KR102039786B1 - Manufacture of Internal Insulated high-resistance metallic soft magnetic green compacts using hydrates - Google Patents

Abstract

A method for producing a metal molded body is provided. The method of manufacturing a metal molded body includes the steps of preparing an alloy powder containing a ferromagnetic metal element and an additional metal element, preparing a hydroxide, mixing the alloy powder, and the hydroxide to prepare a source powder, And inserting the source powder into a mold to pressurize to prepare a preform, and heat treating the preform above a decomposition temperature of the hydroxide in an inert gas and reducing gas atmosphere to prepare a molded body.

Description

Manufacture of Internal Insulated high-resistance metallic soft magnetic green compacts using hydrates}

The present invention relates to a metal powder, a method for producing the same, and a method for producing a molded article using the same, and more particularly, to a metal powder having high resistivity and insulation, a method for producing the same, and a method for producing a molded article using the same.

Along with the generalization of various electronic devices and communication devices, the development of portable electronic communication devices such as smart phones is rapidly progressing, and researches on wireless power transmission and reception technologies used in high frequency bands are being actively conducted.

Electronic devices used in high frequency bands can cause serious electromagnetic interference in general, and thus, electromagnetic wave absorbers are widely used as a countermeasure for solving the electromagnetic interference problem.

In particular, in the wireless power transmission and reception technology such as a smart phone, the use of an electromagnetic wave absorber is essential to suppress the interference of the electromagnetic field to the main circuit portion.

Conventionally, it was common to use general materials such as ferrite and carbon as the electromagnetic wave absorber. However, the conventional electromagnetic wave absorber is not only expensive in terms of material (lack of commerciality) but also difficult to control the thickness of the molded body (processability is difficult). Lack) There is a problem.

Therefore, in recent years, as a material of an electromagnetic wave absorber capable of overcoming the above problems, metal powders having an insulating film and metal molded bodies have been spotlighted as next-generation materials having excellent commerciality and workability.

For example, in Japanese application JP 5920018 (application number: JP2012116566A), a diffusion layer in which Ni and Fe are diffused to each other is formed on the surface of iron-based powder particles containing Ni or Fe, and Ni, on the surface of the diffusion layer. And a method for producing a metal powder in which an oxide layer containing Fe is formed.

However, when the metal oxide layer is formed of an insulating film, the thickness of the insulating film formed on the surface of the powder is not constant due to the frictional force between the metal powder, and the resistivity of the insulating film is only a few micro ohms.

Accordingly, in the manufacture of the metal powder and the metal molded body having the insulating film, there is a need to form a uniform insulating film and to develop a technology for increasing the resistivity of the insulating film.

One technical problem to be solved by the present invention is to provide a metal powder with an insulating film, a method of manufacturing the same, and a metal molded body including the same.

Another technical problem to be solved by the present invention is to provide a metal powder with improved uniformity of the insulating film thickness, a method of manufacturing the same, and a metal molded body including the same.

Another technical problem to be solved by the present invention is to provide a metal powder with improved resistivity characteristics, a method for producing the same, and a metal molded body including the same.

Another technical problem to be solved by the present invention is to provide a metal powder with improved formability, a method for producing the same, and a metal molded body including the same.

Another technical problem to be solved by the present invention is to provide a metal powder, a method for producing the same, and a metal molded body including the same, which has improved efficiency in a process procedure.

Technical problem for solving the present invention is not limited to those described above.

In order to solve the above technical problem, the present invention provides a method for producing a metal molded body.

According to one embodiment, the method of manufacturing a metal molded body, preparing an alloy powder containing a ferromagnetic metal element, and an additional metal element, preparing a hydroxide, by mixing the alloy powder, and the hydroxide, the source Preparing a powder; and preparing a preform by pressing the source powder into a mold and pressing the source powder, and heat-treating the preform above the decomposition temperature of the hydroxide in an inert gas and reducing gas atmosphere to prepare a molded product. can do.

