JP5439057B2 - Composite copper particles - Google Patents
Composite copper particles Download PDFInfo
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- JP5439057B2 JP5439057B2 JP2009154400A JP2009154400A JP5439057B2 JP 5439057 B2 JP5439057 B2 JP 5439057B2 JP 2009154400 A JP2009154400 A JP 2009154400A JP 2009154400 A JP2009154400 A JP 2009154400A JP 5439057 B2 JP5439057 B2 JP 5439057B2
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- particles
- inorganic oxide
- copper
- mother
- oxide particles
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- 239000002245 particle Substances 0.000 title claims description 539
- 239000010949 copper Substances 0.000 title claims description 206
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims description 149
- 229910052802 copper Inorganic materials 0.000 title claims description 144
- 239000002131 composite material Substances 0.000 title claims description 108
- 229910052809 inorganic oxide Inorganic materials 0.000 claims description 125
- 239000007788 liquid Substances 0.000 claims description 40
- 239000003638 chemical reducing agent Substances 0.000 claims description 27
- 230000009467 reduction Effects 0.000 claims description 21
- 238000004519 manufacturing process Methods 0.000 claims description 14
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 claims description 8
- 229910001431 copper ion Inorganic materials 0.000 claims description 8
- 229910000431 copper oxide Inorganic materials 0.000 claims description 8
- 239000002923 metal particle Substances 0.000 claims description 8
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims description 5
- 239000005751 Copper oxide Substances 0.000 claims description 5
- JJLJMEJHUUYSSY-UHFFFAOYSA-L Copper hydroxide Chemical compound [OH-].[OH-].[Cu+2] JJLJMEJHUUYSSY-UHFFFAOYSA-L 0.000 claims description 4
- 239000005750 Copper hydroxide Substances 0.000 claims description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 4
- 229910001956 copper hydroxide Inorganic materials 0.000 claims description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 2
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 2
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 92
- 238000000034 method Methods 0.000 description 47
- 238000006722 reduction reaction Methods 0.000 description 30
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 24
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 24
- IKDUDTNKRLTJSI-UHFFFAOYSA-N hydrazine hydrate Chemical compound O.NN IKDUDTNKRLTJSI-UHFFFAOYSA-N 0.000 description 24
- 239000000243 solution Substances 0.000 description 24
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 22
- 239000007864 aqueous solution Substances 0.000 description 20
- 229910010413 TiO 2 Inorganic materials 0.000 description 18
- 239000007771 core particle Substances 0.000 description 15
- 239000002002 slurry Substances 0.000 description 14
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 13
- 229910000365 copper sulfate Inorganic materials 0.000 description 11
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 11
- 238000005245 sintering Methods 0.000 description 11
- BERDEBHAJNAUOM-UHFFFAOYSA-N copper(I) oxide Inorganic materials [Cu]O[Cu] BERDEBHAJNAUOM-UHFFFAOYSA-N 0.000 description 10
- KRFJLUBVMFXRPN-UHFFFAOYSA-N cuprous oxide Chemical compound [O-2].[Cu+].[Cu+] KRFJLUBVMFXRPN-UHFFFAOYSA-N 0.000 description 10
- 229940112669 cuprous oxide Drugs 0.000 description 10
- 238000005259 measurement Methods 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 230000007423 decrease Effects 0.000 description 8
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 7
- 235000011114 ammonium hydroxide Nutrition 0.000 description 7
- 230000004927 fusion Effects 0.000 description 7
- 239000000843 powder Substances 0.000 description 7
- 238000003756 stirring Methods 0.000 description 7
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 6
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 6
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- 239000002585 base Substances 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 238000004090 dissolution Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000001914 filtration Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 238000005406 washing Methods 0.000 description 5
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 4
- 239000011231 conductive filler Substances 0.000 description 4
- POULHZVOKOAJMA-UHFFFAOYSA-N dodecanoic acid Chemical compound CCCCCCCCCCCC(O)=O POULHZVOKOAJMA-UHFFFAOYSA-N 0.000 description 4
- 238000010304 firing Methods 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 239000011259 mixed solution Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000003513 alkali Substances 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 239000003985 ceramic capacitor Substances 0.000 description 3
- 230000008602 contraction Effects 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- -1 for example Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 238000010348 incorporation Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000003002 pH adjusting agent Substances 0.000 description 3
- 239000011164 primary particle Substances 0.000 description 3
- 239000012756 surface treatment agent Substances 0.000 description 3
- 238000009210 therapy by ultrasound Methods 0.000 description 3
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 description 2
- IVORCBKUUYGUOL-UHFFFAOYSA-N 1-ethynyl-2,4-dimethoxybenzene Chemical compound COC1=CC=C(C#C)C(OC)=C1 IVORCBKUUYGUOL-UHFFFAOYSA-N 0.000 description 2
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 description 2
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 description 2
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 2
- 239000004471 Glycine Substances 0.000 description 2
- 239000005639 Lauric acid Substances 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 239000005642 Oleic acid Substances 0.000 description 2
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 description 2
- 235000021355 Stearic acid Nutrition 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000008103 glucose Substances 0.000 description 2
- 230000003301 hydrolyzing effect Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 2
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 2
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid Chemical compound CCCCCCCC\C=C/CCCCCCCC(O)=O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000011946 reduction process Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000008117 stearic acid Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- GYSCBCSGKXNZRH-UHFFFAOYSA-N 1-benzothiophene-2-carboxamide Chemical compound C1=CC=C2SC(C(=O)N)=CC2=C1 GYSCBCSGKXNZRH-UHFFFAOYSA-N 0.000 description 1
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical group C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 1
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 1
- 150000000703 Cerium Chemical class 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- GHVNFZFCNZKVNT-UHFFFAOYSA-N Decanoic acid Natural products CCCCCCCCCC(O)=O GHVNFZFCNZKVNT-UHFFFAOYSA-N 0.000 description 1
- 229920000084 Gum arabic Polymers 0.000 description 1
- 241000978776 Senegalia senegal Species 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- FZQSLXQPHPOTHG-UHFFFAOYSA-N [K+].[K+].O1B([O-])OB2OB([O-])OB1O2 Chemical compound [K+].[K+].O1B([O-])OB2OB([O-])OB1O2 FZQSLXQPHPOTHG-UHFFFAOYSA-N 0.000 description 1
- 239000000205 acacia gum Substances 0.000 description 1
- 235000010489 acacia gum Nutrition 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000001099 ammonium carbonate Substances 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- RJTANRZEWTUVMA-UHFFFAOYSA-N boron;n-methylmethanamine Chemical compound [B].CNC RJTANRZEWTUVMA-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- UNJPQTDTZAKTFK-UHFFFAOYSA-K cerium(iii) hydroxide Chemical compound [OH-].[OH-].[OH-].[Ce+3] UNJPQTDTZAKTFK-UHFFFAOYSA-K 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- OPQARKPSCNTWTJ-UHFFFAOYSA-L copper(ii) acetate Chemical compound [Cu+2].CC([O-])=O.CC([O-])=O OPQARKPSCNTWTJ-UHFFFAOYSA-L 0.000 description 1
- AEJIMXVJZFYIHN-UHFFFAOYSA-N copper;dihydrate Chemical compound O.O.[Cu] AEJIMXVJZFYIHN-UHFFFAOYSA-N 0.000 description 1
- 238000002242 deionisation method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000002431 foraging effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000010954 inorganic particle Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000000615 nonconductor Substances 0.000 description 1
- 229910052755 nonmetal Inorganic materials 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 150000003018 phosphorus compounds Chemical class 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000005049 silicon tetrachloride Substances 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000000527 sonication Methods 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 150000003608 titanium Chemical class 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 229910000406 trisodium phosphate Inorganic materials 0.000 description 1
- 235000019801 trisodium phosphate Nutrition 0.000 description 1
- 238000000108 ultra-filtration Methods 0.000 description 1
- 150000003754 zirconium Chemical class 0.000 description 1
- 150000003755 zirconium compounds Chemical class 0.000 description 1
Classifications
-
- 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
- B22F9/16—Making metallic powder or suspensions thereof using chemical processes
- B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
- B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B6/00—Hydrides of metals including fully or partially hydrided metals, alloys or intermetallic compounds ; Compounds containing at least one metal-hydrogen bond, e.g. (GeH3)2S, SiH GeH; Monoborane or diborane; Addition complexes thereof
- C01B6/04—Hydrides of alkali metals, alkaline earth metals, beryllium or magnesium; Addition complexes thereof
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Powder Metallurgy (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
Description
本発明は、銅を含む母粒子中に複数の無機酸化物粒子が含有されてなる複合銅粒子に関する。 The present invention relates to composite copper particles in which a plurality of inorganic oxide particles are contained in mother particles containing copper.
導電ペーストは、樹脂系バインダと溶媒からなるビヒクル中に、導電フィラーを分散させた流動性組成物であり、電気回路の形成や、セラミックコンデンサの外部電極の形成などに広く用いられている。 The conductive paste is a fluid composition in which a conductive filler is dispersed in a vehicle composed of a resin binder and a solvent, and is widely used for forming an electric circuit, an external electrode of a ceramic capacitor, and the like.
かかる導電ペーストの一種として、高温焼成によって有機成分が揮発し導電フィラーが焼結して導通を確保する高温焼成型導電ペーストがある。 One type of such conductive paste is a high-temperature fired conductive paste in which organic components are volatilized by high-temperature firing and conductive fillers are sintered to ensure conduction.
この高温焼成型導電ペーストは、一般に金属粒子に代表される導電フィラーとガラスフリットとを、有機ビヒクル中に分散させてなるペースト状組成物であり、４００〜８００℃程度の比較的高温で焼成することによって、有機ビヒクルが揮発し、更に導電フィラーが焼結することによって導通が確保されるものである。この際、ガラスフリットは、この導電膜を基板に接着させる作用を有し、有機ビヒクルは、金属粉末及びガラスフリットを印刷可能にするための有機液体媒体として作用する。高温焼成型導電ペーストは、焼成温度が高いため、プリント配線基板や樹脂材料には使用できないが、焼結して金属が一体化することから低抵抗化を実現することができ、例えば積層セラミックコンデンサの外部電極などに使用されている。 This high-temperature firing type conductive paste is a paste-like composition in which conductive fillers typically represented by metal particles and glass frit are dispersed in an organic vehicle, and is fired at a relatively high temperature of about 400 to 800 ° C. As a result, the organic vehicle is volatilized and the conductive filler is sintered to ensure conduction. At this time, the glass frit has a function of adhering the conductive film to the substrate, and the organic vehicle functions as an organic liquid medium for enabling printing of the metal powder and the glass frit. High-temperature fired conductive paste cannot be used for printed wiring boards or resin materials because of its high firing temperature, but it can achieve low resistance because it is sintered and the metal is integrated. For example, multilayer ceramic capacitors It is used for external electrodes.
ところで、導電ペーストに用いられる金属粒子として、母材となる金属粒子と無機酸化物とを複合化させた粒子が種々提案されている。例えば特許文献１及び２には、銅の粒子の表面にＳｉＯ2を被覆してなる銅粒子が記載されている。これらの文献には、この銅粒子からなる銅粉を含む導電ペーストは、耐酸化性と焼結性に優れたものであると記載されている。しかし、焼結時における耐熱収縮性の改善については検討されていない。 By the way, as metal particles used in the conductive paste, various particles in which metal particles serving as a base material and an inorganic oxide are combined have been proposed. For example, Patent Documents 1 and 2 describe copper particles obtained by coating the surface of copper particles with SiO 2 . In these documents, it is described that the conductive paste containing the copper powder made of the copper particles is excellent in oxidation resistance and sinterability. However, improvement of heat shrinkage resistance during sintering has not been studied.
