bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Magnetic Property of Bi2Fe4O9 Nanoparticles by Hydrothermal Method
Authors: Miao Hong Yan , Yu Zhi Wei , Tan Guo Qiang
Published: March 2009

Bi2Fe4O9 nanoparticles were prepared at low temperature via a facile, one-step hydrothermal synthesis process using iron(III) nitrate nonahydrate (Fe(NO3)3•9H2O) and bismuth nitrate pentahydrate (Bi(NO3)3•5H2O) as starting materials and sodium hydroxide (NaOH) as precipitant and mineralizer. XRD results indicated that the as-prepared nanoparticles are pure orthorhombic Bi2Fe4O9. SEM images revealed that the as-prepared Bi2Fe4O9 nanoparticles have a sheet-like morphology. They are paramagnetic at room temperature demonstrated by the magnetic measurements.
Effect of Carbon Source on In Situ Carbothermic Reduction Fabricating Steel-Bonded Cemented Carbide GT35 from Ilmenite
Authors: Wu Yi , Wang Xin , Long Fei , Shen Yu Fang , Zou Zheng Guang
Published: March 2009

In the present study, steel-bonded cemented carbide GT35 has been fabricated from natural
ilmenite by in-situ carbothermic reduction and vacuum pressureless sintering. The effect of different
carbon source on the mechanical properties and microstructure of GT35 composite was studied. The
quality of the composite synthesized from natural graphite is higher than those from other carbon source.
Some good results were obtained from experiments: the density is about 6.2g/cm3, and the bending
strength is 1390MPa, which higher than that of other samples. The structures and ingredient of different
carbon source were analyzed to elucidate their different performance in the reactions.
Biomineralization Properties of Polyvinyl Alcohol/Bioglass Biocomposite Hydrogels
Authors: Wang Ying Jun , Xu Hong , Ren Li , Zheng Yu Dong , Chen Xiao Feng
Published: March 2009

In order to form the firm active fixation with the adjacent bone, a new kind of bioactive
composite hydrogel was prepared as calcic layer of cartilage with polyvinyl alcohol (PVA) and bioglass
(BG). The biomineralization properties of the PVA/BG biocomposite hydrogel were studied through
Fourier transformed infrared spectroscopy, XRD and SEM with EDX. Results showed that hydroxylcarbonateapatite
was formed on the surface of the PVA/BG biocomposite hydrogel after the biocomposite
hydrogel soaked into SBF solution. The composite possesses good mineralization properties and could
form good firm active fixation with the adjacent bone.
Study on Dental Colored Zirconia Restoration
Authors: Wen Ning , Yi Yuan Fu , Zhang Wei Wei , Liu Hong Chen , Shao Long Quan , Deng Bin , Tian Jie Mo
Published: March 2009

This paper explored the color and mechanical properties of CeO2 and Er2O3 shaded zirconia
ceramics for dental application. Twelve kinds of colored dental ZrO2 powders were prepared.
Experimental results showed that the hue of the materials shift from yellow-green to yellow-red with the
increasing concentration of the CeO2 and Er2O3, while reducing of the brightness( L* ) value was little.
Three-point bending strength decreased form 1209MPa to 845MPa after coloring, which was lower than
the uncolored materials (1301MPa). The fracture toughness decrease slightly. SEM observation revealed
more porous microstructure in specimen containing both two additives. Cerium oxide and erbium oxide
are candidates of color additives for shading dental zirconia ceramics.
Hydrothermal Electrophoretic Deposition of Yttrium Silicates Coating on SiC-C/C Composites
Authors: Zhang Yu Tao , Huang Jian Feng , Cao Li Yun , Deng Fei , Wu Jian Peng
Published: March 2009

Yttrium silicates coatings were deposited on SiC-C/C composites surface by a hydrothermal electrophoretic process using yttrium silicates nano-crystallites, isopropanol and siodine as source materials, solvent and charging agent, respectively. The yttrium silicates nano-crystallites were preprepared by a sonochemical process. The influence of deposition temperatures on the microstructures and crystallization of the yttrium silicates coatings were investigated. Surface and cross-section microstructures of the as-prepared multi-coatings were characterized by XRD and SEM. Results show that the coatings are composed by yttrium silicates crystallites with the main phase of Y2Si2O7 and a little Y2SiO5. The thickness and the density of the yttrium silicates coatings increases with the increase of deposition temperatures; and the coating process has little influence on the phase compositions of the coatings.
Ceramic Coatings on Graphite via Polymer Vapor Pyrolysis Deposition Process
Authors: Xing Xin , Liu Lin , Huang Xiao Zhong , Li Xiao Dong
Published: March 2009

Silicon carbide coatings on graphite were prepared through polymer vapor pyrolysis deposition process (PVPD) under N2 atmosphere. During this process, some low molecular weight substances that polycarbosilane (PCS) pyrolyzed can be deposited on graphite, and they can convert into SiC in high temperature. The results of XRD showed that amorphous SiC coatings were formed on graphite when the pyrolysis temperature was 1000°C, andβ-SiC phase formed in the coatings when the temperature up to 1250°C. Effects of the coatings on the microstructure and properties were investigated. It was shown that the uniform dense SiC coatings could be obtained by carefully controlling the pyrolysis temperature and ramping rate when the number molecular weight of PCS was in the range of 1,000~1,500.
Thermal Conductivity of (La0.5Sm0.5)2(Zr0.9Ce0.1)2O7 Ceramic for Thermal Barrier Coatings
Authors: Zhang Hong Song , Xu Qiang , Wang Fu Chi , Liu Ling
Published: March 2009