According to an embodiment, the added metal element may have a higher oxidation degree to water vapor than the ferromagnetic metal element.

According to one embodiment, the ratio of the hydroxide mixed in the alloy powder may be 0.01wt% or more and 1wt% or less.

According to one embodiment, the hydroxide may be provided in a gel state.

According to an embodiment, the preparing of the hydroxide in a gel state may include mixing an oxide of a metal element dissolved in the hydroxide with a solvent.

According to one embodiment, as the ratio of the hydroxide mixed with the alloy powder is increased, the thickness of the insulating film formed on the surface of the alloy powder in the metal molded body may be thickened.

According to one embodiment, the step of preparing the molded body by heat-treating the preform, it may include that performed without additional moisture supply.

According to an embodiment, the insulating film formed on the surface of the alloy powder is an oxide of the additional metal element, an oxide of a metal element to be dissolved in the hydroxide, or a metal element to be dissolved in the additive metal element and the hydroxide. It may be an oxide including.

According to one embodiment, the alloy powder includes Fe-Si particles, by the heat treatment, the SiO ₂ insulating film may be formed on the surface of the Fe-Si particles in the metal molded body.

In order to solve the above technical problem, the present invention provides a method for producing a metal powder.

According to one embodiment, preparing an alloy powder comprising a ferromagnetic metal element, and an additional metal element, preparing a hydroxide, mixing the alloy powder, and the hydroxide to prepare a source powder, and inert And heat-treating the source powder above a decomposition temperature of the hydroxide in a gas and reducing gas atmosphere to prepare an insulated metal powder.

According to an embodiment, the insulated metal powder may be put into a mold and pressurized to manufacture a molded body.

According to an embodiment of the present invention, an alloy powder containing a ferromagnetic metal element, an additive metal element, and a hydroxide, and a hydroxide, a source powder is prepared, and the preform may be prepared by putting the source powder in a mold and pressurized. . The preform may be heat-treated at or above the decomposition temperature of the hydroxide to produce a molded article having improved uniformity and specific resistance of the insulating film formed on the surface of the alloy powder.

1 is a flowchart illustrating a method for manufacturing a molded article according to the first embodiment of the present invention.
2 is a view for explaining a metal powder, a method for manufacturing the same, and a method for manufacturing a molded body using the same according to the first embodiment of the present invention.
3 is a flowchart illustrating a method of manufacturing a metal powder according to a second embodiment of the present invention.
4 is a view for explaining a metal powder, and a manufacturing method according to a second embodiment of the present invention.
5 is a graph measuring specific resistance values according to Examples 1 to 5 and Comparative Example 1 of the present invention.
Figure 6 is a graph showing the permeability change of the metal molded body produced according to the proportion of Mg (OH) ₂ powder mixed in Fe-Si powder, according to Examples 1 to 5, and Comparative Example 1 of the present invention.
7 is a change in the FMR (Ferri-Magnetic Resonance) frequency of the metal molded body produced according to the ratio of the Mg (OH) ₂ powder mixed in the Fe-Si powder according to Examples 1 to 5, and Comparative Example 1 of the present invention Is a graph.
Figure 8a is a SEM and Mapping photograph of the alloy powder in the metal molded body according to Comparative Example 1 of the present invention.
Figure 8b is a SEM and Mapping photograph of the alloy powder in the metal molded body according to Example 3 of the present invention.
Figure 8c is a SEM and Mapping photograph of the alloy powder in the metal molded body according to Example 5 of the present invention.
9A is a TEM photograph of an alloy powder in a metal formed body according to Example 3 of the present invention.
9B is a TEM photograph of an alloy powder in a metal formed body according to Example 5 of the present invention.
10 is a TEM photograph of an insulating film formed on the surface of an alloy powder, according to Example 5 of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical idea of the present invention is not limited to the exemplary embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed contents are thorough and complete, and that the spirit of the present invention can be sufficiently delivered to those skilled in the art.

