JP6722495B2 - Silver-coated copper powder and method for producing the same - Google Patents

Silver-coated copper powder and method for producing the same Download PDF

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JP6722495B2
JP6722495B2 JP2016079577A JP2016079577A JP6722495B2 JP 6722495 B2 JP6722495 B2 JP 6722495B2 JP 2016079577 A JP2016079577 A JP 2016079577A JP 2016079577 A JP2016079577 A JP 2016079577A JP 6722495 B2 JP6722495 B2 JP 6722495B2
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silver
copper powder
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JP2017190483A (en
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井上　健一
健一 井上
江原　厚志
厚志 江原
吉田　昌弘
昌弘 吉田
恭三 増田
恭三 増田
山田　雄大
雄大 山田
孝造 尾木
孝造 尾木
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Dowa Electronics Materials Co Ltd
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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
    • 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
    • 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
    • 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
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
    • 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

Description

本発明は、銀被覆銅粉およびその製造方法に関し、特に、導電性ペーストなどに使用する銀被覆銅粉およびその製造方法に関する。 The present invention relates to a silver-coated copper powder and a method for producing the same, and more particularly to a silver-coated copper powder used for a conductive paste and a method for producing the same.

従来、印刷法などにより電子部品の電極や配線を形成するために、銀粉や銅粉などの導電性の金属粉末に溶剤、樹脂、分散剤などを配合して作製した導電性ペーストが使用されている。 Conventionally, a conductive paste prepared by blending a solvent, a resin, a dispersant and the like with a conductive metal powder such as silver powder or copper powder has been used to form electrodes and wiring of electronic parts by a printing method or the like. There is.

しかし、銀粉は、体積抵抗率が極めて小さく、良好な導電性物質であるが、貴金属の粉末であるため、コストが高くなる。一方、銅粉は、体積抵抗率が低く、良好な導電性物質であり、安価であるが、酸化され易いため、銀粉に比べて保存安定性（信頼性）に劣っている。 However, although silver powder has a very small volume resistivity and is a good conductive substance, it is a powder of a noble metal, so that the cost is high. On the other hand, copper powder has a low volume resistivity, is a good conductive substance, and is inexpensive, but since it is easily oxidized, it is inferior in storage stability (reliability) to silver powder.

これらの問題を解消するために、導電性ペーストに使用する金属粉末として、銅粉の表面を銀で被覆した銀被覆銅粉が提案されている（例えば、特許文献１〜２参照）。 In order to solve these problems, silver-coated copper powder in which the surface of copper powder is coated with silver has been proposed as a metal powder used in a conductive paste (see, for example, Patent Documents 1 and 2).

特開２０１０−１７４３１１号公報（段落番号０００３）JP, 2010-174311, A (paragraph number 0003) 特開２０１０−０７７４９５号公報（段落番号０００６）JP, 2010-077495, A (paragraph number 0006)

しかし、特許文献１〜２の銀被覆銅粉では、導電性ペーストに使用して導電膜を作製したときに、導電膜の体積抵抗率が高くなったり、保存安定性（信頼性）が不十分な場合があった。 However, with the silver-coated copper powders of Patent Documents 1 and 2, when a conductive film is produced by using it in a conductive paste, the conductive film has a high volume resistivity and insufficient storage stability (reliability). There was a case.

したがって、本発明は、このような従来の問題点に鑑み、体積抵抗率が低く且つ保存安定性（信頼性）に優れた導電膜の製造に適した導電性ペーストを製造することができる、銀被覆銅粉およびその製造方法を提供することを目的とする。 Therefore, in view of such conventional problems, the present invention can produce a conductive paste suitable for producing a conductive film having a low volume resistivity and excellent storage stability (reliability). An object is to provide a coated copper powder and a method for producing the same.

本発明者らは、上記課題を解決するために鋭意研究した結果、銅を加熱して溶解した溶湯を落下させながら高圧水を吹き付けて急冷凝固して得られた銅粉のスラリーを非酸化性ガスの存在下で保持した後、固液分離して得られた銅粉を銀含有層で被覆することにより、体積抵抗率が低く且つ保存安定性（信頼性）に優れた導電膜の製造に適した導電性ペーストを製造することができることを見出し、本発明を完成するに至った。 As a result of intensive research to solve the above problems, the inventors of the present invention non-oxidize the copper powder slurry obtained by rapidly cooling and solidifying by spraying high-pressure water while heating molten copper and dropping the molten metal. By holding the copper powder obtained by solid-liquid separation after holding in the presence of gas with a silver-containing layer, it is possible to manufacture a conductive film with low volume resistivity and excellent storage stability (reliability). The inventors have found that a suitable conductive paste can be produced, and completed the present invention.

すなわち、本発明による銀被覆銅粉は、銅を加熱して溶解した溶湯を落下させながら高圧水を吹き付けて急冷凝固して得られた銅粉のスラリーを非酸化性ガスの存在下で保持した後、固液分離して得られた銅粉を銀含有層で被覆することを特徴とする。 That is, the silver-coated copper powder according to the present invention, the slurry of the copper powder obtained by rapidly solidifying by spraying high-pressure water while heating molten copper and dropping the molten metal was held in the presence of a non-oxidizing gas. Thereafter, the copper powder obtained by solid-liquid separation is coated with a silver-containing layer.

この銀被覆銅粉の製造方法において、スラリー中とスラリーを収容する容器内との少なくとも一方に非酸化性ガスを吹き込みながら保持することによって、スラリーを非酸化性ガスの存在下で保持するのが好ましい。また、銅粉のレーザー回折式粒度分布装置により測定した体積基準の累積５０％粒子径（Ｄ５０径）が０．１〜１５μｍであるのが好ましい。また、高圧水がアルカリ水溶液であるのが好ましく、溶湯にリンを添加するのが好ましい。 In this method for producing a silver-coated copper powder, by holding the non-oxidizing gas while blowing the non-oxidizing gas into at least one of the slurry and the container containing the slurry, it is possible to hold the slurry in the presence of the non-oxidizing gas. preferable. In addition, the volume-based cumulative 50% particle diameter (D 50 diameter) of the copper powder measured by a laser diffraction particle size distribution device is preferably 0.1 to 15 μm. The high-pressure water is preferably an alkaline aqueous solution, and phosphorus is preferably added to the molten metal.

また、本発明による銀被覆銅粉は、銅粉の表面が銀含有層で被覆された銀被覆銅粉であって、Ｃｕの（２００）面における結晶子径Ｄ（２００）に対するＣｕの（１１１）面における結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２００）が１．８以上であり且つＣｕの（２２０）面における結晶子径Ｄ（２２０）に対するＣｕの（２００）面における結晶子径Ｄ（２００）の比Ｄ（２００）／Ｄ（２２０）が１．０９５以下であることを特徴とする。 Further, the silver-coated copper powder according to the present invention is a silver-coated copper powder in which the surface of the copper powder is coated with a silver-containing layer, and the Cu (111 ) with respect to the crystallite diameter D (200) on the (200) plane of Cu. ) Plane has a ratio D (111) /D (200) of crystallite diameters D (111) of 1.8 or more, and Cu (200) planes with respect to crystallite diameters D (220) of Cu (220 ) planes. The ratio D (200) /D (220) of the crystallite diameter D (200 ) is 1.095 or less.

この銀被覆銅粉において、銀被覆銅粉のＣｕの（２２０）面における結晶子径Ｄ（２２０）に対するＣｕの（１１１）面における結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２２０）が１．９０以上であるのが好ましい。また、銀被覆銅粉のレーザー回折式粒度分布装置により測定した体積基準の累積５０％粒子径（Ｄ５０径）が０．１〜１５μｍであるのが好ましい。また、銀被覆銅粉中のリン含有量が１０〜１０００ｐｐｍであるのが好ましい。 In this silver-coated copper powder, the ratio D (111) /D ( of the crystallite diameter D (111) on the (111) plane of Cu to the crystallite diameter D (220) on the Cu (220) plane of the silver-coated copper powder. 220) is preferably 1.90 or more. Further, it is preferable that the volume-based cumulative 50% particle diameter (D 50 diameter) of the silver-coated copper powder measured by a laser diffraction type particle size distribution device is 0.1 to 15 μm. Further, the phosphorus content in the silver-coated copper powder is preferably 10 to 1000 ppm.

さらに、本発明による導電性ペーストは、導電性粉末として上記の銀被覆銅粉を含むことを特徴とする。 Further, the conductive paste according to the present invention is characterized in that it contains the silver-coated copper powder as a conductive powder.

なお、本明細書中において、「銀被覆銅粉のＣｕの（ｈｋｌ）面における結晶子径Ｄ（ｈｋｌ）」とは、銀被覆銅粉のＸ線回折パターンのＣｕの（ｈｋｌ）ピークの半価幅からシェラーの式を用いて算出した結晶子径をいう。 In the present specification, "crystallite diameter D (hkl) on the Cu (hkl) plane of silver-coated copper powder" means half of the Cu (hkl) peak of the X-ray diffraction pattern of the silver-coated copper powder. The crystallite diameter calculated from the valence band using the Scherrer's formula.

本発明によれば、体積抵抗率が低く且つ保存安定性（信頼性）に優れた導電膜の製造に適した導電性ペーストを製造することができる、銀被覆銅粉およびその製造方法を提供することができる。 According to the present invention, there is provided a silver-coated copper powder capable of producing a conductive paste suitable for producing a conductive film having a low volume resistivity and excellent storage stability (reliability), and a method for producing the same. be able to.

実施例および比較例の銀被覆銅粉のＣｕの（２００）面における結晶子径Ｄ（２００）に対するＣｕの（１１１）面における結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２００）と、その銀被覆銅粉を使用して作製した導電膜を１５０℃で６週間保存した後の体積抵抗率の変化率（％）との関係を示す図である。The ratio D (111) /D (200 ) of the crystallite diameter D (111) on the (111) plane of Cu to the crystallite diameter D (200) on the Cu (200) plane of the silver-coated copper powders of Examples and Comparative Examples. 2) and a change rate (%) of volume resistivity after a conductive film produced using the silver-coated copper powder was stored at 150° C. for 6 weeks. 実施例および比較例の銀被覆銅粉のＣｕの（２２０）面における結晶子径Ｄ（２２０）に対するＣｕの（２００）面における結晶子径Ｄ（２００）の比Ｄ（２００）／Ｄ（２２０）と、その銀被覆銅粉を使用して作製した導電膜を１５０℃で６週間保存した後の体積抵抗率の変化率（％）との関係を示す図である。The ratio D (200) /D (220 ) of the crystallite diameter D (200) of the Cu (200) plane to the crystallite diameter D (220) of the Cu (220) plane of the silver-coated copper powders of Examples and Comparative Examples. 2) and a change rate (%) of volume resistivity after a conductive film produced using the silver-coated copper powder was stored at 150° C. for 6 weeks. 実施例および比較例の銀被覆銅粉の銀被覆層の厚さと、その銀被覆銅粉を使用して作製した導電膜を１５０℃で６週間保存した後の体積抵抗率の変化率（％）との関係を示す図である。The thickness of the silver coating layer of the silver-coated copper powders of Examples and Comparative Examples, and the change rate (%) of the volume resistivity after the conductive film produced using the silver-coated copper powder was stored at 150° C. for 6 weeks. It is a figure which shows the relationship with.

本発明による銀被覆銅粉の製造方法の実施の形態では、銅を加熱して溶解した溶湯を落下させながら高圧水を吹き付けて急冷凝固して得られた銅粉のスラリーを非酸化性ガスの存在下で保持した後、固液分離して得られた銅粉を銀含有層（銀または銀化合物からなる層）で被覆する。なお、固液分離して得られた銅粉は、必要に応じて、乾燥したり、解砕したり、篩別してもよく、水洗してもよい。 In the embodiment of the method for producing a silver-coated copper powder according to the present invention, a slurry of copper powder obtained by rapidly cooling and solidifying by spraying high-pressure water while dropping a molten metal obtained by heating and melting copper is converted into a non-oxidizing gas. After holding in the presence, the copper powder obtained by solid-liquid separation is coated with a silver-containing layer (layer consisting of silver or a silver compound). The copper powder obtained by solid-liquid separation may be dried, crushed, sieved, or washed with water, if necessary.

