bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Absorption Capability of 3D Braided-Textile Composite Tubes with Rectangular Cross Section
Authors: Yang Yu Qiu , Nakai Asami , Uozumi Tadashi , Hamada Hiroyuki
Published: March 2009

Fiber Reinforced Plastics (FRPs) are now under research as crush element because of its
contribution in energy absorption. The 3D-textile braiding was introduced in this study as a
reinforcement form of fibers. The CFRP square tubes with rectangular cross section were tested in
quasi-static experiments. The results show that 3D structure was effective in holding back the
propagation of the central crack and the composite tube with a design on the corners could perform
better energy absorption capability.
Effect of Yttria Nanopowder on Multi-Layer Coatings of Yttria And CVD SiC/Graphite
Authors: Zhang Xian , Cheng Lai Fei , Zhang Li Tong , Wu Shou Jun , Xu Yong Dong
Published: March 2009

Nano-yttria powder can be synthesized by yttrium citrate-urea precursor, combusted at
600°C in air. The CVD SiC coated on graphite (CVD SiC/Graphite) infiltrated by the yttrium
citrate-urea precursor, combusted at of 600°C, and then sintered at 1450°C, the thin yttria film can
be achieved. The SEM morphology and EDS result of the thin yttria film show a mass of
needle-shaped pining into the CVD SiC layer, which improves the combination of CVD SiC
layer and wash yttria coating. Therefore, it is an effective transition layer between CVD SiC
coating and wash yttria layer.
Nano-Mechanical Properties of Coiled Carbon Nanotube Reinforced Epoxy Composites
Authors: Li Xiao Feng , Lau Alan Kin Tak , Yin Yan Sheng
Published: March 2009

The applications of carbon nanotubes benefit to a wide range of engineering, applied
physics and biomaterials areas for their superior mechanical and electrical properties. Recently,
coiled carbon nanotube (CCNT) has opened a new alternative to reinforce traditional advanced
composites. Their coiled shapes are considered to induce mechanical interlocking between the
nanotubes and matrix which result in the enhancement of fracture toughness and mechanical
strength of the composites. In this study, nanomechanical properties of CCNT reinforced epoxy
composites with varying weight percentages (0, 1, 3, and 5 wt %) of nanotubes were measured by
the nanoindentation technique. Hardness and elastic modulus measurement of the composites were
conducted.
Organoclay Effect on Transverse Tensile Strength and In-Plane Shear Strength of Unidirectional Glass/Epoxy Nanocomposites
Authors: Tsai Jia Lin , Wu Ming Dao
Published: March 2009

This research focuses on the fabrication of glass fiber/epoxy organoclay nanocomposites as
well as on the investigation of organoclay effect on transverse tensile strength and in-plane shear
strength of the nanocomposites. To demonstrate the organoclay effect, three different loadings of
organoclay were dispersed respectively in the epoxy resin using a mechanical mixer followed by
sonication. The corresponding glass/epoxy nanocomposites were produced by impregnating dry glass
fiber with organoclay epoxy compound via a vacuum hand lay-up procedure. For evaluating
transverse tensile strengths, the unidirectional coupon specimens were prepared and tested in the
transverse direction. Results indicate that with the increment of organoclay loadings, the glass/epoxy
nanocomposites demonstrate higher transverse tensile strength. On the other hand, the in-plane shear
strengths were measured from [± 45]s laminates. It is revealed that when the organoclay loadings
increase, the in-plane shear strength of glass/epoxy nanocomposites also increases appropriately.
Scanning Electron Microscopy (SEM) observations on the failure surfaces indicate that the increasing
characteristics in transverse and in-plane failure stresses may be ascribed to the enhanced fiber/matrix
bonding modified by the organoclay.
Electrical Resistance Response of Carbon Nanotube / PMMA / PVAc Composite Sensors to Organic Vapours at Low Vapour Concentrations
Authors: Zhao Dong Lin , Chai Hong Mei , Liu Yun Fang , Shen Zeng Min
Published: March 2009

Thin films of poly(methyl methacrylate) (PMMA)，poly(vinyl acetate) (PVAc) and
carbon nanotube composites were produced by different coating methods. The best way to produce
the carbon nanotube / PMMA / PVAc composite film with conductive network is dispersing carbon
nanotubes in PMMA and PVAc by ultrasonic and by solution casting. Electrical resistance
responses of carbon nanotube / PMMA / PVAc composite sensors against various organic vapors at
low concentrations are investigated. The experimental results indicate that the composites have high
selectivity to various organic vapors at the same concentration. In addition, the electric resistance
response of the composites against organic vapors takes place in step with their vapor adsorption
procedure. Compatible blends of poly(methyl methacrylate) and poly(vinyl acetate) would be a
good candidate to produce a series of electrically conducting carbon nanotubes composite film
whose resistance is sensitive to the nature and concentration of an analyte in the vapor phase. The
results indicate that the carbon nanotube / PMMA / PAVc composite film can be used as a novel
organic vapor sensor to detect, quantify and discriminate various organic vapors.
Simulation of Inelastic Stress - Strain Response of Nanocomposites by a Network Model
Authors: Zidek J. , Jancar Josef
Published: March 2009

