Copper-based mixed powders for powder metallurgy

Abstract

To provide a copper-based mixed powder for powder metallurgy, which contains Si and Ni and / or Co, exhibits high sinterability in an inert atmosphere, can produce a Cu-(Ni, Co)-Si based alloy sintered compact by a general sintering method, and can be adjusted to desired strength and conductivity by an aging treatment after sintering.SOLUTION: A copper-based mixed powder for powder metallurgy is obtained by mixing an alloy powder (powder A) containing 0.2 wt.% or more and 6.0 wt.% or less of Si, the balance being Cu and inevitable impurities, and an alloy powder, a mixed powder or a simple powder (powder B) containing 30.0 wt.% or more of Ni and / or Co in total, and the balance being Cu and inevitable impurities. The mixed powder has a total content of Si of 0.2 wt.% or more and 6.0 wt.% or less, and a total content of Ni and / or Co of 0.8 wt.% or more and 40.0 wt.% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a copper-based mixed powder for powder metallurgy. More specifically, the copper-based mixed powder contains Si and Ni and / or Co, but exhibits high sinterability in an inert atmosphere, allowing for the production of Cu-(Ni,Co)-Si alloy sintered bodies by general sintering methods. Furthermore, the produced Cu-(Ni,Co)-Si alloy sintered bodies can be adjusted to have high strength and high conductivity (thermal conductivity) by controlling the amount of Si, Ni and / or Co, and by aging treatment after sintering. Therefore, this invention relates to a copper-based mixed powder for powder metallurgy that can be suitably used in the production of sintered parts requiring strength, conductivity, and heat dissipation. [Background technology]

[0002] In recent years, as metal parts have become smaller, copper alloys are now required to have not only strength but also improved heat dissipation, that is, improved thermal conductivity.

[0003] Cu-(Ni,Co)-Si alloys are widely used as alloy systems that can achieve both strength and electrical conductivity (thermal conductivity) by finely precipitating (Ni,Co)-Si compounds through aging treatment after solution treatment.

[0004] However, because it contains Si, a difficult-to-sinter element, and Ni and Co have very slow diffusion rates in the Cu matrix, sintering is difficult. Therefore, producing Cu-(Ni,Co)-Si alloys by sintering is extremely difficult and has not yet been put into practical use.

[0005] One method for sintering difficult-to-sinter powders is to produce a sintered body by creating a compacted powder with a density close to true density using high molding pressure, thereby promoting sintering.

[0006] By applying high molding pressure to produce a compacted powder close to its true density, the adhesion between the powder particles is improved, making it possible to manufacture a sintered body with a high sintering density.

[0007] However, producing compacted powder close to true density requires extremely high molding pressure compared to general molding, which presents a problem.

[0008] Furthermore, the aforementioned method is a physical method that improves the adhesion between powder particles to obtain a high sintering density, and is not a method that fundamentally improves the sinterability of the powder particles themselves.

[0009] Therefore, there is a need for the development of copper-based mixed powders that can be manufactured using conventional sintering methods, by chemically improving the sinterability of the powder particles themselves through methods that enhance the reactivity between the powder particles. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 10-158766 [Patent Document 2] Japanese Patent Publication No. 2015-160960 [Patent Document 3] Japanese Patent Publication No. 2018-135557 [Overview of the project] [Problems that the invention aims to solve]

[0011] Patent Document 1 discloses a Cu-Ni-Si-Al-Fe-Mn(-B-Mo) powder sintered body.

[0012] The sintered body disclosed in Patent Document 1 does not exhibit segregation because it is made from alloy powder produced by the atomization method, but it requires 3 hours of sintering in a hydrogen-reducing atmosphere, which presents a problem of being difficult to sinter.

[0013] Furthermore, because it is a multi-component system, even after aging treatment, trace amounts of added elements remain in the Cu matrix, resulting in a problem of low electrical conductivity (thermal conductivity).

