Authors: Wei Deng, Jin Feng Nie, Xi Xiao, Jian Cong Yuan, Bo Ping Zhang, Yuan Hua Lin
Abstract: High density BaTiO3 ceramics have been prepared by the addition of CuO-Bi2O3-B2O3 mixed oxide. The results indicate that the sintering temperature of BaTiO3 bulk can be decreased by about 300°C and high dielectric behavior can be remained. The CuO-Bi2O3-B2O3 additives can increase the breakdown strength, and leads to an obvious enhancement of the energy density, which is nearly 2 times of pure BaTiO3.
1146
Authors: Hai Tao Li, Bo Ping Zhang, Qian Li, Rong Hui Xu
Abstract: Li-doped (Na, K)NbO3 lead-free piezoelectric ceramics with nominal composition of [Li0.065(Na0.535K0.48)0.95]NbO3 were prepared by normal sintering method, and its phase structure, microstructure and electric properties were studied with a special emphasis on the influence of sintering temperature in the range of 950-1020 oC. The result of XRD analysis indicates that a polymorphic phase transition (PPT) separating orthorhombic and tetragonal phases was found at the temperature of 950 oC, whereby enhanced piezoelectric properties of d33=255 pC/N and kp= 44.5% were obtained although the density was low. Our study indicates that the importance of PPT for enhancing electric properties in niobate-based ceramics at low temperature.
1679
Authors: Cui Hua Zhao, Bo Ping Zhang, Yong Liu, Song Jie Li
Abstract: LixTixNi1-2xO (x =0, 10 and 20 at. %) thin films with 200 nm in thickness were deposited on
Pt/Ti/SiO2/Si (100) by a sol-gel spin-coating method. All samples have a uniform microstructure. The
grain sizes grew from 100 nm to 300 nm by co-doping Li and Ti. The LiTiNiO thin films consist of NiO,
NiTiO3 and Li2NiO2, while the Li-free thin films consist of NiO, NiTiO3 and NiTi0.99O3. The dielectric
properties of the LiTiNiO thin films improved obviously by co-doping Li and Ti, but excess Li increases
the amount of Li2NiO2 phase and decreases the dielectric properties. The dielectric constants at 100 Hz
for the Li0.1Ti0.1Ni0.8O and Li0.2Ti0.2Ni0.6O thin films are 506 and 388 respectively. Appropriate co-doping
contents of Li and Ti are important to obtain a high dielectric property.
1817
Authors: Yong Liu, Yuan Hua Lin, Bo Ping Zhang, Ce Wen Nan, Jing Feng Li
Abstract: Nanometer La2CuO4 particles have been prepared using chemical precipitation method. The
reaction mechanism, microstructure and phase composition of the samples were investigated by TG-DTA,
XRD, SEM. The XRD results showed that pure La2CuO4 phase can be obtained by calcining the
La-Cu-O-H precursor powders at 900 oC for 2 h, and the impurity phase will appear in the La2CuO4
ceramic as increasing the sintering temperature over 1200 oC. La2CuO4 ceramic samples sintered at 950
oC for 6 h exhibit good thermoelectric properties. Seebeck coefficient can reach 714 μV/K, and power
factor is about 2.33×10-5 W/mK2.
556
Authors: Ya Ru Zhang, Bo Ping Zhang, Yan Dong, Jing Feng Li
Abstract: Li and Ti co-doped NiO thin films with 200 nm in thickness were deposited onto Pt/Ti/SiO2/
Si(100) substrates using a sol-gel spin-coating method. The effect of Ti doping content on microstructure
and dielectric properties of Li0.10TixNi0.90-xO (x=5-20mol%) thin films was investigated. XRD results
showed that all the Li0.10TixNi0.90-xO thin films consisted of a mixture of NiO, Li2NiO2 and NiTiO3 oxides.
The intensities of the diffraction peaks for the NiTiO3 phase increased and those for NiO decreased with
increasing Ti content, suggesting that a part of NiO phase combined with Ti to form NiTiO3 phase. The
dielectric constants of all the Li0.10TixNi0.90-xO thin films at 102 Hz at room temperature ranged from 200
to 400 and increased with increasing Ti content. The frequency stability of the dielectric constant for the
Li0.10TixNi0.90-xO thin films was also improved greatly with increasing Ti content.
