WO2017022578A1 - Powder for conductive fillers - Google Patents

Powder for conductive fillers Download PDF

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Publication number
WO2017022578A1
WO2017022578A1 PCT/JP2016/071925 JP2016071925W WO2017022578A1 WO 2017022578 A1 WO2017022578 A1 WO 2017022578A1 JP 2016071925 W JP2016071925 W JP 2016071925W WO 2017022578 A1 WO2017022578 A1 WO 2017022578A1
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mass
phase
cubi
powder
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PCT/JP2016/071925
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French (fr)
Japanese (ja)
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哲嗣 久世
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山陽特殊製鋼株式会社
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/02—Alloys based on copper with tin as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/04—Alloys based on copper with zinc as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/08—Alloys based on copper with lead as the next major constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying

Definitions

  • the present invention relates to a powder suitable for a conductive filler used in a conductive resin, a conductive adhesive, a conductive paste, an electronic device, an electronic component, and the like.
  • An alloy powder containing copper as a main component is known as a filler contained in a conductive substance. Since the electrical resistance of copper is small, the filler containing copper is excellent in conductivity. Since a large contact area between the particles can be obtained by aggregation of the copper particles, copper also contributes to the conductivity of the filler from this viewpoint. Furthermore, copper is excellent in thermal conductivity.
  • Copper is easy to oxidize. In other words, copper tends to react with oxygen in the atmosphere. This reaction produces an oxide film. This oxide film inhibits conductivity.
  • a filler made of an alloy containing copper as a main component requires a surface treatment such as an antioxidant treatment or an oxide film removal treatment.
  • JP-A-2015-74806 discloses a conductive filler made of an alloy containing Cu and 1 to 30% by mass of Ag. In this filler, an AgCu phase having a high Ag concentration is present on the surface layer of the particles.
  • Japanese Patent Laid-Open No. 5-114305 discloses a powder made of an Ag—Cu alloy. This powder contains Bi, Zn or Pb. Bi, Zn and Pb have low melting points.
  • JP 2013-163185 discloses a filler made of a Cu—Bi alloy. This filler contains 50 to 99% by mass of Cu and 1 to 50% by mass of Bi.
  • JP 2014-28380 A discloses a filler made of a Cu-Bi alloy. This filler contains Cu and 1 to 50% by mass of Bi.
  • JP-A-2015-74806 Japanese Patent Laid-Open No. 5-114305 JP2013-163185A JP 2014-28380 A
  • the surface of Cu is surface-treated with an organic solvent. This surface treatment takes time and effort. The production cost of this powder is high. It is not easy to achieve both conductivity and low cost.
  • An object of the present invention is to provide a conductive filler powder that is excellent in conductivity and can be obtained at low cost.
  • the conductive filler powder according to the present invention comprises a plurality of particles.
  • the material of each particle is an alloy containing 0.1 mass% or more and 10 mass% or less of Bi, with the balance being Cu and inevitable impurities.
  • This alloy includes a first CuBi phase satisfying the following formula (1) and a second CuBi phase satisfying the following formula (2).
  • This particle has a surface layer portion having a thickness of 100 nm.
  • the ratio P1 of the first CuBi phase in the surface layer portion is 5% by mass or more. 0.010 ⁇ x / y ⁇ 1 (1) 0 ⁇ x / y ⁇ 0.005 (2)
  • x represents the mass content of Bi
  • y represents the mass content of Cu.
  • the conductive filler powder according to the present invention comprises a plurality of particles.
  • the material of each particle is an alloy containing 0.1 mass% or more and 10 mass% or less of Bi and the element X1, with the balance being Cu and inevitable impurities.
  • This element X1 is one or more selected from the group consisting of Sn, In, Zn, Ga and Pb.
  • This alloy includes a first CuBi phase satisfying the following formula (1) and a second CuBi phase satisfying the following formula (2).
  • This particle has a surface layer portion having a thickness of 100 nm. The ratio P1 of the first CuBi phase in the surface layer portion is 5% by mass or more.
  • x represents the mass content of Bi
  • y represents the mass content of Cu.
  • the content rate of the element X1 is 1 mass% or more and 10 mass% or less.
  • the cumulative 50 volume% particle diameter (D 50 ) of the powder is 1 ⁇ m or more and 10 ⁇ m or less.
  • the conductive filler powder according to the present invention contains Cu, it is excellent in conductivity.
  • the production of this powder does not require surface treatment such as coating. Therefore, it takes less time to produce this powder. This powder can be obtained at low cost.
  • FIG. 1 is a schematic cross-sectional view showing particles contained in a powder according to an embodiment of the present invention.
  • FIG. 2 is an enlarged view of a portion indicated by an arrow II in FIG.
  • FIG. 3 is an enlarged view of a portion indicated by an arrow III in FIG.
  • the conductive filler powder according to the present invention is a collection of a large number of particles.
  • FIG. 1 shows an enlarged cross section of the particle 2.
  • the material of the particles 2 is an alloy. This alloy contains Cu and Bi.
  • the alloy is (1) Cu (2) Bi and (3) Contains only inevitable impurities.
  • this alloy has a Cu phase 4, a Bi phase 6, a first CuBi phase 8, and a second CuBi phase 10.
  • the Bi phase 6, the first CuBi phase 8, and the second CuBi phase 10 are dispersed and precipitated in the Cu phase 4.
  • the main component of the Cu phase 4 is Cu.
  • the Cu phase 4 may contain only Cu.
  • the Cu phase 4 may contain a small amount of other elements together with Cu.
  • the ratio of Cu in the Cu phase 4 is 90% by mass or more.
  • Cu is conductive.
  • Bi phase 6 The main component of Bi phase 6 is Bi.
  • Bi phase 6 may contain only Bi.
  • the Bi phase 6 may contain a small amount of other elements together with Bi.
  • the ratio of Bi in the Bi phase 6 is 90% by mass or more.
  • the conductivity of Bi is low.
  • the first CuBi phase 8 contains Cu and Bi.
  • the first CuBi phase 8 can include a compound of Cu and Bi.
  • the first CuBi phase 8 satisfies the following mathematical formula (1). 0.010 ⁇ x / y ⁇ 1 (1)
  • x represents the mass content of Bi
  • y represents the mass content of Cu.
  • the Bi content x in the first CuBi phase 8 is relatively large. In other words, Bi is concentrated in the first CuBi phase 8. Therefore, the conductivity of the first CuBi phase 8 is small.
  • the second CuBi phase 10 contains Cu and Bi.
  • the second CuBi phase 10 can contain a compound of Cu and Bi.
  • the second CuBi phase 10 satisfies the following mathematical formula (2). 0 ⁇ x / y ⁇ 0.005 (2)
  • x represents the mass content of Bi
  • y represents the mass content of Cu.
  • the Bi content x in the second CuBi phase 10 is relatively small.
  • the Cu content is relatively large. In other words, Cu is concentrated in the second CuBi phase 10. Therefore, this second CuBi phase 10 is excellent in conductivity.
  • a boundary line L is a boundary line.
  • the boundary line L is a virtual line, and in practice, the boundary line L cannot be visually recognized in the particle 2.
  • the particle 2 is partitioned into the surface layer portion 12 and the core 14 by the boundary line L.
  • the thickness T (see FIG. 2) of the surface layer portion 12 is 100 nm.
  • the first CuBi phase 8 is mainly present in the surface layer portion 12. As described above, the Bi content x in the first CuBi phase 8 is large. Since the first CuBi phase 8 exists in the surface layer portion 12, the reaction of Cu in the Cu phase 4 of the core 14 with oxygen in the atmosphere can be suppressed. Furthermore, the reaction of Cu in the second CuBi phase 10 of the core 14 with oxygen in the atmosphere can also be suppressed. The first CuBi phase 8 can suppress the deterioration of the conductivity of the powder over time.
  • the melting point of the first CuBi phase 8 is low.
