Material powder and method for producing material powder

Abstract

To provide a material powder with a fine ferromagnetic material effectively dispersed and supported on its surface.SOLUTION: A material powder has a ferromagnetic material with a diameter of 100 nanometers (nm) or less supported on its surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a material powder and a method for producing a material powder. [Background technology]

[0002] Magnetic materials having magnetic particles supported on the surface of the material are known (see, for example, Patent Document 1). Patent Document 1 describes a thermally conductive material in which BN amorphous particles are attached to the surfaces of crystalline particles formed of boron nitride (BN), and further magnetic particles (Fe) of several μm in size are attached to the surfaces of the BN amorphous particles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-145088 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the thermal conductive material described in Patent Document 1, Fe particles are attached to the surface of the non-magnetic material, so that the thermal conductive material is magnetized. In the thermal conductive material described in Patent Document 1, the diameter of the Fe particles attached to the non-magnetic material is several μm. In order to make the non-magnetic material react to a magnetic field, it is preferable that the particle diameter of the ferromagnetic material is small in order to disperse the ferromagnetic material as uniformly as possible on the surface of the non-magnetic material. On the other hand, the smaller the particle diameter of the ferromagnetic material, the more easily it aggregates. In particular, since the particles of the ferromagnetic material are easily aggregated due to the magnetic moment, it is difficult to add a granular ferromagnetic material to a non-magnetic material and disperse it uniformly. In this regard, Patent Document 1 does not describe a thermal conductive member in which particles finer than magnetic particles of several μm are uniformly dispersed.

[0005] The present invention has been made to solve at least part of the above-mentioned problems, and has an object to provide a material powder having fine ferromagnetic particles well dispersed and supported on the surface. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0007] (1) According to one aspect of the present invention, there is provided a material powder, the material powder having granular ferromagnetic material with a diameter of 100 nanometers (nm) or less carried on the surface thereof. According to this configuration, magnetism is imparted to the base material, such as non-magnetic particles carrying a ferromagnetic material, so that the base material reacts to a magnetic field. In addition, the size of the ferromagnetic material is 100 nm or less, which is smaller than the wavelength of light. As a result, in a sintered body using material powder as a raw material, the base material is sintered while maintaining its translucency. Furthermore, since the ferromagnetic material is fine, it is less likely to get caught and is less likely to come off the base material particles. In addition, since the ferromagnetic material is carried on the surface of the base material as particles with a diameter of 100 nm or less, the ferromagnetic material adheres uniformly to the surface of the base material, and magnetism is imparted to all the base material particles without any defects.

[0008] (2) In the material powder of the above form, the ferromagnetic substance may be Fe (iron) oxide. According to this configuration, since the ferromagnetic material supported on the surface of the base material is Fe oxide, magnetism is easily imparted to the base material.

[0009] (3) In the material powder of the above embodiment, the matrix in which the ferromagnetic material is supported may be a non-magnetic material exhibiting any one of paramagnetism, diamagnetism, and antiferromagnetism. According to this configuration, the ferromagnetic material carried on the surface imparts magnetism to the various material powders.

[0010] (4) According to another aspect of the present invention, there is provided a method for producing a material powder, comprising: a kneading step of mixing a base material with a complex that produces a ferromagnetic metal or metal compound upon thermal decomposition; and a degreasing step of degreasing the mixture of the base material and the complex. According to this configuration, the mixture of the base material and the complex is degreased, so that the ferromagnetic material is precipitated on the surface of the base material in a well-dispersed state. Furthermore, after the metal ions are dispersed in the kneading process, the metal ions are turned into particles through thermal decomposition in the degreasing process, so that nano-order (100 nm or less) metal or metal compound particles are supported on the surface of the base material.

[0011] The present invention can be realized in various forms, for example, in the form of a material powder, a ceramic powder, a ceramic material, a sintered body, a thermally conductive material, and a system including these, a method for producing a material powder, and a system including these, etc. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a schematic cross-sectional view of a material powder according to an embodiment of the present invention. [Diagram 2] 1 is a flowchart of a method for producing a material powder. [Diagram 3] This is a secondary electron image of the material powder. [Figure 4] 4 is an Fe element mapping image of the material powder in FIG. 3. [Diagram 5] 10 is a flowchart of a method for producing a material powder according to a second embodiment. [Figure 6] This is a secondary electron image showing that the material powder has been modified into a film-like substance. [Figure 7] 7 is an elemental mapping image showing that the film-like substance modifying the material powder of FIG. 6 is composed of Fe elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] First Embodiment FIG. 1 is a schematic cross-sectional view of a material powder 1 according to an embodiment of the present invention. The material powder 1 shown in FIG. 1 includes a base material 2 that is a non-magnetic material, and ferromagnetic particles 3 that are ferromagnetic materials supported on the surface of the base material 2. The ferromagnetic particles 3 have a grain shape with a diameter of 100 nm or less. This material powder 1 reacts to a commercially available magnet (280 mT). Members sintered using the material powder 1 as a material are used as raw materials for ceramic packages, electronic components, electronic circuit boards, and semiconductor manufacturing equipment.

