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Li Y.,Hebei Polytechnic University | Qu Y.,Tianjin University of Technology | Zhang Q.,Hebei Polytechnic University | Wang R.,Tianjin Maritime Vocational Institute
Advanced Materials Research | Year: 2011

Ba0.62Sr0.38TiO3 ceramics of perovskite structure are prepared by solid reaction method with the addition of x wt% NiO and their dielectric properties are investigated. It is found that Ni 2+ can enter the B site in ABO3 perovskite when doping concentration is less than 0.6 wt%, whereafter, Ni2+ ions most segregates on the grain boundaries to inhabit the grain growth. Due to the decrease of grain size and the impurity, the dielectric constants are decreased. Decrease of dissipation factor is attributed to appearance of the oxygen vacancy and disappearance of the reduction of Ti4+ ion. It is concluded that the diffuse phase transition is linked to the adulteration of Ni2+. The disordering, mechanical stress in the grain and the oxygen vacancies are produced because of the adulteration of Ni2+, and the diffuse phase transition increases with the level of doping increasing, leading to that the peaks of dielectric constants becomes slower and flatter. Source


Li Y.,Hebei United University | Wang R.,Tianjin Maritime Vocational Institute | Ma X.,Hebei United University | Li Z.,Shijiazhuang University | And 2 more authors.
Materials Research Bulletin | Year: 2014

The dielectric properties and phase transition of Sm3+-doped BaZr0.2Ti0.8O3 (BZT20) ceramics were investigated. Room temperature X-ray diffraction study suggested that the compositions had single-phase cubic symmetry. Microstructure studies showed that the grain size decreased and that the Sm2O3 amount markedly affected the dielectric properties of BZT20. A dielectric constant of 5700 at 0.2 mol% Sm2O3 and a dissipation factor of only 0.0011 at 2 mol% Sm2O3 were observed, indicating that BZT20 had significant potential applications. Moreover, the dielectric constant, dissipation factor, phase-transition temperature, and maximum dielectric constant increased with increased Sm2O3 amount at ≤0.2 mol% Sm2O3 but decreased with increased Sm 2O3 amount at >0.2 mol% Sm2O3. © 2013 Elsevier Ltd. All rights reserved. Source


Zhang S.-H.,Beijing University of Technology | Zhang S.-H.,Tianjin Maritime Vocational Institute | Wu L.-S.,Beijing University of Technology | Zhou D.-S.,Beijing University of Technology | Qu C.-N.,Beijing University of Technology
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2012

Based on the online dynamic balance device principle, the design method of the embedded double-face online dynamic device is proposed. The balance disks can be disengaged from the spindle through a hydraulic system, and the rotation speed of the disengaged disks is kept steady and under the speed of the spindle through a friction torque. The system realization of signal acquisition, signal analysis and control, and hydraulic pressure are designed. The feasibility is proved by examples. Source


Li Y.,Hebei United University | Ma X.,Hebei United University | Wang R.,Tianjin Maritime Vocational Institute | Cui Z.,Hebei United University | And 3 more authors.
Advanced Materials Research | Year: 2012

Ba(Ti 0.95Sn 0.05) O 3 ceramics were prepared using BaCO 3, SnO 2 and TiO 2 et al as crude materials, La 2O 3 as dopant, and their dielectric properties are investigated. The morphology analysis of sintered samples was conducted by SEM. It is found that for 0.1 wt% La 2O 3 doped BTS5 ceramics sintered at 1290°C has the highest dielectric constant. It can also be seen that the samples sintered at 1260°C have higher dielectric loss, which can result from the existence of the pore. Meanwhile, in the terms of dielectric loss, 0.1 wt% La 2O 3 doped BTS5 ceramics has lower value and the dielectric loss is more stable with temperature varying. © (2012) Trans Tech Publications. Source


Li Y.,Hebei United University | Ma X.,Hebei United University | Li Z.,Shijiazhuang University | Wang R.,Tianjin Maritime Vocational Institute | And 2 more authors.
Ceramics International | Year: 2013

The dielectric properties and phase transition of Sm3+-doped BaSn0.1Ti0.9O3 (BTS10) ceramics were investigated. The amount of Sm2O3 greatly affected the dielectric properties of BTS10. A dielectric constant of 5500 with 0.6 mol% Sm2O3 and a dissipation factor of only 0.005 with 0.1 mol% Sm2O3 were assessed. The variation in the dielectric constant indicated that Sm3+ ion is mainly substituted for the A-site ions when x≤0.6 mol%, whereas it is mainly substituted for B-site ions when x exceeded 0.6 mol%. Meanwhile, the variation in the dissipation factor showed that a very small amount of Sm3+ occupied the B site when x≤0.1 mol%. The materials showed relaxor-like behaviour with a diffuse-type ferroelectric phase transition. The diffusivity increased when the amount of Sm2O3 is increased, which also implied that there should be a very small amount of Sm3+ occupying the B site when x≤0.1 mol%. © 2012 Elsevier Ltd and Techna Group S.r.l. Source

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