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
  • 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
• • 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
• • 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
  • H01B5/00—Non-insulated conductors or conductive bodies characterised by their form

Definitions

• Nickel powder method for producing the same, and conductive paste
• the present invention relates to nickel powder, a method for producing the same, and a conductive paste. Specifically, for example, nickel powder used as a raw material for nickel paste used for forming internal electrodes of a multilayer ceramic capacitor, and a method for producing the same.
• the present invention relates to a conductive paste using the nickel powder.
• Nickel powder is used in various applications.
• nickel powder is used for forming various electrodes and circuits using a conductive paste containing the nickel powder.
• a conductive paste containing the nickel powder is used as the internal electrode of a multi-layer ceramic capacitor (MLCC).
• the internal electrode uses a conductive paste containing nickel powder as a ceramic dielectric. It is obtained by applying and baking.
• Patent Document 1 discloses a suspension in which a solid compound such as a hydroxide compound such as nickel is suspended in a liquid polyol or a polyol mixture at a reaction temperature.
• a reduction method is disclosed in which the solid compound is reduced with a polyol by heating the suspension to a temperature of at least 85 ° C., and the resulting metal deposit is isolated. According to this method, nickel powder can be obtained easily and economically.
• Patent Document 1 JP 59-173206 A (first page)
• the object of the present invention is to provide fine particles, a sharp particle size distribution, a small content of impurities such as carbon or a small amount of adhesion !, nickel powder, and conductivity using the nickel powder. Is to provide a sex paste.
• the present inventor has intensively studied, and as a result, the reaction solution containing a nickel salt, a polyol and a noble metal catalyst is heated to the reduction temperature, and the reaction solution is maintained while maintaining the reduction temperature.
• the present inventors have found that the above object can be achieved when the reduction temperature is within a specific range, and the present invention has been completed.
• the method for producing nickel powder according to the present invention comprises heating a reaction solution containing a nickel salt, a polyol and a noble metal catalyst to a reduction temperature, and maintaining the reduction temperature while maintaining the reduction temperature.
• the reduction temperature is 150 ° C. to 210 ° C. and 150 ° C. to 10 ° C. lower than the boiling point of the polyol, To do.
• the reaction solution further contains a dispersing agent.
• Nickel powder according to the present invention The nickel powder according to the present invention is manufactured by the above-described manufacturing method.
• the nickel powder according to the present invention is characterized in that the average image analysis particle size is 0.02 ⁇ m to 0.2 ⁇ m.
• the nickel powder according to the present invention has an average particle diameter D of 0.1 ⁇ m to 0.5 ⁇ m.
• the nickel powder according to the present invention has a maximum particle size D of 0.7 m or less.
• the nickel powder according to the present invention provides a nickel powder characterized by having a carbon content of 0.6% by weight or less.
• Conductive paste according to the present invention is the above-mentioned The nickel powder described above is included.
• the nickel powder according to the present invention or the nickel powder obtained by the production method according to the present invention is a fine particle, has a sharp particle size distribution, and has a small content or adhesion amount of impurities such as carbon.
• the conductive paste according to the present invention uses the nickel powder according to the present invention, the nickel thick film obtained by firing the conductive paste can be thinned, and the surface of the nickel thick film is also obtained. Can be smoothed. For this reason, for example, if the conductive base according to the present invention is used, the internal electrode of the MLCC can be made thin and the surface of the electrode can be smoothed. Can be achieved.
• a method for producing a nickel powder according to the present invention comprises heating a reaction solution containing a nickel salt, a polyol and a noble metal catalyst within a specific temperature range. The nickel salt in the reaction solution is reduced while maintaining the temperature.
• nickel salt used in the present invention examples include, but are not limited to, nickel hydroxide, nickel sulfate, nickel nitrate, nickel chloride, nickel bromide, and acetic acid-packet.
• nickel hydroxide is preferable because it does not contain elements such as sulfur, carbon, and nitrogen that may adversely affect the operation of MLCC when contained in the internal electrode of MLCC.
• the nickel salts can be used singly or in combination of two or more.
• the polyol used in the present invention refers to a substance having a hydrocarbon chain and a plurality of hydroxyl groups.
