KR100390468B1 - Process for Preparing Nanocrystalline Dielectric Ceramics - Google Patents

Process for Preparing Nanocrystalline Dielectric Ceramics Download PDF

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KR100390468B1
KR100390468B1 KR10-2000-0054228A KR20000054228A KR100390468B1 KR 100390468 B1 KR100390468 B1 KR 100390468B1 KR 20000054228 A KR20000054228 A KR 20000054228A KR 100390468 B1 KR100390468 B1 KR 100390468B1
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oxygen
batio
sintering
powder
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김병국
김진상
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한국과학기술연구원
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    • C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
    • C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
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    • H01G4/06—Solid dielectrics
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    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3231—Refractory metal oxides, their mixed metal oxides, or oxide-forming salts thereof
    • C04B2235/3232—Titanium oxides or titanates, e.g. rutile or anatase
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    • H01B3/12—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances ceramics

Abstract

본 발명은 희토류 원소 및 Cu2O가 첨가된 초미립 BaTiO3계 유전체 세라믹스의 제조 방법에 관한 것이다. 본 발명의 초미립 유전체 세라믹스의 제조 방법은 통상의 고상 반응법에 따라 BaTiO3분말에 RE2O3(RE는 La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er 및 Yb로 이루어지는 군 중에서 선택되는 1종 이상의 희토류 원소이다) 분말 및 Cu2O 분말을 첨가하여 혼합 분말을 제조한 후, 이를 산소 분위기 하에서 소결시키는 것을 특징으로 한다. 본 발명에 따르면, BaTiO3에 희토류 원소 및 Cu2O를 첨가하고 소결 공정을 산소 분위기로 제어함으로써 저온에서 고밀도이며 초미립인 BaTiO3계 유전체 세라믹스를 얻을 수 있다.The present invention relates to a method for producing ultrafine BaTiO 3 based dielectric ceramics to which rare earth elements and Cu 2 O are added. According to the conventional solid-phase reaction method, the method of preparing the ultrafine dielectric ceramics of the present invention is performed on BaTiO 3 powders with RE 2 O 3 (RE is La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb). At least one rare earth element selected from the group consisting of) powder and Cu 2 O powder is added to prepare a mixed powder, it is characterized by sintering in an oxygen atmosphere. According to the present invention, by adding a rare earth element and Cu 2 O to BaTiO 3 and controlling the sintering process in an oxygen atmosphere, a high density, ultrafine BaTiO 3 based dielectric ceramic can be obtained at low temperature.

Description

초미립 유전체 세라믹스의 제조 방법{Process for Preparing Nanocrystalline Dielectric Ceramics}Process for Preparing Nanocrystalline Dielectric Ceramics

본 발명은 초미립 유전체 세라믹스의 제조 방법에 관한 것으로, 보다 구체적으로는, BaTiO3에 Cu2O 및 희토류 금속 산화물을 첨가하고 소결 공정을 산소 분위기로 제어함으로써 저온에서 고밀도이며 초미립인 티탄산바륨유전체 세라믹스를 제조하는 방법에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing ultrafine dielectric ceramics, and more particularly, to a high density and ultrafine barium titanate dielectric at low temperatures by adding Cu 2 O and rare earth metal oxides to BaTiO 3 and controlling the sintering process to an oxygen atmosphere. A method for producing ceramics.

적층형 세라믹 콘덴서 (Multi-Layer Ceramics Capacitor)는 작고 가벼운 전자 회로를 구성하는데 있어서 필수적인 수동 부품이다. 현재까지 적층형 세라믹 콘덴서의 제조에 있어서 BaTiO3를 중심으로 한 티탄산 (titanate)계가 주로 사용되어 왔다. 그러나, 이러한 재료들은 일반적으로 1300℃ 이상의 높은 소결 온도에서 제조되므로, Pd, Pt 등과 같은 값비싼 귀금속 내부 전극을 필요로 한다. 이러한 값비싼 전극을 사용하는데 따른 비용을 줄이기 위해서는 Ag, Ag-Pd 등의 값싼 전극을 사용할 수 있는 저온 소성용 유전체 세라믹 조성물이 필요하게 된다.Multi-Layer Ceramics Capacitors are an essential passive component for building small, lightweight electronic circuits. To date, titanate based on BaTiO 3 has been mainly used in the manufacture of multilayer ceramic capacitors. However, these materials are generally manufactured at high sintering temperatures of 1300 ° C. or higher, requiring expensive precious metal internal electrodes such as Pd, Pt and the like. In order to reduce the cost of using such an expensive electrode, there is a need for a low-temperature baking dielectric ceramic composition that can use a cheap electrode such as Ag, Ag-Pd.

