U.S. patent application number 14/323725 was filed with the patent office on 2014-10-30 for method of manufacturing ceramic powder having perovskite structure and ceramic powder having perovskite structure manufactured using the same.
The applicant listed for this patent is SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Hye Young BAEG, Chang Hak CHOI, Kang Heon HUR, Hyung Joon JEON, Jung Hwan KIM, Sang Hoon KWON, Kum Jin PARK.
Application Number | 20140322537 14/323725 |
Document ID | / |
Family ID | 46753520 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140322537 |
Kind Code |
A1 |
CHOI; Chang Hak ; et
al. |
October 30, 2014 |
METHOD OF MANUFACTURING CERAMIC POWDER HAVING PEROVSKITE STRUCTURE
AND CERAMIC POWDER HAVING PEROVSKITE STRUCTURE MANUFACTURED USING
THE SAME
Abstract
There are provided a method of manufacturing a ceramic powder
having a perovskite structure and a ceramic powder having a
perovskite structure manufactured by the same. The method includes:
mixing a compound of an element corresponding to site A in an
ABO.sub.3 perovskite structure as well as a compound of an element
corresponding to site B in the same structure, with supercritical
water in a continuous mode to form seed crystals; and mixing the
seed crystals in a batch mode to conduct grain growth thereof.
Inventors: |
CHOI; Chang Hak; (Suwon,
KR) ; PARK; Kum Jin; (Suwon, KR) ; HUR; Kang
Heon; (Seongnam, KR) ; BAEG; Hye Young;
(Suwon, KR) ; KIM; Jung Hwan; (Suwon, KR) ;
JEON; Hyung Joon; (Suwon, KR) ; KWON; Sang Hoon;
(Suwon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRO-MECHANICS CO., LTD. |
Suwon-Si |
|
KR |
|
|
Family ID: |
46753520 |
Appl. No.: |
14/323725 |
Filed: |
July 3, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13411037 |
Mar 2, 2012 |
8802050 |
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14323725 |
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Current U.S.
Class: |
428/402 ;
423/593.1 |
Current CPC
Class: |
C04B 35/6264 20130101;
C04B 35/48 20130101; C01P 2006/12 20130101; C04B 2235/761 20130101;
C01P 2004/64 20130101; C04B 2235/5445 20130101; C04B 35/4682
20130101; C01P 2002/77 20130101; C01P 2002/34 20130101; C04B
2235/5454 20130101; Y10T 428/2982 20150115; Y02P 20/54 20151101;
C01P 2006/40 20130101; Y02P 20/544 20151101; C01P 2004/62 20130101;
B82Y 30/00 20130101; C01P 2004/03 20130101; C01P 2004/04 20130101;
C04B 2235/5409 20130101; C04B 2235/768 20130101; C01G 23/006
20130101; C01G 25/006 20130101 |
Class at
Publication: |
428/402 ;
423/593.1 |
International
Class: |
C04B 35/468 20060101
C04B035/468 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2011 |
KR |
10-2011-0018542 |
Claims
1-12. (canceled)
13. A ceramic powder having an ABO.sub.3 perovskite structure, the
ceramic powder manufactured by: mixing a compound of an element
corresponding to site A of the structure as well as a compound of
an element corresponding to site B of the structure with
supercritical water in a continuous mode to form seed crystals; and
mixing the seed crystals in a batch mode to conduct grain growth
thereof.
14. The ceramic powder of claim 13, wherein the seed crystals have
an average particle diameter ranging from 3 to 20 nm and a crystal
axis ratio (c/a) ranging from 1.001 to 1.004.
15. The ceramic powder of claim 13, wherein the ceramic powder
obtained after the grain growth has an average particle diameter
ranging from 50 to 150 nm and a crystal axis ratio (c/a) ranging
from 1.005 to 1.010.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of Korean Patent
Application No. 10-2011-0018542 filed on Mar. 2, 2011, 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 of manufacturing a
ceramic powder having a perovskite structure and a ceramic powder
having a perovskite structure manufactured by the same and, more
particularly, to a method of manufacturing a ceramic powder having
a perovskite structure with excellent crystalinity and a small
average particle diameter and a ceramic powder having a perovskite
structure manufactured by the same.
