Method for manufacturing dielectric ceramic powder, and multilayer ceramic capacitor obtained by using the ceramic powder

Inactive Publication Date: 2006-10-05
SAMSUNG ELECTRO MECHANICS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0012] The present invention has been made to solve the foregoing problems of the prior art and it is therefore an object of the present in

Problems solved by technology

This method has the advantage of directly producing spherical crystal BaTiO3 sized about 100 nm but has the disadvantage of difficult design and maintenance of a reactor, and expensive manufacturing cost.
Furthermore, recently, BaTiO3 powder produced by hydrothermal synthesis has revealed significant defects such as oxygen vacancy and barium vacancy, which develop into pores in the case of heat treatment, thus deteriorating properties of BaTiO3 powder.
However this method has drawbacks in that a synthesis device is hard to configure, and alkoxide reagent used as starting material is expensive.
Furthermore, material cost is expensive due to use of alcohol solvent, and complicated process conditions such as synthesis temperature hamper mass productions.
But BaTiO3 manufactured by solid state reaction reportedly does not exhibit uniform particle size distribution compared to BTO manufactured via other methods described above.
However despite dispersion of each element, the acicular shape of barium compounds remains unchanged, lea

Method used

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  • Method for manufacturing dielectric ceramic powder, and multilayer ceramic capacitor obtained by using the ceramic powder
  • Method for manufacturing dielectric ceramic powder, and multilayer ceramic capacitor obtained by using the ceramic powder
  • Method for manufacturing dielectric ceramic powder, and multilayer ceramic capacitor obtained by using the ceramic powder

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example 1

[0070] BaCO3 raw powder having a specific surface area of 20 m2 / g was prepared. Some of BaCO3 raw powder was dispersed into a mixed solution of distilled water and polyacrylic dispersant to manufacture BaCO3 slurry. BaCO3 raw powder was dispersed into the solution to such an extent that the BaCO3 slurry would contain 10 to 60 wt % BaCO3. The slurry was wet-milled for 18 hours via beads mill type equipment that uses zirconia beads with a diameter of 0.3 mm as milling media. During wet-milling, considering a sudden increase in viscosity in accordance with decrease in BaCO3 particle numbers, ammonia was added after 8 hour milling to reduce viscosity. A specific surface area of the wet-milled BaCO3 powder was 31 m2 / g, a significant increase from the initial one, and the particles had almost a spherical shape.

[0071] Field Emission (FE-SEM) picture before and after wet-milling BaCO3 is shown in FIG. 4(a-b). As shown in the aforesaid FIG. 4(a-b), wet-milling changed BaCO3 from acicular po...

example 2

[0075]

TABLE 1Specific surface areaWet-milling of(m2 / g)CalcinationNo.BaCO3BaCO3TiO2CaCO3temp. (° C.)1Not wet-milled202010202Not wet-milled202010403Wet-milled312010204Wet-milled312010405Wet-milled31459606Wet-milled31459907Wet-milled314510208Wet-milled3145309609Wet-milled314530990

[0076] BaCO3 raw powder having a specific surface area of 20 m2 / g was prepared. Some of BaCO3 raw powder was dispersed into a mixed solution of distilled water and polyarcrylic dispersant to produce BaCO3 slurry. BaCO3 powder was dispersed into the solution to such an extent that BaCO3 slurry would contain 10 to 60 wt % BaCO3. The resultant slurry was wet milled for 18 hours via beads mill type equipment using zirconia beads with a diameter of 0.3 mm as milling media. Considering a sudden increase in viscosity in accordance with decrease in BaCO3 particle numbers during a wet-milling process, ammonia was added to reduce viscosity after 8-hour milling. A specific surface area of the wet-milled BaCO3 powder is s...

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Abstract

The invention relates to a method for manufacturing dielectric ceramic powder and a multilayer ceramic capacitor using the ceramic powder. According to the invention, BaCO3 powder is dispersed into a solution of solvent and dispersant to prepare BaCO3 slurry and then the resultant BaCO3 slurry is wet-milled. Also, TiO2 powder slurry is mixed into the wet-milled BaCO3 slurry to form mixed slurry and then the mixed slurry is dried into mixed powder. Finally, the dried mixed powder is calcined to produce BaTiO3 powder.

Description

CLAIM OF PRIORITY [0001] This application claims the benefit of Korean Patent Application No. 2005-25891 filed on Mar. 29, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a method for manufacturing dielectric ceramic powder. More particularly, the present invention relates to a method for manufacturing dielectric ceramic powder by using wet-milled, BaCO3 as raw powder to prepare raw ceramic powder via solid state reaction, thereby ensuring fine particle size and uniform particle size distribution, and a multilayer ceramic capacitor made from the ceramic powder. [0004] 2. Description of the Related Art [0005] The information society of the 21st century has seen an increasing trend of digitalization, high-performance and high-reliability and multimedia in products such as electronic appliances, PC, HHP which chiefly utilize...

Claims

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Application Information

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IPC IPC(8): H01G4/06
CPCB82Y30/00H01G4/1227C01P2004/04C01P2004/62C01P2004/64C01P2006/12C04B35/4682C04B35/6261C04B35/62625C04B35/62675C04B2235/3208C04B2235/3215C04B2235/3225C04B2235/3239C04B2235/3263C04B2235/528C04B2235/5409C04B2235/5436C04B2235/5463C04B2235/761C04B2235/765C01G23/006B41J2/165B41J2/175B41J2002/16502
Inventor RYU, SUNG SOOPARK, SEON CHEOLLEE, SANG PYOSINN, DONG SOOKLEE, SANG KYUNYOON, DANG HYOK
Owner SAMSUNG ELECTRO MECHANICS CO LTD
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