銅粉は、銅を溶解温度以上の温度（１１００〜１６００℃）に加熱して溶解した溶湯をタンディッシュ下部から落下させながら高圧水を吹き付けて急冷凝固させることにより微粉末とする、所謂水アトマイズ法により製造する。水アトマイズ法により銅粉を製造すると、粒子径が小さい銅粉を得ることができるので、そのような銅粉を銀含有層で被覆した銀被覆銅粉を導電性ペーストに使用した際に粒子間の接触点の増加による導電性の向上を図ることができる。また、高圧水として、ｐＨを高くして銅の腐食を防止するために、アルカリ水を使用するのが好ましく、ｐＨ８〜１２のアルカリ水を５〜５０℃の温度で使用するのがさらに好ましい。このアルカリ水として、純水に水酸化ナトリウムなどのアルカリを溶解したアルカリ水溶液を使用することができる。このように（好ましくはアルカリ水からなる）高圧水を吹き付けて急冷凝固して得られた銅粉のスラリーを非酸化性ガスの存在下で保持した後、固液分離して得られた銅粉を使用することにより、体積抵抗率が低く且つ保存安定性（信頼性）に優れた導電膜の製造に適した導電性ペーストを製造することができる、銀被覆銅粉を製造することができる。また、高圧水は、水圧３０〜１５０ＭＰａで吹き付けられるのが好ましい。 The copper powder is so-called water atomized, which is made into fine powder by spraying high-pressure water while rapidly cooling and solidifying molten metal obtained by heating copper to a temperature above the melting temperature (1100 to 1600° C.) while dropping it from the lower part of the tundish. It is manufactured by the method. When the copper powder is produced by the water atomizing method, it is possible to obtain a copper powder having a small particle size, and therefore, when the silver-coated copper powder coated with such a silver powder in the silver-containing layer is used as the conductive paste, The conductivity can be improved by increasing the number of contact points. Further, as the high-pressure water, it is preferable to use alkaline water in order to increase the pH and prevent corrosion of copper, and it is more preferable to use alkaline water having a pH of 8 to 12 at a temperature of 5 to 50°C. As this alkaline water, an alkaline aqueous solution obtained by dissolving an alkali such as sodium hydroxide in pure water can be used. Copper powder obtained by solid-liquid separation after holding slurry of copper powder obtained by spraying high-pressure water (preferably consisting of alkaline water) and rapid solidification in the presence of non-oxidizing gas By using, it is possible to produce a silver-coated copper powder which can produce a conductive paste suitable for producing a conductive film having a low volume resistivity and excellent storage stability (reliability). Further, the high pressure water is preferably sprayed at a water pressure of 30 to 150 MPa.

非酸化性ガスとして、窒素ガスやアルゴンガスなどの不活性ガス、水素や一酸化炭素などの還元性ガスを使用することができる。これらのガスは、単独で使用してもよいし、所定の割合で混合した混合ガスとして使用してもよい。この非酸化性ガスは、スラリー中に直接吹き込むのが好ましいが、スラリー中に直接吹き込まないでスラリーを収容する（タンクや配管などの）容器内（のスラリー上方の空間）に吹き込んでもよい。このように吹き込む非酸化性ガスの流量は、スラリー中の酸素濃度を十分に低減することができる流量にすればよく、スラリーを収容する（タンクや配管などの）容器内（のスラリー上方の空間）に吹き込む場合には、その（タンクや配管などの）容器内の雰囲気中の酸素濃度を好ましくは１質量％未満（さらに好ましくは０．１質量％未満）にすることができる流量にすればよい。このようにスラリー中の酸素含有量を低減すると、銅粉の酸化（ＣｕＯやＣｕ２Ｏの生成）を抑制することができる。このように銅粉の酸化を抑制すると、Ｃｕの結晶構造が歪められるのを抑制することができると考えられ、このようにして得られた銅粉を銀被覆層で被覆して銀被覆銅粉を製造すると、銀被覆銅粉のＣｕの所定の結晶面における結晶子径を所望の結晶子径にすることができる。このような銅粉の酸化を抑制するために、非酸化性ガスの流量は、１０〜１０００Ｌ／分であるのが好ましく、その吹き込みを保持する時間（スラリー中やスラリーを収容する（タンクや配管などの）容器内に非酸化性ガスを吹き込む時間）は、５〜３６０分間であるのが好ましい。 As the non-oxidizing gas, an inert gas such as nitrogen gas or argon gas, or a reducing gas such as hydrogen or carbon monoxide can be used. These gases may be used alone or may be used as a mixed gas which is mixed at a predetermined ratio. The non-oxidizing gas is preferably blown directly into the slurry, but may be blown into (a space above the slurry) in a container (such as a tank or a pipe) that contains the slurry without directly blowing into the slurry. The flow rate of the non-oxidizing gas blown in this way may be a flow rate that can sufficiently reduce the oxygen concentration in the slurry, and is a space above the slurry in a container (such as a tank or a pipe) that contains the slurry. )), the oxygen concentration in the atmosphere in the container (such as a tank or piping) is preferably less than 1% by mass (more preferably less than 0.1% by mass). Good. By reducing the oxygen content in the slurry in this way, it is possible to suppress the oxidation of copper powder (generation of CuO and Cu 2 O). It is considered that when the oxidation of the copper powder is suppressed in this manner, the distortion of the Cu crystal structure can be suppressed, and thus the copper powder thus obtained is coated with a silver coating layer to form a silver-coated copper powder. When the above is manufactured, the crystallite diameter of the silver-coated copper powder on a predetermined crystal plane of Cu can be set to a desired crystallite diameter. In order to suppress the oxidation of such copper powder, the flow rate of the non-oxidizing gas is preferably 10 to 1000 L/min, and the time during which the blowing of the non-oxidizing gas is maintained (in the slurry or the slurry is accommodated (tanks or pipes It is preferable that the time for blowing the non-oxidizing gas into the container (for example,) is 5 to 360 minutes.

銀含有層の被覆量は、銀被覆銅粉に対して１〜５０質量％であるのが好ましく、７〜５０質量％であるのがさらに好ましく、８〜４５質量％であるのがさらに好ましく、９〜４０質量％であるのが最も好ましい。銀含有層の被覆量が１質量％未満では、銀被覆銅粉の導電性に悪影響を及ぼすので好ましくない。一方、５０質量％を超えると、銀の使用量の増加によってコストが高くなるので好ましくない。 The coating amount of the silver-containing layer is preferably from 1 to 50% by mass, more preferably from 7 to 50% by mass, even more preferably from 8 to 45% by mass, based on the silver-coated copper powder. Most preferably, it is 9 to 40% by mass. When the coating amount of the silver-containing layer is less than 1% by mass, the conductivity of the silver-coated copper powder is adversely affected, which is not preferable. On the other hand, if it exceeds 50% by mass, the cost increases due to an increase in the amount of silver used, which is not preferable.

銅粉の粒子径は、（ヘロス法によって）レーザー回折式粒度分布装置により測定した体積基準の累積５０％粒子径（Ｄ５０径）が０．１〜１５μｍであるのが好ましく、０．３〜１０μｍであるのがさらに好ましく、１〜５μｍであるのが最も好ましい。累積５０％粒子径（Ｄ５０径）が０．１μｍ未満では、銀被覆銅粉の導電性に悪影響を及ぼすので好ましくない。一方、１５μｍを超えると、銀被覆銅粉を含む導電性ペーストにより微細な配線を形成するのが困難になるので好ましくない。 The particle size of the copper powder is preferably such that the volume-based cumulative 50% particle size (D 50 size) measured by a laser diffraction type particle size distribution device (by the HEROS method) is 0.1 to 15 μm, and 0.3 to The thickness is more preferably 10 μm, most preferably 1 to 5 μm. If the cumulative 50% particle diameter (D 50 diameter) is less than 0.1 μm, the conductivity of the silver-coated copper powder is adversely affected, which is not preferable. On the other hand, when it exceeds 15 μm, it becomes difficult to form fine wiring with the conductive paste containing silver-coated copper powder, which is not preferable.

また、銅粉中の酸素含有量を低下させるために、溶湯にリンを添加してもよい。このリンの添加量は、溶湯中のリンの濃度が１０〜２０００ｐｐｍになる量であるのが好ましく、４００〜２０００ｐｐｍになる量であるのがさらに好ましい。溶湯にリンを添加するために、溶湯にリン銅合金を添加してもよい。このように溶湯にリンを添加すると、スラリー中の酸素含有量を低減することができ、銅粉の酸化（ＣｕＯやＣｕ２Ｏの生成）を抑制することができる。このように銅粉の酸化を抑制すると、Ｃｕの結晶構造が歪められるのを抑制することができると考えられ、このようにして得られた銅粉を銀被覆層で被覆して銀被覆銅粉を製造すると、銀被覆銅粉のＣｕの所定の結晶面における結晶子径を所望の結晶子径にすることができる。 In addition, phosphorus may be added to the molten metal in order to reduce the oxygen content in the copper powder. The amount of phosphorus added is preferably such that the concentration of phosphorus in the molten metal is 10 to 2000 ppm, more preferably 400 to 2000 ppm. In order to add phosphorus to the molten metal, phosphorus copper alloy may be added to the molten metal. By adding phosphorus to the molten metal in this way, the oxygen content in the slurry can be reduced, and the oxidation of copper powder (generation of CuO and Cu 2 O) can be suppressed. It is considered that when the oxidation of the copper powder is suppressed in this manner, the distortion of the Cu crystal structure can be suppressed, and thus the copper powder thus obtained is coated with a silver coating layer to form a silver-coated copper powder. When the above is manufactured, the crystallite diameter of the silver-coated copper powder on a predetermined crystal plane of Cu can be set to a desired crystallite diameter.

銅粉を銀含有層で被覆する方法として、銅と銀の置換反応を利用した置換法や、還元剤を用いる還元法により、銅粉の表面に銀または銀化合物を析出させる方法を使用することができ、例えば、溶媒中に銅粉と銀または銀化合物を含む溶液を攪拌しながら銅粉の表面に銀または銀化合物を析出させる方法や、溶媒中に銅粉および有機物を含む溶液と溶媒中に銀または銀化合物および有機物を含む溶液とを混合して攪拌しながら銅粉の表面に銀または銀化合物を析出させる方法などを使用することができる。なお、このように銅粉を銀含有層で被覆する工程は、銅粉の酸化を抑制するために、窒素雰囲気などの非酸化性雰囲気で行うのが好ましい。 As a method of coating the copper powder with a silver-containing layer, use a substitution method utilizing a substitution reaction of copper and silver, or a method of depositing silver or a silver compound on the surface of the copper powder by a reduction method using a reducing agent. For example, a method of precipitating silver or a silver compound on the surface of copper powder while stirring a solution containing copper powder and silver or a silver compound in a solvent, or a solution containing a copper powder and an organic substance in a solvent and a solvent. A method of mixing silver or a solution containing a silver compound and an organic substance and precipitating silver or a silver compound on the surface of the copper powder while stirring can be used. The step of coating the copper powder with the silver-containing layer in this manner is preferably performed in a non-oxidizing atmosphere such as a nitrogen atmosphere in order to suppress the oxidation of the copper powder.

この溶媒としては、水、有機溶媒またはこれらを混合した溶媒を使用することができる。水と有機溶媒を混合した溶媒を使用する場合には、室温（２０〜３０℃）において液体になる有機溶媒を使用する必要があるが、水と有機溶媒の混合比率は、使用する有機溶媒により適宜調整することができる。また、溶媒として使用する水は、不純物が混入するおそれがなければ、蒸留水、イオン交換水、工業用水などを使用することができる。 As this solvent, water, an organic solvent, or a mixed solvent thereof can be used. When using a solvent in which water and an organic solvent are mixed, it is necessary to use an organic solvent that becomes a liquid at room temperature (20 to 30° C.), but the mixing ratio of water and the organic solvent depends on the organic solvent used. It can be adjusted appropriately. As water used as a solvent, distilled water, ion-exchanged water, industrial water or the like can be used if there is no risk of impurities being mixed in.

銀含有層の原料として、銀イオンを溶液中に存在させる必要があるため、水や多くの有機溶媒に対して高い溶解度を有する硝酸銀を使用するのが好ましい。また、銅粉を銀含有層で被覆する反応（銀被覆反応）をできるだけ均一に行うために、固体の硝酸銀ではなく、硝酸銀を溶媒（水、有機溶媒またはこれらを混合した溶媒）に溶解した硝酸銀溶液を使用するのが好ましい。なお、使用する硝酸銀溶液の量、硝酸銀溶液中の硝酸銀の濃度および有機溶媒の量は、目的とする銀含有層の量に応じて決定することができる。 Since silver ions must be present in the solution as a raw material for the silver-containing layer, it is preferable to use silver nitrate having a high solubility in water and many organic solvents. Further, in order to perform the reaction of coating the copper powder with the silver-containing layer (silver coating reaction) as uniformly as possible, silver nitrate prepared by dissolving silver nitrate in a solvent (water, an organic solvent or a mixture thereof) is used instead of solid silver nitrate. Preference is given to using solutions. The amount of the silver nitrate solution used, the concentration of silver nitrate in the silver nitrate solution, and the amount of the organic solvent can be determined according to the intended amount of the silver-containing layer.

銀含有層をより均一に形成するために、溶液中にキレート化剤を添加してもよい。キレート化剤としては、銀イオンと金属銅との置換反応により副生する銅イオンなどが再析出しないように、銅イオンなどに対して錯安定度定数が高いキレート化剤を使用するのが好ましい。特に、銀被覆銅粉のコアとなる銅粉は主構成要素が銅であるので、銅との錯安定度定数に留意してキレート化剤を選択するのが好ましい。具体的には、キレート化剤として、エチレンジアミン四酢酸（ＥＤＴＡ）、イミノジ酢酸、ジエチレントリアミン、トリエチレンジアミンおよびこれらの塩からなる群から選ばれたキレート化剤を使用することができる。 A chelating agent may be added to the solution in order to form the silver-containing layer more uniformly. As the chelating agent, it is preferable to use a chelating agent having a high complex stability constant with respect to copper ions and the like so that copper ions and the like that are by-produced by the substitution reaction of silver ions and metallic copper do not reprecipitate. .. In particular, since the main component of the copper powder that is the core of the silver-coated copper powder is copper, it is preferable to select the chelating agent in consideration of the complex stability constant with copper. Specifically, a chelating agent selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), iminodiacetic acid, diethylenetriamine, triethylenediamine and salts thereof can be used as the chelating agent.

