WO2022259547A1

WO2022259547A1 - Lubricant, combination of lubricants, powder mixture, combination of raw materials for powder mixture and production method for sintered body

Info

Publication number: WO2022259547A1
Application number: PCT/JP2021/022394
Authority: WO
Inventors: 航介浦島; 征宏有福; 洋大守; 大樹福永
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2021-06-11
Filing date: 2021-06-11
Publication date: 2022-12-15
Also published as: WO2022260009A1; JPWO2022260009A1

Abstract

A lubricant of the present invention includes a lubricant A, which has a melting point of 60–85°C, and the ratio of particles with a particle size of 63 μm or less is at least 88 mass% with respect to the total amount of lubricant when sifted using a JIS-standard sieve.

Description

Lubricant, combination of lubricants, powder mixture, combination of raw materials for powder mixture, and method for producing sintered body

The present disclosure relates to a lubricant, a combination of lubricants, a powder mixture, a combination of raw materials for the powder mixture, and a method for producing a sintered body.

Lubricants are usually used for lubrication, for example, to reduce friction between solids in contact with each other. Lubricants include liquid lubricating oil, semi-solid grease, solid lubricants, and the like. For example, in the powder metallurgy method, powdery solid lubricants (powdered lubricants) are used.

Among powder metallurgy methods, particularly in the mold molding method, a powder mixture is usually used in which a powdery lubricant is mixed with the raw material powder in order to reduce the friction between the mold wall surface and the green compact. The powder mixture is obtained by mixing iron-based powder, which is the main raw material powder, with auxiliary raw material powder such as copper powder, graphite powder, machinability improving powder, and lubricant powder.

By including a powdery lubricant in the powder mixture, the powder characteristics such as fluidity and compactibility in the powder mixture are improved, making it easier to extract the compacted compact from the mold. Lubricant powders include, for example, metallic soap-based lubricants such as stearic acid and metal salts thereof, organic lubricants (wax-based lubricants), fatty acid amide-based lubricants, and metallic soap-based lubricants and fatty acid amide-based lubricants. Mixtures with lubricants are mentioned (see, for example, Patent Documents 1 and 2).

The lubricant should be selected after taking into consideration the miscibility with the metal powder, the powder characteristics when the powder is mixed, the ease with which the green compact can be extracted after compression molding, and the dissipation of the lubricant when sintering the green compact. selected. Among them, zinc stearate is widely used as a lubricant because of its relatively excellent lubricating properties and cost. Such lubricants are generally mixed in advance with the powder mixture before use. There is also a method of applying a lubricant to the wall surface of the mold, but this requires a special device, which makes the production cost of the sintered body relatively high.

However, metal soap-based lubricants, typified by zinc stearate, have the problem of contaminating the surface of products, exhaust ducts, etc. when sintering green compacts. is desired to be replaced. As organic lubricants, in addition to the lubricants described in Patent Documents 1 and 2, amide compounds having long-chain alkyl groups have been proposed (see Patent Document 3, for example).

JP-A-4-136104 JP-A-11-193404 Japanese translation of PCT publication No. 2008-513602

When a powder mixture containing a lubricant is compression-molded using a mold, it is desirable that the molded body should be easy to extract from the mold, that is, the molded body should be easily ejected. A sintered body obtained by sintering a molded body is also likely to have a poor appearance due to irregularities formed on its surface.

The present disclosure is a powder containing a lubricant and a combination of lubricants, the lubricant, or the combination of the lubricants, which can improve the ejectability of the molded body and can produce a sintered body with suppressed appearance defects. It is an object of the present invention to provide a mixture, a combination of raw materials for the powder mixture, and a method for producing a sintered body using the powder mixture or the combination of the raw materials for the powder mixture.