This paper describes the viscoelastic properties of network model. In the first
approximation, nanocomposite was modeled as a 3D tetrafunctional network considering
entanglements to act as the physical x-links. Nano-sized non-deformable domains of defined shape
and size were introduced into the network. The chains in the vicinity of the inclusions were
considered immobilized. Hence, the semicrystalline polymer was considered a three-phase system
containing flexible matrix bulk phase, immobilized chains near the inclusion surface and rigid
crystalline domains. The crystallites were characterized by their Young's modulus and their traction
properties were calculated using the Hooke's law. Unlike the model, the real polymer has viscoelastic
deformation properties. The components which could cause viscoelastic properties were introduced
and their impact on viscoelastic properties of whole network was investigated. The components were
for example the reptation motion of chain in entanglements or chain, whose motion was retarded by
impact of surroundings. The model enabled to investigate the influence of each component, as well as
the influence of distribution of each component. The types of nods, whose influence was investigated
in this contribution, were fast knot, free entanglement, one-way entanglement and energy barrier.
Elasticity Solution of Laminated Cylindrical Shell with Piezoelectric Layer under Local Ring Load
Authors: Yas M.H. , Shakeri Morteza , Saviz M.R.
Published: March 2009

Elasticity solution is presented for simply-supported, orthotropic, piezoelectric
cylindrical shell with finite length under local ring load in the middle of shell and electrostatic
excitation. The highly coupled partial differential equations (p.d.e.) are reduced to ordinary
differential equations(o.d.e.) with variable coefficients by means of trigonometric function
expansion in longitudinal direction for displacement and external forces. The resulting ordinary
differential equations are solved by Galerkin finite element method. Numerical examples are
presented for [0/90/P] lamination with sensor and actuator for different thicknesses.
Colorful Emission from OLEDs of Porphyrin Doped MEH-PPV
Authors: Zhong Guo Lun , Wu Jun , Wang Yong Hong , Sun Jian Zhong , Wang Jin Hao , Xia Hai Ping
Published: March 2009

The properties of photoluminescence (PL) and electroluminescence (EL) of 5,10,15,20-
tetra-p-tolyl-21H, 23H-porphine (TTP) doped poly[2-methoxy-5-(2’-ethylhexyloxy)-1,4-
phenylenevinylene] (MEH-PPV) was studied in this paper. A multi-color emission from the
corresponding light-emitting device was observed.
Dielectric and Ferroelectric Properties of Bi-Doped BaTiO3 Ceramics
Authors: Jiang Xiang Ping , Zeng M. , Kowk K.W. , Chan Helen Lai Wah
Published: March 2009

Barium titanate with A-site substituted by various amount of bismuth oxide (Ba1-x
BixTiO3, abbreviated as BBT, x=0.05, 0.1, 0.15) were prepared by solid-state reaction. The
effect of bismuth substitution on crystallographic phase, dielectric and ferroelectric
properties was studied. The X-ray diffraction shows that the samples were crystallized into
pure perovskite structure when x=0.05 and 0.1, while for x=0.15 sample, second phase
appeared in the dominant perovskite phase. The temperature dependence of dielectric
permittivity of the ceramics was investigated and the evolution from normal ferroelectrics to
relaxor ferroelectric sates was observed. In the range 0≤x≤0.1, the temperature of dielectric
peak Tm is independence of the frequency, indicating the normal ferroelectrics behavior. At
x=0.15, dielectric relaxation process with a broadening distribution of the permittivity
dielectric is observed.
Polymer Composites as Gas Sensors with Molecular Discrimination Ability
Authors: Zeng Wei , Zhang Ming Qiu , Rong Min Zhi
Published: March 2009

To prepare a novel gas sensor being able to recognize molecules, waterborne
poly(β-cyclodextrin-block-polydiethylene glycol hexandioic ester) (i.e., waterborne
β-CD-block-PDEA) was synthesized and filled with carbon black (CB). It was found that the
composites’ electric resistance remarkably changed when the composites were exposed to the vapors
of small size molecule solvents (including dichloromethane, chloroform and tetrahydrofuran, etc.).
However, almost no response could be detected in the vapors of large size molecule solvents (like
n-pentane, ethylbenzene and hexane). Besides, the responsiveness gradually decreased with
increasing molecular size of organic solvents. The results evidenced that the composites have
acquired considerable selective sensitivity towards gaseous analytes in terms of their molecular sizes.
β-cyclodextrin rather than polydiethylene glycol hexandioic ester played the leading role in this
aspect, which was explained from the viewpoint of host-gust chemistry. That is, the response
mechanism is mainly based on the molecular discrimination behavior of the host compounds. The
small analytes could be entrapped by the β-cyclodextrin cavity due to van der Waals force. On the
other hand, solvents’ permittivity also played an important role. The molecules with high permittivity
were difficult to enter the hydrophobic cavities. The present study demonstrated the composites could
serve as candidates for gas sensors capable of molecule discrimination.
Preparation and Characterization of α-Fe2O3 Nanometer Particles of Different Appearance
Authors: Li Qiao Ling , Jing Hong Xia , Cui Li Li , Ye Yun , Wang Ya Kun
Published: March 2009

Nanometer level α-Fe2O3 is a sort of important nanometer material, which can be used
comprehensive in the field of catalysis, ultraviolet radiation absorption material, functional
ceramics and so on. This article uses the method of microwave radiation combined with high
temperature sintering to prepare dispersive and symmetrical α-Fe2O3 nanometer grains for the first
time, and this method not only may reduce the reactive cycle, but also may enhance the
concentration of reactive initial solution of FeCl3. At the same time, in the process of experiment we
found that if we put different crystal promotion agents in reaction solution at different calcining heat
and calcining time, we can obtain round, cubic or rod-like α-Fe2O3 nanometer grains separately.
Forming of Large Thin Walled Fused Silica Shapes by Gelcasting
Authors: Wang Shu Hai , Cui Wen Liang , Yang Xian Feng , Yuan Xiang Dong
Published: March 2009