Pyrochlore structure oxide (La0.5Sm0.5)2(Zr0.9Ce0.1)2O7 was prepared by mixing the appropriate amounts of ZrO2, La2O3, Sm2O3 and CeO2, followed by reacting at 1600°C for 10 h. It was shown that the thermal conductivity was much lower than that of 8YSZ, which was mainly ascribed to the oxygen vacancies and lattice strain in lattice of (La0.5Sm0.5)2(Zr0.9Ce0.1)2O7.
Pressure-Dependent Characteristics and Properties of Al2O3-SiO2 Thin Films Deposited on PET
Authors: Huang Hong Hsin , Liu Yuan Shing , Yang Cheng Fu , Chen Yen Ming , Chen Cheng Yi , Wang Moo Chin
Published: March 2009

Transparent and hard Al2O3-SiO2 thin films have been deposited on PET substrate by E-beam
evaporation with oxygen pressure ranging from 1×10-5 to 1×10-3 Torr at room temperature. Pressuredependent
characteristics were analyzed by X-ray diffraction (XRD), scanning electron microscopy
(SEM) and energy dispersive spectrometry (EDS), meanwhile, apparent transmittance and hardness of
thin films were evaluated by uv-visible spectroscopy (UVs) and nanoidentor, respectively. The XRD
results showed that the amorphous Al2O3-SiO2 film was obtained although the intensity of the broaden
peak decreased with oxygen pressure increasing. The similar morphologies and composition were
obtained in pressure range. Good apparent transmittance was found, which higher than 85% in the
pressure range. Apparent hardness of PET was effectively improved from 2.77 to 5.7 – 6.1 GPa depending
on oxygen pressure. However, the critical load of Al2O3-SiO2 film slightly decreased with oxygen
pressure increasing.
Fabrication and Characterization of Bioactive Cancellous-Like Surface on Titanium
Authors: Tian Yi Ping , Wei Shan Shan , Li Hui , Guo Ling Hong
Published: March 2009

Bioactive porous surface on metal implants are benefit for forming the continuous interface
with “mechanical interlocking” and “chemical bonding” between implants and bones. In the present
study, the main attention was concentrated on fabricating a porous bioactive surface on Ti substrate.
Porous surface was first fabricated by two-step etched. Then thin HA coating was deposited on the
pre-treated porous Ti surface by sol-gel method and immediately sintered at 500°C for 1 hour. The
structure and morphology of HA coating formed on the porous surface were characterized by thin-film
X-ray diffrac- tion and scanning electronic microscopy, respectively. Rietveld method and
Warren-Averbach Fourier Transfer Analysis were employed to determine the lattice parameters,
crystallite size and micro-strain of HA coating. The SEM results indicated that an interconnecting porous
surface with cancellous structure and mean diameter about 1/m was etched on the Ti substrate, and the
surface was covered by a thin particle coating. The TF-XRD results testified that the thin coating was poor
crystalline HA.
Preparation and Characterization of the Ordered SiO2 Colloidal Crystallization Films
Authors: Qing Shuan Gui , Liu Bo , Liang Xun , Li Hai Yang , Lv Wei Zhong , Cai Hong Hua , Wang Fang , Luo Zhong Kuang
Published: March 2009

Multilayer SiO2 crystals modified by alkoxysilanes were fabricated by the vertical deposition
technique combined with self-assembly method. The SiO2 colloidal crystallization was prepared by the
traditional Stöber-Fink-Bohn method, and modified by different alkoxysilanes to investigate the
properties of the films. The films fabricated by the ordering of SiO2 spheres were investigated by infrared
spectrometer, X-ray diffraction, scanning electron microscope, UV-visible spectrophotometer. The
results showed that thin film is the face-centered cubic structures and the spheres are [111]-oriented.
Preparation and Morphological Controlling of Nanophase NaNbO3 by Sol-Gel Method
Authors: Lin Ying , Yang Hai Bo , Wang Fen
Published: March 2009

With citric acid as chelating agent, ethylene alcohol as etherification agent and water as
solvent, NaNbO3 nanopowder was synthesized by citrate sol-gel method. The effects of amount of CA
and EG, pH value on the stability of the precursor sol were investigated. The evolution of NaNbO3 crystal
phase was also investigated by XRD and TG-DTA. The results showed that a homogeneous precursor sol
was formed at in the case of n(CA) : n(metal ion)=3:1, n(CA) : n(EG)=1: 2 and 1:3 and pH=7.5. Sintering
process largely influences the morphology of the prepared products. Grain-like nanoparticles could be
obtained with a rapid temperature rising rate, while nanorods were obtained with a slow rate. The forming
mechanism of different morphologies of the prepared nanoparticles was also discussed.
A Novel Technique for Viewing Stress Distribution with Mechanoluminescence Materials
Authors: Li Chen Shu , Xu Chao Nan , Yamada Hiroshi , Imai Yusuke , Zhang Hong Wu , Zhang Lin
Published: March 2009

We have successfully demonstrated that the stress distribution of a metal substrate can be
directly displayed by coating SrAl2O4:Eu (SAO), a representative of strong mechanoluminescent
materials, on the surface of test objects. An aluminum plate with SAO sensing film had been applied to
experimental analysis of stress concentrations, and a numerical calculation via a finite element method
confirmed that the observed real time mechanoluminescence images displayed the stress distribution. As
a result, visualization of stress distribution on metal surface has been realized by ML images using SAO
sensing film, and this novel visualization technique can be applied for viewing the stress concentration in
various fields such as modeling, manufacturing and demonstration of an industrial product.
Preparation and Photocatalytic Property of WO3-TiO2 /Ti Ceramic Film via Anodic Oxidation Treatment
Authors: Jiang Yan Li , Liu Hui Ling , Jiang Zhao Hua , Yao Zhong Ping
Published: March 2009