前記の技術とは別に、本出願人は、金属粉の耐熱収縮性を高め、寸法安定性に優れた導電回路を得ることを目的として、金属粉の粉粒表面に無機酸化物層を形成してなる無機酸化物コート金属粉を提案した（特許文献３参照）。無機酸化物層は、酸化ケイ素や酸化アルミニウムから構成されている。金属粉は、銅粉や銀粉である。無機酸化物層は、金属粉の粉粒の表面に、無機酸化物をメカノケミカル的な手法で固着させることで形成されている。 Apart from the above technique, the present applicant formed an inorganic oxide layer on the surface of the metal powder particles for the purpose of improving the heat shrinkability of the metal powder and obtaining a conductive circuit with excellent dimensional stability. An inorganic oxide-coated metal powder was proposed (see Patent Document 3). The inorganic oxide layer is composed of silicon oxide or aluminum oxide. The metal powder is copper powder or silver powder. The inorganic oxide layer is formed by fixing the inorganic oxide on the surface of the metal powder particles by a mechanochemical method.
しかし、導電ペースト用、殊に高温焼成型導電ペースト用の金属粒子に要求される特性はますます厳しくなっており、耐熱収縮性についても、一層の向上が求められている。 However, the characteristics required for metal particles for conductive pastes, particularly high-temperature fired conductive pastes, are becoming more and more severe, and further improvement in heat shrinkability is required.
本発明の目的は、前述した従来技術の粒子よりも各種の性能が一層向上した複合金属粒子を提供することにある。 An object of the present invention is to provide composite metal particles having various performances further improved as compared with the above-described prior art particles.
本発明は、平均粒径が０．２〜１０μｍである銅を含む母粒子中に、平均粒径が５〜５０ｎｍである無機酸化物粒子が複数含まれている複合銅粒子であって、
無機酸化物粒子は、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとからなり、
無機酸化物粒子が複合銅粒子全体に対して０．１〜５重量％含有されていることを特徴とする複合銅粒子を提供するものである。
The present invention is a composite copper particle in which a plurality of inorganic oxide particles having an average particle diameter of 5 to 50 nm are contained in a mother particle containing copper having an average particle diameter of 0.2 to 10 μm,
The inorganic oxide particles consist of those that are completely embedded in the vicinity of the surface of the mother particles and those that are embedded in the mother particles in a partially exposed state on the surface of the mother particles.
The present invention provides composite copper particles characterized in that the inorganic oxide particles are contained in an amount of 0.1 to 5% by weight based on the entire composite copper particles.
また本発明は、前記の複合銅粒子の製造方法であって、
銅イオン若しくは銅を含むイオン種、銅酸化物又は銅水酸化物及び無機酸化物粒子を含む水性液に還元剤を添加して、銅の還元を行う工程を有し、
銅の還元中に、無機酸化物粒子を、当初水性液中に存在するものとは別に添加するか、又は
銅の還元中の液のｐＨを７．５〜１２の範囲に調整する
ことを特徴とする複合金属粒子の製造方法を提供するものである。
The present invention is also a method for producing the composite copper particles,
A step of reducing copper by adding a reducing agent to an aqueous liquid containing copper ions or copper-containing ionic species, copper oxide or copper hydroxide and inorganic oxide particles,
During the reduction of copper, the inorganic oxide particles are added separately from those originally present in the aqueous liquid, or the pH of the liquid during the reduction of copper is adjusted to a range of 7.5 to 12. A method for producing composite metal particles is provided.
本発明の複合銅粒子は、高温焼成型導電ペーストとして用いられる際の熱収縮性のコントロールが容易なものである。 The composite copper particles of the present invention can be easily controlled in heat shrinkability when used as a high-temperature fired conductive paste.
以下本発明を、その好ましい実施形態に基づき説明する。本発明の複合銅粒子は、銅からなる母粒子と、無機酸化物粒子との複合体から構成されている。無機酸化物粒子は、母粒子よりも粒径の小さいものである。無機酸化物粒子は、１個の母粒子中に複数個含まれている。複合銅粒子は、母粒子中における無機酸化物粒子の存在位置に特徴の一つを有している。詳細には、無機酸化物粒子は、（イ）母粒子の表面近傍に完全包埋されているものと、（ロ）母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとの少なくとも２種類からなる。無機酸化物粒子がこのような位置に存在していることによって、例えば複合銅粒子を含むペースト等からなる導体を焼結するときに、複合銅粒子の熱収縮開始温度及び熱収縮速度をコントロールすることが可能となる。その理由は以下のとおりである。 Hereinafter, the present invention will be described based on preferred embodiments thereof. The composite copper particles of the present invention are composed of a composite of mother particles made of copper and inorganic oxide particles. The inorganic oxide particles have a smaller particle size than the mother particles. A plurality of inorganic oxide particles are contained in one base particle. The composite copper particles have one of the characteristics in the location of the inorganic oxide particles in the mother particles. Specifically, the inorganic oxide particles are either (a) completely embedded in the vicinity of the surface of the mother particle or (b) embedded in the mother particle while being partially exposed on the surface of the mother particle. It consists of at least two types. Due to the presence of the inorganic oxide particles in such a position, for example, when a conductor made of a paste containing composite copper particles is sintered, the thermal shrinkage start temperature and the heat shrinkage rate of the composite copper particles are controlled. It becomes possible. The reason is as follows.
（ロ）の無機酸化物粒子が存在することで、焼結時に複合銅粒子どうしの融着が阻害され、熱収縮開始温度が高くなる。熱収縮速度に関しては、一般に銅の融着が開始されると熱収縮速度が一気に高まるところ、本発明においては（イ）の無機酸化物粒子の存在によって、焼結収縮が一気に進行することが阻害される。それによって、熱収縮速度が抑制される。これらの理由によって、本発明の複合銅粒子によれば、焼結時の熱収縮のコントロールを容易に行うことができる。先に述べた特許文献１及び２に記載の技術では、銅粒子の表面にのみＳｉＯ2が存在している状態なので、融着が始まると熱収縮を妨害するものがないために一気に熱収縮が進行してしまう。この現象は、粒子を電極の形成に使用したときに、クラックや剥がれの原因となる。また特許文献３に記載の技術では、特許文献１及び２と同様に融着が始まると一気に熱収縮してしまう場合がある。また粒子の塗膜を形成した後に熱処理して粒子を高結晶化させないと、十分な耐熱収縮効果が得られないことがある。 Due to the presence of the inorganic oxide particles (b), the fusion of the composite copper particles is inhibited during sintering, and the thermal shrinkage start temperature is increased. Regarding the heat shrinkage rate, when the copper fusion is generally started, the heat shrinkage rate increases at a stretch. In the present invention, the presence of the inorganic oxide particles (a) prevents the sintering shrinkage from proceeding at a stretch. Is done. Thereby, the heat shrinkage rate is suppressed. For these reasons, according to the composite copper particles of the present invention, it is possible to easily control heat shrinkage during sintering. In the techniques described in Patent Documents 1 and 2 described above, since SiO 2 exists only on the surface of the copper particles, there is nothing that disturbs heat shrinkage when fusion starts, so heat shrinkage occurs at once. It will progress. This phenomenon causes cracks and peeling when the particles are used to form electrodes. Further, in the technique described in Patent Document 3, as in Patent Documents 1 and 2, when fusion starts, heat shrinkage may occur at once. In addition, sufficient heat-resistant shrinkage effect may not be obtained unless the particles are highly crystallized by heat treatment after the particle coating is formed.
複合銅粒子における無機酸化物粒子には、上述のとおり、（イ）母粒子の表面近傍に完全包埋されているものと、（ロ）母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとの少なくとも２種類があるところ、（イ）の無機酸化物粒子に関し「母粒子の表面近傍に完全包埋」とは、母粒子の半径をｒとした場合、母粒子の中心位置を基準としてｒ／３以上の外側の領域であって、かつ母粒子の表面から無機酸化物粒子の直径分だけ内側の領域に、無機酸化物粒子が主として存在していることをいう。この様子は、ＦＩＢ処理によって複合銅粒子の断面を露出させ、ＴＥＭで観察した後、ＥＤＳで元素分析を行うことで確認できる。一方、（ロ）の無機酸化物粒子に関し「母粒子の表面に一部露出した状態」とは、無機酸化物粒子の直径を基準として、好ましくは５５〜９０％が包埋されていることをいう。無機酸化物粒子がこの程度の深さで母粒子中に包埋されていることで、複合銅粒子を例えばペーストとして使用した場合、ペースト工程時のシェアが加わったときに、母粒子から無機酸化物粒子が脱落しにくくなるという有利な効果が奏される。またすべての無機酸化物粒子を母粒子内に完全包埋させないことによって、銅の表面が完全に露出してしまうことが防止され、耐熱収縮性が向上する。 As described above, the inorganic oxide particles in the composite copper particles include (i) those that are completely embedded in the vicinity of the surface of the mother particles, and (b) the mother particles that are partially exposed on the surface of the mother particles. Where there are at least two types of those embedded in the inorganic oxide particles in (a), “completely embedded in the vicinity of the surface of the mother particles” means that when the radius of the mother particles is r, The inorganic oxide particles are mainly present in the outer region of r / 3 or more with respect to the center position of the mother particle and in the inner region by the diameter of the inorganic oxide particle from the surface of the mother particle. Say. This state can be confirmed by exposing the cross section of the composite copper particles by FIB treatment, observing with TEM, and performing elemental analysis with EDS. On the other hand, regarding the inorganic oxide particles (b), “partially exposed on the surface of the mother particles” means that preferably 55 to 90% is embedded based on the diameter of the inorganic oxide particles. Say. The inorganic oxide particles are embedded in the mother particles at such a depth, so that when composite copper particles are used as a paste, for example, when the share during the paste process is added, the inorganic particles are oxidized from the mother particles. There is an advantageous effect that it becomes difficult for the particles to fall off. Further, by not completely embedding all the inorganic oxide particles in the mother particles, it is possible to prevent the copper surface from being completely exposed and to improve the heat shrinkage resistance.
複合銅粒子における（イ）の無機酸化物粒子と（ロ）の無機酸化物粒子との比率は、重量比で表して（イ）：（ロ）＝１：９〜８：２、特に４：６〜６：４であることが、耐熱収縮性、熱収縮速度の点から好ましい。この比率は次の方法で求めることができる。 The ratio of the inorganic oxide particles (a) to the inorganic oxide particles (b) in the composite copper particles is expressed as a weight ratio of (a) :( b) = 1: 9 to 8: 2, particularly 4: 6-6: 4 is preferable from the viewpoint of heat shrinkage resistance and heat shrinkage rate. This ratio can be obtained by the following method.
まず、銅を溶解させず、かつ無機酸化物粒子を溶解させる液を調製する。無機酸化物粒子が例えばＳｉＯ2の粒子である場合には、１ｍｏｌ／Ｌ以上の濃度の水酸化ナトリウム水溶液を用いることができる。無機酸化物粒子がＡｌ2Ｏ3の粒子である場合には、９ｍｏｌ／Ｌ以上の濃度の水酸化ナトリウム水溶液を用い、８０℃以上に加熱することで、Ａｌ2Ｏ3の粒子を溶解させることができる。無機酸化物粒子がＴｉＯ2の粒子である場合には、２．７ｍｏｌ／Ｌ以上の濃度のフッ酸水溶液を用いることができる。この液に複合銅粒子を投入し、該粒子の表面に露出している無機酸化物粒子を溶解させる。例えば液５００ｍＬに対して複合銅粒子２０ｇを投入する。無機酸化物粒子の溶解は、例えば温度２５〜３０℃にて約６０分行う（ただし、Ａｌ2Ｏ3粒子を除く。）。液に溶解した無機酸化物粒子の量をＩＣＰで測定することで、複合銅粒子の表面に露出している無機酸化物粒子の量を求める。次いで、複合銅粒子を液から分離し、銅を溶解する液（例えば硝酸等の鉱酸の水溶液）に投入して銅を完全溶解させる。次いでこの液に、無機酸化物粒子を溶解させる剤（例えば無機酸化物粒子がＳｉＯ2である場合にはフッ酸水溶液）を添加して、無機酸化物粒子を完全溶解させる。このようにして得られた液を測定対象としてＩＣＰ分析を行い、母粒子中に完全包埋されている無機酸化物粒子の量を求める。 First, a liquid that does not dissolve copper and dissolves inorganic oxide particles is prepared. When the inorganic oxide particles are, for example, SiO 2 particles, an aqueous sodium hydroxide solution having a concentration of 1 mol / L or more can be used. When the inorganic oxide particles are Al 2 O 3 particles, the Al 2 O 3 particles are dissolved by heating to 80 ° C. or higher using a sodium hydroxide aqueous solution having a concentration of 9 mol / L or higher. Can do. When the inorganic oxide particles are TiO 2 particles, a hydrofluoric acid aqueous solution having a concentration of 2.7 mol / L or more can be used. Composite copper particles are introduced into this liquid, and inorganic oxide particles exposed on the surface of the particles are dissolved. For example, 20 g of composite copper particles are added to 500 mL of liquid. The inorganic oxide particles are dissolved, for example, at a temperature of 25 to 30 ° C. for about 60 minutes (except for Al 2 O 3 particles). By measuring the amount of inorganic oxide particles dissolved in the liquid by ICP, the amount of inorganic oxide particles exposed on the surface of the composite copper particles is determined. Next, the composite copper particles are separated from the liquid and put into a liquid for dissolving copper (for example, an aqueous solution of a mineral acid such as nitric acid) to completely dissolve the copper. Next, an agent that dissolves the inorganic oxide particles (for example, a hydrofluoric acid aqueous solution when the inorganic oxide particles are SiO 2 ) is added to the liquid to completely dissolve the inorganic oxide particles. ICP analysis is performed using the liquid thus obtained as a measurement target to determine the amount of inorganic oxide particles that are completely embedded in the mother particles.