  • this powder is used in, for example, a conductive paste and heated, the fine eutectic structure of the first CuBi phase 8 melts at a relatively low temperature (for example, 250 to 600 ° C.). The fine eutectic structure disappears by cooling after melting.
  • Bi When the fine eutectic structure disappears, Bi aggregates to form a pure Bi phase. Bi has a low melting point. Bi atoms in the pure Bi phase cause metal bonds between the particles 2 by diffusion. This metal bond reduces the contact resistance between the particles 2. The product after cooling is excellent in conductivity.
  • the first CuBi phase 8 is mainly present in the surface layer portion 12. Therefore, the pure Bi phase formed by the disappearance of the fine eutectic structure is also mainly present in the surface layer portion 12.
  • all or part of the core 14 is covered with Bi. Therefore, the oxidation of Cu existing in the core 14 is suppressed. By suppressing oxidation, deterioration of electrical conductivity over time is suppressed.
  • the ratio P1 of the first CuBi phase 8 in the surface layer portion 12 is preferably 5% by mass or more, more preferably 6% by mass or more, and particularly preferably 7% by mass or more.
  • the ratio P1 is preferably 10% by mass or less.
  • the second CuBi phase 10 is mainly present in the core 14.
  • the second CuBi phase 10 contains a large amount of Cu. This Cu hardly reacts with oxygen in the atmosphere. In this particle 2, deterioration with time of electric conductivity is suppressed.
  • Bi of the second CuBi phase 10 suppresses electromigration. Therefore, in this particle 2, deterioration with time of electric conductivity is suppressed.
  • the first CuBi phase 8 satisfies the above formula (1).
  • the ratio (x / y) in the first CuBi phase 8 is not less than 0.010 and not more than 1.
  • the first CuBi phase 8 having a ratio (x / y) of 0.010 or more suppresses deterioration of electrical conductivity over time.
  • the ratio (x / y) is more preferably 0.10 or more, and particularly preferably 0.20 or more.
  • the first CuBi phase 8 having a ratio (x / y) of 1 or less is unlikely to hinder the conductivity of the powder.
  • the ratio (x / y) is more preferably equal to or less than 0.50, and particularly preferably equal to or less than 0.30.
  • the second CuBi phase 10 satisfies the above mathematical formula (2).
  • the ratio (x / y) in the second CuBi phase 10 is more than 0 and 0.005 or less.
  • the ratio (x / y) is more preferably equal to or greater than 0.0005, and particularly preferably equal to or greater than 0.001.
  • the second CuBi phase 10 having a ratio (x / y) of 0.005 or less is excellent in conductivity.
  • the ratio (x / y) is more preferably equal to or less than 0.003, and particularly preferably equal to or less than 0.002.
  • the amount of Bi in the alloy is preferably 0.1% by mass or more and 10% by mass or less. In an alloy having this amount of 0.1% by mass or more, electromigration is suppressed. In an alloy in which this amount is 0.1% by mass or more, deterioration of electric conductivity with time is suppressed. From these viewpoints, this amount is more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more. In an alloy having this amount of 10% by mass or less, there is little conductivity inhibition by Bi. In this respect, the amount is more preferably equal to or less than 7% by weight, and particularly preferably equal to or less than 5% by weight.
  • the amount of Cu in the alloy is preferably 90% by mass or more, more preferably 92% by mass or more, and particularly preferably 94% by mass or more.
  • the ratio of each element is determined by analysis of the FE-SEM image. Ratios are determined at 20 randomly extracted points and the average is calculated.
  • the cumulative 50 volume% particle diameter (D 50 ) of the powder is preferably 15 ⁇ m or less, more preferably 12 m or less, and particularly preferably 10 ⁇ m or less. From the viewpoint that aggregation of the powder can be suppressed, the particle diameter (D 50 ) is preferably 1 ⁇ m or more, more preferably 3 ⁇ m or more, and particularly preferably 4 ⁇ m or more.
  • the particle diameter (D 50 ) is the particle diameter at which the cumulative curve becomes 50% when the cumulative curve is obtained with the total volume of the powder as 100%.
  • the particle diameter (D 50 ) is measured by a laser diffraction / scattering particle size distribution measuring apparatus “Microtrack MT3000” manufactured by Nikkiso Co., Ltd. Powder is poured into the cell of this apparatus together with pure water, and the particle diameter (D 50 ) is detected based on the light scattering information of the particles 2. An average value of 10 measurements is calculated.
  • the melting point of the Cu—Bi alloy is lower than the melting point of Cu.
  • the viscosity of the molten Cu—Bi alloy is lower than the viscosity of the molten Cu. From this alloy, fine powder can be easily obtained by atomization. The reason is, (1) It is not necessary to prepare a high-temperature molten metal (2) The atomizing injection pressure does not need to be high, and (3) It is not necessary to employ a fine injection nozzle.
  • the alloy may further include an element X1.
  • the element X1 is one or more selected from the group consisting of Sn, In, Zn, Ga, and Pb.
  • the alloy is (1) Cu (2) Bi (3) Element X1 and (4) Contains only inevitable impurities.
  • the melting point of the alloy containing the element X1 is low.
  • the viscosity of the molten alloy is low. From this alloy, fine powder can be easily obtained by atomization. The reason is, (1) It is not necessary to prepare a high-temperature molten metal (2) The atomizing injection pressure does not need to be high, and (3) It is not necessary to employ a fine injection nozzle.
  • the content of the element X1 in the alloy is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 3% by mass or more. From the viewpoint of conductivity, the content is preferably 10% by mass or less.
  • the Bi content is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more. This content is preferably 10% by mass or less, more preferably 7% by mass or less, and particularly preferably 5% by mass or less.
  • Electrical conductivity of the powder is preferably 500AV -1 m -1 or more, more preferably 700AV -1 m -1 or more, 1000AV -1 m -1 or more are particularly preferred.
  • the powder having high electrical conductivity has a small electrical resistance value.
  • the electric resistance of the powder includes a contact resistance generated between the particles 2 in contact with each other and a bulk resistance generated inside the particles 2. In the powder according to the present invention, excellent conductivity is achieved by a small contact resistance.
  • the powder according to the present invention can be obtained by atomization.
  • the characteristics of the powder depend not only on the material but also on the atomization cooling rate.
  • a gas atomizing method, a disk atomizing method, a water atomizing method, or the like can be employed. From the viewpoint of easily obtaining a powder having a small particle size, the gas atomizing method and the disk atomizing method are preferable. In the production of this powder, no coating process is required. The production cost of this powder is low.
  • raw materials are put into a quartz crucible having pores at the bottom. This raw material is heated and melted by a high frequency induction furnace in an argon gas atmosphere. In an argon gas atmosphere, argon gas is injected onto the raw material flowing out from the pores. The raw material is rapidly cooled and solidified to obtain a powder.
  • the coagulation rate can be controlled by adjusting the injection pressure. The greater the injection pressure, the greater the solidification rate. By controlling the solidification rate, a powder having a desired particle size distribution can be obtained. The faster the solidification rate, the smaller the width of the particle size distribution.
  • raw materials are put into a quartz crucible having pores at the bottom. This raw material is heated and melted by a high frequency induction furnace in an argon gas atmosphere. In an argon gas atmosphere, the raw material flowing out from the pores is dropped onto a disk that rotates at high speed. The rotation speed is 40000 rpm to 60000 rpm. The raw material is rapidly cooled by the disk and solidified to obtain a powder. This powder may be milled.
  • each powder was measured. First, particles having a diameter exceeding 45 ⁇ m were removed from the powder using a sieve. This powder was filled into a cylindrical sample holder (four-terminal sample holder for powder impedance measurement by Toyo Technica Co., Ltd.) having a diameter of 25 mm and a height of 10 mm. A load of 4 Nm was applied to the powder from above and below. A positive terminal for current and a positive terminal for voltage were attached to the upper side of the powder. A negative terminal for current and a negative terminal for voltage were attached to the lower side of the powder. The voltage was measured by applying a current by the so-called four-terminal method. The results are shown in Tables 1 and 2 below.