The high efficient WO3-TiO2/Ti ceramic film was prepared on the surface of titanium by the
approach of anodic oxidation in order to make the absorbable spectrum of catalyst spread to the visible
region and restrain the high recombination rate of electron-hole pairs during photoreaction. The surface
morphology and the distribution of elements were studied with scanning electron microscopy and energy
dispersive spectroscopy. The phase composition of the films was investigated with XRD. The results
showed that the main components in the coating were WO3, rutile TiO2 and anatase TiO2. The compound
WO3-TiO2/Ti ceramic film enlarged the range of the reacting visible light and increased the absorbing
intensity. The rhodamine B was successfully photodegraded under visible light irradiation by
WO3-TiO2/Ti catalyst films. It was found that the highest degradation rate of rhodamine B was achieved
through an optimal W dosage of 4.2 %(wt %) in WO3-TiO2/Ti ceramic film. It was also confirmed that the
recombination rate of electron-hole pairs in WO3-TiO2/Ti ceramic film declined due to the existence of
WO3 in TiO2/Ti ceramic film.
Layered and Graded Coatings as Plasma Facing Materials for Fusion in LSCPM
Authors: Song Shu Xiang , Zhou Zhang Jian , Yao Wei Zhi , Cong Wei Wei , Ge Chang Chun
Published: March 2009

This paper reports some new progresses on layered and graded coatings for plasma facing
materials in fusion devices in Laboratory of Special Ceramics and Powder Metallurgy (LSCPM),
University of Science and Technology Beijing (USTB), China. They included tungsten coatings made be
various particle sizes of initial feedstock and interlayers and boron carbide graded coatings. All the
coatings were fabricated on the oxygen free copper by plasma spraying. The microstructures and
properties were investigated for PFM. Water quenching and high heat loading experiments were also
carried out to estimate the thermal performance of these coatings.
A Stepwise Control Route for the Preparation of Mg-Al, Zn-Al, and Mg-Fe Layered Double Hydroxides (LDHs)
Authors: Liu Zhao Hui , Gu Xiao Hua , Zhang Zhao Cai , Wang Dan , Yin Cui Yu , Shen Xin Yuan
Published: March 2009

Mg-Al, Zn-Al, and Mg-Fe layered double hydroxides (LDHs) have been synthesized through a
stepwise control route. In the stepwise control route, we controlled the state of Al or Fe composition as Al
or Fe hydroxyl aqueous complexes in aqueous solution first, then dropwise Mg2+ or Zn2+ and OH
-
and
keep procedure at constant pH value simultaneously at room temperature. The textural and structure
properties of the resulting samples were characterized by XRD and TG-DTG. The results showed that
products obtained by the stepwise control route were pure and highly crystalline LDHs. The particle size
and size distribution was measured by DLLS.
Cladding of WC-Cr3C2 Cermet Coating by Laser Controlled Reactive Synthesis
Authors: Li Wen Ge , Zhang Guang Jun , Li Jun
Published: March 2009

WC-Cr3C2 cermet coating on carbon steel was fabricated by laser controlled reactive synthesis
method. Effect of diluents is the key factor influencing the cladding process. When the amount of diluents
is 30%, the reaction becomes steadily and the smooth coating can be achieved. Observations of the
microstructure and phase composition of the sample showed that the coating was a complex phase system
which consisted of WC and Cr3C2. In order to improve bond strength of the coating, Ni was selected as
additive. The interface morphology showed that the bonding between coating and substrate was
metallurgical bonding.
Piezoelectric and Dielectric Properties of (Bi0.5Na0.5)0.94(Ba1-xSrx)0.06TiO3 Lead-Free Piezoelectric Ceramics
Authors: Chen Zhi Wu , Lu Zhen Ya , Hu Jian Qiang
Published: March 2009

Lead-free piezoelectric ceramics (Bi0.5Na0.5)0.94(Ba1-xSrx)0.06TiO3 (abbreviated as
BNBST-100x, with x ranges from 0.02 to 0.1) have been investigated. Effects of amount of
Sr-substitution on the electrical properties and crystal structure of the ceramics were studied. The
BNBST-100x ceramics sintered at 1200°C for 2h in air have high density around 5.69~5.75g/cm3. X-ray
diffraction (XRD) analysis shows that all of the BNBST-100x ceramics have pure perovskite structure. At
high amount level of Sr-substitution, the crystal structure of the samples changes from rhombohedral to
tetragonal symmetry. Piezoelectric and dielectric measurements reveal that Sr-substitution amount within
a certain range will lead to the increase of piezoelectric coefficient (d33), electromechanical coupling
factor (kp), and relative dielectric constant (ε33
T/ε0). At 6 mol% Sr-substitution level, the d33 and kp of the
ceramics reach maximum, with values of 168 pC/N and 34%, respectively.
Grain Growth and Electric Properties of Lead-Free BaTiO3 Ceramics
Authors: Wang Chun Huy
Published: March 2009

Many lead-free materials, such as Bi-based compounds, BaTiO3 or alkaline niobate compound,
have been intensively studied. The microstructure and characteristics of BaTiO3 ceramics are
significantly influenced by addition of 4PbO-B2O3. Under low sintering temperatures, the grain growth of
BaTiO3 ceramic is enhanced by capillary action, rearrangement and solution-reprecipitation of the liquid
phase. At high sintering temperatures, exaggerated grain growth of BaTiO3 ceramic is restrained by the
presence of a liquid phase. The theory of grain growth in the presence of a liquid phase is examined in
terms of the equation Rn = k× t. The grain growth kinetic exponent, n, has an inverse relationship with the
rate of grain growth. With suitable amounts of glass frit and an optimized sintering temperature, the
density is enhanced and the values of the dielectric and piezoelectric properties are improved.
Preparation and Characterization of Gd1-xSrxCoO3-δ
Authors: Wang Yan An , Guan Xiang Feng , Zhou He Ping , He Ying
Published: March 2009

GdSrCoO3-δ and Gd1-XSrXCoO3-δ (x=0.1~0.5) were synthesized using glycine-nitrate process
(GNP). The formation process of perovskite phase and microstructure of powders were characterized
using TG-DTA and XRD. All the powders with different doping amounts of Sr2+ on A-site were
single-phase solid solutions, and the stable perovskite phase was formed completely after calcination at
1100°C. The crystal structures of the solid solutions transfer to a higher symmetrical perovskite.
Elastico-Luminescent Nanoparticles Prepared via Polymer-Coated Precursor Formed in Reverse Micelles
Authors: Li Cheng Zhou , Adachi Yoshio , Imai Yusuke , Nishikubo Keiko , Xu Chao Nan
Published: March 2009