• the polyol include ethylene glycol (boiling point 197 ° C), diethylene glycol (boiling point 245 ° C), triethylene glycol (boiling point 278 ° C), tetraethylene glycol (boiling point 327 ° C), 1, 2 Propanediol (boiling point 188 ° C), dipropylene glycol (boiling point 232 ° C), 1,2 butanediol (boiling point 193 ° C), 1,3 butanediol (boiling point 208 ° C), 1,4 butanediol ( The boiling point is 235 ° C), 2, 3 butanediol (boiling point 177 ° C) 1,5 pentanediol (boiling point 239 ° C) and at
• the noble metal catalyst used in the present invention promotes the reduction reaction of a nickel salt with a polyol in the reaction solution, and includes, for example, palladium chloride, palladium nitrate, palladium acetate, and salt ammonium.
• Palladium compounds such as um palladium
• silver compounds such as silver nitrate, silver lactate, silver oxide, silver sulfate, silver cyclohexanoate, silver acetate
• platinum compounds such as chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, and the like
• gold compounds such as chloroauric acid and sodium chloroaurate.
• the catalyst can be used in the form of the compound as it is or in the form of a solution of the compound.
• the reaction solution contains the above nickel salt, polyol and noble metal catalyst.
• the reaction solution can be prepared, for example, by adding a nickel salt, a polyol and a noble metal catalyst to water, stirring, and mixing.
• the noble metal catalyst is present as an aqueous solution such as palladium nitrate, Without mixing, the nickel salt, polyol and noble metal catalyst can be mixed.
• the reaction liquid is not particularly limited in the order of addition and the mixing method when mixing the nickel salt, polyol and noble metal catalyst.
• a slurry may be prepared by premixing a nickel salt, a polyol and a noble metal catalyst and, if necessary, a dispersant described later, and the slurry and the remainder of the polyol may be mixed to prepare a reaction solution.
• the reaction liquid further contains a dispersant, if necessary, because the obtained nickel powder becomes finer and the particle size distribution tends to be sharper.
• a dispersant used in the present invention include nitrogen-containing organic compounds such as polybulurpyrrolidone, polyethyleneimine, polyacrylamide, poly (2-methyl-2-oxazoline), and polyvinyl alcohol.
• polybulurpyrrolidone is preferred because the particle size distribution of the resulting nickel powder tends to be sharp.
• the above dispersants can be used singly or in combination of two or more.
• the reaction solution is heated to a reduction temperature, and the reaction solution is maintained while maintaining the reduction temperature.
• the nickel salt in the reaction solution is reduced to produce nickel powder.
• the reduction temperature is within a temperature range satisfying both of the two temperature ranges defined by different viewpoint powers.
• the temperature range defined from the first viewpoint is also referred to as the first temperature range
• the temperature range defined from the second viewpoint is also referred to as the second temperature range.
• the reduction temperature has a first temperature range of 150 ° C to 210 ° C, preferably 150 ° C to 200 ° C. When the reduction temperature is within this range, the reduction reaction is completed quickly, and the nickel powder obtained after the reaction does not easily contain impurities or adhere to the nickel powder.
• the reduction temperature is less than 150 ° C, the reduction reaction tends to be very slow, which is not preferable.
• the reduction temperature exceeds 210 ° C, it is easy to form coarse particles and the product obtained by the reduction reaction easily contains carbon and becomes nickel carbide powder.
• the reduction temperature is such that the second temperature range is 150 ° C to 10 ° C lower than the boiling point of the polyol, preferably 100 ° C to 20 ° C, more preferably 80 ° C to The temperature is 30 ° C lower.
• the reduction temperature is within this range, the resulting nickel powder is difficult to become coarse particles or agglomerate, and an organic compound that is presumed to be a reaction byproduct of polyol is applied to the surface of the nickel powder. Since adhesion can be suppressed, it is preferable.
• the reduction temperature is 150 ° C lower than the boiling point of the polyol and less than the temperature, the reduction reaction may hardly proceed. Further, if the reduction temperature is 10 ° C lower than the boiling point of the polyol and exceeds the temperature, the organic compound presumed to be a reaction by-product of the polyol tends to adhere to the surface of the nickel powder, which is not preferable.
