High temperatures are generated which negatively affect operation and reliability. Furthermore, during the manufacturing process, in particular by powder metallurgical routes (upon sintering), undesirable or uncontrolled crystal growth of the particles of soft magnetic material typically occurs.

It is therefore an object of the present invention to at least partly obviate the aforementioned drawbacks. In particular, it is an object of the invention to reduce the cost and complexity of manufacturing soft magnetic objects and/or soft magnetic bodies (soft magnetic components). Furthermore, it is intended to improve the temperature and/or corrosion resistance and robustness and/or to reduce the power loss or eddy current losses. In particular, it is a further object to reduce the energy losses generated in the soft-magnetic body.

The above object is achieved by a method having the features of claim 1, by a soft-magnetic object having the features of claim 8 and by a soft-magnetic body having the features of claim 10. Further features and details of the invention can be gathered from the respective dependent claims, the description and the drawings. The features and details described in connection with the method according to the invention are of course also applicable in connection with the soft-magnetic object according to the invention and the soft-magnetic body according to the invention and vice versa, so that in connection with the disclosure of the aspects of the invention always mutual reference is made.

In the following, soft magnetic objects are especially understood to mean objects made of soft magnetic raw material and/or soft magnetic material. In this case, the body can preferably have a specific design and can therefore be formed, for example, as a ring belt core, a ferrite core, a powder core and/or as a molded body or a solid part (Massivteil). Soft-magnetic bodies are in particular likewise understood to mean soft-magnetic bodies which have a low coercive field strength and are therefore unsuitable for use as permanent magnets or permanent magnets. In particular, soft-magnetic bodies or soft-magnetic objects have soft-magnetic materials that can be easily magnetized (magnetically polarized) into ferromagnetic materials, for example in a magnetic field, and thus contribute to the "enhancement" of the magnetic field. However, this magnetization does not go on permanently, as compared to permanent magnets and hard magnetic stock, and therefore no significant magnetization remains present after the magnetic field is removed. The coercive field strength is therefore significantly lower in the case of soft magnetic materials than in the case of hard magnetic materials.

The object is achieved in particular by a method for producing a soft magnetic object, in particular a soft magnetic body, comprising the steps of:

a) providing a soft magnetic powder having powder particles composed of a soft magnetic material,

b) the powder particles are coated with an insulating (i.e. non-conductive), in particular thermally stable, coating material. In particular, it is provided here that the sintering temperature of the coating material is lower than the sintering temperature of the soft magnetic material

c) Such a heat treatment, in particular sintering, of the coating material, in particular for vitrification of the coating material, is avoided, i.e. sintering and/or melting of the powder particles and/or soft magnetic material is partially or (substantially) completely prevented, during the heat treatment.

The steps are preferably carried out one after the other, with step c) in particular being carried out after step b) in terms of time. The temperature increase produced by the heat treatment is in particular related to the coated powder, i.e. the temperature increase achieved for the coating material and the powder particles. In this case, by the heat treatment, both the coating material and the soft magnetic material attain the highest process temperature for the heat treatment. In other words, the heat treatment of the powder particles coated in step b) is carried out according to step c), wherein preferably only the coating material is sintered or vitrified according to step c). The term sintering temperature especially refers to a temperature suitable for sintering and/or vitrification (i.e. conversion to the glass phase) of the respective material, i.e. the soft magnetic material or the coating material. The sintering temperature is, for example, in a range of not more than the transition temperature (particularly, glass transition temperature) or the melting temperature of each material. It is also conceivable that the sintering temperature is substantially proportional to the melting temperature and/or the transition temperature and/or the solidus temperature (solidstestumperatur) of the respective material. In particular, the transition temperature of the coating material is also lower than the melting temperature or sintering temperature of the soft magnetic material to prevent sintering or melting of the powder particles. The coating material is preferably thermally stable up to 600 ℃ (celsius) and/or up to 800 ℃ and/or up to 1200 ℃ and/or up to 1400 ℃. According to step b), the coating material is preferably selected such that its adjacent powder particles cannot be tightly bound together by heat treatment in both step b) and step c). Thus undesired crystal growth of the powder particles, i.e. the magnetic particles, and contact closure of a plurality of particles (Kontaktschluss) are avoided. Furthermore, by the method according to the invention, in particular a powder metallurgical method, the corrosion resistance of the soft magnetic object is increased due to the coating. Passivation of the particle surface is also achieved by the coating according to step b). Contamination by carbon, oxygen, phosphorus, for example, depending on the type of soft magnetic raw material, is thereby avoided. Insulating the powder particles by the coating material may also create an insulating (i.e., non-conductive) barrier. In this case, the coating material serves in particular as an insulator or binder, which is formed, for example, from starting materials and/or is used for producing a matrix material. In this sense, the starting material is preferably a precursor for the coating material (precursor) and/or the coating material is a precursor for the matrix material. The process temperature for the heat treatment or sintering is preferably selected such that the coating material is transferred into the matrix (diamagnetic or paramagnetic material) in which the powder particles are embedded. Preferably, however, the heat treatment or sintering of the coating material or the entire process according to the invention is carried out without sintering the soft magnetic material. Thus, eddy current losses can be significantly reduced and the temperature rise or heating of the soft-magnetic body during operation can be reduced with higher frequency magnetic exchange fields. Additional energy losses, such as hysteresis or residual losses, can also be reduced due to the insulating action of the coating. Thus, the insulated sintered powder particles have a high temperature stability relative to soft magnetic components that are mixed together with a polymer as a binder.