한편, 최근 각종 전자 기기의 경박단소화 및 전자 회로의 고집적화에 의한 부품의 소형화 추세에 따라 적층형 세라믹 콘덴서 역시 초소형 소자로 개발할 필요성이 급격히 대두되고 있다. 초소형의 적층형 세라믹 콘덴서를 제조하기 위해서는 소결 후 초미립을 유지할 수 있는 유전체 세라믹 조성물의 개발이 선결되어야 한다. 즉, 저온 소성이 가능하면서도 소성 후 초미립인 유전체 세라믹 조성물이 필요하게 된다.On the other hand, in accordance with the trend of miniaturization of components due to the recent miniaturization of various electronic devices and high integration of electronic circuits, the necessity of developing multilayer ceramic capacitors as micro devices is also rapidly increasing. In order to manufacture a compact multilayer ceramic capacitor, development of a dielectric ceramic composition capable of maintaining ultrafine particles after sintering should be made in advance. That is, a low-temperature firing and ultrafine dielectric ceramic composition is required after firing.

현재까지 적층형 세라믹 콘덴서의 주원료로 사용되고 있는 BaTiO3계 유전체 세라믹스를 저온 소성이 가능하면서도 소성후 초미립이 유지되게 하기 위해서는 Pb계, Cd계, Bi계, B계, Li계 등의 소결 조제를 첨가하여 소결 온도를 낮춤으로써 입자성장을 억제시키는 시도가 이루어져 왔다 (참조: 日本 特許 公開 平5-120915호, 同 平1-192762호). 그러나 이들 소결 조제는 모두 유독성을 가지며, 환경 친화적이지 않으며, 유전체 소지와 반응할 뿐만 아니라 수계에서 용매로 사용되는 물과의 반응하는 등의 문제점을 안고 있다. 이와 같은 문제점을 해결하기 위해서는 환경 친화적이며 화학적으로 안정한 저온 소성용 초미립 BaTiO3계 유전체 세라믹 조성물이 필요하게 된다.Sintering aids such as Pb-based, Cd-based, Bi-based, B-based, Li-based, etc. are added to keep BaTiO 3 -based dielectric ceramics, which have been used as a main raw material of multilayer ceramic capacitors, at low temperature and maintain ultra-fine after firing. Attempts have been made to suppress particle growth by lowering the sintering temperature (cf. Japanese Patent No. Hei 5-120915, Hei 1-92762). However, all of these sintering aids are toxic, not environmentally friendly, and have problems such as not only reacting with dielectric materials, but also reacting with water used as a solvent in water systems. In order to solve such a problem, an environmentally friendly and chemically stable ultrafine BaTiO 3 based dielectric ceramic composition for low temperature firing is required.

환경 친화적이고 화학적으로 안정하며 값싼 Cu를 소결조제로 첨가하는 저온 소성용 BaTiO3계 유전체 세라믹 조성물이 제안되었다. (참조: 日本特許公開公報 平8-203702호, 한국특허공보 94-3970호). 이는 Cu의 첨가에 따른 액상 소결로, 소결이 촉진되기 때문으로 이해되고 있다. 그러나 위와 같이 Cu가 첨가된 저온 소성용 BaTiO3계 유전체 세라믹 조성물에서도 1 ㎛ 이하의 평균 입경은 얻을 수 없다는단점으로 인하여 실제 초소형의 적층형 세라믹 콘덴서의 제조에는 사용되지 못하고 있다.An environmentally friendly, chemically stable BaTiO 3 based dielectric ceramic composition for low temperature firing has been proposed that adds inexpensive Cu as a sintering aid. (Reference: Japanese Patent No. Hei 8-203702, Korean Patent Publication 94-3970). This is understood because the liquid phase sintering furnace with the addition of Cu promotes sintering. However, even in the low-temperature baking BaTiO 3 -based dielectric ceramic composition added with Cu as described above, an average particle diameter of 1 μm or less cannot be obtained, and thus, it has not been used in the manufacture of ultra-small multilayer ceramic capacitors.