• the resulting nickel powder when the reduction temperature satisfies both the first temperature range and the second temperature range, the resulting nickel powder is fine, the particle size distribution is sharp, and impurities such as carbon are present. The content or adhesion amount is small.
• the time for maintaining the reaction solution at the above-mentioned reduction temperature cannot be generally specified because an appropriate time varies depending on the composition of the reaction solution and the reduction temperature, but is usually 1 to 20 hours, preferably 2 to 15 hours. is there.
• the time for maintaining the reaction solution at the above-mentioned reduction temperature is within the above range, the growth of nickel powder nuclei is suppressed and the atmosphere in which many nickel powder nuclei are likely to be generated is formed. Since the grain growth of the powder is almost uniform, the resulting nickel powder It can suppress that it becomes a coarse particle or aggregates. Therefore, in the present invention, as long as the above reduction temperature is maintained for the above time, the temperature of the reaction solution may be set to a temperature outside the range of the above reduction temperature.
• the temperature of the reaction solution may be set to a temperature exceeding the reduction temperature.
• the nickel powder according to the present invention is obtained. Since the nickel powder according to the present invention is manufactured under the above conditions, it has the physical properties described below.
• Nickel powder according to the present invention is a powder having substantially a nickel force and having a substantially spherical particle shape.
• the nickel powder according to the present invention has an image analysis average particle size force of usually 0.02 ⁇ m to 0.2 m, preferably 0.03 ⁇ m to 0.1 ⁇ m.
• An image analysis average particle size of less than 0.02 m is not preferable because primary particles tend to aggregate.
• the average particle size of image analysis exceeds 0.2 / zm, the maximum value of the primary particle size becomes too large, and it becomes difficult to obtain a thin and smooth electrode film, which is not preferable.
• the image analysis average particle size is the number of times that the number of primary particles in the screen is 100 or more using a scanning electron microscope (SEM) or transmission electron microscope (TEM).
• SEM scanning electron microscope
• TEM transmission electron microscope
• the nickel powder according to the present invention has an average particle diameter D force of usually 0.1 ⁇ m.
• the nickel thick film formed of the conductive paste containing the nickel powder is made sufficiently thin 1 and the smoothness of the surface of the nickel thick film tends to deteriorate, which is not preferable.
• “D” means a recording using a Microtrack HRA manufactured by Nikkiso Co.
• the nickel powder according to the present invention has a maximum particle size D 1S of usually not more than 0. m, preferably 0.5 max.
• the nickel powder according to the present invention has a standard deviation SD of particle diameter, usually 0.05-0.2, preferably 0.05-0.1. If the SD of the nickel powder is within this range, the nickel thick film formed with the conductive paste containing the nickel powder can be easily made sufficiently thin, and the smoothness of the surface of the thick nickel film is difficult to deteriorate. Therefore, it is preferable.
• SD means the standard deviation of the particle size required when measuring the particle size distribution by the laser diffraction scattering method using Microtrack HRA manufactured by Nikkiso Co., Ltd.
• the nickel powder according to the present invention has a carbon content of usually 0.6% by weight or less, preferably 0.3% by weight or less. When the carbon content is within this range, the nickel powder has a high conductivity, which increases the MLCC capacitance and tends to increase the electrode film density.
• the nickel powder according to the present invention is produced by the nickel powder production method according to the present invention, a nickel powder having a low content of impurities such as carbon or a small amount of adhesion is obtained, and the carbon content is within the above range. It is easy to become.
• the conductive paste according to the present invention includes the nickel powder according to the present invention, and includes a resin and a solvent in addition to the nickel powder.
• the resin used in the present invention include celluloses such as ethyl cellulose and nitrocellulose, and acrylic resins such as butyl methacrylate and methyl methacrylate.
• the above-mentioned rosins can be used alone or in combination of two or more.
• the solvent used in the present invention include terpenes such as tervineol and dihydrotabinol, alcohols such as octanol and decanol, and the like. In the present invention, the above solvents may be used alone or in combination of two or more.
• the content of the nickel powder according to the present invention is usually 40 wt% to 70 wt%, preferably 50 wt% to 60 wt%. When the content of the nickel powder is within this range, the paste has good conductivity, high filling property, heat shrinkage resistance, small S, and is preferable.