Preferably, a post-treatment, in particular a further heat treatment and/or shaping of the heat-treated powder, can be carried out after step c). The heat treatment of the coating material according to step c) here corresponds in particular to a heat treatment of the entire powder or powder particles in order to sinter the coating material, but to avoid and/or prevent melting and/or sintering of the powder particles and/or the soft magnetic material. This enables the production of soft magnets which are suitable for a very wide range of applications.

It is furthermore conceivable that in step a), in order to provide the soft magnetic powder, the soft magnetic powder is prepared beforehand. In this case, the powder has, in particular, crystalline soft-magnetic raw materials (e.g. soft iron, carbon steel, alloys based on FeAl, FeAlSi, FeNi, FeCo, etc.) and/or amorphous soft-magnetic raw materials (e.g. FeNiBSi, FeBSi, etc.) and/or soft-magnetic ferrite raw materials (e.g. MnZn ferrite, MgZn ferrite, etc.), spinel raw materials (e.g. MnMgZn, NiZn, etc.) and/or garnet raw materials (BiCa, YGd, etc.) and/or the like. Thereby resulting in an improvement of the performance of the soft-magnetic body.

Furthermore, it is possible within the scope of the present invention to form the coated powder particles into a compact, in particular by pressing, in particular after step b) and/or before step c). This achieves the advantage that the desired shape, material properties and bulk density (Pckungsdichte) of the soft-magnetic body can be reliably adjusted or improved. The term "compact" herein generally refers to the resulting shaped body or green body and is therefore not limited to pressing. The shaping can also be carried out, for example, by casting and/or pressing and/or pouring (schutten) and/or molding (Matrizenpressen) and/or hot pressing and/or cold isostatic pressing and/or hot isostatic pressing and/or ultrasonic pressing, etc. The coated powder particles are produced from uncoated powder particles, which are coated according to step b), and thus have powder particles encapsulated by the coating material. Furthermore, the sintering temperature is pressure-dependent, so that the shaping optionally can be carried out together with the sintering and/or heat treatment according to step c). Thereby, an advantage can be obtained that the temperature required for sintering can be reduced. However, it has to be taken into account that the process temperature for sintering or for heat treatment according to step c) is adjusted accordingly so that a lower sintering temperature of the soft magnetic material is not reached during the heat treatment. The compact is heated according to step c) to a temperature, for example, at most below the melting point of the soft magnetic material, but at least to a temperature at which the coating material sinters and/or transforms into the glassy phase, i.e. vitrifies. The process temperature for the heat treatment according to step c) is therefore in particular in the transition range of the coating material, in particular glass (when it is used as coating material). The heat treatment according to step c) may be carried out in vacuum or in a neutral or reducing atmosphere. It is also conceivable that the heat treatment, in particular sintering, can be carried out under air and/or nitrogen and/or argon and/or hydrogen, since the surface of the powder particles is passivated. The process temperature and/or sintering temperature of the coating material is preferably at least 50K (kelvin) and/or 100K and/or 150K and/or 200K and/or 220K below the sintering temperature of the soft magnetic material.

