KR100875479B1 - Lead-free piezoelectric ceramic composition and its manufacturing method - Google Patents

Lead-free piezoelectric ceramic composition and its manufacturing method Download PDF

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KR100875479B1
KR100875479B1 KR1020070056769A KR20070056769A KR100875479B1 KR 100875479 B1 KR100875479 B1 KR 100875479B1 KR 1020070056769 A KR1020070056769 A KR 1020070056769A KR 20070056769 A KR20070056769 A KR 20070056769A KR 100875479 B1 KR100875479 B1 KR 100875479B1
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lead
ceramic composition
piezoelectric
piezoelectric ceramic
composition
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KR20080108781A (en
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김민수
전소현
정순종
김인성
민복기
송재성
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한국전기연구원
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/85—Piezoelectric or electrostrictive active materials
    • H10N30/853—Ceramic compositions
    • H10N30/8542—Alkali metal based oxides, e.g. lithium, sodium or potassium niobates
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/09—Forming piezoelectric or electrostrictive materials
    • H10N30/093—Forming inorganic materials
    • H10N30/097—Forming inorganic materials by sintering
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors

Abstract

본 발명은 비납계 압전 세라믹스 조성물 및 그의 제조방법에 관한 것으로써, 특히 납(Pb)이 함유되지 않은 우수한 유전특성 및 압전 특성을 가지는 비납계 압전 세라믹스의 조성을 개발하였다. 이를 위해 본 발명은 (NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3의 세라믹스 조성물에 1족 원소 화합물인 Li2CO3와 Na2CO3가 첨가되는 조성으로 우수한 유전 및 압전 특성을 지니는 비납계 압전 세라믹스 조성물을 기술적 특징으로 하며, 또한, 1족 원소 화합물의 첨가량은 0.9 ~ 1.1 mol%이며, 시료를 혼합, 분쇄한 후 건조하여 하소하였고, 이 하소된 시료를 재 하소한 후, 다시 혼합, 분쇄, 건조, 소결의 과정으로 압전 세라믹스 조성물을 제조하는 방법을 그 기술적 특징으로 한다. 이에 따라 우수한 유전 및 압전 특성을 가지는 비납계 압전 세라믹스 조성물을 개발하였으며, 또한, 상기의 비납계 압전 세라믹스 조성물은 압전센서와 압전 세라믹 액추에이터로의 적용이 가능하도록 높은 압전상수와 전기기계결합계수를 가지는 효과가 있다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-lead piezoelectric ceramic composition and a method of manufacturing the same, and in particular, has developed a composition of a non-lead piezoelectric ceramic having excellent dielectric and piezoelectric properties containing no lead (Pb). To this end the invention (Na x K x Li 0 .95- 0 .05) (Nb 0 .95 0 .05 Ta) O 3 in the ceramic composition of the group 1 element compound is Li 2 CO 3 and Na 2 CO 3 is It is characterized by a non-lead piezoelectric ceramic composition having excellent dielectric and piezoelectric properties as a composition to be added, and the amount of the Group 1 element compound is 0.9 to 1.1 mol%, and the sample is mixed, pulverized and dried and calcined. After the calcined sample is calcined again, a method of producing a piezoelectric ceramic composition by a process of mixing, pulverizing, drying and sintering again is the technical feature. Accordingly, a non-lead piezoelectric ceramic composition having excellent dielectric and piezoelectric properties has been developed, and the non-lead piezoelectric ceramic composition has a high piezoelectric constant and an electromechanical coupling coefficient so that it can be applied to piezoelectric sensors and piezoelectric ceramic actuators. It works.

Description

비납계 압전 세라믹스 조성물 및 그 제조방법{Composition and the manufacturing method of lead-free piezoelectric ceramics}Lead-free piezoelectric ceramics composition and a method of manufacturing the same {Composition and the manufacturing method of lead-free piezoelectric ceramics}

도 1 - (NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3의 조성일 때의 각 소결 온도에 따른 미세구조 사진.Figure 1 - (Na x K x Li 0 .95- 0 .05) microstructure picture according to each sintering temperature in joseongil of (Nb 0 .95 0 .05 Ta) O 3.

도 2 a, b, c - 각각 Na/K의 비율과 소결온도에 따른 압전상수(d33), 전기기계결합계수(kp), 유전상수(er)의 변화 그래프.Figure 2 a, b, c-piezoelectric constant (d 33 ), electromechanical coupling coefficient (k p ), dielectric constant (e r ) of the change of the Na / K ratio and the sintering temperature, respectively.

도 3 - (NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3에 Li2CO3를 첨가 하였을 때, 각 소결 온도에 따른 미세구조 사진.Figure 3 - (Na x K 0 .95- x Li 0 .05) (Nb 0 .95 Ta 0 .05) as the addition of Li 2 CO 3 for O 3, microstructures pictures according to each sintering temperature.

도 4 a, b, c - 각각 Na/K의 비율과 소결온도에 따른 압전상수(d33), 전기기계결합계수(kp), 유전상수(er)의 변화 그래프.4 a, b, c-graphs of the piezoelectric constant (d 33 ), the electromechanical coupling coefficient (k p ), and the dielectric constant (e r ) according to Na / K ratio and sintering temperature, respectively.

도 5 -(NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3에 Na2CO3를 첨가 하였을 때, 각 소결 온도에 따른 미세구조 사진.Figure 5 - (Na x K 0 .95- x Li 0 .05) (Nb 0 .95 Ta 0 .05) as the addition of Na 2 CO 3 for O 3, microstructures pictures according to each sintering temperature.