이러한 문제점을 해결하기 위하여 BaTiO3에 소결 온도에서 액상을 형성하여 치밀화를 촉진시키는 Cu의 1가 산화물 Cu2O 및 희토류 원소를 동시에 첨가한 저온 소성용 초미립 유전체 세라믹 조성물이 본 발명자들에 의하여 제안된 바 있다 (한국특허출원 제99-47982호 ). 그러나 이 조성물은 평균 입경이 0.2 ㎛ 이하일 때에 5.5 ± 0.3 g/cm3의 소결 밀도밖에 얻을 수 없어 적층형 세라믹 콘덴서로 사용되는 데에 충분한 기계적 강도 및 고유전율은 얻기 힘들다는 문제점이 있다.In order to solve this problem, the present inventors propose an ultrafine dielectric ceramic composition for low-temperature firing, which simultaneously adds Cu monovalent oxide Cu 2 O and rare earth elements to form a liquid phase at BaTiO 3 to promote densification by forming a liquid phase. (Korean Patent Application No. 99-47982). However, this composition has a problem that when the average particle diameter is 0.2 μm or less, only a sintered density of 5.5 ± 0.3 g / cm 3 can be obtained, and thus sufficient mechanical strength and high dielectric constant for use as a multilayer ceramic capacitor are difficult to obtain.

따라서, 본 발명은 상기한 한국특허출원 제 99-47982호의 개량에 관한 것으로, 그 목적은, BaTiO3에 환경 친화적이고 화학적으로 안정한 희토류 원소 및 Cu의 1가 산화물 Cu2O를 동시에 첨가하여 소결공정을 개선함으로써, 저온에서 고밀도이면서도 초미립인 BaTiO3계 유전체 세라믹스를 제조하는 방법을 제공하는 데 있다.Accordingly, the present invention relates to the improvement of the above-described Korean Patent Application No. 99-47982, the object of which is the sintering process by simultaneously adding environmentally friendly and chemically stable rare earth element and Cu monovalent oxide Cu 2 O to BaTiO 3 The present invention provides a method for manufacturing BaTiO 3 -based dielectric ceramics having high density and ultrafine grain at low temperature.

이러한 목적을 달성하기 위하여, 본 발명에 따르면, 고순도의 BaTiO3분말과 Cu2O 분말 및 RE2O3분말을 정량으로 칭량한 다음 볼밀링하여 BaTiO3+ xCu2O + yRE2O3(여기서, 0.00 < x ≤ 0.05이고, 0.00 < y ≤ 0.05이고, RE는 La, Pr, Nd,Sm, Eu, Gd, Tb, Dy, Ho, Er 및 Yb로 이루어지는 군 중에서 선택되는 1종 이상의 희토류 원소이다) 혼합 슬러리를 얻는 단계, 상기 슬러리를 하소하는 단계, 상기 BaTiO3+ xCu2O + yRE2O3하소분말을 성형하는 단계, 및 얻어진 성형체를 산소 분위기 하에서 소결하는 단계를 포함하는 초미립 유전체 세라믹스의 제조 방법이 제공된다.In order to achieve this object, according to the present invention, BaTiO 3 + xCu 2 O + yRE 2 O 3 (wherein high-purity BaTiO 3 powder, Cu 2 O powder and RE 2 O 3 powder are quantitatively weighed and then ball milled) , 0.00 <x ≤ 0.05, 0.00 <y ≤ 0.05, RE is at least one rare earth element selected from the group consisting of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb ) Obtaining a mixed slurry, calcining the slurry, molding the BaTiO 3 + xCu 2 O + yRE 2 O 3 calcined powder, and sintering the obtained molded body under an oxygen atmosphere. A method for producing is provided.

이하, 본 발명에 따른 초미립 유전체 세라믹스 제조 방법을 상세히 설명한다.Hereinafter, a method of manufacturing ultrafine dielectric ceramics according to the present invention will be described in detail.

본 발명의 방법에 따라 초미립 유전체 세라믹스를 제조하기 위한 출발 원료로는 BaTiO3분말과 Cu2O 분말 및 RE2O3(RE는 La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er 및 Yb로 이루어진 군 중에서 선택되는 1종 이상의 희토류 원소이다) 분말을 사용하며, 순도 약 99.9% 이상의 고순도의 것을 사용하는 것이 좋다.Starting materials for producing ultrafine dielectric ceramics according to the method of the present invention include BaTiO 3 powder, Cu 2 O powder and RE 2 O 3 (RE is La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, At least one rare earth element selected from the group consisting of Ho, Er, and Yb), and a high purity of at least about 99.9%.

