bluuebunny/crossref_metadata_2025 huggingface dataset:
Insights to Extrusion from Finite Element Modeling
Authors: McQueen H.J. , Evangelista E.
Published: March 2009

The modeling of extrusion of various Al alloys and their particulate metal matrix composites was conducted by DEFORM™ finite element analysis to develop strain rate, stress and temperature distributions through the peak load and into steady state following development of the hot zone. The hot strength and ductility, constitutive constants and microstructural evolution had been determined by hot torsion. The relative load-stroke curves were determined for several billet temperatures, extrusion ratios and ram speeds. The grid distortion and distributions of important internal parameters define the evolution of microstructure. The extrudability was estimated on the basis of load, ductility and the potential for modeling the microstructure developed.
Preparation of Mg,Al-Hydrotalcite/PE-EVA Flame-Retardant Nanocomposite
Authors: Ren Qing Li , Luo Qiang
Published: March 2009

The Mg,Al-hydrotalcite/PE-EVA flame-retardant nanocomposites were prepared by the
co-mixing method at atmospheric pressure successfully. Moreover, the preparation of Mg,Alhydrotalcite/
PE-EVA nanocomposites was investigated according to the mechanical and flame-retardant
tests of the samples. And the results show that the Mg,Al-hydrotalcite nanocrystalline is a highperformance
inorganic flame-retardant agent.
Effects of Processing Parameters of SPS on the Densification and Texture of LaPO4 Ceramics
Authors: Du Ai Bing , Qu Zhi Xue , Wan Chun Lei , Han Ruo Bing , Pan Wei
Published: March 2009

Spark plasma sintering was used to fabricate the LaPO4 ceramics and the effect of SPS holding time and sintering temperature on the densification and texture of LaPO4 ceramics were studied. The results revealed that holding time had no obvious influence on the densification of LaPO4 ceramics under the present process. The density increases with the increase of sintering temperature, when it reached 1350°C, the relative density kept nearly constant of 98.6 %. The preferred orientation of LaPO4 ceramics approximately increases with the increase of sintering temperature, but contrary impact in holding time.
Effects of Microstructure on Cavity Nucleation in Creeping Ceramics Containing Viscous Grain Boundary Phase
Authors: Wang Chao , Liang Jun , Liu Yang , Han Jie Cai
Published: March 2009

A theoretical model considering the distribution of the grain sizes and grain-boundary ledges was developed for cavity nucleation in creeping ceramics containing viscous grain boundary phase. The critical stress involving the effects of various shapes of cavities and viscosity coefficient (η) for cavity nucleation was presented. Then, the local stress concentration factor concerning different distributions of grain-boundary ledges was calculated and discussed. The results showed that various shapes of cavities and η are not the main influencing factors on the critical stress. The stress concentration factor increases with the increase of grain-boundary ledge size or the density. Therefore, it would be liable to cause cavity nucleation at gain boundary when the density of grain-boundary ledges is high and the size is large.
Influence of Varying the Powder Loading Content on the Homogeneity and Properties of Extruded PZT-Fibers
Authors: Heiber Juliane , Clemens Frank J. , Graule Thomas , Hülsenberg Dagmar
Published: March 2009

In this study PZT-green fibres containing 50, 54 and 58 vol.% PZT powder were extruded. The influences on the mixing torque, the apparent shear rate and the extrudability were investigated and a theoretical maximum powder loading content was calculated using a model introduced by Frankel and Acrivos. The influence of powder loading content on the microstructure (porosity and grain size), the phase composition and on the final ferroelectric properties of sintered PZT fibres was investigated. The measurements revealed that the production of PZT fibres with homogeneous properties requires a minimum powder loading content of 58 vol.% PZT powder.
Numerical Simulation of Temperature Field and Thermal Shock Resistance Property of Permeable Brick
Authors: Gu Hua Zhi , Wang Hou Zhi , Zhang Mei Jie , Huang Ao , Zhang Wen Jie
Published: March 2009

The temperature distribution of the permeable brick was modeled using CFX software. The
influence of magnesia and corundum on thermal shock resistance of non-cement bonded alumina-based
permeable brick was investigated. The results indicated that, in the gas blow process, the high
temperature regions near the working face of the brick gradually expanded with the increase of the gas
flow rate. Therefore the inner part of the brick had the complex and large change of thermal stress. Further
experiments demonstrated that thermal shock resistance of alumina-magnesia based castable refractory
was better than that of alumina-chrome based castable refractory. With the increase of magnesia amount,
the alumina-magnesia based castable refractory had more cycles of heating and water-cooling. When
different kinds of corundum were added in the raw materials, the sample with tabular corundum showed
the best thermal shock resistance, the one with white fused corundum performed worse and the one with
fused dense corundum performed worst.
Preparation of Calcium-Deficient Carbonated Hydroxyapatite Nanoparticles by Microwave Process
Authors: Chen Song , Ji Jin Gou , Xu Yi , Liu Wei Qi , Chen Ji Da , Zhou Zhi Guo
Published: March 2009

In this paper, carbonated calcium-deficient hydroxyapatite (d-HA) nanoparticles were
synthesized by a chemical precipitation method assisted with microwave irradiation. The important
factors which effected on the synthesis process, such as pH value, time and the power of microwave
irradiation on the Ca/P molar ratios of d-HA were discussed. The experimental results showed that
carbonated d-HA nanoparticles could be quickly synthesized by irradiating the reaction solution for about
1h under moderate microwave power and pH value ranging from 8 to 9.
Dense Calcium Phosphate Bioceramics Sintered by Microwave Plasma
Authors: Ji Jin Gou , Xu Yi , Chen Song , Liu Wei Qi , Ran Jun Guo
Published: March 2009