銀被覆反応を安定かつ安全に行うために、溶液中にｐＨ緩衝剤を添加してもよい。このｐＨ緩衝剤として、炭酸アンモニウム、炭酸水素アンモニウム、アンモニア水、炭酸水素ナトリウムなどを使用することができる。 A pH buffer may be added to the solution in order to carry out the silver coating reaction stably and safely. As this pH buffer, ammonium carbonate, ammonium hydrogen carbonate, aqueous ammonia, sodium hydrogen carbonate or the like can be used.

銀被覆反応の際には、銀塩を添加する前に溶液中に銅粉を入れて攪拌し、銅粉が溶液中に十分に分散している状態で、銀塩を含む溶液を添加するのが好ましい。この銀被覆反応の際の反応温度は、反応液が凝固または蒸発する温度でなければよいが、好ましくは１０〜４０℃、さらに好ましくは１５〜３５℃の範囲で設定する。また、反応時間は、銀または銀化合物の被覆量や反応温度によって異なるが、１分〜５時間の範囲で設定することができる。 During the silver coating reaction, before adding the silver salt, the copper powder is put in the solution and stirred, and the solution containing the silver salt is added while the copper powder is sufficiently dispersed in the solution. Is preferred. The reaction temperature in this silver coating reaction is not required to be the temperature at which the reaction solution solidifies or evaporates, but is preferably set in the range of 10 to 40°C, more preferably 15 to 35°C. The reaction time can be set within a range of 1 minute to 5 hours, though it varies depending on the coating amount of silver or a silver compound and the reaction temperature.

また、銀含有層で被覆した銅粉を表面処理剤で表面処理するのが好ましく、この表面処理剤が脂肪酸であるのが好ましい。この脂肪酸として、酪酸、吉草酸、カプロン酸、エナント酸、カプリル酸、ペラルゴン酸、カプリン酸、ラウリン酸、ミリスチン酸、ペンタデシル酸、パルミチン酸、パルミトレイン酸、マルガリン酸、ステアリン酸、オレイン酸、バクセン酸、リノール酸、リノレン酸、アラキジン酸、エイコサジエン酸、エイコサトリエン酸、エイコサテトラエン酸、アラキドン酸、ベヘン酸、リグノセリン酸、ネルボン酸、セロチン酸、モンタン酸、メリシン酸などを使用することができるが、パルミチン酸、ステアリン酸またはオレイン酸を使用するのが好ましい。 Further, the copper powder coated with the silver-containing layer is preferably surface-treated with a surface treating agent, and the surface treating agent is preferably a fatty acid. As the fatty acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, pentadecyl acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, vaccenic acid. , Linoleic acid, linolenic acid, arachidic acid, eicosadienoic acid, eicosatrienoic acid, eicosatetraenoic acid, arachidonic acid, behenic acid, lignoceric acid, nervonic acid, cerotic acid, montanic acid, melicinic acid, etc. may be used. However, it is preferred to use palmitic acid, stearic acid or oleic acid.

上述した銀被覆銅粉の製造方法の実施の形態により、本発明による銀被覆銅粉を製造することができる。 The silver-coated copper powder according to the present invention can be manufactured by the embodiment of the method for manufacturing the silver-coated copper powder described above.

本発明による銀被覆銅粉では、銅粉の表面が銀含有層で被覆され、Ｃｕの（２００）面における結晶子径Ｄ（２００）に対するＣｕの（１１１）面における結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２００）が１．８以上であり且つＣｕの（２２０）面における結晶子径Ｄ（２２０）に対するＣｕの（２００）面における結晶子径Ｄ（２００）の比Ｄ（２００）／Ｄ（２２０）が１．０９５以下（好ましくは１．０９以下）である。このような銀被覆銅粉により、体積抵抗率が低く且つ保存安定性（信頼性）に優れた導電膜の製造に適した導電性ペーストを製造することができる。 The silver-coated copper powder according to the present invention, the surface of the copper powder is covered with a silver-containing layer, the crystallite diameter D in (111) plane of Cu with respect to the crystallite diameter D (200) in (200) plane of Cu (111) Ratio D (111) /D (200) of 1.8 or more and the ratio of the crystallite diameter D (200) of the Cu (200) plane to the crystallite diameter D (220) of the Cu (220 ) plane. D (200) /D (220) is 1.095 or less (preferably 1.09 or less). With such silver-coated copper powder, it is possible to manufacture a conductive paste suitable for manufacturing a conductive film having a low volume resistivity and excellent storage stability (reliability).

また、銀被覆銅粉を含む導電性ペーストから製造される導電膜の体積抵抗率および信頼性の観点から、上記の銀被覆銅粉のＣｕの（２２０）面における結晶子径Ｄ（２２０）に対するＣｕの（１１１）面における結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２２０）が１．９０以上であるのが好ましい。 Further, from the viewpoint of volume resistivity and reliability of a conductive film produced from a conductive paste containing silver-coated copper powder, the above-mentioned silver-coated copper powder has a crystallite diameter D (220) on the Cu (220) plane. The ratio D (111) /D (220) of the crystallite diameter D (111) on the (111) plane of Cu is preferably 1.90 or more.

なお、銀被覆銅粉のＣｕの（１１１）面における結晶子径Ｄ（１１１）は、１００〜１６０ｎｍであるのが好ましく、１１０〜１５０ｎｍであるのがさらに好ましい。また、銀被覆銅粉のＣｕの（２００）面における結晶子径Ｄ（２００）は、４０〜９０ｎｍであるのが好ましく、５０〜８０ｎｍであるのがさらに好ましい。さらに、銀被覆銅粉のＣｕの（２２０）面における結晶子径Ｄ（２２０）は、４０〜９０ｎｍであるのが好ましく、５０〜８０ｎｍであるのがさらに好ましい。 The crystallite diameter D (111) on the Cu (111) plane of the silver-coated copper powder is preferably 100 to 160 nm, more preferably 110 to 150 nm. Further, the crystallite diameter D (200) on the (200) plane of Cu of the silver-coated copper powder is preferably 40 to 90 nm, more preferably 50 to 80 nm. Furthermore, the crystallite diameter D (220) on the Cu (220) plane of the silver-coated copper powder is preferably 40 to 90 nm, and more preferably 50 to 80 nm.

また、銀含有層が銀または銀化合物からなる層であるのが好ましく、銀含有層の被覆量は、銀被覆銅粉に対して１〜５０質量％であるのが好ましく、７〜５０質量％であるのがさらに好ましく、８〜４５質量％であるのがさらに好ましく、９〜４０質量％であるのが最も好ましい。銀含有層の被覆量が１質量％未満では、銀被覆銅粉の導電性に悪影響を及ぼすので好ましくない。一方、５０質量％を超えると、銀の使用量の増加によってコストが高くなるので好ましくない。なお、必ずしも銅粉の表面全体が銀含有層で被覆されている必要はない。 Further, the silver-containing layer is preferably a layer made of silver or a silver compound, and the coating amount of the silver-containing layer is preferably 1 to 50% by mass, and 7 to 50% by mass with respect to the silver-coated copper powder. Is more preferable, 8 to 45% by mass is further preferable, and 9 to 40% by mass is most preferable. When the coating amount of the silver-containing layer is less than 1% by mass, the conductivity of the silver-coated copper powder is adversely affected, which is not preferable. On the other hand, if it exceeds 50% by mass, the cost increases due to an increase in the amount of silver used, which is not preferable. The entire surface of the copper powder does not necessarily have to be covered with the silver-containing layer.

銀被覆銅粉の粒子径は、（ヘロス法によって）レーザー回折式粒度分布装置により測定した体積基準の累積５０％粒子径（Ｄ５０径）が０．１〜１５μｍであるのが好ましく、０．３〜１０μｍであるのがさらに好ましく、１〜５μｍであるのが最も好ましい。累積５０％粒子径（Ｄ５０径）が０．１μｍ未満では、銀被覆銅粉の導電性に悪影響を及ぼすので好ましくない。一方、１５μｍを超えると、銀被覆銅粉を含む導電性ペーストにより微細な配線を形成するのが困難になるので好ましくない。 The particle diameter of the silver-coated copper powder is preferably such that the volume-based cumulative 50% particle diameter (D 50 diameter) measured by a laser diffraction type particle size distribution device (by the HEROS method) is 0.1 to 15 μm, and is 0. The thickness is more preferably 3 to 10 μm, most preferably 1 to 5 μm. If the cumulative 50% particle diameter (D 50 diameter) is less than 0.1 μm, the conductivity of the silver-coated copper powder is adversely affected, which is not preferable. On the other hand, when it exceeds 15 μm, it becomes difficult to form fine wiring with the conductive paste containing silver-coated copper powder, which is not preferable.

銀被覆銅粉のＢＥＴ比表面積は、銀被覆銅粉の導電性の観点から、０．１〜４ｍ２／ｇであるのが好ましく、０．２〜３ｍ２／ｇであるのがさらに好ましい。銀被覆銅粉のタップ密度は、銀被覆銅粉の充填性の観点から、４〜７．５ｇ／ｃｍ３であるのが好ましく、４．５〜７ｇ／ｃｍ３であるのがさらに好ましい。銀被覆銅粉中の酸素含有量は、銀被覆銅粉の導電性の観点から、０．４質量％以下であるのが好ましく、０．３質量％以下であるのがさらに好ましい。銀被覆銅粉中の炭素含有量は、銀被覆銅粉を含む導電性ペーストとその導電性ペーストを塗布する基板との密着性の観点から、０．３質量％以下であるのが好ましく、０．２質量％以下であるのが好ましい。銀被覆銅粉中のリン含有量は、銀被覆銅粉を含む導電性ペーストから製造される導電膜の体積抵抗率および信頼性の観点から、１０〜１０００ｐｐｍであるのが好ましく、２００〜５００ｐｐｍであるのがさらに好ましい。銀被覆銅粉の形状は、水アトマイズ法により製造された形状である略球状でもよいが、機械的に変形させてフレーク状にしてもよい。 The BET specific surface area of the silver-coated copper powder is preferably 0.1 to 4 m 2 /g, and more preferably 0.2 to 3 m 2 /g from the viewpoint of the conductivity of the silver-coated copper powder. The tap density of the silver-coated copper powder is preferably 4 to 7.5 g/cm 3 , and more preferably 4.5 to 7 g/cm 3 from the viewpoint of the filling property of the silver-coated copper powder. From the viewpoint of conductivity of the silver-coated copper powder, the oxygen content in the silver-coated copper powder is preferably 0.4% by mass or less, and more preferably 0.3% by mass or less. The carbon content in the silver-coated copper powder is preferably 0.3% by mass or less from the viewpoint of the adhesiveness between the conductive paste containing the silver-coated copper powder and the substrate to which the conductive paste is applied, and is 0% by mass or less. It is preferably 0.2% by mass or less. The phosphorus content in the silver-coated copper powder is preferably 10 to 1000 ppm, and preferably 200 to 500 ppm, from the viewpoint of volume resistivity and reliability of the conductive film produced from the conductive paste containing the silver-coated copper powder. It is more preferable that there is. The shape of the silver-coated copper powder may be a substantially spherical shape, which is a shape produced by the water atomizing method, or may be mechanically deformed into a flake shape.

本発明による銀被覆銅粉の実施の形態は、（銀被覆銅粉を有機成分中に分散させた）導電性ペーストの材料などに使用することができる。導電性ペーストの構成要素として、銀被覆銅粉、（エチルセルロース樹脂、アクリル樹脂、エポキシ樹脂、フェノール樹脂、ブチラール樹脂などの）バインダー樹脂またはこのバインダー樹脂を有機溶剤に溶解したビヒクル、ガラスフリット、無機酸化物、（飽和または不飽和脂肪族炭化水素類、ケトン類、芳香族炭化水素類、グリコールエーテル類、エステル類、アルコール類などの）有機溶剤、分散剤、硬化剤などが含まれる。このような導電性ペーストは、各構成要素を計量して所定の容器に入れ、らいかい機、万能攪拌機、ニーダーなどを用いて予備混練した後、３本ロールで本混練することによって作製することができる。また、必要に応じて、その後、溶剤を添加して、粘度調整を行ってもよい。また、ガラスフリットや無機酸化物とビヒクルのみを本混練して粒度を下げた後、最後に銀被覆銅粉を追加して本混練してもよい。なお、導電性ペーストの導電性粉末として、他の金属粉末を配合してもよい。この導電性ペーストをディッピングや印刷などにより所定パターンに形成した後に焼成して導電膜を形成することができる。 The embodiment of the silver-coated copper powder according to the present invention can be used as a material for a conductive paste (in which silver-coated copper powder is dispersed in an organic component) or the like. As components of the conductive paste, silver-coated copper powder, binder resin (such as ethyl cellulose resin, acrylic resin, epoxy resin, phenol resin, butyral resin) or a vehicle in which this binder resin is dissolved in an organic solvent, glass frit, inorganic oxidation Substances, organic solvents (such as saturated or unsaturated aliphatic hydrocarbons, ketones, aromatic hydrocarbons, glycol ethers, esters and alcohols), dispersants, curing agents and the like. Such a conductive paste is prepared by weighing each component into a predetermined container, preliminarily kneading with a ladle machine, universal stirrer, kneader, etc., and then main kneading with a three-roll mill. You can If necessary, a solvent may be added thereafter to adjust the viscosity. Alternatively, only the glass frit or the inorganic oxide and the vehicle may be main-kneaded to reduce the particle size, and finally silver-coated copper powder may be added to the main-kneading. In addition, you may mix|blend another metal powder as electroconductive powder of electroconductive paste. This conductive paste can be formed into a predetermined pattern by dipping, printing, or the like and then baked to form a conductive film.

