BaBiO3-doped BaTiO3 （BB-BT） ceramic, as a candidate for lead-free positive temperature coefficient of resistivity （PTCR） materials with a higher Curie temperature, has been synthesized in air by a conventional sin...BaBiO3-doped BaTiO3 （BB-BT） ceramic, as a candidate for lead-free positive temperature coefficient of resistivity （PTCR） materials with a higher Curie temperature, has been synthesized in air by a conventional sintering technique. The temperature dependence of resistivity shows that the phase transition of the PTC thermistor ceramic occurs at the Curie temperature, Tc = 155℃, which is higher than that of BaTiO3 （≤ 130 ℃）. Analysis of ac impedance data using complex impedance spectroscopy gives the alternate current （AC） resistance of the PTCR ceramic. By additional use of the complex electric modulus formalism to analyse the same data, the inhomogeneous nature of the ceramic may be unveiled. The impedance spectra reveal that the grain resistance of the BB-BT sample is slightly influenced by the increase of temperature, indicating that the increase in overall resistivity is entirely due to a grain-boundary effect. Based on the dependence of the extent to which the peaks of the imaginary part of electric modulus and impedance are matched on frequency, the conduction mechanism is also discussed for a BB-BT ceramic system.展开更多
A novel Na_(1−x)K_(x)TaO_(3)(x=0,0.025,0.05,0.075,0.1,and 0.15)ceramic with high permittivity and high positive temperature coefficient was synthesized via the conventional solid-state method.All samples were determin...A novel Na_(1−x)K_(x)TaO_(3)(x=0,0.025,0.05,0.075,0.1,and 0.15)ceramic with high permittivity and high positive temperature coefficient was synthesized via the conventional solid-state method.All samples were determined to be pure phase orthorhombic NaTaO3 structure of space group Pmcn,and larger grain and lower porosity were observed after adding an appropriate amount of K+ions.The Q×f value is majored by the packing fraction and grain size,while the value ofτf is influenced by Ta–O bond valence.The Na_(0.95)K_(0.05)TaO_(3) ceramic possesses excellent dielectric properties ofεr=164.29,Q×f=9091 GHz(f=3.15 GHz),tanδ=3.46×10^(–4),τf=+809.52 ppm/℃,sintered at 1550℃.Compared with NaTaO_(3) ceramics,the Na_(1−x)K_(x)TaO_(3)ceramics prepared in this study demonstrate higher dielectric constants and higher positive temperature coefficients,which are promising for device miniaturization andτf compensators.展开更多
正温度系数(positive temperature coefficient,PTC)热敏陶瓷是一类关键电子功能陶瓷,因其优异的特性在加热元件、传感器、电路保护器、温度控制器、电器消磁等领域都有广泛的应用。BaTiO_(3)作为主体材料制备的正温度系数热敏电阻(posi...正温度系数(positive temperature coefficient,PTC)热敏陶瓷是一类关键电子功能陶瓷,因其优异的特性在加热元件、传感器、电路保护器、温度控制器、电器消磁等领域都有广泛的应用。BaTiO_(3)作为主体材料制备的正温度系数热敏电阻(positive temperature coefficient thermistor,PTCR)是目前用量较大的一类正温度系数元件,具有重要的研究意义。本文阐述了正温度系数热敏材料的分类及其优缺点,介绍了正温度系数效应、热敏机理及BaTiO_(3)基正温度系数材料的半导化原理,综述了BaTiO_(3)基正温度系数热敏陶瓷国内外研究现状,分析了移峰剂、施主掺杂、受主掺杂、烧结工艺等因素对BaTiO_(3)基正温度系数热敏陶瓷的影响,总结了正温度系数热敏元器件的应用原理及其在相关领域的应用,并对正温度系数热敏陶瓷的无铅化进行了展望。展开更多
分析了现有短路电流限制技术的发展现状,提出一种基于正温度系数(positive temperature coefficient,PTC)热敏电阻的可恢复型混合式短路限流装置的拓扑结构。通过将PTC热敏电阻与超快速分断开关并联,有效提高了限流装置的额定通流能力,...分析了现有短路电流限制技术的发展现状,提出一种基于正温度系数(positive temperature coefficient,PTC)热敏电阻的可恢复型混合式短路限流装置的拓扑结构。通过将PTC热敏电阻与超快速分断开关并联,有效提高了限流装置的额定通流能力,并充分利用PTC材料的电阻快速变化特性,提高装置限流能力,降低限流装置对于PTC材料额定通流要求。给出该型限流装置的检测判断原理及控制策略,分析其限流过程。完成基于PTC热敏电阻的混合式短路限流装置应用于蓄电池组电源短路限流的试验测试,通过不同设定电流值时的限流试验结果,证明所设计的装置能快速有效限制短路电流,具有良好的应用前景。展开更多