도 6 a, b, c - 각각 Na/K의 비율과 소결온도에 따른 압전상수(d33), 전기기계결합계수(kp), 유전상수(er)의 변화 그래프.6 a, b and c-graphs of the piezoelectric constant (d 33 ), the electromechanical coupling coefficient (k p ), and the dielectric constant (e r ) according to Na / K ratio and sintering temperature, respectively.

본 발명은 비납계(Pb-free) 압전 세라믹스 조성물 및 그 제조방법에 관한 것으로, 특히 우수한 유전 및 압전 특성을 가지는 비납계 압전 세라믹스 및 그의 제조방법에 관한 것이다. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-free piezoelectric ceramic composition and a method of manufacturing the same, and more particularly to a non-lead piezoelectric ceramic having excellent dielectric and piezoelectric properties and a method of manufacturing the same.

일반적으로, PZT는 현재 가장 우수한 압전 특성을 가진 압전 재료로서 많은 응용분야에서 이용되고 있다. PbTiO3와 PbZrO3의 고용체에 있어서 정방정계-삼방정계의 상경계(MPB: Morphotropic Phase Boundary)에서 강한 압전 특성을 가지면서 390℃의 Curie 온도를 가지는 PZT 고용체가 발견됨에 따라, 이 세라믹스를 이용해서 압전효과, 역 압전효과를 이용한 압전 액추에이터, 압전 트랜스듀서, 센서, 레조네이터 등에 적용하는 연구가 활발하게 이루어지고 있다.In general, PZT is currently used in many applications as a piezoelectric material having the best piezoelectric properties. In the solid solution of PbTiO 3 and PbZrO 3 , a PZT solid solution having a Curie temperature of 390 ° C. with strong piezoelectric properties was found in the Morphotropic Phase Boundary (MPB) of the tetragonal system. Research is being actively applied to piezoelectric actuators, piezoelectric transducers, sensors, and resonators using the effects and the reverse piezoelectric effect.

그러나 압전 특성이 우수한 대부분의 세라믹스의 경우 납(Pb)을 포합하는 조성을 가짐으로써, 1000℃ 이상에서는 PbO가 급격히 휘발함으로 인해 조성의 변동이 생겨 재현성이 어려우므로, 이를 방지하기 위해 조성에 과잉으로 PbO를 첨가하여 제조하고 있다. 이는 환경오염을 야기시킴은 물론이요, 또한 가격 경쟁력 측면에도 문제를 가지고 있어 최근에는 비납계 세라믹스의 조성에 대한 많은 연구가 진행되고 있다. However, most ceramics with excellent piezoelectric properties have a composition containing lead (Pb), and PbO is rapidly volatilized at 1000 ° C. or higher, which causes variations in composition, making it difficult to reproduce, thus preventing excessive PbO in the composition. It is prepared by adding. This not only causes environmental pollution, but also has a problem in terms of price competitiveness. Recently, many studies on the composition of lead-free ceramics have been conducted.

비납계 압전 세라믹스 중 (Na0 .5K0 .5)NbO3은 높은 상전이온도, 낮은 항전계, 높은 잔류분극들의 특성을 가지고 있어 납을 기본조성으로 하는 압전 세라믹스를 대체할 수 있는 대표적인 물질중의 하나로 여겨지고 있다. 특히 (Na0 .5K0 .5)NbO3에 5 mol% LiTaO3가 고용되면 상경계를 이루며 높은 압전 특성을 보인다고 알려져 더욱더 각광 받고 있다.Among non-lead piezoelectric ceramic (Na 0 .5 0 .5 K) NbO 3 is representative of the materials that can be substituted for the piezoelectric ceramic of the lead with a basic composition it has the characteristics of high phase transition temperature, a low coercive field, high remnant polarization Is considered one of the In particular (Na 0 .5 0 .5 K) when the NbO 3 5 mol% LiTaO 3 is employed forms a phase boundary known boindago high piezoelectric properties have been more and more popular.

그러나 Na2CO3, K2CO3 등의 원료 물질들의 높은 흡습성과 소결 중의 휘발로 인하여 일반 통상적인 소결 방법으로는 높은 특성을 지닌 알카라인 나이오베이트계 소결체를 제조하기가 어려운 것으로 알려져 있다. 따라서 지금까지는 Hot Press, Spark Plasma Sintering 등과 같은 고가의 제조공정을 이용하여 소결하였다.However, due to the high hygroscopicity of the raw materials such as Na 2 CO 3 , K 2 CO 3 and volatilization during sintering, it is known that it is difficult to produce alkaline niobate-based sintered bodies having high characteristics by general sintering methods. Therefore, until now, sintering was carried out using expensive manufacturing processes such as hot press and spark plasma sintering.

즉, 보다 경제적인 소결법을 강구해야 하는 당위성이 있다. 또한 환경오염, 가격 경쟁력 문제점을 해결하기 위한 방법으로 납산화물 압전 세라믹스를 대처하기 위해서는 이미 알려져 있는 비납계 압전 세라믹스 보다 우수한 유전 및 압전특성이 요구되고 있다.That is, there is a need to seek a more economical sintering method. In addition, in order to solve the environmental pollution and price competitiveness problems, better dielectric and piezoelectric properties are required than the known lead-free piezoelectric ceramics to cope with lead oxide piezoelectric ceramics.