먼저, 고상 반응법에 따라 BaTiO3분말과 Cu2O 분말 및 RE2O3분말을 각각 최종적으로 얻고자 하는 BaTiO3+ xCu2O + yRE2O3유전체 세라믹의 조성대로 칭량한 후, 에틸알콜과 지르코니아볼을 사용하여 습식 혼합하여 슬러리를 제조한다. 혼합된 슬러리는 건조한 후 소결온도 이하의 약 900∼1100℃의 공기 분위기하에서 하소시킨다.First, the BaTiO 3 powder, Cu 2 O powder, and RE 2 O 3 powder are finally weighed according to the composition of BaTiO 3 + xCu 2 O + yRE 2 O 3 dielectric ceramics, which are to be finally obtained according to the solid phase reaction method. Wet mixing using and zirconia ball to prepare a slurry. The mixed slurry is dried and then calcined in an air atmosphere at about 900 to 1100 ° C. below the sintering temperature.

이와 같이 준비된 BaTiO3+ xCu2O + yRE2O3하소 분말을 가압 성형에 이은 정수압 성형에 의해 성형한 후, 산소 분위기 하에서 상온으로부터 약 360℃/hr의 속도로 1100℃까지 승온시킴으로써 소결한다.The BaTiO 3 + xCu 2 O + yRE 2 O 3 calcined powder thus prepared is molded by press molding followed by hydrostatic molding, and then sintered by raising the temperature to 1100 ° C. at a rate of about 360 ° C./hr from normal temperature in an oxygen atmosphere.

본 발명에서는 산소분위기에서 소결을 수행함으로써 고밀도 초미립의 BaTiO3계 유전체 세라믹스를 제조할 수 있다. 산소분위기하의 소결에 의해서 소결체의 입자성장에 필요한 산소이온 공공의 농도는 감소하는 반면 치밀화에 필요한 Ba 이온 공공의 농도가 증가하게 된다.In the present invention, the high-density ultrafine BaTiO 3 -based dielectric ceramics can be manufactured by performing sintering in an oxygen atmosphere. By sintering under an oxygen atmosphere, the concentration of oxygen ions vacancies necessary for grain growth of the sintered compact is reduced while the concentration of Ba ion vacancy necessary for densification is increased.

소결시 산소분위기를 만들어 주기 위한 산소의 유량은 소결반응로의 부피를 기준으로 1배 이상, 바람직하기로는 3.2배 이상으로 한다. 산소의 유량이 1배 미만으로 되면 공기분위기의 소결과 큰 차이가 없어 산소이온 공공의 농도감소에 실질적인 기여를 기대하기 어렵다. 또한 본 발명자들의 연구결과에 의하면 산소의 유량이 3.2배에서 소결체의 조직이 초미립화되며 그 이상의 유량에서는 큰 변화가 없었다.The flow rate of oxygen to make the oxygen atmosphere during sintering is one or more times, preferably 3.2 times or more, based on the volume of the sintering reactor. If the flow rate of oxygen is less than 1 times, there is no big difference from the sintering of the air atmosphere, and it is difficult to expect a substantial contribution to the concentration reduction of the oxygen ion vacancy. In addition, according to the results of the present inventors, the structure of the sintered body is ultra-fine when the flow rate of oxygen is 3.2 times, and there is no big change in the flow rate above.

상기 본 발명의 방법에 따라 제조된 BaTiO3계 유전체 세라믹스는 평균입경이 약 120 ∼ 90 nm이고, 소결 밀도가 약 5.3 ∼ 5.9 g/cm3인 고밀도 초미립의 유전체 세라믹스이다.BaTiO 3 -based dielectric ceramics produced according to the method of the present invention is a high density ultrafine dielectric ceramic having an average particle diameter of about 120 to 90 nm and a sintered density of about 5.3 to 5.9 g / cm 3 .

이하, 실시예에 의해 본 발명을 더욱 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.

