JP2024065278A - Cu-based powder for infiltration - Google Patents

Abstract

To provide a Cu-based powder for infiltration, capable of producing an Fe-based alloy having high density due to its high infiltration rate, free from erosion on a surface of Fe-based base material, and not causing the Fe-based base materials to adhere to each other even if the Fe-based base materials are laminated and infiltrated because a residue is generated on the surface of Fe-based base materials after infiltration, wherein the residue generated can be easily removed.SOLUTION: A Cu-based powder for infiltration is a Cu-based powder comprising: 1.5 mass% to 4.0% mass of Fe or Co; and 0.3 mass% to 1.0 mass% of a substance A, wherein the substance A is: an oxide whose standard free energy of formation per mol of O2 in a temperature range of 1,373 K to 1,423 K is equal to or less than a standard free energy of formation of Cr2O3 and which shows a solid phase at temperatures of 1,423 K or less; or a nitride whose standard free energy of formation per mol of N2 in the above temperature range is equal to or less than the standard free energy of formation of Si3 N4 and which shows a solid phase at temperatures of 1,423 K or less.SELECTED DRAWING: None

Description

The present invention relates to a Cu-based powder for infiltration that can be used as an infiltration material for Fe-based substrates. More specifically, the infiltration material made of the Cu-based powder for infiltration has a high infiltration rate, so that a high-density Fe-based alloy can be produced, and there is no erosion of the Fe-based substrate surface. In addition, since residue is generated on the Fe-based substrate surface after infiltration, even if Fe-based substrates are stacked and infiltration treatment is performed, the Fe-based substrates do not adhere to each other, and the generated residue can be easily removed.

There is a constant demand for mechanical parts made of Fe-based alloys to have higher density, strength, and toughness.

As a method for densifying Fe-based alloys, a technique has been established in which Cu or a Cu alloy is infiltrated into a compact or sintered body of Fe-based metal powder (hereinafter referred to as the "Fe-based base material").

Infiltration is a technique in which a porous Fe-based base material is heated by contacting a compact of Cu or a Cu alloy (hereafter referred to as the "infiltration material"), which has a lower melting point than the Fe-based base material, with the Fe-based base material, and the infiltration material melts by heating and penetrates the Fe-based base material by capillary action, filling the pores inside the Fe-based base material and reducing the pores.

By reducing the number of pores, the density of the Fe-based base material increases, improving its compactness and enabling the Fe-based alloy to have higher strength and toughness.

In general, a high infiltration rate (the ratio of the weight of the infiltrant that has penetrated the substrate to the weight of the infiltrant in contact with the substrate) is required for the infiltrant.

In addition, if the Fe in the Fe-based substrate dissolves in the infiltrating material that it comes into contact with, the surface of the Fe-based substrate will become rough or dents will form (hereinafter referred to as "erosion"). Therefore, it is required that the Fe does not dissolve in the infiltrating material and does not erode the surface of the Fe-based substrate.

In addition, it is required that any residue on the surface of the Fe-based substrate after infiltration (hereinafter referred to as "residue") does not adhere to the Fe-based substrate and can be easily removed.

Patent Publication 2013-133518 Patent Publication No. 2009-7648

In order to meet the above requirements, the applicant has developed the Cu-based powder for infiltration disclosed in Patent Documents 1 and 2.

Patent Document 1 discloses a mixed powder for infiltration that contains 1.5% to 5.5% by mass of Fe, 1.0% to 2.5% by mass of Mn, 1.0% to 2.0% by mass of Zn, 0.01% to 0.1% by mass of Al, 0.1% to 0.6% by mass of Si, and the remainder is Cu.

Patent Document 2 discloses a powder for infiltration in which a raw material powder with a composition of Fe: 2% by mass to 7% by mass, Mn: 1% by mass to 7% by mass, Zn: 0.5% by mass to 5% by mass, Al: 0.03% by mass to 0.1% by mass, and the remainder Cu is mixed with 0.1% by mass to 1% by mass of an oxide of at least one of Al, Si, Zr, Ti, and Mg.