본 발명은 이상과 같은 사항을 감안하여 창출된 것으로서, (NaxK0 .95-xLi0.05)(Nb0.95Ta0.05)O3의 세라믹스 조성물에 1 족 원소 화합물인 Li2CO3와 Na2CO3가 첨가되는 조성으로 우수한 유전 및 압전 특성을 가지는 비납계 압전 세라믹스 조성물 및 그의 제조방법을 제공하는 것을 그 목적으로 한다.The present invention of generating in view of the points as described above, (Na x K 0 .95- x Li 0.05) (Nb 0.95 Ta 0.05) O 3 ceramics, the composition of the first group element compound is Li 2 CO 3 and Na 2 to provide a non-lead piezoelectric ceramic composition and a method for manufacturing with excellent dielectric and piezoelectric properties of a composition that CO 3 is added for that purpose.

이와 같은 목적을 달성하기 위한 본 발명에 따른 비납계 압전 세라믹스 조성물은 (NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3의 세라믹스 조성물에 1족 원소 화합물인 Li2CO3와 Na2CO3가 첨가되는 것을 특징으로 한다.Non-lead piezoelectric ceramic composition according to the present invention for achieving this purpose is (Na x K 0 .95- x Li 0 .05) (Nb 0 .95 Ta 0 .05) 1 -group element to the ceramic composition of the O 3 Li 2 CO 3 and Na 2 CO 3 as a compound is added.

또한, 본 발명에 의한 비납계 압전 세라믹스 조성물은 (NaxK0 .95-xLi0.05)(Nb0.95Ta0.05)O3의 세라믹스 조성물에 1족 원소 화합물인 Li2CO3와 Na2CO3가 첨가되는 것이 바람직하다. In addition, the non-lead piezoelectric ceramic composition according to the invention (Na x K 0 .95-x Li 0.05) (Nb 0.95 Ta 0.05) O 3 in the ceramic composition of 1-group element compound is Li 2 CO 3 and Na 2 CO 3 Is preferably added.

본 발명에 의하면, 비납계 압전 세라믹스 조성물은 (NaxK0 .95-xLi0.05)(Nb0.95Ta0.05)O3이며, 0.46<X<0.52이다. 상기 1족 원소 화합물(Li2CO3, Na2CO3)은 단독 혹은 혼합하여 0.9 ~ 1.1 mol% 첨가되는 것이 바람직하다.According to the present invention, a non-lead piezoelectric ceramic composition (Na x K 0 .95-x Li 0.05) (Nb 0.95 Ta 0.05) O 3 , and, 0.46 <X <0.52. The Group 1 element compound (Li 2 CO 3 , Na 2 CO 3 ) is preferably added alone or mixed 0.9 ~ 1.1 mol%.

또한 본 발명의 다른 양태에 따르면, 비납계 압전 세라믹스 조성물의 제조방법이 제공되는바, 이는 Na2CO3, K2CO3, Li2CO3, Nb2O5, Ta2O5의 시료를 혼합, 분쇄한 후 건조하여 하소하는 단계와, 상기 하소된 시료를 재 하소하는 단계와 상기 하소된 시료를 다시 혼합, 분쇄한 후 건조하는 단계, 상기 건조된 시료를 성형하여 이를 소결하는 단계를 포함하는 것을 특징으로 한다.In addition, according to another aspect of the present invention, there is provided a method for producing a lead-free piezoelectric ceramic composition, which is a sample of Na 2 CO 3 , K 2 CO 3 , Li 2 CO 3 , Nb 2 O 5 , Ta 2 O 5 Mixing, pulverizing, drying and calcining, recalculating the calcined sample, mixing, pulverizing and drying the calcined sample again, and molding the dried sample and sintering it. Characterized in that.

상기의 제조방법에 있어서, 하소 온도는 850℃, 소결 온도는 900 ~ 1100℃가 바람직하다.In the above production method, the calcining temperature is preferably 850 ° C and the sintering temperature is 900 to 1100 ° C.

즉, 본 발명은 (NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3 (0.46<X<0.52)의 세라믹스 조성 물에 1족 원소 화합물인 Li2CO3와 Na2CO3를 첨가하여 우수한 유전 및 압전 특성을 가지는 비납계 압전 세라믹스에 관한 것이며, Na2CO3, K2CO3 등의 원료 물질의 비율을 조절함으로서, 기존의 비납계 압전 세라믹스의 유전 및 압전 특성을 향상시키고, 납 산화물 압전 세라믹스의 경우 납의 휘발성이 문제가 되어 과잉의 납을 첨가하게 되는데, 이와 유사한 접근으로 휘발이 일어나는 A-site 이온들 중 Li, Na 등의 1족 원소를 과잉 첨가하고자 한다.That is, the present invention is (Na x K 0 .95- x Li 0 .05) (Nb 0 .95 Ta 0 .05) O 3 (0.46 <X <0.52) of Li 2 1-group element compound to the ceramic composition of water The present invention relates to a non-lead piezoelectric ceramics having excellent dielectric and piezoelectric properties by adding CO 3 and Na 2 CO 3 , and by controlling the ratio of raw materials such as Na 2 CO 3 and K 2 CO 3 , conventional non-lead piezoelectric ceramics It improves the dielectric and piezoelectric properties of, and in the case of lead oxide piezoelectric ceramics, the volatility of lead becomes a problem, and excess lead is added. Similarly, group 1 elements such as Li and Na among volatilized A-site ions To add an excessive amount.