Europium-doped strontium aluminate is a famous green phosphor that can give luminescence
under a mechanical stress that is named elastico-luminescence. This paper reports a modified reverse
micelles process for preparing the europium-doped strontium aluminate nanoparticles. A polymeric
matrix was coated on the surface of the precursor formed in the reverse micelles. The polymeric matrix is
considered to prevent the particle agglomeration by forming a carbon layer while the precursor was
heat-treated. Consequently, the luminescent nanoparticles were achieved after removing the carbon layer
and forming the luminescent center under a reducing atmosphere. The processing and properties of the
luminescent nanoparticles were discussed in this paper.
Preparation of Upconversion Luminescent NaYF4 Co-Doped with Yb3+/Er3+ via Hydrothermal Synthesis
Authors: Cheng Chang Hua , Wu You Na , Xiong Zhao Xian
Published: March 2009

Hexagonal NaYF4 crystals co-doped with different concentration of Yb3+ and Er3+ ions were
synthesized via hydrothermal reaction route. The samples doped with 30mol% of Yb3+ and 1mol% of Er3+
showed the highest upconversion efficiencies under 980nm excitation. Powder X-ray diffraction (XRD)
analyses indicated that the samples were pure hexagonal phase. The morphology of the powder was
observed by scanning electron microscopy (SEM). With the excitation of a 980nm diode laser, strong
green emissions were obtained at 522, 530, 542 and 551nm in addition to weak red emission at 654nm.
The green and red emissions were attributed to the transitions of 4S3/2, 2H11/2 → 4I15/2 and 4F9/2 → 4I15/2 of
Er3+ ion, respectively. The additions of Yb3+ ion as sensitizer can notably enhance the upconversion
efficiencies from infra-red to visible. The upconversion mechanism of the emission for the samples was
also discussed.
Influences of Twin Boundaries on Microstructural Characteristics of ZnO Varistors Simulated by Voronoi Network
Authors: He Jin Liang , Hu Jun , Luo Feng Chao
Published: March 2009

The presence of twins in ZnO varistors raises interesting questions concerning the potential role of those electrically distinctive twin boundaries in the characteristics of ZnO varistors. The paper uses Voronoi networks to simulate the microstructures of ZnO varistors. The relation between the relative standard deviation of grain size and the ratio of twin number to grain number is obtained. It indicates that the relative standard deviation decreases with the increasing of the twin ratio. On the other hand, ZnO varistor samples with different content of Al2O3 additive were prepared to gain different twin ratios. The simulation has the same conclusion as that obtained from experiments. The probable mechanism of ZnO grain growth inhibition by twins is that the twins increase the mobility viscosity of ZnO grains and grain boundaries, and drag ZnO grains and liquid grain boundaries during the sintering course, then the grain growth is inhibited, and the microstructure becomes more uniform.
Influence of Pr6O11 on the Characteristics and Microstructure of Zinc Varistors
Authors: Zhu Jian Feng , Gao Ji Qiang , Wang Fen , Chen Ping
Published: March 2009

The influence of the amount of Pr6O11 additions on the microstructure and electrical properties
of varistors ceramics in the ZnO-Bi2O3 system was investigated. Samples with a low level of Pr6O11
(0.1wt %) have high microstructural homogeneity, which enhances the nonlinear coefficient greatly, and
decreases the leakage current without change of voltage ratio. When the Pr6O11 content reached 7wt%, the
ZnO grain growth was restricted and the threshold voltage was improved from 275v/mm to 440v/mm.
The additive of Pr6O11 changed the process of creating spinel phase, which came from the decomposition
of pyrochlore phase. This type of small size phase has more dragging force on the ZnO crystal, which
make the whole materials more uniform and compact.
Properties and Numerical Simulation of Electromagnetic Meta-Materials (SRR) Based on Ceramic Substrate
Authors: Du Bo , Zhao Q. , Zhou Ji , Kang L.
Published: March 2009

Electromagnetic meta-materials are artificial and periodical materials which both the permittivity and permeability are simultaneously negative. Electromagnetic meta-materials represent a new concept where composite materials are designed to display particular properties. The work which we had finished includes theoretical design and numerical simulation of the structure, fabrication of the samples and measurement of the properties. We designed electromagnetic meta-materials which composed by periodic split ring resonators (SRR) based on ceramics and then researched the influence by microwave guide. It is showed that the resonance frequency of meta-materials can be adjusted by dielectric constant and thickness of ceramic substrate.
Solid Phase Synthesis and Sintering Properties of Yttrium Iron Garnet
Authors: Fang Ming Hao , Huang Jun Tong , Huang Zhao Hui , Liu Yan Gai , Jiang Bin , Peng Peng
Published: March 2009

Single phase YIG powders were synthesized successfully using Fe2O3 and Y2O3 as starting materials by solid state reaction, and YIG ceramics were prepared by pressureless sintering. The influence of synthesizing temperature and Fe2O3 content on the final production were studied The effect of Fe2O3 content on volume density and microstructure of the sintered YIG was also investigated. The results showed that single phase YIG powders were synthesized by solid state reaction at 1400°C for 3h. When Fe2O3 content was excessive 3 wt%, YIG ceramics with a density of 5.294g·cm-3 was fabricated by sintering at 1480°C for 2.5h.
Study on the Opening and Modifying of MWNTs
Authors: Zhang Na , Sun Jing , Zhang Min , Yu Jia Lin , Li Qiang
Published: March 2009