[0014] Patent document 2 discloses a powder sintered body of a Cu-Ni-Si alloy.

[0015] The sintered body disclosed in Patent Document 2 has the problem that segregation is likely to occur because the raw material is a mixed powder composed of individual powders of Cu, Ni, and Si, making it difficult to achieve a uniform structure.

[0016] Furthermore, the presence of coarse Ni2Si particles larger than 2 μm, accounting for more than 2% of the total area, presents a problem in that it is not possible to improve the strength of Cu-Ni-Si alloys.

[0017] Patent Document 3 discloses a powder sintered body obtained by adding elemental Ti powder as a sintering aid to a Cu-Ni-Si-S(-Fe-Sn) alloy.

[0018] Although the sintered body disclosed in Patent Document 3 has improved sinterability due to the addition of a sintering aid, it requires sintering for 2 hours under a vacuum atmosphere, and has the problem of being difficult to sinter.

[0019] Furthermore, there is the problem that elemental Ti powder, used as a sintering aid, is expensive.

[0020] As a result of conducting many trial productions and experiments through a chemical approach to improve the sinterability of the Cu-(Ni,Co)-Si powder itself, an alloy powder (Powder A) containing 0.2 wt% or more and 6.0 wt% or less of Si, with the balance consisting of Cu and unavoidable impurities, and an alloy powder or mixed powder or single powder (Powder B) containing 30.0 wt% or more in total of Ni and / or Co, with the balance consisting of Cu and unavoidable impurities, are mixed. As long as it is a copper-based mixed powder in which the total Si content is 0.2 wt% or more and 6.0 wt% or less, and the total Ni and / or Co content is 0.8 wt% or more and 40.0 wt% or less, it exhibits high sinterability in an inert atmosphere without adding elements other than the main elements Cu, Ni, Co, and Si as sintering aids. Therefore, a Cu-(Ni,Co)-Si-based alloy sintered body can be manufactured by a general sintering method, and the manufactured sintered body is a sintered body sufficiently equipped with high strength and high conductivity (high thermal conductivity). Moreover, through aging treatment after sintering, it can be adjusted to a sintered body with even higher strength and high conductivity (high thermal conductivity), thus achieving the above technical problem with remarkable findings.

Means for Solving the Problem

[0021] The above technical problem can be solved by the present invention as follows.

[0022] The present invention relates to a copper-based mixed powder for powder metallurgy. The copper-based mixed powder contains 0.2 wt% or more and 6.0 wt% or less of Si, and is composed of an alloy powder (Powder A) with the balance consisting of Cu and unavoidable impurities, and an alloy powder or mixed powder or single powder (Powder B) containing 30.0 wt% or more in total of Ni and / or Co, with the balance consisting of Cu and unavoidable impurities, which are mixed. The total Si content in the copper-based mixed powder is 0.2 wt% or more and 6.0 wt% or less, and the total Ni and / or Co content is 0.8 wt% or more and 40.0 wt% or less.

[0023] Furthermore, the present invention relates to the copper-based powder for powder metallurgy in which the above-mentioned powder A and / or powder B contain one or more elements selected from the group consisting of Zn, Sn, Mg, and P, and the total amount of Zn, Sn, Mg, and P contained in the copper-based powder for powder metallurgy is 3.0% by weight or less.

[0024] Furthermore, the present invention has an apparent density of 4.0 g / cm³. 3 The following describes the copper-based mixed powder for powder metallurgy, wherein 70% or more of the particle size distribution consists of particles with a diameter of 106 μm or less.

[0025] Furthermore, the present invention relates to the above-mentioned copper-based mixed powder for powder metallurgy, which contains 0.1% or more by weight of a lubricant and 1.0% or less by weight.

[0026] Furthermore, the present invention relates to a sintered body obtained by sintering a compacted molded body of the aforementioned copper-based mixed powder for powder metallurgy.