Specific means for achieving the above object are as follows.
<1> Lubricant A having a melting point of 60 ° C. to 85 ° C. is included, and when sieved using a JIS standard sieve, the proportion of particles having a particle diameter of 63 μm or less is 88 mass with respect to the total amount of the lubricant. % or more.
<2> Lubricant A includes oleic acid amide, erucic acid amide, ricinoleic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N - The lubricant according to <1>, containing at least one selected from the group consisting of oleyl palmitamide, N-oleyl-hydroxystearic acid amide, stearic acid, and N-oleyl palmitamide.
<3> The proportion of particles that do not pass through a JIS standard sieve with an opening of 150 μm is 5% by mass or less with respect to the total amount of the lubricant. lubricant.
<4> Lubricant A having a melting point of 60° C. to 85° C.;
a lubricant B, which is a fatty acid bisamide;
A combination of lubricants in which the ratio of particles having a particle size of 63 μm or less is 88% by mass or more with respect to the total amount of the combination of lubricants when sieved using a JIS standard sieve.
<5> Lubricant A includes oleic acid amide, erucic acid amide, ricinoleic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N - The lubricant combination according to <4>, which contains at least one selected from the group consisting of oleyl palmitamide, N-oleyl-hydroxystearic acid amide, stearic acid, and N-oleyl palmitamide.
<6> The combination of lubricants according to <4> or <5>, wherein the melting point of the lubricant B is 140°C or higher and lower than 150°C.
<7> Lubricant B is methylenebisstearic acid amide, methylenebislauric acid amide, methylenebishydroxystearic acid amide, ethylenebiscaprylic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebisisostearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisstearic acid amide, hexamethylenebishydroxystearic acid amide, butylenebishydroxystearic acid amide, N,N'-distearyladipamide, N,N'-distearylsebacamide, methylenebisoleamide, ethylenebisoleamide, ethylenebiserucamide, hexamethylenebisoleamide, N,N containing at least one selected from the group consisting of '-dioleyladipamide, N,N'-dioleylsebacamide, m-xylylenebisstearamide and N,N'-distearylisophthalamide A combination of lubricants according to any one of <4> to <6>.
<8> The lubricant A contains at least one selected from the group consisting of erucamide and oleamide,
The combination of lubricants according to <4>, wherein the lubricant B contains ethylenebisstearic acid amide.
<9> Any one of <4> to <8>, wherein the mass ratio of the lubricant A to the lubricant B is 1:9 to 9:1. combination of lubricants.
<10> The proportion of particles that do not pass through a JIS standard sieve with an opening of 150 μm is 5% by mass or less with respect to the total amount of the combination of lubricants <4> to <9> A combination of lubricants according to any one of the preceding claims.
<11> A powder mixture containing a raw powder and a combination of the lubricant according to any one of <1> to <3> or the lubricant according to any one of <4> to <10> .
<12> A powder mixture containing a raw powder and a combination of the lubricant according to any one of <1> to <3> or the lubricant according to any one of <4> to <10> A combination of raw materials for
<13> A method for producing a sintered body by sintering the powder mixture obtained from the powder mixture according to <11> or the combination of raw materials for the powder mixture according to <12>.

According to the present disclosure, a lubricant and a combination of lubricants, the lubricant, or the combination of the lubricants that can improve the ejectability of the molded body and can produce a sintered body with suppressed appearance defects It is possible to provide a powder mixture and a combination of raw materials for the powder mixture, and a method for producing a sintered body using the powder mixture or the combination of raw materials for the powder mixture.

Hereinafter, the lubricant, the combination of lubricants, the powder mixture, the combination of raw materials for the powder mixture, and the method for producing the sintered body of the present disclosure will be described. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and their ranges, which do not limit the present invention.
In the present disclosure, a numerical range indicated using "to" indicates a range including the numerical values before and after "to" as the minimum and maximum values, respectively.
In the numerical ranges described step by step in the present disclosure, the upper limit value or lower limit value described in one numerical range may be replaced with the upper limit value or lower limit value of another numerical range described step by step. . Moreover, in the numerical ranges described in the present disclosure, the upper or lower limits of the numerical ranges may be replaced with the values shown in the examples.
In the present disclosure, each component may contain multiple types of applicable substances. When there are multiple types of substances corresponding to each component, the content rate or content of each component means the total content rate or content of the multiple types of substances unless otherwise specified.
Particles corresponding to each component in the present disclosure may include a plurality of types. When there are multiple types of particles corresponding to each component, the particle size of each component means a value for a mixture of the multiple types of particles unless otherwise specified.