Different opening and modifying methods of MWNTs are studied and compared in this paper.
MWNTs are dipped in a refluxed HNO3 solution. The influence of temperature, concentration and
holding time on the opening and modifying of MWNTs is studied. The compared process is that MWNTs
are treated by O3. The solvent that can highly dissolve O3 and disperse MWNTs is crucial. In order to
prompt the reaction, 1M CF3COOH is elected as reactant medium and catalysis. The opening of MWNTs
is tested by BET and confirmed by TEM. The surface structure of MWNTs treated by different processes
is analyzed by FT-IR. The optimum conditions of opening and modifying of MWNTs are discussed.
Controlling Porosity and Pore Size Distribution of Alumina Ceramics in Consolidation Forming Process Using Modified Starches
Authors: Chen Ling , Peng Xu , Huang Yun , Li Lin , Li Xiao Xi
Published: March 2009

Porous ceramic materials usually require an optimal porosity and pore-size distribution to maximize the yield of the required function. In the starch consolidation forming for porous ceramic materials, the porosity and pore size distribution are corresponding closely to the particle size and swelling property of starch. In order to control the porosity and pore size distribution of the porous alumina ceramics, different modified starches with different amounts were added to the alumina slurry with a 58 vol% alumina solid volume loading. The effects of different modified starches and their content on the rheological behavior of the alumina slurry and the porosity, pore size distribution, compressive strength and microstructure of the sintered body were investigated. The results indicated that alumina/starch composite slurry still maintain stable and plastic in suitable condition of slurry preparation. After drying and sintering, materials with ultimate porosities between 22.7 and 68.7% were obtained. The pore of the resulting materials distributed uniformly and the average size was varied from 10 to 40μm. It concluded that the average size was controlled by the modified starch type, amount and the degree of modification. When the amount of the modified starches was reached to 60 vol% the porosities of the sintered samples were varied from 63.5 to 68.7% with different modified starch type and their bending strength varied within the range of 24-32 MPa.
Study on Alumina Ceramics for Dechlorinating Reactor Lining
Authors: Long Shi Gang , Cao Feng , Sun Liu Heng , Meng Qing Min
Published: March 2009

Al2O3 ceramics samples were prepared by changing the ingredient and sintering conditions.
The resistance experiment of the Al2O3 ceramics to hydrochloride corrosion and thermal shock were
carried out, and then identified by means of scanning electron microscopy and energy dispersive spectral
analysis. The results indicated the optimal Al2O3 and sintering condition for the dechlorinating reactor.
Low Temperature Sintered CaTiSiO5-CaTiO3 Dielectric Ceramics Doped by 2ZnO-B2O3
Authors: Chen Qiao , Lin Xu Ping , Deng Chang Sheng , Yue Zhen Xing
Published: March 2009

The dielectric ceramics of CaTiSiO5-CaTiO3 with ZnO and B2O3 as additives were sintered at 950°C. Of the ceramics with a small quantity of 2ZnO-B2O3 as the additive, the density is nearly the same as the one reported, εr= 83 ~ 99, tgδ < 7×10-4, αε= (-100~+100) ppm/°C. The crystal phases and microstructures are analyzed by X-ray diffraction and scanning electron microscope. It is found that the sintered ceramics is of biphase, comprising monoclinic CaTiSiO5 and orthorhombic CaTiO3, and the grains are mostly the small circular ones, having diameters of 1~29m. By adjusting the composing of the ceramic, a high frequency dielectric ceramic CaTiSiO5-CaTiO3, of which αε= (-50~+50) ppm/°C was attained.
Microstructure and Mechanical Properties of Mullite Composites via Pressure Molding and by Oxidation of an Al-Si Alloy Powder
Authors: Li Shun , Liu Jia Chen , Li Zhong Qiu , Fan Wei , Zhang Peng Yu
Published: March 2009

A novel technique to synthesize mullite by the oxidation of Al-Si alloy powder was used for the
manufacture of mullite via pressure molding. The mixed powder was consisted of powders of Al-Si alloy,
Al2O3 and SiO2 and additives or powders of Al-Si alloy, Al2O3, SiO2 and ZrO2 and additives. Those mixed
powders were milled in nonaqueous slurry in order to prevent the oxidation of Al-Si alloy. Then the green
bodies were pressureless sintered in air at ≥1380 °C. The Oxidation caused an internal volume expansion,
resulting in reducing shrinkage stresses during reaction- bonding of composites, which minimized the
sensitivity to crack formation. Comparing with non zirconia reinforced mullite composites, the effect of
the microstructure and mechanical properties of mullite composites were studied.
Microstructure and Mechanical Properties of C/SiC Composites Prepared at Low Temperatures
Authors: Zhou Chang Cheng , Zhang Chang Rui , Hu Hai Feng , Zhang Yu Di , Wang Zhi Yi
Published: March 2009

2D-C/SiC composites with high performance were prepared at temperatures as low as 900 °C. The flexural strength of the composites reached 329.61MPa, the same level as the composites prepared at 1200°C, and shear strength and fracture toughness were 32.14MPa and 14.65MPa·m1/2, respectively. The microstructure and mechanical properties of the composites after heat-treatment at 1600°C were also investigated to determine the potential applications at high temperature.
Preparation of In Situ Synthesized SiC Particles Reinforced Highly Porous Si3N4 Ceramics by Gel-Casting
Authors: Zeng Hong , Wang Hong Jie , Yu Juan Li , Lin Dan Bo , Qiao Guan Jun , Gao Ji Qiang
Published: March 2009

In this paper, highly porous Si3N4 ceramics with high strength, homogeneous microstructure
were fabricated by introducing a proper amount of nanometer carbon in the Si3N4 slurry by gel-casting.
Scanning electron microscopy, X-ray diffraction, Archimedes water-displacement method and
three-point bending tests were employed to analyze the microstructures and mechanical properties of the
sintered bodies. It was shown by the XRD analysis that SiC particles were formed in the sintered bodies.
The pillar β- Si3N4 morphology, homogeneous microstructure and the SiC particles as a reinforcement
phase are the contributing factors for high porosity and good mechanical behavior.
Fabrication of High-Content Ti3AlC2 Powders by Mechanical Alloying
Authors: Yang Chen , Jin Song Zhe , Xu Cheng Yu , Jia Shu Sheng
Published: March 2009

