Preparation of High-Conductive High-Temperature PTC Resistor Ba1-x SrxPb1+yO3+z

1992 ◽  
Vol 290 ◽  
Author(s):  
H. Nagamoto ◽  
H. Kagotani ◽  
T. Koya
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Perovskite Structure ◽  
Positive Temperature Coefficient ◽  
Preparation Condition ◽  
Positive Temperature ◽  
Ptcr Effect ◽  
Higher Temperature ◽  
Temperature Coefficient Of Resistivity ◽  
A Site

AbstractThe positive temperature coefficient of resistivity (PTCR) effect in Ba1-xSrxPb1+yO3+z has been systematically studied. The effect of the PTC resistivity was strongly influenced by the preparation condition. The PTCR effect in metallic-conducting BaPb1+yO3+z. is confirmed around 700 °C, and the temperature where the PTCR effect starts can be successfully shifted to higher temperature range by substituting strontium for the A-site barium. The magnitude of the PTCR effect was increased and the resistibility was reduced by the enhancement of the sintering. In addition to Pb(IV) in the perovskite structure, Pb(II) is detected at the grain boundary in the sintered body.

Semiconducting BaTiO3 ceramic prepared by low temperature liquid phase sintering

1998 ◽  
Vol 13 (3) ◽  
pp. 660-664 ◽  
Author(s):  
I. Zajc ◽  
M. Drofenik
Keyword(s):  
Liquid Phase ◽  
Grain Boundary ◽  
Sintering Temperature ◽  
Positive Temperature Coefficient ◽  
Liquid Phase Sintering ◽  
Positive Temperature ◽  
Sintering Aid ◽  
Ptcr Effect ◽  
Temperature Coefficient Of Resistivity ◽  
Temperature Liquid

Donor-doped BaTiO3 ceramics were prepared by adding PbO B2O3 SiO2 as a sintering aid. Semiconducting BaTiO3 was obtained at a sintering temperature of 1100 °C. The sintered samples exhibit the Positive Temperature Coefficient of Resistivity (PTCR) effect, which depends on the amount of liquid phase, the concentration of the donor-dopant, and the sintering temperature. The cold resistivity of the samples decreases when the sintering temperature increases. The increase of the grain boundary resistivity and hence of the cold resistivity at lower sintering temperatures was explained by applying the diffusion grain boundary layer model.

The Influence of Donor-Doped Content on PTCR Effect of (Ba1-xSmx)TiO3 Based Ceramics Prepared by the Reduction Sintering-Reoxidation Method

2014 ◽  
Vol 1015 ◽  
pp. 517-520
Author(s):  
Xu Xin Cheng ◽  
Zhao Xiong Zhao ◽  
Dong Xiang Zhou ◽  
Qiu Yun Fu
Keyword(s):  
Room Temperature ◽  
Positive Temperature Coefficient ◽  
Room Temperature Resistivity ◽  
Positive Temperature ◽  
Dopant Content ◽  
Reducing Atmosphere ◽  
Donor Dopant ◽  
Ptcr Effect ◽  
Temperature Coefficient Of Resistivity ◽  
Temperature Resistivity

We investigated the effect of the donor-doped content on the positive temperature coefficient of resistivity (PTCR) of (Ba1-xSmx)TiO3(BST) Based Ceramics that were sintered at 1300 °C for 30 min in a reducing atmosphere and re-oxidized at 850 °C for 1 h. The results indicated that the resistance jump first increased and then decreased with an increase of the donor-doped concentration. Moreover, the specimens achieved a low room temperature resistivity of 383.1 Ω·cm at a donor-doped content and exhibited a pronounced PTCR characteristics with a resistance jump of 3.1 orders of magnitude. Furthermore, the RT reisistivity of the samples reduced and increased with the increasing of the donor-dopant content in the range of 0.1−0.5 mol% Sm3+. In addition, the effect of the Sm3+-doped concentration on the grain size of the ceramics was investigated in our paper.