Two kinds of dense calcium phosphate (Ca-P) bioceramics, hydroxyapatite (HA) and β-
tricalcium phoshpate/hydroxyapatite (β-TCP/HA), sintered by microwave plasma were investigated. The
dense HA and β-TCP/HA bioceramics exhibited higher density, smaller grain size and higher Vickers
hardness. The sintering behaviors of HA powder were also significantly different from those of calciumdeficient
hydroxyapatite (d-HA) powder by the same microwave plasma sintering route. The sintering
efficiency of the former was higher than that of the latter. The results indicate that dense HA and
β-TCP/HA bioceramics are of better mechanical strength and might have better bioactivity.
Bioactivity, Wear and Corrosion Resistant Properties of Rare Earth/Calcium Phosphate Composite Coatings
Authors: Ma Chen , Wang Ying Hui , Li Mu Qin , Qu Li Jie
Published: March 2009

Rare earth/calcium phosphate composite coatings were fabricated on the surface of Ti-6Al-4V
by micro-arc oxidation (MAO) technique. The wear properties and corrosion resistant of rare earth/
calcium phosphate composite coatings in the simulated body fluid (SBF) have been investigated and the
bioactivity of the composite coatings were evaluated. The results show that the friction coefficient of the
composite coatings in the SBF is only 0.15~0.18 and the anode polarization potential of the coating has
been obviously enhanced about 0.18V compared with that of coatings of calcium phosphate coatings. So
the composite coatings have excellent wear and corrosion resistant properties. XRD analysis indicates
that the composite coatings can induce hydroxyapatite to form on its surface after soaked in SBF for 9d,
which shows that the composite coatings own good bioactivity.
Preparation and Characterization of CaCu3Ti4O12 Ceramics by Cold Isostatic Press Forming
Authors: Li Jie , Xue Hao , Xiong Zhao Xian
Published: March 2009

CaCu3Ti4O12 (CCTO) ceramics were prepared by cold isostatic press (CIP) forming combined with the conventional sintering method. The effects of calcining temperature on properties of CCTO ceramics were investigated. The dielectric properties as the function of temperature at typical frequencies were measured in the temperature range from 243 to 363 K. In addition, the dielectric properties and complex impedances at room temperature were analyzed in a frequency range from 20 Hz to 106 Hz. The results showed that CCTO ceramics with dielectric constant higher than 104 were obtained. Compared with the dry press forming, CCTO ceramics prepared by CIP had more homogeneous grains, less porosity and better dielectric properties.
Mechanical Properties and Microstructure of Partially Sintered Zirconia Ceramics
Authors: Li Shi Bao , Chen Zhao Hui , Zhao Yi Min , Wang Zhong Yi , Tang Li Hui , Zhao Xin Yi , Chen Jin Wu , Xie Cheng , Li Xiao Na
Published: March 2009

Partially sintered zirconia ceramics (PSZCs) for dental uses were prepared from zirconia nanopowder
via isostatic pressing and partially sintering. The open porosities, pore diameters, grain sizes and
mechanical properties of the ceramics with different densities were studied. The results show that the
pores formed in the PSZCs are all open pores, with a diameter distribution of 60nm~130nm and a grain
size distribution of 120~170nm. The machinability becomes worse when the density of PSZC is higher
than 75% of the theoretical density, so a ceramic named PSZC-70% with density of 70%TD was selected
as the target material. Its bending strength is 168 MPa and fracture toughness is 1.8 MPa·m1/2. A dental
restoration framework can be obtained via machining the PSZC-70% on a dental CAD/CAM system.
Effect of SnO Coatings on the Bond Strength between Titanium and Porcelain
Authors: Liu Xiao Chen , Guo Li Tong , Gao Ji Qiang , Guo Tian Wen , Liu Li , Li Shi Bao , Li Xiao Na
Published: March 2009

The aim of this investigation is to study the effect of SnO coatings on the bond strength between titanium and porcelain. The coatings were produced by sol-gel method and heat-treatment at 300°C. Once the coatings have been formed on the titanium substrates, self-made porcelain was fused. The specimens with pre-oxidation before porcelain fused were set as control group. It was shown SnO gel formed completely at 300°C and was composed by SnO and SnO2 in the form of a uniform film. The bond strength between titanium and porcelain of the specimens with SnO coatings was greater than those in control group statistically, which might prove that the coatings reduced the oxidation of titanium surface in the porcelain fusing progress. EDS result showed almost all fractures between titanium and porcelain occurred at the oxide layer. Si and Sn might attend the reaction at interface. It was concluded that the SnO coatings produced in this study can improved the titanium-porcelain bond strength.
Rapid Reversible Superhydrophobicity to Superhydrophilicity Conversion of HF-Tuned ZnO Flower-Like Micro-Sphere Films
Authors: Liu Chang Song , Li Zhi Wen , Wang Ling , Xu Zhen
Published: March 2009

Superhydrophobic ZnO films were prepared by a simple low-temperature solution method,
where the ZnO morphology was tuned by hydrofluoric acid. The film topography presents two different
length scales: micro flower-like-spheres and nano petals. Such hierarchical structures give the film a
superhydrophobic behavior with water contact angle (CA) of 151°, turning into a superhydrophilic one
(CA < 5°) after 30 min vacuum ultraviolet (VUV) illumination. The transition from superhydrophobicity
to superhydrophilicity is more quickly than the past report using UV illumination because VUV gives
higher energy upon the ZnO films. The VUV-illuminated film can be recovered to superhydrophobic
through being placed in the dark. Such special wettability can be explained based on ZnO as a
photoinduced semiconductor and a photocatalyst. This study will greatly extend applications of ZnO
nanomaterials to many important fields, such as microfluidic devices.
Synthesis of Aluminium Titanate Ceramics from Waste Sludge of Aluminium Factory
Authors: Shen Yang , Ruan Yu Zhong , Yu Yan , Zheng Yun Hong
Published: March 2009

