KR100991391B1 - Lead free ceramic composition for ptc thermistor and ptc ceramic thermistor thereby - Google Patents
Lead free ceramic composition for ptc thermistor and ptc ceramic thermistor thereby Download PDFInfo
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Abstract
본 발명은 납성분을 포함하지 않는 PTC 써미스터용 세라믹 조성물 및 이를 이용하여 제조되는 PTC 세라믹 써미스터에 관한 것으로, 납(Pb) 성분을 포함하지 않으며(Lead free) 상온에서 낮은 비저항을 가지고 130℃ 이상의 큐리온도(Tc)를 가지는 PTC 써미스터용 세라믹 조성물을 제공하고, 이를 이용하여 제조되는 PTC 세라믹 써미스터를 제공하는 발명에 관한 것이다.The present invention relates to a ceramic composition for PTC thermistor that does not contain a lead component, and to a PTC ceramic thermistor manufactured using the same, which does not include lead (Pb) and has a low resistivity at room temperature and has a low specific resistance at 130 ° C. or more. It is related with the invention which provides the ceramic composition for PTC thermistors which have temperature Tc, and provides the PTC ceramic thermistor manufactured using the same.
Description
본 발명은 세라믹 조성물에 관한 것으로서, 보다 상세하게는 납성분을 포함하지 않는 PTC 써미스터용 세라믹 조성물에 관한 것이다.The present invention relates to a ceramic composition, and more particularly, to a ceramic composition for PTC thermistor containing no lead component.
PTC(Positive Temperature Coefficient of resistance) 써미스터는 온도가 상승함에 따라 저항이 증가하는 특성을 나타내며, 일반적으로 BaTiO3를 기본조성으로 한다.PTC (Positive Temperature Coefficient of resistance) thermistor shows the characteristic that the resistance increases with increasing temperature, and generally BaTiO 3 is the basic composition.
BaTiO3(BT)계 반도성 세라믹스는 ABO3로 나타내어지는 대표적인 페롭스카이트(perovskite)계 결정구조로된 화합물로서 A-site에 2가의 Ba이온, B-site에 4가의 Ti 이온이 점유하는 형태로 되어 있으며, 온도에 따라 결정구조가 능면체정계(rombohedral), 사면체정계(orthorhombic), 정방정계(tetragonal) 및 입방정 계(cubic)로 전이(transition)되는 다양한(polymorphic) 특성을 나타낸다.BaTiO 3 (BT) -based semiconducting ceramics are compounds of a typical perovskite crystal structure represented by ABO 3 and are occupied by divalent Ba ions at A-site and tetravalent Ti ions at B-site. The crystal structure has various polymorphic properties that transition to a rhombohedral, orthorhombic, tetragonal, and cubic phase depending on temperature.
특히, 1.5VDC 이하에서 PTC 써미스터 주위 온도의 변화에 따른 전기저항을 측정하면 저항-온도 특성이 얻어진다. 이 특성에서 저항값이 급격히 증가하는 온도를 저항급변점 온도(switching 온도) 또는 큐리온도(Curie Temperature)라고 하는데, 일반적으로 최소 저항값 또는 기준 온도(25℃) 저항값의 2배에 대응하는 온도로 정의 되며 재료 특성의 중요한 파라미터(parameter)가 된다.In particular, resistance-temperature characteristics are obtained by measuring the electrical resistance of the PTC thermistor at ambient temperatures below 1.5V DC . In this characteristic, the temperature at which the resistance value increases sharply is called resistance temperature (switching temperature) or Curie temperature, which is generally the temperature corresponding to twice the minimum resistance value or the reference temperature (25 ° C) resistance value. It is defined as, and is an important parameter of material properties.
BaTiO3 세라믹스에서 큐리온도(Tc)는 강유전상의 정방정계에서 상유전상의 입방정계로 전이되는 130℃의 온도를 의미하는데, PTC 써미스터의 작동온도를 130℃이상으로 상승시키기 위해서는 A-site에 납(Pb)을 치환한 PbTiO3가 사용되고 있다.In BaTiO 3 ceramics, the Curie temperature (Tc) is a temperature of 130 ° C that transitions from the tetragonal phase of ferroelectric phase to the cubic phase of phase dielectric. To increase the operating temperature of PTC thermistor above 130 ° C, lead (Pb) ) Substituted PbTiO 3 is used.