[0004] 2. Description of the Related Art
[0005] Since electrical and electronic equipment industries have
recently tended to pursue high performance devices having small,
light weight bodies (or devices reduced in weight, thickness,
length and size), electronic components are required to have a
small size, high performance and low price. Specifically, with the
progress of high speed CPUs and reduction in the weight and size,
as well as the digitalization and high functionalization of
electronic equipment, research and investigation into an embodiment
of a multilayer ceramic capacitor (hereinafter, `MLCC`) having
specific characteristics such as decreased size and thickness, high
capacitance, and low impedance in the range of high frequencies
have also been actively conducted.
[0006] Perovskite powder used as a dielectric layer of an MLCC is
mostly prepared by a solid phase method, co-precipitation, or the
like. However, such methods require a calcination process at a high
temperature and a grinding (pulverization) process, since a
crystalline phase is formed during high temperature calcination,
and may have the disadvantage of non-uniform particle size.
[0007] In recent years, in order to provide high capacity and a
reduction of a size of an MLCC, a decrease in a thickness of a
dielectric layer for constructing the MLCC has been required.
However, in a case in which the dielectric layer has a reduced
thickness, a surface roughness of the dielectric layer is increased
and a ratio of short circuits is also increased when the perovskite
powder has a relatively large particle size, causing insulation
resistance failure.
[0008] Accordingly, extensive studies into the synthesis of powder
using hydrothermal synthesis or hydrolysis of metal alkoxide to
produce perovskite powder having excellent characteristics have
been conducted.
[0009] Although the hydrothermal synthesis has the merit of
enabling direct production of crystalline barium titanate in a
spherical form, it entails problems such as difficulties in the
designing and management of a reaction pipe and high production
costs. Moreover, it has recently been reported that some defects
such as oxygen vacancy and/or barium vacancy are present in barium
titanate particles prepared by hydrothermal synthesis and may be
enlarged to form pores during heat treatment, deteriorating
dielectric properties.
[0010] Meanwhile, barium titanate synthesis using the hydrolysis of
metal alkoxide has advantages such as higher reactivity than
hydrothermal synthesis owing to use of a starting material in a
liquid state, the possibility of synthesis at a relatively low
temperature, or the like. However, in the case in which an alkoxide
reagent is used as a starting material, the material is expensive.
Also, since an alcohol solvent is used, processing conditions such
as a synthesis temperature are relatively complicated, causing
restrictions in the mass-production thereof.
SUMMARY OF THE INVENTION
[0011] An aspect of the present invention provides a method of
manufacturing a ceramic powder having excellent crystallinity and a
perovskite structure with a small average particle diameter, and a
ceramic powder having a perovskite structure manufactured by the
foregoing method.
[0012] According to an aspect of the present invention, there is
provided a method of manufacturing a ceramic powder having an
ABO.sub.3 perovskite structure, the method including: mixing a
compound of an element corresponding to site A of the structure as
well as a compound of an element corresponding to site B of the
structure with supercritical water in a continuous mode to form
seed crystals; and mixing the seed crystals in a batch mode to
conduct grain growth thereof.
[0013] The forming of the seed crystals may be conducted for 5
seconds to 10 minutes.
[0014] The forming of the seed crystals may be conducted at a
temperature ranging from 300 to 500.degree. C. and in an atmosphere
ranging from 50 to 300 atms.
[0015] The forming of the seed crystals may be conducted such that
an average particle diameter of each crystal ranges from 3 to 20 nm
and a crystal axis ratio (c/a) ranges from 1.001 to 1.004.
[0016] The grain growth may be conducted at a temperature ranging
from 150 to 300.degree. C.
[0017] The grain growth may be conducted for 2 to 100 hours.
[0018] The ceramic powder obtained after the grain growth may have
an average particle diameter ranging from 50 to 150 nm and a
crystal axis ratio (c/a) ranging from 1.005 to 1.010.
[0019] The compound of the element corresponding to site A may be
an aqueous material having a salt contained therein.
[0020] The compound of the element corresponding to site B may be
an aqueous material having a salt contained therein.
[0021] The compound of the element corresponding to site B may be a
sol type material.
[0022] The element corresponding to site A may be at least one
selected from a group consisting of Mg, Ca, Sr, Ba and La.
[0023] The element corresponding to site B may be at least one
selected from a group consisting of Ti and Zr.