따라서 본 발명은 NKL-NT 세라믹스에 1족 원소 화합물을 첨가하여 상용 소결 방법으로 제조하여, 납 산화물을 대체할 비납계 압전 세라믹스를 제조방법을 제공하는 것이며, 조성물의 제조방법은 다음 실시예로부터 더욱 명확하게 제안하고자 한다.Accordingly, the present invention is to provide a method for producing a non-lead piezoelectric ceramics to replace lead oxide by adding a Group 1 element compound to NKL-NT ceramics by commercial sintering method, the method of producing the composition is further from the following examples I would like to suggest clearly.

이하, 본 발명의 바람직한 실시예를 첨부한 표와 그림과 사진을 참조하여 상세히 설명한다. 다만, 본 발명이 하술하는 실시예는 본 발명의 전반적인 이해를 돕기 위하여 제공되는 것이며, 본 발명은 기술한 실시예로만 한정되는 것은 아니다.Hereinafter, with reference to the accompanying table, drawings and photos preferred embodiments of the present invention will be described in detail. However, the embodiments described below are provided to help the overall understanding of the present invention, and the present invention is not limited to the described embodiments.

실시예Example

본 발명에 있어서는 (NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3의 세라믹스 조성물에 0.46<X<0.52인 조건으로 산화물 합성 후 첨가제로 1족 원소 화합물인 Li2CO3와 Na2CO3를 과잉 첨가하여 상시 첨가량을 첨가하면서 그에 따른 각각의 시편을 제조하고 그에 따른 구조적 특성과 유전 및 압전 특성을 조사하였다. 이에 따라, 본 실시예에서는 화학식 1의 조성식을 바탕으로 하여 산화물 혼합법에 의해 제조하였으며, 이하 그 제조공정을 설명한다.In the present invention (Na x K x Li 0 .95- 0 .05) (Nb 0 .95 0 .05 Ta) O oxide synthesized in a 0.46 <X <0.52 in terms of the ceramic composition of 3 to 1 element as an additive The specimens were prepared by adding Li 2 CO 3 and Na 2 CO 3 in excess, and the structural and dielectric and piezoelectric properties were investigated. Accordingly, in the present embodiment was prepared by the oxide mixing method on the basis of the formula of the formula (1), the manufacturing process will be described below.

(NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3 + 1 mol% A2CO3 - (화학식 1)(Na x K x Li 0 .95- 0 .05) (Nb 0 .95 0 .05 Ta) O 3 + 1 mol% CO 2 A 3 - (I)

상기 화학식 에서, 0.46<X<0.52이며, 상기 화학식 1에서, A는 1족 원소 Li, Na이다.In the above formula, 0.46 <X <0.52, and in the above formula (1), A is a group 1 element Li or Na.

우선 Na2CO3, K2CO3, Li2CO3, Nb2O5, Ta2O5를 출발물질로 (NaxK0 .95-xLi0.05)(Nb0.95Ta0.05)O3 조성의 세라믹스 분말을 제조하였다. 에탄올과 지르코니아 볼을 이용하여 24시간 분쇄하고 건조한 후, 알루미나 도가니를 이용하여 850℃에서 5시간 동안 하소하였다. 보다 완벽한 상 합성을 위하여 분쇄, 건조, 하소를 두 번 반복하였다. 제조된 (NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3 분말에 첨가제를 넣지 않은 것은 그대로 분쇄, 건조하여 최종분말을 얻었다. 또한 첨가제로 각각, Li2CO3, Na2CO3를 과잉으로 첨가하여 다시 분쇄, 건조하여 최종분말을 얻었다. 최종분말에 PVA를 첨가하여 디스크 형태로 성형한 후, 알루미나 도가니를 이용하여 900~1100℃에서 4시간 동안 열처리하였다. 원료분말의 흡습성이 높기 때문에 모든 공정에서 수분과의 접촉을 최대한 억제하였다. First, Na 2 CO 3, K 2 CO 3, Li 2 CO 3, Nb 2 O 5, Ta 2 O 5 as the starting material (Na x K 0 .95-x Li 0.05) (Nb 0.95 Ta 0.05) O 3 composition Ceramic powder was prepared. It was ground for 24 hours using ethanol and zirconia balls, dried and calcined at 850 ° C. for 5 hours using an alumina crucible. The grinding, drying and calcination were repeated twice for more complete phase synthesis. The prepared (Na x K x Li 0 .95- 0 .05) (Nb 0 .95 0 .05 Ta) O 3 is pulverized not loaded as an additive in a powder, and dried to obtain the final powder. In addition, Li 2 CO 3 and Na 2 CO 3 were added in excess as an additive, and the resultant was pulverized and dried again to obtain a final powder. PVA was added to the final powder to form a disk, and then heat-treated at 900 to 1100 ° C. for 4 hours using an alumina crucible. Due to the high hygroscopicity of the raw material powder, contact with water was suppressed as much as possible in all processes.

최종분말 및 소결된 시편을 XRD 분석을 통하여 상을 확인하였고, SEM을 이용하여 미세조직을 관찰하였다. 전기적 특성을 측정하기 위하여 1 mm 두께로 연마한 시편에 Ag 전극을 도포하여 열처리 한 후, 130℃에서 30분간 2.8 kV/cm 직류 전계로 분극처리하였다. 압전 특성은 Berlincourt type의 d33 측정기로 측정하였으며, 공진 및 반공진 주파수와 공진 저항을 측정하여 전기기계결합계수를 산출하였다.The final powder and the sintered specimens were identified through XRD analysis, and the microstructure was observed using SEM. In order to measure the electrical characteristics, Ag electrode was applied to the specimen polished to a thickness of 1 mm and heat treated, followed by polarization treatment at 130 ° C. for 2.8 kV / cm DC electric field for 30 minutes. Piezoelectric properties were measured by d 33 measuring instrument of Berlincourt type, and electromechanical coupling coefficient was calculated by measuring resonance, anti-resonant frequency and resonance resistance.