In the present specification, when a component is mentioned to be on another component, it means that it may be formed directly on the other component or a third component may be interposed therebetween. In addition, in the drawings, the thicknesses of films and regions are exaggerated for effective explanation of technical contents.

In addition, in various embodiments of the present specification, terms such as first, second, and third are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another. Thus, what is referred to as a first component in one embodiment may be referred to as a second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. In addition, the term 'and / or' is used herein to include at least one of the components listed before and after.

In the specification, the singular encompasses the plural unless the context clearly indicates otherwise. In addition, the terms "comprises" or "having" are intended to indicate that there is a feature, number, step, component, or combination thereof described in the specification, and one or more other features, numbers, steps, It should not be understood to exclude the possibility of the presence or the addition of elements or combinations thereof.

In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In addition, in this specification, a metal particle and a metal powder are interpreted to mean the particle | grains containing metal, such as a metal oxide, a metal nitride, a metal oxynitride, or a metal carbide, and the powder containing a metal, respectively. In addition, in the present specification, the metal particles and the metal powders are understood to mean particles and powders each including a plurality of metals as well as one metal.

1 is a flowchart illustrating a method of manufacturing a molded article according to a first embodiment of the present invention, and FIG. 2 is a metal powder, a method of manufacturing the same, and a method of manufacturing a molded article using the same according to a first embodiment of the present invention. It is a figure for demonstrating.

1 and 2, an alloy powder 110 including a ferromagnetic metal element and an additive metal element is prepared (S110).

According to an embodiment, the ferromagnetic metal element may include Fe or Ni.

According to another embodiment, the alloy powder 110 may be Fe or an alloy powder containing Fe. For example, the alloy powder 110 may include at least one of FeSi, FeSiAl, FeSiCr, FeSiBCr, FeCo, or FeNi.

According to an embodiment, the additive metal element may be at least one metal element having a higher oxidation degree by water vapor than the ferromagnetic metal element.

For example, the additive metal element may be Si.

In another example, the additive metal element may include S, B, C, P, Al, Ge, Ga, Cr, Ti, or Be.

According to an embodiment, when the ferromagnetic metal element is Fe and the additive metal element is Si, the alloy powder 110 may be a Fe—Si powder.

The hydroxide 120 to be mixed with the alloy powder 110 may be prepared (S120).

According to an embodiment of the present disclosure, the hydroxide 120 may include at least one of an alkali hydroxide, an alkaline earth metal hydroxide, and a rare earth hydroxide.

For example, the hydroxide 120 may include at least one of LiOH, Mg (OH) ₂ , Ba (OH) ₂ , Ca (OH) ₂ , Sr (OH) ₂ , or La (OH) ₃ . have.

According to an embodiment, the hydroxide 120 may be provided in a powder state.

According to another embodiment, the hydroxide 120 may be provided in a gel state.

For example, an oxide of a metal element dissolved in the hydroxide 120 may be provided in a gel state by mixing with a solvent. Specifically, MgO may be mixed with H ₂ -O to prepare a hydroxide in a gel state.

The source powder 130 may be manufactured by mixing the alloy powder 110 and the hydroxide 120 (S130).

According to an embodiment, the source powder 130 may be evenly mixed using a voltex mixer.

According to an embodiment, the ratio of the hydroxide 120 mixed in the alloy powder 110 may be 0.01 wt% or more and 1 wt% or less. Specifically, as will be described later, when the ratio of the hydroxide 120 mixed in the alloy powder 110 is 0.01 wt% or more and 1 wt% or less, the ratio of the hydroxide 120 in the source powder 130 is As it increases, the thickness of the insulating film 160 formed on the surface of the alloy powder in the molded body 150 may be thickened.

As described above, in the manufacturing of the source powder 130, when the hydroxide 120 is provided in a powder state, in the manufacturing process of the source powder 130, a separate washing process may be unnecessary.

On the other hand, as described above, in the manufacture of the source powder 130, when the hydroxide 120 is provided in a gel state, the reaction surface area between the alloy powder 110 and the hydroxide 120 is widened, the adhesive force This can be improved.