In the present study, high-content Ti3AlC2 ceramic powders were fabricated by mechanical
alloying (MA) using the Ti, Al and C as the starting materials. And the effect of Al content on the
formation of Ti3AlC2 was investigated. The results showed that the large-sized granules were obtained to
coexist with the powders after ball milling of 3Ti/Al/2C powder mixtures for 3 h. Ti3AlC2 in the
synthesized powders is the main phase based on the XRD analysis. For the composition of 3Ti/1.1Al/2C,
high-content Ti3AlC2 powders (87.6 wt.%) have been obtained after milling for 3h. Excessive Al,
however, would reduce the content of Ti3AlC2 in the products.
Synthesis and Characterization of CrXN Nano-Multilayer Coatings
Authors: Li H.Q. , Li X.Y. , Sun Hai Lin , Teer Dennis , Dong Han Shan
Published: March 2009

Three types of nano-multilayer coatings, CrSiN, CrAlN and CrMoN, with different Si, Al
and Mo contents were deposited on M42 substrates using a closed field unbalanced magnetron sputter
ion plating (CFUMSIP) technique. Systematic characterization on the chemical composition,
microstructure, hardness and wear properties of these multilayer coatings has been investigated using
GDOES, low angle XRD, SEM, TEM, nanoindentation and wear tests. Experimental results revealed
that all these three types of Cr, XN ternary coatings (X=Al, Si and Mo) are nano-multilayer structured.
The CrAlN multilayer coatings showed the highest hardness and oxidation resistance among these
three multilayer coatings. The CrMoN multilayer coatings exhibited the lowest friction coefficient
although no appreciable improvements in wear resistance were observed as compared with the
optimized CrN coatings.
Study on Interfacial Bonding Strength of TiN Films Prepared by Magnetron Sputtering at Low Temperature
Authors: Bai X.Q. , Li J.
Published: March 2009

Reactive magnetron sputtering technique was used to gain titanium nitride (TiN) films on
W18Cr4V high-speed steel and GCr15 bearing steel substrates at low temperature. The Surface
chemical composition of the films was analyzed using energy dispersive X-ray spectroscopy (EDXS)
and the surface morphology was examined using atomic force microscopy (AFM). Moreover, a series
of experiments have been conducted to study the relationship between interfacial bonding strength
and some major technological parameters, that is, substrate surface roughness, negative bias voltage,
intermediate transition layer, substrate hardness, and ion etching before deposition. The experimental
results have indicated that the TiN film with typical ratio of chemical metric can be deposited on
substrates using reactive magnetron sputtering technique below 140°C. The AFM image has showed
that the TiN film using magnetron sputtering technique was composed of densely distributed
nano-grains with uniform structure. Its surface was flat and smooth. The indentation testing results
have showed that the increase of surface roughness and substrate hardness improves the bonding
strength of TiN / substrate significantly. Furthermore, the bonding strength of TiN / substrate can also
be improved through the following methods: (1) choosing a proper intermediate transition layer; (2)
adopting ion etching before deposition and (3) increasing negative bias voltage before deposition.
Effects of Substrate Bias Voltage on the Microstructure of Cr-Al-N Coatings
Authors: Zhu Ming , Duo Shu Wang , Li Tian Peng , Li Mei Shuan , Zhou Yan Chun
Published: March 2009

Cr-Al-N coatings with the thickness of about 2 μm have been prepared by a reactive
magnetron sputtering method. The effects of substrate negative bias voltage (VB) on the
microstructure and critical failure load have been investigated as the VB varied from 0 to –150 V.
With VB increasing, grain size, lattice parameter and microstrain increase. (111) preferred orientation
dominates in the coatings deposited under 0 and –50 V, while a (200) preferred orientation developed
when VB further raised. The reasons for these variation caused by VB are discussed.
The Microstructure and Properties of CrNx Films Synthesized by Unbalanced Magnetron Sputtering
Authors: Wu Yan Ping , Leng Yong Xiang , Hong Sun , Zhu Sheng Fa , Huang Nan , Bai Bin , Zhang Peng Cheng
Published: March 2009

CrNx film was widely used in mechanical engineering field because of its excellent
anti-wear and corrosion resistance properties. While most of research was focused on mechanical
properties, little attention had been paid to the corrosion resistance and residual stress of CrNx film .
In this paper, CrNx films were deposited on silicon wafer (100) and iron substrate by unbalanced
magnetron sputtering system (UBMS) at different N2 flow. Then the structure, thickness, residual
stress, micro-hardness, wear-resistance and anti-corrosion properties of CrNx films were investigated.
The results showed that the phase composition of CrNx films transformed from Cr, single phase Cr2N,
Cr2N and CrN coexist to single CrN with the N2 flow rate increasing. The CrNx films composed with
Cr2N phase, which deposited at 6 sccm N2 flow, had the highest microhardness and had higher
compressive residual stress. Whereas the CrNx films with CrN and Cr2N phase coexist had the best
wear and corrosion resistance.
Performance Study of Erosion Wear of Nanostructured WC-12Co Coatings Sprayed by HVOF
Authors: Ding Z.X. , Wang Q. , Liu Zheng Lin
Published: March 2009