[0027] Furthermore, the present invention relates to a sintered body obtained by further aging the aforementioned sintered body.

[0028] Furthermore, the present invention relates to a method for manufacturing the aforementioned sintered body. [Effects of the Invention]

[0029] In this specification, the term "conductive" is used to include the meaning of thermal conductivity, and "Ni and / or Co" may be represented as "X". Furthermore, "total" refers to the sum of elements, including those contained in unavoidable impurities.

[0030] The present invention relates to a copper-based mixed powder manufactured by mixing an alloy powder (hereinafter referred to as "Powder A") containing 0.2% to 6.0% by weight of Si, with the remainder being Cu and unavoidable impurities, with an alloy powder, mixed powder, or elemental powder (hereinafter referred to as "Powder B") containing a total of 30.0% or more by weight of Ni and / or Co, with the remainder being Cu and unavoidable impurities. In this copper-based mixed powder, the total Si content is 0.2% to 6.0% by weight, and the total Ni and / or Co content is 0.8% to 40.0% by weight. Therefore, when heated to 800°C or higher, elemental diffusion between Powder A and Powder B begins. The Si contained in the Cu matrix of Powder A reduces the activity of Ni and / or Co contained in Powder B, significantly improving the diffusion rate of Ni and / or Co in the Cu matrix. As a result, sintering proceeds rapidly, making it a highly sinterable copper-based mixed powder.

[0031] Furthermore, as sintering progresses, Cu, X, and Si diffuse uniformly, and eventually all X and Si become solid solutions in the Cu matrix. Rapid cooling of this solution results in a homogeneous supersaturated solid solution.

[0032] Furthermore, by subjecting the resulting homogeneous supersaturated solid solution to age treatment, intermetallic compounds mainly composed of X2Si precipitate finely and age harden, resulting in a sintered body with high strength.

[0033] Furthermore, the aging process significantly reduces the amount of X and Si dissolved in the Cu matrix, resulting in a sintered body with high conductivity.

[0034] The copper-based mixed powder in this invention can have its strength, conductivity, and, if necessary, corrosion resistance adjusted by controlling the content of X and Si and by aging treatment.

[0035] Because the copper-based alloy powder in this invention has very high sinterability, it can be sintered in a general pure nitrogen atmosphere or a nitrogen-hydrogen mixed atmosphere without the need to add special sintering aids, thus enabling the production of Cu-X-Si alloys by sintering. [Modes for carrying out the invention]

[0036] The present invention is a copper-based mixed powder for powder metallurgy, comprising an alloy powder (Powder A) containing 0.2% to 6.0% by weight of Si, with the remainder being Cu and unavoidable impurities, and an alloy powder, mixed powder, or elemental powder (Powder B) containing 30.0% or more by weight of X, with the remainder being Cu and unavoidable impurities, and containing a total of 0.2% to 6.0% by weight of Si and a total of 0.8% to 40.0% by weight of Ni and / or Co.

[0037] If the Si content in the Cu matrix of powder A, which is an alloy powder, is less than 0.2% by weight, the Si content is too low. This may prevent sufficient reduction of the activity of X contained in powder B, slowing down the diffusion rate of X in the Cu matrix and potentially hindering sintering.

[0038] Furthermore, if the Si content exceeds 6.0% by weight, the Si may not be able to completely dissolve in the Cu matrix of powder A, resulting in the formation of a Cu-Si compound phase in powder A. This may reduce the sinterability of the mixed powder of powder A and powder B.

[0039] Furthermore, if the Si content exceeds 6.0% by weight, the Cu-Si powder reacts with moisture in the air to generate H2 gas, which may cause damage due to increased internal pressure in the storage container and the formation of SiO2 oxides that inhibit sintering. This is undesirable because it worsens the handling properties of the powder.

[0040] The method for producing the powder is not particularly limited, but alloy powder produced by atomization is preferred, and more preferably, alloy powder produced by water atomization.