[0024] According to another aspect of the present invention, there
is provided a ceramic powder having an ABO.sub.3 perovskite
structure, the ceramic powder manufactured by: mixing a compound of
an element corresponding to site A of the structure as well as a
compound of an element corresponding to site B of the structure
with supercritical water in a continuous mode to form seed
crystals; and mixing the seed crystals in a batch mode to conduct
grain growth thereof.
[0025] The seed crystals may have an average particle diameter
ranging from 3 to 20 nm and a crystal axis ratio (c/a) ranging from
1.001 to 1.004.
[0026] The ceramic powder obtained after the grain growth may have
an average particle diameter ranging from 50 to 150 nm and a
crystal axis ratio (c/a) ranging from 1.005 to 1.010.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The above and other aspects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0028] FIG. 1 schematically illustrates the constitution of a
manufacturing apparatus usable for the production of a ceramic
powder having an ABO.sub.3 perovskite structure according to an
exemplary embodiment of the present invention;
[0029] FIGS. 2A and 2B are scanning electron microscope (SEM)
micrographs showing seed crystals according to Comparative Example
and Example 2;
[0030] FIGS. 3A and 3B are SEM micrographs showing final powder
grains according to Comparative Example and Example 2; and
[0031] FIGS. 4A and 4B are scanning transmission electron
microscope (STEM) micrographs showing final powder grains according
to Comparative Example and Example 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0032] The present invention provides a method of manufacturing a
ceramic powder having an ABO.sub.3 perovskite structure and a
ceramic powder having a perovskite structure manufactured by the
foregoing method.
[0033] According to a method of manufacturing a ceramic powder
having an ABO.sub.3 perovskite structure according to an embodiment
of the present invention, seed crystals are formed by a continuous
reaction using supercritical water and such seed crystals may be
subjected to grain growth in a batch type reaction. The ceramic
powder having an ABO.sub.3 perovskite structure according to the
foregoing method may have a reduced average particle diameter and
excellent crystallinity.
[0034] Hereinafter, a method of manufacturing a ceramic powder
having an ABO.sub.3 perovskite structure according to an exemplary
embodiment of the present invention will be described in detail
with reference to the accompanying drawings. Characteristics of a
ceramic powder having an ABO.sub.3 perovskite structure according
to an exemplary embodiment of the present invention by the
manufacturing method of the ceramic powder having an ABO.sub.3
perovskite structure described below may be more clearly
understood.
[0035] Hereinafter, exemplary embodiments of the present invention
will be provided to allow those skilled in the art to which the
present invention pertains to more clearly understand the present
invention. Therefore, the shapes and/or sizes of respective
elements shown in the accompanying drawings may be enlarged for
clarity, and like reference numerals denote elements having
substantially the same configurations or performing similar
functions and actions throughout the drawings. Also, a variety of
modifications, variations and/or alterations of the exemplary
embodiments of the present invention may be possible and the
present invention is not particularly restricted to the following
embodiments.
[0036] FIG. 1 schematically shows a construction of a manufacturing
apparatus useable for the production of a ceramic powder having an
ABO.sub.3 perovskite structure according to an exemplary embodiment
of the present invention.
[0037] According to an embodiment of the present invention, a raw
material used for the formation of a ceramic powder having an
ABO.sub.3 perovskite structure may be supplied from respective raw
feeders 110, 120 and 130.
[0038] In the ABO.sub.3 perovskite structure, a compound of an
element corresponding to site A (the A-site) (hereinafter,
optionally referred to as `an A element raw material) may be
received in a first raw material feeder 110 and delivered into a
reaction pipe through a pump 140 connected to the first raw
material feeder 110.
[0039] The element corresponding to A-site (hereinafter, optionally
referred to as `A element`) may be an alkali-earth metal or
rare-metal element. Without particular limitation, more
particularly, the A element may be, for example, Mg, Ca, Sr, Ba,
La, or the like, and two or more elements may be used.
[0040] The A element raw material may be a salt type material
including the A element. More particularly, if A element is Ba, an
aqueous salt such as barium acetate, barium chloride, barium
hydroxide, or the like may be used. The salt type material may be
received in the first raw material feeder in an aqueous solution
state. Except for barium hydroxide, barium acetate or barium
chloride may be used after neutralization using an alkaline
solution. The alkaline solution may be LiOH, NaOH, KOH, NH.sub.4OH,
Ba(OH).sub.2, or the like.
