bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of AZO Thin Films by Sol-Gel Process: The Influences of Precursors and Dopants
Authors: Tsai M.T. , Chang H.C. , Tsai P.J.
Published: March 2009

Transparent ZnO and aluminum-doped zinc oxide (AZO) thin films were prepared via the
sol-gel process on glass substrates using an alcoholic non-polyol route and spin-coater technique for film
deposition. Zinc acetate, zinc chloride, and aluminum salt used as cations source. All the undoped and
doped xerogel films were amorphous and converted into zincite structure after firing at 200 oC,
irrespective of precursor types and dopant amounts. However, the evolution of morphology,
microstructure, and texture of the gel films were strongly depended on the precursors and dopants. The
films derived from zinc chloride showed strongly preferential (002) orientation, while acetate-derived
films exhibited random orientation. On firing at 500 oC, the visible transmittances of films were 50~92%,
depending on the kinds of precursors and dopant contents.
Preparation of Sm2O3 Optical Thin Film by Hydrothermal Process
Authors: Huang Yan , Huang Jian Feng , Cao Li Yun , Wu Jian Peng , Chen Dong Xu
Published: March 2009

Sm2O3 optical thin films were prepared by hydrothermal method using samarium dichloride as source material. The influence of preparation temperature on the crystallinity, morphology and optical properties of Sm2O3 thin film were investigated. The as-fabricated thin films were characterized by X-ray diffraction, atomic force microscopy and spectrophotometer. Results show that the prepared thin film is Sm2O3 crystallites thin film with compact and uniform surface microstructures. Transmittance curve displays that the Sm2O3 crystallites thin films are transparent to visible and infrared light; and possess excellent absorbency of UV light. With the increase of deposition temperature, the crystallinity and optical properties of the prepared Sm2O3 thin film are improved. With the increase of hydrothermal temperature from 170 °C to 185 °C, the bandgap of the thin film increase from 2.88 eV to 2.95 eV.
Manganite-Based Heterojunction Position-Sensitive Detectors
Authors: Zhao Kun , Lu Hui Bin , He Meng
Published: March 2009

Position-sensitive photodetectors, a useful class of sensor with a wide range of applications in automatization and measuring techniques, on the basis of a La0.7Sr0.3MnO3/Si heterojunction have been developed. Thin p-La0.7Sr0.3MnO3 films were grown on n-Si substrates by laser molecular beam epitaxy. The large lateral photovoltaic effect has been observed in response to excitation by ultraviolet laser spot irradiation. The position characteristics are symmetric to the zero and linear between the contacts. The devices work well under unbiased conditions and so are simple to configure for practical applications.
VUV Spectral Properties of MBPO7 Co-Doped with Tm3+ ,Gd3+
Authors: Li Xin , He Da Wei , Lu Peng Zhi , Wang Yong Sheng
Published: March 2009

A series of phosphor of MBPO7:Tm3+, and MBPO7:Tm3+, Gd3+ (M= Mg, Sr, Ca) were prepared
and studied. The XRD data showed Tm3+, Gd3+ didn’t affects the lattice parameters. Excitation spectra
exhibited high absorption in vacuum ultraviolet (VUV) region. There existed strong emission peaking at
453nm and 363nm correspond to the 1D2
→3HJ
(J=4, 6) emission transition of Tm 3+ when excited under
VUV. With the changes of cation in the samples, the excitation spectra changed greatly, and lead a great
change in its emission spectra. The crystal lattice parameters affect the ratio of intensity of the peak at
454nm and 312nm.
Preparation and Luminescent Properties of SrAl2O4:Eu2+,Dy3+
Authors: Xu Xiao , Cao Li Mei , Jiang Dan Yu , Li Qiang
Published: March 2009

The luminescent properties of SrAl2O4 based materials were studied systematically, which
emit long persisting phosphorescence with high brightness and show greater chemical stability than the
traditional ZnS:Cu,Co phosphor. In order to obtain the better dispersed powders, SrAl2O4:Eu2+, Dy3+ was
synthesized by a dipping process. The as-received samples are yellow-green in color and display better
dispersion than those synthesized by the co-deposition method. The optimized conditions of this dipping
process were explored. The luminescent properties and the crystal structure were studied in detail.
Synthesis of Ultrafine MgAl2O4 Powders by Nitrate-Citrate Sol-Gel Combustion Process
Authors: Chen Long , Zhang Qi , Chen Wen Ping , Li Yao Gang , Chen Yan Mo , Zhu Mei Fang
Published: March 2009

Ultrafine MgAl2O4 powders were synthesized by a nitrate-citrate sol-gel combustion process using Al(NO3)3·9H2O, Mg(NO3)2·6H2O and C6H8O7·H2O as initial materials. The result of X-ray diffraction (XRD) analysis indicated that single-phase MgAl2O4 powder could be obtained at 850 oC, which is much lower than that needed in solid-state reactions. Transmission electron microscopy image showed that the as-prepared powder was in the nano scale and little agglomerate exited. It is concluded that this process need shorter time, lower temperature, and simple equipments.
Highly doped Mn:MgAl2O4 Transparent Ceramics
Authors: Wang Xue Jun , Lu Tie Cheng , Sun Yue Feng
Published: March 2009

To determine the optimal doping concentration, a series of Mn:MgAl2O4 were successfully prepared through vacuum-sintering with the highest doping concentration up to 35%. Samples with a low doping concentration exhibit a light green color. When the doping concentration increases, its color becomes deeper and deeper and when the doping concentration reaches 14%, their colors become brown and deeper brown when their concentrations further increase. The crystal phases of the samples were manifested by XRD measurements and their photoluminescence properties were studied. Combined with phase analysis, optimal doping concentration of transparent ceramics has been determined. In addition, the mechanism for fluorescence of Mn:MgAl2O4 transparent ceramics has also been discussed.
Microstructure and Electrical Properties of BaTiO3-Based PTC Ceramics Prepared from Nanopowders
Authors: Liu Huan , Gong Shu Ping , Zhou Dong Xiang , Cheng Chun Fang , Zheng Zhi Ping , Hu Yun Xiang
Published: March 2009