本発明者らの検討の結果、複合銅粒子の熱収縮開始温度のコントロールには、無機酸化物粒子の大きさが支配的であることが判明した。詳細には、粒径の大きな無機酸化物粒子は、粒径の小さなものに比べて表面格子エネルギーが大きいので、融着しにくい。そして、無機酸化物粒子自体の融着温度が高いほど、母粒子の融着温度も高くなる。したがって、無機酸化物粒子の粒径をコントロールすることで、複合銅粒子の熱収縮開始温度をコントロールすることができる。この観点から、無機酸化物粒子の一次粒子の平均粒径は、５〜５０ｎｍに設定し、好ましくは１０〜４０ｎｍに設定する。前記の平均粒径は、ＴＥＭや粒度分布測定器によって求めることができる。 As a result of the study by the present inventors, it has been found that the size of the inorganic oxide particles is dominant in controlling the thermal shrinkage start temperature of the composite copper particles. Specifically, the inorganic oxide particles having a large particle size have a larger surface lattice energy than those having a small particle size, and thus are difficult to fuse. The higher the fusion temperature of the inorganic oxide particles themselves, the higher the fusion temperature of the mother particles. Therefore, the thermal shrinkage start temperature of the composite copper particles can be controlled by controlling the particle size of the inorganic oxide particles. From this viewpoint, the average particle size of the primary particles of the inorganic oxide particles is set to 5 to 50 nm, preferably 10 to 40 nm. The average particle diameter can be determined by TEM or a particle size distribution measuring instrument.
無機酸化物粒子の粒径は上述のとおりであるところ、母粒子の粒径との相対的な関係では、無機酸化物粒子の粒径は、母粒子の粒径の１／１０〜１／２００、特に１／２０〜１／１００とすることが好ましい。つまり、無機酸化物粒子は、母粒子に比べて比較的小さくても、複合銅粒子の熱収縮性のコントロールに寄与する。このことに関連して、母粒子の一次粒子の平均粒径は、０．２〜１０μｍに設定し、好ましくは０．３〜５μｍに設定する。母粒子の平均粒径が０．２μｍに満たないと、無機酸化物粒子の大きさに対して母粒子の大きさがそれに近づきすぎ、複合銅粒子の導電性が低下するなどの不都合が生じてしまう。一方、１０μｍを超える場合には、母粒子自体の焼結温度が高くなるので、無機酸化物粒子を用いる必要性がなくなる。この平均粒径は、無機酸化物粒子の一次粒子の平均粒径の測定法と同様にして測定することができる。 The particle size of the inorganic oxide particles is as described above. In terms of the relative relationship with the particle size of the mother particles, the particle size of the inorganic oxide particles is 1/10 to 1/200 of the particle size of the mother particles. In particular, it is preferable to set to 1/20 to 1/100. That is, the inorganic oxide particles contribute to the control of the heat shrinkability of the composite copper particles even if they are relatively small compared to the mother particles. In this connection, the average particle size of the primary particles of the mother particles is set to 0.2 to 10 μm, preferably 0.3 to 5 μm. If the average particle size of the base particles is less than 0.2 μm, the size of the base particles is too close to the size of the inorganic oxide particles, resulting in inconveniences such as a decrease in the conductivity of the composite copper particles. End up. On the other hand, if it exceeds 10 μm, the sintering temperature of the mother particles themselves becomes high, and thus there is no need to use inorganic oxide particles. This average particle size can be measured in the same manner as the method for measuring the average particle size of the primary particles of the inorganic oxide particles.
上述の微粒の無機酸化物粒子は、加水分解可能な無機化合物を加水分解又は重縮合させて無機酸化物ゾルを製造することで得ることができる。例えばＳｉＯ2のゾルを得る場合には、水ガラスを原料とし酸による中和法若しくはイオン交換法、四塩化珪素の熱分解で得る方法、又は特開平６−３１６４０７号公報に記載の方法を採用することができる。Ａｌ2Ｏ3のゾルを得る場合には、無機酸や有機酸等の一般に酸の存在下で金属アルミニウムを直接水と反応させることにより製造する方法、又は特開平５−２４８２４号公報に記載の方法を採用することができる。ＴｉＯ2のゾルを得る場合には、チタン塩水溶液に陰イオン交換体を接触させる方法、アンモニア水等のアルカリを加えて中和する方法、炭酸アンモニウム等のアンモニウム水溶液を加える方法、又は特開平８−２０８２２８号公報に記載の方法を採用することができる。ＣｅＯ2のゾルを得る場合には、不活性ガス雰囲気下に水性媒体中でセリウム塩とアルカリ性物質とを所定のモル比で反応させて水酸化セリウム懸濁液を生成した後、大気圧下１０〜９５℃で酸素含有ガスを吹き込み酸化させる方法、又は特開２００２−３２６８１２号公報に記載の方法を採用することができる。ＺｒＯ2のゾルを得る場合には、水溶性ジルコニウム塩を含む水溶液にアルカリを加えて得たジルコニウム水酸化物を加水分解させる方法、カルボン酸又はヒドロキシカルボン酸の存在下で、ジルコニウム化合物水溶液にアルカリ水溶液を加えて得たジルコニウム水酸化物ゲル分散液を限外濾過洗浄及びイオン交換樹脂で脱イオンし水熱処理する方法、又は特開２００８−２９０８９６号公報に記載の方法を採用することができる。 The fine inorganic oxide particles described above can be obtained by hydrolyzing or polycondensing a hydrolyzable inorganic compound to produce an inorganic oxide sol. For example, when a sol of SiO 2 is obtained, a neutralization method or ion exchange method using water glass as a raw material, a method obtained by thermal decomposition of silicon tetrachloride, or a method described in JP-A-6-316407 is employed. can do. When obtaining a sol of Al 2 O 3 , a method of producing by reacting metallic aluminum directly with water in the presence of an acid such as an inorganic acid or an organic acid, or a method described in JP-A-5-24824 The method can be adopted. When obtaining a TiO 2 sol, a method of bringing an anion exchanger into contact with an aqueous solution of titanium salt, a method of neutralizing by adding an alkali such as ammonia water, a method of adding an aqueous solution of ammonium carbonate or the like, or JP-A-8 The method described in JP-A-208228 can be employed. In the case of obtaining a CeO 2 sol, a cerium hydroxide suspension is produced by reacting a cerium salt and an alkaline substance in an aqueous medium in an inert gas atmosphere at a predetermined molar ratio. A method in which oxygen-containing gas is blown and oxidized at ˜95 ° C. or a method described in JP-A-2002-326812 can be employed. When obtaining a ZrO 2 sol, a method of hydrolyzing a zirconium hydroxide obtained by adding an alkali to an aqueous solution containing a water-soluble zirconium salt, an aqueous solution of a zirconium compound in the presence of a carboxylic acid or a hydroxycarboxylic acid. A zirconium hydroxide gel dispersion obtained by adding an aqueous solution may be subjected to ultrafiltration washing and deionization with an ion exchange resin and hydrothermal treatment, or a method described in JP-A-2008-290896.
複合銅粒子の熱収縮速度のコントロールに関しては、複合銅粒子中に含まれる無機酸化物粒子の量が支配的であることが判明した。先に述べたとおり、一般に、銅粒子はその融着が開始されると熱収縮速度が一気に高まるところ、適切な量の無機酸化物粒子を含有させることで、熱収縮速度の増加が抑制されるので、収縮を徐々に進行させることができる。この観点から、無機酸化物粒子は、複合銅粒子全体に対して０．１〜５重量％、好ましくは０．２〜３重量％含有される。無機酸化物粒子の含有量が０．１重量％に満たないと、母粒子の表面において、焼結し易い部位であるステップやキンク部を無機酸化物粒子で覆いきれなくなってしまう。逆に無機酸化物粒子の含有量が５重量％を超えると、不導体である無機酸化物の量が増えてしまい、複合銅粒子の導電性を低下させてしまうので、電子材料用途に不向きになってしまう。複合銅粒子における無機酸化物粒子の含有量は、複合銅粒子を溶解させ、先に述べたＩＣＰ分析法によって求めることができる。なお、複合銅粒子の焼結が一気に進行してしまうと、焼結体にクラックが生じやすくなり、また基材から剥離しやすくなるという不都合がある。更に、焼結温度の幅が狭く、操作性に劣ったり、基材の同時焼成が難しくなり、製造経費が高くなったりするといった不都合もある。 It has been found that the amount of inorganic oxide particles contained in the composite copper particles is dominant with respect to the control of the heat shrinkage rate of the composite copper particles. As described above, generally, when the fusion of copper particles starts, the heat shrinkage rate increases at a stretch. By containing an appropriate amount of inorganic oxide particles, the increase in heat shrinkage rate is suppressed. Therefore, the contraction can be gradually advanced. From this viewpoint, the inorganic oxide particles are contained in an amount of 0.1 to 5% by weight, preferably 0.2 to 3% by weight, based on the entire composite copper particles. If the content of the inorganic oxide particles is less than 0.1% by weight, the step or kink portion, which is a portion that is easily sintered, cannot be covered with the inorganic oxide particles on the surface of the mother particles. Conversely, if the content of the inorganic oxide particles exceeds 5% by weight, the amount of the inorganic oxide that is a nonconductor increases, and the conductivity of the composite copper particles is reduced. turn into. The content of the inorganic oxide particles in the composite copper particles can be obtained by dissolving the composite copper particles and using the ICP analysis method described above. In addition, if the sintering of the composite copper particles proceeds at a stretch, there is an inconvenience that cracks are likely to occur in the sintered body, and it is easy to peel from the substrate. Furthermore, there are also inconveniences such as a narrow sintering temperature range, inferior operability, difficulty in simultaneous firing of base materials, and high manufacturing costs.
上述したとおり、複合銅粒子の焼結時の熱収縮のコントロールのためには、該粒子の表面に露出している無機酸化物粒子及び複合銅粒子の表面近傍において完全包埋されている無機酸化物粒子が重要である。逆の見方をすれば、母粒子の中心域に無機酸化物粒子が存在していても、複合銅粒子の耐熱収縮性の向上にはほとんど寄与しない。この観点から、母粒子の中心域においては、無機酸化物粒子が実質的に非存在状態になっていることが好ましい。ここで言う「中心域」とは、大体の目安として母粒子の中心から半径１／３以内の領域のことである。 As described above, in order to control the thermal shrinkage during sintering of the composite copper particles, the inorganic oxide particles exposed on the surface of the particles and the inorganic oxide completely embedded in the vicinity of the surface of the composite copper particles are used. Object particles are important. In other words, even if the inorganic oxide particles are present in the central region of the mother particles, they hardly contribute to the improvement of the heat shrinkage resistance of the composite copper particles. From this viewpoint, it is preferable that the inorganic oxide particles are substantially absent in the central region of the mother particles. The “central region” here refers to a region within a radius of 1/3 from the center of the mother particle as a rough guide.