本発明による銀被覆銅粉の実施の形態を含む導電性ペーストから得られた導電膜の体積抵抗率は、２０〜５５μΩ・ｃｍであるのが好ましく、２０〜４５μΩ・ｃｍであるのがさらに好ましい。また、この導電膜を一定温度（１５０℃）に保たれた（大気雰囲気の）試験室内において６週間保存した後の導電膜の体積抵抗率の変化率は、１２０％以下であるのが好ましく、１００％以下であるのがさらに好ましい。 The volume resistivity of the conductive film obtained from the conductive paste including the embodiment of the silver-coated copper powder according to the present invention is preferably 20 to 55 μΩ·cm, more preferably 20 to 45 μΩ·cm. .. The rate of change in volume resistivity of the conductive film after being stored for 6 weeks in a test room (in air atmosphere) kept at a constant temperature (150° C.) is preferably 120% or less, It is more preferably 100% or less.

以下、本発明による銀被覆銅粉およびその製造方法の実施例について詳細に説明する。 Hereinafter, examples of the silver-coated copper powder and the method for producing the same according to the present invention will be described in detail.

［実施例１］
無酸素銅１５ｋｇを加熱して溶解した１３００℃の溶湯中に（１５質量％のリンを含む）リン銅合金を（溶湯中の）リン濃度が９３０ｐｐｍになるように添加して撹拌し、混合することにより作製したリン含有銅溶湯をタンディッシュ下部から落下させながら、水アトマイズ装置により大気中において水圧１５０ＭＰａで高圧水を吹き付けて急冷凝固させ、得られたスラリーをタンク内に収容し、スラリー中に５００Ｌ／分の流量で窒素ガスを吹き込んで３０分間保持した後、固液分離し、固形物を水洗し、１１０℃で１０時間乾燥し、解砕し、風力分級して、少量のリンを含む銅粉を得た。なお、窒素ガスを吹き込んで保持したときのタンク内の雰囲気中の酸素濃度は０．１質量％未満であった。また、高圧水として、高圧ポンプに給水するタンク中の純水に水酸化ナトリウムを添加して得られたｐＨ１０．３のアルカリ水溶液を使用した。 [Example 1]
Phosphorous copper alloy (containing 15% by mass of phosphorus) is added to a molten metal of 1300° C. obtained by heating and melting 15 kg of oxygen-free copper so that the phosphorus concentration (in the molten metal) is 930 ppm, and the mixture is stirred and mixed. While dropping the phosphorus-containing copper melt produced by the above from the lower part of the tundish, high-pressure water was sprayed at a water pressure of 150 MPa in the atmosphere by a water atomizer to rapidly solidify, and the resulting slurry was stored in a tank and placed in a slurry. After blowing nitrogen gas at a flow rate of 500 L/min and holding for 30 minutes, solid-liquid separation is performed, solid matter is washed with water, dried at 110° C. for 10 hours, crushed, air-classified, and contains a small amount of phosphorus. I got copper powder. The oxygen concentration in the atmosphere in the tank when nitrogen gas was blown and held was less than 0.1% by mass. Further, as the high pressure water, an alkaline aqueous solution having a pH of 10.3 obtained by adding sodium hydroxide to pure water in a tank for supplying water to the high pressure pump was used.

また、ＥＤＴＡ−２Ｎａ二水和物１６７ｇと炭酸アンモニウム１６７ｇを純水１９３６ｇに溶解した溶液（溶液１）と、ＥＤＴＡ−２Ｎａ二水和物３６７ｇと炭酸アンモニウム１８４ｇを純水１４６４ｇに溶解した溶液に、硝酸銀６１ｇを純水１８９ｇに溶解した溶液を加えて得られた溶液（溶液２）を用意した。 In addition, a solution (solution 1) in which 167 g of EDTA-2Na dihydrate and 167 g of ammonium carbonate were dissolved in 1936 g of pure water, and a solution of 367 g of EDTA-2Na dihydrate and 184 g of ammonium carbonate in 1464 g of pure water, A solution (solution 2) obtained by adding a solution prepared by dissolving 61 g of silver nitrate in 189 g of pure water was prepared.

次に、窒素雰囲気下において、得られた銅粉３５０ｇを溶液１に加えて、攪拌しながら２５℃まで昇温させた。この銅粉が分散した溶液に溶液２を加えて２０分間撹拌することにより、銀により被覆された銅粉を含むスラリーを得た。 Next, in a nitrogen atmosphere, 350 g of the obtained copper powder was added to the solution 1, and the temperature was raised to 25° C. with stirring. Solution 2 was added to the solution in which the copper powder was dispersed and stirred for 20 minutes to obtain a slurry containing the copper powder coated with silver.

次に、得られたスラリーに、表面処理剤としてパルミチン酸をアルコールに溶解させて得られた（３質量％のパルミチン酸を含む）溶液３５ｇを添加し、４０分間撹拌した後、濾過し、水洗し、真空雰囲気中において７０℃で乾燥し、得られた乾燥粉末８０ｇをミル（メリタジャパン株式会社製のセレクトグラインドＭＪ−５１８）に入れ、２０秒間の粉砕処理を２回行って解砕し、篩別して、銀被覆銅粉末を得た。 Next, 35 g of a solution (containing 3% by mass of palmitic acid) obtained by dissolving palmitic acid in alcohol as a surface treatment agent was added to the obtained slurry, stirred for 40 minutes, filtered, and washed with water. Then, it was dried at 70° C. in a vacuum atmosphere, and 80 g of the obtained dry powder was put into a mill (Select Grind MJ-518 manufactured by Melita Japan Co., Ltd.) and crushed twice for 20 seconds to disintegrate, It sieved and obtained the silver coating copper powder.

このようにして得られた銀被覆銅粉のＢＥＴ比表面積、タップ密度（ＴＡＰ）、銀の被覆量、銀被覆層の厚さ、酸素含有量、炭素含有量、リン含有量および粒度分布を求めた。また、銀被覆前の銅粉の平均粒径、ＢＥＴ比表面積、酸素含有量およびリン含有量を求めた。 The BET specific surface area, tap density (TAP), silver coating amount, silver coating layer thickness, oxygen content, carbon content, phosphorus content and particle size distribution of the silver-coated copper powder thus obtained were determined. It was Further, the average particle size, BET specific surface area, oxygen content and phosphorus content of the copper powder before silver coating were determined.

銀被覆前の銅粉の平均粒径として、レーザー回折式粒度分布装置（ＳＹＭＰＡＴＥＣ社製のへロス粒度分布測定装置（ＨＥＬＯＳ＆ＲＯＤＯＳ（気流式の乾燥モジュール）））により分散圧５ｂａｒで測定した体積基準の累積５０％粒子径（Ｄ５０径）を求めたところ、２．０μｍであった。 The average particle size of the copper powder before silver coating is based on a volume measured at a dispersion pressure of 5 bar by a laser diffraction type particle size distribution device (HELOS & RODOS (air flow type drying module)) manufactured by SYMPATEC. The cumulative 50% particle size (D 50 size) was determined to be 2.0 μm.

銀被覆前の銅粉のＢＥＴ比表面積は、測定器内に１０５℃で２０分間窒素ガスを流して脱気した後、ＢＥＴ比表面積測定器（ユアサアイオニクス株式会社製の４ソーブＵＳ）を使用してＢＥＴ１点法により測定した。その結果、ＢＥＴ比表面積は０．５８ｍ２／ｇであった。 For the BET specific surface area of the copper powder before silver coating, use a BET specific surface area measuring instrument (4Sorb US manufactured by Yuasa Ionics Co., Ltd.) after degassing by flowing nitrogen gas at 105° C. for 20 minutes in the measuring instrument. Then, it was measured by the BET one point method. As a result, the BET specific surface area was 0.58 m 2 /g.

銀被覆前の銅粉中の酸素含有量は、酸素・窒素分析装置（株式会社堀場製作所製のＥＭＧＡ−９２０）により測定した。その結果、酸素含有量は０．２４質量％であった。 The oxygen content in the copper powder before silver coating was measured by an oxygen/nitrogen analyzer (EMGA-920 manufactured by Horiba, Ltd.). As a result, the oxygen content was 0.24% by mass.

銀被覆前の銅粉中のリン含有量は、ＩＣＰ発光分光分析装置（株式会社日立ハイテクサイエンス製のＳＰＳ３５２０Ｖ）により測定した。その結果、リン含有量は４７０ｐｐｍであった。 The phosphorus content in the copper powder before silver coating was measured by an ICP emission spectroscopy analyzer (SPS3520V manufactured by Hitachi High-Tech Science Co., Ltd.). As a result, the phosphorus content was 470 ppm.

銀被覆銅粉のＢＥＴ比表面積は、銀被覆前の銅粉のＢＥＴ比表面積と同様の方法により求めた。その結果、ＢＥＴ比表面積は０．４３ｍ２／ｇであった。 The BET specific surface area of the silver-coated copper powder was determined by the same method as the BET specific surface area of the copper powder before silver coating. As a result, the BET specific surface area was 0.43 m 2 /g.

銀被覆銅粉のタップ密度（ＴＡＰ）は、特開２００７−２６３８６０号公報に記載された方法と同様に、銀被覆銅粉０．５ｇを内径６ｍｍの有底円筒形のダイに充填して銀被覆銅粉層を形成し、この銀被覆銅粉層の上面に０．１６０Ｎ／ｍ２の圧力を均一に加えた後、銀被覆銅粉層の高さを測定し、この銀被覆銅粉層の高さの測定値と、充填された銀被覆銅粉の重量とから、銀被覆銅粉の密度を求めて、銀被覆銅粉のタップ密度とした。その結果、タップ密度は５．８ｇ／ｃｍ３であった。 The tap density (TAP) of the silver-coated copper powder is the same as in the method described in JP 2007-263860 A, when 0.5 g of the silver-coated copper powder is filled in a bottomed cylindrical die having an inner diameter of 6 mm. After forming a coated copper powder layer and uniformly applying a pressure of 0.160 N/m 2 to the upper surface of this silver-coated copper powder layer, the height of the silver-coated copper powder layer was measured, and this silver-coated copper powder layer was measured. The density of the silver-coated copper powder was determined from the measured value of the height and the weight of the filled silver-coated copper powder, and was defined as the tap density of the silver-coated copper powder. As a result, the tap density was 5.8 g/cm 3 .

銀被覆銅粉の銀の被覆量は、銀被覆銅粉（約２．５ｇ）を塩化ビニル製リング（内径３．２ｃｍ×厚さ４ｍｍ）内に敷き詰めた後、錠剤型成型圧縮機（株式会社前川試験製作所製の型番ＢＲＥ−５０）により１００ｋＮの荷重をかけて銀被覆銅粉のペレットを作製し、このペレットをサンプルホルダー（開口径３．０ｃｍ）に入れて蛍光Ｘ線分析装置（株式会社リガク製のＲＩＸ２０００）内の測定位置にセットし、測定雰囲気を減圧下（８．０Ｐａ）とし、Ｘ線出力を５０ｋＶ、５０ｍＡとした条件で測定した結果から、装置に付属のソフトウェアで自動計算することによって求めた。その結果、銀被覆銅粉中の銀の被覆量は１０．３質量％であった。 The silver coating amount of silver-coated copper powder was obtained by spreading silver-coated copper powder (about 2.5 g) in a vinyl chloride ring (internal diameter 3.2 cm x thickness 4 mm), and then using a tablet-type molding compressor (Co., Ltd.). A pellet of silver-coated copper powder was prepared by applying a load of 100 kN with a Maekawa Test Co., Ltd. model number BRE-50), and the pellet was placed in a sample holder (opening diameter 3.0 cm) to obtain a fluorescent X-ray analyzer (Co. RIX2000 manufactured by Rigaku is set at the measurement position, the measurement atmosphere is under reduced pressure (8.0 Pa), and the X-ray output is 50 kV and 50 mA. From the measurement results, the software attached to the device automatically calculates. Sought by. As a result, the coating amount of silver in the silver-coated copper powder was 10.3% by mass.

銀被覆層の厚さは、銀被覆層の厚さ（ｎｍ）＝｛銀の被覆量（質量％）×１０｝／｛ＢＥＴ比表面積（ｍ２／ｇ）×１０．４９｝から求めた。その結果、銀被覆層の厚さは３０ｎｍであった。 The thickness of the silver coating layer was calculated from the thickness of the silver coating layer (nm)={silver coating amount (mass %)×10}/{BET specific surface area (m 2 /g)×10.49}. As a result, the thickness of the silver coating layer was 30 nm.

銀被覆銅粉中の酸素含有量は、酸素・窒素分析装置（株式会社堀場製作所製のＥＭＧＡ−９２０）により測定した。その結果、酸素含有量は０．１３質量％であった。 The oxygen content in the silver-coated copper powder was measured by an oxygen/nitrogen analyzer (EMGA-920 manufactured by Horiba, Ltd.). As a result, the oxygen content was 0.13% by mass.

銀被覆銅粉中の炭素含有量は、炭素・硫黄分析装置（株式会社堀場製作所製のＥＭＩＡ−２２０Ｖ）により測定した。その結果、炭素含有量は０．１８質量％であった。 The carbon content in the silver-coated copper powder was measured by a carbon/sulfur analyzer (EMIA-220V manufactured by Horiba Ltd.). As a result, the carbon content was 0.18% by mass.