Dense PTC ceramics were prepared with BaTiO3 nanopowders synthesized by hydrothermal method. BaCO3 and Ti(OC4H9)4 were used as barium and titanium sources, and Y(NO)3·6H2O as the donor dopant respectively. The average grain size of the powders obtained after hydrothermal treatment at 160°C for 9h was about 30nm with cubic structure. Mn(NO3)2 was introduced to the as-prepared nanopowders in order to improve the PTC effect. After sintered at 1280°C, the PTC ceramic samples exhibited sufficient resistance jump ratio(1.086×103) around Curie temperature, the density of which was 5.81g/cm3(96.5% of the theoretical density).
Modification of Electrical Properties of T-ZnO Whisker by Doping Fe
Authors: Huang Xiao Zhong , Liu Han Dong , Xing Xin
Published: March 2009

By means of high temperature solid-state reaction process, tetra-pod ZnO whisker (T-ZnOw)
was doped with Fe(NO3)3. The doping induced the lattice distortion of the T-ZnOw, and improved its
electrical properties significantly. After doping, the volume resistivity of the T-ZnOw decreased from
1010 &·cm to 103 &·cm, and its dielectric constant changed correspondingly.
Low Temperature Hydrothermal Synthesis and Sintering of Ba0.6Sr0.4TiO3
Authors: Fu Yun Fei , Zhang Pei Feng , Fan Hui Qing , Chen Xiu Li
Published: March 2009

Ba0.6Sr0.4TiO3 nanopowders (~ 80 nm in size) were prepared by low temperature hydrothermal process. The process and synthesis mechanism were discussed in detail. Furthermore, the powders were pressed into disc-shaped pellets and sintered at different temperatures. The frequency dependence of the dielectric constant and loss angle tangent of the sintered BST ceramics are measured from room temperature to 500°C and a diffuse dielectric anomaly by the dielectric relaxation was found.
Fabrication of Mn2O3 Nanowire with Ultra Fine Morphology via an Electrospinning Technology
Authors: Zhang Rui , Wu Hui , Lin Dan Dan , Pan Wei
Published: March 2009

Thin Mn2(NO3)2/PVA precursor nanowire was fabricated via electrospinning technology at a low temperature in this paper. After dried at 150°C for 10 hours and then sintered at 450°C for 2 hours, Mn2O3 nanowire was successfully obtained. The nanowire was characterized using X-ray diffraction and scanning electron microscopy. The results showed that the nanowire was composed of pure Mn2O3 phase. The nanowire exhibited smooth surface and continuous sharp with length of tens of micrometer. The diameter of Mn2O3 nanowire was measured and calculated through SEM, which showed most probable value of about 110 nm and 270 nm. The reason of the diameter separation was also discussed.
Effect of Annealing Temperature on the Microstructure of Barium Strontium Titanate Films
Authors: Liao Jia Xuan , Li En Qiu , Tian Zhong , Xu Jiang , Yang Hai Guang
Published: March 2009

Barium strontium titanate (Ba1−xSrxTiO3, BST) films have been prepared on Pt/Ti/SiO2/Si by
medium frequency (MF) magnetron sputtering, and subsequently in situ crystallized at 500-700°C. The
microstructures of the MF-BST films are studied. BST films prepared by radio frequency (RF) magnetron
sputtering and exhibited preferential (110) orientation, are compared. XRD shows that the MF-BST films
exhibit preferential (111) orientation and better crystallization than the RF-BST films at the same
annealing temperature. AFM displayed that the MF-BST films were smooth and compact. XPS analysis
exhibited that the MF-BST films revealed better surface and interface structural characteristics. Their
dielectric properties were also compared.
Preparation and Thermoelectric Properties of Al2O3-Doped ZnO Ceramics
Authors: Qu Xiu Rong , Jia De Chang
Published: March 2009

Al2O3-doped ZnO ceramics were prepared via chemical co-precipitation processing. Zinc
acetate, ammonia and Al2O3 powders are used as starting materials. Scanning electron microscopy (SEM)
observations reveal that the doping of Al2O3 has an obvious influence on the microstructure of ZnO
ceramics. Ordinary cold pressing and cold isostatic pressing (CIP) were used to prepare green compacts.
The thermal conductivity and electrical conductivity of the Al2O3-doped ZnO ceramics were measured as
a function of the testing temperature (0-900oC). Doping of Al2O3 is beneficial to improve thermoelectric
(TE) properties of ZnO ceramics. CIP can also improve TE properties of Al2O3-doped ZnO ceramics.
Cofiring Behavior of Ferroelectric Ferromagnetic Composites
Authors: Qi Xi Wei , Zhou Ji , Yue Zhen Xing , Li Ming Ya , Han Xiu Mei
Published: March 2009

Cofiring behavior of composites consisting of ferroelectric PMZNT and ferromagnetic NiCuZn
ferrite was investigated via X-ray diffractometer (XRD), thermomechanical analysis (TMA) and scanning
electron microscopy (SEM). Mismatch of sintered camber consisting of two layered structure of
ferroelectric PMZNT and NiCuZn ferrite was observed. Mismatched sintering behavior was modified by
adopting PMZNT and NiCuZn powders to form composite materials. The temperature of appearance
pyrochlore phase in prepared composite materials is lower than that of sintering pure PMZNT material.
The grain size of PMZNT and NiCuZn in prepared composites is smaller than that of sintering pure
PMZNT and NiCuZn ferrite, respectively.
Complex Permeability Spectra of Co-Substituted Lithium Zinc Perminvar Ferrite
Authors: Zhao Hong Jie , Zhou Ji , Li Long Tu
Published: March 2009