一方、複合銅粒子の表面は、銅と無機酸化物粒子から構成されていることが好ましい。換言すれば、複合銅粒子の表面は、無機酸化物粒子のみから構成されていないことが好ましい。この構成によって、複合銅粒子どうしの電気的接触を確実に行うことができ、焼結体の電気伝導性の低下を抑制することができる。 On the other hand, the surface of the composite copper particles is preferably composed of copper and inorganic oxide particles. In other words, it is preferable that the surface of the composite copper particles is not composed only of inorganic oxide particles. With this configuration, it is possible to reliably make electrical contact between the composite copper particles, and it is possible to suppress a decrease in electrical conductivity of the sintered body.
無機酸化物粒子としては、金属元素又は非金属元素の酸化物を用いることができる。無機酸化物粒子は、例えばｐＨ＝７．５〜１２の主としてアルカリ性の水溶液中で、表面にＯＨ基が生成するものであることが好ましい（この理由については後述する）。換言すれば、アルカリ性の水溶液中で少なくとも一部が溶解可能であり、その溶解によって表面に水酸基が生成可能なものであることが好ましい。無機酸化物粒子の好ましい具体例としては、金属元素の酸化物の粒子として、アルミナ（Ａｌ2Ｏ3）、チタニア（ＴｉＯ2）、セリア（ＣｅＯ2）、ジルコニア（ＺｒＯ2）等が挙げられ、非金属元素の酸化物の粒子としてシリカ（ＳｉＯ2）等が挙げられる。 As the inorganic oxide particles, an oxide of a metal element or a nonmetal element can be used. The inorganic oxide particles are preferably those in which OH groups are generated on the surface in a mainly alkaline aqueous solution having a pH of 7.5 to 12 (the reason will be described later). In other words, it is preferable that at least a part can be dissolved in an alkaline aqueous solution and a hydroxyl group can be generated on the surface by the dissolution. Preferable specific examples of the inorganic oxide particles include alumina (Al 2 O 3 ), titania (TiO 2 ), ceria (CeO 2 ), zirconia (ZrO 2 ) and the like as metal element oxide particles. silica (SiO 2), and the like as a particle of oxide nonmetallic element.
無機酸化物粒子の形状は本発明において特に臨界的なものではない。例えば球状、多面体状、針状、紡錘状、扁平状、金平糖状等の形状のものを用いることができる。一般的に言えば、等方性のある形状のもの、例えば球状の無機酸化物粒子を用いることで、満足すべき耐熱収縮性を得ることができる。 The shape of the inorganic oxide particles is not particularly critical in the present invention. For example, a spherical shape, a polyhedron shape, a needle shape, a spindle shape, a flat shape, a confetti shape, or the like can be used. Generally speaking, satisfactory heat shrinkage can be obtained by using isotropic shapes such as spherical inorganic oxide particles.
一方、母粒子の形状も本発明において特に臨界的なものではなく、無機酸化物粒子と同様に、例えば球状、多面体状、針状、紡錘状、扁平状、金平糖状等の形状のものを用いることができる。一般的には、球状や扁平状のものを用いることが好ましい。母粒子は銅からなるものである。あるいは、母粒子は銅合金であってもよい。 On the other hand, the shape of the mother particle is not particularly critical in the present invention, and, for example, a spherical shape, a polyhedral shape, a needle shape, a spindle shape, a flat shape, a confetti shape, etc. are used similarly to the inorganic oxide particles. be able to. In general, it is preferable to use a spherical or flat shape. The mother particles are made of copper. Alternatively, the mother particle may be a copper alloy.
複合銅粒子においては、無機酸化物粒子に比べて母粒子の方が十分に大きいので、複合銅粒子の形状は母粒子の形状と実質的に同じになっている。また、粒径に関しても、複合銅粒子の粒径は、母粒子の粒径と実質的に同じになっている。 In the composite copper particles, since the mother particles are sufficiently larger than the inorganic oxide particles, the shape of the composite copper particles is substantially the same as the shape of the mother particles. Further, regarding the particle size, the particle size of the composite copper particles is substantially the same as the particle size of the mother particles.
次に、複合銅粒子の好ましい製造方法について説明する。複合銅粒子は、銅イオン若しくは銅を含むイオン種、銅酸化物又は銅水酸化物及び無機酸化物粒子を含む水溶液に還元剤を添加して、銅の還元を行う工程を有する方法によって好適に製造される。つまり銅の湿式還元によって好適に製造される。 Next, the preferable manufacturing method of composite copper particle is demonstrated. The composite copper particles are suitably used by a method having a step of reducing copper by adding a reducing agent to an aqueous solution containing copper ions or copper ion or copper oxide or copper hydroxide and inorganic oxide particles. Manufactured. That is, it is suitably manufactured by wet reduction of copper.
湿式還元に用いられる液としては、例えば硫酸銅、塩化銅、酢酸銅、硝酸銅等の水溶性銅塩の水溶液等を用いることができる。あるいは、酸化銅等の銅酸化物や水酸化銅（Ｃｕ（ＯＨ）2）等の銅水酸化物の水性スラリーを用いることもできる。水溶液及び水性スラリーのいずれの場合であっても、液中に含まれる銅の濃度は０．１〜５ｍｏｌ／Ｌ、特に１〜３ｍｏｌ／Ｌであることが好ましい。この液と、無機酸化物粒子とを混合する。特に、無機酸化物粒子をゾルの状態で混合することが、母粒子内に均一に無機酸化物粒子が分布しやすくなるという点から好ましい。 As a liquid used for wet reduction, for example, an aqueous solution of a water-soluble copper salt such as copper sulfate, copper chloride, copper acetate, copper nitrate, or the like can be used. Alternatively, an aqueous slurry of copper oxide such as copper oxide or copper hydroxide such as copper hydroxide (Cu (OH) 2 ) can also be used. In any case of the aqueous solution and the aqueous slurry, the concentration of copper contained in the liquid is preferably 0.1 to 5 mol / L, particularly preferably 1 to 3 mol / L. This liquid is mixed with inorganic oxide particles. In particular, it is preferable to mix the inorganic oxide particles in a sol state from the viewpoint that the inorganic oxide particles are easily distributed uniformly in the mother particles.
このようにして得られた混合液においては、銅１ｇに対して無機酸化物粒子が１〜１００ｍｇ、特に１〜５０ｍｇの割合で含まれていることが好ましい。この混合液に還元剤を添加して銅の還元を行う。還元剤としては、例えばヒドラジン系還元剤、ホルムアルデヒド、テトラホウ酸カリウム、ジメチルアミンボラン、還元糖等を用いることができる。 In the mixed solution thus obtained, the inorganic oxide particles are preferably contained in an amount of 1 to 100 mg, particularly 1 to 50 mg per 1 g of copper. A reducing agent is added to this mixed solution to reduce copper. As the reducing agent, for example, hydrazine-based reducing agent, formaldehyde, potassium tetraborate, dimethylamine borane, reducing sugar and the like can be used.
母粒子の粒径や形状を制御する目的で、前記の混合液には還元剤以外の薬剤を添加することもできる。そのような薬剤としては、例えば水溶性のリン系化合物等が挙げられる。 For the purpose of controlling the particle size and shape of the mother particles, a chemical other than the reducing agent can be added to the mixed solution. Examples of such agents include water-soluble phosphorus compounds.
本製造方法においては銅の還元前から反応系に無機酸化物粒子を存在させておき、無機酸化物の存在下に銅の還元を行う。このような条件を採用することで、銅の母粒子の成長過程において生ずることのあるキンク（表面の角が出ている部分）やステップ（表面の単原子層の段になっている部分）等の反応性に富む部位に、無機酸化物粒子が特異的に吸着するようになる。その結果、母粒子における不安定な部位が無機酸化物粒子によって選択的に保護され、焼結時の熱収縮がコントロールされる。 In this production method, inorganic oxide particles are present in the reaction system before the reduction of copper, and copper is reduced in the presence of the inorganic oxide. By adopting such conditions, kinks (parts where the corners of the surface appear) and steps (parts where the monolayers of the surface are stepped) that may occur during the growth of the copper mother particles, etc. The inorganic oxide particles are specifically adsorbed on the highly reactive sites. As a result, unstable sites in the mother particles are selectively protected by the inorganic oxide particles, and heat shrinkage during sintering is controlled.
特に、無機酸化物粒子として、アルカリ性の水溶液中で、表面にＯＨ基が生成するものを用いると、無機酸化物粒子と母粒子の表面に吸着したＯＨ基とが加水分解反応によって結合し、無機酸化物粒子が母粒子内部に取り込まれやすくなるので好ましい。 In particular, when an inorganic oxide particle having an OH group formed on the surface in an alkaline aqueous solution is used, the inorganic oxide particle and the OH group adsorbed on the surface of the mother particle are bonded by a hydrolysis reaction, and the inorganic oxide particle is inorganic. It is preferable because the oxide particles are easily taken into the mother particles.
還元によって生成する母粒子の粒径（この粒径は、複合銅粒子の粒径と実質的に同じである）や形状は、例えば前記の混合液のｐＨや温度、還元剤の添加速度や濃度等を適切に調節することによって容易にコントロールできる。 The particle size of the mother particles produced by reduction (this particle size is substantially the same as the particle size of the composite copper particles) and shape are, for example, the pH and temperature of the mixed solution, the addition rate and concentration of the reducing agent It can be easily controlled by adjusting etc. appropriately.
本製造方法において、銅からなる母粒子の表面近傍に無機酸化物粒子を完全包埋させ、かつ母粒子の表面に無機酸化物粒子を一部露出した状態で包埋させる手段として、次に述べる操作（１）や（２）を採用することが好ましい。（１）及び（２）の操作はそれぞれ単独で行ってもよく、あるいは両者を組み合わせてもよい。 In the present production method, the means for completely embedding the inorganic oxide particles in the vicinity of the surface of the mother particles made of copper and embedding the inorganic oxide particles partially exposed on the surface of the mother particles will be described below. It is preferable to employ the operations (1) and (2). The operations (1) and (2) may be performed alone or in combination.
操作（１）
無機酸化物粒子の共存下、還元剤を添加し銅イオン（Ｃｕ2+）を還元してＣｕ2Ｏを生成させた後、再度還元剤を添加しこのＣｕ2Ｏを更に還元してＣｕを生成させるときに、無機酸化物粒子（好ましくは無機酸化物粒子のゾル）を、当初水性液中に存在するものとは別に添加する。
Operation (1)
In the presence of inorganic oxide particles, a reducing agent is added to reduce copper ions (Cu 2+ ) to form Cu 2 O. Then, a reducing agent is added again to further reduce the Cu 2 O to reduce Cu. When formed, inorganic oxide particles (preferably a sol of inorganic oxide particles) are added separately from those initially present in the aqueous liquid.
操作（１）によって本発明の複合銅粒子が製造される過程を、図１に模式的に示すイメージ図に基づき説明する。なお、図１においては、無機酸化物粒子としてＳｉＯ2を用いているが、これ以外の無機酸化物粒子を用いた場合であっても反応は同様に進行する。また、以下の説明には完全に解明されていない部分があり、本発明者らの推測が一部含まれている。 A process of producing the composite copper particles of the present invention by the operation (1) will be described based on an image diagram schematically shown in FIG. In FIG. 1, SiO 2 is used as the inorganic oxide particles, but the reaction proceeds in the same manner even when other inorganic oxide particles are used. In addition, the following explanation includes a part that has not been completely elucidated, and includes a part of the assumptions of the present inventors.
まず図１（ａ）に示すように、銅源（図示せず）が含まれる水性液中にＳｉＯ2粒子を共存させる。この状態下に還元剤を添加すると、図１（ｂ）に示すように、銅イオン（Ｃｕ2+）が還元されてＣｕ2Ｏ粒子が生成する。Ｃｕ2Ｏ粒子の生成においては、液中に存在しているＳｉＯ2粒子がＣｕ2Ｏ粒子内に取り込まれる。ＳｉＯ2粒子は液中にも存在している。また、この時点ではＣｕの核粒子は生成していない。 First, as shown in FIG. 1 (a), SiO 2 particles are allowed to coexist in an aqueous liquid containing a copper source (not shown). When a reducing agent is added under this condition, as shown in FIG. 1B, copper ions (Cu 2+ ) are reduced and Cu 2 O particles are generated. In the production of Cu 2 O particles, SiO 2 particles present in the liquid are taken into the Cu 2 O particles. SiO 2 particles are also present in the liquid. At this time, no Cu core particles are generated.