The preform 140 may be manufactured by putting the source powder 130 in a mold and pressing (S140).

According to an embodiment, the preform 140 may be shaped into a plate shape or a toroidal shape according to the application of the product.

According to one embodiment, the pressurization may be 1000 MPa.

In the inert gas and reducing gas atmosphere, the preform 140 may be heat-treated at a decomposition temperature of the hydroxide 120 or more, thereby forming the molded body 150 (S150).

For example, the inert gas may include Ar, or N ₂ , and the reducing gas may include H ₂ .

According to another embodiment, the inert gas and the reducing gas may be provided by mixing. For example, N ₂ and H ₂ may be provided in a mixed state.

According to one embodiment, the heat treatment above the decomposition temperature of the hydroxide 120, may be carried out at a temperature of more than 500 ℃ 1200 ℃.

In addition, the heat treatment of the preform 140 may be performed at a time of 1 minute to 10 minutes.

According to one embodiment, the molded body 150 may be manufactured without additional moisture supply. Specifically, water generated when the hydroxide 120 is hydrolyzed above the decomposition temperature of the hydroxide 120 and the additive metal element having a higher oxidation degree by water vapor than the ferromagnetic metal element undergo an oxidation reaction. To get up. An insulating layer 160 may be formed on the surface of the alloy powder 110.

In other words, as the ferromagnetic metal element is not oxidized, but as the additive metal element is oxidized, the insulating film 160 formed on the surface of the alloy powder 110 may be an oxide of the additive metal element, or the hydroxide ( It may be an oxide of a metal element solid solution in 120, or an oxide containing the additive metal element and a metal element solid solution in the hydroxide 120.

For example, when the additive metal is Si, the insulating film 160 formed on the surface of the alloy powder 110 may include SiO ₂ , for example, when the additive metal is Al, alloy powder The insulating layer 160 formed on the surface of the 110 may include Al ₂ O ₃ .

After the preform 140 is manufactured, when the heat treatment is performed at a decomposition temperature of the hydroxide 120 or more, the insulating film 160 is formed on the surface of the alloy powder 110 in the form 150. Can be.

In addition, when the heat treatment is performed above the decomposition temperature of the hydroxide 120, the hydroxide 120, which does not participate in the oxidation reaction, may remain in the molded body 150.

Unlike the first embodiment of the present invention described above, according to the second embodiment of the present invention, before the preform 140 is manufactured, heat treatment may be performed. 3 and 4, a metal powder and a method of manufacturing the same according to a second embodiment of the present invention will be described.

3 is a flowchart illustrating a method of manufacturing a metal powder according to a second embodiment of the present invention, Figure 4 is a view for explaining a metal powder, and a manufacturing method according to a second embodiment of the present invention.

3 and 4, as described above in the first embodiment of the present invention (S110 ~ S130), the alloy powder 210 (S210) and hydroxide 220 is prepared (S220), and mixed them Source powder 230 may be prepared (S230).

As described above, according to the first embodiment of the present invention, in the inert gas and reducing gas atmosphere, the source powder 230 is heat-treated above the decomposition temperature of the hydroxide 220, the insulated metal powder 240 This may be manufactured (S240).

In addition, as described above, the heat treatment at or above the decomposition temperature of the hydroxide 220 may be performed at a temperature of 300 ° C. or more and 1200 ° C. or less for 1 minute or more and 24 hours or less.

According to an embodiment, the metal powder 240 may be manufactured without additional moisture supply.

In other words, the ferromagnetic metal element is not oxidized, but as the additive metal element is oxidized, the insulating film 250 formed on the surface of the alloy powder 210 is an oxide of the additive metal element, or the hydroxide ( It may be an oxide of a metal element that is dissolved in the 220, or an oxide containing the added metal element and the metal element that is dissolved in the hydroxide 220.

According to an embodiment of the present disclosure, the metal powder 240 is a metal particle having the insulating film 250 formed thereon, and may be delivered in a powder state without being molded.