Aluminium titanate was synthesized using waste aluminium sludge and chemical pure TiO2
powder as raw materials. Effect of different compositions on crystal structure and contents of target
product was discussed. XRD results showed that four crystal phases, aluminium titanate, perovskite,
rutile and aluminum oxide, are formed in the sintered samples. The content of aluminium titanate
increases first and then decreases with the decrease of the content of waste aluminum sludge. When the
content of the sludge is 65.52wt%, the content of aluminium titanate reaches the maximum of 86.1wt%.
Mass Loss in SiC Crystal Growth Process
Authors: Cheng Ji Kuan , Gao Ji Qiang , Yang Jian Feng , Liu Jun Lin , Jiang Xian , Shi Yong Gui
Published: March 2009

The research investigated the mass loss in SiC crystal growth process by analyzing the effects
of the content of Si appending in sources material, growth temperature, growth time and atmosphere
pressure. The results indicate that mass loss of total system material (source material + crucible + crystal)
and crucible augments with increasing of content of Si in sources material, growth temperature and
growth time, but crystal mass gain increases. With increasing of atmosphere pressure, mass loss of system
material decreases, crucible mass loss increases, crystal mass gain decreases. Si inclusions in crystal
multiply with the increasing of the content of Si in source material.
Application of Master Sintering Curve Theory to Predict and Control the Sintering of Nanocrystalline TiO2 Ceramic
Authors: Li Da , Chen Shaou , Shao Wei Quan , Ge Xiao Hui , Zhang Yong Cheng , Zhang Sha Sha
Published: March 2009

Master sintering curve (MSC), in which the sintered density is a unique function of the integral
of a temperature function over time, is insensitive to the heating path. In this paper, the densification of
rutile TiO2 was continuously recorded at heating rates of 2 °C/min and 5 °C/min, respectively, by
dilatometer. The MSC for rutile TiO2 was constructed for pressureless sintering using constant heating
rate date based on the combined-stage sintering model. The construction and application of the MSC were
described in detail for different thermal histories. The MSC can be used to predict and control the
densification, final density, and microstructure evolution during the whole sintering. The final density can
be predicted for an arbitrary temperature–time path. A good consistence exists between the predicted and
experimental densification curve, confirming that it is possible to accurately predict and control the
sintering behavior of TiO2 from the initial to final stage of sintering using MSC.
Effect of Sn on the Sintering of Fe-Si Alloys
Authors: Li J.G. , Yuan W.J. , Zhou Y. , Zhang Lian Meng
Published: March 2009

In this work, Fe and Si powders were used to fabricate 6.5% Si silicon steel. The mixing
powder was rolled into strip and then treated at 900°C in Ar. Sn was added into the mixing powder to
investigate the effect of Sn on the sintering. The density, composition, and structure were examined. The
results show that Fe almost does not react with Si at 900°C. But with the addition of Sn, Fe reacts with Si
to produce Fe3Si at 900°C. Increasing the amount of Sn accelerates this reaction. When the amount of Sn
addition is excessive, there will leave many pores in the alloy because the reaction rate is too fast to
shrink. The proper amount of Sn addition can decrease the sintering temperature and shorten the sintering
time.
Microwave Joining of 95Al2O3 Using Interlayer Containing SiC
Authors: Wang Wei , Liu Jia Chen , Li Zhong Qiu , Fan Wei
Published: March 2009

A novel technique to join ceramics was described using microwave heating. SiC was added in
the interlayer as a microwave-absorbing material, joining of 95 Al2O3 was realized by raising temperature
of SiC itself and then inducing microwave-absorbing of oxides. The strength of joining, microstructure of
interlayer and mechanism of joining were investigated.
Effect of Heat Treatment on Specific Surface Area of Si-C-O Fibers
Authors: Chu Zeng Yong , He Rong An , Cheng Hai Feng , Li Xiao Dong , Wang Jun
Published: March 2009

In this paper, effect of heat treatment on the SSA of Si-C-O fibers was investigated and
morphologies of the treated fibers were studied using SEM. The results revealed that weight loss was
proportional to the treatment time at 1573K and the specific surface area (SSA) increased sharply when
the weight loss reached above 6wt%. A rough and porous ceramic fiber with SSA of 23.76m2/g could be
obtained at the weight loss of 9.1wt%, as a result of the treatment at 1573K for 32h.
Strength Model of Melt-Growth Composite Ceramics
Authors: Ni Xin Hua , Zheng Jian , Gao Ke Lin , Dai Hong Bin
Published: March 2009

The present work focuses on the failure mechanisms that occur in melt-growth composite
ceramics mainly composed of fiber eutectics with random orientation. First, the stress field of the
melt-growth composite ceramics under a tensile stress was obtained. It can be visualized that tensile force
is transmitted between oxide fiber eutectics by means of shear stress that develop along the interfaces of
oxide fiber eutectics. Consider fiber eutectics having lengths smaller than the critical length. During the
composite ceramics fracture, fiber eutectics do not fracture. The average stress of a fiber eutectic can be
determined by the shear stress. Then, the probability of ending fiber eutectics and bridging fiber eutectics
can be gotten by defining a critical ditrict βl. Finally, consider random orientation and length of the fiber
eutectics. Composite ceramics failure by slip incompatibility. The strength model of the melt-growth
composite ceramics is built. It is accordance with experiments.
Atomistic Simulation of Defect Energy in Pyrochlores and its Effect on Disorder
Authors: Zhang Hui Ling , Fan Qun Bo , Wang Fu Chi , Zhang Feng
Published: March 2009