[0041] This is because the metal powder produced by the water atomization method has an irregular shape, making it excellent for compaction and molding.

[0042] Powder B is an alloy powder, mixed powder, or elemental powder containing a total of 30.0% by weight or more of X, with the remainder being Cu and unavoidable impurities.

[0043] Powder B may be an alloy powder, mixed powder, or single-component powder in which X accounts for 100% by weight in total, and may not contain Cu.

[0044] If the total amount of X is less than 30.0% by weight, the mixing ratio of powder B to powder A becomes large, which reduces the amount of Si contained in the Cu matrix of powder A. As a result, the activity of X in the mixed powder does not decrease sufficiently, which slows down the diffusion rate of X in the Cu matrix and may prevent sintering from progressing, making it undesirable.

[0045] The method for producing the powder is not particularly limited, but in the case of an alloy composition containing Cu in the remainder, the water atomization method is preferred.

[0046] This is because the irregular shape of the metal powder makes it excellent for compaction and molding.

[0047] In the case of individual or mixed powders of Ni and Co, it is preferable to use powders that are mass-produced using industrial methods.

[0048] Because it is highly pure and inexpensive.

[0049] The copper-based mixed powder in this invention can be produced by mixing powder A and powder B such that the total Si content is 0.2% to 6.0% by weight and the total X content is 0.8% to 40.0% by weight.

[0050] If the total amount of Si contained in the copper-based mixed powder is less than 0.2% by weight, the activity of X will not decrease sufficiently, the diffusion rate of X in the Cu matrix will slow down, and sintering will not proceed, which is undesirable.

[0051] Furthermore, the upper limit of 6.0% by weight for Si content in copper-based mixed powder is because the upper limit for Si content in powder A is 6.0% by weight, and the mixed powder of powder A and powder B will not exceed the upper limit for Si content in powder A. However, it may be 5.8% by weight or less.

[0052] If the total amount of X contained in the copper-based mixed powder is less than 0.8% by weight, it is undesirable because sufficient strength and corrosion resistance may not be obtained.

[0053] Furthermore, if the Si content exceeds 40.0% by weight, the ratio of Si to X decreases, the activity of X does not decrease sufficiently, the diffusion rate of X slows down, and sintering does not proceed, which is undesirable.

[0054] If a balance between conductivity and strength is particularly important, it is preferable to mix X and Si so that the atomic ratio is 2:1 (hereinafter referred to as the "Corson alloy composition").

[0055] When mixing with a Corson alloy composition, the total amount of Si contained in the copper-based mixed powder is preferably 0.2% to 3.0% by weight, and the total amount of X is preferably 0.8% to 12.0% by weight.

[0056] This is because if the total amount of Si is less than 0.2% by weight and the total amount of X is less than 0.8% by weight, the Si and X dissolved in Cu may not precipitate through aging treatment, and high conductivity may not be obtained.

[0057] Furthermore, if the total amount of Si exceeds 3.0% by weight and the total amount of X exceeds 12.0% by weight, the solid solubility limit in Cu will be exceeded, resulting in the retention of coarse X2Si, which may significantly reduce the strength.

[0058] Furthermore, since this invention significantly improves the diffusion rate of X by introducing Si into the Cu matrix, a Corson alloy composition is not necessary if strength and corrosion resistance are more important than conductivity.

[0059] If the composition is not a Colson alloy, the atomic ratio of Si to X does not necessarily have to be 2:1; the proportion of X can be increased as long as the sinterability is satisfied.

[0060] In this invention, unavoidable impurities refer to impurities that are not intentionally added but are inevitably introduced during the manufacturing process.

[0061] The total amount of unavoidable impurities in this invention is 0.1% by weight or less.

[0062] Powder A or powder B may contain Zn, Sn, Mg, and P in the form of alloy powder or mixed powder.