Gelcasting was used to form large and thin walled shapes of fused silica. Large square crucibles
of 720x720x420 with a thickness of 14mm for polycrystalline silicon melting and fused silica radoms of
up to 500mm in diameter and 1000mm in height with a thickness of 10 to 12 mm have been formed and
sintered with excellent homogeneity. Process parameters have been discussed such as dispersion of the
ceramic particles in the casting slurry and design of the casting moulds. Simultaneous vibration treatment
was applied during the casting process for more homogeneous structure of the formed bodies for some of
the casting shapes.
Injection Molding of Zirconia Ceramics Using Water-Soluble Binder
Authors: Gao Yan , Huang Kang Ming , Fan Zhen Kun , Xie Zhi Peng
Published: March 2009

Water-soluble binder based injection molding of submicrometer-sized and stabilized zirconia
was reported in this paper. The binder phase is chosen as the mixtures of polyethylene glycol,
high-density polyethylene, polyvinyl butyral and stearic acid. Binder removal is accomplished by a
two-steped process. The water-soluble constituent is firstly removed by dissolution in the water and the
remaining is removed through the followed thermal treatment. The apparent viscosities of different kinds
of feedstock were tested. The influences of water-leaching time and temperature on the efficiency of PEG
removal were discussed.
Low Temperature Fabrication and Characterization of Porous SiC Ceramics Using Polycarbosilane as Binder
Authors: Ma Qing Song , Yu Xiao Dong
Published: March 2009

Polycarbosilane (PCS) and SiC powders, in which PCS acted as binder, were adopted as
starting materials to fabricate porous SiC ceramics. During pyrolysis, PCS experienced an organicinorganic
transformation and bonded SiC powders at a low temperature of 1273K. The flexural strength
of porous SiC ceramics increased with increasing PCS content and shaping pressure, while the porosity
decreased with increasing the PCS content, shaping pressure and particle size of SiC powders. The
fracture surface of porous SiC ceramics was observed.
Ultra-High Temperature Ceramics (UHTCs) via Reactive Sintering
Authors: Zhang Guo Jun , Wu Wen Wen , Kan Yan Mei , Wang Pei Ling
Published: March 2009

Current high temperature ceramics, such as ZrO2, Si3N4 and SiC, cannot be used at temperatures over 1600°C due to their low melting temperature or dissociation temperature. For ultrahigh temperature applications over 1800°C, materials with high melting points, high phase composition stability, high thermal conductivity, good thermal shock and oxidation resistance are needed. The transition metal diborides, mainly include ZrB2 and HfB2, have melting temperatures of above 3000°C, and can basically meet the above demands. However, the oxidation resistance of diboride monolithic ceramics at ultra-high temperatures need to be improved for the applications in thermal protection systems for future aerospace vehicles and jet engines. On the other hand, processing science for making high performance UHTCs is another hot topic in the UHTC field. Densification of UHTCs at mild temperatures through reactive sintering is an attracting way due to the chemically stable phase composition and microstructure as well as clean grain boundaries in the obtained materials. Moreover, the stability studies of the materials in phase composition and microstructures at ultra high application temperatures is also critical for materials manufactured at relatively low temperature. Furthermore, the oxidation resistance in simulated reentry environments instead of in static or flowing air of ambient pressure should be evaluated. Here we will report the concept, advantages and some recent progress on the reactive sintering of diboride–based composites at mild temperatures.
The Influence of Sintering Process on the Microstructure of Submicron Alumina Fabricated by Gelcasting
Authors: Qi Long Hao , Shen Jian , Pan Wei
Published: March 2009

Using ultra-fine alumina powders as raw materials, the submicron transparent alumina with relative density more than 99.9% was fabricated by gelcasting and then sintering-HIP process. It was found that only the samples with relative density more than 95% after presintering could obtain fully densification by post-HIP treatment. The final grain sizes increased after post-HIP treatment and were decided by either HIPing temperature or presintering temperature, depending on which one is higher. The maximal strength can reach about 650MPa when grain size is about 1 μm.
Effect of HIP on the Properties and Microstructure of Transparent Polycrystalline Spinel
Authors: Lei Mu Yun , Huang Cun Xin , Sun Jia Lin
Published: March 2009

In this paper, transparent polycrystalline magnesium aluminate spinel was fabricated by hot pressing ultra fine high purity spinel powder using LiF as the sintering aid in vacuum, then hot isostatic pressing (HIPing) the sintered body to improve the optical properties of the sample. The transmittance and the strength of the samples before and after HIPing were measured; morphologies of the fracture surface of the samples before and after HIPing were observed. Following hot pressing, the grain size of the sample is small; the transmission values are low and may varied at different sites in the same sample. After HIPing, the strength of the sample decreased, the grain size increased obviously, and the transmittance and the uniformity of transmittance increased significantly. The panel of transparent spinel up to 200 mm in diameter and 8 mm thick was fabricated by this method; the average transmittance of the spinel is above 80% in the range between 2 μm and 5 μm .
Mechanical Properties of C/SiC Composites via Precursor Pyrolysis with Pretreated Carbon Fiber
Authors: Wang Song , Chen Zhao Hui , Li Fan , Hu Hai Feng
Published: March 2009

3D C/SiC composites were fabricated by polycarbosilane (PCS) infiltration and pyrolysis
process. The influence of pretreatment of carbon fiber, including pyrolytic carbon coating and thermal
treatment, on mechanical properties of C/SiC composites was investigated. The results showed that the
composites without fiber pretreatment had a flexural strength of 154MPa and a fracture toughness of 4.8
MPa•m1/2, while those with carbon coating or thermal treatment had much higher strength and toughness,
that is, more than 400MPa and 15MPa•m1/2 respectively. Weak interfacial bonding and better in-situ
strength of carbon fiber were main reasons for mechanical property improvement with pretreated carbon
fiber.
Silicon Carbide Whiskers Synthesized by Double-Heating Technique
Authors: Zhao Ru , Dai Chang Hong , Cui Yi , Song Zu Wei
Published: March 2009