PbTiO3는 490℃의 큐리온도(Tc)를 가지므로 충분히 작동 온도를 상승시킬 수 있다. 그러나, 납(Pb) 성분은 인체에 유해하고 환경오염을 유발할 수도 있으며, 또한 소자내에서 증발된 납성분은 소자들의 균일성을 악화시키는 요인이 될 수도 있다.Since PbTiO 3 has a Curie temperature (Tc) of 490 ° C., it is possible to sufficiently raise the operating temperature. However, the lead (Pb) component is harmful to the human body and may cause environmental pollution, and the lead component evaporated in the device may also deteriorate the uniformity of the device.
최근 인간과 환경에 대한 친화 소재에 대한 관심이 증대되면서 납(Pb) 성분을 함유한 PTC 써미스터 소재를 대신하여 BaTiO3 보다 높은 큐리온도(Tc)를 가지는 무연계 PTC 써미스터 조성물을 개발하기 위한 연구가 최근 활발히 진행되고 있다.Recently, as interest in environmentally friendly materials for humans and the environment has increased, researchers have developed a lead-free PTC thermistor composition having a higher Curie temperature (Tc) than BaTiO 3 in place of a PTC thermistor material containing lead (Pb). It is actively progressed recently.
이러한 120℃이상의 큐리온도(Tc)를 가지는 무연계 PTC 써미스터 중 대표적 인 후보 물질들로 페롭스카이트(perovskite)구조를 가지는 Bi1/2Na1/2TiO3(BiNT), Bi1/2K1/2TiO3(BiKT), NaNbO3, BiFeO3 등이 소개되었다. Bi 1/2 Na 1/2 TiO 3 (BiNT), Bi 1/2 K having a perovskite structure as representative candidate materials among the lead-free PTC thermistors having a Curie temperature (Tc) of 120 ° C. or higher. 1/2 TiO 3 (BiKT), NaNbO 3 , BiFeO 3, and the like have been introduced.
그러나, 상기 소재들에 대한 PTC 특성은 아직 충분히 검증되지 못하였으며, 특히 자동차용 히터에 사용되는 고 큐리온도(High Tc > 130℃)를 갖는 세라믹 조성물 개발은 아직 미미한 실정이다.However, the PTC properties of the materials have not been fully verified, and in particular, the development of ceramic compositions having high Curie temperatures (High Tc> 130 ° C.) used in automotive heaters is still insignificant.
본 발명은 납(Pb) 성분을 포함하지 않으며(Lead free) 상온에서 낮은 비저항을 가지고 130℃ 이상의 큐리온도(Tc)를 가지는 PTC 써미스터용 세라믹 조성물을 제공하는 것을 그 목적으로 하고 있다.An object of the present invention is to provide a ceramic composition for PTC thermistor which does not contain lead (Pb) component and has a low specific resistance at room temperature and has a Curie temperature (Tc) of 130 ° C. or higher.
아울러, 본 발명은 상기 세라믹 조성물을 이용하여 제조되는 PTC 세라믹 써미스터를 제공하는 것을 그 목적으로 하고 있다.Moreover, an object of this invention is to provide the PTC ceramic thermistor manufactured using the said ceramic composition.
본 발명이 이루고자 하는 과제들은 이상에서 언급한 기술적 과제들로 제한되지 않으며, 언급되지 않은 또 다른 기술적 과제들은 아래의 기재로부터 당업자에게 명확하게 이해될 수 있을 것이다.The objects to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.
본 발명에 따른 PTC 써미스터용 세라믹 조성물은 Na0.5K0.5NbO3(NKN)가 BaTiO3(BT)의 고용체로 형성되는 하기 [화학식 1]의 세라믹 물질을 포함하는 것을 특징으로 한다.The ceramic composition for PTC thermistor according to the present invention is characterized in that Na 0.5 K 0.5 NbO 3 (NKN) comprises a ceramic material of the following [Formula 1] is formed of a solid solution of BaTiO 3 (BT).