[0041] The A element raw material may have a concentration ranging
from 0.1 to 2M, without being particularly limited thereto.
[0042] In the ABO.sub.3 perovskite structure, a compound of an
element corresponding to site B (the B-site) (hereinafter,
optionally referred to as `a B element raw material`) may be
received in a second raw material feeder 120 and delivered into a
reaction pipe through the pump 140 connected to the second raw
material feeder 120.
[0043] The element corresponding to the B-site (hereinafter,
optionally referred to as `B element`) may be a transition metal,
for example, Ti, Zr, or the like, without being particularly
limited thereto, and two or more elements may be used.
[0044] The B element raw material may be a salt type material
including the B element. Without being particularly limited, if the
B element is Ti, for example, a titanium salt such as titanium
tetrachloride (TiCl.sub.4) may be used. Alternatively, if the B
element is Zr, a zirconium salt such as zirconium oxychloride
(ZrOCl.sub.2) may be used. The salt type material may be received
in the second raw material feeder in an aqueous solution state. The
B element raw material may have a concentration ranging from 0.05
to 2M, without being particularly limited thereto.
[0045] Alternatively, the B element raw material may be a sol type
material including the B element. Without being particularly
limited, for example, a titanium dioxide sol, a zirconium oxalate
sol, or the like may be used. When the B element is a sol type,
reactivity may be enhanced to thereby enable the production of a
ceramic powder having excellent crystallinity.
[0046] A third raw material feeder 130 may receive distilled water,
and the distilled water maybe delivered to the reaction pipe
through the pump 140 connected to the third raw material feeder
130. The distilled water supplied to the reaction pipe maybe heated
by a first heater 160 to form supercritical water.
[0047] The A element raw material and the B element raw material
delivered from the first and second raw material feeders 110 and
120, respectively, may come into contact with the supercritical
water in the reaction pipe and be mixed in a continuous mode.
`Mixed in a continuous mode` maybe understood as being a process of
mixing these materials while they flow through the reaction pipe.
Hereinafter, a process of mixing the A element raw material and the
B element raw material with the supercritical water in a continuous
mode may be referred to as a continuous reaction.
[0048] When the A element raw material and the B element raw
material are continuously mixed with the supercritical water, seed
crystals are formed.
[0049] The A element raw material and the B element raw material
may be simultaneously mixed with the supercritical water. The A
element raw material and the B element raw material may react at
room temperature and, in this case, seed crystals formed at room
temperature may be a factor in preventing further grain growth.
Accordingly, the A element raw material and the B element raw
material may be mixed together immediately before reacting them
with the supercritical water.
[0050] Under the supercritical water condition, the solubility of
the salt is rapidly reduced, which in turn causes rapid
precipitation of the A and B elements from the A and B element raw
materials, respectively, and considerably increases the potential
(or a tendency) to become a ceramic powder having an ABO.sub.3
perovskite structure. Therefore, the seed crystals of the ceramic
powder having an ABO.sub.3 perovskite structure are rapidly formed,
enabling the formation of seed crystals having high
crystallinity.
[0051] When the supercritical water passes a subcritical region
while being elevated in temperature, seed crystals may be formed in
the subcritical region and subjected to grain growth. In this case,
advantageous features of the supercritical water, that is, a
reduction of defects by the rapid formation of seed crystals, a
synthesis of super-microparticles, or the like, may not be embodied
therein. Therefore, the A element raw material and the B element
raw material may be mixed with the supercritical water in a
supercritical region.
[0052] The foregoing continuous reaction is conducted while flowing
the raw materials through the reaction pipe, and a reaction time is
relatively short and may range from several to several tens of
seconds. The reaction time may be varied depending on a length of
the reaction pipe and/or a flow rate of the raw material. Without
being particularly limited, the reaction time of the continuous
reaction may range from 5 seconds to 10 minutes.
[0053] A temperature of the continuous reaction may be a
supercritical temperature, for example, in the range of 300 to
500.degree. C. Also, the continuous reaction may be conducted in an
atmosphere ranging from 50 to 300 atms.