[0063] By incorporating Zn, Sn, Mg, and P, sinterability and strength can be improved.

[0064] The total content of Zn, Sn, Mg, and P is preferably 3.0% by weight or less.

[0065] This is because if the total amount exceeds 3.0% by weight, the amount of solid solution in the Cu matrix will increase, which may reduce conductivity.

[0066] Furthermore, Zn and Mg have high vapor pressures, which could cause them to evaporate during sintering and contaminate the sintering furnace.

[0067] The apparent density of the copper-based mixed powder of the present invention is 4.0 g / cm³. 3 The following is preferable, where 70% or more of the particle size distribution is 106 μm or smaller.

[0068] This is because it contributes to sinterability and powder compaction properties.

[0069] The apparent density is 4.0 g / cm³. 3 If the particle size distribution exceeds this limit, or if particles smaller than 106 μm account for less than 70%, the sinterability deteriorates, making compaction difficult.

[0070] The apparent density can be determined using the measurement method specified in JIS Z 2504.

[0071] The particle size distribution can be determined by calculating the proportion of powder particles smaller than 106 μm in the total, based on the particle size distribution values ​​obtained according to the JIS Z 2510 standard.

[0072] The copper-based mixed powder used in this invention has a compacted density of 6 g / cm³. 3 ~8g / cm3 This allows for the formation of compacted powder molded articles with a bending strength of 8 MPa or more.

[0073] A lubricant can be added to the copper-based mixed powder in this invention.

[0074] Adding a lubricant improves lubricity, making it easier to mold compacted powder products.

[0075] The amount of lubricant added is preferably 0.1% to 1.0% by weight, and more preferably 0.2% to 0.8% by weight.

[0076] If the amount is less than 0.1% by weight, the improvement in lubricity will be insufficient, which may make it difficult to remove the powder from the mold during compaction molding. If it is added in amounts exceeding 1.0% by weight, the sinterability will decrease.

[0077] Furthermore, if the lubricant content exceeds 1.0% by weight, the amount of lubricant evaporated during sintering increases, which may contaminate the sintering furnace.

[0078] The lubricant used in this invention is not particularly limited, but metal soaps such as zinc stearate and EBS-based waxes can be suitably used.

[0079] The Cu-X-Si alloy produced by sintering the copper-based mixed powder of the present invention can undergo age hardening by controlling the cooling rate after sintering, thereby improving its strength and conductivity.

[0080] For even higher strength and conductivity, these can be adjusted through aging treatment. [Examples]

[0081] Examples of the present invention are shown, but the present invention is not limited to these.

[0082] The formulations of the copper-based mixed powders for each example and comparative example are shown in Tables 1 and 2, which will be described in detail below.

[0083] The copper-based mixed powders in Examples 1 and 2 were prepared by mixing powder A and powder B so that they had a Colson alloy composition (X:Si = 2:1 (atomic ratio)).

[0084] As powder A, we used Cu-1.1Si and Cu-2.1Si (wt%) powders prepared by atomization, and as powder B, we used elemental Ni powder (manufactured by Vale).

[0085] The copper-based mixed powders were mixed to obtain Cu-4.2Ni-1.1Si and Cu-7.6Ni-1.9Si (by weight) as the overall composition, and then subjected to sintering and aging treatments to obtain each sintered body.

[0086] The copper-based mixed powder in Example 3 was mixed to achieve a Colson alloy composition.

[0087] As powder A, we used Cu-0.6Si (wt%) powder prepared by atomization, and as powder B, we used elemental Ni powder.

[0088] The copper-based mixed powder was mixed to have an overall composition of Cu-2.4Ni-0.6Si (by weight), and then subjected to sintering and aging treatment to obtain a sintered body.

[0089] In Example 4, Cu-5.8Si (wt%) powder prepared by atomization was used as powder A, and elemental Ni powder was used as powder B. The mixture was combined to obtain a Cu-3.0Ni-5.6Si (wt%) mixture, and sintering was performed to obtain a sintered body.