[화학식 1][Formula 1]
(1-x)BT-xNKN (0<x≤0.05)(1-x) BT-xNKN (0 <x≤0.05)
여기서, 상기 세라믹 조성물은 Nb2O5 분말로 구비되는 도판트 물질을 더 포함하는 것을 특징으로 하고, 상기 Nb2O5는 0 내지 0.2 mol%의 범위 내에서 첨가되는 것을 특징으로 한다.Here, the ceramic composition is characterized in that it further comprises a dopant material is provided with Nb 2 O 5 powder, the Nb 2 O 5 is characterized in that it is added within the range of 0 to 0.2 mol%.
아울러, 본 발명에 따른 PTC 세라믹 써미스터는 상술한 세라믹 조성물로 제조되는 것을 특징으로 한다.In addition, the PTC ceramic thermistor according to the present invention is characterized by being manufactured from the ceramic composition described above.
아울러, 본 발명에 따른 PTC 세라믹 써미스터 제조 방법은 99.9%의 고순도 BaTiO3(BT)를 마련하는 단계와, 상기 BaTiO3(BT)에 Na0.5K0.5NbO3(NKN)을 고용체로 형성하여 (1-x)BT-xNKN(0<x≤0.05) 세라믹 원료분말을 제조하는 단계와, 상기 세라믹 원료분말을 HDPE (High Density Polyethylene) jar에 넣어 증류수를 분산매로 하여 24시간 동안 제 1 볼밀링시키는 단계와, 상기 제 1 볼밀링 처리된 상기 세라믹 원료분말을 120℃에서 건조시킨 후, 유발에 넣고 분쇄하는 단계와, 분쇄된 상기 세라믹 원료분말을 알루미나 도가니에 넣고 1000℃에서 2시간 동안 하소하는 단계와, 하소된 상기 세라믹 원료분말을 HDPE (High Density Polyethylene) jar에 넣어 증류수를 분산매로 하여 24시간 동안 제 2 볼밀링시키는 단계 및 상기 제 2 볼밀링 처리된 상기 세라믹 원료분말을 금형에 넣고 1 ton/cm2의 압력을 가하여 센서 형태로 제조하는 단계를 포함하는 것을 특징으로 한다.In addition, the PTC ceramic thermistor manufacturing method according to the present invention comprises the steps of preparing a high purity BaTiO 3 (BT) of 99.9%, and by forming a solid solution of Na 0.5 K 0.5 NbO 3 (NKN) in the BaTiO 3 (BT) (1 (x) preparing a BT-xNKN (0 <x≤0.05) ceramic raw powder, and putting the ceramic raw powder in a high density polyethylene (HDPE) jar to first ball milling for 24 hours using distilled water as a dispersion medium. And drying the first ball milling ceramic raw powder at 120 ° C., and then pulverizing the ceramic raw material powder in a mortar, and calcining the ground ceramic raw powder in an alumina crucible at 1000 ° C. for 2 hours. , Putting the calcined ceramic raw powder in a HDPE (High Density Polyethylene) jar to a second ball milling for 24 hours with distilled water as a dispersion medium and the second ball milled ceramic raw powder into a
본 발명에 따른 (1-x)BT-xNKN(0<x≤0.05) 세라믹 물질을 포함하는 PTC 써미스터용 조성물에 의하면 납(Pb) 성분을 함유하지 않으면서도 상온에서 낮은 비저항값과 130℃ 이상의 큐리온도(Tc)를 갖는 PTC 세라믹 써미스터의 제조가 가능해 지 게 된다. 따라서, 본 발명은 자동차용 히터 뿐만아니라 고성능을 요구하는 PTC 히터, PCT 한류기, PTC 레지스터 등에의 다양하게 응용할 수 있도록 하는 효과를 제공한다.According to the composition for PTC thermistor containing (1-x) BT-xNKN (0 <x≤0.05) ceramic material according to the present invention, it does not contain lead (Pb) component and has low resistivity at room temperature and curie of 130 ° C or higher. It becomes possible to manufacture a PTC ceramic thermistor having a temperature Tc. Accordingly, the present invention provides an effect that can be applied not only to automobile heaters but also to PTC heaters, PCT current limiters, PTC resistors, and the like which require high performance.