次に、当初系中に存在するものとは別にＳｉＯ2粒子を系に添加し、次いで還元剤を系に再度添加する。還元剤の再度の添加によって図１（ｃ）に示すようにＣｕ2Ｏ粒子が溶解して小さくなり、それとともに系内にＣｕの核粒子が生成する。Ｃｕの核粒子は結晶密度が高いので、Ｃｕ2Ｏ粒子と異なり、ＳｉＯ2粒子はＣｕの核粒子内に取り込まれない。還元剤の作用でＣｕ2Ｏ粒子の還元が進行すると、図１（ｄ）に示すように、Ｃｕ2Ｏ粒子の溶解が更に進行してその粒径が小さくなり、それとともにＣｕの核粒子の成長が進行する。この場合、Ｃｕ2Ｏ粒子の粒径が小さくなると、その比表面積が大きくなり、それに伴って溶解速度も高くなる。その結果、系内に溶解したＣｕ+イオンの量も増加するので、Ｃｕの核粒子の成長速度も増加する。Ｃｕの核粒子の成長速度も増加に起因して、Ｃｕの核粒子の結晶化密度が低下し、Ｃｕ粒子内にＳｉＯ2粒子が取り込まれ始める。 Next, SiO 2 particles are added to the system separately from those initially present in the system, and then the reducing agent is added again to the system. By adding the reducing agent again, as shown in FIG. 1 (c), the Cu 2 O particles dissolve and become small, and at the same time, Cu core particles are generated in the system. Since Cu core particles have a high crystal density, unlike Cu 2 O particles, SiO 2 particles are not incorporated into Cu core particles. When the reduction of the Cu 2 O particles proceeds by the action of the reducing agent, as shown in FIG. 1 (d), the dissolution of the Cu 2 O particles further proceeds and the particle size becomes smaller. Growth progresses. In this case, when the particle size of the Cu 2 O particles is reduced, the specific surface area is increased and the dissolution rate is increased accordingly. As a result, the amount of Cu + ions dissolved in the system also increases, so that the growth rate of Cu core particles also increases. Due to the increase in the growth rate of the Cu core particles, the crystallization density of the Cu core particles decreases, and SiO 2 particles begin to be taken into the Cu particles.
Ｃｕ粒子内にＳｉＯ2粒子が取り込まれると、図１（ｅ）に示すように、液中のＳｉＯ2粒子の量が次第に減少する。しかし、それと並行してＣｕ2Ｏ粒子の溶解も進行しているので、その進行によってＳｉＯ2粒子が液中に補充される。このことから明らかなように、Ｃｕ粒子に取り込まれるＳｉＯ2粒子は、取り込みの初期段階では液中に存在しているＳｉＯ2粒子が主たるものであり、そのＳｉＯ2粒子は主として複合銅粒子中に完全包埋される。また、取り込みが進行するに連れて、Ｃｕ2Ｏ粒子から放出されたＳｉＯ2粒子がＣｕ粒子に取り込まれるようになり、その粒子は複合銅粒子中において一部が露出した状態でＣｕ粒子中に包埋される。取り込みの初期段階で液中に存在しているＳｉＯ2粒子は、主として２回目に添加されたものである。一方、Ｃｕ2Ｏ粒子から放出されたＳｉＯ2粒子は、主として製造の当初に液中に添加されたものである。したがって、製造の当初に液中に添加するＳｉＯ2粒子の量と、２回目に添加するＳｉＯ2粒子の量とをバランスさせることで、完全包埋されるＳｉＯ2粒子と一部露出したＳｉＯ2粒子との量をコントロールすることができる。このようにして、図１（ｆ）に示すように、目的とする複合銅粒子が得られる。 When the SiO 2 particles are taken into the Cu particles, the amount of SiO 2 particles in the liquid gradually decreases as shown in FIG. However, since the dissolution of Cu 2 O particles is also progressing in parallel, the SiO 2 particles are replenished in the liquid by the progress. As is clear from this, the SiO 2 particles incorporated into the Cu particles are mainly SiO 2 particles present in the liquid at the initial stage of incorporation, and the SiO 2 particles are mainly contained in the composite copper particles. Fully embedded. Further, as the uptake proceeds, the SiO 2 particles released from the Cu 2 O particles are taken into the Cu particles, and the particles are partly exposed in the Cu particles in the composite copper particles. Embedded. The SiO 2 particles present in the liquid at the initial stage of uptake are mainly added in the second time. On the other hand, the SiO 2 particles released from the Cu 2 O particles are mainly added to the liquid at the beginning of production. Therefore, the amount of SiO 2 particles added to the liquid during the initial manufacturing, by balancing the amount of SiO 2 particles added to the second, SiO 2 exposed SiO 2 particles and a part that is fully embedded The amount of particles can be controlled. In this way, the desired composite copper particles are obtained as shown in FIG.
操作（２）
無機酸化物粒子の共存下、銅イオン（Ｃｕ2+）の還元中における液のｐＨをアルカリ性側に調整する。具体的には好ましくはｐＨ＝７．５〜１２、更に好ましくはｐＨ＝８〜１１に調整する。そして液のｐＨをこの範囲に調整してから、還元剤を添加する。還元反応中に反応系のｐＨが低下してきたら、アルカリ性の物質を更に加えてｐＨが前記の範囲内に維持されるようにする。反応系のｐＨを前記の範囲内に維持することで、還元によって生成した銅粒子の核の表面にＯＨ基が存在し、そのＯＨ基が無機酸化物粒子を引き寄せる。銅の粒子の核は無機酸化物粒子を引き寄せたまま粒成長していくので、無機酸化物粒子は銅の母粒子内に取り込まれる。もちろん母粒子の表面にも無機酸化物粒子が吸着する。この場合、系のｐＨが高いほどＯＨ基が多数存在するので、無機酸化物粒子が母粒子内部に取り込まれやすい。すなわちｐＨ制御により取り込まれる無機酸化物粒子の量を制御できる。
Operation (2)
In the presence of inorganic oxide particles, the pH of the liquid during the reduction of copper ions (Cu 2+ ) is adjusted to the alkaline side. Specifically, it is preferably adjusted to pH = 7.5 to 12, more preferably pH = 8 to 11. Then, after adjusting the pH of the liquid to this range, a reducing agent is added. If the pH of the reaction system falls during the reduction reaction, an alkaline substance is further added so that the pH is maintained within the above range. By maintaining the pH of the reaction system within the above range, OH groups exist on the surface of the core of the copper particles generated by the reduction, and the OH groups attract the inorganic oxide particles. Since the core of the copper particles grows while attracting the inorganic oxide particles, the inorganic oxide particles are taken into the copper base particles. Of course, the inorganic oxide particles are also adsorbed on the surface of the mother particles. In this case, the higher the system pH is, the more OH groups are present, so that the inorganic oxide particles are easily taken into the mother particles. That is, the amount of inorganic oxide particles taken in can be controlled by pH control.
操作（２）によって本発明の複合銅粒子が製造される過程を、図２に模式的に示すイメージ図に基づき説明する。なお、図２においても、無機酸化物粒子としてＳｉＯ2を用いているが、これ以外の無機酸化物粒子を用いた場合であっても反応は同様に進行する。また、以下の説明には完全に解明されていない部分があり、本発明者らの推測が一部含まれている。 The process in which the composite copper particles of the present invention are produced by the operation (2) will be described based on an image diagram schematically shown in FIG. In FIG. 2, SiO 2 is used as the inorganic oxide particles, but the reaction proceeds in the same manner even when other inorganic oxide particles are used. In addition, the following explanation includes a part that has not been completely elucidated, and includes a part of the assumptions of the present inventors.
まず銅源（図示せず）が含まれる水性液中にＳｉＯ2粒子を共存させる。この状態下に還元剤を添加すると、図２（ａ）に示すように、銅イオン（Ｃｕ2+）が還元されてＣｕ2Ｏ粒子が生成する。Ｃｕ2Ｏ粒子の生成においては、液中に存在しているＳｉＯ2粒子がＣｕ2Ｏ粒子内に取り込まれる。ＳｉＯ2粒子は液中にも存在している。また、この時点ではＣｕの核粒子は生成していない。 First, SiO 2 particles are allowed to coexist in an aqueous liquid containing a copper source (not shown). When a reducing agent is added under this condition, as shown in FIG. 2A, copper ions (Cu 2+ ) are reduced and Cu 2 O particles are generated. In the production of Cu 2 O particles, SiO 2 particles present in the liquid are taken into the Cu 2 O particles. SiO 2 particles are also present in the liquid. At this time, no Cu core particles are generated.
還元剤の追加添加によって還元が進行すると、図２（ｂ）に示すように、一旦生成したＣｕ2Ｏ粒子が溶解して小さくなり、それとともに系内にＣｕの核粒子が生成する。Ｃｕの核粒子は結晶密度が高いので、Ｃｕ2Ｏ粒子と異なり、ＳｉＯ2粒子はＣｕの核粒子内に取り込まれない。Ｃｕ2Ｏ粒子の還元が更に進行すると、図２（ｃ）に示すように、Ｃｕ2Ｏ粒子の溶解が更に進行してその粒径が小さくなり、それとともにＣｕの核粒子の成長が進行する。この場合、Ｃｕ2Ｏ粒子の粒径が小さくなると、その比表面積が大きくなり、それに伴って溶解速度も高くなる。その結果、液中に溶解したＣｕ+イオンの量も増加するので、Ｃｕの核粒子の成長速度も増加する。Ｃｕの核粒子の成長速度も増加に起因して、Ｃｕの核粒子の結晶化密度が低下し、Ｃｕ粒子内にＳｉＯ2粒子が取り込まれ始める。 When the reduction proceeds by the addition of a reducing agent, as shown in FIG. 2 (b), once generated Cu 2 O particles are dissolved and become smaller, and at the same time, Cu core particles are generated in the system. Since Cu core particles have a high crystal density, unlike Cu 2 O particles, SiO 2 particles are not incorporated into Cu core particles. When the reduction of the Cu 2 O particles further proceeds, as shown in FIG. 2 (c), the dissolution of the Cu 2 O particles further proceeds to reduce the particle size, and the growth of the Cu core particles proceeds with it. . In this case, when the particle size of the Cu 2 O particles is reduced, the specific surface area is increased and the dissolution rate is increased accordingly. As a result, since the amount of Cu + ions dissolved in the liquid also increases, the growth rate of Cu core particles also increases. Due to the increase in the growth rate of the Cu core particles, the crystallization density of the Cu core particles decreases, and SiO 2 particles begin to be taken into the Cu particles.
Ｃｕ粒子内にＳｉＯ2粒子が取り込まれるメカニズムは、次のとおりであると本発明者らは考えている。すなわち、図２（ｄ）に示すように、成長過程にあるＣｕ粒子はその表面にＯＨ基を有している。一方、液中がアルカリ性であることに起因して、ＳｉＯ2粒子の表面にもＯＨ基が存在している。したがって、Ｃｕ粒子の表面のＯＨ基と、ＳｉＯ2粒子の表面のＯＨ基とが加水分解し、両粒子どうしが引き寄せ合う。それによって、Ｃｕ粒子内にＳｉＯ2粒子が取り込まれる。したがってＳｉＯ2粒子の取り込みは、ＳｉＯ2粒子の表面のＯＨ基の数が多いほど起こりやすくなる。 The present inventors consider that the mechanism by which SiO 2 particles are taken into Cu particles is as follows. That is, as shown in FIG. 2D, the Cu particles in the growth process have OH groups on the surface. On the other hand, due to the alkali in the liquid, OH groups are also present on the surface of the SiO 2 particles. Therefore, the OH group on the surface of the Cu particle and the OH group on the surface of the SiO 2 particle are hydrolyzed, and the two particles are attracted to each other. Thereby, SiO 2 particles are taken into the Cu particles. Thus the SiO 2 particles uptake, is likely to occur as the number of OH groups on the surface of the SiO 2 particles.