The Cu-based powder for infiltration described in Patent Documents 1 and 2 has a high infiltration rate and does not erode the surface of the Fe-based substrate, but depending on the conditions, the amount of residue may increase or decrease, or the residue may adhere to the Fe-based substrate.

The present inventors conducted numerous prototypes and experiments through trial and error in order to solve the above problems, and as a result, have found that the present invention provides an oxide which contains 1.5 mass % or more and 4.0 mass % or less of Fe or Co, 0.3 mass % or more and 1.0 mass % or less of substance A, with the remainder being Cu and unavoidable impurities, and which has a standard free energy of formation per 1 mol of O ₂ in the temperature range of 1373K to 1423K not more than the standard free energy of formation of Cr ₂ O ₃ per mol of O ₂ in said temperature range and is in a solid phase at temperatures not more than 1423K, or a standard free energy of formation per 1 mol of N ₂ in said temperature range not more than the standard free energy of formation of Si ₃ N ₂ per mol of N 2 in said temperature range. The present inventors have found that if a Cu-based powder for infiltration is a nitride in the solid phase at a temperature of 1423K or less and has a standard free energy of formation of ₄ or less, it is possible to manufacture an infiltration material that has a high infiltration rate and does not erode the surface of the Fe-based base material, and that generates a residue after infiltration, but the generated residue does not adhere to the Fe-based base material and can be easily removed, thereby achieving the above technical objective.

The above technical problems can be solved by the present invention as follows:

The present invention is a Cu-based powder for infiltration, the Cu-based powder containing 1.5 mass % or more and 4.0 mass % or less of Fe or Co, 0.3 mass % or more and 1.0 mass % or less of substance A, with the remainder being Cu and unavoidable impurities, and the substance A being an oxide in a solid phase at a temperature of 1423 K or less, the standard free energy of formation per 1 mol of O ₂ in a temperature range of 1373 K to 1423 K being equal to or less than the standard free energy of formation of Cr ₂ O ₃ per ₁ mol of O 2 in said temperature range, or a nitride in a solid phase at a temperature of 1423 K or less, the standard free energy of formation per ₁ mol of N ₂ in said temperature range being equal to or less than the standard free energy of formation of Si ₃ N ₄ per 1 mol of N 2 in said temperature range.

The present invention also relates to the above-mentioned Cu-based powder for infiltration, which contains 0.1 mass% or more and 2.0 mass% or less of Mn and/or 0.5 mass% or more and 3.0 mass% or less of Zn.

The present invention also relates to the above-mentioned Cu-based powder for infiltration, which contains 0.4 mass% or less of Si.

The present invention also relates to the above-mentioned Cu-based powder for infiltration, in which the powder has a lightness L value of 35 or more.

The present invention also relates to the above-mentioned Cu-based powder for infiltration, which contains 0.1% by mass or more and 1.0% by mass or less of a lubricant.

The present invention also relates to the above-mentioned Cu-based powder for infiltration that has been subjected to anti-rust treatment or anti-segregation treatment.

The present invention also relates to a method for producing the above-mentioned Cu-based powder for infiltration.

The present invention also relates to a compact of the above-mentioned Cu-based powder for infiltration.

The Cu-based powder for infiltration in the present invention contains at least 1.5 mass% and at most 4.0 mass% Fe or Co, which prevents erosion of the Fe-based substrate surface.

In addition, the Cu-based powder for infiltration in the present invention further contains 0.3 mass% or more and 1.0 mass% or less of substance A, so that the infiltration rate is high, and after infiltration, a residue is generated, which becomes an infiltration material that can be easily removed.

The infiltration material produced from the Cu-based infiltration powder of the present invention has a high infiltration rate and can densify the Fe-based base material, making it possible to produce sintered Fe-based alloy parts that are high in strength and toughness.

In addition, since residues are generated after infiltration, even if Fe-based substrates are stacked and infiltrated, they are unlikely to adhere to each other, and the generated residues can be easily removed.

Since the Fe-based base material can be layered and then infiltrated, it is expected that the production volume of sintered parts per unit time can be improved.

