• 제목/요약/키워드: Positive temperature coefficient of resistance (PTCR)

검색결과 46건 처리시간 0.022초

PTCR 나노 복합기능 소재의 전류 차단 특성 연구 (PTCR Characteristics of Multifunctional Polymeric Nano Composites)

  • 김재철;박기헌;서수정;이영관;이성재
    • 폴리머
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    • 제26권3호
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    • pp.367-374
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    • 2002
  • 본 연구에서는 나노 입자의 카본블랙을 결정성 고분자에 분산시켜 특정한 온도에서 저항이 급격하게 증가하는 positive temperature coefficient resistance (PTCR) 특성을 연구하였다. 열가소성 수지를 이용한 PTCR 소재를 열처리에 의하여 고분자의 큐리온도를 조절할 수 있었다. 나노입자 카본블랙이 고분자 구조내에 고르게 분산이 되지 않고, 카본블랙의 함량이 과다하면 negative temperature coefficient resistance (NTCR) 현상이 발생하였다. 카본블랙의 함량과 내부전압을 조절함에 따라 발열 온도를 선정할 수 있었다. 카본블랙의 함량에 따라 전기 전도성이 다르게 나타났으며, 20 wt% 이상에서는 저항이 거의 일정하게 나타난다는 것을 확인하였다. 본 연구에서 제조된 PTCR 소재는 반복적인 가열 냉각에 따른 상온에서의 초기 저항의 변화가 거의 없어 재현성을 확인하였으며, 초기의 낮은 저항에 의한 순간적인 발열에 의하여 저온에서의 PTCR 성능이 향상되었다.

Current-voltage Characteristics of Ceramics with Positive Temperature Coefficient of Resistance

  • Li, Yong-Gen;Cho, Sung-Gurl
    • 한국세라믹학회지
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    • 제40권10호
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    • pp.921-924
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    • 2003
  • A current-voltage relation for Positive Temperature Coefficient of Resistance (PTCR) ceramic was derived and compared with the experimental data. The new current-voltage relation was developed based on Heywangs double Schottky barrier model and a bias distribution across the grain boundary. The voltage limitation V < 4${\Phi}$$\sub$b/ suggested by Heywang is no longer necessary in the new expression for the voltage dependence of the resistance. The pulsed voltages were applied to the PTCR ceramic specimen in order to avoid possible temperature variation during the measurement.

분쇄 방법 및 하소온도에 따른 Doner-doped BaTiO3의 전기적 특성 (Electrical Properties of Donor-doped BaTiO3 Ceramics by Attrition Milling and Calcination Temperature)

  • 이정철;명성재;전명표;조정호;김병익;신동욱
    • 한국전기전자재료학회논문지
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    • 제21권3호
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    • pp.217-221
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    • 2008
  • In this study, We have been investigated the effect of calcination temperature and high-energy ball-milling of powder influences the $BaTiO_3$-based PTCR(Positive Temperature coefficient Resistance) characteristics and microstructure. The mixed powder was obtained from $BaCO_3$, $TiO_2$, $CeO_2$ ball-milled in attrition mill. The mixed powder was calcine from 1000 $^{\circ}C$ to 1200 $^{\circ}C$ in air and then it was sintered in reduction- re-oxidation atmosphere. As a result, The room-temperature electrical resistivity decreased and increased with increasing calcination temperature. specially, Attrition milled powder could have low room-temperature resistivity and high PTC jump order at 1100 $^{\circ}C$. attrition milling had lower room-temperature resistivity than ball milling. Particle size decreased by Attrition milling of powder influences in calcination temperature and room-temperature resistivity.

$BaTiO_3$계 박막형 열전센서소자 개발 (Development of Thermal Sensor Devices in the $BaTiO_3$ Systems)

  • 송민종
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 제5회 학술대회 논문집 일렉트렛트 및 응용기술연구회
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    • pp.100-104
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    • 2003
  • $BaTiO_3$ ceramic thin films were manufactured by rf/dc magnetron sputter technique. We have investigated crystal structure, surface morphology and PTCR(positive-temperature coefficient of resistance) characteristics of the specimen depending on second heat-treatment temperatures. Second heat treatments of the specimen were performed in the temperature range of 400 to $1350^{\circ}C$. X-ray diffraction patterns of $BaTiO_3$ thin films show that the specimen heat treated below $600^{\circ}C$ is an amorphous phase and the one heat treated above $1100^{\circ}C$ forms a poly-crystallization. In the specimen heat-treated at $1300^{\circ}C$, a lattice constant ratio (c/a) was 1.188. Scanning electron microscope(SEM) image of $BaTiO_3$ thin films of the specimen heat treated in between 900 and $1100^{\circ}C$ shows a grain growth. At $1100^{\circ}C$, the specimen stops grain-growing and becomes a poly-crystallization.

