Papers by Author: Rui Qing Chu

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Authors: Zhi Jun Xu, Rui Qing Chu, S.C. Cui, Long Zhi Zhao, Jin Son Zhang
Abstract: Rectangular cavity perturbation method was used to measure microwave dielectric loss (MDL) during the solid state reaction synthesis of SrFeCo0.5Oy. In the process of solid state reaction, the dielectric loss is investigated under different temperatures. The phases of the samples synthesized at different temperatures were characterized by XRD. The variation of MDL with temperature illustrates that the phase transformation occurs. The reasons why the pure perovskite phase can be obtained by using microwave processing were also discussed.
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Authors: Yan Jie Zhang, Zhi Jun Xu, Rui Qing Chu, Ji Gong Hao, Guo Rong Li, Qing Rui Yin, Pei Ying Zhu, Xin Wu, Qing Jun Lu, Lei Ding
Abstract: Sr2Bi (4-x/3) Ti (5-x) VxO18 (x = 0.0-0.06) (SBTV) ceramics were prepared by a solid-state reaction method, and the ferroelectric and dielectric properties of the ceramics were investigated with respect to the amount of V deficiency. XRD analysis indicated that the oxide compounds were Aurivillius phases. The Curie temperature of SBTV ceramics was improved by doping of certain amount of V. The V deficiency also led to a steady increase in the density together with a decrease in the coercive field. For the ceramics with x = 0.06, the properties become optimum: d33 = 19 pC/N, Tc = 306oC, Ec = 43.7 KV/cm.
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Authors: Zh.J. Xu, Rui Qing Chu, Bao Shan Li, Guo Rong Li, Qing Rui Yin
Abstract: Pb(Mn1/3Nb2/3)O3-Pb(Ti,Zr)O3 (PMnN-PZT) powders were synthesized by a hybrid method of sol-gel and ultrasonic atomization. The study shows that the resulting powder is pure, homogeneous and possesses a reasonably fine particle size. It is also believed to be applicable to other materials that can be processed via the technique.
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Authors: Rui Qing Chu, Zhi Jun Xu, Guo Rong Li, Qing Rui Yin
Abstract: Sr4Bi4Ti7O24 (SBT7) ceramics were prepared. X-ray powder diffraction indicated that single layered perovskite ferroelectrics were obtained. The ferroelectric and dielectric properties of SBT7 ceramics were investigated. The results showed that Sr4Bi4Ti7O24 is piezoelectric material. The dielectric properties were measured as a function of temperature and two peaks were observed in the curve.
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Authors: Wei Li, Zhi Jun Xu, Rui Qing Chu, Peng Fu
Abstract: BaTiO3 ceramics doped with 1, 2, 3 and 4 mol% La were prepared by sol-gel method. The effects of La doping on structure and dielectric characteristics of Ba1−xLaxTiO3 were investigated. The results show that: All the powders calcined at 800°C were found to be perovskite structure with cubic phase. Ba1−xLaxTiO3 were sintered at 1300°C, phase transition behavior appeared from tetragonal phase to cubic phase with increasing La-doping level. As the doping concentration increases, the grain growth of the Ba1−xLaxTiO3 ceramics was controlled efficiently and Curie point shifted to lower temperature. The grain size decreased from 20μm with 0 mol% La doped to 0.5μm with 4 mol% La doped. The Curie point shift rate was 22 °C/ mol% with increasing La content. The dielectric constant of La doped Ba1−xLaxTiO3 ceramics increased with increasing La content and a maximum value of 8900 was attained with 4 mol% La doped.
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Authors: Ji Gong Hao, Zhi Jun Xu, Rui Qing Chu, Yan Jie Zhang, Qian Chen, Guo Rong Li, Qing Rui Yin, Na Chen, Min Cui
Abstract: Zr-doped Sr2Bi4Ti5O18 (SBTi) bismuth layer-structured ferroelectric ceramics were prepared and studied. XRD patterns revealed that all the ceramic samples were single phase compounds. SEM images showed that dense microstructures with uniform gain size were obtained in all samples. The effects of Zr4+ doping on the dielectric, ferroelectric and piezoelectric properties of SBTi ceramics were also investigated. It was found that Zr4+ dopant gradually decreased the Curie temperature (Tc), enhanced the remnant polarization (2Pr) and decreased the coercive field (Ec) of SBTi ceramics. Furthermore, the piezoelectric properties of the SBTi ceramics were improved by enlarging the content of Zr. The SBTi ceramics with 4 mol% of Zr4+ dopant exhibited good electrical properties: d33 = 21 pC/N, 2Pr = 14.3 μC/cm2, Tc = 251°C, εr = 376, tanδ = 1.8%.
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Authors: Zhi Jun Xu, Rui Qing Chu, S.C. Cui, Jin Son Zhang
Abstract: Mixed-conducting ceramic oxide SrFeCo0.5Oy powders were prepared by a citrate method, and the contributing factors to the formation of homogeneous fine powder with a pure perovskite-type structure were ascertained. The resulting powder is pure, homogeneous and possesses a reasonably fine particle size. Attempts were made to understand the synthesis process and it was confirmed that the method produces powder had greater composition uniformity, lower residual carbonate levels and smaller particle sizes.
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