<실시예 1∼36><Examples 1 to 36>

먼저, 순도 약 99.9%의 BaTiO3분말과 Cu2O 분말 및 La2O3분말을 하기 표 1에 기재된 조성대로 칭량한 후, 에틸알콜과 지르코니아 볼을 사용하여 약 36시간 동안 습식 혼합하였다. 혼합된 슬러리를 건조한 후 공기 분위기 하에 약 1000℃에서 약 2시간 동안 하소하였다.First, BaTiO 3 powder, Cu 2 O powder, and La 2 O 3 powder having a purity of about 99.9% were weighed according to the composition shown in Table 1, followed by wet mixing for about 36 hours using ethyl alcohol and zirconia balls. The mixed slurry was dried and then calcined at about 1000 ° C. for about 2 hours under an air atmosphere.

이와 같이 준비된 BaTiO3+ xCu2O + yLa2O3(여기서, x = 0.03이고, 0.00 < y ≤ 0.05이다) 분말을 지름 10 ㎜의 주형에서 1 톤/㎠의 압력으로 일축 가압 성형한 후, 다시 3 톤/㎠의 압력으로 정수압 성형하였다. 얻어진 성형체를 지름 6㎝의 알루미나 튜브내에서 상온으로부터 약 360℃/hr로 1100℃까지 승온시킴으로써 소결시켰다. 이 때의 소결 분위기는 하기 표 1에 기재된 바와 같이 질소, 공기 또는 산소 각 1기압으로 하였으며, 각 가스의 순도는 약 99.9% 이상이고, 그 유량은 300 ∼ 1500 cm3/분 범위 내에서 조절하였다.The BaTiO 3 + xCu 2 O + yLa 2 O 3 (where x = 0.03 and 0.00 <y ≤ 0.05) powder thus prepared was uniaxially press-molded at a pressure of 1 ton / cm 2 in a mold having a diameter of 10 mm, Again, hydrostatic pressure molding was carried out at a pressure of 3 tons / cm 2. The obtained molded object was sintered by raising the temperature to 1100 ° C. at about 360 ° C./hr from normal temperature in an alumina tube having a diameter of 6 cm. The sintering atmosphere at this time was as nitrogen, air or oxygen at 1 atm as shown in Table 1 below, the purity of each gas was about 99.9% or more, and the flow rate was adjusted within the range of 300 to 1500 cm 3 / min. .

소결한 후 최종적인 시편의 두께가 1 ㎜가 되도록 SiC 연마지 (#1000)를 이용하여 연마하였다. 연마 후, 은 페이스트를 시편의 양쪽 면에 바르고 약 600℃에서 약 10분간 열처리하여 전극을 형성하였다. 얻어진 시편의 유전 특성은 LCR meter (Hewlett Packard사 제품, 모델명 4263B)를 사용하여 1.0 Vrms, 1 ㎑에서 측정하였다.After sintering, polishing was performed using SiC abrasive paper (# 1000) so that the final specimen thickness was 1 mm. After polishing, silver paste was applied to both sides of the specimen and heat treated at about 600 ° C. for about 10 minutes to form electrodes. Dielectric properties of the obtained specimens were measured at 1.0 V rms , 1 Hz using an LCR meter (model name 4263B manufactured by Hewlett Packard).

이 후, 시편 양쪽 면의 전극을 모두 제거한 후 소결 밀도를 측정하고, SiC 연마지 (#2000)와 다이아몬드 페이스트 (9, 3, 1 ㎛)으로 한쪽 면을 연마하여 주사전자현미경 (Hitachi사 제품, S-4200)으로 소결체의 평균 입경을 측정하였다.Subsequently, after removing all electrodes on both sides of the specimen, the sintered density was measured, and one side was polished with SiC abrasive paper (# 2000) and diamond paste (9, 3, 1 μm), followed by scanning electron microscope (manufactured by Hitachi, S-4200), the average particle diameter of the sintered compact was measured.

그 결과를 하기 표 1에 나타내었다.The results are shown in Table 1 below.