To enhance the high-temperature stability of zirconate pyrochlore structures, one has to focus
on their transformation to the disordered state, fluorite. An atomistic simulation calculation is presented
in this paper to predict the propensity of rare earth zirconate pyrochlores to transform to fluorite at high
temperature. By detailed calculation of defect formation energy of cation antisites and Frenkel pair, as
well as their interactions, the mechanisms of disorder transformation are ascertained. The results show
that the tendency of cation disorder is less than the anion’s and disorder transformation will accelerate in
advanced stage. The calculation of defect energy in pyrozirconates with different cation on the A site have
proved helpful in unraveling their different order-disorder transformation tendency.
Study of Different TiO2 Electrode Structures on Dye-Sensitized Solar Cell
Authors: Meen Teen Hang , Huang Chien Jung , Chen Yin Wei , Ji Liang Wen , Diao Chien Chen , Chung Ho Hua
Published: March 2009

In this research, applications of different TiO2 electrode structures on Dye-Sensitized Solar Cell
were investigated. The different TiO2 electrode structures include: (1) synthesis of TiO2 nano-particles
and TiO2 film electrode by sol-gel and spin-coating method; (2) fabrication of the TiO2 film electrode by
RF Sputtering; (3) fabrication of the rod TiO2 electrode by photo lithography. X-ray diffraction patterns
show that the best sintering temperature of nano-TiO2 thin film is 500oC, at which TiO2 anatase phase
forms best and the smallest particle-size (8-10 nm) can be obtained. Ultraviolet-visible absorption spectra
reveal that the rod TiO2 electrode with TCPP sensitizer adsorbed on has the best optical absorption from
400 nm to 700 nm. The results of current-voltage analyses reveal that the solar cell with rod TiO2
electrode has higher conversion efficiency than the others. This result also provides clear evidence for the
contact area between TiO2 electrode and TCPP sensitizer plays an important role on the efficiency of
dye-sensitized solar cell.
Efficient Synthesis/Sintering Routes to Obtain Fully Dense ZrB2-SiC UHTC Materials
Authors: Licheri Roberta , Orrù Roberto , Locci Antonio Mario , Cao Giacomo
Published: March 2009

Two processing routes, both starting from powders of Zr, B4C and Si, which take advantage of
the Spark Plasma Sintering (SPS) apparatus, are proposed in this work for the preparation of fully dense
2ZrB2-SiC composite. The first method consists of the in-situ reaction synthesis and densification of the
product while, in the second one, reactants are first converted by SHS (Self-propagating Hightemperature
Synthesis) into the desired composite and the obtained powders are then sintered by SPS.
Based on the results reported in this work, both routes are particularly convenient as compared to the
techniques available in the literature for the preparation of analogous materials.
Temperature Dependency of Dielectric Properties in Epitaxially Grown SrBi4Ti4O15 Films with Different Orientation
Authors: Funakubo Hiroshi , Suzuki Muneyasu , Takahashi Kenji , Watanabe Takayuki
Published: March 2009

(001)-, (1110), and (105)- oriented SrBi4Ti4O15 films with its c-axis tilted 0, 45 and 55o from
the surface normal were epitaxially grown by metal organic chemical vapor deposition and the temperature
dependency of the dielectric constant was systematically investigated. Relative dielectric constant, εr,
and its temperature dependency increased when the tilting angle of the c-axis from the substrate surface
normal increased. Temperature dependency of εr was positive in case of the (105) and (1110) orientation,
which is in good agreement with the conventional ferroelectric materials. On the other hand, it became
negative for (001) orientation. This shows the orientation dependency of εr in SrBi4Ti4O15.
Fabrication of ZrO2-SUS Functionally Graded Materials by Slip Casting
Authors: He Xin , Du Hai Yan , Wang Wei , Jing Wei , Liu Chang
Published: March 2009

TZP/SUS304 functionally graded material (FGM) was developed by slip casting. Microscopic
observations demonstrated that the chemical composition and microstructure of TZP/SUS FGM
distributed gradually in stepwise way, eliminating the macroscopic ceramic/metal interface occurred in
traditional ceramic/metal joint. Each interface of layers connected well without evident defects, and the
mechanical properties of TZP/SUS system strongly depended on constitutional variation.
Preparation of Glass-Alumina Functionally Gradient Materials by Rapid Prototyping Technology
Authors: Jiang Hong Tao , Wang Xiu Feng , Yu Cheng Long , Shan Lian Juan , Deng Shuang Shuang
Published: March 2009

A novel rapid prototyping manufacturing technology for glass-alumina functionally gradient
materials (G-A FGMs) based on the quick solidification of wax was proposed. The feature of the
technology came from its layer-by-layer fabrication of the wax-glass/alumina composite layer carved in
accordance with the shape of each layer of the computer designed model and in situ casting of wax into
the carved area. Removal of the wax in the G-A FGMs green body was investigated based on differential
scanning calorimetry (DSC) analysis. Sintering properties of the G-A FGMs were discussed. Bending
strength of the G-A FGMs was measured by a three-point flexural test. Microstructures of the prepared
G-A FGMs were observed using environmental scanning electron microscope (ESEM) and the
compositional distribution was determined according to energy dispersive spectrum (EDS). Samples
were preliminarily and respectively held at 200°C and 300°C for a long time based on the DSC analysis.
The range of the optimal sintering temperature is determined to be from 710°C to 720°C and the holding
time is 30min. With the increasing alumina content, the bending strength increases and the maximum
bending strength is 67.5MPa. There is no delamination of the G-A FGMs via ESEM. Homogeneous
distribution of the ingredient materials is confirmed through EDS.
Change of Microwave Dielectric Loss during the Solid-Reaction Synthesis of SrFeCo0.5Oy
Authors: Xu Zhi Jun , Chu Rui Qing , Cui S.C. , Zhao Long Zhi , Zhang Jin Son
Published: March 2009