銀被覆銅粉中のリン含有量は、銀被覆前の銅粉のリン含有量と同様の方法により求めた。その結果、リン含有量は３８０ｐｐｍであった。 The phosphorus content in the silver-coated copper powder was determined by the same method as the phosphorus content in the copper powder before silver coating. As a result, the phosphorus content was 380 ppm.

銀被覆銅粉の粒度分布として、銅被覆前の銅粉の平均粒径を測定したレーザー回折式粒度分布装置と同様のレーザー回折式粒度分布装置により測定した体積基準の累積１０％粒子径（Ｄ１０径）、累積５０％粒子径（Ｄ５０径）および累積９０％粒子径（Ｄ９０径）を求めた。その結果、累積１０％粒子径（Ｄ１０径）は０．６μｍ、累積５０％粒子径（Ｄ５０径）は２．０μｍ、累積９０％粒子径（Ｄ９０径）は３．９μｍであった。 As the particle size distribution of the silver-coated copper powder, a volume-based cumulative 10% particle size (D) measured by a laser diffraction-type particle size distribution device similar to the laser diffraction-type particle size distribution device that measured the average particle size of the copper powder before copper coating 10 diameter), cumulative 50% particle diameter (D 50 diameter) and cumulative 90% particle diameter (D 90 diameter) were determined. As a result, the cumulative 10% particle diameter (D 10 diameter) was 0.6 μm, the cumulative 50% particle diameter (D 50 diameter) was 2.0 μm, and the cumulative 90% particle diameter (D 90 diameter) was 3.9 μm. ..

また、得られた銀被覆銅粉について、Ｘ線回折装置（株式会社リガク製のＲＩＮＴ Ｕｌｔｉｍａ ＩＩＩ）によりＣｏ線源（４０ｋＶ／３０ｍＡ）で、Ｃｕの（１１１）面については４９〜５３°／２θの範囲、Ｃｕの（２００）面については５８〜６１°／２θの範囲、Ｃｕの（２２０）面については８７〜９１°／２θの範囲を測定して、Ｘ線回折（ＸＲＤ）の評価を行った。このＸ線回折パターンから得られたＣｕの（１１１）面の半価幅βを用いて、Ｓｃｈｅｒｒｅｒの式Ｄ＝（Ｋ・λ）／（β・ｃｏｓθ）からＣｕの（１１１）面における結晶子径Ｄ（１１１）を算出したところ、結晶子径Ｄ（１１１）は１４２ｎｍであった。なお、Ｓｃｈｅｒｒｅｒの式において、Ｄは結晶子径（ｎｍ）、λは測定Ｘ線波長（ｎｍ）、βは結晶子による回折幅の広がり、θは回折角のブラッグ角、ＫはＳｃｈｅｒｒｅｒ定数を示し、この式中の測定Ｘ線波長λを０．１７９ｎｍ、Ｓｃｈｅｒｒｅｒ定数Ｋを０．９０とした。同様に、Ｘ線回折パターンから得られたＣｕの（２００）面および（２２０）面のそれぞれの半値幅βを用いて、Ｓｃｈｅｒｒｅｒの式からＣｕの（２００）面および（２２０）面における結晶子径Ｄ（２００）およびＤ（２２０）を算出したところ、結晶子径Ｄ（２００）は７６ｎｍであり、結晶子径Ｄ（２２０）は７０ｎｍであった。これらの結果から、結晶子径Ｄ（２００）に対する結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２００）は１．８７、結晶子径Ｄ（２２０）に対する結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２２０）は２．０３、結晶子径Ｄ（２２０）に対する結晶子径Ｄ（２００）の比Ｄ（２００）／Ｄ（２２０）は１．０９になる。 Moreover, about the obtained silver-coated copper powder, it was a Co ray source (40 kV/30 mA) by an X-ray diffractometer (RINT Ultima III manufactured by Rigaku Corporation), and the Cu (111) plane was 49 to 53°/2θ. , The range of 58 to 61°/2θ for the (200) plane of Cu, and the range of 87 to 91°/2θ for the (220) plane of Cu were measured to evaluate the X-ray diffraction (XRD). went. Using the half-value width β of the (111) plane of Cu obtained from this X-ray diffraction pattern, the crystallite on the (111) plane of Cu was calculated from Scherrer's equation D=(K·λ)/(β·cos θ). When the diameter D (111) was calculated, the crystallite diameter D (111) was 142 nm. In the Scherrer's equation, D is the crystallite diameter (nm), λ is the measured X-ray wavelength (nm), β is the spread of the diffraction width by the crystallite, θ is the Bragg angle of the diffraction angle, and K is the Scherrer constant. The measured X-ray wavelength λ in this formula was 0.179 nm, and the Scherrer constant K was 0.90. Similarly, using the respective half-value widths β of the (200) plane and the (220) plane of Cu obtained from the X-ray diffraction pattern, the crystallites on the (200) plane and (220) plane of Cu can be calculated from Scherrer's equation. When the diameters D (200) and D (220) were calculated, the crystallite diameter D (200) was 76 nm and the crystallite diameter D (220) was 70 nm. These results, the crystallite diameter D (200) ratio D of the crystallite diameter D (111) for (111) / D (200) is 1.87, and the crystallite diameter D (111 for the crystallite diameter D (220) the ratio D of) (111) / D (220 ) is 2.03, the ratio D of the crystallite diameter D for the crystallite diameter D (220) (200) ( 200) / D (220) becomes 1.09.

次に、得られた銀被覆銅粉９．３ｇと、熱硬化型樹脂としてビスフェノールＦ型エポキシ樹脂（株式会社ＡＤＥＫＡ製のアデカレジンＥＰ−４９０１Ｅ）０．８２ｇと、硬化剤として三フッ化ホウ素モノエチルアミン０．０４１ｇと、溶剤としてブチルカルビトールアセテート０．２５ｇと、分散剤としてオレイン酸０．０１ｇとを混練脱泡機で混合した後、三本ロールを５回パスして均一に分散させることによって導電性ペーストを得た。 Next, 9.3 g of the obtained silver-coated copper powder, 0.82 g of a bisphenol F type epoxy resin (ADEKA Resin EP-4901E manufactured by ADEKA Co., Ltd.) as a thermosetting resin, and boron trifluoride monoethylamine as a curing agent. By mixing 0.041 g, 0.25 g of butyl carbitol acetate as a solvent, and 0.01 g of oleic acid as a dispersant with a kneading and defoaming machine, three rolls are passed 5 times to uniformly disperse the mixture. A conductive paste was obtained.

この導電性ペーストをスクリーン印刷法によってアルミナ基板上に（線幅５００μｍ、線長３７．５ｍｍのパターンに）印刷した後、大気中において２００℃で４０分間加熱して硬化させることによって導電膜を形成し、得られた導電膜の体積抵抗率の算出と保存安定性（信頼性）の評価を行った。 A conductive film is formed by printing this conductive paste on an alumina substrate (in a pattern having a line width of 500 μm and a line length of 37.5 mm) by screen printing, and then heating and curing at 200° C. for 40 minutes in the atmosphere. Then, the volume resistivity of the obtained conductive film was calculated and the storage stability (reliability) was evaluated.

導電膜の体積抵抗率は、得られた導電膜のライン抵抗をデジタルマルチメーター（株式会社エーディーシー製のＡＤ７４５１Ａ）により測定し、膜厚を表面粗さ形状測定機（株式会社東京精密製のサーフコム１５００ＤＸ型）により測定して、体積抵抗率（Ω・ｃｍ）＝ライン抵抗（Ω）×膜厚（ｃｍ）×線幅（ｃｍ）／線長（ｃｍ）により算出した。その結果、導電膜の初期の）体積抵抗率は３５μΩ・ｃｍであった。 The volume resistivity of the conductive film is obtained by measuring the line resistance of the obtained conductive film with a digital multimeter (AD7451A manufactured by ADC Co., Ltd.) and measuring the film thickness by a surface roughness profiler (Surfcom manufactured by Tokyo Seimitsu Co., Ltd.). The volume resistivity (Ω·cm)=line resistance (Ω)×film thickness (cm)×line width (cm)/line length (cm). As a result, the initial volume resistivity of the conductive film was 35 μΩ·cm.

導電膜の保存安定性（信頼性）は、一定温度（１５０℃）に保たれた（大気雰囲気の）試験室内において６週間保存した導電膜の体積抵抗率（６週間保存後の体積抵抗率）を算出し、体積抵抗率の変化率（％）＝｛（６週間保存後の体積抵抗率）−（初期の体積抵抗率）｝×１００／（初期の体積抵抗率）によって評価した。その結果、６週間保存後の体積抵抗率は５４μΩ・ｃｍであり、体積抵抗率の変化率は５４％であった。 The storage stability (reliability) of the conductive film is the volume resistivity of the conductive film stored for 6 weeks in a test room (atmosphere atmosphere) kept at a constant temperature (150°C) (volume resistivity after storage for 6 weeks). Was calculated and evaluated by the rate of change in volume resistivity (%)={(volume resistivity after 6 weeks storage)-(initial volume resistivity)}×100/(initial volume resistivity). As a result, the volume resistivity after storage for 6 weeks was 54 μΩ·cm, and the rate of change in volume resistivity was 54%.

［実施例２］
ＥＤＴＡ−２Ｎａ二水和物１４３ｇと炭酸アンモニウム１４３ｇを純水１６６２ｇに溶解した溶液（溶液１）と、ＥＤＴＡ−２Ｎａ二水和物４０５ｇと炭酸アンモニウム２０２ｇを純水１６１３ｇに溶解した溶液に、硝酸銀６７ｇを純水２０９ｇに溶解した溶液を加えて得られた溶液（溶液２）を用意した。 [Example 2]
A solution of 143 g of EDTA-2Na dihydrate and 143 g of ammonium carbonate dissolved in 1662 g of pure water (solution 1), a solution of 405 g of EDTA-2Na dihydrate and 202 g of ammonium carbonate dissolved in 1613 g of pure water, and 67 g of silver nitrate A solution (solution 2) obtained by adding a solution prepared by dissolving 209 g in pure water was prepared.

次に、窒素雰囲気下において、実施例１と同様の方法により得られた銅粉３００ｇを溶液１に加えて、攪拌しながら２５℃まで昇温させた。この銅粉が分散した溶液に溶液２を加えて２０分間撹拌することにより、銀により被覆された銅粉を含むスラリーを得た。 Next, in a nitrogen atmosphere, 300 g of copper powder obtained by the same method as in Example 1 was added to Solution 1, and the temperature was raised to 25° C. with stirring. Solution 2 was added to the solution in which the copper powder was dispersed, and the mixture was stirred for 20 minutes to obtain a slurry containing the copper powder coated with silver.

次に、得られたスラリーに、表面処理剤としてオレイン酸をアルコールに溶解させて得られた（３質量％のオレイン酸を含む）溶液３０ｇを添加し、４０分間撹拌した後、濾過し、水洗し、真空雰囲気中において７０℃で乾燥し、得られた乾燥粉末８０ｇをミル（メリタジャパン株式会社製のセレクトグラインドＭＪ−５１８）に入れ、２０秒間の粉砕処理を２回行って解砕し、篩別して、銀被覆銅粉末を得た。 Next, 30 g of a solution (containing 3% by mass of oleic acid) obtained by dissolving oleic acid in alcohol as a surface treatment agent was added to the obtained slurry, stirred for 40 minutes, filtered, and washed with water. Then, it was dried at 70° C. in a vacuum atmosphere, and 80 g of the obtained dry powder was put into a mill (Select Grind MJ-518 manufactured by Melita Japan Co., Ltd.) and crushed twice for 20 seconds to disintegrate, It sieved and obtained the silver coating copper powder.

このようにして得られた銀被覆銅粉について、実施例１と同様の方法により、ＢＥＴ比表面積、タップ密度（ＴＡＰ）、銀の被覆量、銀被覆層の厚さ、酸素含有量、炭素含有量、リン含有量および粒度分布を求めるとともに、Ｘ線回折の評価を行った。また、銀被覆前の銅粉について、実施例１と同様の方法により、平均粒径、ＢＥＴ比表面積、酸素含有量およびリン含有量を求めた。 With respect to the silver-coated copper powder thus obtained, the BET specific surface area, tap density (TAP), silver coating amount, silver coating layer thickness, oxygen content, carbon content were measured in the same manner as in Example 1. The amount, phosphorus content and particle size distribution were determined, and the X-ray diffraction was evaluated. The average particle size, BET specific surface area, oxygen content and phosphorus content of the copper powder before silver coating were determined by the same method as in Example 1.