Furthermore, if the material contains 0.1 mass% or more and 2.0 mass% or less of Mn and/or 0.5 mass% or more and 3.0 mass% or less of Zn, the material will have even higher wettability and infiltration rate.

In addition, if the powder's lightness L value is 35 or more, the amount of oxygen in the Cu-based powder for infiltration is low, and the decrease in wettability caused by oxidation can be suppressed, resulting in an infiltration material with good wettability.

In addition, if the lubricant content is 0.1 mass% or more and 1.0 mass% or less, the lubricity is improved, resulting in a Cu-based powder for infiltration that is easy to mold.

In addition, by performing rust prevention or segregation prevention treatment, the dispersibility of each component of the Cu-based powder for infiltration is improved, which further suppresses the generation of excess residue and the adhesion of the generated residue.

In general, infiltration of Cu-based powder into Fe-based base materials is carried out in the temperature range of 1373K to 1423K (hereinafter referred to as the "infiltration temperature range"), which is higher than the peritectic temperature of Cu-Fe binary alloys.

The saturated solubility of Fe (iron) in Cu at the infiltration temperature range is approximately 4.5 mass%.

When an Fe-based substrate is infiltrated with Cu alone, the Fe in the substrate dissolves into the infiltrating material, which can cause erosion of the Fe-based substrate surface, resulting in depressions and a rough surface. However, the Cu-based powder for infiltration in this invention contains Fe or Co and substance A, with the remainder consisting of Cu and unavoidable impurities, so it is possible to prevent erosion of the Fe-based substrate surface.

The Fe content in the Cu-based powder for infiltration is preferably 1.5% by mass or more and 4.0% by mass or less, and more preferably 2.0% by mass or more and 3.5% by mass or less.

If the content is less than 1.5% by mass, the corrosion prevention effect is weak, and if the content exceeds 4.0% by mass, Fe does not completely dissolve in the infiltrating material at the infiltration temperature range, leaving residue that may adhere to the surface of the Fe-based substrate.

The form of Fe is not particularly limited and may be any of a simple powder, an alloy powder, or a partially alloyed powder, with alloy powder or partially alloyed powder being preferred.

This is because the elemental powder may be difficult to diffuse into Cu depending on the infiltration conditions.

The Cu-based powder for infiltration in the present invention may contain Co instead of Fe.

Like Fe, Co dissolves in Cu and can prevent erosion and roughening of the surface of Fe-based substrates.

The Co content, like Fe, is preferably 1.5% by mass or more and 4.0% by mass or less, and more preferably 2.0% by mass or more and 3.5% by mass or less.

If it is less than 1.5% by mass, the erosion prevention effect is weak, and if it exceeds 4.0% by mass, Co does not completely dissolve in the infiltrating material at the infiltration temperature range, leaving residue that may adhere to the surface of the Fe-based base material.

The form of Co is not particularly limited and may be any of a simple powder, alloy powder, or partially alloyed powder, with alloy powder or partially alloyed powder being preferred.

This is because the elemental powder does not easily diffuse into Cu at the infiltration temperature range.

The Cu-based powder for infiltration in this invention contains substance A.

Substance A is a substance that is not easily reduced in an atmosphere containing hydrogen with a dew point of approximately -30°C (hereinafter referred to as "normal infiltration atmosphere"), and is a solid-phase oxide or nitride at temperatures below 1423K.

When substance A becomes liquid, it may cause erosion of the surface of the Fe-based substrate, or residue may adhere to the surface of the Fe-based substrate, making it difficult to remove.

If it is a solid phase, residues will be generated on the surface of the Fe-based substrate, making it difficult for the Fe-based substrates to adhere to each other even if the Fe-based substrates are stacked and infiltrated.

The production efficiency of sintered parts can be improved by stacking and performing the infiltration process.

In addition, any residue that is produced can be easily removed.