  • each powder is rated with an AD rating.
  • the criteria for this evaluation are as follows. Rating A Particle diameter (D 50 ): 1 ⁇ m or more and 10 ⁇ m or less Electrical conductivity: 1000 AV ⁇ 1 m ⁇ 1 or more Rating B Particle size (D 50 ): 10 ⁇ m or more Electrical conductivity: 1000 AV ⁇ 1 m ⁇ 1 or more Rating C Particle diameter (D 50): 1 [mu] m or more 10 ⁇ m or less electrical conductivity: 500AV -1 m -1 or more 1000AV -1 m less than -1 rating D Particle diameter (D 50 ): 1 ⁇ m or more and 10 ⁇ m or less Electric conductivity: less than 500 AV ⁇ 1 m ⁇ 1
  • the rating of each comparative example shown in Table 2 is E.
  • This powder (1) The composition is out of the scope of the present invention (2)
  • the formula (1) is not satisfied (3)
  • the formula (2) is not satisfied and
  • the ratio P1 is out of the scope of the present invention Applicable.
  • the powder according to Example 7 has a structure of 99Cu-1Bi.
  • the ratio (x / y) in the first CuBi phase is 0.22, which satisfies Expression (1).
  • X / y in the second CuBi phase is 0.0020, which satisfies Expression (2).
  • the ratio P1 of the first CuBi phase in the surface layer portion is 7.4%.
  • the particle diameter (D 50 ) is 8.7 ⁇ m, and the electric conductivity is 1380AV ⁇ 1 m ⁇ 1 . This powder exhibits the most favorable properties.
  • the electrical conductivity of the powder according to Comparative Example 1 is 1050AV ⁇ 1 m ⁇ 1 .
  • This powder exhibits excellent electrical conductivity.
  • the ratio P1 is as low as 2.5%, it easily reacts with oxygen in the atmosphere. This powder tends to cause deterioration of the conductivity over time.
  • the powder according to the present invention can be used for conductive resins, conductive adhesives, conductive pastes for circuits, electronic devices and the like.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Conductive Materials (AREA)
  • Powder Metallurgy (AREA)
  • Non-Insulated Conductors (AREA)
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Abstract

Provided is a powder for conductive fillers, which is composed of a plurality of particles, and wherein: the material for each particle is an alloy that contains from 0.1% by mass to 10% by mass (inclusive) of Bi, with the balance made up of Cu and unavoidable impurities; the alloy contains a first CuBi phase satisfying mathematical formula (1) and a second CuBi phase satisfying mathematical formula (2); each of the particles has a surface layer having a thickness of 100 nm; and the ratio P1 of the first CuBi phase in the surface layer is 5% by mass or more. This powder for conductive fillers has excellent conductivity, and is able to be obtained at low cost. 0.010 ≤ x/y ≤ 1 (1) 0 < x/y ≤ 0.005 (2) (In mathematical formulae (1) and (2), x represents the mass content of Bi and y represents the mass content of Cu.)

Description

導電フィラー用粉末Conductive filler powder
　本発明は、導電性樹脂、導電性接着剤、導電ペースト、電子機器、電子部品等に用いられる導電フィラーに適した粉末に関する。 The present invention relates to a powder suitable for a conductive filler used in a conductive resin, a conductive adhesive, a conductive paste, an electronic device, an electronic component, and the like.
　導電性物質に含有されるフィラーとして、銅を主成分とする合金粉末が知られている。銅の電気抵抗は小さいので、銅を含むフィラーは導電性に優れる。銅粒子の凝集により粒子同士の大きな接触面積が得られるので、この観点からも銅はフィラーの導電性に寄与する。さらに銅は、熱伝導性にも優れる。 An alloy powder containing copper as a main component is known as a filler contained in a conductive substance. Since the electrical resistance of copper is small, the filler containing copper is excellent in conductivity. Since a large contact area between the particles can be obtained by aggregation of the copper particles, copper also contributes to the conductivity of the filler from this viewpoint. Furthermore, copper is excellent in thermal conductivity.
　銅は、酸化しやすい。換言すれば、銅は大気中の酸素と反応しやすい。この反応により酸化被膜が生じる。この酸化被膜は、導電性を阻害する。銅を主成分とする合金からなるフィラーでは、酸化防止処理、酸化被膜除去処理等の表面処理が必要である。 Copper is easy to oxidize. In other words, copper tends to react with oxygen in the atmosphere. This reaction produces an oxide film. This oxide film inhibits conductivity. A filler made of an alloy containing copper as a main component requires a surface treatment such as an antioxidant treatment or an oxide film removal treatment.
　特開２０１５－７４８０６公報には、Ｃｕと１～３０質量％のＡｇとを含む合金からなる導電フィラーが開示されている。このフィラーでは、粒子の表層にＡｇの濃度が高いＡｇＣｕ相が存在している。 JP-A-2015-74806 discloses a conductive filler made of an alloy containing Cu and 1 to 30% by mass of Ag. In this filler, an AgCu phase having a high Ag concentration is present on the surface layer of the particles.
　特開平５－１１４３０５号公報には、Ａｇ－Ｃｕ系合金からなる粉末が開示されている。この粉末は、Ｂｉ、Ｚｎ又はＰｂを含有する。Ｂｉ、Ｚｎ及びＰｂの融点は、低い。 Japanese Patent Laid-Open No. 5-114305 discloses a powder made of an Ag—Cu alloy. This powder contains Bi, Zn or Pb. Bi, Zn and Pb have low melting points.
　特開２０１３－１６３１８５公報には、Ｃｕ－Ｂｉ系合金からなるフィラーが開示されている。このフィラーは、５０～９９質量％のＣｕと、１～５０質量％のＢｉとを含有する。 JP 2013-163185 discloses a filler made of a Cu—Bi alloy. This filler contains 50 to 99% by mass of Cu and 1 to 50% by mass of Bi.
　特開２０１４－２８３８０公報には、Ｃｕ－Ｂｉ系合金からなるフィラーが開示されている。このフィラーは、Ｃｕと、１～５０質量％のＢｉとを含有する。 JP 2014-28380 A discloses a filler made of a Cu-Bi alloy. This filler contains Cu and 1 to 50% by mass of Bi.
特開２０１５－７４８０６公報JP-A-2015-74806 特開平５－１１４３０５号公報Japanese Patent Laid-Open No. 5-114305 特開２０１３－１６３１８５公報JP2013-163185A 特開２０１４－２８３８０公報JP 2014-28380 A
　一般的なＣｕ系粉末では、Ｃｕの表面に、有機溶剤による表面処理が施されている。この表面処理には、手間がかかる。この粉末の製造コストは、高い。導電性と低コストとの両立は、容易ではない。 In general Cu-based powder, the surface of Cu is surface-treated with an organic solvent. This surface treatment takes time and effort. The production cost of this powder is high. It is not easy to achieve both conductivity and low cost.
　本発明の目的は、導電性に優れ、かつ低コストで得られうる導電フィラー用粉末の提供にある。 An object of the present invention is to provide a conductive filler powder that is excellent in conductivity and can be obtained at low cost.
　本発明に係る導電フィラー用粉末は、複数の粒子からなる。それぞれの粒子の材質は、０．１質量％以上１０質量％以下のＢｉを含み、かつ残部がＣｕ及び不可避的不純物である合金である。この合金は、下記数式（１）を満たす第一ＣｕＢｉ相と、下記数式（２）を満たす第二ＣｕＢｉ相とを含む。この粒子は、その厚みが１００ｎｍである表層部を有している。この表層部における第一ＣｕＢｉ相の比率Ｐ１は、５質量％以上である。
　　０．０１０ ≦ ｘ／ｙ ≦ １　　　（１）
　　０ ＜ ｘ／ｙ ≦ ０．００５　　　（２）
この数式（１）及び（２）において、ｘはＢｉの質量含有率を表し、ｙはＣｕの質量含有率を表わす。 The conductive filler powder according to the present invention comprises a plurality of particles. The material of each particle is an alloy containing 0.1 mass% or more and 10 mass% or less of Bi, with the balance being Cu and inevitable impurities. This alloy includes a first CuBi phase satisfying the following formula (1) and a second CuBi phase satisfying the following formula (2). This particle has a surface layer portion having a thickness of 100 nm. The ratio P1 of the first CuBi phase in the surface layer portion is 5% by mass or more.