본 발명에서는 PTC 써미스터용 세라믹 조성물의 주성분으로서 고순도의 BaTiO3(BT)를 사용하되, 비납계 압전체 재료로서 사용되어 오던 Na0.5K0.5NbO3(NKN)가 고용된 형태로 사용함으로써 고 큐리온도(High Tc > 130℃)를 확보하도록 한다. In the present invention, high purity BaTiO 3 (BT) is used as a main component of the ceramic composition for PTC thermistor, and Na 0.5 K 0.5 NbO 3 (NKN), which has been used as a lead-free piezoelectric material, is used in a solid solution. High Tc> 130 ℃).
아울러, 본 발명은 첨가제로 Nb2O5를 사용하여 유효한 PTC 특성을 확보할 수 있도록 한다.In addition, the present invention allows the use of Nb 2 O 5 as an additive to ensure effective PTC properties.
이하에서는 본 발명에 따른 PTC 써미스터용 세라믹 조성물에 대하여 구체적인 실시예들 및 비교예들을 들어 설명한다. 여기에 기재되지 않은 내용은 이 기술 분야에서 숙련된 자이면 충분히 기술적으로 유추할 수 있는 것이므로 그 설명을 생략한다.Hereinafter, specific examples and comparative examples will be described with respect to the ceramic composition for PTC thermistors according to the present invention. Details not described herein are omitted because they can be sufficiently inferred by those skilled in the art.
먼저, 본 발명에 따른 PTC 써미스터용 세라믹 조성물의 주요 성분은 하기 [화학식 1]을 따른다.First, the main component of the ceramic composition for PTC thermistor according to the present invention follows the following [Formula 1].
[화학식 1][Formula 1]
(1-x)BT-xNKN (0<x≤0.03)(1-x) BT-xNKN (0 <x≤0.03)
상기 [화학식 1]에서 0<x≤0.03로 정의되는데, 그 이유는 x가 0이하 이거나 0.03를 초과하게 되면 양호한 소결체를 얻을 수 없게 되어, 세라믹 조성물을 PTC 히터, PCT 한류기, PTC 레지스터 등에의 응용하기 어려워지는 문제가 있기 때문이다.In Formula 1, 0 <x ≦ 0.03, which is defined as the reason why when x is less than 0 or more than 0.03, a good sintered body cannot be obtained. This is because there is a problem that is difficult to apply.
즉, BaTiO3(BT)는 절연체로서 상온에서 부도체 특성을 나타내는데, Na0.5K0.5NbO3(NKN)을 적정량 고용하게 되면 상온에서의 저항이 급격하게 낮아져 전도성을 가지게 된다. 뿐만 아니라 Na0.5K0.5NbO3(NKN)이 가지는 큐리온도가 420℃ 정도로 높아서 순수 BaTiO3(BT)가 가지는 120℃ 정도의 큐리온도가 Na0.5K0.5NbO3(NKN)을 고용함으로써 향상되는 것이다. 그러나 과량의 Na0.5K0.5NbO3(NKN)(0.03mol% 초과)을 고용하게 되면 고용되지 못한 Na0.5K0.5NbO3(NKN) 입자의 일부가 입계(grain boundary)에 존재하면서 입계 저항을 증가시켜 전도성을 감소시키며, 이로 인하여 상온에서의 비저항이 급격하게 증가하게 된다. 따라서, 본 발명에 따른 고용 범위를 준수하는 것이 바람직하다.That is, BaTiO 3 (BT) exhibits insulator characteristics at room temperature as an insulator, and if Na 0.5 K 0.5 NbO 3 (NKN) is dissolved in an appropriate amount, the resistance at room temperature is rapidly lowered to have conductivity. In addition, the Curie temperature of Na 0.5 K 0.5 NbO 3 (NKN) is about 420 ° C, and the Curie temperature of about 120 ° C of pure BaTiO 3 (BT) is improved by employing Na 0.5 K 0.5 NbO 3 (NKN). . However, employing an excess of Na 0.5 K 0.5 NbO 3 (NKN) (greater than 0.03 mol%) increases the grain boundary resistance due to the presence of some of the unsustained Na 0.5 K 0.5 NbO 3 (NKN) particles at the grain boundary. This decreases the conductivity, which leads to a sharp increase in specific resistance at room temperature. Therefore, it is desirable to comply with the employment range according to the invention.