2639
Authors: Yan Dong, Bo Ping Zhang, Ya Ru Zhang, Jing Feng Li
Abstract: LiTiNiO thin films were deposited on Pt/Ti/SiO2/Si(100) substrates using a sol-gel spin-coat
method. The effects of annealing temperature and annealing time on microstructures and dielectric
properties of the thin films were investigated. SEM images showed the thin films had uniform and dense
microstructure and the grain size increased with increasing temperature and time. The LiTiNiO thin films
consisted of complex oxides which proportions were mainly dependent on the annealing condition. The
LiTiNiO thin film annealed at 600°C for 1h showed the highest dielectric constant and frequency stability,
while prolonging annealing time even at 600°C resulted in the decrease in the frequency stability of the
dielectric constants.
2635
Authors: Yun Zhang, Bo Ping Zhang, Li Shi Jiao, Xiang Yang Li, Hiroshi Masumoto, Takashi Goto
Abstract: Au/SiO2 nano-composite multilayer thin films with different thickness were prepared on a
quartz substrate by magnetron plasma sputtering. The microstructure, morphology and optical properties
of the films were investigated by using TEM and optical absorption spectra. [Au/SiO2]×5 and [Au/SiO2] ×
11 multilayer thin films have well-defined interface. The thickness of the multilayer was 60nm and 130
nm for the thin films with 5 and 11 layers, respectively. The optical absorption peaks due to the surface
plasma resonance appeared at a wavelength of 560 nm for the both [Au/SiO2]×5 and [Au/SiO2]×11 thin
films. The intensity of the absorption peak increased with increasing numbers of deposition layers. The
optical absorption spectra of Au/SiO2 multilayer thin films are well agreement with the theoretical optical
absorption spectra calculated from rewritten Maxwell–Garnett effective medium theory.
2575
Authors: Wei Shu Liu, Bo Ping Zhang, Jing Feng Li, Heng Wang
Abstract: Single-phase polycrystalline CoSb3 skutterudite was prepared through a new combination of
mechanical alloying (MA) and spark plasma sintering (SPS). In order to investigate the influence of MA
conditions on the microstructure and thermoelectric properties, MA synthesis were carried out under
various conditions with different milling times. The powder sample MAed for 6h still consisted of metal
Sb, and then transformed to CoSb3 with a little amount of metal Sb and CoSb2 phases after MA for 15h.
Further prolonging the MA time resulted in the decomposition of CoSb3 to CoSb2 phase. The average
grain size of the SPSed samples decreased from 650nm to 250nm as MA-time was prolonged from 6 to
24h. Lattice parameters estimated form XRD patterns increase with the increasing MA time. All samples
SPSed at 600°C for holding 5 min show an n-type conduction. The electrical resistivity was 1030, 895,
410, 260 μm for the samples from the MA-derived powders with MA-time of 6, 15, 24 and 33h at room
temperature, respectively, then reduced to 60 μm at 400°C for all samples. An optimum MA time is 24
h in which the sample shows the highest power factor 612μW/m*K2 at 150°C.
834
Authors: Ke Wang, Bo Ping Zhang, Jing Feng Li, Hong Jin Liu
Abstract: Highly dense Na1-xKxNbO3 (x=0.2~0.8) ceramics were successfully prepared using spark
plasma sintering (SPS) at temperature as low as 920°C. Solid solutions were formed during the
composition range investigated. The piezoelectric constant and planar mode electromechanical coupling
coefficient are significantly dependent on the Na/K ratio, with the maximum value of 148 pC/N and
38.9% at the composition Na0.5K0.5NbO3.
224
Authors: Peng Xi Li, Bo Ping Zhang, Jing Yi Chen, Yi Fan Tu
Abstract: AZ31B Magnesium alloy sheets with about 1 mm in thickness were rolled by one pass
and several passes from the extruded ingots with different thickness. The effects of processing
variables on microstructure and mechanical properties of AZ31B Mg alloy sheets were investigated.
XRD indicated that AZ31B magnesium alloy sheets have a dominant texture with (000l) orientated
plane. The large deformation results in the formation of fine and homogeneous microstructure due
to the recrystallization during extruding and hot-rolling. The thinnest sheet rolled by several passes
showed equiaxed grains with 5-10μm in diameter. The fine grains result in the increase in the
strength and the ductility. The tensile strength of the sheet rolled by several passes reached 292
MPa and the elongation was twice as larger as that rolled by one pass.
653