Furthermore, it is possible within the scope of the invention to adjust the process temperature for the heat treatment, in particular for sintering, and/or the process pressure for the heat treatment according to step c) in such a way that sintering and/or melting of the powder particles is avoided, wherein the process temperature is in particular below the sintering temperature suitable for sintering the soft magnetic material. The heat treatment, i.e., in particular sintering and/or vitrification, is preferably carried out in such a way that the process temperature and the process pressure used jointly influence the sintering temperature. Here, the compact or the coating material is preferably heated up to a process temperature, wherein the maximum process pressure is selected in the process such that sintering and/or melting of the powder particles and/or the soft magnetic material is always avoided and/or prevented. In other words, the heat treatment is preferably carried out in such a way that phase transition of the powder particles is avoided at all times. Thereby preventing a significant change of the powder particles (crystal growth or contact closure), thereby improving the performance of the soft-magnetic body.

Advantageously, in the present invention it can be provided, in particular, that the coating material is at least partially transferred into a matrix (i.e. matrix material) of diamagnetic and/or paramagnetic, in particular insulating material by means of a heat treatment in step c) and/or an additional heat treatment of the coating material before and/or after step c), such that the powder particles are embedded in the matrix. A coating of a coating material or matrix material is thus formed, which for example completely covers the powder particles (i.e. in particular the main number of powder particles of the powder). The corrosion resistance of the soft magnetic material is improved by the coating. This also has the advantage that the coating leads to a passivation of the particle surface of the powder particles. Thereby preventing contamination by, for example, carbon, oxygen, phosphorus, which causes deterioration of soft magnetic characteristics. In particular, the coating is applied by means of the coating material in such a way that an electrically non-conductive barrier is formed, which insulates the powder particles. This significantly reduces eddy currents and reduces undesirable heating of soft-magnetic objects in the magnetic alternating field at higher frequencies.

Advantageously, in the present invention it can be provided that according to step b), the coating is carried out by a dry deposition method, in particular by a chemical and/or physical gas deposition method. For example, the coating may be performed by Chemical Vapor Deposition (CVD) or Physical Vapor Deposition (PVD). In this case, for example, the starting materials for producing the coating material are used as starting materials, in particular for the deposition process. Physical gas deposition (i.e. PVD) is understood here to mean a vacuum-based coating process in which the starting materials are transferred into the gas phase and deposited, for example in a condensed manner, on the substrate to be coated (i.e. powder particles). Furthermore, evaporation methods (e.g. thermal evaporation, laser beam evaporation, arc evaporation, electron beam evaporation) and sputtering (i.e. sputter deposition or cathode sputtering) can also be used in coating, wherein the starting material is sputtered by ion bombardment during sputtering. The starting materials are transferred into the gas phase by various techniques by chemical gas deposition methods (i.e. CVD), wherein here too optionally electron beams or ion beams are used for the deposition. In the case of CVD, the coating material is deposited in particular as a solid component on the substrate surface (due to chemical reactions of the components present in the gas phase). Thus, the starting materials are present in the gas phase in volatile form and are deposited as less volatile compounds, for example as simple substances (elementar) or as oxides. The advantage of the dry process is that no expensive solvents are required, nor measures to remove or repurify the solvent are required. Furthermore, energy-intensive drying processes are dispensed with, so that the described coating method has a high flexibility with regard to the coating materials that can be used. In addition, wet techniques such as sol-gel methods may also be used for coating.

It is also conceivable to apply a single-layer coating and/or a double-layer coating. The coating can preferably have at least one or an additional oxide layer, in particular produced by oxidation of the powder and subsequent coating by glass and/or ceramic. This results in a particularly advantageous arrangement (ausgetaltung) and insulation of the soft-magnetic powder particles. Thus, the energy losses occurring in the soft-magnetic body can be reduced due to the electrically insulating effect of the coating in combination with the single particles, so that no short-circuiting of the individual particles occurs.