その結果、銀被覆前の銅粉の平均粒径は２．０μｍ、ＢＥＴ比表面積は０．５８ｍ２／ｇ、酸素含有量は０．２４質量％、リン含有量は４７０ｐｐｍであった。また、銀被覆銅粉のＢＥＴ比表面積は０．４０ｍ２／ｇ、タップ密度は５．７ｇ／ｃｍ３、銀の被覆量は１３．２質量％、銀被覆層の厚さは４０ｎｍ、酸素含有量は０．１４質量％、炭素含有量は０．１５質量％、リン含有量は４５０ｐｐｍであった。また、銀被覆銅粉の累積１０％粒子径（Ｄ１０径）は０．７μｍ、累積５０％粒子径（Ｄ５０径）は２．１μｍ、累積９０％粒子径（Ｄ９０径）は４．０μｍであった。また、結晶子径Ｄ（１１１）は１２４ｎｍ、結晶子径Ｄ（２００）は６２ｎｍ、結晶子径Ｄ（２２０）は６４ｎｍであり、Ｄ（１１１）／Ｄ（２００）は２．００、Ｄ（１１１）／Ｄ（２２０）は１．９４、Ｄ（２００）／Ｄ（２２０）は０．９７であった。 As a result, the average particle diameter of the copper powder before silver coating was 2.0 μm, the BET specific surface area was 0.58 m 2 /g, the oxygen content was 0.24% by mass, and the phosphorus content was 470 ppm. The BET specific surface area of the silver-coated copper powder is 0.40 m 2 /g, the tap density is 5.7 g/cm 3 , the silver coating amount is 13.2% by mass, the silver coating layer thickness is 40 nm, and the oxygen content is The amount was 0.14% by mass, the carbon content was 0.15% by mass, and the phosphorus content was 450 ppm. The cumulative 10% particle diameter (D 10 diameter) of the silver-coated copper powder was 0.7 μm, the cumulative 50% particle diameter (D 50 diameter) was 2.1 μm, and the cumulative 90% particle diameter (D 90 diameter) was 4. It was 0 μm. The crystallite diameter D (111) is 124 nm, the crystallite diameter D (200) is 62 nm, the crystallite diameter D (220) is 64 nm, and D (111) /D (200) is 2.00 and D ( 111) /D (220) was 1.94 and D (200) /D (220) was 0.97.

また、得られた銀被覆銅粉を使用して、実施例１と同様の方法により、導電性ペーストを作製して導電膜を形成し、得られた導電膜の体積抵抗率の算出と保存安定性（信頼性）の評価を行った。その結果、導電膜の初期の体積抵抗率は２７μΩ・ｃｍ、６週間保存後の体積抵抗率は４１μΩ・ｃｍであり、体積抵抗率の変化率は５２％であった。 Further, using the obtained silver-coated copper powder, a conductive paste was prepared in the same manner as in Example 1 to form a conductive film, and the volume resistivity of the obtained conductive film was calculated and the storage stability was improved. The reliability (reliability) was evaluated. As a result, the initial volume resistivity of the conductive film was 27 μΩ·cm, the volume resistivity after storage for 6 weeks was 41 μΩ·cm, and the change rate of the volume resistivity was 52%.

［実施例３］
溶湯中のリン濃度が９５０ｐｐｍになるようにリン銅合金を添加し、溶湯の温度を１６００℃とし、高圧水として、高圧ポンプに給水するタンク中の純水に水酸化ナトリウムを添加して得られたｐＨ１０．７のアルカリ水溶液を使用した以外は、実施例１と同様の方法により、少量のリンを含む銅粉を得た。 [Example 3]
It was obtained by adding phosphorus copper alloy so that the phosphorus concentration in the molten metal would be 950 ppm, adjusting the temperature of the molten metal to 1600° C., and adding sodium hydroxide to the pure water in the tank for supplying high pressure water as high pressure water. A copper powder containing a small amount of phosphorus was obtained by the same method as in Example 1 except that an alkaline aqueous solution having a pH of 10.7 was used.

また、ＥＤＴＡ−２Ｎａ二水和物１１９ｇと炭酸アンモニウム１１９ｇを純水１３８５ｇに溶解した溶液（溶液１）と、ＥＤＴＡ−２Ｎａ二水和物５９１ｇと炭酸アンモニウム２９５ｇを純水２３５２ｇに溶解した溶液に、硝酸銀９８ｇを純水３０４ｇに溶解した溶液を加えて得られた溶液（溶液２）を用意した。 Further, a solution (solution 1) prepared by dissolving 119 g of EDTA-2Na dihydrate and 119 g of ammonium carbonate in 1385 g of pure water, and a solution prepared by dissolving 591 g of EDTA-2Na dihydrate and 295 g of ammonium carbonate in 2352 g of pure water, A solution (solution 2) obtained by adding a solution of 98 g of silver nitrate dissolved in 304 g of pure water was prepared.

次に、窒素雰囲気下において、得られた銅粉２５０ｇを溶液１に加えて、攪拌しながら２５℃まで昇温させた。この銅粉が分散した溶液に溶液２を加えて２０分間撹拌することにより、銀により被覆された銅粉を含むスラリーを得た。 Next, in a nitrogen atmosphere, 250 g of the obtained copper powder was added to the solution 1, and the temperature was raised to 25° C. with stirring. Solution 2 was added to the solution in which the copper powder was dispersed and stirred for 20 minutes to obtain a slurry containing the copper powder coated with silver.

次に、得られたスラリーに、表面処理剤としてパルミチン酸をアルコールに溶解させて得られた（３質量％のパルミチン酸を含む）溶液２５ｇを添加し、４０分間撹拌した後、濾過し、水洗し、真空雰囲気中において７０℃で乾燥し、得られた乾燥粉末８０ｇをミル（メリタジャパン株式会社製のセレクトグラインドＭＪ−５１８）に入れ、２０秒間の粉砕処理を２回行って解砕し、篩別して、銀被覆銅粉末を得た。 Next, 25 g of a solution (containing 3% by mass palmitic acid) obtained by dissolving palmitic acid in alcohol as a surface treatment agent was added to the obtained slurry, stirred for 40 minutes, filtered, and washed with water. Then, it was dried at 70° C. in a vacuum atmosphere, and 80 g of the obtained dry powder was put into a mill (Select Grind MJ-518 manufactured by Melita Japan Co., Ltd.) and crushed twice for 20 seconds to disintegrate, It sieved and obtained the silver coating copper powder.

このようにして得られた銀被覆銅粉について、実施例１と同様の方法により、ＢＥＴ比表面積、タップ密度（ＴＡＰ）、銀の被覆量、銀被覆層の厚さ、酸素含有量、炭素含有量、リン含有量および粒度分布を求めるとともに、Ｘ線回折の評価を行った。また、銀被覆前の銅粉について、実施例１と同様の方法により、平均粒径、ＢＥＴ比表面積、酸素含有量およびリン含有量を求めた。 With respect to the silver-coated copper powder thus obtained, the BET specific surface area, tap density (TAP), silver coating amount, silver coating layer thickness, oxygen content, carbon content were measured in the same manner as in Example 1. The amount, phosphorus content and particle size distribution were determined, and the X-ray diffraction was evaluated. The average particle size, BET specific surface area, oxygen content and phosphorus content of the copper powder before silver coating were determined by the same method as in Example 1.

その結果、銀被覆前の銅粉の平均粒径は２．１μｍ、ＢＥＴ比表面積は０．５９ｍ２／ｇ、酸素含有量は０．３６質量％、リン含有量は３２０ｐｐｍであった。また、銀被覆銅粉のＢＥＴ比表面積は０．４５ｍ２／ｇ、タップ密度は５．６ｇ／ｃｍ３、銀の被覆量は２１．６質量％、銀被覆層の厚さは７２ｎｍ、酸素含有量は０．２１質量％、炭素含有量は０．１９質量％、リン含有量は２５０ｐｐｍであった。また、銀被覆銅粉の累積１０％粒子径（Ｄ１０径）は０．８μｍ、累積５０％粒子径（Ｄ５０径）は２．３μｍ、累積９０％粒子径（Ｄ９０径）は４．３μｍであった。また、結晶子径Ｄ（１１１）は１４５ｎｍ、結晶子径Ｄ（２００）は６９ｎｍ、結晶子径Ｄ（２２０）は６８ｎｍであり、Ｄ（１１１）／Ｄ（２００）は２．１０、Ｄ（１１１）／Ｄ（２２０）は２．１３、Ｄ（２００）／Ｄ（２２０）は１．０１であった。 As a result, the average particle diameter of the copper powder before silver coating was 2.1 μm, the BET specific surface area was 0.59 m 2 /g, the oxygen content was 0.36% by mass, and the phosphorus content was 320 ppm. The BET specific surface area of the silver-coated copper powder is 0.45 m 2 /g, the tap density is 5.6 g/cm 3 , the silver coating amount is 21.6% by mass, the silver coating layer has a thickness of 72 nm, and contains oxygen. The amount was 0.21% by mass, the carbon content was 0.19% by mass, and the phosphorus content was 250 ppm. The cumulative 10% particle diameter (D 10 diameter) of the silver-coated copper powder was 0.8 μm, the cumulative 50% particle diameter (D 50 diameter) was 2.3 μm, and the cumulative 90% particle diameter (D 90 diameter) was 4. It was 3 μm. Further, the crystallite diameter D (111) is 145 nm, the crystallite diameter D (200) is 69 nm, the crystallite diameter D (220) is 68 nm, and D (111) /D (200) is 2.10, D ( 111) /D (220) was 2.13 and D (200) /D (220) was 1.01.

また、得られた銀被覆銅粉を使用して、実施例１と同様の方法により、導電性ペーストを作製して導電膜を形成し、得られた導電膜の体積抵抗率の算出と保存安定性（信頼性）の評価を行った。その結果、導電膜の初期の体積抵抗率は３７μΩ・ｃｍ、６週間保存後の体積抵抗率は４７μΩ・ｃｍであり、体積抵抗率の変化率は２７％であった。 Further, using the obtained silver-coated copper powder, a conductive paste was prepared in the same manner as in Example 1 to form a conductive film, and the volume resistivity of the obtained conductive film was calculated and the storage stability was improved. The reliability (reliability) was evaluated. As a result, the initial volume resistivity of the conductive film was 37 μΩ·cm, the volume resistivity after storage for 6 weeks was 47 μΩ·cm, and the change rate of the volume resistivity was 27%.

［実施例４］
高圧水の水圧を１００ＭＰａとした以外は、実施例１と同様の方法により、少量のリンを含む銅粉を得た。 [Example 4]
A copper powder containing a small amount of phosphorus was obtained in the same manner as in Example 1 except that the water pressure of the high pressure water was 100 MPa.

また、ＥＤＴＡ−２Ｎａ二水和物１６７ｇと炭酸アンモニウム１６７ｇを純水１９３９ｇに溶解した溶液（溶液１）と、ＥＤＴＡ−２Ｎａ二水和物３６７ｇと炭酸アンモニウム１８４ｇを純水１４６４ｇに溶解した溶液に、硝酸銀６１ｇを純水１８９ｇに溶解した溶液を加えて得られた溶液（溶液２）を用意した。 Further, a solution (solution 1) prepared by dissolving 167 g of EDTA-2Na dihydrate and 167 g of ammonium carbonate in 1939 g of pure water, and a solution prepared by dissolving 367 g of EDTA-2Na dihydrate and 184 g of ammonium carbonate in 1464 g of pure water, A solution (solution 2) obtained by adding a solution prepared by dissolving 61 g of silver nitrate in 189 g of pure water was prepared.

次に、窒素雰囲気下において、得られた銅粉３５０ｇを溶液１に加えて、攪拌しながら２５℃まで昇温させた。この銅粉が分散した溶液に溶液２を加えて２０分間撹拌することにより、銀により被覆された銅粉を含むスラリーを得た。 Next, in a nitrogen atmosphere, 350 g of the obtained copper powder was added to the solution 1, and the temperature was raised to 25° C. with stirring. Solution 2 was added to the solution in which the copper powder was dispersed and stirred for 20 minutes to obtain a slurry containing the copper powder coated with silver.

次に、得られたスラリーに、表面処理剤としてオレイン酸をアルコールに溶解させて得られた（３質量％のオレイン酸を含む）溶液３５ｇを添加し、４０分間撹拌した後、濾過し、水洗し、真空雰囲気中において７０℃で乾燥し、得られた乾燥粉末８０ｇをミル（メリタジャパン株式会社製のセレクトグラインドＭＪ−５１８）に入れ、２０秒間の粉砕処理を２回行って解砕し、篩別して、銀被覆銅粉末を得た。 Next, 35 g of a solution (containing 3% by mass of oleic acid) obtained by dissolving oleic acid in alcohol as a surface treatment agent was added to the obtained slurry, stirred for 40 minutes, filtered, and washed with water. Then, it was dried at 70° C. in a vacuum atmosphere, and 80 g of the obtained dry powder was put into a mill (Select Grind MJ-518 manufactured by Melita Japan Co., Ltd.) and crushed twice for 20 seconds to disintegrate, It sieved and obtained the silver coating copper powder.

このようにして得られた銀被覆銅粉について、実施例１と同様の方法により、ＢＥＴ比表面積、タップ密度（ＴＡＰ）、銀の被覆量、銀被覆層の厚さ、酸素含有量、炭素含有量、リン含有量および粒度分布を求めるとともに、Ｘ線回折の評価を行った。また、銀被覆前の銅粉について、実施例１と同様の方法により、平均粒径、ＢＥＴ比表面積、酸素含有量およびリン含有量を求めた。 With respect to the silver-coated copper powder thus obtained, the BET specific surface area, tap density (TAP), silver coating amount, silver coating layer thickness, oxygen content, carbon content were measured in the same manner as in Example 1. The amount, phosphorus content and particle size distribution were determined, and the X-ray diffraction was evaluated. The average particle size, BET specific surface area, oxygen content and phosphorus content of the copper powder before silver coating were determined by the same method as in Example 1.