Rectangular cavity perturbation method was used to measure microwave dielectric loss (MDL)
during the solid state reaction synthesis of SrFeCo0.5Oy. In the process of solid state reaction, the dielectric
loss is investigated under different temperatures. The phases of the samples synthesized at different
temperatures were characterized by XRD. The variation of MDL with temperature illustrates that the
phase transformation occurs. The reasons why the pure perovskite phase can be obtained by using
microwave processing were also discussed.
Fabrication of SiC Dense-Porous Laminates by Electrophoretic Deposition Process
Authors: Li Yuan , Gao Ji Qiang , Yang Jian Feng , Wang Hong Jie , Qiao Guan Jun
Published: March 2009

In order to obtain dense-porous laminated structure in green bodies of SiC ceramics, rapid
aqueous electrophoretic deposition (EPD) was introduced. The suspension for the electrophoretic
deposition was prepared using silicon carbide, silicon and carbon powders as the starting materials.
During the electrophoretic deposition process, the intending dense and porous layers were deposited
alternately to form the green body. After drying, the green bodies were reaction-bonded at 1550°C in
vacuum atmosphere. Pore fraction of the porous layers could be adjusted by changing process preferences
of EPD and suspension composition. Pore size and size distribution could be controlled by using different
sized starting powders. Using this process, no additional substance is necessary to generate the pores via
burnt-off, and the dense/porous laminated structure can be obtained by one-step sintering process.
Preparation of Ternary Layered Ti3SiC2 Ceramic by SHS/PHIP
Authors: Bai Yue Lei , He Xiao Dong , Zhu Chun Cheng , Qian Xu Kun
Published: March 2009

Ternary-layered Ti3SiC2 ceramic was prepared by self-propagation high temperature combustion
synthesis with pseudo hot isostatic pressing (SHS/PHIP). The effect of Ti/C mol ratio, Si content and
Al content on the phase composition of the products was investigated. Experimental results showed that
the phase composition of SHS/PHIPed products was influenced greatly by Ti/C mol ratio and Si content
in the raw material. When Ti/C mol ratio is 1.5, the main phase was TiC with only a little Ti3SiC2; the
content of Ti3SiC2 increased greatly with increase of Si content. The main phase turned to Ti3SiC2 while
TiC became the main impurity when the Ti/C mol ratio arrived at 2. With addition of aluminum, the
content of Ti3SiC2 increased obviously and the distortion of lattice was caused in Ti3SiC2 crystals.
Microstructure and Mechanical Properties of Graded Materials Prepared by Field-Activated and Pressure-Assisted Combustion Synthesis
Authors: Meng Qing Sen , Chen Shao Ping , Shen Y.L. , Liu Cui Rong , Munir Z.A.
Published: March 2009

Using the processes of field-activated and pressure-assisted combustion synthesis (FAPACS),
FGM materials (FGMs) were prepared under the conditions of field-assisted and the hot-press. The
microstructure and the phase composition of the interface of the graded materials were investigated and
the results showed that the metallurgical joining layer was formed in the interfaces of the
(TiB2)pNi/Ni3Al/405 steel. The mechanical characterization of the gradient materials showed that the
composition and the micro-hardness of the gradient material were gradient distributed, and its surface
Rockwell hardness and wear resistance are better than that of hardened 20Cr steel.
Preparation of KNbO3 Powder by Modified Pechini Method from Layered Perovskite Aqueous Solution
Authors: Kokubo Takafumi , Kakimoto Kenichi , Ohsato Hitoshi
Published: March 2009

KNbO3 (KN) powder was synthesized by modified Pechini method (polymeric precursor
method). KN powder with different crystal structure and grain size distribution was synthesized by
different drying temperature. In this paper, the mechanism of preparation of KN powder was discussed in
thermal decomposition behavior. The obtained powder was characterized by XRD, TEM, FT-IR and
TG-DTA.
Preparation and Characterization of Porous Silica Obtained by Hydrochloric Acid Selective Leaching Metakaolinite
Authors: Wang Lin Jiang , Xie Xiang Li
Published: March 2009

Porous silica was prepared by selective leaching of metakaolinite with 20 mass% HCl solution.
The metakaolinite was derived from the 1:1 layered structure clay mineral kaolinite by firing at 600°C for
24 h. The characteristics of porous silica were studied. The content of Al2O3 in metakaolinite was sharply
changed from 45% to less than 2% after 2 h leaching. The maximum specific surface area of the leached
sample was about 350 m2/g. The average pore size is about 2 nm. The total pore volume is 0.3 ml/g. The
layer structure of kaolinite and metakaolinite is responsible for forming micropores.
Synthesis and Properties of Ca0.85(W1-xMox)O4:Eu0.15 Rare Earth Phosphors
Authors: Chen Y.Y. , Song C.X. , Xiong Zhao Xian
Published: March 2009

Rare earth phosphors of Ca0.85(W1-xMox)O4:Eu0.15 (x=0.00-0.50) were synthesized via solidstate
reaction in air. The lattice parameters strongly depended on the x value, which was analyzed by the
XRD patterns. Microstructures of the powders were observed by SEM. The phosphors could be
effectively excitated by ultraviolet (UV) light (250-300nm) and blue light (464nm), which were showed
with the excitation and emission spectra. With the increasing of x value, moreover, another emission peak
of the sample which was excitated by UV light appeared and shifted to short wavelength, from 597 to 545
nm. The luminescence properties of the phosphors and energy transfer mechanism were also discussed.
Influence of Liquid Phase on Grain Growth of Ba0.998La0.002TiO3 Ceramics
Authors: Pu Yong Ping , Yang Gong An , Liang Yun He , Yang Wen Hu , Wang Jin Fei
Published: March 2009