0.010 ≦ x / y ≦ 1 (1)
0 <x / y ≦ 0.005 (2)
In these mathematical formulas (1) and (2), x represents the mass content of Bi, and y represents the mass content of Cu.
　他の観点によれば、本発明に係る導電フィラー用粉末は、複数の粒子からなる。それぞれの粒子の材質は、０．１質量％以上１０質量％以下のＢｉと、元素Ｘ１とを含み、かつ残部がＣｕ及び不可避的不純物である合金である。この元素Ｘ１は、Ｓｎ、Ｉｎ、Ｚｎ、Ｇａ及びＰｂからなる群より選択された１種又は２種以上である。この合金は、下記数式（１）を満たす第一ＣｕＢｉ相と、下記数式（２）を満たす第二ＣｕＢｉ相とを含む。この粒子は、その厚みが１００ｎｍである表層部を有している。この表層部における第一ＣｕＢｉ相の比率Ｐ１は、５質量％以上である。
　　０．０１０ ≦ ｘ／ｙ ≦ １　　　（１）
　　０ ＜ ｘ／ｙ ≦ ０．００５　　　（２）
この数式（１）及び（２）において、ｘはＢｉの質量含有率を表し、ｙはＣｕの質量含有率を表わす。好ましくは、元素Ｘ１の含有率は、１質量％以上１０質量％以下である。 According to another aspect, the conductive filler powder according to the present invention comprises a plurality of particles. The material of each particle is an alloy containing 0.1 mass% or more and 10 mass% or less of Bi and the element X1, with the balance being Cu and inevitable impurities. This element X1 is one or more selected from the group consisting of Sn, In, Zn, Ga and Pb. This alloy includes a first CuBi phase satisfying the following formula (1) and a second CuBi phase satisfying the following formula (2). This particle has a surface layer portion having a thickness of 100 nm. The ratio P1 of the first CuBi phase in the surface layer portion is 5% by mass or more.
0.010 ≦ x / y ≦ 1 (1)
0 <x / y ≦ 0.005 (2)
In these mathematical formulas (1) and (2), x represents the mass content of Bi, and y represents the mass content of Cu. Preferably, the content rate of the element X1 is 1 mass% or more and 10 mass% or less.
　好ましくは、粉末の累積５０体積％粒子径（Ｄ５０）は、１μｍ以上１０μｍ以下である。 Preferably, the cumulative 50 volume% particle diameter (D 50 ) of the powder is 1 μm or more and 10 μm or less.
　本発明に係る導電フィラー用粉末は、Ｃｕを含有するので、導電性に優れる。この粉末の製造には、コーティング等の表面処理は不要である。従って、この粉末の製造には、手間がかからない。この粉末は、低コストで得られうる。 Since the conductive filler powder according to the present invention contains Cu, it is excellent in conductivity. The production of this powder does not require surface treatment such as coating. Therefore, it takes less time to produce this powder. This powder can be obtained at low cost.
図１は、本発明の一実施形態に係る粉末に含まれる粒子が示された模式的断面図である。FIG. 1 is a schematic cross-sectional view showing particles contained in a powder according to an embodiment of the present invention. 図２は、図１において矢印IIで示された部分の拡大図である。FIG. 2 is an enlarged view of a portion indicated by an arrow II in FIG. 図３は、図１において矢印IIIで示された部分の拡大図である。FIG. 3 is an enlarged view of a portion indicated by an arrow III in FIG.
　以下、適宜図面が参照されつつ、好ましい実施形態に基づいて本発明が詳細に説明される。 Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.
　本発明に係る導電フィラー用粉末は、多数の粒子の集合である。図１に、この粒子２の断面が拡大されて示されている。この粒子２の材質は、合金である。この合金はＣｕ及びＢｉを含んでいる。 The conductive filler powder according to the present invention is a collection of a large number of particles. FIG. 1 shows an enlarged cross section of the particle 2. The material of the particles 2 is an alloy. This alloy contains Cu and Bi.
　好ましくは、この合金は、
　（１）Ｃｕ
　（２）Ｂｉ及び
　（３）不可避的不純物
のみを含む。 Preferably, the alloy is
(1) Cu
(2) Bi and (3) Contains only inevitable impurities.
　図２及び３に示されるように、この合金は、Ｃｕ相４、Ｂｉ相６、第一ＣｕＢｉ相８及び第二ＣｕＢｉ相１０を有している。Ｂｉ相６、第一ＣｕＢｉ相８及び第二ＣｕＢｉ相１０は、Ｃｕ相４中に分散して析出している。 2 and 3, this alloy has a Cu phase 4, a Bi phase 6, a first CuBi phase 8, and a second CuBi phase 10. The Bi phase 6, the first CuBi phase 8, and the second CuBi phase 10 are dispersed and precipitated in the Cu phase 4.
　Ｃｕ相４の主成分は、Ｃｕである。Ｃｕ相４が、Ｃｕのみを含んでもよい。Ｃｕ相４が、Ｃｕと共に、少量の他の元素を含んでもよい。Ｃｕ相４におけるＣｕの比率は９０質量％以上である。Ｃｕは、導電性である。 The main component of the Cu phase 4 is Cu. The Cu phase 4 may contain only Cu. The Cu phase 4 may contain a small amount of other elements together with Cu. The ratio of Cu in the Cu phase 4 is 90% by mass or more. Cu is conductive.
　Ｂｉ相６の主成分は、Ｂｉである。Ｂｉ相６が、Ｂｉのみを含んでもよい。Ｂｉ相６が、Ｂｉと共に、少量の他の元素を含んでもよい。Ｂｉ相６におけるＢｉの比率は９０質量％以上である。Ｂｉの導電性は、低い。 The main component of Bi phase 6 is Bi. Bi phase 6 may contain only Bi. The Bi phase 6 may contain a small amount of other elements together with Bi. The ratio of Bi in the Bi phase 6 is 90% by mass or more. The conductivity of Bi is low.
　第一ＣｕＢｉ相８は、Ｃｕ及びＢｉを含有する。この第一ＣｕＢｉ相８は、ＣｕとＢｉとの化合物を含みうる。第一ＣｕＢｉ相８は、下記数式（１）を満たす。
　　０．０１０ ≦ ｘ／ｙ ≦ １　　　（１）
この数式（１）において、ｘはＢｉの質量含有率を表し、ｙはＣｕの質量含有率を表わす。 The first CuBi phase 8 contains Cu and Bi. The first CuBi phase 8 can include a compound of Cu and Bi. The first CuBi phase 8 satisfies the following mathematical formula (1).
0.010 ≦ x / y ≦ 1 (1)
In this mathematical formula (1), x represents the mass content of Bi, and y represents the mass content of Cu.
　上記数式（１）から明かなとおり、第一ＣｕＢｉ相８におけるＢｉの含有率ｘは、比較的大きい。換言すれば、第一ＣｕＢｉ相８では、Ｂｉが濃化している。従って、この第一ＣｕＢｉ相８の導電性は、小さい。 As is clear from the above formula (1), the Bi content x in the first CuBi phase 8 is relatively large. In other words, Bi is concentrated in the first CuBi phase 8. Therefore, the conductivity of the first CuBi phase 8 is small.