다음으로, 본 발명에 따른 PTC 써미스터용 세라믹 조성물에는 0초과 0.05이하mol%의 범위 내에서 Nb2O5 도판트 물질을 첨가 할 수 있다. Nb2O5 도판트 물질은 PTC 점프 특성을 약간 감소시켰으나, 여전히 유효한 PTC 특성을 유지할 수 있다. Next, an Nb 2 O 5 dopant material may be added to the ceramic composition for PTC thermistors according to the present invention within a range of 0 to 0.05 mol%. The Nb 2 O 5 dopant material slightly reduced the PTC jump properties, but can still maintain effective PTC properties.
그러나, 0.05mol%를 초과하게 첨가되는 경우 상온비저항이 급격히 증가하여 절연체로 변화되기 때문에 PTC 특성이 사라져 버리는 문제가 발생할 수 있으므로 본 발명에 따른 첨가 범위를 준수하는 것이 바람직하다.However, when added in excess of 0.05 mol%, since the room temperature specific resistance increases rapidly and changes into an insulator, a problem may occur that the PTC characteristic disappears. Therefore, it is preferable to observe the addition range according to the present invention.
본 발명은 상술한 PTC 써미스터용 세라믹 조성물을 이용하여, 고상합성법으로 PTC 세라믹 써미스터를 제작하는 방법을 제공한다.The present invention provides a method for producing a PTC ceramic thermistor by the solid phase synthesis method using the above-described ceramic composition for PTC thermistor.
먼저 99.9%의 고순도 BaTiO3, Nb2O5, 분말을 사용하여 불순물의 영향이 최소화될 수 있도록 한다. First, high purity BaTiO 3 , Nb 2 O 5 , Powders can be used to minimize the effects of impurities.
(1-x)BT-xNKN (0<x≤0.03) 세라믹에 도판트 물질로 Nb2O5(99.9%)를 첨가하되, Nb2O5는 0초과 0.05이하mol%까지 첨가할 수 있다. 이때, 원료분말은 전자저울을 사용하여 10-4g까지 정밀하게 평량하는 것이 바람직하다.Nb 2 O 5 (99.9%) may be added to the (1-x) BT-xNKN (0 <x ≦ 0.03) ceramic as a dopant material, but Nb 2 O 5 may be added to 0 mol and up to 0.05 mol%. At this time, the raw material powder is preferably weighed precisely to 10 -4 g using an electronic balance.
다음에는, 상기 원료분말을 HDPE(High Density Polyethylene) jar에 넣고 증류수를 분산매로 하여 24시간 동안 지르코니아 볼을 이용하여 제 1 볼밀링 공정을 수행한다.Next, the raw powder is placed in a high density polyethylene (HDPE) jar and a first ball milling process is performed using zirconia balls for 24 hours using distilled water as a dispersion medium.
그 다음에는, 제 1 볼밀링 공정으로 혼합된 시료를 120℃에서 건조시킨 후, 유발에 넣고 분쇄한다.Then, the sample mixed in the first ball milling process is dried at 120 ° C., and then placed in a mortar and ground.
그 다음에는, 분쇄된 원료 분말을 알루미나 도가니에 넣어 1000℃에서 2시간 동안 하소한다. Then, the ground raw powder is placed in an alumina crucible and calcined at 1000 ° C. for 2 hours.