The influence of liquid phase on grain growth of Ba0.998La0.002TiO3+xmol%TiO2 (x=0~5.0)
ceramics sintered at 1350°C was investigated. The result showed that the liquid phase must present during
grain growth; on the other hand, BaTiO3 grains must be dissolved, and then, precipitated from the liquid
phase during the process of dissolution-precipitation. Otherwise, the grain growth was inhibited. The
liquid phases of Ba6Ti17O4 and Ba2TiSi2O8 promoted grain growth due to high solution of BaTiO3 grains
in the liquid phases. Ba2Ti2SiP2O13 liquid phase inhibited grain growth since BaTiO3 grains cannot
dissolve into the phase, consequently the samples showed insulating behaviour.
The Nonlinear Characteristics of Different Additives Added V2O5-ZnO Varistor
Authors: Diao Chien Chen , Chien Shih Feng , Yang Cheng Fu , Chan Hsien Wu , Chen Ying Chung , Chung Ho Hua
Published: March 2009

Most commercial ZnO varistors containing Bi2O3 exhibit excellent varistor properties, but they
have a few drawbacks due to Bi2O3 having high volatility and reactivity and higher sintering temperature.
In this study, V2O5 is added as the varistor forming oxide to lower down the sintering temperature of ZnO
varistors for the further developing the chip Varistor array by using the Ag as the inner electrode. It is
found that the sintering temperature of V2O5-added ZnO will be lower down to about 600oC. But the
addition of V2O5 has no improvement in the electrical characteristics, and they need many additives to
obtain the high performance. For that, the nonlinear properties in these Varistors can be improved by
incorporation of some oxide additives. Different MnOx oxides (MnO, MnO2, and Mn3O4) and CoOx
oxides (CoO and Co3O4)are used as the minor oxide additives. The influences of different MnOx and
CoOx oxides on the nonlinear voltage–current density (V-I) characteristics and the nonlinear exponent (α)
of V2O5-ZnO varistor will be well developed.
Investigation on the Effects of Zn on PbTiO3
Authors: Garcia J.A. , Herrera M.U.
Published: March 2009

Synthesis of Zn-doped PbTiO3 was done using solid-state method. The effects of varying amount of Zn were investigated. Stoichiometric amount of precursors were mixed and ground. The pressed mixtures were calcined at 800°C and sintered at 1,100 °C after regrinding. The samples were characterized using X-ray Diffraction (XRD), Differential Thermal Analysis (DTA), and Scanning Electron Microscopy (SEM). The XRD verifies the existence of PTO in the samples. DTA shows the thermal profile of the samples. Among the different concentrations of Zn that were added, the sample with 5% mole fraction showed the lowest melting point. For 5% mole fraction and greater, SEM images showed flattening and fusing of grains.
A New Model for Simulating AC and Surge Properties of ZnO Varistors Based on Microstructural Characteristics
Authors: Hu Jun , He Jin Liang , Luo Feng Chao
Published: March 2009

The numerical simulation is an effective method for researching the relationship between
macroscopic properties of ZnO varistors and their microstructural characteristics. However, the
computing efficiency is a big problem for further researches. In this paper, a quick piecewise linear
method for solving the complicated nonlinear resistor networks of ZnO varistors is proposed, which can
significantly improve the computing efficiency by a hundred times. The simulating models for the
microstructural characteristics of ZnO varistors are improved based on actual conduction mechanism of
grain boundaries. The simulations of more bulk characteristics of ZnO varistors become possible, such as
alternating current (AC) and surge properties.
Microstructures, Properties and In Situ Toughening of Rapidly Solidified Al2O3/YSZ Composite Ceramics Prepared by Combustion Synthesis
Authors: Zhao Zhong Min , Zhang Long , Song Yi Gang , Wang Wei Guo
Published: March 2009

The large-scale Al2O3/YSZ ceramic plates were prepared by combustion synthesis under high gravity, the ceramics were mainly composed of random-oriented rod-shaped grains, and within the rod-shaped grain aligned nano-submicron YSZ fibers were embedded. Compared to the high-performance directionally solidified ceramics, the hardness, flexural strength and fracture toughness of the eutectic ceramics obtained in the experiment increased by 40.7~55.1%, 9.6~26.0% and 172.0~240.0%, respectively. The increase in hardness and strength of the ceramics could be attributed to nano-submicron YSZ fibers and inter-phase spacing and the refinement of the eutectic grains; meanwhile, high-energy, large-angle boundaries between rod-shaped grains could introduce strong toughening mechanisms involving crack-bridging and pull-out of rod-shaped eutectics.
Properties of SiC/Fe Composites Prepared by Coating Process and Powder Metallurgy Method
Authors: Shao Gang , Wang Hai Long , Shao Fang , Li Kai , Zhang Rui
Published: March 2009

SiC particulate-reinforced Fe composites were prepared by a powder metallurgy (PM) and
conventional atmospheric sintering method. X-ray diffraction (XRD), scanning electron microscopy
(SEM) techniques were used to characterize the obtained composites. The coating layer of Cu on SiC
particles can suppress the reaction between SiC and Fe until 1250oC. The maximum microhardness of
283 Hv appears at near 1250oC. Substantial reaction occurs at above 1250oC, which leads to the
deterioration in the microstructure and related properties. The inter-metallic compounds of FeSi or Fe2Si
were detected which contributed to the enhancement of the interface between SiC and Fe.
Selective Laser Sintering of Si3N4 and Al2O3 Ceramic Powders
Authors: Zhao Jing , Cao Wen Bin , Li Jiang Tao , Han Zhao , Li Yan Hong , Ge Chang Chun
Published: March 2009