BaTiO3+ xCu2O + yLa2O3유전체 세라믹스의 유전 특성 및 소결 특성.Dielectric and Sintering Properties of BaTiO 3 + xCu 2 O + yLa 2 O 3 Dielectric Ceramics. No.No. yy 소결 분위기Sintering atmosphere 가스 유량(cm3/min)Gas flow rate (cm 3 / min) 유전 상수Dielectric constant 평균 입경(㎚)Average particle diameter (nm) 소결 밀도(cm3/min)Sintered Density (cm 3 / min) 1One 00 공기air 300300 30003000 200200 5.95.9 22 0.010.01 질소nitrogen 300300 26802680 190190 5.15.1 33 0.010.01 공기air 300300 24902490 150150 5.75.7 44 0.010.01 산소Oxygen 300300 19401940 130130 5.75.7 55 0.010.01 산소Oxygen 600600 20302030 130130 5.85.8 66 0.010.01 산소Oxygen 900900 18601860 120120 5.95.9 77 0.010.01 산소Oxygen 12001200 17101710 120120 5.95.9 88 0.010.01 산소Oxygen 15001500 17801780 120120 5.95.9 99 0.020.02 질소nitrogen 300300 23402340 190190 5.05.0 1010 0.020.02 공기air 300300 20302030 130130 5.65.6 1111 0.020.02 산소Oxygen 300300 19401940 120120 5.65.6 1212 0.020.02 산소Oxygen 600600 17501750 120120 5.75.7 1313 0.020.02 산소Oxygen 900900 17001700 110110 5.85.8 1414 0.020.02 산소Oxygen 12001200 17801780 110110 5.85.8 1515 0.020.02 산소Oxygen 15001500 17201720 110110 5.85.8 1616 0.030.03 질소nitrogen 300300 22502250 140140 5.85.8 1717 0.030.03 공기air 300300 18401840 110110 5.55.5 1818 0.030.03 산소Oxygen 300300 17401740 110110 5.65.6 1919 0.030.03 산소Oxygen 600600 16501650 100100 5.65.6 2020 0.030.03 산소Oxygen 900900 16101610 100100 5.65.6 2121 0.030.03 산소Oxygen 12001200 15301530 100100 5.65.6 2222 0.030.03 산소Oxygen 15001500 15901590 100100 5.65.6 2323 0.040.04 질소nitrogen 300300 21002100 130130 5.05.0 2424 0.040.04 공기air 300300 17301730 110110 5.25.2 2525 0.040.04 산소Oxygen 300300 16601660 100100 5.25.2 2626 0.040.04 산소Oxygen 600600 15301530 100100 5.35.3 2727 0.040.04 산소Oxygen 900900 14501450 9090 5.45.4 2828 0.040.04 산소Oxygen 12001200 15201520 9090 5.45.4 2929 0.040.04 산소Oxygen 15001500 14101410 9090 5.45.4 3030 0.050.05 질소nitrogen 300300 20202020 130130 4.94.9 3131 0.050.05 공기air 300300 17101710 100100 5.25.2 3232 0.050.05 산소Oxygen 300300 16801680 100100 5.25.2 3333 0.050.05 산소Oxygen 600600 15301530 9090 5.35.3 3434 0.050.05 산소Oxygen 900900 14601460 9090 5.35.3 3535 0.050.05 산소Oxygen 12001200 14301430 9090 5.35.3 3636 0.050.05 산소Oxygen 15001500 14501450 9090 5.45.4 x = 0.03, 소결 온도 = 1100℃x = 0.03, sintering temperature = 1100 ° C

상기 표 1의 결과에서 Cu2O 및 La2O3첨가량이 같을 경우에 질소, 공기, 산소 분위기의 순으로 유전 상수는 다소 작으나 소결 밀도가 높고 평균 입경이 작은 유전체 세라믹스를 얻을 수 있었다. 또, 산소 분위기에서 소결할 경우에 900 cm3/분 이상의 유량에서 가장 고밀도이며 초미립인 BaTiO3계 유전체 세라믹스를 얻을 수 있었다.In the results of Table 1, when the amounts of Cu 2 O and La 2 O 3 were the same, dielectric ceramics having a relatively small dielectric constant but a high sintered density and a small average particle diameter were obtained in the order of nitrogen, air, and oxygen atmosphere. In addition, when sintered in an oxygen atmosphere, the most dense and ultrafine BaTiO 3 dielectric ceramics were obtained at a flow rate of 900 cm 3 / min or more.