A new technique of mass-producing silicon carbide whiskers at a low cost is introduced in this
paper. Silicon carbide whiskers are synthesized by double-heating technique with the activated carbon
and silica gel as raw material and CoCl2 as catalyst. The results indicate that the silicon carbide whiskers
with the average diameter of 0.2μm, length of 10-50μm and high content of 81% can be obtained at a
lower temperature of 1300°C and a shorter time of 1.5h. Compared with the conventional heating, the
double-heating technique is suitable for realizing the scaled production because of the lower whiskerssynthesizing
temperature, shorter reaction time and greater output.
An Investigation of the Reaction Hot-Pressing Synthesis of MoSi2/Ti3SiC2/Al Composites
Authors: Zhang Jin Yong , Fu Zheng Yi , Wang Wei Min
Published: March 2009

MoSi2 is one of the few intermetallics to have potential for further systems. However, the use of
MoSi2 has been hindered due to the brittle nature of the material at low temperatures, inadequate creep
resistance at high temperatures, accelerated (pest) oxidation at temperatures between 450~ 550°C. In this
investigation Mo(Al,Si2)/Ti3SiC2 composites has been prepared by reaction hot-pressing from Mo, Si,
SiC, Ti, Al powder mixture under different temperatures. XRD results show that the main products are
Mo(Si,Al)2 and Ti3SiC2. Part of TiC and SiC also appeared at low treating temperature. With the treating
temperature increasing SiC disappeared. No evidence show lattice change of Mo(Si,Al)2. It must be the
results of sufficient Al added. The electrical conductivity properties were also investigated. Samples
treating under different temperatures showed different changes. Samples under high treating temperature
showed a near linear change ranging from 27~800°C and Samples under low treating temperature showed
a nonlinear change.
Spark Plasma Sintered ZrO2(Y2O3)-Al2O3-SrSO4 Self-Lubricating Nanocomposites for High Temperature Tribological Applications
Authors: Ouyang Jia Hu , Murakami Takashi , Sasaki Shinya , Zhou Yu , Jia De Chang , Wang Ya Ming
Published: March 2009

Spark plasma sintering is employed to synthesize a variety of self-lubricating ZrO2(Y2O3)-
Al2O3 matrix nanocomposites by tailoring the chemical compositions and by adjusting the sintering
parameters. Different additives are incorporated into the nanocrystalline ceramics of ZrO2(Y2O3)-
20wt.% Al2O3 to evaluate their potentials as effective high temperature solid lubricants from room
temperature to 800oC by using a high temperature friction and wear tester in sliding against alumina ball
in air. The density, microstructure, hardness and tribological properties of the sintered nanocomposites
have been investigated, as contrasted with the unmodified ceramics, to obtain a better understanding of
lubrication mechanisms over a wide temperature range. The ZrO2(Y2O3)-Al2O3-SrSO4 composite
exhibits steady-state friction coefficients of less than 0.2 and wear rates in the order of 10-6 mm3/Nm over
a broad temperature range from room temperature to 800oC.
A New Ti3AlC2/Cu Cermet Exhibiting Excellent Tribological Properties
Authors: Huang Zhen Ying , Zhai Hong Xiang , Ai Ming Xing
Published: March 2009

The tribological behavior of a new cermet Ti3AlC2/Cu was experimentally investigated. The
results showed that the Ti3AlC2/Cu was a good tribological material sliding against the low carbon steel,
especially for a high sliding speed. The friction coefficient was as low as 0.13 ~ 0.15, and the Ti3AlC2/Cu
wear rate was only 3.4×10-6 mm3/Nm, for the sliding speed of 60 m/s and the normal pressure of 0.8 MPa.
The forming of a frictional film consisted of Ti, Al, Cu and Fe oxides on the friction surfaces could be a
fundamental cause.
Fabrication and Characterization of Mullite Whisker-Reinforced Porous Refractory
Authors: Zhang Mei Jie , Wang Hou Zhi , Gu Hua Zhi , Huang Ao
Published: March 2009

The Al2O3-mullite system porous refractories were fabricated, and then pretreated by sol-gel.
The samples were sintered at 1200°C for 3 hours. The microstructures and phases of the samples were
analyzed by SEM and XRD respectively. The physical properties of the samples were measured
according to National Standard of Refractory. Mullite-whiskers were formed in the pores of the samples.
The pretreated samples were more permeable, and were greatly strengthened.
Mechanical Properties of Machinable Zirconia Dental Composites
Authors: Li Wen Xu , Zhao Hua , Song Ying , Su Bin , Wang Fu Ping
Published: March 2009

Ca3(PO4)2/ZrO2 dental composite ceramics using for CAD/CAM system were prepared and the effects of weak phases on microstructures and mechanical properties were studied. The results showed that intergranular spreads happened with the increasing Ca3(PO4)2 contents due to the discontinuity of weak interfaces between Zirconia and Calcium phosphate in matrix. So the flexural strength and hardness of the Ca3(PO4)2/ZrO2 composite ceramics were decreased effectively, which improved the machinability of the composites. On the other hand, strong interfaces between Zirconias increased the integrality of the ceramic structures. ZrO2 composite Ceramics with 15% Ca3(PO4)2 were sintered at 1350°C. The flexural strength is 300.44MPa, fracture toughness is 4.36 MPam1/2, and hardness is 6.69 GPa. The cutting exponent of the Ca3(PO4)2/ZrO2 composite ceramics is obviously lower than that of the common commercial Vita Mark II and Dicor MGC ceramics, which shows good mechanical properties and machinability.
Improvement of Anti-Washout Performance of Calcium Phosphate Cement Using Modified Starch
Authors: Chen Ling , Xiang Hong , Li Xiao Xi , Ye Jian Dong , Wang Xiu Peng , Li Lin
Published: March 2009