Specifically, the substance A in the present invention is an oxide having a standard free energy of formation per mol of _O2 (oxygen) in the infiltration temperature range equal to or less than the standard free energy of formation _{of Cr2O3} (chromium oxide) per mol of _O2 in the infiltration temperature range, and is a solid-phase oxide at temperatures of 1423K or less.

Oxides such as Ag (silver), Bi (bismuth), Ni (nickel), Sn (tin), In (indium), and P (phosphorus) that have a standard free energy of formation per 1 mol of _O2 in the infiltration temperature range greater than the standard free energy of formation of _Cr2O3 per 1 mol of _O2 in the infiltration temperature range are easily reduced in _a normal infiltration atmosphere, and may react with the infiltration material or the Fe-based base material, causing adhesion between the laminated Fe-based base materials or eroding the surface of the Fe-based base material.

The substance A in the present invention may be a nitride having a standard free energy of formation per mole of _N2 (nitrogen) in the infiltration temperature range equal to or less than the standard free energy of formation of _Si3N4 (silicon nitride) per mole of _N2 in the infiltration temperature range, and may be a solid-phase nitride at temperatures equal to _or less than 1423K.

Nitrides such as Ga (gallium) and In (indium) nitrides, which have a standard free energy of formation per 1 mol of _N2 in the infiltration temperature range that is greater than the standard free energy of formation _{of Si3N4} in the infiltration temperature range, have a positive standard free energy of formation in the infiltration temperature range, and depending on the nitrogen partial pressure in the system, the nitrides may decompose, etc., and the residue may adhere to the surface of the Fe-based substrate.

Examples of material A include _{Cr2O3 (} chromium oxide _{), SiO2 (silicon oxide), TiO2 (titanium oxide), Al2O3 ( aluminum oxide} ), MgO (magnesium oxide), _ZrO2 (zirconium oxide) _{, Si3N4} (silicon nitride), BN (boron nitride), and ZrN (zirconium nitride).

Values for the standard free energy of formation of oxide per mole of O ₂ or nitride per mole of N ₂ in the infiltration temperature range can be obtained from the literature.

The content of substance A in the Cu-based powder for infiltration is 0.3% by mass or more and 1.0% by mass or less, and more preferably 0.4% by mass or more and 0.9% by mass or less.

If the content is less than 0.3% by mass, there will be little residue after infiltration, and if multiple Fe-based substrates and infiltration materials are stacked and infiltration treatment is performed, there is a risk that the Fe-based substrates will adhere to each other. Also, if the content exceeds 1.0% by mass, there is a risk that the wettability of the infiltration material will decrease, resulting in a decrease in the infiltration rate.

Substance A may be a mixture of oxides, a mixture of nitrides, or a mixture of oxides and nitrides.

The Cu-based powder for infiltration in the present invention may contain 0.1% by mass or more and 2.0% by mass or less of Mn (manganese) and/or 0.5% by mass or more and 3.0% by mass or less of Zn (zinc).

Mn dissolves in both Fe and Cu, improving the wettability of the infiltrant and the Fe-based base material and increasing the infiltration rate, so even if substance A, which reduces wettability, is included, the wettability and infiltration rate are unlikely to decrease.

The Mn content is preferably 0.1% by mass or more and 2.0% by mass or less, and more preferably 0.3% by mass or more and 0.8% by mass or less.

If the Mn content is less than 0.1 mass%, no improvement in wettability or infiltration rate will be observed, and if it exceeds 2.0 mass%, Mn oxides may be generated, Mn may dissolve in the Fe-based base material or Fe in the infiltrant, causing corrosion of the Fe-based base material surface, or residues may adhere.

Zn has the effect of lowering the melting point of the infiltrant, and also improves the wettability of the infiltrant with the Fe-based base material, improving the infiltration rate, so even if substance A, which reduces wettability, is included, the wettability and infiltration rate are unlikely to decrease.

The Zn content is preferably 0.5% by mass or more and 3.0% by mass or less, and more preferably 0.5% by mass or more and 2.0% by mass or less.