[lubricant]
The lubricant of the present disclosure contains lubricant A having a melting point of 60 ° C. to 85 ° C., and when sieved using a JIS standard sieve, the proportion of particles having a particle size of 63 μm or less is the total amount of the lubricant. 88% by mass or more of the lubricant.

By using the lubricant of the present disclosure, it is possible to improve the ejectability of the molded body and manufacture a sintered body with suppressed appearance defects. More specifically, since the lubricant of the present disclosure contains lubricant A having a relatively low melting point, it tends to make it easier to pull out the molded body from the mold, that is, to improve the pull-out performance of the molded body. Furthermore, when sieved, the proportion of particles having a particle diameter of 63 μm or less is 88% by mass or more of the total amount of the lubricant. As a result, it is possible to manufacture a sintered body obtained by sintering a molded body, in which unevenness on the surface is reduced and appearance defects are suppressed.

The lubricant of the present disclosure is preferably used for powder metallurgy, for example. The lubricants of the present disclosure may be used in applications other than powder metallurgy.

The ratio of particles having a particle diameter of 63 μm or less when sieved using a JIS standard sieve is 90% by mass or more with respect to the total amount of the lubricant, from the viewpoint of suitably suppressing the appearance defect of the sintered body. , 95% by mass or more, or 100% by mass.
In the present disclosure, the ratio of particles having a particle size of a specific particle size or less (e.g., 63 μm or less) is obtained by sieving the lubricant with a JIS standard sieve having the specific particle size (e.g., 63 μm). It is defined as the percentage of particles that pass through the sieve.

The particle size that serves as a reference for sieving is not limited to 63 μm or less, and may be 50 μm or less or 43 μm or less. For example, the proportion of particles having a particle diameter of 50 μm or less may be 90% by mass or more, 95% by mass or more, or 100% by mass with respect to the total amount of the lubricant. . The proportion of particles having a particle diameter of 43 μm or less may be 90% by mass or more, 95% by mass or more, or 100% by mass with respect to the total amount of the lubricant.

　JIS standard sieve conforms to JIS-Z-8801-1:2006 and corresponds to ISO3310-1:2000. When ISO3310-1:2000 is used, it is preferable to use a sieve having square meshes as in JIS-Z-8801-1:2006.

In the lubricant of the present disclosure, the proportion of particles that do not pass through a JIS standard sieve with an opening of 150 μm is, from the viewpoint of suitably suppressing poor appearance of the sintered body, the total amount of the lubricant. is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. The proportion of the aforementioned particles may be 0% by mass or 0.5% by mass or more relative to the total amount of the lubricant.

When the lubricant of the present disclosure is composed of Lubricant A, the proportion of particles having a particle diameter of 63 μm or less when sieved using a JIS standard sieve is 88% by mass or more with respect to the total amount of Lubricant A. I wish I had. When the lubricant of the present disclosure is composed of lubricant A and a lubricant other than lubricant A, the proportion of particles having a particle size of 63 μm or less when sieved using a JIS standard sieve is It may be 88% by mass or more with respect to the total amount of lubricants other than agent A.

(Lubricant A)
Lubricants of the present disclosure include Lubricant A having a melting point of 60°C to 85°C. The lubricant may contain one kind of lubricant A, or may contain two or more kinds of lubricants A.
In the present disclosure, melting point is a value measured by differential scanning calorimetry (DSC).

Lubricant A is oleic acid amide, erucic acid amide, ricinoleic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid It preferably contains at least one selected from the group consisting of amide, N-oleyl-hydroxystearic acid amide, stearic acid, and N-oleyl palmitamide, oleic acid amide, erucic acid amide, ricinoleic acid amide, stearin More preferably, it contains at least one selected from the group consisting of acids and N-oleyl palmitoamide. Among them, the lubricant A preferably contains at least one of erucamide and oleamide, more preferably erucamide, from the viewpoint of extractability of the molded article.

