Nickel powder, method for manufacturing nickel powder, internal electrode paste using nickel powder, and electronic component

Patent metadata

Field	Value
Publication number	US-2019084040-A1
Application number	US-201716085148-A
Country	US
Kind code	A1
Filing date	Mar 14, 2017
Priority date	Mar 18, 2016
Publication date	Mar 21, 2019
Grant date	—

Abstract

To provide a fine nickel powder for an internal electrode paste of an electronic component, the nickel powder obtained by a wet method and having high crystallinity, excellent sintering characteristics, and heat-shrinking characteristics. The nickel powder is obtained by precipitating nickel by a reduction reaction in a reaction solution including at least water-soluble nickel salt, salt of metal nobler than nickel, hydrazine as a reducing agent, and alkali metal hydroxide as a pH adjusting agent and water; the reaction solution is prepared by mixing a nickel salt solution including the water-soluble nickel salt and the salt of metal nobler than nickel with a mixed reducing agent solution including hydrazine and alkali metal hydroxide; and the hydrazine is additionally added to the reaction solution after a reduction reaction initiates in the reaction solution.

First claim

1 . A nickel powder having a nearly spherical particle shape, an average particle diameter of 0.05 μm to 0.5 μm, a crystallite diameter of 30 nm to 80 nm, and an amount of nitrogen of 0.02% by mass or less.

2 . The nickel powder according to claim 1 further having an amount of an alkali metal element of 0.01% by mass or less.

3 . The nickel powder according to claim 1 , wherein, when heating a pellet that is formed by pressurizing and molding the nickel powder from 25° C. to 1200° C. in an inert atmosphere or a reducing atmosphere and measuring a thermal shrinkage of the pellet based on a thickness of the pellet at 25° C., a maximum shrinkage temperature that is a temperature at a maximum shrinkage where the thermal shrinkage becomes maximum is 700° C. or more, the maximum shrinkage that is a maximum value of the thermal shrinkage at the maximum shrinkage temperature is 22% or less, and a maximum expansion amount of the pellet from the pellet at the maximum shrinkage based on the thickness of the pellet at 25° C. in a temperature range of the maximum shrinkage temperature or more and 1200° C. or less is 7.5% or less.

4 . The nickel powder according to claim 1 , wherein sulfur is included at least on a surface of the nickel powder, and an amount of the sulfur is 1.0% by mass or less.

5 . The nickel powder according to claim 1 , wherein a CV value indicating a ratio of a standard deviation of particle diameters of the nickel powder to the average particle diameter is 20% or less.

6 . A manufacturing method of nickel powder comprising a crystallization process to obtain nickel crystallization powder by precipitating nickel by a reduction reaction in a reaction solution including at least water-soluble nickel salt, metal salt of metal that is nobler than nickel, hydrazine as a reducing agent, alkali metal hydroxide as a pH adjusting agent, and water;
the reaction solution prepared by mixing a nickel salt solution including the water-soluble nickel salt and the metal salt of metal that is nobler than nickel with a mixed reducing agent solution including the hydrazine and the alkali metal hydroxide; the hydrazine additionally added to the reaction solution after a reduction reaction initiates in the reaction solution; and an amount of initial hydrazine that is hydrazine among the hydrazine being formulated in the mixed reducing agent solution set in a range of 0.05 to 1.0 at a molar ratio to nickel, and an amount of additional hydrazine among the hydrazine being additionally added to the reaction solution set in a range of 1.0 to 3.2 at a molar ratio to nickel.

7 . A manufacturing method of nickel powder comprising a crystallization process to obtain nickel crystallization powder by precipitating nickel by a reduction reaction in a reaction solution including at least water-soluble nickel salt, metal salt of metal that is nobler than nickel, hydrazine as a reducing agent, alkali metal hydroxide as a pH adjusting agent, and water;
the reaction solution prepared by mixing a nickel salt solution including the water-soluble nickel salt and the metal salt of metal that is nobler than nickel with a reducing agent solution including the hydrazine but not including the alkali metal hydroxide, and then adding an alkali metal hydroxide solution including the alkali metal hydroxide thereto; the hydrazine additionally added to the reaction solution after a reduction reaction initiates in the reaction solution; and an amount of initial hydrazine that is hydrazine among the hydrazine being formulated in the reducing agent solution set in a range of 0.05 to 1.0 at a molar ratio to nickel; further, the amount of additional hydrazine among the hydrazine being additionally added to the reaction solution set in a range of 1.0 to 3.2 at a molar ratio to nickel.