If the Zn content is less than 0.5% by mass, no improvement in wettability is observed, and if it exceeds 3.0% by mass, the amount of Zn that evaporates during the infiltration process increases, resulting in a poor yield of the infiltration material and a decrease in the infiltration rate.

In addition, evaporated Zn may contaminate the sintering furnace.

The Cu-based powder for infiltration in the present invention may contain 0.4 mass% or less of Si (metallic silicon).

A small amount of Si dissolves in the infiltrating material and inhibits sintering between the infiltrating materials, allowing the amount and size of the residue to be adjusted.

The Si content is preferably 0.4 mass% or less, and more preferably 0.05 mass% or more and 0.1 mass% or less.

If the Si content exceeds 0.4 mass%, there is a risk of the infiltration rate decreasing.

In the present invention, it is preferable that the Cu-based powder for infiltration has an L value, which is the lightness of the powder, of 35 or more.

The upper limit of the content of substance A is set to 1.0 mass% or less because it reduces the wettability of the infiltrating material and the Fe-based base material. However, if the wettability is reduced due to factors other than substance A, such as an increase in the amount of oxygen in the Cu-based powder for infiltration due to changes over time, this can result in an unintentionally low infiltration rate and reduced strength of the sintered part.

If the L value, which is the brightness of the powder, is 35 or more, it can be estimated that the amount of oxygen is low even if it is difficult to measure the amount of oxygen contained in substances other than substance A, and the decrease in wettability caused by oxidation of the Cu-based powder for infiltration can be suppressed.

A lubricant can be added to the Cu-based powder for infiltration in the present invention.

The addition of a lubricant improves lubricity, resulting in a Cu-based powder for infiltration that is easy to mold.

The amount of lubricant added is preferably 0.1% by mass or more and 1.0% by mass or less, and more preferably 0.2% by mass or more and 0.8% by mass or less.

If the amount is less than 0.1% by mass, the effect of improving lubricity is weak, and even if more than 1.0% by mass is added, the amount of lubricant that evaporates increases, the yield of the infiltrating material decreases, and the infiltration rate decreases.

In addition, evaporated lubricant may contaminate the sintering furnace.

The lubricant is not particularly limited, but metal soaps such as zinc stearate and EBS-based waxes are suitable.

Anti-rust treatment or anti-segregation treatment can be applied to some or all of the powders that make up the Cu-based powder for infiltration.

Segregation that occurs in Cu-based powders for infiltration includes accumulation segregation caused by differences in the fluidity of the powders mixed together.

The flowability of a powder can change due to oxidation of the powder surface, and even if there is no segregation when it is first manufactured, segregation may become noticeable in a relatively short period of time depending on the storage environment.

If segregation occurs in the Cu-based powder for infiltration in the present invention, the mass ratio between substance A and other infiltration material components will vary locally, and there is a risk that residue will adhere or excessive residue will be generated.

By subjecting some or all of the powders that make up the Cu-based powder for infiltration to rust prevention or segregation prevention treatment, segregation can be prevented overall, and the adhesion of residues or the generation of excessive residues can be suppressed.

In addition, anti-rust treatment can suppress not only segregation but also the generation of residues due to oxidation.

There are no particular limitations on the rust prevention treatment, and an organic compound containing one or more elements that coordinate with Cu per molecule can be used, and preferably the organic compound has 3 to 30 carbon atoms.

There are no particular limitations on the segregation prevention treatment, and examples include surface modification treatments that reduce fluidity, such as reducing the specific surface area by granulating the powder or reducing oxide-containing powder to make it porous, and the addition of various functional groups by chemical reactions with organic compounds, such as the addition of machine oil or binders, or physical adsorption.

Benzotriazole and machine oil can be used for rust prevention and segregation prevention treatment.

The Cu-based powder for infiltration in the present invention can be produced by mixing Fe or Co with a simple powder, alloy powder, or partially alloyed powder of material A or other elements.

The method for producing the powder of Fe or Co and substance A or other elements is not particularly limited, and they may be produced by known methods such as atomization, reduction, electrolysis, and pulverization.

The average particle size of powders other than substance A constituting the present invention is preferably 1 μm or more and 300 μm or less.