Calcium phosphate cements (CPCs) are well-known orthopedic materials for filling bone.
However, CPC pastes tend to disintegrate immediately when contacting with blood or other aqueous
(body) fluids, which is a main limitation of its clinical applications in bone repairing, reconstruction and
augmentation. To improve the anti-washout performance of CPC, modified starches such as
pre-gelatinized starch, etherified starch, and esterified starch were added to the liquid phase of CPC in this
work. CPC with good anti-washout performance was prepared and the effects of the modified starches on
the properties of CPC were investigated. The results showed that the CPC with the modified starches were
more stable in simulated body fluid than that without modified starch, especially the CPC with the
etherified starch (II). X-ray diffraction analysis revealed that the modified starches did not inhibit CPC
components from converting to hydroxyapatite. Furthermore, the anti-washout mechanism of the
modified starches in CPC was discussed. It is concluded that the addition of the modified starches such as
pre-gelatinized starch, etherified starch, and esterified starch to CPC can improve its anti-washout
performance and should be of value in clinical surgery where the cement is exposed to blood.
Preparation of Biphasic Calcium Phosphate Porous Ceramics Prepared from Fine Powders with Different Particle Size and its Dissolution Behavior in Simulated Body Fluid
Authors: Zhang Yin , Yokogawa Yoshiyuki , Kameyama Tetsuya
Published: March 2009

Biphasic calcium phosphate (BCP) ceramics, a mixture of hydroxyapatite (HAp) and betatricalcium phosphate (β-TCP), of varying HAp/β-TCP ratios was prepared. One kinds of HAp and one kind of β-TCP powders were used to produce porous BCP bioceramics with HAp/β-TCP weight rations of 20/80, 40/60, and 80/20. A slip was obtained by adding a mixed powders of HAp and β-TCP to a solution 1.5% of deflocculant and 0.5 wt% of foaming agent. The optimum value for the minimum viscosity in these present slips with respect to its solid loading and the optimum amount of the deflocculant were investigated. The specimen obtained by casting a polyurethane foam with 1.5 wt% of deflocculant into a slip, and drying it under vacuum, was heated at 1150°C for 3 hours. The resultant porous BCP sintered body had large spherical pores of 300 /m with interconnecting rectangular voids. Many small pores in the size range of 2-3 /m or below were observed in the specimen obtained by heating at 1150°C for 3 hours. The dissolution test was done as follows. The obtained porous ceramics samples about 0.5g individually soaked into 30 mL of simulated body fluid (SBF) solution at 36.5°C. The calcium and phosphorous content of the SBF solution was analyzed by ICP. The porous body was dried, and characterized using SEM, XRD, and FT-IR.
A Comparative Study of Two-Layer NiAl Bond Coat TBC and its Failure Mechanism
Authors: Li He Fei , Zhou Zhao Hui , A Hesnawi , Jiang Kuo , Gong Sheng Kai
Published: March 2009

Thermal barrier coatings with one-layered/ two-layered NiAl bond coat were produced by electron beam physical vapor deposition (EB-PVD). Compared to the TBC with one-layered bond coat, the TBC with two-layered bond coat improved the thermal cycling resistance significantly. The failure mechanism of the two-layer NiAl bond coat TBC was investigated in this paper.
Mechanisms and Kinetics of Silica-Rich Binary Na2O-SiO2 Glass Corrosion in 100°C Water at pH=7
Authors: Nickel K.G. , Merkel S.
Published: March 2009

Sodium-rich glasses of the system Na2O-SiO2 are well known to be easily soluble in water.
This is not true for silica-rich compositions. We have manufactured quenched glasses with silica contents
between 65 and 80 wt.% SiO2 and followed the water interaction at 100°C by measuring mass and sample
dimensions in intervals. Comparing the path of edge length, mass and volume to a general shrinking core
model for cuboids we conclude that only compositions between 65 and 70 wt% SiO2 can be described
well by a simple dissolution process. The logarithm of the dissolution rate constant varies linearly with
the SiO2 content. At higher silica contents the mechanism changes towards leaching of sodium. We
propose changing glass structures to be responsible for the change in mechanism.
Hierarchically Nanostructured Porous Functional Ceramics
Authors: Vantomme A. , Léonard A. , Yuan Zhong Yong , Su Bao Lian
Published: March 2009

We demonstrate here a self-formation phenomenon of hierarchy with multiple-scaled porosity. Macrochanneled structures, labelled as CMI-7, with openings ranging from 0.5 to 5.0 microns and wormhole-like mesoporous walls with various ceramic compositions, such as ZrO2, TiO2, Al2O3, Y2O3, ZrO2-SiO2, ZrO2-TiO2, ZrO2-Y2O3,…, aluminosilicates, aluminophosphates, silicoaluminophosphates, metallophosphates, can be prepared by just controlling the hydrolysis and polycondensation rates of the pre-selected ceramic sources. The macrochannels (funnel-like or straight) are well parallel each other and perpendicular to the tangent of the particles’ surface. These hierarchical porous ceramics can be used in catalysis, separation and for immobilization of biological molecules and even microorganisms for filtration and bioreactor applications.
Growth of TiO2 Thin Film on Glass Substrate by Air-Opened MOCVD
Authors: Li Li Na , Gu Jing Hua , Zhang Yue
Published: March 2009

MOCVD was applied to deposit TiO2 thin films on glass substrates. Effects of the deposition conditions (source temperature and substrate temperature) were studied. The phase and micro- structure of the TiO2 thin films were examined by X-ray diffraction and electron microscopy, respectively. The results indicate that substrate temperature affects both the morphology and the phase of the TiO2 film, while source temperature only affects the surface morphology of TiO2 film. Highly oriented anatase film on glass substrate was obtained at a source temperature of 140 oC and a substrate temperature of 350 oC. XRD pattern shows that only the (200) peak of anatase appears under the conditions. The crystallines in the highly oriented anatase were rectangular in top view.
Preparation of Nanosize Anatase TiO2 Powders by Hydrothermal Synthesis
Authors: Ran Fan Yong , Cao Wen Bin , Li Yan Hong , Zhang Xiao Ning
Published: March 2009