이와 같은 BaTiO3의 고밀도 초미립화는 산소 분위기 하에서의 소결로 인하여 입자 성장에 필요한 산소 이온 공공의 농도가 감소하고 치밀화에 필요한 Ba 이온 공공의 농도가 증가하며 900 cm3/분 이상의 유량에서 표면 교환 반응에 필요한 산소 이온이 충분히 공급되는데 기인하는 것으로 보인다. 즉, 산소 분위기 소결에 의하여 입자 성장에 필요한 산소 이온 공공의 농도가 감소하고 치밀화에 필요한 Ba 이온 공공의 농도가 증가됨으로써 질소 및 공기 분위기 소결에 비하여 고밀도이며 초미립인 저온 소성용 BaTiO3계 유전체 세라믹스를 얻을 수 있는 것으로 판단된다.Such high-density ultrafine atomization of BaTiO 3 decreases the concentration of oxygen ion vacancies required for particle growth due to sintering under oxygen atmosphere, increases the concentration of Ba ion vacancies required for densification, and results in surface exchange reaction at a flow rate of 900 cm 3 / min or more. It appears to be due to the sufficient supply of necessary oxygen ions. That is, by the oxygen atmosphere sintering reduces the concentration of oxygen ions public necessary for the grain growth and increasing the concentration of the Ba ion public necessary for densification by being a high density as compared with a nitrogen and air atmosphere sintering ultrafine a low-temperature co-fired BaTiO 3 based dielectric ceramics for It is judged that can be obtained.

<실시예 37∼66><Examples 37-66>

혼합 분말의 조성을 하기 표2와 같이 하고, 산소 분위기 하에서 가스 유량 1200 cm3/분의 조건으로 소결하는 것을 제외하고는 상기 실시예 1∼36의 방법을 반복하고, 그 결과를 표 2에 함께 나타내었다.The compositions of the mixed powder were prepared as shown in Table 2 below, except that the powders were sintered under a gas flow rate of 1200 cm 3 / min under an oxygen atmosphere, and the methods of Examples 1 to 36 were repeated, and the results are shown in Table 2 together. It was.

표 2에서 보는 바와 같이, 희토류 산화물을 다양하게 변화시키고 가스유량을 900㎤/분 이상인 1200㎤/분으로 한 경우에도 표 1에서 얻은 결과와 큰 차이를 나타내지는 않음을 알 수 있다.As shown in Table 2, it can be seen that even when the rare earth oxide is variously changed and the gas flow rate is set to 1200 cm 3 / min, which is 900 cm 3 / min or more, the results obtained in Table 1 do not show a significant difference.

BaTiO3+ xCu2O + yRE2O3유전체 세라믹스의 유전 특성 및 소결 특성.Dielectric and Sintering Properties of BaTiO 3 + xCu 2 O + yRE 2 O 3 Dielectric Ceramics. No.No. xx yy RERE 유전 상수Dielectric constant 평균 입경(㎚)Average particle diameter (nm) 소결 밀도(cm3/min)Sintered Density (cm 3 / min) 3737 0.010.01 0.020.02 LaLa 18301830 120120 5.95.9 3838 0.010.01 0.030.03 LaLa 16801680 110110 5.85.8 3939 0.010.01 0.040.04 LaLa 17201720 110110 5.85.8 4040 0.020.02 0.020.02 LaLa 17901790 120120 5.85.8 4141 0.020.02 0.030.03 LaLa 17801780 110110 5.85.8 4242 0.020.02 0.040.04 LaLa 15401540 100100 5.75.7 4646 0.030.03 0.020.02 PrPr 17301730 110110 5.85.8 4747 0.030.03 0.020.02 NdNd 16601660 110110 5.85.8 4848 0.030.03 0.020.02 EuEu 16801680 100100 5.75.7 4949 0.030.03 0.020.02 DyDy 17001700 110110 5.75.7 5050 0.030.03 0.020.02 YbYb 16101610 110110 5.85.8 5151 0.030.03 0.030.03 PrPr 15801580 100100 5.75.7 5252 0.030.03 0.030.03 NdNd 15201520 100100 5.65.6 5353 0.030.03 0.030.03 EuEu 15501550 100100 5.65.6 5454 0.030.03 0.030.03 DyDy 14301430 9090 5.75.7 5555 0.030.03 0.030.03 YbYb 14101410 100100 5.65.6 5656 0.030.03 0.040.04 PrPr 14001400 9090 5.45.4 5757 0.030.03 0.040.04 NdNd 13501350 100100 5.55.5 5858 0.030.03 0.040.04 EuEu 14201420 9090 5.45.4 5959 0.030.03 0.040.04 DyDy 13101310 9090 5.45.4 6060 0.030.03 0.040.04 YbYb 14001400 9090 5.55.5 6161 0.040.04 0.020.02 LaLa 14701470 9090 5.35.3 6262 0.040.04 0.030.03 LaLa 15201520 100100 5.45.4 6363 0.040.04 0.040.04 LaLa 14801480 9090 5.45.4 6464 0.050.05 0.020.02 LaLa 13601360 9090 5.35.3 6565 0.050.05 0.030.03 LaLa 13301330 9090 5.55.5 6666 0.050.05 0.040.04 LaLa 14101410 9090 5.45.4 소결 온도 = 1100℃, 산소 분위기, 산소 유량 = 1200 cm3/분Sintering temperature = 1100 ° C, oxygen atmosphere, oxygen flow rate = 1200 cm 3 / min