Particles with an average particle size of more than 300 μm may not mix uniformly and may cause the components to segregate, while particles with an average particle size of less than 1 μm are difficult to handle and the powder is expensive.

The average particle size of substance A is preferably 300 μm or less, and more preferably 3 μm or less.

This is because particles with an average particle size of more than 300 μm will not mix uniformly and there is a risk of the components segregating.

The Cu-based powder for infiltration in the present invention can be formed into an infiltration material by known methods such as powder compaction.

There are two types of infiltration methods for infiltrating an Fe-based base material with an infiltrant: the one-step infiltration method, in which the Fe-based base material and the infiltrant are brought into contact with each other and heated to simultaneously perform sintering and infiltration; and the two-step infiltration method, in which the Fe-based base material is first heated to pre-sinter, and then the infiltrant is brought into contact with the sintered body and heated a second time to perform infiltration.

The infiltration material made of the Cu-based powder for infiltration in this invention has a high infiltration rate, so it becomes a high-density Fe-based alloy not only in the two-step infiltration method but also in the one-step infiltration method, making it possible to manufacture sintered parts that are high in strength and high in toughness.

Examples and comparative examples of the present invention are shown below, but the present invention is not limited to these.

<Fe-based substrate>
Electrolytic Cu powder, graphite powder, and atomized Fe powder were mixed to a content of 1.5 mass% Cu, 1.0 mass% C, and the remainder Fe, and then 13.7 g of the mixed powder to which 0.8 mass% zinc stearate had been added was molded into a compressed powder body having a width of 12 mm, length of 30 mm, and thickness of 6 mm and a density of 6.3 g/ ^cm3 to produce an Fe-based base material.

<Cu-based powder for infiltration>
(Production of metal powder)
(a) In a sulfuric acid acid bath, a direct current is passed through Cu ingot to cause Cu to deposit on a cathode plate, which is then recovered, washed, and dried to obtain Cu powder. Cu powder produced by an electrolytic method is sieved to 200 mesh or smaller to produce Cu powder.
(b) The alloy components in a molten state, adjusted to have the composition (mass%) shown in Table 1, were dropped into high-pressure water of about 15 MPa and rapidly solidified by a water atomization method, and the Cu-based alloy or Fe powder thus produced was sieved to 200 mesh or less to produce the Cu-based alloy or Fe powder.
(c) Mn or Si ingot was crushed and sieved to 200 mesh or less to prepare Mn or Si powder.

(Substance A)
Table 1 shows the standard free energy of formation per 1 mol of O ₂ for Cr ₂ O ₃ and substance A (oxide) at 1,400 K, and Table 2 shows the standard free energy of formation per 1 mol of N ₂ for Si ₃ N ₄ and substance A (nitride) at 1,400 K.

(Production of Cu-based powder for infiltration)
In Examples 20 to 27, Cu-based alloy powder (B) and Mn powder (C), in Examples 29 and 30, Cu-based alloy powder (B) and Si powder (C), in Example 34, Cu powder (A) and Fe powder (B), and in the other Examples, Comparative Examples, and Reference Examples, only Cu-based alloy powder (B) was used.

The metal powders (a) to (c) were mixed in a rocking mixer so that the overall composition (mass%) was as shown in Table 3. The elements contained were quantified using an ICP optical emission spectrometer iCAP7600 (manufactured by Thermo Fisher Scientific Co., Ltd.), and then substance A was added in the proportion (mass%) shown in Table 3 and 0.5 mass% zinc stearate was added as a lubricant. The mixture was mixed again in a rocking mixer to produce each Cu-based powder for infiltration.

The lightness L value of the powder surface was measured using a spectrophotometer SE6000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

<Infiltration method>
An infiltration material was prepared by pressing Cu-based powder for infiltration in an amount of 80 volume % relative to the pores of the Fe-based base material into a thin plate shape of 12 mm width x 30 mm length x 1 mm thickness.

The infiltration material was placed on the compact of the Fe-based base material and infiltration was performed using the one-step infiltration method.