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고온가압소결한 $\alpha-SiC-ZrB_2$ 복합체의 전기전도기구 (Electrical Conductive Mechanism of Hot-pressed $\alpha-SiC-ZrB_2$ Composites)

  • 신용덕;주진영;권주성
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제48권2호
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    • pp.104-108
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    • 1999
  • The electrical conductive mechanism and temperature dependence of electrical resistivity of $\alpha-SiC-ZrB_2$ composites with $ZrB_2$ contents were investigated. The electrical resistivity of hot-pressed composites was measured by the Pauw method form $25^{\circ} to 700^{\circ}C$. The electrical resistivity of the composites follow the electrical conduction model for a homogeneous mixture of two kind of particles with different conductivity. Also, the electrical resistivity versus temperature curves indicate the formation of local chains of $ZrB_2$ particles. In case of $\alpha-SiC-ZrB_2$ composites containing above 39vol.% $ZrB_2$ showed positive temperature coefficient resistance(PTCR), whereas the electrical resistivity of $\alpha-SiC-21vol.% ZrB_2$ showed negative temperature coefficient resistance(NTCR).

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$\beta-SiC+39vol.%TiB_2$ 복합체의 전기저항률 (Electrical Resistivity of the $\beta-SiC+39vol.%TiB_2$ Composites)

  • 박미림;황철;신용덕;이동윤
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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    • pp.15-18
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    • 2001
  • The composites were fabricated 61 vol% $\beta$-SiC and $39vol%TiB_2$ powders with the liquid forming additives of 8, 12, 16wt% $Al_2O_3+Y_2O_3$ by hot pressing at $1730^{\circ}C$ and subsequent pressed annealing and pressureless annealing at $1750^{\circ}C$ for 4 hours to form YAG. The result of phase analysis of composites by XRD revealed $\alpha$-SiC(6H), $TiB_2$, and YAG($Al_5Y_3O_{12}$) crystal phase. The relative density of composites were increased with increasing $Al_2O_3+Y_2O_3$ contents. The fracture toughness showed the highest value of $7.77MPa{\cdot}m^{1/2}$ for composites added with 12wt% $Al_2O_3+Y_2O_3$ additives at room temperature. The electrical resistivity and the resistance temperature coefficient showed the lowest of $7.3{\times}10^{-4}{\Omega}{\cdot}cm$ and $3.8{\times}10^{-3}/^{\circ}C$, respectively, for composite added with 12wt% $Al_2O_3+Y_2O_3$ additives at room temperature. The electrical resistivity of the composites was all positive temperature coefficient resistance(PTCR) in the temperature range of $25^{\circ}C$ to $700^{\circ}C$.

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The Development of an Electroconductive SiC-ZrB2 Ceramic Heater through Spark Plasma Sintering

  • Ju, Jin-Young;Kim, Cheol-Ho;Kim, Jae-Jin;Lee, Jung-Hoon;Lee, Hee-Seung;Shin, Yong-Deok
    • Journal of Electrical Engineering and Technology
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    • 제4권4호
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    • pp.538-545
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    • 2009
  • The SiC-$ZrB_2$ composites were fabricated by combining 30, 35, 40 and 45vol.% of Zirconium Diboride (hereafter, $ZrB_2$) powders with Silicon Carbide (hereafter, SiC) matrix. The SiC-$ZrB_2$ composites, the sintered compacts, were produced through Spark Plasma Sintering (hereafter, SPS), and its physical, electrical, and mechanical properties were examined. Also, the thermal image analysis of the SiC-$ZrB_2$ composites was examined. Reactions between $\beta$-SiC and $ZrB_2$ were not observed via X-Ray Diffractometer (hereafter, XRD) analysis. The relative density of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$, and SiC+45vol.%$ZrB_2$ composites were 88.64%, 76.80%, 79.09% and 88.12%, respectively. The XRD phase analysis of the sintered compacts demonstrated high phase of SiC and $ZrB_2$ but low phase of $ZrO_2$. Among the SiC-$ZrB_2$ composites, the SiC+35vol.%$ZrB_2$ composite had the lowest flexural strength, 148.49MPa, and the SiC+40vol.%$ZrB_2$ composite had the highest flexural strength, 204.85MPa, at room temperature. The electrical resistivities of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$ and SiC+45vol.%$ZrB_2$ composites were $6.74\times10^{-4}$, $4.56\times10^{-3}$, $1.92\times10^{-3}$, and $4.95\times10^{-3}\Omega{\cdot}cm$ at room temperature, respectively. The electrical resistivities of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$ SiC+40vol.%$ZrB_2$ and SiC+45[vol.%]$ZrB_2$ composites had Positive Temperature Coefficient Resistance (hereafter, PTCR) in the temperature range from $25^{\circ}C$ to $500^{\circ}C$. The V-I characteristics of the SiC+40vol.%$ZrB_2$ composite had a linear shape. Therefore, it is considered that the SiC+40vol.%$ZrB_2$ composite containing the most outstanding mechanical properties, high resistance temperature coefficient and PTCR characteristics among the sintered compacts can be used as an energy friendly ceramic heater or electrode material through SPS.