The effect of Co-substitution on the complex permeability of LiZn ferrite was studied. The polycrystalline ferrite samples with a composition of ((Li0.5Fe0.5)0.8Zn0.2)1-xCoxFe2.05O4, where x varies from 0 to 0.08, were prepared by solid-reaction method. The sintered samples were annealed at 490oC for 96 h to produce perminvar effect. The complex permeability was measured in the frequency range from 1 MHz to 2 GHz. The Co-substitution can enhance the real part of complex permeability (μ’). The maximum μ’ appears when x=0.02. The Co-substituted LiZn samples, especially for x=0.02 and 0.04, present resonance-type magnetic spectra obviously. The μ’ of the sample for x=0.02 increases because the damping of domain wall movement decreases after the annealing treatment. The resonance character of the annealed sample becomes even more remarkable due to its domain wall stabilization.
Preparation and Magnetic Properties of Dense NiCuZn Ferrite by Spark Plasma Sintering
Authors: Qi Xi Wei , Zhou Ji , Yue Zhen Xing , Li Ming Ya , Han Xiu Mei
Published: March 2009

Dense NiCuZn ferrites consisting of fine grains were prepared by spark plasma sintering (SPS) at 750°C for 3 min under a uniaxial pressure of 15 MPa. The powders were densified to >95% of theoretical density by the SPS process, and the average grain size of the prepared NiCuZn ferrite was < 1 /m. The saturation magnetization of prepared specimens (without further annealing treatment) was approximate 50.54 emu/g, which was slightly smaller than that of 52.21 emu/g for specimens prepared by conventional sintering at 980°C for 4 h. Phase identifications indicated that prepared NiCuZn ferrite existed impurity phase (Cu2O), and Cu2O would gradually transform to CuO when annealing temperature increased.
Effect of Pre-Treatment on the Microstructure and Superconducting Properties of Bi-2223/Ag Tapes
Authors: Li Ming Ya , Han Zheng He
Published: March 2009

The effect of pre-treatment on the microstructure and critical current of (Bi,Pb)-2223/Ag tapes
has been investigated. Experimental results show that pre-treatment has important influences on the
formation and the grain size of the (Bi,Pb)-2223 phase as well as the performances of Bi-2223/Ag tapes.
During the pre-treatment process, the decomposition of the 3321 phase enhances the growth of
(Bi,Pb)-2212 grains, which promotes the formation of (Bi,Pb)-2223 phase because it followed the size
and orientation of the original (Bi,Pb)-2212 phase. As a result, the properties of Bi-2223/Ag tapes were
remarkably improved.
An Aqueous Photocrosslinkable Chitosan-PVA (Polyvinyl Alcohol) Binder for Tapecasting Alumina Substrates
Authors: Cheng Jun Hua , Wen Di Jiang
Published: March 2009

An aqueous photocrosslinkable binder system for tapecasting ceramic substrates was investigated
based on chitosan (CS) and polyvinyl alcohol (PVA) by adding UV photoinitiator 2-hydroxy-1-
[4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone (Darocur 2959). Alumina green sheets were prepared
by using the binder and exposed to UV irradiation. SEM, FT-IR, XRD and DSC verified that these
CS/PVA polymeric films or green sheets obtained using the binder were homogeneous, which indicated
that CS was compatible with PVA in the binder, polymeric films and green sheets. Blending CS and PVA
may created a semi-interpenetratin structure with good mechanical properties enough for handling and
machining, and the process may not have oxygen retarding effect in arcylamide system.
Experimental and Numerical Researches of Dynamic Failure of a High Strength Alumina/Boride Ceramic Composite
Authors: Zhang Jiang Tao , Liu Li Sheng , Zhai Peng Cheng , Zhang Qing Jie
Published: March 2009

The dynamic compressive behavior of Al2O3 (10% vol.) / TiB2 ceramic composite had been
tested by using a split Hopkinson pressure bar in this paper. The results show that the main failure modes
of the ceramic composite include crushed failure and split fracture along the loading direction. The
former is the typical compressive failure of brittle materials. The later is tensile failure along the flaws
produced during the composite manufacturing. The numerical simulation was also used to study the effect
of the diameter/length ratio of the samples on the experimental results. The effect of the deformation in
the bars’ ends, which contacted with the samples, was also studied in the numerical models.
Properties of In Situ Synthesized Alumina Ceramic Core Composites
Authors: Qin Ye Xia , Du Ai Bing , Zhang Rui , Pan Wei
Published: March 2009

A series of alumina-based ceramic cores were in situ prepared. Effect of kyanite on the
properties of ceramic core was discussed. The results indicated that the microstructure of the core is
characterized by the presence of unreacted Al2O3 particles having a polycrystalline composition
consisting essentially of in-situ synthesized 3Al2O3
.2SiO2 on the surface of the Al2O3 particles. The
ceramic cores of kyanite contents sintered at 1500oC for 3 h have almost no creep deformation.
Influence of Cosurfactant on the Structure and Properties of ZrO2 Nano-Powders Prepared in Microemulsion System
Authors: Geng Chun Lei , Zhu Zhen Feng , Yu Wei Jie
Published: March 2009

ZrO2 nano-powders were prepared by a microemulsion process with the water-in-oil system of water/cyclohexane/Triton X-100/hexyl alcohol. The influence of cosurfactant content and the heterogeneous distillation process on the structure and properties of the particles was studied. XRD analysis showed that the cosurfactant content has little influence on the crystal phase of ZrO2. With the increasing mass ratio of cosurfactant to surfactant from 0.3 to 0.5 and 0.7, the average size of ZrO2 powders increases from 23.3 to 25.2 and 27.5 nm. The heterogeneous distillation process can effectively inhibit the formation of hard agglomeration during evaporation and increase the specific surface areas of ZrO2 powders.
Wear Properties of Y-TZP Ceramics Dispersed with Second Phase Particles
Authors: Liang Xiao Ping , Xin Shao Bo , Wang Xiao Hui , Yang Zheng Fang
Published: March 2009