[0054] Seed crystals formed by the continuous reaction may have an
average particle diameter ranging from 3 to 20 nm. Since the seed
crystals are rapidly formed under supercritical conditions, OH
defects in the seed crystals may be decreased while crystallinity
is increased. A crystal axis ratio (c/a) of the seed crystals may
range from 1.001 to 1.004.
[0055] The seed crystals formed by the continuous reaction may be
introduced into a batch type reactor 210 through the reaction pipe.
The batch type reactor 210 may have an impeller 220 mounted
therein. In the batch type reactor 210, the seed crystals may be
agitated for a long time and may be grown to a predetermined
particle size by grain growth. Hereinafter, a process of mixing the
seed crystals in the batch type reactor for a predetermined period
of time may be referred to as a batch type reaction.
[0056] With regard to a construction in which a reactive solution
flows along to a reaction pipe according to a continuous reaction,
it is difficult to ensure sufficient time for grain growth.
Therefore, according to an embodiment of the present invention, a
reactant obtained from a continuous reaction is introduced into a
batch type reactor and the grain growth of the reactant is
conducted for a predetermined time in the batch type reactor.
[0057] The batch type reactor 210 may have a second heater 230
mounted thereon and a temperature of the batch type reactor may be
controlled by the second heater 230.
[0058] The batch type reaction may be conducted at a temperature
ranging from 150 to 300.degree. C.
[0059] The batch type reaction may be conducted for several hours
in order to reach a predetermined particle size. Without being
particularly limited, a reaction time of the batch type reaction
may range from 2 to 100 hours, for example.
[0060] As described above, after completing the grain growth of the
seed crystals, a ceramic powder having an ABO.sub.3 perovskite
structure may be obtained. The obtained ceramic powder having the
ABO.sub.3 perovskite structure may have an average particle
diameter ranging from 50 to 150 nm. By regulating the reaction time
and/or the reaction temperature of the batch type reaction, an
average particle diameter of a final powder may be controlled.
[0061] According to the foregoing embodiment of the present
invention, a final powder maybe formed by conducting the grain
growth of seed crystals having excellent crystallinity, therefore,
a ceramic powder having high crystallinity may be manufactured
without limitation on particle size. Without being particularly
limited, for example, a crystal axis ratio (c/a) of the final
powder may range from 1.005 to 1.010. More preferably, a crystal
axis ratio (c/a) of the final powder ranges from 1.0075 to
1.010.
[0062] After completing the batch type reaction, a precipitate
solution is subjected to filtration, followed by washing and
drying, thereby resulting in a ceramic powder having a perovskite
structure.
[0063] In general, when a ceramic powder having a perovskite
structure becomes microfine particles, the crystallinity thereof is
decreased. However, according to an embodiment of the present
invention, a ceramic powder having a perovskite structure with
excellent crystallinity may be obtained while becoming microfine
particles.
[0064] The ceramic powder according to an embodiment of the present
invention is manufactured by forming seed crystals through a
continuous reaction then conducting grain growth of the formed seed
crystals through a batch type reaction. Each of the seed crystals
may have an average particle diameter ranging form 3 to 20 nm and a
crystal axis ratio (c/a) ranging from 1.001 to 1.004. An average
particle diameter of a final powder obtained after the grain growth
through the batch type reaction may range from 50 to 150 nm and a
crystal axis ratio (c/a) thereof may range from 1.005 to 1.010.
[0065] The types or kinds of the ceramic powder having the
ABO.sub.3 perovskite structure according to an embodiment of the
present invention may be varied, depending on the A element raw
material and the B element raw material, without particular
limitation. For example, the ceramic powder may be BaTiO.sub.3,
(BaCa)TiO.sub.3, (BaCa)(TiZr)O.sub.3, Ba(TiZr)O.sub.3, CaTiO.sub.3,
Ca(TiZr)O.sub.3, or the like.
[0066] The ceramic powder having the ABO.sub.3 perovskite structure
manufactured by an embodiment of the present invention may be used
as a dielectric layer of an MLCC. Since the ceramic powder having
the ABO.sub.3 perovskite structure according to the embodiment of
the present invention has a small average particle diameter and
exhibits excellent crystallinity, the ceramic powder may form a
thin dielectric layer. Accordingly, the surface roughness of the
dielectric layer is decreased, thereby reducing short occurrence
while enhancing electrical properties such as insulation
resistance, or the like.