[0090] The copper-based mixed powder in Example 5 was mixed to achieve a Colson alloy composition.

[0091] Using Cu-2.1Si (weight%) powder prepared by atomization as powder A and Cu-30.0Ni (weight%) powder prepared by atomization as powder B, they were mixed to obtain a sintered body by performing the aforementioned sintering and aging treatments.

[0092] In Example 6, Cu-0.6Si (wt%) powder prepared by atomization was used as powder A, and elemental Ni powder was used as powder B. The mixture was combined to obtain a Cu-10.0Ni-0.4Si (wt%) mixture, and sintering was performed to obtain a sintered body.

[0093] In Example 7, Cu-2.1Si (weight%) powder prepared by atomization was used as powder A, and elemental Ni powder was used as powder B. These were mixed to obtain a Cu-35.0Ni-1.3Si (weight%) mixture, and sintering was performed to obtain a sintered body.

[0094] Example 8 was mixed to achieve the Colson alloy composition.

[0095] Using Cu-0.6Si (wt%) powder prepared by atomization as powder A and elemental Co powder (manufactured by Yumicore Co., Ltd.) as powder B, the mixture was prepared to have an overall composition of Cu-2.4Co-0.6Si (wt%), and then sintered and aged to obtain a sintered body.

[0096] Example 9 was mixed to achieve the Colson alloy composition.

[0097] A mixture of Cu-1.1Si (weight%) powder prepared by atomization as powder A and a mixture of elemental Ni powder and elemental Co powder as powder B were mixed to obtain a sintered body by sintering and aging treatment.

[0098] Example 10 was mixed to achieve the Colson alloy composition.

[0099] A mixed powder consisting of Cu-1.1Si (weight%) powder prepared by atomization as powder A, and elemental Cu powder and elemental Ni powder prepared by atomization as powder B, was mixed to obtain a sintered body by sintering and aging treatment.

[0100] Example 11 was mixed to achieve the Colson alloy composition.

[0101] Using Cu-0.6Si (wt%) powder prepared by atomization as powder A and Ni elemental powder as powder B, and further adding 3.0 wt% of Sn elemental powder prepared by atomization, the mixture was prepared to obtain a Cu-2.3Ni-0.6Si-2.9Sn (wt%) overall composition, and then sintered and aged to obtain a sintered body.

[0102] Example 12 was mixed to achieve the Colson alloy composition.

[0103] Using Cu-0.6Si (wt%) powder prepared by atomization as powder A and elemental Ni powder as powder B, 3.0 wt% of Cu-8.0P (wt%) powder prepared by atomization and 1.0 wt% of elemental Zn powder (manufactured by Toho Zinc Co., Ltd.) were added, and the mixture was combined to obtain a Cu-2.3Ni-0.6Si-1.0Zn-0.2P (wt%) mixture. Sintering and aging treatment were then performed to obtain a sintered body.

[0104] Example 13 was mixed to achieve the Colson alloy composition.

[0105] Using Cu-0.6Si-0.2Mg (weight%) powder prepared by atomization as powder A and elemental Ni powder as powder B, they were mixed to achieve an overall composition of Cu-2.3Ni-0.6Si-0.2Mg (weight%), and then subjected to sintering and aging treatment to obtain a sintered body.

[0106] Example 14 was mixed to achieve the Colson alloy composition.

[0107] Coarse-grained Cu-1.1Si (wt%) powder prepared by atomization was used as powder A, and elemental Ni powder was used as powder B. These were mixed to achieve an overall composition of Cu-4.2Ni-1.1Si (wt%), and then sintered and aged to obtain a sintered body.

[0108] Comparative Example 1 was mixed to achieve the Colson alloy composition.