The wear properties of ADZ (alumina dispersed in Y-TZP) and MDZ (mullite dispersed in Y-TZP) were investigated by using a ring-on-block tribometer. The results showed that for Y-TZP ceramic, the addition of alumina phase (with 10-20% in mass fraction) leads to an improved wear resistance. With the increase of the normal load, the wear rates of ADZ ceramics increase. Under low and medium normal load (100N and 300N), the wear resistance is controlled by the hardness of ceramics, and under high normal load (500N) the fracture toughness is obviously contributed to the wear resistance of the ceramics. For MDZ ceramic, the wear resistance of 15MDZ (15wt% mullite dispersed in Y-TZP) is better than that of 20 MDZ (20wt% mullite) under the normal load from 100 N to 500 N. The mechanical properties of 15MDZ are worse than that of Y-TZP ceramic, but the wear resistance is enhanced due to the action of “needle roller bearing” of the fractured rod-like mullite particles.
Influence of Preparation Temperature on Performance of Ce1-xPrxO2 Ultrafine Powder Prepared by a Microemulsion Process
Authors: Yang Jun , Zhu Zhen Feng , Li Jing Ping
Published: March 2009

A W/O microemulsion system composed of OP-emolsifier / water / cyclohexane / 1-Pentanol was adopted to prepare ultrafine Ce1-xPrxO2 powder via the reaction between the precipitants of cerium and praseodymium salt solved in the nano reactors. The influence of the annealing conditions on the preparation of Ce1-xPrxO2 powder was investigated. It was shown that, with the increase of calcination temperature from 400 °C to 800 °C, the average crystallite size of the particles increases from 9.5 nm to 25.8 nm. FE-SEM images showed that shape of the particles is layered and sheet-like.
Preparation and Characterization of SiO2 Nanoparticles by Microemulsion Method
Authors: Yu Wei Jie , Zhu Zhen Feng , Geng Chun Lei
Published: March 2009

The stable region of microemulsion of Triton X-100/hexanol/cyclohexane/ water water-in-oil
(W/O) system was investigated by using distilled water as aqueous phase. SiO2 nanopowders were
prepared by hydrolysis of tetraethoxysilane (TEOS) in the designed reverse microemulsion. The prepared
samples were characterized by XRD and TEM. The results showed that the size of particles is within a
range of 40~50nm and the aggregation is not evident after heat treatment. The size of particle is minimal
and the dispersal is optimal when the ammonia content is 11% in volume.
Preparation and Characterization of (1-x)BiScO3-xPbTiO3 Ceramics by Two-Step Sintering
Authors: Zou Ting Ting , Wang Xiao Hui , Li Long Tu
Published: March 2009

High-performance fine-grain (1-x)BiScO3-xPbTiO3 ceramics were prepared by two-step
sintering method. Influences of sintering temperature, holding time, and composition on the
microstructure and properties were discussed. The BSPT ceramics obtained via two-step sintering
reaches density higher than 95% at a low temperature of 800°C without any sintering aid, and the grain
size of the ceramics is also effectively controlled. Excellent piezoelectric properties between the
composition of x=0.63 and x=0.64 reveals a probable MPB in this range, suggesting a potential approach
to pursue high performance BSPT ceramics.
Effect of Heat Treatment on the Microstructure of TiO2 Nanofibers Prepared by Refluxing in Basic Solution
Authors: Zhang Shi Ying , Xiao Fan Ping , Wu Luo Yi , Li Cheng Yong , Chen Zhen Hua
Published: March 2009

Using tetrabutyltitanate as titanium source, amorphous TiO2 powder was firstly prepared by a
sol–miniemulsion–gel method. Prepared powder was refluxed in basic solution and then calcined at
different temperatures to synthesize titania nanofibers. The prepared samples were characterized by
XRD, TG–DSC, FT–IR and TEM. The results show that when the heat–treatment temperature increases,
crystallization of the titania nanofibers occurs with two Ti–OH bonds dehydrate, meanwhile morphology
of the fibers is gradually obvious and ratio of length to diameter decreases. When the temperature was
raised above 550 °C, titania nanofibers were sintered.
Catalyst-Free Synthesis of Mullite Nanosticks
Authors: Zhao Fu Jun , Han Lin Hai , Liang Long
Published: March 2009

The nonstoichiometric Al-rich single crystal mullite nanosticks were prepared by sol-gel method without any catalysts. The nanosticks are straight and uniform with a width of 300-350nm and length of 3-5m. The nanosticks’ growth direction is along[210] . Detailed structural characterizations suggested that the growth of this novel nonstoichiometric structure was induced by the self-catalyzed process.
A Novel SiC Precursor with High Ceramic Yield: Antimony-Substituted Polysilane (APS)
Authors: Liu Lin , Xing Xin , Li Xiao Dong
Published: March 2009

A novel SiC precursor antimony-substituted polymethylsilane (APS) is present in this paper. First, pre-APS was synthesized from polymethylsilane (PMS) and SbCl3 at room temperature. Pre-APS was a liquid mixture and could be used in PIP process without solvent. After the elemination of HCl and the crosslinking of pre-APS, the novel precursor APS with the ceramic yield 91% was prepared.
Synthesis of Silicon Carbide Platelets by Double-Heating Technique
Authors: Meng Yong Qiang , Dai Chang Hong , Song Zu Wei
Published: March 2009

A new method for producing silicon carbide platelets with low cost and high yield was
introduced. The silicon carbide platelets were synthesized by double-heating technique with carbon black
and SiO2 powder as raw materials without using any catalysts. The starting mixtures were heated at a
temperature in the range of 1800-2000°C for the duration of about 2-4h to produce substantially
completely unagglomerated silicon carbide platelets with the thickness of 5-15μm and the average
diameter of 50-150μm. Compared to the conventional heating, double-heating technique has different
heating mechanism and has advantages of less investment for equipment, easy to manufacture and
convenient to operate. Furthermore, it is very suitable for realizing the scaled production because of the
lower synthesizing temperature, shorter reaction time and greater output.
Synthesis of Silicon Carbide Whiskers in Electric Field Furnace
Authors: Dai Chang Hong , Song Zu Wei , Zhao Ru
Published: March 2009