EXAMPLE
[0067] Hereinafter, preferred embodiments of the present invention
will be described in detail with reference to the following
examples and comparative examples. However, these embodiments are
proposed only to provide a more concrete understanding of the
present invention, and the present invention is not particularly
limited thereto.
Examples 1 and 2
[0068] After storing a barium hydroxide solution having a
concentration of 0.1M and a TiO.sub.2 sol in respective feeders,
these materials were introduced into a reaction pipe through a pump
and mixed with supercritical water in the reaction pipe to form
seed crystals. The above continuous reaction was conducted at
351.degree. C. and 263 atms (Example 1) and at 400.degree. C. and
232 atms (Example 2). Next, the formed seed crystals were reacted
in a batch type reactor for 24 hours, thereby producing a final
BaTiO.sub.3 powder having a particle diameter of 80 nm.
COMPARATIVE EXAMPLE
[0069] A barium hydroxide solution having a concentration of 0.1M
and a TiO.sub.2 sol were mixed with distilled water at 95.degree.
C. and under 1 atm to form seed crystals. Next, the formed seed
crystals were reacted in a batch type reactor for 24 hours, thereby
producing a final BaTiO.sub.3 powder having a particle diameter of
80 nm.
[0070] Characteristics of the seed crystals and the final
BaTiO.sub.3 powder grains according to the foregoing examples and
comparative Example were measured and the measured results are
shown in TABLE 1.
TABLE-US-00001 TABLE 1 Comparative Example 1 Example 2 Example Seed
Specific surface 34 34 28 crystal area (m.sup.2/g) I [111]/I [200]*
0.937 1.024 0.880 Lattice constant (.ANG.) 4.011 4.0062 4.0327 c/a
1.001 1.002 1.000 Final Specific surface 12.3 12.2 12.1 powder area
(m.sup.2/g) c/a 1.0080 1.0082 1.0073 *I [111]/I [200] denotes XRD
diffraction pattern ratio
[0071] Referring to Table 1, it was found that the seed crystals
according to Examples 1 and 2 were synthesized under supercritical
conditions, thus having very high crystallinity, compared to a size
of the crystal. It was also found that, when such seed crystals
were grown to be a powder having a particle diameter of 80 nm by
grain growth, the final powder grains also had high crystallinity.
On the other hand, it was found that the seed crystals in
Comparative Example had a relatively high lattice constant (that
is, a strong bond in lattice), leading to reduced
crystallinity.
[0072] FIGS. 2A and 2B are SEM micrographs showing the seed
crystals according to Comparative Example (FIG. 2A) and Example 2
(FIG. 2B), while FIGS. 3A and 3B are SEM micrographs showing the
final powder grains according to Comparative Example (FIG. 3A) and
Example 2 (FIG. 3B).
[0073] FIGS. 4A and 4B are STEM micrographs showing the final
powder grains according to Comparative Example and Example 2, as
described above.
[0074] Referring to FIG. 4A, the final powder according to the
Comparative Example has a number of pores while FIG. 4B shows that
the final powder according to Example 2 has no pores.
[0075] As set forth above, according to exemplary embodiments of
the present invention, seed crystals may be formed under a
supercritical water condition. Under such a supercritical water
condition, a ceramic powder having an ABO.sub.3 perovskite
structure is rapidly formed into seed crystals, enabling the
formation of seed crystals having high crystallinity. The seed
crystals having high crystallinity may slowly undergo grain growth
by a batch type reaction.
[0076] According to an embodiment of the present invention, seed
crystals having excellent crystallinity are subjected to grain
growth to produce a final power, to thereby manufacture a ceramic
powder having high crystallinity without particular limitation in a
particle size of the final powder.
[0077] When a ceramic powder having an ABO.sub.3 perovskite
structure manufactured by the method according to an embodiment of
the present invention is used as a dielectric layer of an MLCC, the
dielectric layer formed thereby may have reduced thickness and
electrical properties of the MLCC may be enhanced.
[0078] The present invention is not particularly limited by the
foregoing embodiments and the accompanying drawings, but defined by
the appended claims. Accordingly, it will be apparent to those
skilled in the art that various substitutions, modifications and
variations can be made without departing from the spirit and scope
of the invention as defined by the appended claims, and may be
included in the scope of the present invention.
* * * * *