The content of lubricant A may be 50% by mass to 100% by mass, 70% by mass to 100% by mass, or 90% by mass to 100% by mass with respect to the total amount of the lubricant. There may be.

(Lubricants other than Lubricant A)
The lubricant of the present disclosure may contain lubricants other than Lubricant A. Examples of lubricants other than lubricant A include fatty acid amides having a melting point of over 85° C., metallic soap-based lubricants, and the like. When lubricants other than lubricant A are used, one of them may be used alone, or two or more of them may be used in combination.

Fatty acid amides with a melting point exceeding 85°C include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, N-lauryllauric acid amide, N-palmitylpalmitic acid amide, N-stearyl stearic acid amide, N-stearyl-hydroxystearic acid amide and the like.

Examples of metal soap-based lubricants include metal salts of fatty acids having 12 to 22 carbon atoms and at least one metal selected from the group consisting of lithium, magnesium, calcium, barium, zinc and strontium.

The fatty acid having 12 to 22 carbon atoms may be a saturated fatty acid having 12 to 22 carbon atoms or an unsaturated fatty acid having 12 to 22 carbon atoms. The number of carbon atoms in the fatty acid may be 16-20, or 16-18.

Fatty acids having 12 to 22 carbon atoms include saturated fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid and behenic acid, and unsaturated fatty acids such as linoleic acid, linolenic acid, oleic acid and erucic acid. mentioned.

Specific examples of metal soap-based lubricants include lithium stearate, calcium stearate, barium stearate, and zinc stearate.

The content of the lubricant other than the lubricant A with respect to the total amount of the lubricant may be more than 0% by mass and 50% by mass or less, may be 5% by mass to 40% by mass, 10% by mass to 20% by mass. may be At this time, the total content of lubricant A and lubricants other than lubricant A should be 100% by mass.

[Combination of lubricants]
The combination of lubricants of the present disclosure contains lubricant A having a melting point of 60° C. to 85° C. and lubricant B, which is a fatty acid bisamide, and when sieved using a JIS standard sieve, the particle size is The proportion of particles with a diameter of 63 μm or less is at least 88% by weight, based on the total amount of the lubricant combination.

By using the combination of lubricants of the present disclosure, it is possible to improve the fluidity of the powder mixture and the extractability of the molded body, and to manufacture a sintered body with suppressed appearance defects. By combining the lubricant A and the lubricant B, it is possible to improve the fluidity of the powder mixture and also improve the extractability of the compact.

In the present disclosure, the combination of lubricants may be a mixture of lubricants comprising at least Lubricant A and Lubricant B, wherein a lubricant comprising Lubricant A and a lubricant comprising Lubricant B are mixed. It may be a combination of those prepared separately. For example, if a combination of a lubricant containing lubricant A and a lubricant containing lubricant B are prepared without mixing, when producing a powder mixture, the lubricant containing lubricant A and the lubricant A lubricant containing agent B may be mixed.

In the combination of lubricants of the present disclosure, the proportion of particles having a particle diameter of 63 μm or less when sieved using a JIS standard sieve is the lubricant from the viewpoint of suitably suppressing poor appearance of the sintered body. It may be 90% by mass or more, 95% by mass or more, or 100% by mass with respect to the total amount of the combination.

The particle size that serves as a reference for sieving is not limited to 63 μm or less, and may be 50 μm or less or 43 μm or less.

In the combination of lubricants of the present disclosure, the proportion of particles that do not pass through a JIS standard sieve with an opening of 150 μm is the ratio of particles that do not pass through the sieve, from the viewpoint of suitably suppressing poor appearance of the sintered body. is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, relative to the total amount of The proportion of the aforementioned particles may be 0% by weight or 0.5% by weight or more relative to the total amount of the lubricant combination.