　第二ＣｕＢｉ相１０は、Ｃｕ及びＢｉを含有する。この第二ＣｕＢｉ相１０は、ＣｕとＢｉとの化合物を含みうる。第二ＣｕＢｉ相１０は、下記数式（２）を満たす。
　　０ ＜ ｘ／ｙ ≦ ０．００５　　　（２）
この数式（２）において、ｘはＢｉの質量含有率を表し、ｙはＣｕの質量含有率を表わす。 The second CuBi phase 10 contains Cu and Bi. The second CuBi phase 10 can contain a compound of Cu and Bi. The second CuBi phase 10 satisfies the following mathematical formula (2).
0 <x / y ≦ 0.005 (2)
In this numerical formula (2), x represents the mass content of Bi, and y represents the mass content of Cu.
　上記数式（２）から明かなとおり、第二ＣｕＢｉ相１０におけるＢｉの含有率ｘは、比較的小さい。一方、Ｃｕの含有率は、比較的大きい。換言すれば、第二ＣｕＢｉ相１０では、Ｃｕが濃化している。従って、この第二ＣｕＢｉ相１０は、導電性に優れる。 As is clear from the above formula (2), the Bi content x in the second CuBi phase 10 is relatively small. On the other hand, the Cu content is relatively large. In other words, Cu is concentrated in the second CuBi phase 10. Therefore, this second CuBi phase 10 is excellent in conductivity.
　図２及び３において二点鎖線Ｌで示されているのは、境界線である。境界線Ｌは仮想の線であり、実際には粒子２において境界線Ｌは視認され得ない。この境界線Ｌにより、粒子２は、表層部１２とコア１４とに区画される。表層部１２の厚みＴ（図２参照）は、１００ｎｍである。 In FIGS. 2 and 3, what is indicated by a two-dot chain line L is a boundary line. The boundary line L is a virtual line, and in practice, the boundary line L cannot be visually recognized in the particle 2. The particle 2 is partitioned into the surface layer portion 12 and the core 14 by the boundary line L. The thickness T (see FIG. 2) of the surface layer portion 12 is 100 nm.
　図２及び３から明らかなように、第一ＣｕＢｉ相８は、主に表層部１２に存在している。前述の通り、第一ＣｕＢｉ相８におけるＢｉの含有率ｘは、大きい。この第一ＣｕＢｉ相８が表層部１２に存在するので、コア１４のＣｕ相４におけるＣｕの、大気中の酸素との反応が、抑制されうる。さらに、コア１４の第二ＣｕＢｉ相１０におけるＣｕの、大気中の酸素との反応も、抑制されうる。この第一ＣｕＢｉ相８は、粉末の導電性の経時劣化を抑制しうる。 2 and 3, the first CuBi phase 8 is mainly present in the surface layer portion 12. As described above, the Bi content x in the first CuBi phase 8 is large. Since the first CuBi phase 8 exists in the surface layer portion 12, the reaction of Cu in the Cu phase 4 of the core 14 with oxygen in the atmosphere can be suppressed. Furthermore, the reaction of Cu in the second CuBi phase 10 of the core 14 with oxygen in the atmosphere can also be suppressed. The first CuBi phase 8 can suppress the deterioration of the conductivity of the powder over time.
　第一ＣｕＢｉ相８の融点は、低い。この粉末が例えば導電ペーストに用いられ加熱されたとき、比較的低温（例えば２５０～６００℃）で、第一ＣｕＢｉ相８の微細共晶組織が融解する。融解後の冷却により、微細共晶組織が消滅する。 The melting point of the first CuBi phase 8 is low. When this powder is used in, for example, a conductive paste and heated, the fine eutectic structure of the first CuBi phase 8 melts at a relatively low temperature (for example, 250 to 600 ° C.). The fine eutectic structure disappears by cooling after melting.
　微細共晶組織の消滅時に、Ｂｉが凝集して純Ｂｉ相が形成される。Ｂｉの融点は低い。純Ｂｉ相のＢｉ原子は、拡散により粒子２同士の金属結合を生じさせる。この金属結合により、粒子２間の接触抵抗が低減される。冷却後の生成物は、導電性に優れる。 When the fine eutectic structure disappears, Bi aggregates to form a pure Bi phase. Bi has a low melting point. Bi atoms in the pure Bi phase cause metal bonds between the particles 2 by diffusion. This metal bond reduces the contact resistance between the particles 2. The product after cooling is excellent in conductivity.
　前述の通り、第一ＣｕＢｉ相８は主として表層部１２に存在する。従って、微細共晶組織の消滅によって形成される純Ｂｉ相も、主として表層部１２に存在する。この粒子２では、コア１４の全部又は一部が、Ｂｉによって覆われる。従って、コア１４に存在するＣｕの酸化が抑制される。酸化の抑制により、電気伝導度の経時劣化が抑制される。 As described above, the first CuBi phase 8 is mainly present in the surface layer portion 12. Therefore, the pure Bi phase formed by the disappearance of the fine eutectic structure is also mainly present in the surface layer portion 12. In this particle 2, all or part of the core 14 is covered with Bi. Therefore, the oxidation of Cu existing in the core 14 is suppressed. By suppressing oxidation, deterioration of electrical conductivity over time is suppressed.
　微細共晶組織の消滅時に、Ｃｕが凝集して純Ｃｕ相が形成される。この純Ｃｕ相を有する粒子２同士の接触抵抗は、小さい。冷却後の生成物は、導電性に優れる。 At the disappearance of the fine eutectic structure, Cu aggregates to form a pure Cu phase. The contact resistance between the particles 2 having a pure Cu phase is small. The product after cooling is excellent in conductivity.
　粉末の導電性の観点から、表層部１２における第一ＣｕＢｉ相８の比率Ｐ１は、５質量％以上が好ましく、６質量％以上がより好ましく、７質量％以上が特に好ましい。この比率Ｐ１は、１０質量％以下が好ましい。 From the viewpoint of powder conductivity, the ratio P1 of the first CuBi phase 8 in the surface layer portion 12 is preferably 5% by mass or more, more preferably 6% by mass or more, and particularly preferably 7% by mass or more. The ratio P1 is preferably 10% by mass or less.
　図２及び３から明らかなように、第二ＣｕＢｉ相１０は、主にコア１４に存在している。前述の通り、第二ＣｕＢｉ相１０は、Ｃｕを多く含む。このＣｕは、大気中の酸素と反応しにくい。この粒子２では、電気伝導度の経時劣化が抑制される。 2 and 3, the second CuBi phase 10 is mainly present in the core 14. As described above, the second CuBi phase 10 contains a large amount of Cu. This Cu hardly reacts with oxygen in the atmosphere. In this particle 2, deterioration with time of electric conductivity is suppressed.
　第二ＣｕＢｉ相１０のＢｉは、エレクトロマイグレーションを抑制する。従ってこの粒子２では、電気伝導度の経時劣化が抑制される。 Bi of the second CuBi phase 10 suppresses electromigration. Therefore, in this particle 2, deterioration with time of electric conductivity is suppressed.
　前述の通り、第一ＣｕＢｉ相８は、上記数式（１）を満たす。換言すれば、第一ＣｕＢｉ相８における比（ｘ／ｙ）は、０．０１０以上１以下である。比（ｘ／ｙ）が０．０１０以上である第一ＣｕＢｉ相８は、電気伝導度の経時劣化を抑制する。この観点から、比（ｘ／ｙ）は０．１０以上がより好ましく、０．２０以上が特に好ましい。比（ｘ／ｙ）が１以下である第一ＣｕＢｉ相８は、粉末の導電性を阻害しにくい。この観点から、比（ｘ／ｙ）は０．５０以下がより好ましく、０．３０以下が特に好ましい。 As described above, the first CuBi phase 8 satisfies the above formula (1). In other words, the ratio (x / y) in the first CuBi phase 8 is not less than 0.010 and not more than 1. The first CuBi phase 8 having a ratio (x / y) of 0.010 or more suppresses deterioration of electrical conductivity over time. From this viewpoint, the ratio (x / y) is more preferably 0.10 or more, and particularly preferably 0.20 or more. The first CuBi phase 8 having a ratio (x / y) of 1 or less is unlikely to hinder the conductivity of the powder. In this respect, the ratio (x / y) is more preferably equal to or less than 0.50, and particularly preferably equal to or less than 0.30.