[0014] Fig. 2 is a flowchart of a method for producing the material powder 1. In the production flow shown in Fig. 2, first, glass powder as the base material 2, a binder, a solvent, and a complex containing Fe ions that exhibit ferromagnetism upon thermal decomposition are prepared (step S1). Next, the glass powder other than the complex, the binder, and the solvent are combined and kneaded using a three-roll mill (step S2). Note that if the aggregation of the base material 2 is minor, step S2 can be omitted.

[0015] The complex is added to the kneaded mixture and further kneaded (step S3). The process of step S3 corresponds to the kneading process. The paste, which is a uniform mixture obtained by kneading, is dried (step S4). In order to evaporate the solvent contained in the paste, it is dried at 120°C for 12 hours. Next, a degreasing process is performed to degrease the powder, which is a mixture of the glass powder and the complex after drying (step S5). The degreasing process is performed for 5 hours at 450°C, which is a temperature at which the binder and the organometallic complex decompose. By this process, ferromagnetic particles 3 with a particle size of 100 nm or less are precipitated on the surface of the glass powder, which is the base material 2, and a material powder 1 in which the ferromagnetic particles 3 are supported on the surface of the base material 2 is manufactured. At this time, the ferromagnetic particles 3 may contain iron oxide, which is a ferromagnetic material, and the material powder 1 may contain 2 vol% of ferromagnetic particles 3 in terms of Fe2O3 so as to react with a commercially available magnet (280 mT).

[0016] 3 and 4 are explanatory diagrams of the analysis results for the material powder 1. FIG. 3 shows a secondary electron image of the material powder 1 observed using a TEM (Transmission Electron Microscope). FIG. 4 shows an Fe element mapping image of the material powder 1 shown in FIG. 3 observed using TEM-EDS (Energy Dispersive X-ray Spectroscopy). As shown in FIG. 3, in the material powder 1, particles are attached to the surface of the base material 2. In addition, from the TEM-EDS image in FIG. 4, it was confirmed that the particles uniformly attached to the entire surface of the base material 2 are ferromagnetic particles 3 containing iron oxide.

[0017] As described above, the material powder 1 of this embodiment includes the base material 2 mainly composed of glass (SiO2) and the ferromagnetic particles 3 containing iron oxide supported on the surface of the base material 2. Therefore, in the material powder 1 of this embodiment, the base material 2 of glass powder supporting the ferromagnetic particles 3 is given magnetism, and the base material 2 becomes responsive to a magnetic field. In addition, since the size of the ferromagnetic particles 3 is 100 nm or less, which is smaller than the wavelength of light, the translucency of the base material 2 is maintained in a sintered body using the material powder 1 as a raw material. Furthermore, since the ferromagnetic particles 3 are fine, the ferromagnetic particles 3 are less likely to get caught on the surface of the base material 2 and are therefore less likely to come off.

[0018] Moreover, the ferromagnetic particles 3 of this embodiment have a grain shape with a diameter of 100 nm or less. That is, the ferromagnetic particles 3 are supported on the surface of the base material 2 as small particles with a diameter of 100 nm or less, so that the ferromagnetic particles 3 are uniformly attached to the surface of the base material 2, and magnetism is imparted to all the particles of the base material 2 without defects.

[0019] In this embodiment, the ferromagnetic material carried on the surface of the base material 2 contains iron oxide. In this embodiment, the presence of the ferromagnetic particles 3 carried on the surface of the base material 2 allows the base material 2 to be easily imparted with magnetism.

[0020] In this embodiment, the base material 2 is a non-magnetic glass powder. In this embodiment, the ferromagnetic particles 3 containing iron oxide supported on the surface impart magnetism to the non-magnetic glass powder.

[0021] In the manufacturing method of the material powder 1 of this embodiment, the base material 2, which is a glass powder other than the complex, the binder, and the complex that produces a metal or metal compound exhibiting ferromagnetism by thermal decomposition are kneaded together. Then, a degreasing step is performed (step S5) to degrease the powder, which is the base material 2 after drying, which is a mixture of the glass powder and the complex, to manufacture the material powder 1. In this embodiment, the mixture of the base material 2 and the complex containing Fe element is degreased, so that the ferromagnetic particles 3 containing iron oxide are well dispersed on the surface of the base material 2. Furthermore, after the dispersion of Fe ions in the kneading step, the ferromagnetic particles 3 of the nano-order (100 nm or less) are supported on the surface of the base material 2 through thermal decomposition in the degreasing step.