In the paper, nanostructured, multimodal and conventional WC-12Co cermet coatings
were sprayed by HVOF and the properties and structures of the coatings such as microhardness,
microstructure, phase composition were compared. Finally sand solid and slurry erosion wear tests
were carried out and their wear failure mechanisms were explored by XRD and SEM analysis.
Research results show that microstructures of nanostructured and multimodal WC-12Co coatings
prepared by HVOF are dense with little porosity, and their microhardness values are obviously
higher than conventional WC-12Co coating. As well, it was found that nanostructured and
multimodal WC-12Co coatings exhibited better sand solid and slurry erosion wear resistance in
comparison with conventional coating and nanostructured WC-12Co coatings possessed the best
sand solid erosion resistance properties at large impact angles and slurry erosion wear resistance.
Testing results also show that although decarburization of WC occurred during spraying multimodal
and nanostructured WC-12Co powders, the decarburization of WC for the nanostructured powder
was more severe.
Microstructural Features of EB-PVD Thermal Barrier Coatings Irradiated by High-Intensity Pulsed Ion Beam
Authors: Liu C. , Han X.G. , Zhu X.P. , Lei M.K.
Published: March 2009

Thermal barrier coatings (TBCs) fabricated by electron-beam physical-vapor deposition
(EB-PVD) were irradiated by high-intensity pulsed ion beam (HIPIB) at an ion current density of 100
A/cm2 with a shot number of 1-10. Microstructural features of the irradiated EB-PVD TBCs were
characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM) and
transmission electron microscope (TEM), respectively. All the HIPIB-irradiated EB-PVD TBC
surfaces present smooth and densified features. The originated intercolumnar channels growing out to
the top-coat surface and nanometer-scale gaps inside each single column were sealed after the
remelting of TBC surface induced by HIPIB, resulting in formation of a continuous remelted layer
about 1-2 μm in thickness. The dense remelted layer can work as a barrier against the heat-flow and
corrosive gases, and gives the possibility of improving thermal conductivity and oxidation resistance
of the HIPIB irradiated EB-PVD TBC.
Fabrication of SiC Particulates Reinforced MoSi2 Composite Coating by Laser Cladding
Authors: Yang Sen , Wang Ming Run , Gong Tao , Liu Wen Jin
Published: March 2009

In order to improve wear resistance of carbon steel, laser cladding experiments were
carried out using a 3kW continuous wave CO2 laser. The diameter of the laser beam was 3-5mm,
the scanning velocity was 3-10mm/s, and the laser output power was 1.0-1.3kW. The experimental
results showed that MoSi2/SiCP composites coating could be in-situ synthesized from mixture
powders of molybdenum, silicon and SiC by laser cladding. A good metallurgical bond between the
coating and the substrate could be achieved. The microstructures of the coating were mainly
composed of MoSi2, SiC and FeSiMo phases. The average microhardness of the coating was about
HV0.21300, about 6.0 times larger than that of steel substrate.
Technical Study of Exhaust Valve Overlaying Based on Micro-Plasma Arc Welding
Authors: Xiang Yong Hua , Xu Bin Shi , Lv Yao Hui , Xia D.
Published: March 2009

The micro-plasma arc welding technology（MPAW） was used to remanufacture the
exhaust valve of W615 engine. The ST6 Co alloy powder was selected as overlaying material, the
processing parameters of overlaying was optimized considering the geometry demand of deposited
layer, and the current downslope method was adopted to weaken the arc crater. The microstructure
characteristics and the micro-hardness of the weld were investigated, no defects were found in the
deposited layer or at the interface, and the heat-affected zone among joint was not evident. The
maximum hardness situated at the top layer being 657.8HV, with a slight decrease towards the
bottom layer and fusion zone.
Micro-Damage Evolution and Residual Stress in Thermally Grown Oxides of Detonation Gun Sprayed Thermal Barrier Coatings
Authors: Chen Z.X. , Zhu Shijie , Wang Z.G. , Yuan F.H.
Published: March 2009

Thermal barrier coatings (TBCs) were prepared by the recently-developed detonation gun
spray process. The oxide scale formation and micro-damage evolution of these coatings during
oxidation in air at 1100 °C were investigated. It was found that duplex oxide scales, the upper oxide
mixture scale and α-Al2O3 subscale, form at the interface between bond coat (BC) and top coat (TC)
during the oxidation. Microcracks usually nucleate within the porous oxide mixture layer. With the
increase of oxidation time, some microcracks coalesce to form a long crack. Residual stress in the
thermally grown oxides (TGO) was measured using photo-stimulated luminescence spectroscopy. It
was found that compressive residual stress exhibits a fast increase at the beginning of oxidation up to
maximum value for about 10h. Then, the compressive stress begins to decline up to 100h. Local stress
distribution showed that the micro-damage in the TGO causes a remarkable decrease in the magnitude
of compressive residual stress.
Microstructure and Performance Analysis of Cr3C2-25%NiCr Coating Prepared by Plasma Spraying Process
Authors: Wang Can Ming , Sun Hong Fei , Song Qiang
Published: March 2009

Cr3C2-NiCr compound coating was acquired on 20 steel substrate by plasma spraying
process. The microstructure of the coating is dense with low porosity. Carbide lamellartiy inlays
into the nickel-base solid solution in the coating. Main phases of the coating are Cr3C2, Cr23C6,
Cr7C3 and nickel-base solid solution, etc. Average microhardness of the coating is about
HV0.1756.9. Microhardness of some ceramic phases in the coating is as high as HV0.11113, which
helps to the improving of wear resistance of the coating. The wear-resisting property of the coating
is good under grain-abrasion condition and excellent under lubricated wear condition.
Structure and Wear Resistance at Elevated Temperature of Auto Brush-Plating n-Al2O3/Ni Composite Coatings
Authors: Zhang Bin , Xu Bin Shi , Dong Shi Yun , Wu Bin
Published: March 2009