　前述の通り、第二ＣｕＢｉ相１０は、上記数式（２）を満たす。換言すれば、第二ＣｕＢｉ相１０における比（ｘ／ｙ）は、０を超えて０．００５以下である。比（ｘ／ｙ）が０を超える第二ＣｕＢｉ相１０では、エレクトロマイグレーションが抑制されうる。この観点から、比（ｘ／ｙ）は０．０００５以上がより好ましく、０．００１以上が特に好ましい。比（ｘ／ｙ）が０．００５以下である第二ＣｕＢｉ相１０は、導電性に優れる。この観点から、比（ｘ／ｙ）は０．００３以下がより好ましく、０．００２以下が特に好ましい。 As described above, the second CuBi phase 10 satisfies the above mathematical formula (2). In other words, the ratio (x / y) in the second CuBi phase 10 is more than 0 and 0.005 or less. In the second CuBi phase 10 in which the ratio (x / y) exceeds 0, electromigration can be suppressed. In this respect, the ratio (x / y) is more preferably equal to or greater than 0.0005, and particularly preferably equal to or greater than 0.001. The second CuBi phase 10 having a ratio (x / y) of 0.005 or less is excellent in conductivity. In this respect, the ratio (x / y) is more preferably equal to or less than 0.003, and particularly preferably equal to or less than 0.002.
　合金におけるＢｉの量は、０．１質量％以上１０質量％以下が好ましい。この量が０．１質量％以上である合金では、エレクトロマイグレーションが抑制される。この量が０．１質量％以上である合金では、電気伝導度の経時劣化が抑制される。これらの観点から、この量は０．３質量％以上がより好ましく、０．５質量％以上が特に好ましい。この量が１０質量％以下である合金では、Ｂｉによる導電性阻害が少ない。この観点から、この量は７質量％以下がより好ましく、５質量％以下が特に好ましい。 The amount of Bi in the alloy is preferably 0.1% by mass or more and 10% by mass or less. In an alloy having this amount of 0.1% by mass or more, electromigration is suppressed. In an alloy in which this amount is 0.1% by mass or more, deterioration of electric conductivity with time is suppressed. From these viewpoints, this amount is more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more. In an alloy having this amount of 10% by mass or less, there is little conductivity inhibition by Bi. In this respect, the amount is more preferably equal to or less than 7% by weight, and particularly preferably equal to or less than 5% by weight.
　導電性の観点から、合金におけるＣｕの量は９０質量％以上が好ましく、９２質量％以上がより好ましく、９４質量％以上が特に好ましい。本発明において各元素の比率は、ＦＥ－ＳＥＭ像の分析によって決定される。無作為に抽出された２０点において比率が決定され、その平均が算出される。 From the viewpoint of conductivity, the amount of Cu in the alloy is preferably 90% by mass or more, more preferably 92% by mass or more, and particularly preferably 94% by mass or more. In the present invention, the ratio of each element is determined by analysis of the FE-SEM image. Ratios are determined at 20 randomly extracted points and the average is calculated.
　導電性の観点から、粉末の累積５０体積％粒子径（Ｄ５０）は、１５μｍ以下が好ましく、１２ｍ以下がより好ましく、１０μｍ以下が特に好ましい。粉末の凝集が抑制されうるとの観点から、粒子径（Ｄ５０）は１μｍ以上が好ましく、３μｍ以上がより好ましく、４μｍ以上が特に好ましい。粒子径（Ｄ５０）は、粉体の全体積を１００％として累積カーブが求められたとき、その累積カーブが５０％となる点の粒子径である。粒子径（Ｄ５０）は、日機装社のレーザー回折・散乱式粒子径分布測定装置「マイクロトラックＭＴ３０００」により測定される。この装置のセル内に、粉末が純水と共に流し込まれ、粒子２の光散乱情報に基づいて、粒子径（Ｄ５０）が検出される。１０回の測定の平均値が算出される。 From the viewpoint of conductivity, the cumulative 50 volume% particle diameter (D 50 ) of the powder is preferably 15 μm or less, more preferably 12 m or less, and particularly preferably 10 μm or less. From the viewpoint that aggregation of the powder can be suppressed, the particle diameter (D 50 ) is preferably 1 μm or more, more preferably 3 μm or more, and particularly preferably 4 μm or more. The particle diameter (D 50 ) is the particle diameter at which the cumulative curve becomes 50% when the cumulative curve is obtained with the total volume of the powder as 100%. The particle diameter (D 50 ) is measured by a laser diffraction / scattering particle size distribution measuring apparatus “Microtrack MT3000” manufactured by Nikkiso Co., Ltd. Powder is poured into the cell of this apparatus together with pure water, and the particle diameter (D 50 ) is detected based on the light scattering information of the particles 2. An average value of 10 measurements is calculated.
　Ｃｕ－Ｂｉ合金の融点は、Ｃｕの融点よりも低い。溶融したＣｕ－Ｂｉ合金の粘度は、溶融したＣｕの粘度よりも低い。この合金から、アトマイズにより、容易に微細な粉末が得られうる。その理由は、
　（１）高温な溶湯が準備される必要がない
　（２）アトマイズの噴射圧が高圧である必要がない及び
　（３）微細噴射ノズルが採用される必要がないことにある。 The melting point of the Cu—Bi alloy is lower than the melting point of Cu. The viscosity of the molten Cu—Bi alloy is lower than the viscosity of the molten Cu. From this alloy, fine powder can be easily obtained by atomization. The reason is,
(1) It is not necessary to prepare a high-temperature molten metal (2) The atomizing injection pressure does not need to be high, and (3) It is not necessary to employ a fine injection nozzle.
　合金が、元素Ｘ１をさらに含んでもよい。元素Ｘ１は、Ｓｎ、Ｉｎ、Ｚｎ、Ｇａ及びＰｂからなる群より選択された１種又は２種以上である。元素Ｘ１を含む場合、好ましくは、この合金は、
　（１）Ｃｕ
　（２）Ｂｉ
　（３）元素Ｘ１及び
　（４）不可避的不純物
のみを含む。 The alloy may further include an element X1. The element X1 is one or more selected from the group consisting of Sn, In, Zn, Ga, and Pb. When containing the element X1, preferably the alloy is
(1) Cu
(2) Bi
(3) Element X1 and (4) Contains only inevitable impurities.
　元素Ｘ１を含む合金の融点は、低い。溶融した合金の粘度は、低い。この合金から、アトマイズにより、容易に微細な粉末が得られうる。その理由は、
　（１）高温な溶湯が準備される必要がない
　（２）アトマイズの噴射圧が高圧である必要がない及び
　（３）微細噴射ノズルが採用される必要がないことにある。 The melting point of the alloy containing the element X1 is low. The viscosity of the molten alloy is low. From this alloy, fine powder can be easily obtained by atomization. The reason is,
(1) It is not necessary to prepare a high-temperature molten metal (2) The atomizing injection pressure does not need to be high, and (3) It is not necessary to employ a fine injection nozzle.
　合金における元素Ｘ１の含有率は、１質量％以上が好ましく、２質量％以上がより好ましく、３質量％以上が特に好ましい。導電性の観点から、含有率は１０質量％以下が好ましい。 The content of the element X1 in the alloy is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 3% by mass or more. From the viewpoint of conductivity, the content is preferably 10% by mass or less.
　合金が元素Ｘ１を含む場合も、Ｂｉの含有率は０．１質量％以上が好ましく、０．３質量％以上がより好ましく、０．５質量％以上が特に好ましい。この含有率は、１０質量％以下が好ましく、７質量％以下がより好ましく、５質量％以下が特に好ましい。 When the alloy contains the element X1, the Bi content is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more. This content is preferably 10% by mass or less, more preferably 7% by mass or less, and particularly preferably 5% by mass or less.