본 발명에 따르면, BaTiO3에 Cu2O 및 희토류 금속 산화물을 첨가하고 소결 공정을 산소 분위기로 제어함으로써 저온에서 고밀도이며 초미립인 유전체 세라믹스를 얻을 수 있다.According to the present invention, by adding Cu 2 O and rare earth metal oxide to BaTiO 3 and controlling the sintering process in an oxygen atmosphere, it is possible to obtain a high density, ultrafine dielectric ceramic at low temperature.

Claims (4)

고순도의 BaTiO3분말과 Cu2O 분말 및 RE2O3분말을 정량으로 칭량한 다음 볼밀링하여 BaTiO3+ xCu2O + yRE2O3로 구성되는 혼합 슬러리를 얻는 단계,Quantitatively weighing high purity BaTiO 3 powder, Cu 2 O powder and RE 2 O 3 powder, and then ball milling to obtain a mixed slurry consisting of BaTiO 3 + xCu 2 O + yRE 2 O 3 , 상기 슬러리를 하소하는 단계,Calcining the slurry, 상기 BaTiO3+ xCu2O + yRE2O3하소분말을 성형하는 단계, 및Molding the BaTiO 3 + xCu 2 O + yRE 2 O 3 calcined powder, and 얻어진 성형체를 산소 분위기 하에서 소결하는 단계를 포함하며, 상기 BaTiO3+ xCu2O + yRE2O3에서 0.00 < x ≤ 0.05이고, 0.00 < y ≤ 0.05이고, RE는 La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er 및 Yb로 이루어지는 군 중에서 선택되는 1종 이상의 희토류 원소인 것을 특징으로 하는 초미립 유전체 세라믹스의 제조방법.Sintering the obtained compact under an oxygen atmosphere, wherein at BaTiO 3 + xCu 2 O + yRE 2 O 3 , 0.00 <x ≦ 0.05, 0.00 <y ≦ 0.05, and RE is La, Pr, Nd, Sm, A method for producing ultrafine dielectric ceramics, characterized in that it is at least one rare earth element selected from the group consisting of Eu, Gd, Tb, Dy, Ho, Er and Yb. 제 1 항에 있어서, 상기 산소분위기를 만들어 주기 위한 산소의 유량은 소결반응로의 부피를 기준으로 1배 이상으로 산소를 공급하는 것을 특징으로하는 초미립 유전체 세라믹스의 제조방법.The method of manufacturing an ultrafine dielectric ceramic according to claim 1, wherein the flow rate of oxygen for making the oxygen atmosphere is to supply oxygen at least one time based on the volume of the sintering reactor. 제 2 항에 있어서, 상기 산소분위기를 만들어 주기 위한 산소의 유량은 소결반응로의 부피를 기준으로 3.2배 이상으로 산소를 공급하는 것을 특징으로하는 초미립 유전체 세라믹스의 제조방법.The method of manufacturing an ultrafine dielectric ceramic according to claim 2, wherein the flow rate of oxygen for making the oxygen atmosphere is to supply oxygen at least 3.2 times based on the volume of the sintering reactor. 제 1 항에 있어서, 상기 하소단계는 900∼1100℃에서 0.5∼2시간 수행하는 것을 특징으로하는 초미립 유전체 세라믹스의 제조방법.The method of claim 1, wherein the calcination step is performed at 900 to 1100 ° C. for 0.5 to 2 hours.
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