According to another embodiment, by inserting the metal powder 240 into a mold and pressurized, a molded body may be manufactured.

Hereinafter, specific experimental examples of the composite material and a method of manufacturing the same according to the embodiment of the present invention will be described.

Metal according to Example 1 Molded  Produce

As an alloy powder, a spherical Fe-Si powder having an average particle size of 35 µm prepared by a gas spraying method was prepared, and as a hydroxide, Mg (OH ₂ ) powder was prepared.

A source powder was prepared by mixing Mg (OH ₂ ) powder in a ratio of 0.2 wt% with respect to 10 g of Fe-Si powder using a voltex mixer.

The mixed source powder was put into a press and pressurized to 1000 MPa or more to prepare a preform.

The prepared preform was heat-treated at 900 ° C. for 6 hours in an H ₂ -N ₂ atmosphere of 10 vol%, and then cooled to prepare a metal molded body according to Example 1.

Metal according to Example 2 Molded  Produce

A metal molded body was manufactured in the same manner as in Example 1, except that 10 g of Fe-Si powder was mixed with Mg (OH) ₂ powder at a rate of 0.4 wt% to prepare a metal molded body.

Metal according to Example 3 Molded  Produce

A metal molded body was manufactured in the same manner as in Example 1, except that Mg (OH) ₂ powder was mixed at a ratio of 0.6 wt% to 10 g of Fe-Si powder to prepare a metal molded body.

Metal according to Example 4 Molded  Produce

A metal molded body was manufactured in the same manner as in Example 1, except that Mg (OH) ₂ powder was mixed at a rate of 0.8 wt% with respect to 10 g of Fe-Si powder to prepare a metal molded body.

Metal according to Example 5 Molded  Produce

A metal molded body was manufactured in the same manner as in Example 1, except that Mg (OH) ₂ powder was mixed at a ratio of 1.0 wt% with respect to 10 g of Fe-Si powder to prepare a metal molded body.

Metal according to Comparative Example 1 Molded  Produce

No source powder was prepared in Example 1 described above. In other words, an Fe-Si powder according to Comparative Example 1 was prepared, in which hydroxide was not mixed with the alloy powder. Thereafter, a metal molded body according to Comparative Example 1 was prepared in the same manner as in Example 1.

Metal molded bodies according to Examples 1 to 5 and Comparative Example 1 may be arranged as shown in Table 1 below.

division Proportion of Mg (OH) ₂ powder mixed in Fe-Si powder Example 1 0.2 wt% Example 2 0.4 wt% Example 3 0.6 wt% Example 4 0.8 wt% Example 5 1.0 wt% Comparative Example 1 0 wt%

5 is a graph measuring specific resistance values according to Examples 1 to 5 and Comparative Example 1 of the present invention.

Referring to FIG. 5, Mg (OH) ₂ mixed with Fe-Si powders according to Examples 1 to 5 according to Examples 1 to 5, compared to Fe-Si powders without mixing Mg (OH) ₂ powder according to Comparative Example 1 As the proportion of the powder increases from 0.2 wt% to 1.0 wt%, it can be seen that the specific resistance value of the manufactured metal molded body increases.

In particular, the specific resistance value was markedly increased when the ratio of Mg (OH) ₂ powder mixed with Fe-Si powder increased from 0.8 wt% to 1.0 wt%, and the specific resistivity value was increased. As the proportion of Mg (OH) ₂ powder increased above 1.0 wt%, it was beyond the measurement limits of the 4-point probe and measurement was not possible.

In other words, in conclusion, by controlling the ratio of the Mg (OH) ₂ powder mixed in the Fe-Si powder, it means that the specific resistance characteristics of the insulating film formed on the metal molded body can be selectively obtained.