그 다음에는, 하소한 분말을 다시 HDPE(High Density Polyethylene) jar에 넣고 증류수를 분산매로 하여 24시간 동안 동일한 방법으로 제 2 볼밀링 공정을 수행한다.Then, the calcined powder is put back into a high density polyethylene (HDPE) jar, and a second ball milling process is performed for 24 hours using distilled water as a dispersion medium.
그 다음에는, 다시 건조 후 분쇄된 시료를 원통형 금형 (Φ: 10 mm)에 넣고, 1 ton/cm2의 압력을 가하여 디스크 형태의 PTC 세라믹 써미스터로 성형한다. Then, the dried and pulverized sample is placed in a cylindrical mold (Φ: 10 mm) and molded into a disc-shaped PTC ceramic thermistor by applying a pressure of 1 ton / cm 2 .
그 다음에는, 성형된 PTC 세라믹 써미스터를 1300℃에서 4시간 동안 소결하여 사용한다. Next, the molded PTC ceramic thermistor is used by sintering at 1300 ° C. for 4 hours.
상술한 바와 같이 제작된 PTC 세라믹 써미스터들의 특성에 대해 설명하면 다음과 같다. The characteristics of the PTC ceramic thermistors manufactured as described above are as follows.
먼저, PTC 특성을 분석하기 위해서는 상기 제작한 디스크 형태의 PTC 세라믹 써미스터를 시편으로 사용한다. First, in order to analyze PTC characteristics, the prepared disk-type PTC ceramic thermistor is used as a specimen.
다음에는, Ag-Zn 전극을 디스크의 상부와 하부면에 각각 형성시킨 후, 상온에서부터 320℃까지 온도를 증가시키면서 시편의 저항을 측정한다. 저항을 측정하기 위하여 Digital Multimeter(Agilent, 34410A)를 이용하며, 하기 [방정식 1]을 이용하여 비저항 ρ를 계산한다.Next, Ag-Zn electrodes are formed on the upper and lower surfaces of the disk, respectively, and then the resistance of the specimen is measured while increasing the temperature from room temperature to 320 ° C. A digital multimeter (Agilent, 34410A) is used to measure the resistance, and the specific resistance ρ is calculated using
[방정식 1]
여기서 R은 저항, d는 시편의 두께, A는 시편의 면적이다. Where R is the resistance, d is the thickness of the specimen, and A is the area of the specimen.
그 다음으로, 온도 변화에 따른 저항의 기울기를 나타내는 저항 온도 계수 α는 하기 [방정식 2]로부터 계산한다.Next, the resistance temperature coefficient α representing the slope of the resistance according to the temperature change is calculated from the following [Equation 2].
[방정식 2][Equation 2]
여기서, T1= Tc, T2= T1+80℃, R1은 T1에서의 저항, R2는 T2에서의 저항이다.Here, T 1 = Tc, T 2 = T 1 + 80 ° C., R 1 is the resistance at T 1 , and R 2 is the resistance at T 2 .
도 1은 본 발명에 따른 PTC 써미스터용 세라믹의 온도별 비저항을 측정한 그래프이다.1 is a graph measuring the specific resistance of each temperature of the ceramic for PTC thermistor according to the present invention.
도 1을 참조하면, PTC 써미스터용 세라믹 제조를 위하여 0.99BaTiO3-0.01(Na0.5K0.5)NbO3- x mol%Nb2O5 조성물을 사용하였다. 이들은 모두 균일한 미세구조를 나타내고 있으므로 양호한 소결체를 얻을 수 있었다.Referring to Figure 1, 0.99 BaTiO 3 -0.01 (Na 0.5 K 0.5 ) NbO 3 -x mol% Nb 2 O 5 composition was used to prepare a ceramic for PTC thermistor. Since these all showed uniform microstructure, favorable sintered compact was obtained.