Selective laser sintering (SLS) of Si3N4 and Al2O3 powders were investigated in this work. Copolymer was synthesized through monomer MMA and BMA. Infrared spectrum was employed to characterize the as-synthesized copolymer. Results show that the main compositions of the copolymer are PMMA and PBMA. The binders were prepared by mixing the copolymer and the inorganic NH4H2PO4 with certain ratio. Binders were used to coat the Si3N4 and Al2O3 powders by spray drying. The coated powders were sintered successfully by SLS to make cubic part and rotor part.
Si3N4-BN-SiO2 Based Microwave-Transparent Materials
Authors: Zhang Wei Ru , Wang Chong Hai , Li Ling , Liu Jian , Chen Wen
Published: March 2009

The Si-B-O-N microwave-transparent materials were prepared by gas pressure sintering
(GPS).The effect of BN and nano-SiO2 contents on the mechanical and dielectric properties of the
composites was studied. The microstructural characteristic and reinforced mechanism of the composites
were also investigated. The results showed that a series of Si-B-O-N wave-transparent materials could be
obtained by controlling the contents of raw materials and technological parameter. The bending strength
of composites is from 74.7MPa to 174.83MPa, the dielectric constant is from 3.5 to 4.2 and the tangent of
loss angle is from 0.5×10-3 to 4.5×10-3.
Preparation of SiOC Foam Ceramics Using Polysiloxane
Authors: Liu Hong Li , Zhong Wen Wu , Mao Yang Wu
Published: March 2009

The SiOC foam ceramics were prepared using polyurethane sponge and polysiloxane as raw
materials. The effects of the pyrolysis temperature, the concentration of polysiloxane solutions, and the
content of SiC nano-powder on compression strength of the SiOC foam ceramics have been investigated
respectively. The optimum compression strength of SiOC foam ceramics is obtained at the pyrolysis
temperature of 1250°C and the concentration of solution PSO of 0.8 g/ml. Adding SiC nano-powder into
PSO can effectively increase compression strength of samples, and the maximum compression strength,
20.8 MPa, is obtained when the content of SiC nano-powder is 5 wt%. Microstructural study reveals that
the foam ceramics have an open, uniform and interconnected porous structure with high porosity of 80%.
Microstructure and Properties of AlN Matrix Composites Fabricated by Reaction Synthesis
Authors: Jia Tie Kun , Wang Wei Min , Fu Zheng Yi , Wang Hao
Published: March 2009

Based on the nitridation reaction of aluminum with boron nitride (BN), aluminum nitride
(AlN) matrix composites were fabricated by reaction synthesis technique. The effect of the amount of Al
on the microstructure and properties was investigated. The bending strength, thermal conductivity and
dielectric constant increase with the content of aluminum. A heat-treatment schedule was performed to
investigate the effect of the microstructure on the properties. The results showed that the heat-treatment
leads to the grain growth and thermal conductivity increase with the grain growth.
Material Design of Transition Metal Nitrides for Hard Coatings by Metal and Nonmetal Atom Substitution
Authors: Suzuki Tsuneo , Inoue Jun , Asami Hiroki , Ibi Tomoya , Nakayama Tadachika , Suematsu Hisayuki , Niihara Koichi
Published: March 2009

Cr-Me-N-O (Me; Ni, Cu and Mg) thin films have been designed and successfully prepared
by the pulsed laser deposition (PLD) method. It was found that Me, which form the monoxide MeO,
are effective for hardening the Cr(N,O) thin films.
The Influence of the Magnetic Field Arrangement on the Titanium Oxide Films Properties for Four Targets Closed-Filed Unbalance Magnetron Sputtering
Authors: Qi Feng , Leng Yong Xiang , Sun H. , Huang Nan
Published: March 2009

The magnetic filed arrangement of unbalance magnetron sputtering can be changed
employed to expand the plasma region and induce more ions to bombard the films for fabricating
excellent quality films. In this paper, four targets closed-filed unbalance magnetron sputtering was
introduced, the effect of the different magnetic field arrangement on the titanium oxide films
properties was investigated. By changing the distance from target to vacuum center, the different
unbalance state of the magnetic field was formed around the substrate. The titanium oxide films were
synthesized at different unbalance state of the magnetic field. The microstructure of the titanium
oxide films was studied by X-Ray Diffraction (XRD), and the residual stress measurement for the
films was determined by grazing incidence XRD. The results revealed that the higher unbalance of the
magnetic field around the substrate, the higher ion current of the substrate. Comparing with increasing
the substrate bias voltage, the ion current increased 2~4 times through changing magnetic field
arrangement to induce higher unbalance of the magnetic field. Ion/atom ratio increase was in favor of
rutile phase formation for titanium oxide film. The unbalance state increase resulted in more higher
compressive stress in the films.
Preparation and Characterization of Ni-Al-Cr3C2 Coating
Authors: Du Ling Zhong , Zhang Wei Gang , Zhang Deng Jun , Li Bao Hou
Published: March 2009