Nanoparticle reinforced nickel matrix composite coating, n-Al2O3/Ni, was prepared by
manual brush-plating and auto brush-plating technologies. For the auto-coating, the surface was
smooth and made up of large quantity spheroid grain. The observed auto-coating’s structure was
dense. Compared with the auto-coating, the manual-coating’s surface was coarser, the grains that
form the surface were not spheroid but anomalistic and similar to cauliflower. The structure of
manual-coating was sparser than the auto-coating’s. And the test found that the auto-coating’s
micro-hardness improves 8% than the manual-coating’s. Results of the friction wear testing at
elevated temperature showed that the wear resistance of auto-coating decreases while the temperature
goes higher. It was concluded that during the process of auto-coating, with the help of computer, the
speed, pressure and flow brush liquid was stable. While during the manual process the parameters
were not controlled so that the quality of the coating was influenced. The other advantage of the
auto-coating was set worker free from the front line, decrease harm to worker, provide comfortable
working condition, and keep the coating’s quality on a high level, can be adapted to large-scale
popularization and application.
Effect of Plasma Sprayed Coatings on Stress Corrosion Cracking of 08Cr2AlMo Steel in Saturated H2S Solution
Authors: Zhang Yao Feng , Gu Bo Qin , Ding Yi
Published: March 2009

Three kinds of coating materials, namely Al2O3, Al2O3(87%)-TiO2(13%), and Cr2O3(92%)
-TiO2(3%)-SiO2(5%), were plasma sprayed on specimens of 08Cr2AlMo steel. The corrosion
performance of the specimens was determined by potentiodynamic polarization test, slow strain rate
tensile (SSRT), and scanning electron microscope (SEM). The test results indicate that the plasma
sprayed coatings do not show passivation in saturated H2S solution, but they have higher corrosion
resistance than the bare 08Cr2AlMo steel. Furthermore, these coatings reduce SCC susceptibility of
the steel in saturated H2S solution. The specimens treated by plasma spray have longer fracture time
and larger area reduction. The SCC resistance depends largely on coating porosity, coating type and
the bond strength between the coating and the substrate. Among the three coatings, the
Cr2O3(92%)-TiO2(3%)- SiO2(5%) coating exhibits the lowest SCC susceptibility.
Corrosion Behavior of TiO2 Coating on Magnesium Alloy AM60 in Hank’s Solution
Authors: Zeng Rong Chang , Dietzel Wolfgang , Chen Jun , Huang Wei Jiu , Wang Jun
Published: March 2009

As magnesium is an essential element for the human body, magnesium alloys are
expected to be promising implant materials despite their lower corrosion resistance. The most
potential advantages of magnesium lie on both excellent biocompatibility and good mechanical
properties. A TiO2 coating had been successfully deposited on the surface of AM60 samples by
using a thermal spray technique and was then sealed with sodium silicate. The corrosion
behavior was investigated by using the potentiodynamic electrochemical technique. The
experimental results demonstrated that the TiO2 coating had a porous ceramic structure. The
thickness and micro hardness of the layer reached 40 μm and 886 HV, respectively. After
additional sealing with sodium silicate, TiO2 coating on magnesium alloy improved corrosion
resistance in Hank’s solution.
In situ Photoemission Study on Initial Growth of Er2O3 Films on Si(001)
Authors: Zhu Y.Y. , Fang Z.B. , Chen Shu , Liao C. , Jiang Z.M.
Published: March 2009

Synchrotron radiation photoemission spectroscopy was used to study the initial growth of
Er2O3 films on Si in O2 pressures of 7×10-6 Torr. An interface layer was observed at the initial growth
of Er2O3 film on Si, which is supposed to be attributed to the effect of the Er atom catalytic oxidation
effect. With the film growth process continued, oxygen deficient Er oxide will capture oxygen from
the interface layer which is formed inevitably at the initial growth of Er2O3 film and thus reduce and
even remove the interface layer if the condition of O2 pressure is a little insufficient at a high substrate
temperature.
Research on the Surface Treatment of Carbon Fibers Used in Fabrication of MMCs Wire
Authors: Wang Ling , Zhao Hao Feng
Published: March 2009

MMCs wire can be produced by infiltration of molten metal into carbon fiber bundles. To
protect the fibers from damage, the desized fibers must be pretreated before fabrication into wire.
This paper deals with the formation of SiO2 coating on the carbon fibers using plasma chemical
method and compares the coating produced by plasma method with the one by sol-gel method. The
SiO2 coating produced by the sol-gel method on the carbon fibers is very rough. It is also
discovered that the quality of the SiO2 coating is controlled by the power of plasma equipment and
the flow rate of plasma gases. As the power of the plasma equipment and the flow rate of plasma
gases increased, the coating surface became smoother.
Fabrication, Surface Modification and Analysis of Biocompatibility of Biologic Chitosan Scaffold
Authors: Song Ke Dong , Wen Peng Fei , Liu Tian Qing , Jiang Li Li , Mei Guan Yu
Published: March 2009

In this study, the surface modification and biocompatibility of the biologic chitosan
scaffold were investigated. The chitosan scaffold with excellent reticular structure was attained after
being purified, emulsionized, cross-linked, molded and freeze-dried step by step by using the native
materials, coming from such as lobster shell, crab shell etc.. After that, its surface modification was
operated with film coating by using gelatin. Then the bone marrow mesenchymal stem cells (BMSCs)
derived from New Zealand rabbits were used as the seed cells and were inoculated onto the modified
biologic chitosan scaffolds at 3×105 cells/ml to investigate the biocompatibility and bone conductive
efficiency of this kind of scaffold in static culture for one week. As a control, the cell suspensions with
same densities were inoculated onto the chitosan scaffold without being treated. During the whole
culture process, the cellular adherence and expansion were observed under inverted microscope.
After culture, the biological properties of the fabricated cell-scaffold tissues were detected by
scanning electron microscope (SEM) and HO/PI fluorescent double staining. The results showed that
the biologic chitosan scaffold treated with gelatin or rat-tail collagen promoted a higher adhesion and
proliferation of BMSCs in comparison to the untreated samples. Besides, the BMSCs within the
treated scaffold were more regular and well-distributed than those in untreated one. It is concluded
that this kind of surface modification can be used to change the physicochemical properties of
chitosan scaffold. The improved biologic chitosan scaffold is suitable to be an ideal biomedical
scaffold for tissue engineering.