시편은 1300℃에서 4시간 동안 소결(Sintering temp.: 130℃, Sintering time : 4h)하고 시간당 600℃로 냉각(Cooling rate: 600℃/hr)하여 제조하였으며, Nb2O5 의 첨가량이 없는 경우(x=0)를 실시예1로 나타내고, 0.025mol% 첨가한 경우(x=0.025)를 실시예2로 나타내고, 0.05mol% 첨가한 경우(x=0.05)를 실시예3으로 나타내었다. 이때, 설명되는 x는 상술한 [화학식 1]에서의 x와 다른 계수이며, 실험 데이터 분석 상 x축에 설명되는 상수값을 용이하게 표현하기 위하여 사용한 것이다.Specimens were prepared by sintering at 1300 ° C. for 4 hours (Sintering temp .: 130 ° C., Sintering time: 4 h) and cooling to 600 ° C. per hour (Cooling rate: 600 ° C./hr), where Nb 2 O 5 was not added. (x = 0) is shown as Example 1, the case where 0.025 mol% is added (x = 0.025) is shown as Example 2, and the case where 0.05 mol% is added (x = 0.05) is shown as Example 3. In this case, x described is a coefficient different from x in the above [Formula 1], and is used to easily express a constant value described on the x-axis in analyzing the experimental data.
여기서, 실시예1의 경우 큐리온도(Tc)는 138℃를 나타내었으며, 비저항 ρ1은 19Ω·㎝로 낮은 비저항 특성을 나타내었다.Here, in Example 1, the Curie temperature (Tc) was 138 ° C., and the specific resistance ρ 1 was 19 kΩ · cm, which showed low specific resistance.
실시예2의 경우 큐리온도(Tc)는 137℃를 나타내었으며, 비저항 ρ2은 49Ω·㎝로 낮은 비저항 특성을 나타내었다.In Example 2, the Curie temperature (Tc) was 137 ° C., and the specific resistance ρ 2 was 49 kΩ · cm, which showed low specific resistance.
실시예3의 경우 큐리온도(Tc)는 138℃를 나타내었으며, 비저항 ρ3은 136Ω·㎝로 낮은 비저항 특성을 나타내었다.In Example 3, the Curie temperature (Tc) was 138 ° C. and the specific resistance ρ 3 was 136 Ω · cm, which showed low specific resistance.
도 2는 본 발명에 따른 PTC 써미스터용 세라믹에 첨가되는 Nb2O5의 농도별 비저항을 측정한 그래프이다.Figure 2 is a graph measuring the specific resistance of each concentration of Nb 2 O 5 added to the PTC thermistor ceramic according to the present invention.
도 2를 참조하면, 0.99BT-0.01NKN 세라믹에 Nb2O5를 첨가함에 따라 상온비저항은 점차로 증가하는 것을 알 수 있다. 반면에 하기 도 3 및 도 4를 참조하면, 큐리온도(Tc) 및 PTC 점프(Jump) 특성은 오히려 감소되고 있음을 알 수 있다.2, it can be seen that the room temperature specific resistance gradually increases as Nb 2 O 5 is added to the 0.99BT-0.01NKN ceramic. On the other hand, referring to Figures 3 and 4, it can be seen that the Curie temperature (Tc) and PTC jump (Jump) characteristics are rather reduced.
도 3은 본 발명에 따른 PTC 써미스터용 세라믹에 첨가되는 Nb2O5의 농도별 큐리온도를 측정한 그래프이고, 도 4는 본 발명에 따른 PTC 써미스터용 세라믹에 첨가되는 Nb2O5의 농도별 PTC 점프 특성을 측정한 그래프이다.3 is a graph measuring the Curie temperature for each concentration of Nb 2 O 5 added to the PTC thermistor ceramic according to the present invention, and FIG. 4 for each concentration of Nb 2 O 5 added to the PTC thermistor ceramic according to the present invention. It is a graph which measured PTC jump characteristic.