The configuration of the lubricant A included in the combination of lubricants of the present disclosure is the same as the configuration of the lubricant A included in the lubricant of the present disclosure described above, so description thereof will be omitted.

(Lubricant B)
The lubricant combination of the present disclosure includes Lubricant B, which is a fatty acid bisamide. The combination of lubricants may contain one lubricant B, or may contain two or more lubricants B.

The melting point of lubricant B may be 140°C or higher and lower than 150°C, or may be 140°C or higher and 148°C or lower.

Examples of the lubricant B include methylenebisstearic acid amide, methylenebislauric acid amide, methylenebishydroxystearic acid amide, ethylenebiscaprylic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, and ethylenebisstearic acid amide. , ethylenebisisostearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisstearic acid amide, hexamethylenebishydroxystearic acid amide, butylenebishydroxystearic acid amide, N ,N'-distearyladipamide, N,N'-distearylsebacamide, methylenebisoleamide, ethylenebisoleamide, ethylenebiserucamide, hexamethylenebisoleamide, N,N' -dioleyladipate, N,N'-dioleylsebacamide, m-xylylenebisstearate and N,N'-distearylisophthalamide. Among them, the lubricant B more preferably contains ethylenebisstearic acid amide from the viewpoint of fluidity of the powder mixture.

As a preferable combination of lubricant A and lubricant B, lubricant A is at least selected from the group consisting of erucic acid amide and oleic acid amide from the viewpoint of the balance between the fluidity of the powder mixture and the ejection property of the compact. Lubricant B preferably contains ethylenebisstearic acid amide.
The total content of erucamide and oleamide in lubricant A is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and 90% by mass to 100% by mass. % is more preferred.
The content of ethylenebisstearic acid amide in Lubricant B is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and 90% by mass to 100% by mass. is more preferred.

Lubricant A: Lubricant B, which is the mass ratio of Lubricant A and Lubricant B, is 1: 9 to 9: 1 from the viewpoint of the balance between the fluidity of the powder mixture and the ejection property of the compact. It is preferably 2:8 to 8:2, and even more preferably 3:7 to 7:3.

The total content of lubricant A and lubricant B with respect to the total amount of the lubricant combination is preferably 50% by mass to 100% by mass. Further, the total content of lubricant A and lubricant B may be 60% by mass to 95% by mass, or may be 80% by mass to 90% by mass.

(other lubricants)
The lubricant combinations of the present disclosure may include other lubricants than Lubricant A and Lubricant B. Other lubricants include amide-based lubricants other than lubricant A and lubricant B, and metal soap-based lubricants described above. Examples of amide-based lubricants other than Lubricant A and Lubricant B include fatty acid amides having a melting point exceeding 85°C.
Other lubricants may be used alone or in combination of two or more.

The content of other lubricants with respect to the total amount of the combination of lubricants may be more than 0% by mass and 50% by mass or less, may be 5% by mass to 40% by mass, and may be 10% by mass to 20% by mass. There may be. At this time, the total content of lubricant A, lubricant B and other lubricants should be 100% by mass.

[Powder mixture]
A powder mixture of the present disclosure includes a raw powder and a lubricant of the present disclosure described above or a combination of lubricants of the present disclosure described above. By using this powder mixture, it is possible to improve the ejectability of the molded body, and to manufacture a sintered body with suppressed appearance defects.
The powder mixtures of the present disclosure are preferably used, for example, for powder metallurgy.

Examples of raw material powders include main raw material powders containing iron as a main component, auxiliary raw material powders that improve the properties of the sintered body, and the like.
In addition, containing iron as a main component means that the content of iron in the raw material powder is 50% by mass or more of the entire raw material powder.

Examples of main raw material powders include iron-based powders such as pure iron powders and iron-based alloy powders that may contain inevitable impurities (oxygen, silicon, carbon, manganese, etc.). The main raw material powder may be used singly or in combination of two or more.

The average particle size of the main raw material powder is preferably 30 μm to 150 μm, more preferably 50 μm to 100 μm.
In the present disclosure, the average particle size is the particle size (D50) when the accumulation from the small size side is 50% in the volume-based particle size distribution measured by laser diffraction.