Advantageously, it can be provided in the invention that the coating material is obtained in particular from starting materials and that after application the coating material is present in particular in an oxidic and/or fine-grained structure, wherein the coating material is vitrified, preferably by heat treatment and/or sintering. Vitrification means here in particular that the liquid becomes solid during its cooling as a result of an increase in viscosity. In this case, no crystallization occurred and an amorphous material was formed. For the production of the coating, the starting material is considered here in particular as a starting material. For example, the coating is produced from the starting materialAnd a substrate material (matrix) is made from the coating material. These materials, in particular the matrix material, may preferably have and/or consist of glass, glass-ceramic and/or ceramic. The materials used for the coating, i.e. the coating material and/or the starting material and/or the matrix material, may furthermore have and/or consist of diamagnetic or paramagnetic materials, in particular glass materials and/or glass ceramics and/or oxides and/or mixtures of the mentioned materials. Particularly preferably, the matrix material can be glass and/or glass-ceramic and/or a combination of the mentioned materials. Furthermore, the material for the coating has in particular SiO₂And/or other metal oxides, especially Al₂O₃, Na₂O, K₂O,MgO, CaO, B₂O₃, TiO₂PbO and/or of the like, and particularly preferably quartz and/or lead-free glass and/or soda-lime glass and/or float glass and/or borosilicate glass. These materials may optionally have a mixture of different oxides with variable SiO₂And (4) proportion. Furthermore, the oxides in the glass may not be in the form of individual low molecular weight molecules, but rather exist as an extended network. Thus, for example, silicon oxide as silicate with SiO bonded to one another₄Ceramic materials may furthermore have non-oxidic materials and/or carbides and/or nitrides, such as silicon carbide SiC, boron carbide BC or boron nitride BN., the chemical composition of which differs from that of glass or glass-ceramics (Ü scheiddungen). in this case, it is essential to select the matrix material so that it has a lower transition temperature and/or melting temperature than soft-magnetic materials, so that no sintering or melting of the soft-magnetic materials takes place during step c)Optionally, the transition temperature and/or melting temperature of the matrix material is chosen to be at least 100K, preferably at least 200K, lower than the melting temperature of the soft magnetic material. Depending on the coating method, for example salts and/or volatile compounds such as hydrides are used for producing glass, glass ceramics and/or ceramics. Preferably, here, at least one of the following elements and the like is used as the precursor compound: si, Al, Na, K, Mg, Ca, B, P, Pb, Ti, Li, Be. After decomposition, corresponding elemental (elemental) components may be formed from these compounds, which react to form the corresponding oxides, either still in the gas phase or after deposition on the particle surfaces of the powder particles. These are present, for example, in oxidized form or in fine-grained structure (i.e. as "white carbon") after step b) (i.e. after coating). In particular after step c) (i.e. after sintering or heat treatment), a glass material, a ceramic material or a glass-ceramic material is then produced from the oxide.

In a further possibility, it can be provided that after step c) a thermal post-treatment, in particular by hot isostatic pressing, is carried out. Furthermore, the hot isostatic pressing may alternatively or additionally also be carried out simultaneously with step c). Here, the compact is placed, for example, in a compaction space of a device, or optionally even, for example, in a deformable container, which is, for example, heated to a heat treatment temperature, which may be below or above the sintering temperature. The compact is subjected to a pressure of at most 50MPa and/or 100MPa and/or 200MPa and/or 300 MPa. The structure of the soft-magnetic body can thereby also be compacted further (Gef ü ge). Further, for example, magnetic field treatment and/or heat treatment may be performed.

Soft magnetic objects, which are also the subject of the present invention, have:

-powder particles, in particular cores, made of soft magnetic material,

-a coating (in particular a core) made of a heat-treated insulating coating material, wherein the coating encases the powder particles.

In particular, it is provided here that the sintering temperature of the coating material is less than the sintering temperature of the soft magnetic material. The soft-magnetic body is produced in particular by the method according to the invention in such a way that the production is always carried out without a magnetic field (i.e. without the use of an external magnetic field). Here, the diameter of the core preferably substantially corresponds to the diameter of the powder particles in step a) (i.e. before the heat treatment), preferably in the range of 0.5 to 250 μm (depending on the material of the object and the purpose of use). The soft magnetic object according to the invention therefore has the same advantages as detailed for the method according to the invention. Furthermore, the soft magnetic object may preferably be manufactured by the method according to the invention.

In a further possibility, it can be provided that the layer thickness of the coating is in the range from 1nm to 10 μm, preferably in the range from 2nm to 50 nm. This results in a particularly advantageous electrical insulation and/or passivation of the powder particles, i.e. cores coated with a coating. Advantageously, the diameter of the powder particles before sintering according to step c) substantially corresponds to the diameter of the powder particles after sintering according to step c) and/or the diameter of the soft magnetic object according to the invention or the powder particles of the soft magnetic body according to the invention. This diameter remains in particular substantially constant, optionally with a certain distribution (or tolerance), throughout the process according to the invention. In this case, the layer thicknesses and diameters are preferably adjusted to one another to ensure sufficient electrical insulation and passivation of the powder particles, wherein the layer thicknesses must be sufficiently small to limit the magnetic field density of the soft-magnetic body from being too large.