도 3 및 도 4를 참조하면, 0.05 mol%까지 Nb2O5가 도핑되었을 때는 PTC 특성이 나타났으나 0.1 mol% 이상의 Nb2O5가 첨가되면 상온비저항이 급격히 증가하며 절연체로 변하여 PTC 특성은 구현되지 않았다. 0.05 mol%의 Nb2O5가 도핑된 0.99BT-0.01NKN 세라믹스의 큐리온도 (Tc)는 약 136℃ 정도를 나타내었으며, 136 Ω·㎝의 여전히 낮은 상온비저항과 최대비저항과 최소비저항의 비(ρmax/ρmin)를 나타내는 PTC 점프 특성은 3.2×103을 나타내었다.3 and 4, when Nb 2 O 5 was doped to 0.05 mol%, PTC characteristics appeared, but when Nb 2 O 5 or more added at 0.1 mol%, the room temperature resistivity increased rapidly and turned into an insulator. Not implemented Curie temperature (T c ) of 0.99BT-0.01NKN ceramics doped with 0.05 mol% of Nb 2 O 5 was about 136 ° C, and the low specific temperature resistance of 136 Ω · ㎝ and the ratio of maximum specific resistance and minimum specific resistance The PTC jump characteristic (ρ max / ρ min ) was 3.2 × 10 3 .
도 5는 본 발명에 따른 PTC 써미스터용 세라믹에 첨가되는 Nb2O5의 농도별 저항온도계수 특성을 측정한 그래프이다.5 is a graph measuring the resistance temperature coefficient characteristics of the concentration of Nb 2 O 5 added to the PTC thermistor ceramic according to the present invention.
도 5를 참조하면, 본 발명의 실시예1 내지 실시예3에 따른 PTC 세라믹 써미스터는 각각 7.9, 7.0, 5.3 %/℃의 저항온도계수(Temperature Coefficient of Resistivity)를 갖는 우수한 PTCR 특성을 나타내고 있음을 알 수 있다.Referring to FIG. 5, PTC ceramic thermistors according to Examples 1 to 3 of the present invention exhibit excellent PTCR characteristics having a resistance coefficient of temperature of 7.9, 7.0, and 5.3% / ° C., respectively. Able to know.
이상 첨부된 도면 및 표를 참조하여 본 발명의 실시예들을 설명하였으나, 본 발명은 상기 실시예들에 한정되는 것이 아니라 서로 다른 다양한 형태로 제조될 수 있으며, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자는 본 발명의 기술 적 사상이나 필수적인 특징을 변경하지 않고서 다른 구체적인 형태로 실시될 수 있다는 것을 이해할 수 있을 것이다. 그러므로 이상에서 기술한 실시예들은 모든 면에서 예시적인 것이며 한정적이 아닌 것으로 이해해야만 한다.Although the embodiments of the present invention have been described above with reference to the accompanying drawings and tables, the present invention is not limited to the above embodiments, but may be manufactured in various forms, and common knowledge in the art to which the present invention pertains. Those skilled in the art can understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.
도 1은 본 발명에 따른 PTC 써미스터용 세라믹의 온도별 비저항을 측정한 그래프.1 is a graph measuring the specific resistance of each temperature of the ceramic for PTC thermistor according to the present invention.
도 2는 본 발명에 따른 PTC 써미스터용 세라믹에 첨가되는 Nb2O5의 농도별 상온비저항을 측정한 그래프.Figure 2 is a graph measuring the room temperature specific resistance of the concentration of Nb 2 O 5 added to the ceramic for PTC thermistor according to the present invention.
도 3은 본 발명에 따른 PTC 써미스터용 세라믹에 첨가되는 Nb2O5의 농도별 큐리온도를 측정한 그래프.Figure 3 is a graph measuring the Curie temperature for each concentration of Nb 2 O 5 added to the ceramic for PTC thermistor according to the present invention.
도 4는 본 발명에 따른 PTC 써미스터용 세라믹에 첨가되는 Nb2O5의 농도별 PTC 점프 특성을 측정한 그래프.Figure 4 is a graph measuring the PTC jump characteristics for each concentration of Nb 2 O 5 added to the ceramic for PTC thermistor according to the present invention.
도 5는 본 발명에 따른 PTC 써미스터용 세라믹에 첨가되는 Nb2O5의 농도별 저항온도계수 특성을 측정한 그래프.5 is a graph measuring the resistance temperature coefficient characteristics of the concentration of Nb 2 O 5 added to the ceramic for PTC thermistor according to the present invention.
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