각 시편의 XRD 분석결과 모두 페로브스카이트(perovskite) 구조의 피크(peak)가 관찰되었고, 상 분해나 2차상의 형성은 관찰되지 않았다. As a result of the XRD analysis of each specimen, the peak of the perovskite structure was observed, and neither phase decomposition nor secondary phase formation was observed.

도 1은 첨가제를 첨가하지 않은 시편의 소결온도에 따른 미세구조를 나타낸 것이다. 각 열처리 온도에서 4시간 동안 소결하였으며, 1000℃ 이하에서 4시간 동안 소결하였을 때에는 입자들의 크기가 작으며 크기분포는 균일하다. 소결온도가 증가함에 따라 비정상성장입자가 나타났으며, 평균 입자 크기가 증가하였다. 1100℃에서 소결한 시료에서는 1050℃에서 소결한 시료보다 많은 기공이 관찰되었으며, 더 이상의 입자성장은 나타나지 않았고 입자의 크기는 고르게 분포되었다. Na과 K의 비율에 따른 결정들의 성장변화는 크게 나타나지 않았으며, 그 중 Na의 함량이 0.48, 0.5 mol%에서는 입자성장이 활발히 이루어진 것으로 나타났다.Figure 1 shows the microstructure according to the sintering temperature of the specimen without the additive. Sintered at each heat treatment temperature for 4 hours, when sintered at 1000 ℃ or less for 4 hours, the size of the particles are small and the size distribution is uniform. As the sintering temperature increased, abnormal growth particles appeared, and the average particle size increased. More pores were observed in the sample sintered at 1100 ° C than the sample sintered at 1050 ° C. No further grain growth was observed and the particle size was evenly distributed. The growth of the crystals did not show much according to the ratio of Na and K. Among them, the growth of grains was active at 0.48 and 0.5 mol%.

도 2a는 첨가제를 첨가하지 않은 시편의 소결온도에 따른 압전 특성을 나타낸 것이다. 소결온도가 변화함에 따라 압전 상수는 값이 향상되는 것으로 나타났으며, 반면 1050에서 소결한 시료는 현저하게 낮은 값을 나타내었다. Na의 함량이 증가할수록 압전 특성이 향상되었으며, 1000 이상에서 소결한 시료의 특성이 좋은 것 으로 나타났다.Figure 2a shows the piezoelectric properties according to the sintering temperature of the specimen without the additive. As the sintering temperature was changed, the piezoelectric constant was found to be improved, whereas the sample sintered at 1050 showed a significantly lower value. As the Na content increased, the piezoelectric properties were improved, and the samples sintered at 1000 or more were better.

도 2b와 도 2c는 첨가제를 첨가하지 않은 시편의 소결온도에 따른 전기기계결합계수와 유전율을 나타낸 것이다. 소결온도가 증가할수록 전기기계결합계수는 증가하며, 1000℃에서 소결한 시료의 값은 급격히 증가하였다. 1100℃에서 소결한 시료는 Na과 K의 비율에 상관없이 비슷한 값을 나타내었다. 유전율은 1000℃에서 소결한 시료가 가장 높은 값을 나타내었으며, 그 이상의 온도에서는 감소하였다.2b and 2c show the electromechanical coefficient and dielectric constant according to the sintering temperature of the specimen without the additive. As the sintering temperature increased, the electromechanical coefficient increased, and the value of the sample sintered at 1000 ° C increased rapidly. The samples sintered at 1100 ° C showed similar values regardless of the ratio of Na and K. The dielectric constant of the sample sintered at 1000 ° C. was the highest and decreased at higher temperatures.

도 3는 Li2CO3를 1 mol% 첨가한 시편의 소결온도에 따른 미세구조를 나타낸 것이다. Li2CO3를 첨가하지 않았을 때보다 더 뚜렷한 성장을 하였다. 950℃에서 소결한 시료의 입자들은 급격한 성장을 하였고, 그 이상의 온도에서 입자의 성장은 더 이상 이루어지지 않았다. 입자들의 크기는 비교적 균일하며, Na과 K의 비율의 변화에 따른 입자들의 성장은 큰 차이를 보이진 않았으나, Na의 함량이 증가할수록 입자의 크기가 조금씩 커지는 것을 발견할 수 있었다. Figure 3 shows the microstructure according to the sintering temperature of the specimen to which 1 mol% Li 2 CO 3 is added. The growth was more pronounced than when Li 2 CO 3 was not added. The particles of the sample sintered at 950 ° C. showed rapid growth, and growth of the particles at a higher temperature was no longer performed. The size of the particles is relatively uniform, and the growth of the particles by the change of the ratio of Na and K did not show a big difference, but it was found that the size of the particles increases little by little as the Na content increases.

도 4a는 Li2CO3를 1 mol% 첨가한 시편의 소결온도에 따른 압전 특성을 나타낸 것이다. 소결온도가 증가함에 따라 압전 상수의 값도 증가하였으며, 1000℃에서 소결한 시료의 압전 상수 값이 급격히 증가하였다. 미세구조에서도 나타난 것처럼 Na과 K의 비율에 따른 값의 변화는 거의 없었다. Figure 4a shows the piezoelectric properties according to the sintering temperature of the specimen to which 1 mol% Li 2 CO 3 is added. As the sintering temperature increased, the piezoelectric constant value increased, and the piezoelectric constant value of the sample sintered at 1000 ° C. increased rapidly. As shown in the microstructure, there was little change in the value of Na to K ratio.