Soft-magnetic bodies are also the subject of the present invention. It may be provided here that the soft-magnetic body has a soft-magnetic object according to the invention and/or is produced by a method according to the invention. In this case, the soft-magnetic body may optionally be manufactured by further post-processing steps and/or by attractive manufacturing processes such as separation (Trennen) and grinding. The soft-magnetic body according to the invention therefore has the same advantages as described in detail for the method according to the invention and/or the soft-magnetic object according to the invention.

Other advantages, features and details of the present invention will become apparent from the following description of embodiments thereof, which is described in detail with reference to the accompanying drawings. The features mentioned in the claims and in the description can be essential for the invention either individually or in any combination (erfindwingsweentlich). In the figure:

fig. 1 shows a schematic view of an uncoated spherical soft magnetic powder, with an illustration of the particle diameter,

figure 2 shows a schematic view of an uncoated irregularly shaped soft magnetic powder,

fig. 3 shows a schematic representation of a coated soft magnetic powder, with an illustration of the layer thickness,

figure 4 shows a schematic view of a coated irregular shaped soft magnetic powder,

FIG. 5 shows a schematic of a compact of regular spherical and coated powder

Figure 6 shows a schematic view of a compact made from an irregularly coated powder,

figure 7 shows a schematic view of a heat treated coated powder,

FIG. 8 shows a schematic representation of a heat treated irregular coated powder

Figure 9 shows a schematic diagram of the method steps for visualizing the method according to the invention,

figure 10 shows a schematic view of a soft-magnetic object according to the invention and an embodiment of the soft-magnetic body according to the invention.

As shown in fig. 1 and 2, the soft magnetic powder 20 may have a large number of powder particles 21 formed, for example, as spheres and/or spheroids of revolution and/or irregularities having an arbitrary shape (fig. 2). The powder particles 21 each have a diameter P of substantially 1 μm to 250 μm. It is particularly conceivable for the diameter Pmax of the individual powder particles 21 to vary within the stated range and/or within the range of maximally 0.1 μm to 50 μm. Here, the powder particles 21 have a soft magnetic material 22, which may have, for example, a crystalline soft magnetic raw material such as soft iron or carbon steel. The powder particles 21 shown in fig. 1 and 2 correspond here to uncoated powder particles 21, so that they are here uncoated powder 20 a.

In contrast, fig. 3 and 4 show the coated powder 20b with the coating material 31. The coating material 31 coats the powder particles 21 (or the core) as a coating 30, wherein the coating 30 has a layer thickness D of at least 1nm and/or a maximum of 10nm and/or a maximum of 1 μm and/or a maximum of 10 μm with a tolerance of a maximum of 1nm and/or 10 nm. It is evident here that, due to the coating 30, the powder particles 21 are (electrically) insulated from one another, whereby the eddy current losses can be significantly reduced.

Fig. 5 and 6 schematically show a compact 40 with coated powder 20b, respectively. The pressed product is formed, for example, by shaping, in particular pressing, to obtain the desired shape. The forming or pressing may also be carried out simultaneously with the heat treatment of the compact. The vitrification of the coating material 31 is caused in particular by a heat treatment, in particular by sintering of the coated powder 20b and/or the coating 30.

In fig. 7 and 8 a soft magnetic object 10 according to the invention (quasi-sintered segment) produced by a method 100 according to the invention is shown. The coating material 31 is for example transferred into the matrix material 32 or into the matrix 32 by heat treatment or sintering according to step c). According to the present invention, substantially no grain growth occurs here because the process temperature during the heat treatment is lower than the sintering temperature of the soft magnetic material 22. In this case, the powder particles 21 are isolated from each other by the amorphous phase, whereby contact closure between the powder particles is absolutely impossible.