A new heating apparatus for synthesizing SiC whiskers was introduced. SiC whiskers were
synthesized in electric field furnace with carbon black and SiO2 powders as raw materials and some
influencing factors were discussed. SiC whiskers with diameter of 0.1-0.4μm, length of 5-70μm and
average purity of 99.6% were acquired at lower temperatures of 1200-1400°C for a shorter holding time
of 2-4h. The results showed that the high voltage field has great catalysis action on synthetic of SiC
whiskers by reducing activation energy and enhancing reaction speed.
Synthesizing Silicon Nitride Whiskers by Solvothermal and Carbothermal Methods
Authors: Tan Guo Qiang , Miao Hong Yan , Ren Hui Jun , Yu Zhi Wei , Li Jia , Li Hui Qin
Published: March 2009

Xerogel was prepared by the sol-gel method using ethyl ester orthosilicate, alcohol, carbamide
and glucose with various contents as raw materials. The precursor powders were obtained after xerogel
was solvothermally treated at 220oC for 2.5 h. IR analyses showed that the Si-O-Si and Si-O-NH2 bond
are obtained in the precursors. XRD analyses indicated that the powders prepared by the solvothermal
method are amorphous. Si3N4 powders are produced by heat-treating the precursors at 1400 oC in N2. It
was proved that the synthesized powders are α–Si3N4 whiskers. With the increase of the glucose contents
and the heat-treating temperature, the crystallization of Si3N4 is obviously improved.
Preparation of Si3N4 Ceramics by Aligning α-Si3N4 Whiskers
Authors: Bi Yu Hui , Li Jun , Chen Fei , Zhang Dong Ming , Shen Qiang , Zhang Lian Meng
Published: March 2009

In this paper, silicon nitride (Si3N4) ceramics by aligning α-Si3N4 whiskers were prepared via
tape casting, hot-press sintering technique using Y2O3 and MgO as sintering additives. Aligned α-Si3N4
whiskers were realized by modifying the tape casting technique. After tape casting, Si3N4 tape with good
flexibility and uniform pores can be obtained. Microstructures of the tape, green body and sintered sample
were observed by SEM images. The results show α-Si3N4 whiskers in Si3N4 tape and green body were
aligned preferentially along the tape casting direction. Si3N4 ceramics with aligned elongated grains are
developed by hot-press sintering technique based on the reaction between Si3N4 and the sintering
additives which lead to the liquid phase.
Multi-Step Sintering Method Study of HP Y-SiAlON Ceramics
Authors: Xu Jiu Jun , Shan Ying Chun , Li Jiang Tao , Song Qin Ji
Published: March 2009

Multi-step hot pressing sintering was adopted to prepare Y-SiAlON (Y0.4Si9.6Al2.4O1.2N14.8) at
1950°C for 60 min under 25 Mpa in nitrogen atmosphere, and the microstructure was studied. The phase
assemblages, microstructures and densification of the sintered samples were discussed in detail. In order
to contrast to multi-step sintering, one step sintering also was adopted. The results reveal that single-phase
α-SiAlON with elongated grain pattern is formed in the multi-step sintering specimens, because of
holding at low temperature in multi-step sintering is helpful to reduce the kinetics of crystal growth, the
mount of elongated grain in multi-step sintering samples is more than that of in one step sintering ones.
Spark Plasma Sintered AlN-BN Composites and its Dielectric Properties
Authors: Zhao Hai Yang , Wang Wei Min
Published: March 2009

A series of samples of hexagonal boron nitride-aluminum nitride (10-90, 15-85, 20-80, 25-75, 30-70wt.%) ceramic composites were prepared by spark plasma sintering in a nitrogen atmosphere at 1650 °C-1800 °C for 5min. Different amounts of CaF2 were added as sintering aids. The effects of CaF2 and sintering temperature on densification and dielectric properties were discussed. The addition of CaF2 enhances relative dielectric constant and loss tangent of the samples. The increase in sintering temperature promotes the densification and decreases the dielectric loss tangent. When being sintered at 1700 °C, the relative density, dielectric constant and dielectric loss tangent of the sample with 15wt.%BN are 98.04%, 7.15 and 6.31×10-4 respectively.
Machining Characteristics of AlN-hBN Composites in End-Milling and Precision Lapping Processes
Authors: Beck Si Young , Shin Bong Cheol , Cho Myeong Woo , Lee Eun Sang , Park Dong Sam , Yun Dae Jin , Cho Won Seung
Published: March 2009

In this study, the machining characteristics of developed AlN-hBN composites were
investigated in the end-milling and precision lapping processes. To achieve the objectives, material
properties of the developed AlN-hBN composites were evaluated according to the variation of hBN
contents. And, required experimental works were performed to investigate the machining characteristics
of the composites. First, the machiniability of the composite was evaluated in the end-milling process
under various cutting conditions, such as spindle speed, feederate, and depth of cut variations. Also,
generated micro cracks caused by the cutting process were investigated via SEM photographs. Next,
precision lapping experiments were performed under various conditions, and the results were estimated.
Effect of Tb Substitution on Electrical Characteristics and Microstructures of Bismuth Titanate Ceramics
Authors: Chen Min , An W.K. , Cai A.H. , Huang Chong Qing , Su K.L. , Liu J.
Published: March 2009

The electrical properties and Microstructures of Tb-doped bismuth titanate (Bi3.3Tb0.6Ti3O12) ceramic were investigated. XRD analyses revealed that the sample had Bi-layered perovskite structure. SEM micrographs showed randomly oriented and plate-like morphology. The remanent polarization (Pr) and coercive field (Ec) of Bi3.3Tb0.6Ti3O12 ceramic are above 25 μC/cm2 and 80 KV/cm, respectively.
Sintering and Properties of MoSi2 Matrix Composites Reinforced by Carbon Nanotubes
Authors: Qiao Ying Jie , Fang Shuang Quan , Zhang Xiao Hong , Song Le Ping
Published: March 2009