[0109] Using Cu-0.1Si (wt%) powder prepared by atomization as powder A and elemental Ni powder as powder B, the mixture was prepared to achieve an overall composition of Cu-0.4Ni-0.1Si (wt%), and sintering was performed to obtain a sintered body.

[0110] Comparative Example 2 used Cu-10.0Si (wt%) powder prepared by atomization as powder A and elemental Ni powder as powder B. The mixture was then combined to obtain a sintered body with an overall composition of Cu-10.0Ni-9.0Si (wt%).

[0111] Comparative Example 3 was mixed to achieve the Colson alloy composition.

[0112] Using Cu-2.1Si (wt%) powder prepared by atomization as powder A and Cu-20.0Ni (wt%) powder prepared by atomization as powder B, they were mixed to obtain a sintered body with an overall composition of Cu-6.1Ni-1.5Si (wt%).

[0113] Comparative Example 4 used Cu-2.1Si (wt%) powder prepared by atomization as powder A and elemental Ni powder as powder B. The mixture was then combined to obtain a sintered body with an overall composition of Cu-45.0Ni-1.2Si (wt%).

[0114] Comparative Example 5 was mixed to achieve the Colson alloy composition.

[0115] Using Cu-0.6Si (wt%) powder prepared by atomization as powder A and Ni elemental powder as powder B, and further adding 3.0 wt% Sn elemental powder and 2.0 wt% Zn elemental powder prepared by atomization, the mixture was prepared to obtain a sintered body by mixing the resulting mixture to have an overall composition of Cu-2.3Ni-0.6Si-2.9Sn-1.9Zn (wt%), followed by sintering and aging treatment.

[0116] Comparative Examples 6 and 7 were mixed to obtain the Colson alloy composition.

[0117] Coarse-grained Cu-1.1Si (wt%) powder, prepared by atomization, was used as powder A, and elemental Ni powder was used as powder B. These were mixed to achieve an overall composition of Cu-4.2Ni-1.1Si (wt%), and sintering was performed to obtain a sintered body.

[0118] (apparent density) The apparent density (AD) of each copper-based mixed powder was determined according to the measurement method specified in JIS Z 2504.

[0119] (particle size distribution) The particle size distribution was determined by calculating the proportion of powder particles smaller than 106 μm from the total particle size distribution values ​​obtained according to the JIS Z 2510 standard.

[0120] (Sintering method) Each copper-based mixed powder from the examples and comparative examples was filled into a ring-shaped mold, and the compacted powder density was 6.5 g / cm³. 3 A compacted powder body with an outer diameter of approximately 14 mm, an inner diameter of 7 mm, and a height of 7 mm was prepared, and sintered in a nitrogen atmosphere at a sintering temperature of 1000°C for 1 hour.

[0121] Each sintered body was obtained by water cooling when aging treatment was performed, and by air cooling when aging treatment was not performed.

[0122] (Sinterability) Sinterability is measured at a compacted powder density of 6.5 g / cm³. 3 In contrast, the sintering density is 7.2 g / cm³. 3 If the above (density change rate of 10% or more) is achieved, it can be considered good.

[0123] Among the sintered bodies that showed good sinterability, those with an atomic ratio of X to Si of 2:1 (Corson alloy composition) underwent aging treatment to measure their electrical conductivity and compression strength.

[0124] (Statute of limitations) The aging treatment involved heat treatment by holding the material in a nitrogen atmosphere for 2 hours, followed by air cooling to obtain each sintered body.

[0125] The aging temperature was set at 475°C when X was Ni and 525°C when X was Co.

[0126] (Electrical conductivity) The electrical conductivity (%IACS) of the sintered body after aging treatment was determined by converting the density to the true density (= density of the sintered body / density of copper) from the value measured with an eddy current conductivity meter SIGMA CHECK (manufactured by ETHER NDE) for a green compact having a size of approximately 30 mm × 12 mm × 5 mm and having a green density equivalent to that of a ring-shaped body, and sintered and aged under the same conditions as those for the ring-shaped body.