Positive temperature coefficient of resistivity effect in Pb-doped KnbO3

2002 ◽  
Vol 17 (12) ◽  
pp. 2989-2992 ◽  
Author(s):  
Irena Pribošič ◽  
Darko Makovec ◽  
Miha Drofenik
Keyword(s):  
Phase Transition ◽  
Temperature Coefficient ◽  
Ferroelectric Material ◽  
Positive Temperature Coefficient ◽  
Cubic Phase ◽  
Room Temperature Resistivity ◽  
Positive Temperature ◽  
Ptcr Effect ◽  
Temperature Coefficient Of Resistivity ◽  
Temperature Resistivity

KnbO3 is a ferroelectric material with a Curie temperature (TC) at 415°C, thus giving it the potential to be a material for high-temperature positive temperature coefficient of resistivity (PTCR) applications. In this study, we investigated the PTCR effect in donor-doped KnbO3 ceramics containing 0, 0.1, 0.2, and 0.3 mol% PbO. The donor-doped KnbO3 ceramics exhibited a PTCR anomaly with a relatively low room-temperature resistivity. The temperature of the tetragonal-to-cubic phase transition (TC) of the KnbO3 decreased with the amount of added PbO, while the orthorhombic-to-tetragonal phase transition (TOT) remained unchanged.

scholarly journals High-Temperature Dielectric Relaxation Behaviors in Mn3O4 Polycrystals

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4026 ◽  
Author(s):  
Songwei Wang ◽  
Xin Zhang ◽  
Rong Yao ◽  
Liguo Fan ◽  
Huaiying Zhou
Keyword(s):  
High Temperature ◽  
Dielectric Relaxation ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Thermally Activated ◽  
Dielectric Relaxations ◽  
Plasma Sintering ◽  
Ptcr Effect ◽  
Temperature Relaxation ◽  
Lower Temperature

High temperature dielectric relaxation behaviors of single phase Mn3O4 polycrystalline ceramics prepared by spark plasma sintering technology have been studied. Two dielectric relaxations were observed in the temperature range of 200 K–330 K and in the frequency range of 20 Hz–10 MHz. The lower temperature relaxation is a type of thermally activated relaxation process, which mainly results from the hopping of oxygen vacancies based on the activation energy analysis. There is another abnormal dielectric phenomenon that is different from the conventional thermally activated behavior and is related to a positive temperature coefficient of resistance (PTCR) effect in the temperature region. In line with the impedance analyses, we distinguished the contributions of grains and grain boundaries. A comparison of the frequency-dependent spectra of the imaginary impedance with imaginary electric modulus suggests that both the long range conduction and the localized conduction are responsible for the dielectric relaxations in the Mn3O4 polycrystalline samples.

Resistivity Control by Solid-State Reaction of Perovskite-Type Oxides

1994 ◽  
Vol 365 ◽  
Author(s):  
H. Nagamoto ◽  
H. Tanaka ◽  
T. Koya
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Positive Temperature Coefficient ◽  
Sintered Body ◽  
Molar Ratio ◽  
Log P ◽  
Positive Temperature ◽  
Ptcr Effect ◽  
A Site ◽  
Perovskite Type

ABSTRACTResistivity control has been conducted by solid–state reaction of two different perovskite–type oxides. One is La0.5Ba0.5CoO3−δ (LBC) which showed metallic conduction, and its resistivity, ρ was 10−3 Ω.cm at 20 °C. The other is Ba0.998Sb0.002TiO3 (BT) which showed positive temperature coefficient of resistivity (PTCR) effect. The sintered body of the mixiure of the two oxides did not show PTCR effect. The logarithm of the resistivity of the sintered body, log ρmix was expressed using the resistivity of LBC, ρLBC, the molar ratio of BT, x, and temperature dependent constant, α(T) aslog ρmix = (l–x) log PLBC + xα(T)which holds for 0 ≤ x ≤ 0.8 at the temperature ranging from 20 to 240° C ρmix changed by about 8 orders of magnitude at room temperature. X–ray diffraction analysis suggested that metal ions at the A–site move from one perovskite–type oxide to another and that the sintered body consisted of two perovskite–type oxides different from starting ones.

The Influence of Ba-Ti Ratio on the Electrical Properties and Microstructures of the BaM-0.007Sm0.007TiO3 Based Ceramics Fired in Reducing Atmosphere

2011 ◽  
Vol 415-417 ◽  
pp. 1032-1037
Author(s):  
Xu Xin Cheng ◽  
Dong Xiang Zhou ◽  
Qiu Yun Fu ◽  
Shu Ping Gong
Keyword(s):  
Electrical Properties ◽  
Room Temperature ◽  
Positive Temperature Coefficient ◽  
Room Temperature Resistivity ◽  
Positive Temperature ◽  
Reducing Atmosphere ◽  
Ptcr Effect ◽  
Temperature Coefficient Of Resistivity ◽  
Bst Ceramics ◽  
Better Than

Electrical properties, positive temperature coefficient of resistivity (PTCR), and microstructures of (Bam-0.007Sm0.007)TiO3(BST) with different Ba-site/Ti-site (A/B) ratio sintered in a reducing atmosphere and reoxidized in air are investigated. The results reveal that the room temperature resistivity of the semiconducting BST ceramics first decreases and then increases with increasing of A/B ratio (m), particularly when m is equal to 1.006, the semiconducting BST ceramics which have been sintered in a reducing atmosphere and reoxidized at 800°C exhibit significant PTCR effect with a resistance jumping ratio of 3 orders magnitude, and achieve a lower room temperature resisitivity of 80.8 Ω∙cm, in addition, the grain size distribution of the Ti-excess specimens is much better than that of the Ba-excess ones.