6 is a graph showing the permeability change of the metal molded body prepared according to the ratio of the Mg (OH) ₂ powder mixed in the Fe-Si powder according to Examples 1 to 5, and Comparative Example 1 of the present invention, Figure 7 Is a FMR (Ferri-Magnetic Resonance) frequency change of the metal molded body prepared according to the proportion of the Mg (OH) ₂ powder mixed in the Fe-Si powder according to Examples 1 to 5, and Comparative Example 1 of the present invention It is a graph.

6 to 7, according to Examples 1 to 5 and Comparative Example 1, as the ratio of the Mg (OH) ₂ powder mixed in the Fe-Si powder increased from 0.2 wt% to 1.0 wt% It can be seen that the permeability of the manufactured metal molded product rises in the 1 MHz band and the moving band of the FMR frequency increases.

Particularly, when the ratio of Mg (OH) ₂ powder mixed in the Fe-Si powder is 1.0wt%, the permeability and the moving band of the FMR frequency are greatly increased, so that the FMR can be extended to the band of 40 MHz or more, but is mixed As the proportion of Mg (OH) ₂ powder increases above 1.0 wt%, it can be seen that the permeability, and the shift band of the FMR frequency, decrease.

This phenomenon, as shown in <Formula 1>, at a high temperature of 332 ℃ or more, as the proportion of the Mg (OH) ₂ powder mixed in the Fe-Si powder increases, Mg (OH) ₂ to MgO and H ₂ O H ₂ O generated in the process of decomposition may increase the amount of SiO ₂ generated by bonding with Si element.

[Formula 1]

Mg (OH) ₂ → MgO + H ₂ O (@ 332 ° C)

1) 2H ₂ O + Si → SiO ₂ + 2H ₂

SiO ₂ + MgO → Mg ₂ SiO ₄

2) 3H ₂ O + 2Al → Al ₂ O ₃ + 3H ₂

Al ₂ O ₃ + MgO → MgAl ₂ O ₄

In other words, in conclusion, due to the chemical bonding of the Fe—Si powder and the Mg (OH) ₂ powder, the thickness of the SiO ₂ insulating film formed on the surface of the alloy powder in the metal molded body may be thickened, and thus, the magnetization of the metal molded body may be increased. The value may decrease.

In addition, since the Fe-Si powder and the Mg (OH) ₂ powder are formed by chemical bonding, SiO ₂ and MgO remaining on the metal molded body may cause a pinning phenomenon, thereby reducing the magnetization value of the metal molded body. .

Figure 8a is a SEM and Mapping photograph of the alloy powder in the metal molding according to Comparative Example 1 of the present invention, Figure 8b is a SEM and Mapping photograph of the alloy powder in the metal molding according to Example 3 of the present invention, Figure 8c SEM and Mapping photographs of the alloy powder in the metal formed body according to Example 5 of the present invention.

Referring to FIG. 8A, Mg (OH) ₂ mixed in the Fe—Si powder according to Comparative Example 1 When the proportion of the powder is 0 wt%, referring to FIG. 8 b, when the proportion of the Mg (OH) ₂ powder mixed in the Fe—Si powder according to Example 3 is 0.6 wt%, and referring to FIG. 8 c. , When the ratio of the Mg (OH) ₂ powder mixed in the Fe-Si powder according to Example 5 is 1.0 wt%, SEM and Mapping photographs were taken, respectively, and the size and distribution of the alloy powder in the metal molded body were measured. . The sizes of the alloy powders in the metal compacts according to Comparative Example 1, Example 3, and Example 5 are summarized as shown in Table 2.

division Size of Alloy Powder in Metal Forms Example 3 About 10 to 30 μm Example 5 About 15 to 45 ㎛ Comparative Example 1 N / A

In the case of the metal molded body according to Comparative Example 1, no alloy powder in the molded body was observed, but in the case of the metal molded bodies according to Examples 3 and 5, the size of the alloy powder in the molded body was about 10 to 30 μm, and At about 15 to 45 μm, as the ratio of the Mg (OH) ₂ powder mixed in the Fe—Si powder increases from 0.6 wt% to 1.0 wt%, it can be seen that the size of the alloy powder in the molded article increases.