• the nickel powder according to the present invention is mixed with, for example, a known paste used in the production of a conductive paste to obtain a conductive paste in which nickel powder is dispersed.
• the conductive paste can be used as, for example, a nickel paste used for forming an internal electrode of a multilayer ceramic capacitor.
• Reduction step Solution B was sent to the reaction vessel, and further 29 g (32 kg) of ethylene glycol (manufactured by Mitsui Engineering Co., Ltd.) was added and mixed to prepare a reaction solution (reaction solution A).
• reaction solution A was warmed and held at 160 ° C. for 10 hours.
• a slurry (slurry A) was obtained by these operations.
• Washing step Thereafter, 140 L of ethylene glycol in the upper part of the slurry A was discharged from the upper part of the reaction vessel. Thereafter, the remaining slurry A was subjected to suction filtration for solid-liquid separation. The separated cake was decanted with 200 L of water, and then the water was removed. The powder obtained by removing water was decanted by adding 50 L of methanol, and then methanol was removed. The powder after removal of methanol was dried at 80 ° C for 5 hours, and nickel powder was obtained.
• the obtained nickel powder was observed with a scanning electron microscope (SEM). A scanning electron micrograph of the nickel powder is shown in FIG. The obtained nickel powder was measured for image analysis average particle size, D, D, D, D, SD, and carbon residue by the following measurement method.
• Measuring method of average particle size of image analysis Sample powder was scanned using a scanning electron microscope (SEM) Observe at a magnification (50000 times) that the number of primary particles in the screen is 100 or more and perform image analysis based on the images using the IP-1000PC, a high-definition image analyzer manufactured by Asahi Engineering Co., Ltd. The average particle size of 100 primary particles was measured.
• SEM scanning electron microscope
• the particle size was D. Also,
• Carbon residue measurement method Carbon and sulfur simultaneous analyzer EMIA — 320V, manufactured by HORIBA, Ltd. Using a 320V, 0.5g sample was heated and burned with an outlet setting of 175mA, and carbon was measured by infrared absorption method. The amount was measured.
• Pre-mixing step and mixing step The pre-mixing step and the mixing step were performed in the same manner as in Example 1 to prepare a solution B.
• Reduction step Solution B was fed to the reaction vessel, and further 29 g (32 kg) of ethylene glycol (manufactured by Mitsui Engineering Co., Ltd.) was added and mixed to prepare a reaction solution (reaction solution A). When the reaction solution A was warmed and kept at 190 ° C. for 5 hours, a slurry (slurry B) was obtained.
• Washing step Thereafter, 140 L of the supernatant in the slurry B was discharged from the upper part of the reaction vessel. Thereafter, the remaining slurry B was subjected to suction filtration for solid-liquid separation. After decanting by adding 200 L of water to the separated cake, water was removed. Further, 50 L of methanol was added to the powder and decanted, and then the methanol was removed. The powder after removal of methanol was dried at 80 ° C for 5 hours to obtain nickel powder.
• the nickel powder of Example 1 has D and SD in comparison with the nickel powder of Comparative Example 1.
• the nickel powder and the conductive paste according to the present invention can be used, for example, as a nickel paste used for forming an internal electrode of a multilayer ceramic capacitor and a raw material thereof.
• FIG. 1 is a scanning electron micrograph of nickel powder of Example 1.
• FIG. 2 is a graph showing the particle size distribution of nickel powder of Example 1.
• FIG. 3 is a scanning electron micrograph of the nickel powder of Comparative Example 1.
• FIG. 4 is a graph showing the particle size distribution of the nickel powder of Comparative Example 1.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Dispersion Chemistry (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacture Of Metal Powder And Suspensions Thereof (AREA)
• Powder Metallurgy (AREA)
• Conductive Materials (AREA)
• Non-Insulated Conductors (AREA)

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• 2005
  • 2005-12-08 TW TW094143343A patent/TWI399254B/zh not_active IP Right Cessation
  • 2005-12-09 EP EP05814736A patent/EP1839784A1/de not_active Withdrawn
  • 2005-12-09 KR KR1020077012795A patent/KR101251567B1/ko not_active IP Right Cessation
  • 2005-12-09 WO PCT/JP2005/022623 patent/WO2006062186A1/ja not_active Application Discontinuation
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