도 4b와 도 4c는 Li2CO3를 1 mol% 첨가한 시편의 소결온도에 따른 전기기계결합계수와 유전율을 나타낸 것이다. 소결온도가 950℃에서 소결한 시료의 값은 급격히 증가하였으며, 그 이상의 온도에서는 감소하였다. 유전율은 소결온도가 증가 할수록 증가 하였으며, 950℃에서 급격히 증가하였고, 그 이상에서는 천천히 증가하였다. 4b and 4c show the electromechanical coupling coefficient and dielectric constant according to the sintering temperature of the specimen to which 1 mol% Li 2 CO 3 is added. The value of the sample sintered at 950 ° C. increased sharply and decreased at higher temperatures. The dielectric constant increased with increasing sintering temperature, increased rapidly at 950 ℃ and increased slowly above that.

도 5는 Na2CO3를 1 mol% 첨가한 시편의 소결온도에 따른 미세구조를 나타낸 것이다. 첨가제를 첨가하지 않은 시편과 Li2CO3를 1 mol% 첨가한 시편보다 입자의 크기가 크며, 입자의 크기는 균일하며 고른 분포를 보였다. 950℃에서 소결한 시료는 급격한 결정성장을 이루었으며. 온도가 증가할수록 결정들이 입체적으로 성장하였다. 그 중에서 1050℃에서 소결한 Na의 함량이 0.48, 0.5 mol%에서는 입자성장이 활발히 이루어진 것으로 나타났다.5 shows the microstructure according to the sintering temperature of the specimen to which 1 mol% of Na 2 CO 3 is added. The particle size was larger than that of the additive without the additive and 1 mol% of Li 2 CO 3 , and the particle size was uniform and evenly distributed. Samples sintered at 950 ° C experienced rapid crystal growth. As the temperature increased, the crystals grew three-dimensionally. Particularly, it was found that grain growth was actively performed at 0.48 and 0.5 mol% of Na content sintered at 1050 ° C.

도 6a는 Na2CO3를 1 mol% 첨가한 시편의 소결온도에 따른 압전 특성을 나타낸 것이다. 소결온도가 증가할수록 압전 상수의 값이 증가하였으며, 1050℃에서 소결한 시료의 값은 감소하였다.Figure 6a shows the piezoelectric properties according to the sintering temperature of the specimen to which 1 mol% of Na 2 CO 3 is added. As the sintering temperature increased, the piezoelectric constant value increased, and the sample value sintered at 1050 ° C decreased.

도 6b와 도 6c는 Na2CO3를 1 mol% 첨가한 시편의 소결온도에 따른 전기기계결합계수와 유전율을 나타낸 것이다. 소결온도가 증가할수록 전기기계결합계수는 감소하였다. 950℃에서 소결한 시료의 값이 비교적 높았다. 유전율 또한 소결온도가 증가할수록 감소하였으며, 950℃에서 급격히 감소하였고, 그 이상에서는 비교적 일정한 값을 나타내었다.6b and 6c show the electromechanical coupling coefficient and permittivity according to the sintering temperature of the specimen to which 1 mol% of Na 2 CO 3 was added. As the sintering temperature increased, the electromechanical coefficient decreased. The value of the sample sintered at 950 ° C. was relatively high. The dielectric constant also decreased with increasing sintering temperature, and rapidly decreased at 950 ° C.

한 편, 표 1은 압전 자기 조성물 시료 (NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3의 화학조성과 첨가제, 소결온도를 나타낸 표이고, 표 2는 표 1에 나타난 조성을 갖는 압 전 자기 조성물 (NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3의 유전 및 압전 특성을 나타낸 표이다.On the other hand, Table 1 shows the piezoelectric ceramic composition samples (Na x K x Li 0 .95- 0 .05) (Nb 0 .95 0 .05 Ta) O 3, and showing the chemical composition and the additive, the sintering temperature of the table, the table 2 is a table showing the voltage having the composition shown in Table 1, the ceramic composition (Na x K x Li 0 .95- 0 .05) (Nb 0 .95 0 .05 Ta) dielectric and piezoelectric properties of O 3.

시편번호Psalm Number 조성Furtherance 소결온도()Sintering Temperature () xx 첨가제additive 1One 0.4625 0.4625 없음 none 950950 22 10001000 33 10501050 44 11001100 55 0.475 0.475 없음 none 950950 66 10001000 77 10501050 88 11001100 99 0.4875 0.4875 없음 none 950950 1010 10001000 1111 10501050 1212 11001100 1313 0.5 0.5 없음 none 950950 1414 10001000 1515 10501050 1616 11001100 1717 0.5125 0.5125 없음 none 950950 1818 10001000 1919 10501050 2020 11001100 2121 0.4625 0.4625 Li2CO3 1mol%Li 2 CO 3 1mol% 900900 2222 950950 2323 10001000 2424 10501050 2525 0.475 0.475 Li2CO3 1mol%Li 2 CO 3 1mol% 900900 2626 950950 2727 10001000 2828 10501050 2929 0.4875 0.4875 Li2CO3 1mol%Li 2 CO 3 1mol% 900900 3030 950950 3131 10001000 3232 10501050 3333 0.5 0.5 Li2CO3 1mol%Li 2 CO 3 1mol% 900900 3434 950950 3535 10001000 3636 10501050 3737 0.5125 0.5125 Li2CO3 1mol%Li 2 CO 3 1mol% 900900 3838 950950 3939 10001000 4040 10501050 4141 0.4625 0.4625 Na2CO3 1mol%Na 2 CO 3 1mol% 900900 4242 950950 4343 10001000 4444 10501050 4545 0.475 0.475 Na2CO3 1mol%Na 2 CO 3 1mol% 900900 4646 950950 4747 10001000 4848 10501050 4949 0.4875 0.4875 Na2CO3 1mol%Na 2 CO 3 1mol% 900900 5050 950950 5151 10001000 5252 10501050 5353 0.5 0.5 Na2CO3 1mol%Na 2 CO 3 1mol% 900900 5454 950950 5555 10001000 5656 10501050 5757 0.5125 0.5125 Na2CO3 1mol%Na 2 CO 3 1mol% 900900 5858 950950 5959 10001000 6060 10501050