Ｃｕ粒子の成長に伴い液のｐＨは次第に低下してくるところ、図２（ｅ）に示すように、アルカリ物質の添加によって液のｐＨが７．５〜１２の範囲に維持されるようにすることで、ＳｉＯ2粒子の表面のＯＨ基の数を維持できる。それによって、ＳｉＯ2粒子の取り込みの程度が低下することを防止できる。つまり、液のｐＨの調整によって、ＳｉＯ2粒子の取り込みの程度をコントロールでき、完全包埋されるＳｉＯ2粒子と一部露出したＳｉＯ2粒子との量をコントロールすることができる。このようにして、図２（ｆ）に示すように、目的とする複合銅粒子が得られる。 As the Cu particles grow, the pH of the liquid gradually decreases. As shown in FIG. 2E, the pH of the liquid is maintained in the range of 7.5 to 12 by adding an alkaline substance. Thus, the number of OH groups on the surface of the SiO 2 particles can be maintained. Thereby, it is possible to prevent the degree of incorporation of SiO 2 particles from being lowered. That is, by adjusting the pH of the liquid, the degree of incorporation of SiO 2 particles can be controlled, and the amount of completely embedded SiO 2 particles and partially exposed SiO 2 particles can be controlled. In this way, the desired composite copper particles are obtained as shown in FIG.
以上の各操作によれば、完全包埋される無機酸化物粒子と一部露出した無機酸化物粒子との量を精密にコントロールすることができるので、得られる複合銅粒子の焼結挙動を精密に制御できるという利点がある。また、このようにして得られた複合銅粒子においては、その表面に一部露出している無機酸化物粒子が、アンカー効果等によって確実に母粒子に保持されているので、該複合銅粒子に外力を加えても無機酸化物粒子の脱落が起こりづらくなっている。したがって、得られた複合銅粒子に例えば圧力を加えて扁平状に加工しても、加工中における無機酸化物粒子の脱落が防止される。 According to each of the above operations, the amount of the completely embedded inorganic oxide particles and the partially exposed inorganic oxide particles can be precisely controlled, so that the sintering behavior of the obtained composite copper particles can be precisely controlled. There is an advantage that can be controlled. Further, in the composite copper particles obtained in this manner, the inorganic oxide particles partially exposed on the surface are securely held by the mother particles by the anchor effect or the like. Even when an external force is applied, it is difficult for the inorganic oxide particles to fall off. Therefore, even if pressure is applied to the obtained composite copper particles, for example, and processing into a flat shape, dropping of the inorganic oxide particles during processing is prevented.
得られた複合銅粒子は、例えばこれをガラス粉末及び有機ビヒクルと混合して導電ペーストとして用いることができる。この導電ペーストは、例えば積層セラミックコンデンサなどの積層セラミック電子部品の外部電極作製のために用いることができる。特に、ニッケルを主成分とする内部電極と電気的に接続される外部電極を形成するために用いられる。外部電極の形成においては、セラミックから構成される積層セラミック電子部品本体の外表面上に、導電ペーストを塗布した後、高温での熱処理（例えば４００〜１０００℃）で焼結を行う。この場合、本発明の複合銅粒子を含む導電ペーストを用いれば、焼結時における塗布体の熱収縮がコントロールされるので、焼結によって生ずる焼結体が部品本体から剥離したり、焼結体にクラックが生じたりすることを効果的に防止することができる。 The obtained composite copper particles can be used, for example, as a conductive paste by mixing it with glass powder and an organic vehicle. This conductive paste can be used for manufacturing an external electrode of a multilayer ceramic electronic component such as a multilayer ceramic capacitor. In particular, it is used to form an external electrode that is electrically connected to an internal electrode mainly composed of nickel. In the formation of the external electrode, a conductive paste is applied on the outer surface of a multilayer ceramic electronic component body made of ceramic, and then sintered by high-temperature heat treatment (for example, 400 to 1000 ° C.). In this case, if the conductive paste containing the composite copper particles of the present invention is used, the thermal contraction of the coated body at the time of sintering is controlled. It is possible to effectively prevent cracks from occurring.
以下、実施例により本発明を更に詳細に説明する。しかしながら本発明の範囲は、かかる実施例に制限されない。特に断らない限り、「％」は「重量％」を意味する。 Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” means “% by weight”.
〔実施例１〕
まず、３．６Ｍの硫酸銅水溶液９Ｌを５０℃に加熱保持し、この硫酸銅水溶液へＳｉＯ2ゾル（ゾル濃度２０％、平均粒径５ｎｍ）を５０ｇ添加した。その後、濃度２５％のアンモニア水溶液１３００ｍｌと、濃度２５％の水酸化ナトリウム水溶液４２５０ｇを遂次添加した。ここに、ヒドラジン一水和物（ヒドラジン系還元剤）４５０ｇとｐＨ調整剤としてのアンモニア水溶液（濃度２５％）５９１ｍｌとを連続添加し、液のｐＨを１１に維持しつつ亜酸化銅スラリーを得た（第１還元処理）。そして、還元反応を完全に行うため、更に３０分間撹拌を続けた。
[Example 1]
First, 9 L of a 3.6 M aqueous copper sulfate solution was heated and held at 50 ° C., and 50 g of SiO 2 sol (sol concentration 20%, average particle size 5 nm) was added to the aqueous copper sulfate solution. Thereafter, 1300 ml of a 25% aqueous ammonia solution and 4250 g of a 25% aqueous sodium hydroxide solution were successively added. Here, 450 g of hydrazine monohydrate (hydrazine-based reducing agent) and 591 ml of an aqueous ammonia solution (concentration 25%) as a pH adjuster were continuously added to obtain a cuprous oxide slurry while maintaining the pH of the solution at 11. (First reduction treatment). Then, in order to complete the reduction reaction, stirring was continued for another 30 minutes.
この亜酸化銅スラリーにヒドラジン一水和物（ヒドラジン系還元剤）３００ｇを添加した。更に６０分間撹拌を行い、還元反応を完全に行わせ、目的とする複合銅粒子を還元析出させた（第２還元処理）。ヒドラジン一水和物（ヒドラジン系還元剤）を二回目に添加した後、系のｐＨが徐々に低下する。この場合、ＳｉＯ2ゾルを安定に取り込ませるために、５％の水酸化ナトリウム水溶液を添加して系のｐＨが１１となるよう調整を行った。 To this cuprous oxide slurry, 300 g of hydrazine monohydrate (hydrazine-based reducing agent) was added. Stirring was further performed for 60 minutes to complete the reduction reaction, and target composite copper particles were reduced and precipitated (second reduction treatment). After the second addition of hydrazine monohydrate (hydrazine reducing agent), the pH of the system gradually decreases. In this case, in order to stably incorporate the SiO 2 sol, a 5% sodium hydroxide aqueous solution was added to adjust the pH of the system to 11.
得られた複合銅粒子を濾過洗浄（その際の表面処理剤としてデカン酸添加）して回収した。その後７０℃、５時間の加熱乾燥を行い、更に解砕処理を施した。得られた複合銅粒子の平均粒径は０．３μｍであり、その中に０．５％のＳｉＯ2粒子が含まれていた。上述した方法によって、ＳｉＯ2粒子の存在部位を調べたところ、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとが存在していることが確認された。また母粒子の中心域にはＳｉＯ2粒子は存在していなかった。母粒子の表面近傍に完全包埋されているＳｉＯ2粒子と、母粒子の表面に一部露出した状態になっているＳｉＯ2粒子との重量比を上述した方法で測定したところ、前者：後者＝６：４であった。 The obtained composite copper particles were collected by filtration and washing (adding decanoic acid as a surface treatment agent at that time). Thereafter, it was heated and dried at 70 ° C. for 5 hours, and further crushed. The obtained composite copper particles had an average particle diameter of 0.3 μm and contained 0.5% of SiO 2 particles. As a result of examining the existence site of the SiO 2 particles by the above-described method, it was found that the SiO 2 particles were completely embedded in the vicinity of the surface of the mother particles and partially embedded in the surface of the mother particles. It is confirmed that there is something that exists. Further, no SiO 2 particles were present in the central region of the mother particles. When the weight ratio between the SiO 2 particles completely embedded in the vicinity of the surface of the mother particles and the SiO 2 particles partially exposed on the surface of the mother particles was measured by the method described above, the former: the latter = 6: 4.
〔実施例２〕
まず、３．６Ｍの硫酸銅水溶液９Ｌを５０℃に加熱保持し、この硫酸銅水溶液へＳｉＯ2ゾル（ゾル濃度２０％、平均粒径３０ｎｍ）を２５０ｇ添加した。その後、濃度２５％アンモニア水溶液１３００ｍｌと濃度２５％の水酸化ナトリウム水溶液４２５０ｇを遂次添加した。ここにヒドラジン一水和物４５０ｇとｐＨ調整剤としてのアンモニア水溶液５９１ｍｌとを連続添加し、亜酸化銅スラリーを得た（第１還元処理）。そして還元反応を行うために、更に３０分間攪拌を続けた。
[Example 2]
First, 9 L of a 3.6 M aqueous copper sulfate solution was heated and held at 50 ° C., and 250 g of SiO 2 sol (sol concentration 20%, average particle size 30 nm) was added to the aqueous copper sulfate solution. Thereafter, 1300 ml of a 25% aqueous ammonia solution and 4250 g of a 25% aqueous sodium hydroxide solution were successively added. Here, 450 g of hydrazine monohydrate and 591 ml of an aqueous ammonia solution as a pH adjuster were continuously added to obtain a cuprous oxide slurry (first reduction treatment). In order to carry out the reduction reaction, stirring was continued for another 30 minutes.
この亜酸化銅スラリーに、当初液中に存在するものとは別にＳｉＯ2ゾル（ゾル濃度２０％、平均粒径３０ｎｍ）を２５０ｇ添加し、その後ヒドラジン一水和物３００ｇを添加した。更に６０分間攪拌を行い、還元反応を完全に行わせ、目的とする複合銅粒子を還元析出させた（第２還元処理）。 250 g of SiO 2 sol (sol concentration 20%, average particle size 30 nm) was added to this cuprous oxide slurry separately from the one present in the initial solution, and then 300 g of hydrazine monohydrate was added. The mixture was further stirred for 60 minutes to complete the reduction reaction, and the target composite copper particles were reduced and precipitated (second reduction treatment).
その後は実施例１と同様にして複合銅粒子を得た。得られた複合銅粒子の平均粒径は０．３μｍであり、その中に５％のＳｉＯ2粒子が含まれていた。上述した方法によって、ＳｉＯ2粒子の存在部位を調べたところ、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとが存在していることが確認された。また母粒子の中心域にはＳｉＯ2粒子は存在していなかった。母粒子の表面近傍に完全包埋されているＳｉＯ2粒子と、母粒子の表面に一部露出した状態になっているＳｉＯ2粒子との重量比を上述した方法で測定したところ、前者：後者＝６：４であった。 Thereafter, composite copper particles were obtained in the same manner as in Example 1. The obtained composite copper particles had an average particle size of 0.3 μm, and contained 5% of SiO 2 particles. As a result of examining the existence site of the SiO 2 particles by the above-described method, it was found that the SiO 2 particles were completely embedded in the vicinity of the surface of the mother particles and partially embedded in the surface of the mother particles. It is confirmed that there is something that exists. Further, no SiO 2 particles were present in the central region of the mother particles. When the weight ratio between the SiO 2 particles completely embedded in the vicinity of the surface of the mother particles and the SiO 2 particles partially exposed on the surface of the mother particles was measured by the method described above, the former: the latter = 6: 4.