　粉末の電気伝導度は、５００ＡＶ－１ｍ－１以上が好ましく、７００ＡＶ－１ｍ－１以上がより好ましく、１０００ＡＶ－１ｍ－１以上が特に好ましい。電気伝導度が高い粉末では、電気抵抗値が小さい。粉末の電気抵抗には、接触している粒子２の間に発生する接触抵抗と、粒子２の内部に発生するバルク抵抗とがある。本発明に係る粉末では、小さな接触抵抗によって優れた導電性が達成されている。 Electrical conductivity of the powder is preferably 500AV -1 m -1 or more, more preferably 700AV -1 m -1 or more, 1000AV -1 m -1 or more are particularly preferred. The powder having high electrical conductivity has a small electrical resistance value. The electric resistance of the powder includes a contact resistance generated between the particles 2 in contact with each other and a bulk resistance generated inside the particles 2. In the powder according to the present invention, excellent conductivity is achieved by a small contact resistance.
　本発明に係る粉末は、アトマイズによって得られうる。粉末の特性は、材質のみならず、アトマイズの冷却速度にも依存する。ガスアトマイズ法、ディスクアトマイズ法、水アトマイズ法等が、採用されうる。粒子径が小さな粉末が容易に得られるとの観点から、ガスアトマイズ法及びディスクアトマイズ法が好ましい。この粉末の製造では、コーティング工程は不要である。この粉末の製造コストは、低い。 The powder according to the present invention can be obtained by atomization. The characteristics of the powder depend not only on the material but also on the atomization cooling rate. A gas atomizing method, a disk atomizing method, a water atomizing method, or the like can be employed. From the viewpoint of easily obtaining a powder having a small particle size, the gas atomizing method and the disk atomizing method are preferable. In the production of this powder, no coating process is required. The production cost of this powder is low.
　ガスアトマイズ法では、底部に細孔を有する石英坩堝の中に、原料が投入される。この原料が、アルゴンガス雰囲気中で、高周波誘導炉によって加熱され、溶融する。アルゴンガス雰囲気において、細孔から流出する原料に、アルゴンガスが噴射される。原料は急冷されて凝固し、粉末が得られる。噴射圧の調整により、凝固速度がコントロールされうる。噴射圧が大きいほど、凝固速度は大きい。凝固速度のコントロールにより、所望の粒度分布を有する粉末が得られうる。凝固速度が速いほど、粒度分布の幅は小さい。 In the gas atomization method, raw materials are put into a quartz crucible having pores at the bottom. This raw material is heated and melted by a high frequency induction furnace in an argon gas atmosphere. In an argon gas atmosphere, argon gas is injected onto the raw material flowing out from the pores. The raw material is rapidly cooled and solidified to obtain a powder. The coagulation rate can be controlled by adjusting the injection pressure. The greater the injection pressure, the greater the solidification rate. By controlling the solidification rate, a powder having a desired particle size distribution can be obtained. The faster the solidification rate, the smaller the width of the particle size distribution.
　ディスクアトマイズ法では、底部に細孔を有する石英坩堝の中に、原料が投入される。この原料が、アルゴンガス雰囲気中で、高周波誘導炉によって加熱され、溶融する。アルゴンガス雰囲気において、細孔から流出する原料が、高速で回転するディスクの上に落とされる。回転速度は、４００００ｒｐｍから６００００ｒｐｍである。ディスクによって原料は急冷され、凝固して、粉末が得られる。この粉末にミリングが施されてもよい。 In the disc atomization method, raw materials are put into a quartz crucible having pores at the bottom. This raw material is heated and melted by a high frequency induction furnace in an argon gas atmosphere. In an argon gas atmosphere, the raw material flowing out from the pores is dropped onto a disk that rotates at high speed. The rotation speed is 40000 rpm to 60000 rpm. The raw material is rapidly cooled by the disk and solidified to obtain a powder. This powder may be milled.
　以下、実施例によって本発明の効果が明らかにされるが、この実施例の記載に基づいて本発明が限定的に解釈されるべきではない。 Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be interpreted in a limited manner based on the description of the examples.
　表１及び２に示される実施例１～２０及び比較例１～２０の粉末を得た。各粉末の成分の、表に記載されていない残部は、不可避的不純物である。 The powders of Examples 1 to 20 and Comparative Examples 1 to 20 shown in Tables 1 and 2 were obtained. The remainder of each powder component not listed in the table is an unavoidable impurity.
　各粉末の電気伝導度を測定した。まず、篩を用いて径が４５μｍを超える粒子を粉末から除去した。この粉末を、直径が２５ｍｍであり高さが１０ｍｍである円柱状のサンプルホルダー（東陽テクニカ社の粉体インピーダンス測定用四端子サンプルホルダー）に充填した。この粉末に、上下から４Ｎｍの荷重をかけた。この粉末の上側に電流のプラス端子及び電圧のプラス端子を取り付けた。この粉末の下側に電流のマイナス端子及び電圧のマイナス端子を取り付けた。いわゆる四端子法により、電流を流して電圧を測定した。この結果が、下記の表１及び２に示されている。 The electrical conductivity of each powder was measured. First, particles having a diameter exceeding 45 μm were removed from the powder using a sieve. This powder was filled into a cylindrical sample holder (four-terminal sample holder for powder impedance measurement by Toyo Technica Co., Ltd.) having a diameter of 25 mm and a height of 10 mm. A load of 4 Nm was applied to the powder from above and below. A positive terminal for current and a positive terminal for voltage were attached to the upper side of the powder. A negative terminal for current and a negative terminal for voltage were attached to the lower side of the powder. The voltage was measured by applying a current by the so-called four-terminal method. The results are shown in Tables 1 and 2 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１では、各粉末が、Ａ～Ｄの格付けで評価されている。この評価の基準は、以下の通りである。
　格付けＡ
　　　粒子径（Ｄ５０）：１μｍ以上１０μｍ以下
　　　電気伝導度：１０００ＡＶ－１ｍ－１以上
　格付けＢ
　　　粒子径（Ｄ５０）：１０μｍ以上
　　　電気伝導度：１０００ＡＶ－１ｍ－１以上
　格付けＣ
　　　粒子径（Ｄ５０）：１μｍ以上１０μｍ以下
　　　電気伝導度：５００ＡＶ－１ｍ－１以上１０００ＡＶ－１ｍ－１未満
　格付けＤ
　　　粒子径（Ｄ５０）：１μｍ以上１０μｍ以下
　　　電気伝導度：５００ＡＶ－１ｍ－１未満 In Table 1, each powder is rated with an AD rating. The criteria for this evaluation are as follows.
Rating A
Particle diameter (D 50 ): 1 μm or more and 10 μm or less Electrical conductivity: 1000 AV −1 m −1 or more Rating B
Particle size (D 50 ): 10 μm or more Electrical conductivity: 1000 AV −1 m −1 or more Rating C
Particle diameter (D 50): 1 [mu] m or more 10μm or less electrical conductivity: 500AV -1 m -1 or more 1000AV -1 m less than -1 rating D
Particle diameter (D 50 ): 1 μm or more and 10 μm or less Electric conductivity: less than 500 AV −1 m −1
　表２に示された各比較例の粉末の格付けは、Ｅである。この粉末は、
　（１）組成が本発明の範囲を外れる
　（２）数式（１）を満たさない
　（３）数式（２）を満たさない及び
　（４）比率Ｐ１が本発明の範囲を外れる
のうちのいずれかに該当する。 The rating of each comparative example shown in Table 2 is E. This powder
(1) The composition is out of the scope of the present invention (2) The formula (1) is not satisfied (3) The formula (2) is not satisfied and (4) The ratio P1 is out of the scope of the present invention Applicable.