MoSi2 composites reinforced by carbon nanotubes were prepared by spark-discharge plasma
sintering (SPS), and the dispersion of carbon nanotubes in the MoSi2 was also discussed in this work. The
mechanical properties of MoSi2 reinforced by carbon nanotubes were measured. Investigation indicated
that the carbon nanotubes can be well dispersed by introducing the dispersant C12H25SO3Na and the
mechanical properties of the composites improved significantly. The mechanism that the composites
were reinforced and toughened were discussed in this work.
Study on the Mechanic Properties of DLC Films on Different Metal Substrates
Authors: Zhao Dong Cai , Ren N. , Ma Zhan Ji , Xiao Geng Jie , Wu Sheng Hu
Published: March 2009

To overcome the low adhesion of hydrogen-free DLC films on metal substrates, in this
studying, DLC films (0.9μm) were prepared with 3 types of interlayer (2 types of Ti/TiCx/DLC
interlayer and 1 type of Ti/TiNx/TiNxCy/DLC interlayer) on different substrates (W18Cr4V,
Cr12, GCr15, TC4, 40Cr, 9Cr18 and Cr18Ni9Ti). The internal stress of the films was calculated by
the bending of substrate (Si(100)). It was found that it is as high as 3.9GPa, and part of the high
residual stress of the DLC films was dissipated through a compound interlayers, and the thick films
achieved, and the pull tests found that the adhesion has been highly strengthened with a proper
interlayer. The films structure qualities were investigated by Raman spectroscopy and the results
indicate that the films have the same structure properties which suggests that the properties of the
DLC films can not been affected by substrates. The hardness is about 5000HV, defined by
nanoindentation techniques. The frictional properties were investigated by reciprocal sliding tests
and the friction coefficient was about 0.1, independent of their substrates. Thus our DLC films may
have great potential applications in precision parts tribological application.
Polycrystalline Columnar Diamond Film Deposited on Spherical Substrate by DC Arc Plasma CVD
Authors: Li Duo Sheng , Zuo Dun Wen , Lu Wen Zhuang , Chen Rong Fa , Xiang Bing Kun , Wang M.
Published: March 2009

Diamond film was deposited on spherical molybdenum substrate by DC arc plasma CVD
method. Diamond film morphology, purities and orientation evolution, obtained from atomic force
microscopy, scanning electron microscopy, Raman spectroscopy, X ray diffraction respectively, has
showed that grains on the growth surface are compact, continuous and uniform. Characteristic
diamond (111), (220), (311) peaks were found and (111) facets were predominant. It revealed that
diamond film was polycrystalline texture characteristic. There is a typical diamond Raman spectrum
peaks at 1332.0 cm-1, and not graphite and amorphous carbon characteristic peak. High purity
diamond film was deposited. When methane concentration was increased, diamond film has more
local clusters and vacancy defects such as voids, graphite inclusion, and hydrogen cluster. Therefore,
some important parameters such as methane concentration and substrate temperature should be
optimized in depositing diamond film.
The Preparation and Properties of TiN/Carbon Coatings by Ion Beam Assistant Magnetron Spurting Deposition
Authors: Du Jun , He Wen J.
Published: March 2009

TiN/carbon multilayer coatings were deposited on M2 and GCr15 wafers by ion beam
assistant magnetron spurting deposition (IBMSD). The hardness, elastic modulus, fracture toughness,
adhesion strength and tribological properties were investigated. The results show that TiN coating by
means of static recoil N+ doped interface preparation and Ar+ beam assistant magnetron spurting has 2
times adhesion strength, 5 times hardness of none-beam-assistant TiN coating. The wear rate of
GCr15 wafer with TiN(2h)/Carbon(4h) multilayer coating is 0.36×10-15m3/Nm,1/5 of that of GC15
wafer without coating. The wear rate of M2 wafer with TiN(2h)/Carbon(4h) multilayer coating is
2.8×10-15m3/Nm, 1/8 of that of M2 wafer without coating. The friction coefficient of GCr15 wafter
with TiN(2h)/Carbon(4h) multilayer coating is lower than 0.15, and that is 0.04 for M2 wafer. These
results indicate that thickness ratio of TiN to carbon is important for the tribological properties of
TiN/carbon coating, thick lubricant carbon/thin load-support TiN multilayer coating has better
comprehensive tribological properties.
Microstructure and Hardness of Ti-Si-C-N Coatings
Authors: Guo Yan , Ma Sheng Li , Xu Ke Wei , Bell Thomas , Li Xiao Ying , Dong Han Shan
Published: March 2009

Series Ti-Si-C-N coatings with different carbon were deposited on a high-speed-steel
substrate by means of pulsed direct current plasma enhanced chemical vapor deposition (PECVD).
The structure and hardness were subsequently investigated using X-ray diffraction, transmission
electron microscopy and microindentation measurements. It was found that the carbon content had a
profound effect on the microstructure and hardness of the Ti-Si-C-N coatings. The results indicated
that these coatings consisted of the dominant nanocrystalline Ti(C, N), accompanying with a small
amount of silicide (TiSi2, Si3N4 or SiC) dispersed within the dominant phase. An increase in C
content resulted in the decrease in the grain size and the increase in fcc-structure lattice parameter.
A maximum hardness of 48 GPa was achieved for a two-phase {Ti (C N) + SiC} structure at the C
content of 38.6 at.%.
Influence of Bi-Layer Thickness on the Structure and Properties of Multilayered TiN/CrN Coatings by Cathodic Arc Plasma Deposition
Authors: Chang Chi Lung , Ho Wei Yu , Liu Wen Jen , Hwang J.J. , Wang Da Yung
Published: March 2009