Complex Impedance Spectroscopy Studies of BaTiO3 Ceramic with 10% BaFe12O19 Substitution

2015 ◽  
Vol 1107 ◽  
pp. 14-19 ◽  
Author(s):  
Zainuddin Zalita ◽  
S.N. Anuar ◽  
Roslinda Shamsudin ◽  
M.N. Idris
Keyword(s):  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Complex Impedance ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Impedance Spectroscopy Study ◽  
Different Temperatures ◽  
Temperature Coefficient Of Resistivity ◽  
Lower Temperature ◽  
Spectroscopy Studies

Barium titanate with 10% barium ferrite substitution (BaTiO3-BaFe12O19) has been synthesized by the solid state reaction route. Formation of the BaFe12O19 phase confirmed its existence in the composite. Impedance spectroscopy study of the composite sample was performed at different temperatures of 25, 40, 80, 120 and 160 °C. BaFe12O19 substituted sample shows a single semicircle at lower temperature and two overlapped arcs at 120 and 160 °C due to grain and grain boundary. The impedance plots were fitted based on a parallel R-CPE circuit. The grain boundary resistance behaves like the positive temperature coefficient of resistivity (PTCR) for donor-doped BaTiO3 semiconductor. The highest capacitance is contributed by the grain boundary at 80 °C.

The Positive Temperature Coefficient of Resistivity Effect in (1-x)KNbO3-xBaGeO3 Based Ceramics

2012 ◽  
Vol 476-478 ◽  
pp. 1046-1049
Author(s):  
Tie Zhu Xu ◽  
Xing Wen Zhu ◽  
Min Gong ◽  
Sheng Wei Wang ◽  
Wen Zhong Jiang ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Electrical Properties ◽  
Temperature Coefficient ◽  
Ceramic Materials ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Structural And Electrical Properties ◽  
Ptcr Effect ◽  
Temperature Coefficient Of Resistivity ◽  
Minimum Resistance

(1-x)KNbO3-xBaGeO3 based PTCR ceramic materials are prepared using high purity K2CO3, Nb2O5, GeO2, Al2O3 and BaCO3 powders as starting materials, and the structural and electrical properties have been investigated. The results indicated that the samples doped with minute Ba as donor show excellent PTCR effect above the temperature of about 36°C. For the 0.40at% Ba-doped sample, the minimum resistance of 4.2×104Ω·cm, temperature coefficient (αk) of 24.37%/°C, PTCR anomaly lg(Rmax/Rmin) of 3.82 and transition temperature (Tmin) of 36°C are obtained.

The Influence of Donor-Doped Concentration on the PTCR Characteristics of the Ban-xSmxTiO3 Based Ceramics Sintered in Reducing Atmosphere

2014 ◽  
Vol 881-883 ◽  
pp. 1031-1034
Author(s):  
Xu Xin Cheng ◽  
Dong Xiang Zhou ◽  
Zhao Xiong Zhao ◽  
Qiu Yun Fu
Keyword(s):  
Electrical Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Positive Temperature Coefficient ◽  
Room Temperature Resistivity ◽  
Positive Temperature ◽  
Reducing Atmosphere ◽  
Ptcr Effect ◽  
Temperature Coefficient Of Resistivity ◽  
Temperature Resistivity

Positive temperature coefficient of resistivity (PTCR) effect and electrical properties of (Ban-xSmx)TiO3(BSMT ) samples with different Ba-site/Ti-site ratio (n) and various concentration of the donor-doped Sm3+(x) sintered in a reducing atmosphere and reoxidized in air are investigated. The results show that the room temperature resistivity (ρRT) of the semiconducting BSMT ceramics first decreases and then increases with increasing of concentration of the donor-doped Sm3+, especially whenxis 0.005 mol, the ρRTof the BSMT ceramics is the lowest. Moreover, the ρRTof the Ba-excess BSMT (n= 1.01) specimens reoxidized at 800 oC for 1 h after sintering at 1270 °C for 30 min in a reducing atmosphere is lower than the Ti-excess ones (n= 0.99), in addition, the ρRTof the BSMT specimens increases with an increase of both sintering temperature and reoxidized time.

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