[0127] (Ring compression strength) The ring compression strength was determined as an index of the strength of the sintered body after aging treatment. The ring compression strength was determined in accordance with JIS Z 2507 standard.

[0128] (Results) The conductivity of the sintered body of Example 1 before aging treatment was 21%IACS, and the ring compression strength was 300 MPa.

[0129] The conductivity of Comparative Example 3 before aging treatment was 13%IACS, and the ring compression strength was 150 MPa. Also, the conductivity after aging treatment was 20%IACS, and the ring compression strength was 193 MPa.

[0130] Other results are shown in Table 1 and Table 2.

[0131]

Table 1

[0132]

Table 2

[0133] As shown in Table 1, the sintered density of the sintered body manufactured from the copper-based mixed powder in the present invention was all 7.2 g / cm 3In conclusion, it has been proven that even copper-based mixed powders containing Si, Ni, and / or Co, which exhibit poor sintering properties, can be sufficiently sintered by general sintering methods.

[0134] Furthermore, due to the improved sinterability, it was proven that sintered bodies with a Corson alloy composition that have undergone aging treatment exhibit an electrical conductivity in the range of 20.0%IACS to 40.0%IACS when X is Ni, and a compression ring strength of 400 MPa or more, achieving electrical conductivity and strength equivalent to that of conventionally molten Corson alloys.

[0135] Furthermore, it was proven that the same conductivity and strength as the molten material can be obtained when X is Co. [Industrial applicability]

[0136] The copper-based mixed powder in this invention contains Si, Ni, and / or Co, which are difficult to sinter, but has high sinterability. Therefore, a Cu-X-Si alloy with high strength and high electrical conductivity (thermal conductivity) can be manufactured using a general sintering method that allows for high mass production, similar to conventional copper powder and bronze powder. Furthermore, by adjusting the amount of Si, Ni, and / or Co contained in the copper-based mixed powder, and by aging the sintered body, it is possible to adjust the Cu-X-Si alloy to have even higher strength and higher electrical conductivity (thermal conductivity). Therefore, this copper-based mixed powder for powder metallurgy is suitable for use in sintered parts such as bearings and sliding parts where strength and heat dissipation are required. Therefore, the present invention is highly applicable to industry.

Claims

1. A copper-based mixed powder for powder metallurgy, wherein the copper-based mixed powder is obtained by mixing the following powder A and powder B, the Si content in the copper-based mixed powder is 0.2% by weight or more and 6.0% by weight or less in total, the Ni and / or Co content is 0.8% by weight or more and 40.0% by weight or less in total, and the apparent density is 4.0 g / cm³. ３ The following is a copper-based mixed powder for powder metallurgy, wherein 70% or more of the particles in the particle size distribution have a diameter of 106 μm or less. Powder A: An alloy powder containing 0.2% by weight or more and 6.0% by weight or less of Si, with the remainder being Cu and unavoidable impurities. Powder B: An alloy powder, mixed powder, or single-component powder containing 30.0% by weight or more of Ni and / or Co in total, with the remainder being Cu and unavoidable impurities.

2. The copper-based powder for powder metallurgy according to claim 1, wherein the aforementioned powder A and / or powder B contain one or more selected from the group consisting of Zn, Sn, Mg, and P, and the total amount of Zn, Sn, Mg, and P contained in the copper-based powder for powder metallurgy is 3.0% by weight or less.

3. A copper-based mixed powder for powder metallurgy according to claim 1 or 2, wherein a lubricant is added in an amount of 0.1% by weight or more and 1.0% by weight or less.

4. A method for producing a sintered body, comprising sintering a compacted molded body of a copper-based mixed powder for powder metallurgy according to any one of claims 1 to 3.

5. A method for producing a sintered body by further aging treatment of a sintered body produced by the manufacturing method described in claim 4.

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