その結果、銀被覆前の銅粉の平均粒径は３．８μｍ、ＢＥＴ比表面積は０．３４ｍ２／ｇ、酸素含有量は０．１９質量％、リン含有量は４７０ｐｐｍであった。また、銀被覆銅粉のＢＥＴ比表面積は０．２２ｍ２／ｇ、タップ密度は６．４ｇ／ｃｍ３、銀の被覆量は１０．０質量％、銀被覆層の厚さは５４ｎｍ、酸素含有量は０．１１質量％、炭素含有量は０．１２質量％、リン含有量は３９０ｐｐｍであった。また、銀被覆銅粉の累積１０％粒子径（Ｄ１０径）は１．３μｍ、累積５０％粒子径（Ｄ５０径）は３．７μｍ、累積９０％粒子径（Ｄ９０径）は７．５μｍであった。また、結晶子径Ｄ（１１１）は１１５ｎｍ、結晶子径Ｄ（２００）は５２ｎｍ、結晶子径Ｄ（２２０）は６０ｎｍであり、Ｄ（１１１）／Ｄ（２００）は２．２１、Ｄ（１１１）／Ｄ（２２０）は１．９２、Ｄ（２００）／Ｄ（２２０）は０．８７であった。 As a result, the average particle diameter of the copper powder before silver coating was 3.8 μm, the BET specific surface area was 0.34 m 2 /g, the oxygen content was 0.19% by mass, and the phosphorus content was 470 ppm. The BET specific surface area of the silver-coated copper powder is 0.22 m 2 /g, the tap density is 6.4 g/cm 3 , the silver coating amount is 10.0 mass %, the silver coating layer thickness is 54 nm, and the oxygen content is The amount was 0.11% by mass, the carbon content was 0.12% by mass, and the phosphorus content was 390 ppm. The cumulative 10% particle diameter (D 10 diameter) of the silver-coated copper powder was 1.3 μm, the cumulative 50% particle diameter (D 50 diameter) was 3.7 μm, and the cumulative 90% particle diameter (D 90 diameter) was 7. It was 5 μm. The crystallite diameter D (111) is 115 nm, the crystallite diameter D (200) is 52 nm, the crystallite diameter D (220) is 60 nm, and D (111) /D (200) is 2.21 and D ( 200). 111) /D (220) was 1.92 and D (200) /D (220) was 0.87.

また、得られた銀被覆銅粉を使用して、実施例１と同様の方法により、導電性ペーストを作製して導電膜を形成し、得られた導電膜の体積抵抗率の算出と保存安定性（信頼性）の評価を行った。その結果、初期の体積抵抗率は３５μΩ・ｃｍ、６週間保存後の体積抵抗率は４６μΩ・ｃｍであり、体積抵抗率の変化率は３１％であった。 Further, using the obtained silver-coated copper powder, a conductive paste was prepared in the same manner as in Example 1 to form a conductive film, and the volume resistivity of the obtained conductive film was calculated and the storage stability was improved. The reliability (reliability) was evaluated. As a result, the initial volume resistivity was 35 μΩ·cm, the volume resistivity after 6 weeks of storage was 46 μΩ·cm, and the rate of change in volume resistivity was 31%.

［実施例５］
銅を加熱して溶解した溶湯中にリン銅合金を添加しなかった以外は、実施例４と同様の方法により、銀被覆銅粉末を得た。 [Example 5]
A silver-coated copper powder was obtained by the same method as in Example 4, except that the copper-phosphorus alloy was not added to the molten metal obtained by heating and melting copper.

このようにして得られた銀被覆銅粉について、実施例１と同様の方法により、ＢＥＴ比表面積、タップ密度（ＴＡＰ）、銀の被覆量、銀被覆層の厚さ、酸素含有量、炭素含有量、リン含有量および粒度分布を求めるとともに、Ｘ線回折の評価を行った。また、銀被覆前の銅粉について、実施例１と同様の方法により、平均粒径、ＢＥＴ比表面積、酸素含有量およびリン含有量を求めた。 With respect to the silver-coated copper powder thus obtained, the BET specific surface area, tap density (TAP), silver coating amount, silver coating layer thickness, oxygen content, carbon content were measured in the same manner as in Example 1. The amount, phosphorus content and particle size distribution were determined, and the X-ray diffraction was evaluated. The average particle size, BET specific surface area, oxygen content and phosphorus content of the copper powder before silver coating were determined by the same method as in Example 1.

その結果、銀被覆前の銅粉の平均粒径は３．７μｍ、ＢＥＴ比表面積は０．２６ｍ２／ｇ、酸素含有量は０．２９質量％、リン含有量は１０ｐｐｍ未満であった。また、銀被覆銅粉のＢＥＴ比表面積は０．２５ｍ２／ｇ、タップ密度は５．５ｇ／ｃｍ３、銀の被覆量は１０．４質量％、銀被覆層の厚さは５６ｎｍ、酸素含有量は０．１４質量％、炭素含有量は０．１３質量％、リン含有量は１０ｐｐｍ未満であった。また、銀被覆銅粉の累積１０％粒子径（Ｄ１０径）は１．４μｍ、累積５０％粒子径（Ｄ５０径）は３．７μｍ、累積９０％粒子径（Ｄ９０径）は６．５μｍであった。また、結晶子径Ｄ（１１１）は１０７ｎｍ、結晶子径Ｄ（２００）は５７ｎｍ、結晶子径Ｄ（２２０）は６０ｎｍであり、Ｄ（１１１）／Ｄ（２００）は１．８８、Ｄ（１１１）／Ｄ（２２０）は１．７８、Ｄ（２００）／Ｄ（２２０）は０．９５であった。 As a result, the average particle diameter of the copper powder before silver coating was 3.7 μm, the BET specific surface area was 0.26 m 2 /g, the oxygen content was 0.29% by mass, and the phosphorus content was less than 10 ppm. In addition, the BET specific surface area of the silver-coated copper powder is 0.25 m 2 /g, the tap density is 5.5 g/cm 3 , the silver coating amount is 10.4% by mass, the thickness of the silver coating layer is 56 nm, and oxygen is contained. The amount was 0.14% by mass, the carbon content was 0.13% by mass, and the phosphorus content was less than 10 ppm. The cumulative 10% particle diameter (D 10 diameter) of the silver-coated copper powder was 1.4 μm, the cumulative 50% particle diameter (D 50 diameter) was 3.7 μm, and the cumulative 90% particle diameter (D 90 diameter) was 6. It was 5 μm. The crystallite diameter D (111) is 107 nm, the crystallite diameter D (200) is 57 nm, the crystallite diameter D (220) is 60 nm, and D (111) /D (200) is 1.88 and D ( 200). 111) /D (220) was 1.78 and D (200) /D (220) was 0.95.

また、得られた銀被覆銅粉を使用して、実施例１と同様の方法により、導電性ペーストを作製して導電膜を形成し、得られた導電膜の体積抵抗率の算出と保存安定性（信頼性）の評価を行った。その結果、導電膜の初期の体積抵抗率は４１μΩ・ｃｍ、６週間保存後の体積抵抗率は７９μΩ・ｃｍであり、体積抵抗率の変化率は９３％であった。 Further, using the obtained silver-coated copper powder, a conductive paste was prepared in the same manner as in Example 1 to form a conductive film, and the volume resistivity of the obtained conductive film was calculated and the storage stability was improved. The reliability (reliability) was evaluated. As a result, the initial volume resistivity of the conductive film was 41 μΩ·cm, the volume resistivity after storage for 6 weeks was 79 μΩ·cm, and the change rate of the volume resistivity was 93%.

［比較例１］
銅を加熱して溶解した溶湯中にリン銅合金を添加せず、高圧水としてｐＨ５．８の水を使用し、窒素ガスの吹き込みを行わなかった以外は、実施例１と同様の方法により、銀被覆銅粉末を得た。 [Comparative Example 1]
By the same method as in Example 1, except that the phosphorus-copper alloy was not added to the molten metal obtained by heating and melting copper, water having a pH of 5.8 was used as high-pressure water, and nitrogen gas was not blown in. A silver-coated copper powder was obtained.

このようにして得られた銀被覆銅粉について、実施例１と同様の方法により、ＢＥＴ比表面積、タップ密度（ＴＡＰ）、銀の被覆量、銀被覆層の厚さ、酸素含有量、炭素含有量、リン含有量および粒度分布を求めるとともに、Ｘ線回折の評価を行った。また、銀被覆前の銅粉について、実施例１と同様の方法により、平均粒径、ＢＥＴ比表面積、酸素含有量およびリン含有量を求めた。 With respect to the silver-coated copper powder thus obtained, the BET specific surface area, tap density (TAP), silver coating amount, silver coating layer thickness, oxygen content, carbon content were measured in the same manner as in Example 1. The amount, phosphorus content and particle size distribution were determined, and the X-ray diffraction was evaluated. The average particle diameter, BET specific surface area, oxygen content and phosphorus content of the copper powder before silver coating were determined by the same method as in Example 1.

その結果、銀被覆前の銅粉の平均粒径は２．３μｍ、ＢＥＴ比表面積は０．６０ｍ２／ｇ、酸素含有量は０．２２質量％、リン含有量は１０ｐｐｍ未満であった。また、銀被覆銅粉のＢＥＴ比表面積は０．４５ｍ２／ｇ、タップ密度は５．８ｇ／ｃｍ３、銀の被覆量は１０．６質量％、銀被覆層の厚さは３５ｎｍ、酸素含有量は０．２２質量％、炭素含有量は０．１８質量％、リン含有量は１０ｐｐｍ未満であった。また、銀被覆銅粉の累積１０％粒子径（Ｄ１０径）は０．９μｍ、累積５０％粒子径（Ｄ５０径）は２．３μｍ、累積９０％粒子径（Ｄ９０径）は３．９μｍであった。また、結晶子径Ｄ（１１１）は１１３ｎｍ、結晶子径Ｄ（２００）は６６ｎｍ、結晶子径Ｄ（２２０）は６０ｎｍであり、Ｄ（１１１）／Ｄ（２００）は１．７１、Ｄ（１１１）／Ｄ（２２０）は１．８８、Ｄ（２００）／Ｄ（２２０）は１．１０であった。 As a result, the average particle diameter of the copper powder before silver coating was 2.3 μm, the BET specific surface area was 0.60 m 2 /g, the oxygen content was 0.22% by mass, and the phosphorus content was less than 10 ppm. The BET specific surface area of the silver-coated copper powder is 0.45 m 2 /g, the tap density is 5.8 g/cm 3 , the silver coating amount is 10.6% by mass, the silver coating layer thickness is 35 nm, and the oxygen content is The amount was 0.22% by mass, the carbon content was 0.18% by mass, and the phosphorus content was less than 10 ppm. The cumulative 10% particle diameter (D 10 diameter) of the silver-coated copper powder was 0.9 μm, the cumulative 50% particle diameter (D 50 diameter) was 2.3 μm, and the cumulative 90% particle diameter (D 90 diameter) was 3. It was 9 μm. The crystallite diameter D (111) is 113 nm, the crystallite diameter D (200) is 66 nm, the crystallite diameter D (220) is 60 nm, and D (111) /D (200) is 1.71 and D ( 200). 111) /D (220) was 1.88 and D (200) /D (220) was 1.10.

また、得られた銀被覆銅粉を使用して、実施例１と同様の方法により、導電性ペーストを作製して導電膜を形成し、得られた導電膜の体積抵抗率の算出と保存安定性（信頼性）の評価を行った。その結果、初期の体積抵抗率は４７μΩ・ｃｍ、６週間保存後の体積抵抗率は１３１μΩ・ｃｍであり、体積抵抗率の変化率は１７８％であった。 Further, using the obtained silver-coated copper powder, a conductive paste was prepared in the same manner as in Example 1 to form a conductive film, and the volume resistivity of the obtained conductive film was calculated and the storage stability was improved. The reliability (reliability) was evaluated. As a result, the initial volume resistivity was 47 μΩ·cm, the volume resistivity after storage for 6 weeks was 131 μΩ·cm, and the rate of change in volume resistivity was 178%.

［比較例２］
銅を加熱して溶解した溶湯中にリン銅合金を添加せず、窒素ガスの吹き込みを行わなかった以外は、実施例１と同様の方法により、銀被覆銅粉末を得た。 [Comparative example 2]
A silver-coated copper powder was obtained by the same method as in Example 1 except that the copper-phosphorus alloy was not added to the molten metal obtained by heating and melting copper, and that nitrogen gas was not blown.

このようにして得られた銀被覆銅粉について、実施例１と同様の方法により、ＢＥＴ比表面積、タップ密度（ＴＡＰ）、銀の被覆量、銀被覆層の厚さ、酸素含有量、炭素含有量、リン含有量および粒度分布を求めるとともに、Ｘ線回折の評価を行った。また、銀被覆前の銅粉について、実施例１と同様の方法により、平均粒径、ＢＥＴ比表面積、酸素含有量およびリン含有量を求めた。 With respect to the silver-coated copper powder thus obtained, the BET specific surface area, tap density (TAP), silver coating amount, silver coating layer thickness, oxygen content, carbon content were measured in the same manner as in Example 1. The amount, phosphorus content and particle size distribution were determined, and the X-ray diffraction was evaluated. The average particle size, BET specific surface area, oxygen content and phosphorus content of the copper powder before silver coating were determined by the same method as in Example 1.