SiC-ZrB2복합체의 특성에 미치는 SPS의 압력영향 (Effects of Pressure on Properties of SiC-ZrB2 Composites through SPS)

  • 이정훈;진범수;신용덕
    • 전기학회논문지
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    • 제60권11호
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    • pp.2083-2087
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    • 2011
  • The SiC-$ZrB_2$ composites were produced by subjecting a 40:60 vol.% mixture of zirconium diboride($ZrB_2$) powder and ${\beta}$-silicon carbide (SiC) matrix to spark plasma sintering(SPS). Sintering was carried out for 60sec at $1400^{\circ}C$ (designation as TP145 and TP146), $1500^{\circ}C$(designation as TP155 and TP156) and uniaxial pressure 50MPa, 60MP under argon atmosphere. The physical, electrical, and mechanical properties of the SiC-$ZrB_2$ composites were examined. The relative density of TP145, TP146, TP155 and TP156 were 94.75%, 94.13%, 97.88% and 95.80%, respectively. Reactions between ${\beeta}$-SiC and $ZrB_2$ were not observed via x-ray diffraction (hereafter, XRD) analysis. The flexural strength, 306.23MPa of TP156 was higher than that, 279.42MPa of TP146 at room temperature, but lower than that, 392.30MPa of TP155. The properties of a SiC-$ZrB_2$ composites through SPS under argon atmosphere were positive temperature coefficient resistance (hereafter, PTCR) in the range from $25^{\circ}C$ to $500^{\circ}C$. The electrical resistivities of TP145, TP146, TP155 and TP156 were $6.75{\times}10^{-4}$, $7.22{\times}10^{-4}$, $6.17{\times}10^{-4}$ and $6.71{\times}10^{-4}{\Omega}{\cdot}cm$ at $25^{\circ}C$, respectively. The densification of a SiC-$ZrB_2$ composite through hot pressing depend on the sintering temperature and pressure. However, it is convinced that the densification of a SiC-$ZrB_2$ composite do not depend on sintering pressure under SPS.

SPS on/off Pulse Time 조건에 따른 SiC-$ZrB_2$ 복합체 특성 (Properties of a SiC-$ZrB_2$ Composite by condition of SPS on/off Pulse Time)

  • 신용덕;주진영;이희승;박진형;김인용;김철호;이정훈
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.314-314
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    • 2010
  • The SiC-$ZrB_2$ composites were fabricated by combining 40vol.% of Zirconium Diboride(hereafter, $ZrB_2$) powders with Silicon Carbide(hereafter, SiC) matrix. TheSiC+40vol.%$ZrB_2$ composites were manufactured through Spark Plasma Sintering(hereafter, SPS) under argon atmosphere, uniaxial pressure of 50MPa, heating rate of $100^{\circ}C$/min, sintering temperature of $1,500^{\circ}C$ and holding time of 5min. But one on/off pulse sequence(one pulse time: 2.78ms) is 10:9(hereafter, SZ10), and the other is 48:8(hereafter, SZ48). The physical and mechanical properties of the SZ12 and SZ48 were examined. Reactions between $\beta$-SiC and $ZrB_2$ were not observed via X-Ray Diffraction(hereafter, XRD) analysis. The apparent porosity of the SZ10 and SZ48 composites were 9.7455 and 12.2766%, respectively. The SZ10 composite, 593.87MPa, had higher flexural strength than the SZ48 composite, 324.78MPa, at room temperature. The electrical properties of the SiC-$ZrB_2$ composites had Positive Temperature Coefficient Resistance(hereafter, PTCR).

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Ca 첨가가 PTCR 써미스터의 전기적 특성에 미치는 영향 (The Effects of Ca Addition on Electrical Properties of PTCR Thermistor)

  • 김병수;김종택;김철수;김용혁;이덕출
    • 한국전기전자재료학회논문지
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    • 제11권2호
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    • pp.121-127
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    • 1998
  • In this paper, to develop PTCR(Positive Temperature Coefficient of Resistance) thermistor with high withstanding voltage, Ca were added to. the compositions of $(Ba_{0.9165-X}-Sr_{0.08}-Ca_X-Y_{0.0035})TiO_3+MnO_2$ 0.02wt%+$SiO_2$ 0.5wt%. the effects of Ca additions were researched according the increasing of Ca from 0[mol%] to 20[mol%], and the electrical properties were investigated. As increasing Ca additions from 0[mol%] to 20[mol%], the grain size of the specimens was reduced from 11.1[${\mu}m$] to 6.15[${\mu}m$], and also the sintered density was reduced from 5.43[$g/cm^3$] to 5.05[$g/cm^3$] and their the breakdown voltages were increased from 163[V/mm] to 232[V/mm]. It is shown that the breakdown voltage was increased with amount of Ca additions.

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