The infiltration conditions were heating at 823K for 30 minutes to dewax the lubricant in the infiltrant, and then heating at 1403K for 30 minutes.

The atmosphere inside the sintering furnace was a mixed gas atmosphere of hydrogen:nitrogen at a ratio of 3:1.

<Infiltration rate>
The infiltration rate was calculated based on the following equation 1.

<Residue removal>
The presence or absence of residue and removability were confirmed.

Those where residue was found and could be easily removed by hand were rated as "good", those that could not be removed by hand were rated as "stuck", and those where no residue was found were rated as "no residue".

EROSION
The presence or absence of erosion was confirmed by observation under an optical microscope (magnification: 50 times) and by visual inspection.
Cases where erosion was confirmed were rated as "present," and cases where erosion was not confirmed were rated as "absent."

The results for each example are shown in Table 3, and the results for each comparative example are shown in Table 4.

As shown in Examples 1 to 35, the infiltration material made of the Cu-based powder for infiltration according to this embodiment has a higher infiltration rate than the infiltration materials shown in Comparative Examples 1 to 9, there is no erosion of the Fe-based substrate surface after infiltration, and the generated residue can be easily removed.

In Comparative Example 5, since substance A was not included, no residue was generated.
In Comparative Example 6, since the content of substance A was less than 0.3 mass %, no residue was generated.
In Comparative Example 7, the content of substance A was more than 1.0 mass %, so the wettability of the infiltrant decreased, and the infiltration rate decreased.
In Comparative Example 8, FeO selected as material A was reduced during the infiltration process and reacted with the Fe-based base material, resulting in the deposition of residue.
In Comparative Example 9, GaN selected as material A was partially decomposed during the infiltration process and reacted with the Fe-based base material, resulting in the deposition of residue.

The Cu-based powder for infiltration in the present invention has a high infiltration rate and therefore becomes a high density Fe-based alloy, making it possible to manufacture sintered parts with high strength and toughness.
Furthermore, there is no erosion of the surface of the Fe-based base material after the infiltration treatment.
In addition, since residues are generated on the surface of the Fe-based base material, even if the Fe-based base materials are stacked and infiltrated, the Fe-based base materials do not adhere to each other, and the generated residues can be easily removed, so that the Cu-based powder for infiltration serves as an infiltration material with excellent productivity for sintered parts.
Therefore, the present invention has high industrial applicability.

Claims (8)

A Cu-based powder for infiltration, comprising:
A Cu-based powder for infiltration comprising 1.5 mass % or more and 4.0 mass % or less of Fe or Co, 0.3 mass % or more and 1.0 mass % or less of substance A, with the remainder being Cu and unavoidable impurities, said substance A being an oxide in a solid phase at a temperature of 1423 K _{or less, the standard free energy of formation per 1 mol of O 2 in} a temperature range of 1373 K to 1423 K being equal to or less than the standard free energy of formation of Cr ₂ O ₃ per 1 mol of O ₂ in said temperature range, or a nitride in a solid phase at a temperature of 1423 K or less, the standard free energy of formation per 1 mol of N ₂ in said temperature range being equal to or less than the standard free energy of formation of Si ₃ N ₄ per 1 mol of N 2 in said temperature range. The Cu-based powder for infiltration according to claim 1, containing 0.1 mass% or more and 2.0 mass% or less of Mn and/or 0.5 mass% or more and 3.0 mass% or less of Zn. Cu-based powder for infiltration according to claim 1 or 2, containing 0.4 mass% or less of Si. Cu-based powder for infiltration according to claim 1 or 2, in which the powder has a lightness L value of 35 or more. The Cu-based powder for infiltration according to claim 1 or 2, containing 0.1 mass% or more and 1.0 mass% or less of a lubricant. Cu-based powder for infiltration according to claim 1 or 2, which has been subjected to anti-rust treatment or anti-segregation treatment. A method for producing the Cu-based powder for infiltration according to claim 1 or 2. 3. A powder compact of the Cu-based powder for infiltration according to claim 1 or 2.