基金supported by the Research Funds of the Guangxi Key Laboratory of Information Materials at the School of Material Science and Engineering,China (Grant No. 0710908-07-Z)
文摘BaBiO3-doped BaTiO3 （BB-BT） ceramic, as a candidate for lead-free positive temperature coefficient of resistivity （PTCR） materials with a higher Curie temperature, has been synthesized in air by a conventional sintering technique. The temperature dependence of resistivity shows that the phase transition of the PTC thermistor ceramic occurs at the Curie temperature, Tc = 155℃, which is higher than that of BaTiO3 （≤ 130 ℃）. Analysis of ac impedance data using complex impedance spectroscopy gives the alternate current （AC） resistance of the PTCR ceramic. By additional use of the complex electric modulus formalism to analyse the same data, the inhomogeneous nature of the ceramic may be unveiled. The impedance spectra reveal that the grain resistance of the BB-BT sample is slightly influenced by the increase of temperature, indicating that the increase in overall resistivity is entirely due to a grain-boundary effect. Based on the dependence of the extent to which the peaks of the imaginary part of electric modulus and impedance are matched on frequency, the conduction mechanism is also discussed for a BB-BT ceramic system.
基金supported by the National Key R&D Program(No.2022YFB2807405)the Natural Science Foundation of Sichuan Province(No.2022NSFSC1959)the Open Foundation of National Engineering Research Center of Electromagnetic Radiation Control Materials(No.ZYGX2020K009-1).
文摘A novel Na_(1−x)K_(x)TaO_(3)(x=0,0.025,0.05,0.075,0.1,and 0.15)ceramic with high permittivity and high positive temperature coefficient was synthesized via the conventional solid-state method.All samples were determined to be pure phase orthorhombic NaTaO3 structure of space group Pmcn,and larger grain and lower porosity were observed after adding an appropriate amount of K+ions.The Q×f value is majored by the packing fraction and grain size,while the value ofτf is influenced by Ta–O bond valence.The Na_(0.95)K_(0.05)TaO_(3) ceramic possesses excellent dielectric properties ofεr=164.29,Q×f=9091 GHz(f=3.15 GHz),tanδ=3.46×10^(–4),τf=+809.52 ppm/℃,sintered at 1550℃.Compared with NaTaO_(3) ceramics,the Na_(1−x)K_(x)TaO_(3)ceramics prepared in this study demonstrate higher dielectric constants and higher positive temperature coefficients,which are promising for device miniaturization andτf compensators.
文摘正温度系数(positive temperature coefficient,PTC)热敏陶瓷是一类关键电子功能陶瓷,因其优异的特性在加热元件、传感器、电路保护器、温度控制器、电器消磁等领域都有广泛的应用。BaTiO_(3)作为主体材料制备的正温度系数热敏电阻(positive temperature coefficient thermistor,PTCR)是目前用量较大的一类正温度系数元件,具有重要的研究意义。本文阐述了正温度系数热敏材料的分类及其优缺点,介绍了正温度系数效应、热敏机理及BaTiO_(3)基正温度系数材料的半导化原理,综述了BaTiO_(3)基正温度系数热敏陶瓷国内外研究现状,分析了移峰剂、施主掺杂、受主掺杂、烧结工艺等因素对BaTiO_(3)基正温度系数热敏陶瓷的影响,总结了正温度系数热敏元器件的应用原理及其在相关领域的应用,并对正温度系数热敏陶瓷的无铅化进行了展望。
文摘分析了现有短路电流限制技术的发展现状,提出一种基于正温度系数(positive temperature coefficient,PTC)热敏电阻的可恢复型混合式短路限流装置的拓扑结构。通过将PTC热敏电阻与超快速分断开关并联,有效提高了限流装置的额定通流能力,并充分利用PTC材料的电阻快速变化特性,提高装置限流能力,降低限流装置对于PTC材料额定通流要求。给出该型限流装置的检测判断原理及控制策略,分析其限流过程。完成基于PTC热敏电阻的混合式短路限流装置应用于蓄电池组电源短路限流的试验测试,通过不同设定电流值时的限流试验结果,证明所设计的装置能快速有效限制短路电流,具有良好的应用前景。