The iron-based powder can be produced, for example, by atomizing molten iron or molten iron alloy into fine particles, reducing the fine particles, and then pulverizing the fine particles.

The auxiliary raw material powder is not particularly limited as long as it is a raw material powder that can improve the properties of the sintered body. Examples include powders that enhance machinability.

Examples of auxiliary raw material powders include metal powders and inorganic powders other than the main raw material powders. The auxiliary raw material powders may be used singly or in combination of two or more.

Metal powders include powders of copper, nickel, chromium, molybdenum, tin, vanadium, manganese, and the like.

Examples of inorganic powder include sulfides such as manganese sulfide and manganese disulfide; nitrides such as boron nitride; oxides such as boric acid, magnesium oxide, potassium oxide and silicon oxide; graphite such as natural graphite and artificial graphite; Powders such as sulfur can be mentioned.

The average particle size of the secondary raw material powder is preferably 2 μm to 100 μm, more preferably 5 μm to 50 μm.

The content of the main raw material powder in 100 parts by mass of the raw material powder is preferably 90 to 99 parts by mass, more preferably 95 to 98 parts by mass.

The content of the auxiliary raw material powder is preferably 1 to 10 parts by mass, more preferably 2 to 5 parts by mass, out of 100 parts by mass of the raw material powder.

With respect to 100 parts by mass of the raw material powder, the content of the lubricant and the content of the combination of lubricants are each independently preferably 0.1 parts by mass to 2.0 parts by mass, and 0.2 parts by mass. It is more preferably up to 1.5 parts by mass, and even more preferably 0.3 parts by mass to 1.0 parts by mass.

(other ingredients)
The powder mixtures of the present disclosure may contain other ingredients than the raw powders, the lubricants of the present disclosure, and the combinations of lubricants of the present disclosure. Other components include binders. When the powder mixture contains a binder, it tends to be possible to suppress segregation, scattering, and the like of the raw material powder.

The binder is not particularly limited, and includes polyolefin, acrylic resin, polystyrene, styrene-butadiene rubber, ethylene glycol distearate, epoxy resin, rosin ester, and the like.

When the powder mixture of the present disclosure contains a binder, the content of the binder is preferably 0.01 parts by mass to 1.0 parts by mass with respect to 100 parts by mass of the raw material powder, and 0.1 parts by mass to 1 part by mass. 0.0 parts by mass is more preferable.

The powder mixture of the present disclosure is obtained by mixing the raw material powder, the lubricant of the present disclosure or the combination of lubricants of the present disclosure, and other components as necessary. Mixing of the raw material powder with the lubricant of the present disclosure or the combination of lubricants of the present disclosure can be performed using commonly used mixers such as vane mixers, V-shaped mixers, double cone mixers (W-cone), etc. It can be done using a machine.

A raw material combination for a powder mixture of the present disclosure includes a raw powder and a lubricant of the present disclosure or a combination of lubricants of the present disclosure. The combination of raw materials for the powder mixture of the present disclosure may be a mixture of raw powder and lubricant or a mixture of raw powder and lubricant combination. Alternatively, it may be a combination of the raw material powder and the lubricant of the present disclosure or the combination of the lubricant of the present disclosure, which are prepared without mixing, and when producing the molded body, the raw material powder and the present The disclosed lubricants or combinations of lubricants of the present disclosure may be used in admixture.
Preferred conditions for the combination of raw materials for the powder mixture of the present disclosure are the same as those for the powder mixture of the present disclosure described above, and therefore description thereof is omitted.

[Method for producing sintered body]
The method for producing a sintered body of the present disclosure is a method of producing a sintered body by sintering a powder mixture obtained from the powder mixture of the present disclosure described above or a combination of raw materials for the powder mixture of the present disclosure described above. .
The method for producing a sintered body of the present disclosure preferably includes filling a powder mixture in a mold, compression molding the powder mixture filled in the mold to form a compact, and sintering the molded body extracted from the

In the method for producing a sintered body according to the present disclosure, by using the powder mixture described above, it is possible to improve the ejectability of the molded body, and it is possible to produce a sintered body with suppressed appearance defects.

