Papers by Author: Bao Shan Li

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Authors: Bao Shan Li, Guo Rong Li, Zhi Gang Zhu, Wang Zhong Zhang, Qing Rui Yin, Ai Li Ding
Abstract: This paper aims at the determination of the effects of strontium addition on the microstructural evolution and the piezoelectric properties for Pb(Mn1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMnN-PZT) ceramics. The Sr content was chosen in the range of 2-8 mol%. These materials were prepared by the solid phase reaction of the oxides. It was found, from the experimental results, the tetragonality of the PMnN-PZT lattice and the Curie temperature decreased with Sr content; in the meantime, dielectric constant increased greatly. Dielectric constant (er) and planar coupling factor (Kp) was proven to be dependent on sintering temperature. P-E curves of PMnN-PZT system exhibited some “pinched” shape instead of the normal square-like P-E loops, illustrating presence of the oxygen vacancies by reason of the preferable substitution of the B-sites ion.
Authors: Zhi Gang Zhu, Bao Shan Li, Guo Rong Li, Qing Rui Yin
Abstract: The effects of SiO2 additives on microstructure, piezoelectric and mechanical properties were investigated for Pb0.98Sr0.02(Mn1/3Sb2/3)0.05Zro.48Ti0.47O3 (PMS-PZT) ternary system close to the morphotropic phase boundary. Piezoelectric coefficient (d33) and electromechanical coupling factor (Kp) considerably deteriorated with the substitution of SiO2 increased. On the other hand, the mechanical quality factor (Qm) increased, the maximum value was 1800. Fracture strength of 1.0 wt% SiO2 added the specimens reached to 106.54 MPa which was about 1.4 times higher than pure PMS-PZT ceramic. The rapid improvement of fracture strength probably due to the decrease of grain size, pore distribute and the second phase (redundant Si4+ ions) segregating on the grain boundary which enhanced the bond energy of grain boundary. The optimized concentration of SiO2 doped PMS-PZT ceramics was 0.4 wt% for high power application: d33 = 300 PC/N, Kp = 0.51, Qm = 1500, tand = 0.32% and the fracture strength was 88.5MPa.
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.
Authors: Zhi Gang Zhu, Bao Shan Li, Guo Rong Li, Xiang Ping Jiang, Qing Rui Yin
Abstract: The use of lead zirconate titanate ceramics for high power application must have superior mechanical properties, the composition Pb0.98Sr0.02(Mn1/3Sb2/3)0.05Zro.48Ti0.47O3 + x wt% SiO2 (x = 0-1.0) have been studied for this purpose. The microstructures were observed to study the improvement of mechanical properties by SEM and TEM. The nano-scale secondary phase of SiO2 and PbSiO3 were observed on the grain boundary and the twinned ZrO2 was found surrounded by PMS-PZT perovskite phase. The mechanism to the occurrence of twinned ZrO2 and its content increased with increasing Si concentration are discussed in the paper. The occurrence of the nonferroelectric phase such as ZrO2, SiO2 and PbSiO3 on the grain boundary should be the main reason for great improvement of fracture strength.
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