Nanosize anatase TiO2 powders have been synthesized by hydrothermal synthesis by using technical grade TiOSO4 as precursor and urea as precipitating agent. The initial pressure of the reaction system was set at 6 MPa. Stirring speed was fixed at 300r/min. The reaction system reacted at the temperature ranged from 110 to 150°C for holding 2hrs to 8hrs and the concentration of the precursor was ranged from 0.25M to1.5M. XRD patterns show that the synthesized powders are in the form of anatase phase. Calculated grain size is ranged from 6.7 to 8.9nm by Scherrer method from the line broadening of the (101) diffraction peak of anatase. The specific surface area of the powders synthesized under different conditions is ranged from 124 to 240m2/g. The grain size of the powders increases with the increase of the reaction temperature, holding time and precursor concentration, respectively. The specific surface area decreases with the increase of reaction temperature and holding time, and does not obviously change with the change of precursor concentration when the concentration of the precursor is less than 1M. However, when the concentration is higher than 1M, the specific surface area will decrease quickly with the increase of the precursor concentration. XRD and DSC-TG analysis shows that the synthesized anatase TiO2 will begin to transform to rutile TiO2 at about 840°C. When heated to 1000°C for holding 1h, the anatase powders will transform to rutile completely.
Synthesis of VO2 Nanocrystalline via Hydrothermal Method
Authors: Luo Min , Gao Ji Qiang , Zhang Xiao , Ouyang Da , Yang Jian Feng , Zhu Jian Feng
Published: March 2009

Vanadium dioxide nanocrystalline of various morphology have been synthesized from V2O5 sol and organic molecules as the structure-directing templates under hydrothermal conditions. XRD, TEM and SEM are applied to study the characteristics of samples. Cetyltrimethylammonium bromide (CTAB) and sodium dodecylbenzenesulfonate (SDBS) are demonstrated to be appropriate templates for the formation of vanadium dioxide nanocrystalline. The probable formation mechanisms of the vanadium dioxide are also discussed.
Preparation and Characterization of CdSe Synthesized from Non-Aqueous Media
Authors: Kim Shin Ho , Lee Yoon Bok , Cho Seung Chan , Rhyim Young Mok , Kim Jin Chun , Kim Young Seok , Kim In Bae , Kim Yang Do
Published: March 2009

Cadmium selenide (CdSe) have been prepared by the reduction of mixed solution of cadmium
chloride (CdCl2), sodium selenosulfate (Na2SeSO3) and diethanolamine ((CH2CH2OH)2NH) at temperatures
of 80-200°C under Ar atmosphere. Characteristics of CdSe nanoparticles were analyzed using
transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction
(XRD) and UV-Vis absorption spectra. CdSe samples prepared at relatively low temperature of below
100°C showed cubic structure while samples synthesized at temperature above 100°C showed hexagonal
phase. The increased reaction temperature caused the particle size increase as well as the agglomeration
of particles to form a hollow sphere. UV-Vis absorption spectra also showed a red-shift as increasing
reaction temperatures due to the gradual growth of CdSe nanoparticles in the solution. The relatively
sharp absorption band from samples synthesized at 80 and 100°C can be attributed to homogeneous
particle size distribution compared with those of prepared at elevated temperatures. This paper will
mainly discuss the phase stability of CdSe nanoparticles as well as the hollow sphere formation.
Microstructure and Mechanical Properties of SiC-Al2O3 Nanocomposite Prepared by Surface Modified SiC Nanopowders
Authors: Yan Lu Ting , Si Wen Jie , Liu Lian Yun , Zheng Yan Peng , Dai Chun Ai
Published: March 2009

SiC nanopowders were surface modified by low temperature plasma polymerization. 5vol%
SiC-Al2O3 nanocomposite was prepared by adding the surface modified SiC nanopowders into the matrix
of Al2O3.The influence of surface modified SiC nanopowders on the properties and structure of SiCAl2O3
nanocomposite was studied. The surface modified SiC-Al2O3 nanocomposite had higher density
and nicer mechanical properties than untreated SiC- Al2O3 nanocomposite because of the improvement of
dispersion. The hardness and toughness of the SiC- Al2O3 nanocomposite were higher than monolithic
Al2O3 but the ultimate bending strength was not perfect because of retardation of the densification and
formation of unsintered pores caused by the induced oxygen during the process of powder treatment.
Effect of the Addition of Ti3+ into TiO2 Film on the Performance of Dye Sensitized Solar Cells
Authors: Xiang Jun Hui , Zhang Zhi , Zhang Fu Shi , Kaneko Shoji , Okuya Masayuki , Zhang Hui Ping
Published: March 2009

For the first time, it was found that low-valence additives could be employed to improve the
conversion efficiency of dye sensitized solar cell. It was experimentally discovered that by forming
nonstoichiometric compound, Ti3+ was located in the lattice of TiO2 film, generating surplus electrons
within the film and affecting the morphology of TiO2 particle. The improvement of the conversion
efficiency of the solar cell was mainly due to the increase of short circuit current along with the content of
Ti3+. The surface of the TiO2 particle became more coarsely after TiCl3 added and the absorbed dye
molecules was increased. It was another reason of the improvement of conversion efficiency.
Properties of Ultrafine High Curie Temperature (1-x)BiScO3-xPbTiO3 Ferroelectric Ceramics
Authors: Zhao Wei , Wang Xiao Hui , Gui Zhi Lun , Li Long Tu
Published: March 2009

