Authors: Yan An Wang, Xiang Feng Guan, He Ping Zhou, Ying He
Abstract: GdSrCoO3-δ and Gd1-XSrXCoO3-δ (x=0.1~0.5) were synthesized using glycine-nitrate process
(GNP). The formation process of perovskite phase and microstructure of powders were characterized
using TG-DTA and XRD. All the powders with different doping amounts of Sr2+ on A-site were
single-phase solid solutions, and the stable perovskite phase was formed completely after calcination at
1100°C. The crystal structures of the solid solutions transfer to a higher symmetrical perovskite.
268
Authors: Xiang Feng Guan, Yan An Wang, He Ping Zhou, Li Hua Zhou
Abstract: A citrate gel method was applied to synthesize Ce0.8Sm0.2O1.9 powders by using cerium and
samarium nitrates as raw materials and citric acid as complexing agent. It was shown that Ce0.8Sm0.2O1.9
phase was formed when the decomposition of the dried gel completed at 500 °C. The crystallite size of the
synthesized powders calcined at 500 °C for 2 h is 5-10 nm. The powders can be easily sintered in air to
yield over 97 % relative density at 1250 °C, which is significantly lower than sintering temperature of
over 1500°C required by the doped ceria powders prepared via conventional ceramic techniques.
247
Authors: Ying He, He Ping Zhou, Han Feng Wang
Abstract: The cordierite powders have been synthesized by low temperature combustion technique using
urea as fuel, nitrates as oxidizer and silicic acid as silica source. The sintering behavior and crystallization
process were investigated. The results showed that the powders could be sintered at a temperature lower
than 1000 °C. The μ-cordierite crystallized from glass at first, and then transformed into α-cordierite at
higher temperature. The obtained cordierite based glass ceramics at different temperatures have low
dielectric constant (4.16 ~ 5.02 at 1 MHz) and low dielectric dissipation factor (≈ 0.003 at 1 MHz) as well
as low temperature sintering behavior, which is compatible for electronic packaging.
192
Authors: Chun Lai Xu, He Ping Zhou
Abstract: Ba0.5Sr0.5TiO3 (BSTO) ceramics were synthesized by spark plasma sintering (SPS) technique.
The phase compositions, microstructure and dielectric properties of BSTO ceramics were investigated.
The results indicated that SPS was an alternative sintering technology to synthesize dense BSTO
ferroelectric ceramics at low temperature and in a short period.
59
Authors: Shao Xin Zhou, Dan Liu, He Ping Zhou, Zhong Bo Hu, Yong Mei Hao
Abstract: The spark plasma sintering technique was used to fabricate ceramics from Pb(Mg1/3Nb2/3)O3–
PbTiO3 ceramic layers which were prepared by tape casting and TGG method used BaTiO3 templates as
seeds. During heat treatment, epitaxial grain growth occurred on the BaTiO3 surfaces and formed <001>
textured lead magnesium niobate-lead titanate, Pb(Mg1/3Nb2/3)O3-0.325PbTiO3 (PMN-32.5PT) ceramics.
The phase compositions and microstructure were investigated. The results indicated that this method was
an alternative sintering technology to synthesize dense lead-based relaxor ferroelectric ceramics.
27
Authors: Dan Liu, Yong Ke Yan, He Ping Zhou
Abstract: <001> textured 0.675Pb(Mg1/3Nb2/3)O3-0.325PbTiO3 (PMN-32.5PT) ceramics were prepared
by templated grain growth with micron scale BaTiO3 platelet templates. 0%~7% excess PbO was added
to form liquid phase. The influence of liquid phase concentration on the growth of matrix and templated
grains was investigated. The growth process was controlled by a dissolution-precipitation mechanism.
The templated grain growth was accelerated by the formed liquid phase and resulted in highly textured
PMN-32.5PT ceramics.
15
Authors: Xiang Feng Guan, Zhi Hui Liu, He Ping Zhou
Abstract: Nanosized Ce0.8Gd0.05Y0.15O1.9 powders were synthesized using glycine nitrate process for use
as the electrolyte of intermediate temperature solid oxide fuel cells. The powders were characterized by
simultaneous thermogravimetry analysis (TGA) and differential thermal analysis (DTA), X-ray powder
diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
The XRD pattern indicated that the powders exhibited a single phase with cubic fluorite structure. The
TEM studies showed that the calcined powders exhibited an almost spherical morphology and the mean
size of the particles was 30nm, which is in agreement with the calculated result of XRD.
2005
Authors: Han Feng Wang, He Ping Zhou
Abstract: The effects of Li+ addition on the sintering and microstructural evolution of cordierite were
analyzed. As nucleating agent, the Li+ additive decreased the expansion coefficient and dielectric
constant. The doping of Li+ was found to block the phase transition from μ-cordierite to α-cordierite and
increase sintering temperatures. The effect of Li+ on the activation of cordierite can be attributed to the
nucleation of cordierite. Too much Li+ will inhibit the cordierite crystallization and encourage
amblygonite crystallization. Cordierite powders were prepared by sol-gel processing.
1859
Authors: Yu Zhen Zhao, Jun Zhang, He Ping Zhou
769
Authors: Zhi Hui Liu, Xiang Feng Guan, He Ping Zhou
Abstract: Ceria electrolytes co-doped with Gd3+ and Y3+ (Ce0.8Gd0.2-xYxO1.9) were synthesized by GNP.
The crystal structures, lattice parameters and crystallite sizes were determined by XRD. The morphology
of the powders was observed by TEM. Sintered at 1250oC for 4 h, all die-pressed ceria pellets achieved
densities higher than 95% of theoretical values. The ionic conductivities were measured using AC
impedance technique and Ce0.8Gd0.05Y0.15O1.9 showed a higher ionic conductivity than those of other
compositions at 500-750oC, indicating that it is an attractive electrolyte material for IT-SOFC.
395