TiN/CrN nanoscale multilayered coatings have been deposited using cathodic arc
evaporation system. The coatings were deposited using one Ti target and one Cr target with a fixed
power output in the processes, whilst the bi-layer thickness was varied by rotation of the substrate
holder to obtain different nanoscale multilayered period thickness. The texture structure, residual
stress and nanoscale multilayer thickness of the coatings were determined by X-ray diffraction using
both Bragg-Brentano and glancing angle parallel beam geometries. Hardness and adhesion strength of
the coatings were measured by Vicker's and Rockwell-C indentation methods. It has been found that
the structural and mechanical properties of the films were correlated with nanoscale bi-layer thickness
and crystalline texture. The maximum hardness of nanolayered TiN/CrN multilayer coatings was
approximately 28 GPa, which the bi-layer thickness was 4 nm.
Effect of UV-Irradiation on Anodized Films Formed on Titanium in 0.1M H2SO4 Solution
Authors: Yao Yu Hong , Nanjo Hiroshi , Liu Jiang Nan , Xia Zheng Bin , Wang Zheng Pin , Wei Jian Feng
Published: March 2009

The titanium anodizations in 0.1 M sulfuric acid solution at different treated potentials and
the effects of UV-irradiation on the anodized films were investigated by spectroscopic ellipsometry
(SE), atomic force microscopy (AFM) and scanning tunneling microscopy (STM). The results
showed that the thickness of anodized films decreased in air within 280 min over 500 mV vs.
Ag/AgCl. The features of parameters tanΨ and cosΔ in SE were in accord with the polarization curve
and the thickness of anodized films, respectively. UV-irradiation could greatly decrease the thickness
of the anodized films and provably assisted the reconstruction of anodized titanium films from an
amorphous and porous structure to a compact structure. Regardless of UV-irradiation, the cosΔ and
tanΨ were still in good agreements with the thickness of anodized films and the polarization curve,
respectively. It was also found that UV-irradiation could decrease the surface roughness and make a
wider atomically flat terrace on the anodized titanium surface.
Effect of pH Value on the Electrodeposition Potential of Cu-In Alloy Film
Authors: Yang H.X. , Song Zhen Lun , Song Yong Wei , Zhang Hui
Published: March 2009

Electro-deposition Cu-In alloy can act as the precursor film to prepare CuInSe2
compound by selenating treatment. The effect of pH value on the electrodeposition potential of
Cu-In alloy was investigated by electrochemical measurements in this paper. The relationship
between the pH values and deposition potential was analyzed. Then uniform Cu-In alloy film was
successfully prepared based on the special potential and pH.
Deposition of Amorphous Diamond Films on Different Substrates by Electrolysis of Methanol Solution
Authors: He Y.Y. , Zhang G.F. , Li Guo Q. , Hou X.D.
Published: March 2009

Amorphous diamond films were deposited on both (100) silicon and 316L stainless steel
substrates at atmospheric pressure and low temperature (60°C) with a direct current pulsed power
supply using methanol/additive solution as electrolyte. The morphology and microstructure of the
films were analyzed by scanning electron microscopy (SEM) and Raman spectroscopy. The friction
and wear behavior of the films were examined on the CERT test system. The SEM observations
showed that the films consisted of fine and compact ball-like grains with about 300nm in diameter.
Raman spectroscopy analysis confirmed the diamond structure by the presence of strong peaks at
1333cm-1 for both substrates. The friction coefficient of the films deposited on both substrates against
WC ball was about 0.10 at ambient conditions. The active additive could play an important role not
only in improving adhesive strength between the films and substrates, but also in increasing relative
content of diamond phase in the films.
Thermal Stability of Nitrogen Expanded Austenite Formed by Plasma Nitriding on AISI304 Austenitic Stainless Steels
Authors: Wang Liang , Li Yang , Wang Yi Zuo
Published: March 2009

The effect of thermal annealing temperature on the microstructure and phase composition of
nitrided layer formed on AISI 304 stainless steel by plasma nitriding were investigated. The phase
composition and structure of the nitrided have been analyzed by X-ray diffraction (XRD) and
scanning electron microscopy (SEM). The XRD analysis of nitrided samples at 420oC showed the
presence of γN phase in the nitrided layer. The temperature at which the nitrogen expanded austenite
started to decompose was about 450oC. Above this critical temperature the γN phase transformed
into a mixture of CrN and α-phase. The surface hardness of nitrided layer also slightly changed
with annealing temperature.
Electron Beam Surface Alloying of a Magnesium Alloy with Al
Authors: Ye Hong , Yan Zhong Lin
Published: March 2009

Magnesium alloy is an important engineering materials，but the wider application is
restricted by poor corrosion and wear resistance. In the present study, an attempt was made to enhance
corrosion resistance and microhardness of Mg alloy AZ91D by electron beam alloying. Flame spray
method was used to prepare Al coating on the surface of AZ91D magnesium alloy, then remelted by
high power electron beam. The microstructure and composition of the coating were analyzed in detail.
Al-Mg diffusion was produced between the coating and the substrate to lead to the re-distribution of
alloy elements in the melted layer. The coating was mainly composed of Al-Mg solid solution, Mg-Al
intermetallic compounds and Mg-Al solid solution transition zone. Microhardness of the alloying
layer was enhanced to 220 HV0.05 as compared to 70-80 HV0.05 of the substrate, due to the
intermetallic phase formation, such as Mg2Al3 and Mg17Al12. These phases were good to improve
anticorrosion property of AZ91D alloy．
Change of Hydrophobicity on Silicone Rubber Modified by CF4 Capacitively Coupled Plasma and Inductively Coupled Plasma
Authors: Gao S.H. , Liu Y. , Lei M.K. , Wen Li Shi
Published: March 2009