Ultrafine (1-x)BiScO3-xPbTiO3 ferroelectric ceramics were successfully prepared by employing nanocrystalline ceramic powder. The average ceramic grain sizes range from 0.4μm to 1.2μm with different phases and different proceeds. The studies show the average grain sizes vary with the calcining and sintering temperature as well as the compositions in different phases. Ceramics, sintered at 1020°C for 3h, in morphotropic phase boundary (MPB) have the smallest grain sizes around 0.4 μm, those in tetragonal phase and rhombohedral phase have larger grains around 0.9μm. Meanwhile, the piezoelectric property and Curie temperature were founded size-dependent when the grain sizes are smaller than 1μm.
Preparation and Investigation of TiO2 Sol Containing Nanometer Anatase Crystalline Grains
Authors: Gao Ji Wei , Shen Qian Hong , Fang Ming , Wang Ping , Li Li
Published: March 2009

TiO2 sol containing nano anatase crystalline grains was prepared using Ti(OC4H9)4 as a
precursor in a water-excessive reaction system. The processes of hydrolytic-polymeric reactions and the
structures of the products were analyzed. It was found that the -OC4H9 radicals previously linked to Ti
atom in Ti (OC4H9) 4 molecular are broken, and there is no organic radicals linked to Ti atoms in the final
sol. The structure of particles in the sol changes along with time from tetrahedral [TiO4] to octahedral
[TiO6], with the coordination number changing from 3.14 to 5.18, accordingly. Therefore, the structure
becomes closer to an anatase, which is octahedral [TiO6] with a coordination number of 6.0. Transmission
electron microscope micrograph also reveals the foursquare projection shape of crystalline grains with a
size of 200 nm in the sol. As the particles in the sol have a quasi anatase structure, the TiO2 sol can directly
photodegrade Rhodamine B under Ultraviolet illumination with a rate of 62.35%.
Kinetics Model for the Initial Stage of Spark Plasma Sintering
Authors: Fang Ming Hao , Pan Wei , Shi Sui Lin , Fang Zhen Yi
Published: March 2009

The sintering kinetics model of initial stage by spark plasma sintering (SPS) is discussed in this paper. During SPS, there are discharges among the powder particles. And the particles surface will be melted and form viscose flow. These phenomena accelerate the particles rearrangement and reduce the sintering time. The relationship between the shrinkage ratio of particles and the sintering time during the initial stages of sintering by SPS has been obtained. The results show that L/L0 is linear to the time.
Assessment of the Surface Morphology of Diamond Film Based on Fractal
Authors: Lin Jiang Li , Ran Jun Guo , Wang Tian Fu , Gou Li , Hua Ya Hui , Liao Xiao Ming
Published: March 2009

The surface morphology of film material directly affects its physical performance. It is of great
significance for finding out its prospective physical performance to characterize the surface morphology
of film material. It is hard to characterize them with some conventional methods. The surface morphology
of film material was described from the fractal point of view, and the dimension was correlated with the
resistivity of material. The [100]-orientated diamond film was primarily investigated. The results show
that the greater the crystal grain is, the more uniform and regular the orientation is; and the more compact
the arrangement is, the greater the fractal box dimension is. Moreover, when fractal box dimensions were
within a certain range approximately from 2.92 to 2.97, it presents positively correlative relation with the
logarithm of resistivity, Log(ρ), which resembles the Logistic curve. However, when the other dimensions
are beyond the range mentioned above, resistivity doesn’t change with the increase in dimensions of
fractal. This study will conduce to illustrating the relationship between the structure of crystal exemplified
by arrangement and physical performance as well as material preparation.
Functionally Graded Thermoelectric Materials
Authors: Ge Chang Chun , Wu Xiao Feng , Xu Gui Ying
Published: March 2009

Functionally graded thermoelectric material (TE FGM) is one of main research direction in research field of thermoelectric (TE) materials all over world. A lot of research work on TE FGM has been done to improve the conversion efficiency of TE. Here the development of TE FGM in recent years is discussed in the aspects of the model design, the materials selection, the barrier or joining choice and the device fabrication.
Preparation of Functionally Graded Cu/AlN/Cu Electrode Materials for Thermoelectric Devices
Authors: Zhang Huai Quan , Li Jing Feng
Published: March 2009

The Cu/AlN/Cu functionally graded materials (FGMs) were successfully fabricated using the
spark plasma sintering (SPS) method, and a two-step process was used. First, a symmetrical porositygraded
AlN plate was prepared using AlN powder consisting of particles of varying sizes. Afterwards,
graded Cu/AlN/Cu samples were made by introducing Cu into the pores of the external, porous AlN layer.
Numerical Simulation Method of Heat-Resistant Hetergeneous Graded Ceramics Structure on Vehicle
Authors: Li Yong
Published: March 2009

From macroscopic view, major structure characteristic of ceramics-metals FGM lies in the fact that every Graded layer is composed of ceramics and metals of different volume component ratio, with their component, structure form or substance parameter presenting Graded change. During temperature rising and dropping, thermal stress will be produced between macroscopic Graded layers and thermal substance mismatch of meso-scopic reinforce phase and matrix within every Graded layer will produce monolayer thermal stress, leading to the failure of overall materials. Because FGM differs obviously in organization states along Graded direction from perpendicular direction, Graded structure shows the distribution features of macroscopic nonhomogeneities, anisotropy and meso-scopic mechanical continuity. Recent related studies mainly adopt FGM equivalent method, particle interface crack theory, uniform theory and effective performance forecasting.
Effects of CuO and V2O5 Addition on Sintering Behavior and Microwave Dielectric Properties of (1-x)Ca2P2O7-xTiO2
Authors: Cho In Sun , Kang Sang Gu , Kim Dong Wan , Hong Kug Sun
Published: March 2009