〔実施例３〕
まず、３．６Ｍの硫酸銅水溶液９Ｌを５０℃に加熱保持し、この硫酸銅水溶液へＳｉＯ2ゾル（ゾル濃度２０％、平均粒径２０ｎｍ）を３４ｇ添加した。その後、グリシン４５ｍｌ、濃度２５％の水酸化ナトリウム水溶液１７４３ｇを遂次添加した。ここに、グルコース５２５ｇを添加し、亜酸化銅スラリーを得た（第１還元処理）。そして、還元反応を完全に行うため、更に３０分間撹拌を続けた。
Example 3
First, 9 L of a 3.6 M aqueous copper sulfate solution was heated and maintained at 50 ° C., and 34 g of SiO 2 sol (sol concentration 20%, average particle size 20 nm) was added to the aqueous copper sulfate solution. Thereafter, 45 ml of glycine and 1743 g of an aqueous sodium hydroxide solution having a concentration of 25% were successively added. Glucose 525g was added here and the cuprous oxide slurry was obtained (1st reduction process). Then, in order to complete the reduction reaction, stirring was continued for another 30 minutes.
この亜酸化銅スラリーに、当初液中に存在するものとは別にＳｉＯ2ゾル（ゾル濃度２０％、平均粒径２０ｎｍ）１６ｇ添加し、その後ヒドラジン一水和物（ヒドラジン系還元剤）３７５ｇを添加した。更に３０分間撹拌を行い、還元反応を完全に行わせ、目的とする複合銅粒子を還元析出させた（第２還元処理）。 16 g of SiO 2 sol (sol concentration 20%, average particle size 20 nm) is added to this cuprous oxide slurry separately from the one present in the initial solution, and then 375 g of hydrazine monohydrate (hydrazine reducing agent) is added. did. The mixture was further stirred for 30 minutes to complete the reduction reaction, and the target composite copper particles were reduced and precipitated (second reduction treatment).
得られた複合銅粒子を濾過洗浄（その際の表面処理剤としてオレイン酸を添加）して回収した。その後７０℃、５時間の加熱乾燥を行った。得られた複合銅粒子の平均粒径は２μｍであり、その中に０．５％のＳｉＯ2粒子が含まれていた。上述した方法によって、ＳｉＯ2粒子の存在部位を調べたところ、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとが存在していることが確認された。また母粒子の中心域にはＳｉＯ2粒子は存在していなかった。母粒子の表面近傍に完全包埋されているＳｉＯ2粒子と、母粒子の表面に一部露出した状態になっているＳｉＯ2粒子との重量比を上述した方法で測定したところ、前者：後者＝３：７であった。 The obtained composite copper particles were recovered by filtration and washing (added oleic acid as a surface treating agent at that time). Thereafter, heat drying was performed at 70 ° C. for 5 hours. The obtained composite copper particles had an average particle diameter of 2 μm and contained 0.5% of SiO 2 particles. As a result of examining the existence site of the SiO 2 particles by the above-described method, it was found that the SiO 2 particles were completely embedded in the vicinity of the surface of the mother particles and partially embedded in the surface of the mother particles. It is confirmed that there is something that exists. Further, no SiO 2 particles were present in the central region of the mother particles. When the weight ratio between the SiO 2 particles completely embedded in the vicinity of the surface of the mother particles and the SiO 2 particles partially exposed on the surface of the mother particles was measured by the method described above, the former: the latter = 3: 7.
〔実施例４〕
まず、３．６Ｍの硫酸銅水溶液９Ｌを５０℃に加熱保持し、この硫酸銅水溶液へＳｉＯ2ゾル（ゾル濃度２０％、平均粒径３０ｎｍ）を１６６ｇ添加した。次いで燐酸三ナトリウム１１．ｇを添加した。その後アンモニア水溶液（濃度２５％）２５３７ｍｌを添加して、銅塩化合物スラリーを得た。そして、銅塩化合物スラリーを３０分静置して熟成させた。次に、ヒドラジン一水和物（ヒドラジン系還元剤）４５０ｇとｐＨ調整剤としてのアンモニア水溶液（濃度２５％）５９１ｍｌとを連続添加し、液のｐＨを８に維持しつつ亜酸化銅スラリーを得た（第１還元処理）。そして、還元反応を完全に行うため、更に３０分間撹拌を続けた。
Example 4
First, 9 L of a 3.6 M aqueous copper sulfate solution was heated and held at 50 ° C., and 166 g of SiO 2 sol (sol concentration 20%, average particle size 30 nm) was added to the aqueous copper sulfate solution. Then trisodium phosphate 11. g was added. Thereafter, 2537 ml of an aqueous ammonia solution (concentration 25%) was added to obtain a copper salt compound slurry. The copper salt compound slurry was allowed to stand for 30 minutes for aging. Next, 450 g of hydrazine monohydrate (hydrazine-based reducing agent) and 591 ml of an aqueous ammonia solution (concentration 25%) as a pH adjuster are continuously added to obtain a cuprous oxide slurry while maintaining the pH of the solution at 8. (First reduction treatment). Then, in order to complete the reduction reaction, stirring was continued for another 30 minutes.
この亜酸化銅スラリーに、当初液中に存在するものとは別にＳｉＯ2ゾル（ゾル濃度２０％、平均粒径３０ｎｍ）を３３４ｇ添加し、その後ヒドラジン一水和物（ヒドラジン系還元剤）６００ｇを添加した。更に１８０分間撹拌を行い、還元反応を完全に行わせ、目的とする複合銅粒子を還元析出させた（第２還元処理）。ヒドラジン一水和物（ヒドラジン系還元剤）を二回目に添加した後、系のｐＨが徐々に低下する。この場合、ＳｉＯ2ゾルを安定に取り込ませるために、５％の水酸化ナトリウム水溶液を添加して系のｐＨが８となるよう調整を行った。 To this cuprous oxide slurry, 334 g of SiO 2 sol (sol concentration 20%, average particle size 30 nm) is added separately from the one present in the initial solution, and then 600 g of hydrazine monohydrate (hydrazine reducing agent) is added. Added. Further, stirring was performed for 180 minutes to complete the reduction reaction, and target composite copper particles were reduced and precipitated (second reduction treatment). After the second addition of hydrazine monohydrate (hydrazine reducing agent), the pH of the system gradually decreases. In this case, in order to stably incorporate the SiO 2 sol, a 5% aqueous sodium hydroxide solution was added to adjust the pH of the system to 8.
得られた複合銅粒子を濾過洗浄（その際の表面処理剤としてオレイン酸を添加）して回収した。その後７０℃、５時間の加熱乾燥を行った。得られた複合銅粒子の平均粒径は２μｍであり、その中に５％のＳｉＯ2粒子が含まれていた。上述した方法によって、ＳｉＯ2粒子の存在部位を調べたところ、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとが存在していることが確認された。また母粒子の中心域にはＳｉＯ2粒子は存在していなかった。母粒子の表面近傍に完全包埋されているＳｉＯ2粒子と、母粒子の表面に一部露出した状態になっているＳｉＯ2粒子との重量比を上述した方法で測定したところ、前者：後者＝６：４であった。 The obtained composite copper particles were recovered by filtration and washing (added oleic acid as a surface treating agent at that time). Thereafter, heat drying was performed at 70 ° C. for 5 hours. The average particle diameter of the obtained composite copper particles was 2 μm, and 5% of SiO 2 particles were contained therein. As a result of examining the existence site of the SiO 2 particles by the above-described method, it was found that the SiO 2 particles were completely embedded in the vicinity of the surface of the mother particles and partially embedded in the surface of the mother particles. It is confirmed that there is something that exists. Further, no SiO 2 particles were present in the central region of the mother particles. When the weight ratio between the SiO 2 particles completely embedded in the vicinity of the surface of the mother particles and the SiO 2 particles partially exposed on the surface of the mother particles was measured by the method described above, the former: the latter = 6: 4.
〔実施例５〕
まず、３．６Ｍの硫酸銅水溶液９Ｌを５０℃に加熱保持し、この硫酸銅水溶液へＳｉＯ2ゾル（ゾル濃度２０％、平均粒径２０ｎｍ）を１６ｇ添加した。その後、濃度２５％の水酸化ナトリウム水溶液６Ｌを遂次添加した。ここに、グルコース１７００ｇを添加し、亜酸化銅スラリーを得た（第１還元処理）。そして、還元反応を完全に行うため、更に３０分間撹拌を続けた。
Example 5
First, 9 L of a 3.6 M aqueous copper sulfate solution was heated and held at 50 ° C., and 16 g of SiO 2 sol (sol concentration 20%, average particle size 20 nm) was added to the aqueous copper sulfate solution. Thereafter, 6 L of a 25% sodium hydroxide aqueous solution was successively added. Glucose 1700g was added here and the cuprous oxide slurry was obtained (1st reduction process). Then, in order to complete the reduction reaction, stirring was continued for another 30 minutes.
この亜酸化銅スラリーに、当初液中に存在するものとは別にＳｉＯ2ゾル（ゾル濃度２０％、平均粒径２０ｎｍ）３４ｇ、アラビアゴムを１０ｇ添加し、その後グリシン１６０ｇ、ヒドラジン１水和物（ヒドラジン系還元剤）３０００ｇを遂次添加した。更に３０分間撹拌を行い、還元反応を完全に行わせ、目的とする複合銅粒子を還元析出させた（第２還元処理）。 To this cuprous oxide slurry, 34 g of SiO 2 sol (sol concentration 20%, average particle size 20 nm) and 10 g of gum arabic are added separately from those present in the initial solution, and then 160 g of glycine and hydrazine monohydrate ( Subsequently, 3000 g of a hydrazine reducing agent was added. The mixture was further stirred for 30 minutes to complete the reduction reaction, and the target composite copper particles were reduced and precipitated (second reduction treatment).
得られた複合銅粒子を濾過洗浄して回収した。その後７０℃、５時間の加熱乾燥を行った。得られた複合銅粒子の平均粒径は４μｍであり、その中に０．５％のＳｉＯ2粒子が含まれていた。上述した方法によって、ＳｉＯ2粒子の存在部位を調べたところ、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとが存在していることが確認された。また母粒子の中心域にはＳｉＯ2粒子は存在していなかった。母粒子の表面近傍に完全包埋されているＳｉＯ2粒子と、母粒子の表面に一部露出した状態になっているＳｉＯ2粒子との重量比を上述した方法で測定したところ、前者：後者＝７：３であった。 The obtained composite copper particles were recovered by filtration and washing. Thereafter, heat drying was performed at 70 ° C. for 5 hours. The obtained composite copper particles had an average particle diameter of 4 μm and contained 0.5% of SiO 2 particles. As a result of examining the existence site of the SiO 2 particles by the above-described method, it was found that the SiO 2 particles were completely embedded in the vicinity of the surface of the mother particles and partially embedded in the surface of the mother particles. It is confirmed that there is something that exists. Further, no SiO 2 particles were present in the central region of the mother particles. When the weight ratio between the SiO 2 particles completely embedded in the vicinity of the surface of the mother particles and the SiO 2 particles partially exposed on the surface of the mother particles was measured by the method described above, the former: the latter = 7: 3.
〔実施例６〕
実施例４において、ＳｉＯ2ゾルに代えてＡｌ2Ｏ3ゾル（ゾル濃度２０％、平均粒径１０ｎｍ）を用い、これを総量が５０ｇになるように添加した。Ａｌ2Ｏ3ゾルは分割添加ではなく、銅が還元される前の水溶液中に一括添加した。二回目のヒドラジン一水和物（ヒドラジン系還元剤）添加後のｐＨが９となるよう系のｐＨの調整を行った。また表面処理剤としてステアリン酸を使用した。これら以外は実施例４と同様の操作により複合銅粒子を得た。得られた複合銅粒子の平均粒径は２μｍであり、その中に０．５％のＡｌ2Ｏ3粒子が含まれていた。上述した方法によって、Ａｌ2Ｏ3粒子の存在部位を調べたところ、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとが存在していることが確認された。また母粒子の中心域にはＡｌ2Ｏ3粒子は存在していなかった。母粒子の表面近傍に完全包埋されているＡｌ2Ｏ3粒子と、母粒子の表面に一部露出した状態になっているＡｌ2Ｏ3粒子との重量比を上述した方法で測定したところ、前者：後者＝４：６であった。
Example 6
In Example 4, instead of SiO 2 sol, Al 2 O 3 sol (sol concentration: 20%, average particle size: 10 nm) was used and added so that the total amount was 50 g. The Al 2 O 3 sol was not added in portions, but was added all at once in the aqueous solution before copper was reduced. The pH of the system was adjusted so that the pH was 9 after the second addition of hydrazine monohydrate (hydrazine reducing agent). Further, stearic acid was used as a surface treatment agent. Except for these, composite copper particles were obtained in the same manner as in Example 4. The average particle diameter of the obtained composite copper particles was 2 μm, and 0.5% Al 2 O 3 particles were contained therein. When the existence site of the Al 2 O 3 particles was examined by the above-described method, the Al 2 O 3 particles were found to be completely embedded in the vicinity of the surface of the mother particles or partially exposed on the surface of the mother particles. It was confirmed that there was something buried. In addition, Al 2 O 3 particles were not present in the central region of the mother particles. When the weight ratio of Al 2 O 3 particles completely embedded in the vicinity of the surface of the mother particles to Al 2 O 3 particles that are partially exposed on the surface of the mother particles is measured by the method described above. The former: the latter = 4: 6.