9A is a TEM picture of the alloy powder in the metal molded body according to Example 3 of the present invention, and FIG. 9B is a TEM picture of the alloy powder in the metal molded body according to the fifth embodiment of the present invention.

Referring to FIG. 9A, when the ratio of Mg (OH) ₂ powder mixed in the Fe-Si powder is 0.6 wt%, which is different from Example 3, and referring to FIG. 9B, Fe-Si, according to Example 5 When the ratio of Mg (OH) ₂ powder mixed with the powder was 1.0 wt%, the TEM photographs were measured, respectively. The thickness of the SiO ₂ insulating film formed on the surface of the alloy powder in the metal molded body according to Example 3 and Example 5 is summarized as shown in Table 3.

division Thickness of SiO ₂ Insulation Layer Example 3 About 15 nm Example 5 About 50 nm

In the case of the metal molded bodies according to Examples 3 and 5, the thickness of the SiO ₂ insulating film formed on the surface of the alloy powder in the molded bodies was about 15 nm and about 50 nm, respectively, in Mg mixed with the Fe-Si powder. As the ratio of the (OH) ₂ powder increases from 0.6 wt% to 1.0 wt%, it can be seen that the thickness of the SiO ₂ insulating film formed on the surface of the alloy powder in the molded article becomes thicker.

10 is a TEM photograph of an insulating film formed on the surface of an alloy powder, according to Example 5 of the present invention.

Referring to FIG. 10, according to Example 5, when the ratio of Mg (OH) ₂ powder mixed with Fe-Si powder was 1.0 wt%, TEM images were measured. In the case of the metal molded body which concerns on Example 5, it can be confirmed that the thickness of the insulating film formed on the surface of the alloy powder in a molded object is uniform to a fixed magnitude | size.

As mentioned above, although this invention was demonstrated in detail using the preferable embodiment, the scope of the present invention is not limited to a specific embodiment, Comprising: It should be interpreted by the attached Claim. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

110: alloy powder
120: hydroxide
130: sauce powder
140: preform
150: molded body
160: insulating film
210: alloy powder
220: hydroxide
230: sauce powder
240: metal powder
250: insulating film

Claims (11)

Preparing an alloy powder comprising a ferromagnetic metal element comprising Fe and an additive metal element comprising Si;
Preparing a hydroxide comprising Mg (OH) ₂ ;
Mixing the alloy powder and the hydroxide to prepare a source powder;
Putting the source powder into a mold and pressing to prepare a preform; And
And heat-treating the preform above the decomposition temperature of the hydroxide in an inert gas and reducing gas atmosphere to prepare a molded article.
The method of producing a metal molded body comprising a ratio of the hydroxide mixed in the alloy powder is more than 0.8 wt% less than 2 wt%.
The method of claim 1,
The said additional metal element is a manufacturing method of the metal molded object containing the oxidation degree with respect to water vapor | steam than the said ferromagnetic metal element.
delete The method of claim 1,
And the hydroxide is provided in a gel state.
The method of claim 4
Preparing the hydroxide in the gel state,
A method for producing a metal formed body comprising mixing an oxide of a metal element dissolved in the hydroxide with a solvent.
The method of claim 1
And as the ratio of the hydroxide mixed with the alloy powder increases, the thickness of the insulating film formed on the surface of the alloy powder in the metal molded body becomes thicker.
The method of claim 1,
The step of manufacturing the molded body by heat-treating the preform,
A method for producing a metal formed body comprising the step of performing without additional water supply.
The method of claim 1,
The insulating film formed on the surface of the alloy powder is at least one of an oxide of the additional metal element, an oxide of a metal element that is dissolved in the hydroxide, or an oxide containing the additional metal element and a metal element that is dissolved in the hydroxide. The manufacturing method of the metal molded object containing one.
The method of claim 1,
The alloy powder includes Fe-Si particles,
And the SiO ₂ insulating film is formed on the surface of the Fe—Si particles in the metal molded body by the heat treatment.
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