In the method for producing a sintered body of the present disclosure, the powder mixture filled in the mold may be compression molded. The molding temperature, molding pressure, and the like are not particularly limited, and may be appropriately adjusted depending on the composition of the powder mixture, the amount added, the shape inside the mold, and the like.

In the method for producing a sintered body of the present disclosure, the sintered body is produced by sintering the powder mixture, preferably by sintering the molded body extracted from the mold. Conditions for sintering the powder mixture or compact are not particularly limited, and ordinary sintering methods can be employed.

Hereinafter, the present disclosure will be described in further detail based on examples. In addition, the present invention is not limited to the following examples.

[Examples 1 to 14 and Comparative Examples 1 to 14]
Atomized iron powder for powder metallurgy with an average particle size of 75 μm was prepared as the main raw material powder, and electrolytic copper powder with an average particle size of 30 μm and graphite powder with an average particle size of 10 μm were prepared as auxiliary raw material powders. Next, with respect to 97.5 parts by mass of iron powder, 1.5 parts by mass of copper powder and 1.0 parts by mass of graphite powder, Lubricant A or a lubricant mixture of Lubricant A and Lubricant B shown in Table 1 and below was added in an amount of 0.8 parts by mass. In each example and each comparative example, the ratio of particles having a particle diameter of 63 μm or less when sieved using a JIS standard sieve is the numerical value shown in Table 1 with respect to the total amount of lubricant A and A lubricant mixture was used. Table 1 shows the ratio of lubricant A and lubricant B in each example and each comparative example. After that, a mixture of the raw material powder and the lubricant was put into a V-shaped mixer and mixed for 30 minutes to obtain a powder mixture of each example and each comparative example.
<Lubricant A>
Erucamide (melting point: 78°C to 81°C)
Oleic acid amide (melting point: 75°C)
<Lubricant B>
Ethylene bis stearamide (melting point: 145°C)

(Fluidity of powder mixture)
Fluidity evaluation of the powder mixture obtained in each example and each comparative example was performed by the fluidity test method specified in JIS Z 2502 (2012). Evaluation criteria are as follows.
-Evaluation criteria-
A Powder mixture flowed within 30 seconds.
B The powder mixture flowed within more than 30 seconds and within 35 seconds.
C The powder mixture did not flow or the powder mixture flowed for more than 35 seconds.
Table 1 shows the results. If the evaluation is A or B, the fluidity of the powder mixture is good.

(Compactibility of powder mixture)
Evaluation of the compactibility of the powder mixture obtained in each example and each comparative example was performed by supplying 7 g of the powder mixture into a mold, molding a cylindrical molded body with a diameter of 11.3 mm at a molding pressure of 700 MPa, and using the following criteria. based on
-Evaluation criteria-
A: The density of the cylindrical compact was 7.10 g/cm ³ or more.
B The density of the cylindrical compact was 7.06 g/cm ³ or more and less than 7.10 g/cm ³ .
C The density of the cylindrical compact was less than 7.06 g/cm ³ .
Table 1 shows the results. If the evaluation is A or B, the compactibility of the powder mixture is good.

(Extractability of cylindrical compact)
Ejectability of the cylindrical molded body in each example and each comparative example was measured by measuring the ejection pressure when the cylindrical molded body used for evaluating the compaction property of the powder mixture was extracted from the mold, and was based on the following criteria. evaluated.
-Evaluation criteria-
A The extraction pressure was 8 MPa or less.
B The extraction pressure was more than 8 MPa and 15 MPa or less.
The C extraction pressure was above 15 MPa.
Table 1 shows the results. If the evaluation is A or B, the ejection property of the cylindrical molded body is good.