시편번호Psalm Number 소결온도()Sintering Temperature () 유전율(er)Permittivity (e r ) tandtand kp k p d33(pC/N)d 33 (pC / N) 1One 950950 299.49299.49 0.0270.027 0.2830.283 126126 22 10001000 438.97438.97 0.0580.058 0.3060.306 148148 33 10501050 632.09632.09 0.0480.048 0.2750.275 101101 44 11001100 537.45537.45 0.0210.021 0.3540.354 168168 55 950950 255.77255.77 0.0280.028 0.2300.230 113113 66 10001000 354.96354.96 0.0420.042 0.2210.221 140140 77 10501050 628.86628.86 0.0600.060 0.2580.258 127127 88 11001100 554.41554.41 0.0230.023 0.3480.348 172172 99 950950 323.21323.21 0.0280.028 0.2910.291 132132 1010 10001000 459.29459.29 0.0530.053 0.3480.348 147147 1111 10501050 681.64681.64 0.0420.042 0.2750.275 133133 1212 11001100 577.12577.12 0.0210.021 0.3730.373 186186 1313 950950 304.15304.15 0.0230.023 0.1880.188 145145 1414 10001000 470.04470.04 0.0500.050 0.3730.373 162162 1515 10501050 735.13735.13 0.0350.035 0.4030.403 168168 1616 11001100 635.29635.29 0.0200.020 0.3920.392 189189 1717 950950 290.38290.38 0.0220.022 0.2490.249 150150 1818 10001000 415.49415.49 0.0400.040 0.5490.549 168168 1919 10501050 744.12744.12 0.0480.048 0.2750.275 143143 2020 11001100 619.86619.86 0.0200.020 0.4090.409 197197 2121 900900 422.72422.72 0.0730.073 0.3210.321 143143 2222 950950 613.47613.47 0.0240.024 0.5030.503 168168 2323 10001000 621.02621.02 0.0280.028 0.4480.448 236236 2424 10501050 644.71644.71 0.0240.024 0.4310.431 240240 2525 900900 461.73461.73 0.0770.077 0.3730.373 150150 2626 950950 547.26547.26 0.0290.029 0.5490.549 166166 2727 10001000 560.66560.66 0.0280.028 0.4530.453 214214 2828 10501050 623.18623.18 0.0220.022 0.3920.392 242242 2929 900900 388.87388.87 0.0680.068 0.3920.392 152152 3030 950950 623.80623.80 0.0250.025 0.5030.503 164164 3131 10001000 534.90534.90 0.0310.031 0.4420.442 225225 3232 10501050 675.65675.65 0.0240.024 0.4200.420 244244 3333 900900 432.01432.01 0.0560.056 0.4630.463 151151 3434 950950 513.48513.48 0.0310.031 0.5120.512 156156 3535 11001100 503.45503.45 0.0340.034 0.4680.468 222222 3636 10501050 566.67566.67 0.0280.028 0.4150.415 244244 3737 900900 366.95366.95 0.0490.049 0.3860.386 151151 3838 950950 570.57570.57 0.0250.025 0.4480.448 152152 3939 10001000 673.87673.87 0.0230.023 0.4260.426 244244 4040 10501050 635.08635.08 0.0230.023 0.4090.409 247247 4141 900900 326.73326.73 0.0940.094 0.4930.493 128128 4242 950950 339.94339.94 0.0290.029 0.4830.483 128128 4343 10001000 340.34340.34 0.0470.047 0.3920.392 147147 4444 10501050 346.37346.37 0.0440.044 0.3980.398 145145 4545 900900 431.09431.09 0.0980.098 0.3210.321 103103 4646 950950 356.10356.10 0.0290.029 0.4730.473 125125 4747 10001000 348.21348.21 0.0570.057 0.3730.373 139139 4848 10501050 346.94346.94 0.0520.052 0.3800.380 147147 4949 900900 464.66464.66 0.0940.094 0.6330.633 9494 5050 950950 328.28328.28 0.0240.024 0.5080.508 129129 5151 10001000 327.40327.40 0.0610.061 0.3480.348 158158 5252 10501050 359.76359.76 0.0420.042 0.3610.361 143143 5353 900900 447.76447.76 0.0560.056 0.3980.398 125125 5454 950950 331331 0.0240.024 0.5220.522 130130 5555 10001000 344.51344.51 0.0420.042 0.4370.437 145145 5656 10501050 354.93354.93 0.0600.060 0.4090.409 150150 5757 900900 329.42329.42 0.0710.071 0.4260.426 130130 5858 950950 354.60354.60 0.0270.027 0.4480.448 130130 5959 10001000 356.38356.38 0.0410.041 0.4200.420 140140 6060 10501050 356.11356.11 0.0390.039 0.3980.398 147147