Silicone rubber (SIR) samples are exposed to CF4 capacitively coupled plasma (CCP)
and inductively coupled plasma (ICP) at radio frequency (RF) power of 60–200 W for a treatment
time up to 20 min, respectively. Static contact angle is employed to estimate the change of
hydrophobicity of the silicone rubber modified by the two coupled types of CF4 RF plasma. A
milder enlargement of static contact angle of SIR samples modified by ICP treatment is observed
compared with that by CCP treatment. The hydrophobicity of the modified SIR surface by CCP
treatment increases to a maximum, and further decreases toward the hydropholicity. The higher
self-bias on the SIR samples being modified by CCP treatment than that by ICP treatment leads to
the more dramatic physical and/or chemical reaction on the SIR surface, resulting in the
competition between fluorination and ablation or etching.
Numerical Simulation on Molten Process of GaAs Target Bombarded by Intense Pulsed Ion Beam
Authors: Sun Jian Jun , Li Jian Feng , Liu Zhen Dong , Li Guo Qing
Published: March 2009

Based on energy equation, a one-dimensional model was used for the evolution of the
temperature distribution in the GaAs target bombarded by Intense Pulsed Ion Beam (IPIB). The
numerical simulation was completed according to a fitting result from the waves of the ion diode
magnetically insulated and the ion current density detected by Faraday cup at the focus region of the
Russian TEMP type accelerator. The parameters of the IPIB are: ion beam composing of H+ 70%,
C+ 30%, average value of pulsed voltage 300kv, the maximal peak of current density of the beam
260 A/cm2, pulsed width 60ns. The numerical simulation results reveal the temperature distributing
in the samples and provide quantitative informations of the first melting time at 10ns and melting
layer thickness 2.4 μm after one pulse.
The Remanufacturing System Based on Robot MAG Surfacing
Authors: Zhu Sheng , Meng Fan Jun , Ba De Ma
Published: March 2009

A remanufacturing system based on robot MAG surfacing has been developed recently. In
this paper, the work principle, functions and composition of this system are introduced. A worn metal
part to be remanufactured should be preprocessed firstly, and the defective model of the part gained
by reversing engineering technology is compared with normal model of the metal part, then the
prototyping path layout is carried out combined with MAG welding process, finally the
remanufacturing prototyping is implemented. The remanufacturing system is composed of robotic
system (as executing machine), 3D laser scanner (as reversing scanning device), digital pulse MAG
welding power source (as prototyping equipment), desk computer (as central control unit) and
software modules that support various functions. The functions of the remanufacturing system
comprise calibration of system, part reversing measurement, data processing, defective model
reconstruction, welding remanufacturing prototyping path layout and etc. It is indicated that the
exploitation of the remanufacturing system will provide an effective way for the remanufacturing of
metal defective parts.
Model of Heat and Mass Transfer in Atmospheric Pressure Plasma Arc (APPA) Cleaning Metal Surface
Authors: Xu Wen Ji , Meng J.B. , Fang Jian Cheng , Wang Xu Yue
Published: March 2009

According to analyzing the principle of atmospheric pressure plasma arc (APPA) cleaning
metal surface, a model of heat and mass transfer is put forward with using transient-state heat transfer
equation about interior heat source and Arrhenius equation of chemical reaction kinetics theory. With
finite volume method, the one dimensional control differential equation is transformed into discrete
control equation, which is calculated numerically and analyzed with the using of implicit scheme.
Taken cleaning lubricant film as an example and analyzed temperature distribution of cleaning film
on metal surface, the result indicates that the temperature of film has a strong effect on its removal rate
which improves with increasing temperature. In order to both avoid damaging the workpiece surface
owing to higher temperature and ensure removal rate of the film, there exists an appropriate
temperature under given calculation conditions.
Influence of Oxygen Plasma Treatment on Surface Properties of Armos Fiber
Authors: Chen Ping , Wang Jing , Zhang Cheng Shuang , Lu Chun , Ding Zhen Feng , Pan Shi , Qi Wen , Sun Jing Chao , Li Jian Feng
Published: March 2009

Armos fiber (F-12 aramid fiber in paper) was provided with broad application foreground
as reinforcement material for advanced composites in aviation and spaceflight field, due to its
outstanding properties, such as high modulus, high strength, high temperature resistance, erosion
resistance and so on. However, the exertion of property was still limited by slippery surface, low
surface energy and weak interfacial adhesion performance. In this study, the effects of oxygen plasma
treatment time on polar functional groups introduced onto the fiber surface, surface free energy and
surface topographic images were discussed by X-ray photoelectron spectroscopy (XPS) analysis,
dynamic contact angle analysis system (DCA) and atomic force microscopy (AFM), respectively. It
was found that the content of oxygen element and polar functional groups on fiber surface were all
increased obviously after oxygen plasma treatment. The content of oxygen element on surface for
untreated F-12 aramid fiber was 11.13%, while it increased to 15.20% after oxygen plasma treatment
for 10 min; The content of polar functional groups on surface for untreated F-12 aramid fiber was
28.14%, while it increased to 38.11% after oxygen plasma treatment for 10 min. The polar
component (γp) of fiber surface energy increased sharply from 6.82 mN/m to 36.68 mN/m after 10
min plasma treatment, the total surface free energy was increased from 46.26 mN/m to 64.66
mN/m.The results indicated that oxygen plasma treatment had introduced a large amount of reactive
functional groups onto the fiber surface, and these groups can form together as covalent bonding to
improve the surface wettability and increase the surface energy of fibers. At the same time, oxygen
plasma treatment was able to generate a mass of bulges and grooves on F-12 aramid fiber surface,
which had an active effect on increasing the chemical bond and mechanical function between fiber
and resin and enhancing the interfacial adhesion performance of composite. The fiber surface grooves
had been increased with the time prolonging before 10 min while decreased after 10 min, the results
maybe relate to partial organic on fiber surface melting. It had an adverse effect on the interfacial
adhesion properties of composite. Therefore, the optimum plasma treatment time was between 5 min
and 10 min.