〔実施例７〕
実施例４において、ＳｉＯ2ゾルに代えてＡｌ2Ｏ3ゾル（ゾル濃度２０％、平均粒径５０ｎｍ）を用い、これを総量が５００ｇになるように添加した。Ａｌ2Ｏ3ゾルは２５０ｇずつ２回に分けて分割添加したが、二回目のヒドラジン一水和物（ヒドラジン系還元剤）添加後のｐＨ調整は行わなかった。また表面処理剤としてステアリン酸を使用した。これら以外は実施例４と同様の操作により複合銅粒子を得た。得られた複合銅粒子の平均粒径は２μｍであり、その中に５％のＡｌ2Ｏ3粒子が含まれていた。上述した方法によって、Ａｌ2Ｏ3粒子の存在部位を調べたところ、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとが存在していることが確認された。また母粒子の中心域にはＡｌ2Ｏ3粒子は存在していなかった。母粒子の表面近傍に完全包埋されているＡｌ2Ｏ3粒子と、母粒子の表面に一部露出した状態になっているＡｌ2Ｏ3粒子との重量比を上述した方法で測定したところ、前者：後者＝６：４であった。
Example 7
In Example 4, instead of SiO 2 sol, Al 2 O 3 sol (sol concentration 20%, average particle size 50 nm) was used and added so that the total amount became 500 g. Al 2 O 3 sol was added in portions in 250 g portions, but the pH was not adjusted after the second addition of hydrazine monohydrate (hydrazine reducing agent). Further, stearic acid was used as a surface treatment agent. Except for these, composite copper particles were obtained in the same manner as in Example 4. The average particle diameter of the obtained composite copper particles was 2 μm, and 5% Al 2 O 3 particles were contained therein. When the existence site of the Al 2 O 3 particles was examined by the above-described method, the Al 2 O 3 particles were found to be completely embedded in the vicinity of the surface of the mother particles or partially exposed on the surface of the mother particles. It was confirmed that there was something buried. In addition, Al 2 O 3 particles were not present in the central region of the mother particles. When the weight ratio of Al 2 O 3 particles completely embedded in the vicinity of the surface of the mother particles to Al 2 O 3 particles that are partially exposed on the surface of the mother particles is measured by the method described above. The former: the latter = 6: 4.
〔実施例８〕
実施例６において、Ａｌ2Ｏ3ゾルに代えてＴｉＯ2ゾル（ゾル濃度２０％、平均粒径４０ｎｍ）を用い、これを総量が５０ｇになるように添加した。また表面処理剤としてラウリン酸を使用した。これら以外は実施例６と同様の操作により複合銅粒子を得た。得られた複合銅粒子の平均粒径は２μｍであり、その中に０．５％のＴｉＯ2粒子が含まれていた。上述した方法によって、ＴｉＯ2粒子の存在部位を調べたところ、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとが存在していることが確認された。また母粒子の中心域にはＴｉＯ2粒子は存在していなかった。母粒子の表面近傍に完全包埋されているＴｉＯ2粒子と、母粒子の表面に一部露出した状態になっているＴｉＯ2粒子との重量比を上述した方法で測定したところ、前者：後者＝４：６であった。
Example 8
In Example 6, TiO 2 sol (sol concentration 20%, average particle size 40 nm) was used instead of Al 2 O 3 sol, and this was added so that the total amount was 50 g. Moreover, lauric acid was used as a surface treating agent. Except these, composite copper particles were obtained in the same manner as in Example 6. The average particle diameter of the obtained composite copper particles was 2 μm, and 0.5% of TiO 2 particles were contained therein. When the existence site of TiO 2 particles was examined by the above-described method, it was found that the TiO 2 particles were embedded in the mother particles in a state of being completely embedded in the vicinity of the surface of the mother particles or partially exposed on the surface of the mother particles. It is confirmed that there is something that exists. Further, TiO 2 particles were not present in the central region of the mother particles. The weight ratio between the TiO 2 particles completely embedded in the vicinity of the surface of the mother particles and the TiO 2 particles partially exposed on the surface of the mother particles was measured by the method described above. = 4: 6.
〔実施例９〕
実施例７において、Ａｌ2Ｏ3ゾルに代えてＴｉＯ2ゾル（ゾル濃度２０％、平均粒径５０ｎｍ）を用い、これを総量が５００ｇになるように、２５０ｇずつ２回に分けて分割添加した。また表面処理剤としてラウリン酸を使用した。これら以外は実施例７と同様の操作により複合銅粒子を得た。得られた複合銅粒子の平均粒径は２μｍであり、その中に５％のＴｉＯ2粒子が含まれていた。上述した方法によって、ＴｉＯ2粒子の存在部位を調べたところ、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとが存在していることが確認された。また母粒子の中心域にはＴｉＯ2粒子は存在していなかった。母粒子の表面近傍に完全包埋されているＴｉＯ2粒子と、母粒子の表面に一部露出した状態になっているＴｉＯ2粒子との重量比を上述した方法で測定したところ、前者：後者＝６：４であった。
Example 9
In Example 7, TiO 2 sol (sol concentration 20%, average particle size 50 nm) was used instead of Al 2 O 3 sol, and this was dividedly added in two portions of 250 g so that the total amount became 500 g. . Moreover, lauric acid was used as a surface treating agent. Except these, composite copper particles were obtained in the same manner as in Example 7. The average particle diameter of the obtained composite copper particles was 2 μm, and 5% of TiO 2 particles were contained therein. When the existence site of TiO 2 particles was examined by the above-described method, it was found that the TiO 2 particles were embedded in the mother particles in a state of being completely embedded in the vicinity of the surface of the mother particles or partially exposed on the surface of the mother particles. It is confirmed that there is something that exists. Further, TiO 2 particles were not present in the central region of the mother particles. The weight ratio between the TiO 2 particles completely embedded in the vicinity of the surface of the mother particles and the TiO 2 particles partially exposed on the surface of the mother particles was measured by the method described above. = 6: 4.
〔評価１〕
各実施例で得られた複合銅粒子、及び無機酸化物粒子を含まず、かつ複合銅粒子と同じ粒径の銅粒子について、ＴＭＡを用いて熱収縮挙動を測定した。その結果を図３ないし図７に示す。測定条件は、昇温速度１０℃／ｍｉｎ、雰囲気１ｖｏｌ％Ｈ2−Ｎ2（流量１５０ｍｌ／ｍｉｎ）とした。
[Evaluation 1]
The thermal contraction behavior was measured using TMA for the copper particles not containing the composite copper particles and inorganic oxide particles obtained in each Example and having the same particle size as the composite copper particles. The results are shown in FIGS. The measurement conditions were a heating rate of 10 ° C./min and an atmosphere of 1 vol% H 2 —N 2 (flow rate: 150 ml / min).
図３ないし図７に示す結果から明らかなように、本発明の複合銅粒子は、銅単独の粒子に比べて熱収縮の開始温度が高温側にシフトしており、耐熱収縮性が高くなることが判る。また、無機酸化物粒子の量が多いほど、熱収縮がゆっくり進行することが判る。 As is clear from the results shown in FIG. 3 to FIG. 7, the composite copper particles of the present invention have a higher heat shrinkage resistance because the start temperature of heat shrinkage is shifted to a higher temperature side than the particles of copper alone. I understand. Moreover, it turns out that heat shrink progresses slowly, so that there is much quantity of inorganic oxide particle | grains.
〔評価２〕
実施例４で得られた複合銅粒子について、無機酸化物粒子の密着性を次の方法で評価した。複合銅粒子２５ｇを純水２００ｍＬ中に加え、出力４００Ｗの超音波バス中で３０分超音波処理を行った。超音波処理後の複合銅粒子を液から濾別して回収した。その後、銅を溶解する液（１４ｍｏｌ／Ｌの硝酸水溶液）に投入して銅を完全溶解させた。次いでこの液に２．７ｍｏｌ／Ｌのフッ酸水溶液を添加してＳｉＯ2を完全溶解させた。このようにして得られた液を測定対象としてＩＣＰ分析を行った。超音波処理を行う前の複合銅粒子に含まれるＳｉＯ2値を基準にして、超音波処理後に残留したＳｉＯ2量の割合を求めた。同様の測定を、特許文献１の実施例１の粒子及び特許文献３の段落〔００２４〕〜〔００２７〕に記載の粒子についても行った。これらの結果を以下の表１に示す。
[Evaluation 2]
About the composite copper particle obtained in Example 4, the adhesiveness of the inorganic oxide particle was evaluated by the following method. 25 g of composite copper particles were added to 200 mL of pure water, and sonication was performed in an ultrasonic bath with an output of 400 W for 30 minutes. The composite copper particles after ultrasonic treatment were collected by filtration from the liquid. Thereafter, the solution was poured into a solution for dissolving copper (14 mol / L nitric acid aqueous solution) to completely dissolve copper. Next, a 2.7 mol / L hydrofluoric acid aqueous solution was added to this solution to completely dissolve SiO 2 . ICP analysis was performed using the liquid thus obtained as a measurement target. Based on the SiO 2 value contained in the composite copper particles before the ultrasonic treatment, the ratio of the amount of SiO 2 remaining after the ultrasonic treatment was determined. Similar measurements were performed on the particles of Example 1 of Patent Document 1 and the particles described in paragraphs [0024] to [0027] of Patent Document 3. These results are shown in Table 1 below.
表１に示す結果から明らかなように、実施例４の複合銅粒子は、特許文献１や特許文献３の粒子に比べ、ＳｉＯ2の密着性が高いことが判る。 As is clear from the results shown in Table 1, it can be seen that the composite copper particles of Example 4 have higher SiO 2 adhesion than the particles of Patent Document 1 and Patent Document 3.
Claims (9)
無機酸化物粒子は、母粒子の表面近傍に完全包埋されているものと、母粒子の表面に一部露出した状態で、母粒子中に包埋されているものとからなり、
無機酸化物粒子が複合銅粒子全体に対して０．１〜５重量％含有されていることを特徴とする複合銅粒子。 A composite copper particle in which a plurality of inorganic oxide particles having an average particle diameter of 5 to 50 nm are contained in a mother particle containing copper having an average particle diameter of 0.2 to 10 μm,
The inorganic oxide particles consist of those that are completely embedded in the vicinity of the surface of the mother particles and those that are embedded in the mother particles in a partially exposed state on the surface of the mother particles.
A composite copper particle comprising 0.1 to 5% by weight of inorganic oxide particles based on the entire composite copper particle.
銅イオン若しくは銅を含むイオン種、銅酸化物又は銅水酸化物及び無機酸化物粒子を含む水性液に還元剤を添加して、銅の還元を行う工程を有し、
銅の還元中に、無機酸化物粒子を、当初水性液中に存在するものとは別に添加するか、
又は
銅の還元中の液のｐＨを７．５〜１２の範囲に調整することを特徴とする複合金属粒子の製造方法。 It is a manufacturing method of the composite copper particle according to claim 1,
A step of reducing copper by adding a reducing agent to an aqueous liquid containing copper ions or copper-containing ionic species, copper oxide or copper hydroxide and inorganic oxide particles,
During the reduction of copper, inorganic oxide particles are added separately from those originally present in the aqueous liquid,
Or the manufacturing method of the composite metal particle characterized by adjusting the pH of the liquid during the reduction | restoration of copper to the range of 7.5-12.
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