[0022] <Second embodiment> FIG. 5 is a flow chart of a method for producing a material powder according to the second embodiment. The material powder produced in the second embodiment includes a base material that is an alumina (Al2O3) powder, which is a ceramic material, and ferromagnetic particles 3 containing iron oxide supported on the surface of the base material. In the production flow shown in FIG. 5, first, alumina powder as a base material, a solvent, and a complex containing Fe ions are prepared (step S11). Next, a kneading process is performed in which the solvent and base material are added to the complex and stirred (step S12). The paste after stirring is dried using an evaporator (step S13). The drying using the evaporator is performed under reduced pressure to prevent decomposition of the complex, and while stirring to prevent precipitation of the material powder. A degreasing process is performed to degrease the powder that is a mixture of the alumina powder and the complex after drying (step S14). The degreasing process is performed under the same conditions as in the first embodiment, and the material powder is produced.

[0023] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0024] In the above first and second embodiments, the material powder 1 in which the ferromagnetic particles 3 as a ferromagnetic body are supported on the surface of the base material 2 has been described. However, the material powder is deformable within the range in which ferromagnetic particles having a diameter of 100 nm or less are supported on the surface of the base material 2. For example, the base material 2 may be a non-magnetic body other than glass powder or alumina powder, or a well-known non-magnetic material exhibiting any of paramagnetism, diamagnetism, and antiferromagnetism may be used.

[0025] 6 and 7 are explanatory diagrams of the analysis results for the material powder 1. FIG. 6 shows a secondary electron image of the material powder 1 observed using a SEM (Scanning Electron Microscope). FIG. 7 shows an Fe element mapping image of the material powder 1 shown in FIG. 6 observed using an SEM-EDS. The ferromagnetic material supported on the surface of the base material 2 may not be granular, and may be a film covering at least a part of the surface of the base material 2. The ferromagnetic material contained in the ferromagnetic particles 3 may be other than iron oxide, and may be, for example, Fe, Co, Ni, Cr, etc. Also, the material powder 1 may have a general magnet composition combining multiple metals such as Sm-Co and Nd-Fe. In the first embodiment, the material powder 1 contains 2 vol% of the ferromagnetic particles 3 in terms of Fe2O3, but it may contain less than 2 vol% of the ferromagnetic particles 3 or other ferromagnetic materials, or it may contain more than 2 vol% of the ferromagnetic particles 3 or other ferromagnetic materials.

[0026] The manufacturing method of the material powder 1 shown in Figs. 2 and 5 is an example, and can be modified to include a kneading step of mixing the base material 2 with a complex that produces a metal or metal compound exhibiting ferromagnetism by thermal decomposition, and a degreasing step of degreasing the mixture of the base material 2 and the complex. For example, drying of the mixture and the degreasing step may be performed in one step. The type of the complex that produces a metal or metal compound exhibiting ferromagnetism by thermal decomposition may be other than the complex (e.g., a metal compound), and fatty acid salts are preferable from the viewpoint of coating properties and solubility. However, the complex can be modified to a range that is soluble in organic solvents such as nitrates, sulfates, and ammonium salts, and water. In the process of step S2 in the manufacturing flow of the first embodiment shown in Fig. 2, the base material 2, the binder, and the solvent may be kneaded by a ball mill instead of a three-roll mill.

[0027] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0028] The present invention can also be realized in the following forms. [Application example 1] A material powder, A material powder characterized by having granular ferromagnetic material with a diameter of 100 nanometers (nm) or less supported on the surface. [Application example 2] The material powder according to Application Example 1, A material powder characterized in that the ferromagnetic material is Fe (iron). [Application example 3] The material powder according to Application Example 1 or Application Example 2, A material powder, wherein a base material in which a ferromagnetic substance is supported is a non-magnetic substance exhibiting any one of paramagnetism, diamagnetism, and antiferromagnetism. [Application example 5] A method for producing a material powder, comprising: A kneading step of mixing a base material with a complex that produces a metal or metal compound exhibiting ferromagnetism upon thermal decomposition; a degreasing step of degreasing a mixture of the base material and the complex; A manufacturing method comprising: [Explanation of symbols]

[0029] 1…Material powder 2…Base material 3...Ferromagnetic particles

Claims

1. A material powder, A material powder characterized in that granular ferromagnetic material having a diameter of 100 nanometers (nm) or less is carried on the surface.

2. 2. The material powder of claim 1 , A material powder, wherein the ferromagnetic material is Fe (iron) oxide.

3. 3. The material powder of claim 2, A material powder, wherein a base material in which a ferromagnetic substance is supported is a non-magnetic substance exhibiting any one of paramagnetism, diamagnetism, and antiferromagnetism.

4. A method for producing a material powder, comprising: A kneading step of mixing a base material with a complex that produces a metal or metal compound exhibiting ferromagnetism upon thermal decomposition; a degreasing step of degreasing a mixture of the base material and the complex; A manufacturing method comprising:

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