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Nickel-based ultrafine powder

a technology of ultrafine powder and nickel, applied in the direction of fixed capacitor details, stacked capacitors, transportation and packaging, etc., can solve the problem of dielectric materials cracking, and achieve the effect of rejecting ra

Inactive Publication Date: 2006-08-31
KAWATETABU MINING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a nickel-based ultra-fine powder with a small average particle diameter, limited number of coarse particles, and a high percentage of fine particles. This powder is suitable for use in small or high-capacity laminated ceramic capacitors with thin dielectric materials and internal electrodes. The use of this powder reduces the rejection rate in manufacturing and prevents short-circuiting caused by metal particles.

Problems solved by technology

If the quantity of fine particles that have particle diameters of 0.6 times or smaller than the average particle diameter is large, since these particles cause oxidizing expansion or low-temperature sintering easier than particles of the average particle diameter, there is possibility of causing the dielectric material to crack during the process for firing the multilayer ceramic capacitor.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0024] Three kinds of gases, which were a gas produced by subliming nickel chloride, hydrogen gas, and nitrogen gas, were mixed so that the mole ratio of the gas produced by subliming nickel chloride became 0.10, and nickel powder was manufactured by the vapor-phase reaction in a reaction column heated to 1000 to 1100° C. Image analysis was performed for 4000 particles of the obtained nickel powder using the SEM, and the flow rate of the mixed gas in the reaction column was adjusted so that the average particle diameter of primary particles became 0.2 μm.

[0025] As a result of image analysis for 4000 particles of the obtained nickel powder using the SEM, the average particle diameter of primary particles was 0.21 μm, and the number of primary particles that had particle diameters of 0.12 μm (0.6 times the average particle diameter) or less was 4% of the total number of observed particles. The number of primary particles that had particle diameters of 1 μm or larger observed for 512,...

example 2

[0028] A water slurry was prepared from nickel powder obtained by vapor-phase reaction in Example 1, the nickel powder was sufficiently dispersed in water using a dispersing machine equipped with an ultrasonic vibrator, and then the slurry was classified using an imperforate-wall basket-type centrifugal separator with a skimming pipe (internal capacity: 3 L, basket inner diameter: 300 mm, water slurry supply rate: 2.5 L / min, rotation speed: 1400 rpm), and water slurry discharged from the skimming pipe, specifically, the water slurry contained nickel powder from which coarse particles had been removed, was collected. The collected slurry was pressure dehydrated and vacuum dried to recover the nickel powder.

[0029] As a result of image analysis for 4000 particles of the obtained nickel powder using the SEM, the average particle diameter of primary particles was 0.20 μm, and the number of primary particles that had particle diameters of 0.12 μm (0.6 times the average particle diameter)...

example 3

[0030] Three kinds of gases, which were a gas produced by subliming nickel chloride, hydrogen gas, and nitrogen gas, were mixed so that the mole ratio of the gas produced by subliming nickel chloride became 0.17, and nickel powder was manufactured by the vapor-phase reaction in a reaction column heated to 1000 to 1100° C. Image analysis was performed for 4000 particles of the obtained nickel powder using the SEM, and the flow rate of the mixed gas in the reaction column was adjusted so that the average particle diameter of primary particles became 0.3 μm.

[0031] As a result of image analysis for 4000 particles of the obtained nickel powder using the SEM, the average particle diameter of primary particles was 0.27 μm, and the number of primary particles that had particle diameters of 0.16 μm (0.6 times the average particle diameter) or less was 9% of the total number of observed particles. The number of primary particles that had particle diameters of 1 μm or larger observed for 512,...

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Abstract

In order to reduce the size of a laminated ceramic capacitor by reducing the thickness of a dielectric material, to increase the number of laminated dielectric layers and electrodes, and to elevate the capacity, the quantity of coarse particles of which particle diameters exceed 1 μpm is reduced from the metal powder used in the internal electrodes. There is provided a nickel-based ultra-fine powder, wherein the average particle diameter of primary particles is 0.05 to 0.3 μm, the number of the primary particles that have a particle diameter of 1 μm or larger is 50 ppm or less relative to the total number of the particles, and the number of the primary particles that have a particle diameter of 0.6 times or smaller than the average particle diameter is 10% or less relative to the total number of the particles. The nickel-based ultra-fine powder is produced from nickel chloride vapor or the like using a vapor-phase hydrogen reduction method.

Description

TECHNICAL FIELD [0001] The present invention relates to a nickel-based ultra-fine powder used mainly in the internal electrode of a multilayer ceramic capacitor. [0002] In the present invention, the nickel-based ultra-fine powder means a nickel ultra-fine powder and a nickel alloy ultra-fine powder. The nickel ultra-fine powder means an ultra-fine powder of pure nickel or nickel that contains unavoidable impurities; and a nickel alloy means an alloy that contains nickel as the major component to which an alloy component is added, and for example, a nickel alloy that contains a small quantity of Mn, Si and the like, or an alloy of nickel and a metal easily alloyed with nickel, such as Zr, W, Cu, Cr, Fe or Al. As the nickel alloy for the internal electrode of a multilayer ceramic capacitor, the alloy that contains 95% or more by mass of nickel is preferred. BACKGROUND ART [0003] For nickel ultra-fine powder used in the internal electrode of a multilayer ceramic capacitor, with the red...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C22C1/04B22F9/12B22F1/00B22F1/052B22F9/28H01G4/008H01G4/012H01G4/12H01G4/30
CPCB22F1/0014B22F9/28B22F2998/00H01G4/008H01G4/012H01G4/30B22F1/0018B22F1/052B22F1/00B22F1/054B22F1/056
Inventor YAMANE, HIROSHIYOSHIOKA, KEIICHI
Owner KAWATETABU MINING