　例えば、実施例７に係る粉末は、組織が９９Ｃｕ－１Ｂｉである。第一ＣｕＢｉ相における比（ｘ／ｙ）は０．２２であり、数式（１）を満たしている。第二ＣｕＢｉ相におけるｘ／ｙは０．００２０であり、数式（２）を満たしている。さらにこの粉末では、表層部における第一ＣｕＢｉ相の比率Ｐ１は、７．４％である。粒子径（Ｄ５０）は８．７μｍであり、電機伝導度は１３８０ＡＶ－１ｍ－１である。この粉末は、最も好ましい特性を示している。 For example, the powder according to Example 7 has a structure of 99Cu-1Bi. The ratio (x / y) in the first CuBi phase is 0.22, which satisfies Expression (1). X / y in the second CuBi phase is 0.0020, which satisfies Expression (2). Furthermore, in this powder, the ratio P1 of the first CuBi phase in the surface layer portion is 7.4%. The particle diameter (D 50 ) is 8.7 μm, and the electric conductivity is 1380AV −1 m −1 . This powder exhibits the most favorable properties.
　例えば、比較例１に係る粉末の電気伝導度は、１０５０ＡＶ-1ｍ-1である。この粉末は、優れた導電性を示す。しかし、比率Ｐ１は２．５％と低いので、大気中の酸素と反応しやすい。この粉末では、導電性の経時劣化が生じやすい。 For example, the electrical conductivity of the powder according to Comparative Example 1 is 1050AV −1 m −1 . This powder exhibits excellent electrical conductivity. However, since the ratio P1 is as low as 2.5%, it easily reacts with oxygen in the atmosphere. This powder tends to cause deterioration of the conductivity over time.
　以上の評価結果から、本発明の優位性は明かである。 From the above evaluation results, the superiority of the present invention is clear.
　本発明に係る粉末は、導電性樹脂、導電性接着剤、回路用導電ペースト、電子機器等に用いられ得る。 The powder according to the present invention can be used for conductive resins, conductive adhesives, conductive pastes for circuits, electronic devices and the like.

Claims (4)

  1. 　複数の粒子からなり、
    　それぞれの粒子の材質が、０．１質量％以上１０質量％以下のＢｉを含み、かつ残部がＣｕ及び不可避的不純物である合金であり、
    　上記合金が、下記数式（１）を満たす第一ＣｕＢｉ相と、下記数式（２）を満たす第二ＣｕＢｉ相とを含んでおり、
    　上記粒子が、その厚みが１００ｎｍである表層部を有しており、
    　上記表層部における第一ＣｕＢｉ相の比率Ｐ１が、５質量％以上である導電フィラー用粉末。
    　　０．０１０ ≦ ｘ／ｙ ≦ １　　　（１）
    　　０ ＜ ｘ／ｙ ≦ ０．００５　　　（２）
    （上記数式（１）及び（２）において、ｘはＢｉの質量含有率を表し、ｙはＣｕの質量含有率を表わす。）     Consisting of multiple particles,
    The material of each particle is an alloy containing 0.1 mass% or more and 10 mass% or less of Bi, and the balance being Cu and inevitable impurities,
    The alloy includes a first CuBi phase that satisfies the following formula (1) and a second CuBi phase that satisfies the following formula (2):
    The particles have a surface layer part having a thickness of 100 nm,
    The conductive filler powder wherein the ratio P1 of the first CuBi phase in the surface layer portion is 5% by mass or more.
    0.010 ≦ x / y ≦ 1 (1)
    0 <x / y ≦ 0.005 (2)
    (In the above formulas (1) and (2), x represents the mass content of Bi, and y represents the mass content of Cu.)
  2. 　複数の粒子からなり、
    　それぞれの粒子の材質が、０．１質量％以上１０質量％以下のＢｉと、元素Ｘ１とを含み、かつ残部がＣｕ及び不可避的不純物である合金であり、
    　上記元素Ｘ１が、Ｓｎ、Ｉｎ、Ｚｎ、Ｇａ及びＰｂからなる群より選択された１種又は２種以上であり、
    　上記合金が、下記数式（１）を満たす第一ＣｕＢｉ相と、下記数式（２）を満たす第二ＣｕＢｉ相とを含んでおり、
    　上記粒子が、その厚みが１００ｎｍである表層部を有しており、
    　上記表層部における第一ＣｕＢｉ相の比率Ｐ１が、５質量％以上である導電フィラー用粉末。
    　　０．０１０ ≦ ｘ／ｙ ≦ １　　　（１）
    　　０ ＜ ｘ／ｙ ≦ ０．００５　　　（２）
    （上記数式（１）及び（２）において、ｘはＢｉの質量含有率を表し、ｙはＣｕの質量含有率を表わす。）     Consisting of multiple particles,
    The material of each particle is an alloy containing 0.1% by mass or more and 10% by mass or less of Bi and the element X1, and the balance being Cu and inevitable impurities,
    The element X1 is one or more selected from the group consisting of Sn, In, Zn, Ga and Pb,
    The alloy includes a first CuBi phase that satisfies the following formula (1) and a second CuBi phase that satisfies the following formula (2):
    The particles have a surface layer part having a thickness of 100 nm,
    The conductive filler powder wherein the ratio P1 of the first CuBi phase in the surface layer portion is 5% by mass or more.
    0.010 ≦ x / y ≦ 1 (1)
    0 <x / y ≦ 0.005 (2)
    (In the above formulas (1) and (2), x represents the mass content of Bi, and y represents the mass content of Cu.)
  3. 　上記元素Ｘ１の含有率が１質量％以上１０質量％以下である請求項２に記載の粉末。 The powder according to claim 2, wherein the content of the element X1 is 1% by mass or more and 10% by mass or less.
  4. 　その累積５０体積％粒子径（Ｄ５０）が１μｍ以上１０μｍ以下である請求項１から３のいずれかに記載の粉末。 Powder according to any one of claims 1-3 cumulative 50% particle diameter (D 50) is 1μm or more 10μm or less.
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WO2002070762A1 (en) * 2001-03-06 2002-09-12 Kiyohito Ishida Member having separation structure and method for manufacture thereof
JP2010196105A (en) * 2009-02-24 2010-09-09 Mitsui Mining & Smelting Co Ltd Copper powder for electroconductive paste, and electroconductive paste
JP2012126981A (en) * 2010-12-17 2012-07-05 Mitsui Mining & Smelting Co Ltd Cu ALLOY FOR WIRING AND CONNECTION STRUCTURE USING THE SAME
JP2013163185A (en) * 2012-02-09 2013-08-22 Asahi Kasei E-Materials Corp Filler metal, solder paste, and connecting structure
JP5386373B2 (en) * 2008-01-23 2014-01-15 大豊工業株式会社 Method for producing sintered copper alloy sliding material and sintered copper alloy sliding material
JP2014028380A (en) * 2012-07-31 2014-02-13 Koki:Kk Metal filler, solder paste, and connection structure
JP2015196877A (en) * 2014-04-01 2015-11-09 山陽特殊製鋼株式会社 POWDER FOR AgCuBi-BASED CONDUCTIVE FILLER

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002070762A1 (en) * 2001-03-06 2002-09-12 Kiyohito Ishida Member having separation structure and method for manufacture thereof
JP5386373B2 (en) * 2008-01-23 2014-01-15 大豊工業株式会社 Method for producing sintered copper alloy sliding material and sintered copper alloy sliding material
JP2010196105A (en) * 2009-02-24 2010-09-09 Mitsui Mining & Smelting Co Ltd Copper powder for electroconductive paste, and electroconductive paste
JP2012126981A (en) * 2010-12-17 2012-07-05 Mitsui Mining & Smelting Co Ltd Cu ALLOY FOR WIRING AND CONNECTION STRUCTURE USING THE SAME
JP2013163185A (en) * 2012-02-09 2013-08-22 Asahi Kasei E-Materials Corp Filler metal, solder paste, and connecting structure
JP2014028380A (en) * 2012-07-31 2014-02-13 Koki:Kk Metal filler, solder paste, and connection structure
JP2015196877A (en) * 2014-04-01 2015-11-09 山陽特殊製鋼株式会社 POWDER FOR AgCuBi-BASED CONDUCTIVE FILLER

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