The effects of CuO and V2O5 addition on sintering behaviors and microwave dielectric
properties of 0.7Ca2P2O7-0.3TiO2 ceramics were investigated. With CuO and V2O5 addition, the sintering
temperature of 0.7Ca2P2O7-0.3TiO2 can be effectively reduced from 1150 to 950oC. The dielectric
constant of the low fired 0.7Ca2P2O7-0.3TiO2 ceramics was not significantly changed while the quality
factor was affected by additives. The temperature coefficient of resonant frequency value was increased
in negative value with the additive contents. V2O5 and CuO additives effectively improved the
densification and dielectric properties of 0.7Ca2P2O7-0.3TiO2 ceramics. The correlation between the
phase constituents and the dielectric properties was investigated with additive contents.
Preparation and Properties of Ce0.9Sm0.1O1.95 as the Electrolytes of IT-SOFC
Authors: Xu Li Hai , Xu Yu Xing , Wang Cong , Wang Tian Min
Published: March 2009

Sm0.1Ce0.9O1.95 (SDC) films, as promising electrolyte materials, have been successfully prepared on Al2O3 ceramic substrates by RF magnetron sputtering growth. The relationship between sputtering parameters and film microstructure was discussed. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to characterize the morphology and crystal structure of the SDC films. The SEM images show that the crystallinity becomes better and better with the increase of sputtering power from 100W to 300W. X-ray diffraction patterns indicate that the thin SDC electrolyte film on the Al2O3 ceramic substrate grows preferentially along the (111) compact plane with a pure fluorite structure when the RF power reaches 300W. After annealing treatment at 600°C and 800°C, respectively, it can be seen that SDC film becomes denser with few pinholes at the annealing temperature of 800°C. High oxygen ion conductivity (1.46×10-2 Scm-1) of the SDC film was obtained when the RF sputtering power and annealing temperature were 300W and 800°C, respectively.
Nitrate-Citrate Combustion Synthesis and Properties of Ce1-xGdxO2-x/2 Solid Solutions
Authors: Peng Cheng , Zhang Zhen
Published: March 2009

The structure, thermal expansion coefficients, and electric conductivity of Ce1-xGdxO2-x/2 (x = 0
~ 0.6) solid solutions, prepared by gel-combustion method, were investigated. The uniform small particle
size of the gel-combustion prepared materials allows sintering of the samples into highly dense ceramic
pellets at 1300°C, a significantly lower temperature, compared to that of 1600~1650°C required for ceria
solid electrolytes prepared by traditional solid state techniques. XRD showed that single-phase solid
solutions have been formed in all investigated range. The maximum conductivity, σ600°C = 5.26×10-3S/cm,
was found at x = 0.2. The thermal expansion coefficient, determined from high-temperature X-ray data is
8.125×10-6 K-1 at x = 0.2.
Electrochemical Performance of AA Size MCMB/LiCoO2 Lithium-Ion Battery Using Three-Electrode Cell
Authors: Lian Fang , Yu Zhong Bao , Zhong Sheng Wen , Xu Li Hua , Liu Qing Guo
Published: March 2009

AA size Li-ion batteries using LiCoO2, MCMB and lithium metal as cathode, anode and
reference electrode respectively were assembled, in order to study the individual effect of anode and
cathode on the cyclic and overcharge performances. The experimental results showed that the LiCoO2
cathode was the main electrode related to the capacity decay and discharge voltage drop. Increasing
polarization of the LiCoO2 cathode, especially at overcharge situation, and the irreversible change of
cathode structure led to reduction of discharge capacity and voltage plateau of batteries.
Al2O3 Coating of Spherical LiNi0.8Co0.2O2 for Li-Ion Batteries
Authors: He Xiang Ming , Pu Wei Hua , Zhao Fang Hui , Ying Jie Rong , Jiang Chang Yin , Wan Chun Rong , Zhang Shi Chao
Published: March 2009

Spherical LiNi0.8Co0.2O2 powders with particle size of 8~10μm were prepared based on
controlled crystallization, and coated with Al2O3 by Al(OH)3 sol, that was prepared from Al(NO3)3 and
NaOH, at first time. SEM, XRD and surface element analysis showed that the nano-sized Al2O3 was
coated uniformly on the surface of LiNi0.8Co0.2O2 powder. At 25 °C, the initial discharge capacity
decreased from 160 to 149 mAh g-1 after coating of Al2O3. The initial discharge capacity decreased from
168 to 163 mAh g-1 after coating of Al2O at 55 °C. After coating of Al2O3, the capacity retentions
increased from 83.8% to 92.6% at the 50th cycle at 25°C, and from 36.3% to 90.8% at the 10th cycle at
55°C. This paves effective way to improve the performance of LiNi0.8Co0.2O2 material for rechargeable
lithium ion batteries.
Novel-SiO2-Doped Proton Exchange Membrane for Self-Humidifying Fuel Cell
Authors: Wang Cheng , Wan Nian Fang , Mao Zong Qiang , Xu Jing Ming
Published: March 2009

To retain the optimum hydration level of the proton exchange membrane fuel cell (PEMFC)
without humidification sub-system, a novel self-humidifying composite membrane was fabricated by
the technology of Si[OCH2CH3]4 in situ sol-gel reaction in a commercial Nafion 112 membrane. The
physico-chemical properties of the membrane were studied by means of AFM, SEM and AC
impedance. These results showed that the nano-SiO2 reactant was uniformly distributed in the
composite membrane. It was found that the proton conductivity increased observably by dispersing 3
wt % nano-SiO2 in the composite membrane at low water content, and the SiO2/Nafion composite
membrane improved the self-humidifying performance of PEMFC.