In order to improve the surface properties of the machine parts, the NiAl cladding Cr3C2
powder were flame and plasma sprayed. The morphology, microstructure, composition and wear
properties of the coatings were examined. The results show that due to the exothermal reaction of the
Ni and Al elements, the bonding strength of the coatings are improved, and the main compositions of
the coatings are Ni3Al inter-metallic compound and Cr3C2. The flame sprayed and plasma sprayed
coatings show almost the same micro-hardness and friction coefficient. But the microstructure of the
plasma sprayed coating is more compact than that of the frame sprayed one and the wear resistance of
the flame and sprayed coatings is 30% and 120% higher than that of the 1045 steel, respectively. The
main wear mechanisms of the coatings are plastic deformation and spallation, and the high bonding
strength and the uniformly distributed Cr3C2 particles play important anti-wear roles.
The Study of the Electrochemical Graining Process in NaBO2- H3BO3 Solution and Grain Appearance on the Surface of Aluminum Alloy
Authors: Liu Jun Quan , Wang Xiao Hui , Xu Jin L.
Published: March 2009

The mainly process of electrochemical graining on 6063 aluminum alloy included graining
at alternating current, anodizing and chemical coloring. The graining used NaBO2- H3BO3 system as
film-forming solution, proper AC current density, treating time, temperature , adding agents and
solution concentration were ascertained through operating orthogonal experiment, the grain of
appropriate density and width could be obtained, the grained surface of aluminum alloy presented
intergranular corrosion in the graining zone, the appearance was improved after anodizing, enough
thick anodizing film could make intergranular corrosion eliminated. Cyclic voltammetry experiment
was used to preliminarily explaine the grain process, the main cause of graining zone formation was
hydrogen evolution.
Sediment Co-Deposition of Nanostructured Ni-Al2O3 Composite Coatings
Authors: Feng Qiu Yuan , Li Ting Ju , Yue Hong Yun , Bai Fu Dong , Qi Kai , Jin Jun Ze
Published: March 2009

Nanostructured Ni-Al2O3 composite coatings incorporated with various contents of
α-Al2O3 nano-particles were prepared on mild steel by using novel sediment co-deposition (SCD)
technique. For the comparison reason, the pure Nickel coating and the Ni-Al2O3 composite coatings
were fabricated by means of conventional electroplating (CEP) technique. The electroplating was
carried out in Watt’s bath without any additives except for nano-α-Al2O3 suspension. The influence
of the nano-particulates concentration, current density, and the mode of electroplating on the
composite coatings were investigated. The results reveal that the weight percent of nano-Al2O3
increases with increasing nano-α-Al2O3 concentration in plating bath and some agglomeration
occurs on the surface of composite coatings. The current density affects the alumina content in the
composite coatings as well. The nano-α-Al2O3 incorporation by the SCD technique is higher than
that of the CEP technique. The microhardness increases, while the wear rate decreases with
increasing content of the nano-Al2O3 in the composite coatings. The incorporation of nano-α-Al2O3
particles changes the surface morphology of Ni matrix and modifies the texture of composite
coating to exhibit a preferentially (111) growth orientation. Moreover, the co-deposited nano-sized
α-Al2O3 particles are uniformly distributed in the Ni matrix and contributed to remarkably increase
the microhardness, and tribological properties of the Ni base coating.
The Effect of Substrates on Properties of Anodic Coatings Formed on Mg and Mg Alloys
Authors: Zhang Rong Fa , Shan Da Yong , Han En-Hou
Published: March 2009

Substrates have major effects on coating properties. In this paper, pure magnesium,
AZ91HP and Mg-Li were separately anodized in a neutral anodizing solution containing hydrofluoric
acid, phosphate acid and borate acid. The coating properties such as surface morphology, thickness
and compositions were separately observed and detected. The behavior of voltage with time indicated
that reaching the same final voltage under the same electric parameters, anodizing time for AZ91HP
was the shortest and Mg-Li the longest. The uniformity of anodic coatings formed on AZ91HP was
the best and Mg-Li the worst. Analysis by EDX, the phosphorus content of anodic coatings formed on
Mg-Li was the highest and that on AZ91HP the lowest. Alloying elements of aluminum and lithium
slightly decreased and considerably increased the coating thickness, respectively. The effects of
lithium and aluminum on coating properties can be explained by different moving speeds of Mg2+,
Al3+ and Li+ as well as Pilling-Bedweorth ratios (PBRs) of MgO/Mg, Al2O3/Al and Li2O/Li.
The Study on the Deposition Efficiency of Microarc Oxidation on Aluminum Alloy
Authors: Yan Zhi Jun , Zhu Xin He , Cheng Dong , Gao Yu Zhou , Yan Li
Published: March 2009

With excellent wear resistance and corrosion resistance of films, simple procedures, high
production efficiency and being environmentally friendly, micro-arc oxidation has become a novel
technique to produce ceramic coatings on the surfaces of light metals such as aluminum and its alloys.
In order to decrease the electric power consumption during the process, we put forward a improved
technique of micro-arc oxidation, and introduce its technical properties and treatment effects on the
surfaces of aluminum. The experimental results show that the properties, such as phase structure,
thickness, roughness and hardness of the ceramic coating prepared by improved micro-arc oxidation
are similar to those prepared by traditional micro-arc oxidation. The micro-arc oxidation with higher
deposition efficiency will be an important research direction in the future.
Electrodeposition of Aluminum on 316L Stainless Steel from Molten Salts Based on Chlorides
Authors: Wang Yu Jiang , Ma Xin Xin , Guo Guang Wei
Published: March 2009

The electrodeposition of aluminum on 316L stainless steel from a molten salts based on
chloride has been studied. The surface morphology of the aluminum layer has been examined through
scanning electron microscope (SEM) and the structure of the aluminum layer has been analyzed by
X-ray diffraction (XRD). The thickness of the deposited aluminum layer has been measured by the
method of cross-section scan. It has been suggested that a white, smooth, non-porous and a high purity
aluminum layer can be obtained on 316L stainless steel from the ternary chloride molten salts (AlCl3
– NaCl - KCl). And the structure of the aluminum layer was single-phase.