The method steps of the method 100 according to the invention are schematically illustrated in fig. 9. According to method step 100.1, a soft magnetic powder 20 is provided. The soft magnetic powder 20 has powder particles 21 composed of a soft magnetic material 22. Soft magnetic powder 20 is produced from a crystalline soft magnetic starting material according to method step 100.6. Subsequently, the powder particles 21 are coated with a coating material 31 according to method step 100.2. To this end, according to method step 100.7, the coating material 31 and/or the starting material is produced and/or provided. Optionally, the coated powder 20b can then be pressed into a pressed article 40 in method step 100.3. Then, in method step 100.4, the coated powder 20b or the compact 40 is heat treated or sintered, wherein the process temperature for the heat treatment is lower than the sintering temperature of the soft magnetic material 22. The heat treatment is in particular carried out so as to avoid crystal growth of the powder particles 21. Here, the coating 30 ensures that adjacent powder particles 21 cannot grow together. Then, optionally, a post-treatment, such as hot isostatic pressing, is carried out according to method step 100.5.

In fig. 10 a soft-magnetic object 10 and/or a soft-magnetic body 11 is shown which may be used for example in an electric motor. The desired shape can be achieved, for example, by shaping and/or post-treatment, which can be carried out, for example, during or after sintering. The soft-magnetic object 10 according to the invention and/or the soft-magnetic body 11 according to the invention may have any shape depending on the application and is therefore not limited to the shown shape.

The foregoing description of the embodiments describes the invention only within the scope of the examples. Of course, the individual features of the embodiments can be freely combined with one another as far as technically expedient without departing from the scope of the invention.

Reference numerals

10 Soft magnetic object

11 soft magnetic body

20 Soft magnetic powder

20a uncoated powder

20b coated powder

21 powder particles

22 soft magnetic material

30 coating layer

31 coating material

32 matrix

40 pressed article

100 method

100.1 first method step

100.2 second method step

100.3 third method step

100.4 fourth method step

100.5 fifth method step

100.6 sixth method step

100.7 seventh method step

Thickness of D layer

Diameter of P particle

Claims

1. Method for manufacturing a soft magnetic object (10), comprising the steps of:

a) providing a soft magnetic powder (20) having powder particles (21) composed of a soft magnetic material (22),

b) coating the powder particles (21) with an insulating coating material (31), wherein the sintering temperature of the coating material (31) is lower than the sintering temperature of the soft magnetic material (22), wherein the coating material (31) is made of a starting material, and after coating the coating material (31) is present in an oxidic and/or fine-grained structure, wherein the starting material is a precursor for the coating material,

c) heat treating the coating material (31) to avoid sintering and/or melting of the powder particles (21) during the heat treatment, wherein the maximum process pressure for the heat treatment is adjusted according to step c) such that sintering and/or melting of the powder particles (21) is avoided, wherein the coating material (31) is vitrified by sintering, wherein the hot post-treatment is carried out after step c) by hot isostatic pressing, and wherein the hot isostatic pressing may also be carried out simultaneously with step c).

2. The method (100) according to claim 1,

it is characterized in that the preparation method is characterized in that,

forming the coated powder particles (21) into a compact (40) after step b).

3. The method (100) according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

the process temperature for the heat treatment is adjusted according to step c) in such a way as to avoid sintering and/or melting of the powder particles (21), wherein the process temperature is lower than a sintering temperature suitable for sintering the soft magnetic material (22).

4. The method (100) according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

by means of the heat treatment in step c) and/or a further heat treatment of the coating material (31) before and/or after step c), the coating material (31) is at least partially transferred into a matrix (32) of diamagnetic or paramagnetic material, so that the powder particles (21) are embedded in the matrix (32).

5. The method (100) according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

according to step b), coating is carried out by a dry deposition method.

6. The method (100) according to claim 2,

it is characterized in that the preparation method is characterized in that,

forming the coated powder particles (21) into a compact (40) by pressing after step b).

7. The method (100) according to claim 3,

it is characterized in that the preparation method is characterized in that,

the process temperature for sintering is adjusted according to step c) in such a way as to avoid sintering and/or melting of the powder particles (21), wherein the process temperature is lower than a sintering temperature suitable for sintering the soft magnetic material (22).

8. The method (100) according to claim 4,

it is characterized in that the preparation method is characterized in that,

by means of the heat treatment in step c) and/or a further heat treatment of the coating material (31) before and/or after step c), the coating material (31) is at least partially transferred into a matrix (32) of diamagnetic or paramagnetic insulating material, so that the powder particles (21) are embedded in the matrix (32).

9. The method (100) according to claim 5,

it is characterized in that the preparation method is characterized in that,

according to step b), the coating is carried out by chemical and/or physical gas deposition methods.

10. Soft-magnetic body (11) having a soft-magnetic object (10) manufactured by a method (100) according to any one of claims 1 to 9.