その結果、銀被覆前の銅粉の平均粒径は２．１μｍ、ＢＥＴ比表面積は０．６１ｍ２／ｇ、酸素含有量は０．２１質量％、リン含有量は１０ｐｐｍ未満であった。また、銀被覆銅粉のＢＥＴ比表面積は０．４５ｍ２／ｇ、タップ密度は５．７ｇ／ｃｍ３、銀の被覆量は１０．５質量％、銀被覆層の厚さは３１ｎｍ、酸素含有量は０．２１質量％、炭素含有量は０．１５質量％、リン含有量は１０ｐｐｍ未満であった。また、銀被覆銅粉の累積１０％粒子径（Ｄ１０径）は０．８μｍ、累積５０％粒子径（Ｄ５０径）は２．１μｍ、累積９０％粒子径（Ｄ９０径）は３．８μｍであった。また、結晶子径Ｄ（１１１）は１０６ｎｍ、結晶子径Ｄ（２００）は６９ｎｍ、結晶子径Ｄ（２２０）は６１ｎｍであり、Ｄ（１１１）／Ｄ（２００）は１．５４、Ｄ（１１１）／Ｄ（２２０）は１．７４、Ｄ（２００）／Ｄ（２２０）は１．１３であった。 As a result, the average particle diameter of the copper powder before silver coating was 2.1 μm, the BET specific surface area was 0.61 m 2 /g, the oxygen content was 0.21% by mass, and the phosphorus content was less than 10 ppm. Further, the BET specific surface area of the silver-coated copper powder is 0.45 m 2 /g, the tap density is 5.7 g/cm 3 , the silver coating amount is 10.5% by mass, the silver coating layer has a thickness of 31 nm, and contains oxygen. The amount was 0.21% by mass, the carbon content was 0.15% by mass, and the phosphorus content was less than 10 ppm. The cumulative 10% particle diameter (D 10 diameter) of the silver-coated copper powder was 0.8 μm, the cumulative 50% particle diameter (D 50 diameter) was 2.1 μm, and the cumulative 90% particle diameter (D 90 diameter) was 3. It was 8 μm. Further, the crystallite diameter D (111) is 106 nm, the crystallite diameter D (200) is 69 nm, the crystallite diameter D (220) is 61 nm, and D (111) /D (200) is 1.54, D ( 111) /D (220) was 1.74 and D (200) /D (220) was 1.13.

また、得られた銀被覆銅粉を使用して、実施例１と同様の方法により、導電性ペーストを作製して導電膜を形成し、得られた導電膜の体積抵抗率の算出と保存安定性（信頼性）の評価を行った。その結果、導電膜の初期の体積抵抗率は４８μΩ・ｃｍ、６週間保存後の体積抵抗率は１５８μΩ・ｃｍであり、体積抵抗率の変化率は２２９％であった。 Further, using the obtained silver-coated copper powder, a conductive paste was prepared in the same manner as in Example 1 to form a conductive film, and the volume resistivity of the obtained conductive film was calculated and the storage stability was improved. The reliability (reliability) was evaluated. As a result, the initial volume resistivity of the conductive film was 48 μΩ·cm, the volume resistivity after storage for 6 weeks was 158 μΩ·cm, and the change rate of the volume resistivity was 229%.

これらの実施例および比較例の銀被覆銅粉の製造条件および特性を表１〜表３に示す。 Tables 1 to 3 show the production conditions and characteristics of the silver-coated copper powders of these Examples and Comparative Examples.

Figure 0006722495
Figure 0006722495

Figure 0006722495
Figure 0006722495

Figure 0006722495
Figure 0006722495

これらの表からわかるように、実施例の銀被覆銅粉を使用して作製した導電膜は、比較例の銀被覆銅粉を使用して作製した導電膜と比べて、初期の体積抵抗率が低く、１５０℃で６週間保存した後の体積抵抗率の変化率（％）が低くなり、導電膜の保存安定性（信頼性）に優れている。 As can be seen from these tables, the conductive film prepared using the silver-coated copper powder of the example has an initial volume resistivity higher than that of the conductive film prepared using the silver-coated copper powder of the comparative example. The change rate (%) of the volume resistivity after storage at 150° C. for 6 weeks is low, and the storage stability (reliability) of the conductive film is excellent.

また、実施例および比較例の銀被覆銅粉のＣｕの（２００）面における結晶子径Ｄ（２００）に対するＣｕの（１１１）面における結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２００）と、その銀被覆銅粉を使用して作製した導電膜を１５０℃で６週間保存した後の体積抵抗率の変化率（％）との関係を図１に示し、実施例および比較例の銀被覆銅粉のＣｕの（２２０）面における結晶子径Ｄ（２２０）に対するＣｕの（２００）面における結晶子径Ｄ（２００）の比Ｄ（２００）／Ｄ（２２０）と、その銀被覆銅粉を使用して作製した導電膜を１５０℃で６週間保存した後の体積抵抗率の変化率（％）との関係を図２に示す。また、実施例および比較例の銀被覆銅粉の銀被覆層の厚さと、その銀被覆銅粉を使用して作製した導電膜を１５０℃で６週間保存した後の体積抵抗率の変化率（％）との関係を図３に示す。 Further, the ratio D (111) /D of the crystallite diameter D (111) on the (111) plane of Cu to the crystallite diameter D (200) on the Cu (200) plane of the silver-coated copper powders of Examples and Comparative Examples. The relationship between (200) and the rate of change (%) in volume resistivity after storing a conductive film prepared using the silver-coated copper powder at 150° C. for 6 weeks is shown in FIG. The ratio D (200) /D (220) of the crystallite diameter D (200) on the (200) plane of Cu to the crystallite diameter D (220) on the Cu (220) plane of the silver-coated copper powder of the example, and FIG. 2 shows the relationship with the rate of change (%) in volume resistivity after the conductive film produced using the silver-coated copper powder was stored at 150° C. for 6 weeks. In addition, the thickness of the silver coating layer of the silver-coated copper powders of Examples and Comparative Examples and the rate of change of the volume resistivity after storing the conductive film produced using the silver-coated copper powder at 150° C. for 6 weeks ( %) is shown in FIG.

図１からわかるように、Ｃｕの（２００）面における結晶子径Ｄ（２００）に対するＣｕの（１１１）面における結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２００）が１．８以上の銀被覆銅粉（実施例の銀被覆銅粉）は、その比が１．８より低い比較例の銀被覆銅粉と比べて、作製した導電膜を１５０℃で６週間保存した後の体積抵抗率の変化率（％）が低くなり、導電膜の保存安定性（信頼性）に優れている。また、図２からわかるように、Ｃｕの（２２０）面における結晶子径Ｄ（２２０）に対するＣｕの（２００）面における結晶子径Ｄ（２００）の比Ｄ（２００）／Ｄ（２２０）が１．１より低い銀被覆銅粉（実施例の銀被覆銅粉）は、その比が１．１以上の比較例の銀被覆銅粉と比べて、作製した導電膜を１５０℃で６週間保存した後の体積抵抗率の変化率（％）が低くなり、導電膜の保存安定性（信頼性）に優れている。さらに、図３からわかるように、実施例の銀被覆銅粉を使用して作製した導電膜は、比較例の銀被覆銅粉を使用して作製した導電膜と比べて、同じ銀被覆層の厚さでも、導電膜を１５０℃で６週間保存した後の体積抵抗率の変化率（％）が大幅に低くなり、導電膜の保存安定性（信頼性）を大幅に向上させることができる。 As can be seen from FIG. 1, the ratio D (111) /D (200) of the crystallite diameter D (111) of the Cu (111) plane to the crystallite diameter D (200) of the Cu (200 ) plane is 1. After the silver-coated copper powder having a ratio of 8 or more (the silver-coated copper powder of the example) was stored at 150° C. for 6 weeks, the prepared conductive film was compared with the silver-coated copper powder of the comparative example whose ratio was lower than 1.8. The volume resistivity change rate (%) is low, and the conductive film is excellent in storage stability (reliability). Further, as can be seen from FIG. 2, the ratio D (200) /D (220) of the crystallite diameter D (200) of the Cu (200) plane to the crystallite diameter D (220) of the Cu (220 ) plane is The silver-coated copper powder having a ratio lower than 1.1 (the silver-coated copper powder of the example) has a ratio of 1.1 or more, and the prepared conductive film is stored at 150° C. for 6 weeks as compared with the silver-coated copper powder of the comparative example. The change rate (%) of the volume resistivity after the treatment is low, and the storage stability (reliability) of the conductive film is excellent. Further, as can be seen from FIG. 3, the conductive film produced using the silver-coated copper powder of the example has the same silver coating layer as the conductive film produced using the silver-coated copper powder of the comparative example. Even with the thickness, the change rate (%) of the volume resistivity after the conductive film is stored at 150° C. for 6 weeks is significantly reduced, and the storage stability (reliability) of the conductive film can be significantly improved.

本発明による銀被覆銅粉は、回路基板の導体パターン、太陽電池などの基板の電極や回路などの電子部品に使用する導電性ペーストの作製に利用することができる。 INDUSTRIAL APPLICABILITY The silver-coated copper powder according to the present invention can be used for producing a conductive pattern used for a conductor pattern of a circuit board, an electrode of a substrate such as a solar cell, or an electronic component such as a circuit.

Claims (10)

銅を加熱して溶解した溶湯を落下させながら高圧水を吹き付けて急冷凝固して得られた銅粉のスラリーを非酸化性ガスの存在下で保持した後、固液分離して得られた銅粉を銀含有層で被覆することを特徴とする、銀被覆銅粉の製造方法。 Copper obtained by solid-liquid separation after holding a slurry of copper powder obtained by rapidly solidifying by cooling with high-pressure water while heating molten copper and dropping molten metal in the presence of non-oxidizing gas A method for producing a silver-coated copper powder, which comprises coating the powder with a silver-containing layer. 前記スラリー中と前記スラリーを収容する容器内との少なくとも一方に前記非酸化性ガスを吹き込みながら保持することによって、前記スラリーを非酸化性ガスの存在下で保持することを特徴とする、請求項１に記載の銀被覆銅粉の製造方法。 By holding the non-oxidizing gas while blowing the non-oxidizing gas into at least one of the slurry and a container that contains the slurry, the slurry is held in the presence of the non-oxidizing gas, 1. The method for producing the silver-coated copper powder according to 1. 前記銅粉のレーザー回折式粒度分布装置により測定した体積基準の累積５０％粒子径（Ｄ５０径）が０．１〜１５μｍであることを特徴とする、請求項１または２に記載の銀被覆銅粉の製造方法。 The volume-based cumulative 50% particle size (D 50 size) of the copper powder measured by a laser diffraction particle size distribution device is 0.1 to 15 μm, and the silver coating according to claim 1 or 2. Method for producing copper powder. 前記高圧水がアルカリ水溶液であることを特徴とする、請求項１乃至３のいずれかに記載の銀被覆銅粉の製造方法。 The method for producing silver-coated copper powder according to claim 1, wherein the high-pressure water is an alkaline aqueous solution. 前記溶湯にリンを添加することを特徴とする、請求項１乃至４のいずれかに記載の銀被覆銅粉の製造方法。 The method for producing silver-coated copper powder according to claim 1, wherein phosphorus is added to the molten metal. 銅粉の表面が銀含有層で被覆された銀被覆銅粉であって、Ｃｕの（２００）面における結晶子径Ｄ（２００）に対するＣｕの（１１１）面における結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２００）が１．８以上２．２１以下であり且つＣｕの（２２０）面における結晶子径Ｄ（２２０）に対するＣｕの（２００）面における結晶子径Ｄ（２００）の比Ｄ（２００）／Ｄ（２２０）が０．８７以上１．０９５以下であることを特徴とする、銀被覆銅粉。
A silver-coated copper powder whose surface is coated with a silver-containing layer of the copper powder, the Cu (200) crystallite diameter D (200) for the Cu in the surface of the (111) crystallite in surface diameter D (111) the ratio D (111) / D (200) is 1.8 or more 2.21 or less and and crystallite size in the (200) plane of Cu with respect to (220) crystallite diameter D (220) in the surface of the Cu D (200 ) Ratio D (200) /D (220) of 0.87 or more and 1.095 or less, silver-coated copper powder.
前記銀被覆銅粉のＣｕの（２２０）面における結晶子径Ｄ（２２０）に対するＣｕの（１１１）面における結晶子径Ｄ（１１１）の比Ｄ（１１１）／Ｄ（２２０）が１．９０以上であることを特徴とする、請求項６に記載の銀被覆銅粉。 The ratio D (111) /D (220) of the crystallite diameter D (111) of the (111) plane of Cu to the crystallite diameter D (220) of the (220) plane of Cu of the silver-coated copper powder is 1.90. It is above, The silver coating copper powder of Claim 6 characterized by the above-mentioned. 前記銀被覆銅粉のレーザー回折式粒度分布装置により測定した体積基準の累積５０％粒子径（Ｄ５０径）が０．１〜１５μｍであることを特徴とする、請求項６または７に記載の銀被覆銅粉。 8. The volume-based cumulative 50% particle size (D50 size) of the silver-coated copper powder measured by a laser diffraction particle size distribution device is 0.1 to 15 μm, according to claim 6 or 7. Silver-coated copper powder. 前記銀被覆銅粉中のリン含有量が１０〜１０００ｐｐｍであることを特徴とする、請求項６乃至８のいずれかに記載の銀被覆銅粉。 The silver-coated copper powder according to any one of claims 6 to 8, characterized in that a phosphorus content in the silver-coated copper powder is 10 to 1000 ppm. 導電性粉末として請求項６乃至９のいずれかに記載の銀被覆銅粉を含むことを特徴とする、導電性ペースト。 A conductive paste comprising the silver-coated copper powder according to any one of claims 6 to 9 as the conductive powder.
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