(NaxK0 .95- xLi0 .05)(Nb0 .95Ta0 .05)O3 세라믹스에 1족 원소 화합물을 첨가하면 미세조직이 변화하며 소결성이 개선되어 전기적 특성이 향상되었고, 특히, Li2CO3를 첨가할 시에는 압전상수, Na2CO3를 첨가할 시에는 전기기계결합계수가 크게 향상됨을 알 수 있으며, 또한 Na의 함량이 0.5, 0.51 mol%인 시료의 유전 및 압전 특성이 크게 향상됨을 확인할 수 있었다.(Na x K x Li 0 .95- 0 .05) (Nb 0 .95 0 .05 Ta) O 3 ceramics was added when the compound group 1 element and a change in microstructure sinterability is improved to improve the electrical properties, Particularly, when Li 2 CO 3 is added, the piezoelectric constant is increased, and when the Na 2 CO 3 is added, the electromechanical coefficient is greatly improved. It was confirmed that the piezoelectric properties were greatly improved.

이상에서 설명한 바와 같이, 본 발명에 있어서는 (NaxK0 .95-xLi0.05)(Nb0.95Ta0.05)O3 (0.46<X<0.52)의 세라믹스 조성물에 1족 원소 화합물인 Li2CO3와 Na2CO3를 첨가하여 우수한 유전 및 압전 특성을 가지는 비납계 압전 세라믹스 조성물을 개발하였다.As described above, in the present invention (Na x K 0 .95-x Li 0.05) (Nb 0.95 Ta 0.05) O 3 (0.46 <X <0.52) Li 2 in group 1 element compound to the ceramic composition of the CO 3 And Na 2 CO 3 were added to develop a lead-free piezoelectric ceramic composition having excellent dielectric and piezoelectric properties.

또한, 상기의 비납계 압전 세라믹스 조성물은 압전센서와 압전 세라믹 액추에이터로의 적용이 가능하도록 높은 압전상수와 전기기계결합계수를 가지는 효과가 있다.In addition, the non-lead piezoelectric ceramic composition has an effect of having a high piezoelectric constant and an electromechanical coupling coefficient so as to be applicable to the piezoelectric sensor and the piezoelectric ceramic actuator.

Claims (5)

(NaxK0.95-xLi0.05)(Nb0.95Ta0.05)O3의 세라믹스 조성물에 첨가제로 1족 원소 화합물인 Li2CO3 또는 Na2CO3가 첨가되는 것을 특징으로 하는 비납계 압전 세라믹스 조성물.A non-lead piezoelectric ceramic composition characterized in that a Group 1 element compound Li 2 CO 3 or Na 2 CO 3 is added as an additive to the ceramic composition of (Na x K 0.95-x Li 0.05 ) (Nb 0.95 Ta 0.05 ) O 3 . . (NaxK0.95-xLi0.05)(Nb0.95Ta0.05)O3의 세라믹스 조성물에서 0.46<X<0.52인 것에, 첨가제로 1족 원소 화합물인 Li2CO3 또는 Na2CO3가 첨가되는 것을 특징으로 하는 비납계 압전 세라믹스 조성물.0.46 < X < 0.52 in the ceramic composition of (Na x K 0.95-x Li 0.05 ) (Nb 0.95 Ta 0.05 ) O 3 , and the addition of Li 2 CO 3 or Na 2 CO 3, which is a Group 1 element compound, as an additive A lead-free piezoelectric ceramic composition characterized by the above-mentioned. 제 1항 또는 제 2항에 있어서, 상기 1족 원소 화합물은 개별 혹은 혼합되어 첨가되는데, 첨가되는 전체 양이 상기 세라믹스 조성물에 대해 0.9 ~ 1.1 mol% 인 것을 특징으로 하는 비납계 압전 세라믹스 조성물.The non-lead piezoelectric ceramic composition according to claim 1 or 2, wherein the Group 1 element compound is added individually or in mixture, and the total amount added is 0.9 to 1.1 mol% based on the ceramic composition. Na2CO3, K2CO3, Li2CO3, Nb2O5, Ta2O5의 시료를 혼합, 분쇄한 후 건조하여 하소하는 단계와;Mixing, pulverizing and drying the sample of Na 2 CO 3 , K 2 CO 3 , Li 2 CO 3 , Nb 2 O 5 , and Ta 2 O 5 ; 상기 하소 된 시료를 재하소 하는 단계와;Recalculating the calcined sample; 상기 재하소 하는 단계를 거친 세라믹스 조성물에 첨가제로 Li2CO3 또는 Na2CO3 을 혼합하고, 분쇄한 후 건조하는 단계; 및Mixing Li 2 CO 3 or Na 2 CO 3 as an additive to the ceramic composition which has been subjected to the calcination, pulverizing and drying; And 상기 건조된 시료를 성형하여 이를 소결하는 단계;를 포함하는 것을 특징으로 하는 비납계 압전 세라믹스 조성물의 제조방법.Forming the dried sample and sintering it; manufacturing method of a lead-free piezoelectric ceramic composition comprising a. 제 4항에 있어서, 하소 온도는 850℃, 소결 온도는 900 ~ 1100℃로 하는 것을 특징으로 하는 비납계 압전 세라믹스 조성물의 제조방법.The method for producing a lead-free piezoelectric ceramic composition according to claim 4, wherein the calcining temperature is 850 ° C and the sintering temperature is 900 to 1100 ° C.
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