(Appearance evaluation)
The evaluation of the appearance in each example and each comparative example was carried out by visually confirming the surface of the sintered body obtained by firing the cylindrical compact used for evaluating the compactibility of the powder mixture in nitrogen at about 1100 ° C., as follows. Evaluated based on criteria.
-Evaluation criteria-
A: Roughness due to surface unevenness was not observed on the surface of the sintered body.
Roughness due to surface unevenness was observed on the surface of the C sintered body.
Table 1 shows the results. If the evaluation is A, the appearance of the sintered body is good.

As shown in Table 1, by using the powder mixtures of Examples 1 to 14, it was possible to manufacture sintered bodies with excellent ejectability of molded bodies and suppressed appearance defects.

All publications, patent applications and technical standards mentioned herein are to the same extent as if each individual publication, patent application and technical standard were specifically and individually noted to be incorporated by reference. incorporated herein by reference.

Claims

Lubricant A having a melting point of 60° C. to 85° C. is included, and when sieved using a JIS standard sieve, the proportion of particles having a particle diameter of 63 μm or less is 88% by mass or more with respect to the total amount of the lubricant. some lubricant.
Lubricant A includes oleic acid amide, erucic acid amide, ricinoleic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitin 2. The lubricant according to claim 1, comprising at least one selected from the group consisting of acid amide, N-oleyl-hydroxystearic acid amide, stearic acid, and N-oleyl palmitamide.
The lubricant according to claim 1 or 2, wherein the proportion of particles that do not pass through a JIS standard sieve with an opening of 150 μm is 5% by mass or less relative to the total amount of the lubricant.
Lubricant A having a melting point of 60° C. to 85° C.;
a lubricant B, which is a fatty acid bisamide;
A combination of lubricants in which the ratio of particles having a particle size of 63 μm or less is 88% by mass or more with respect to the total amount of the combination of lubricants when sieved using a JIS standard sieve.
Lubricant A includes oleic acid amide, erucic acid amide, ricinoleic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitin 5. The lubricant combination of claim 4, comprising at least one selected from the group consisting of acid amide, N-oleyl-hydroxystearic acid amide, stearic acid, and N-oleyl palmitamide.
The combination of lubricants according to claim 4 or 5, wherein the melting point of the lubricant B is 140°C or higher and lower than 150°C.
Lubricant B includes methylenebisstearic acid amide, methylenebislauric acid amide, methylenebishydroxystearic acid amide, ethylenebiscaprylic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylene. Bisisostearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisstearic acid amide, hexamethylenebishydroxystearic acid amide, butylenebishydroxystearic acid amide, N, N '-distearyladipamide, N,N'-distearylsebacamide, methylenebisoleamide, ethylenebisoleamide, ethylenebiserucamide, hexamethylenebisoleamide, N,N'-dio (4) containing at least one selected from the group consisting of railadipamide, N,N'-dioleylsebacamide, m-xylylenebisstearic acid amide and N,N'-distearyl isophthalic acid amide; A lubricant combination according to any one of claims 1 to 6.
The lubricant A contains at least one selected from the group consisting of erucamide and oleamide,
5. The lubricant combination of claim 4, wherein said lubricant B comprises ethylene bis stearamide.
The lubricant according to any one of claims 4 to 8, wherein the mass ratio of the lubricant A to the lubricant B, namely lubricant A: lubricant B, is 1:9 to 9:1. combination.
Any one of claims 4 to 9, wherein the ratio of particles that do not pass through the sieve when sieved with a JIS standard sieve with an opening of 150 μm is 5% by mass or less with respect to the total amount of the combination of lubricants. A combination of lubricants as described above.
A powder mixture containing a raw material powder and the lubricant according to any one of claims 1 to 3 or the combination of lubricants according to any one of claims 4 to 10.
A raw material for a powder mixture containing a raw material powder and the lubricant according to any one of claims 1 to 3 or the combination of lubricants according to any one of claims 4 to 10. combination.
A method for producing a sintered body by sintering the powder mixture obtained from the powder mixture according to claim 11 or the combination of raw materials for the powder mixture according to claim 12 to produce a sintered body.