8 . The manufacturing method of nickel powder according to claim 6 , wherein the additional hydrazine is additionally added to the reaction solution over multiple times.

9 . The manufacturing method of nickel powder according to claim 6 , wherein the additional hydrazine is additionally added by dripping continuously.

10 . The manufacturing method of nickel powder according to claim 9 , wherein the dripping speed is in a range of 0.8/h to 9.6/h at a molar ratio to nickel.

11 . The manufacturing method of nickel powder according to claim 6 , wherein, as the metal salt of metal that is nobler than nickel, at least any one of a copper salt, and one or more noble metal salts selected from gold salt, silver salt, platinum salt, palladium salt, rhodium salt, and iridium salt is used.

12 . The manufacturing method of nickel powder according to claim 11 , wherein the copper salt and the noble metal salt are concurrently used, and a molar ratio of the noble metal salt to the copper salt is within a range of 0.01 to 5.0.

13 . The manufacturing method of nickel powder according to claim 6 , wherein, purified hydrazine where organic impurities included in hydrazine have been removed is used as the hydrazine.

14 . The manufacturing method of nickel powder according to claim 6 , wherein any one of sodium hydroxide, potassium hydroxide, and a mixture of these is used as the alkali metal hydroxide.

15 . The manufacturing method of nickel powder according to claim 6 , wherein a complexing agent is included to at least either of the nickel salt solution and the reducing agent solution.

16 . The manufacturing method of nickel powder according to claim 15 , wherein, as the complexing agent, one or more selected from hydroxy carboxylic acid, hydroxy carboxylic acid salt, hydroxy carboxylic acid derivatives, carboxylic acid, carboxylic acid salt, and carboxylic acid derivatives is used, and an amount of the complexing agent is within a range of 0.05 to 1.2 in a molar ratio to nickel.

17 . The manufacturing method of nickel powder according to claim 6 , wherein a reaction initiation temperature that is a temperature of the reaction solution at an initiation of the crystallization reaction is in a range of 60° C. to 95° C.

18 . The manufacturing method of nickel powder according to claim 6 , wherein a sulfur coating agent is added to nickel powder slurry that is an aqueous solution including the nickel powder obtained in the crystallization to obtain nickel powder having a surface modified with sulfur.

19 . The manufacturing method of nickel powder according to claim 18 , wherein, water-soluble sulfur compounds including at least either of mercapto group and disulfide group is used.

20 . An internal electrode paste comprising nickel powder and organic solvent, wherein the nickel powder is constructed by the nickel powder according to claim 1 .

21 . A ceramic electronic components comprising at least an internal electrode, wherein the internal electrode is constructed by a thick film conductor formed with the internal electrode paste according to claim 20 .

22 . The manufacturing method of nickel powder according to claim 7 , wherein the additional hydrazine is additionally added to the reaction solution over multiple times.

23 . The manufacturing method of nickel powder according to claim 7 , wherein the additional hydrazine is additionally added by dripping continuously

24 . The manufacturing method of nickel powder according to claim 7 , wherein, as the metal salt of metal that is nobler than nickel, at least any one of a copper salt, and one or more noble metal salts selected from gold salt, silver salt, p

Assignees

• Sumitomo Metal Mining Co
• Murata Manufacturing Co

Inventors

• Ishii Junji
• Murakami Shingo
• Tanaka Hiroyuki
• Kamata Takahiro
• Terao Toshiaki
• Yukinobu Masaya
• Watanabe Yuji
• Tanimitsu Tsutomu
• Kunifusa Yoshiyuki
• Nishiyama Haruo

Classifications

• B22F1/065

  Spherical particles · CPC title

• B22F1/16 Primary

  Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10) · CPC title

• H01B13/00

  Apparatus or processes specially adapted for manufacturing conductors or cables · CPC title

• H01B1/22

  the conductive material comprising metals or alloys · CPC title

• B22F9/24 Primary

  starting from liquid metal compounds, e.g. solutions · CPC title