bluuebunny/crossref_metadata_2025 huggingface dataset:
YSZ Thin Films Prepared by a Novel Powder Coating Process on Porous NiO-YSZ Cermet
Authors: Bao Wei Tao , Jiang Yin Zhu , Zhu Guang Yan , Gao Jian Feng , Meng Guang Yao
Published: March 2009

Dense YSZ thin film with a thickness from 2 to 15 µm on porous Ni-YSZ anode support was fabricated by a novel powder coating process. The performance of the cell with a composite of Sm0.8Sr0.2CoO3- YSZ (40 wt.%) as cathode was examined over a temperature range from 550 to 800 °C, using H2 -3% H2O as fuel and air as oxidant. The maximum power density of the cells was over 300
mW/cm2 at 800 °C. The open circuit voltage of the cells reached 1.1 V at 750 °C, illustrating the full dense of the YSZ electrolyte. The anode-electrolyte interfacial resistances were negligible in comparison with that of cathode-electrolyte, indicating the good coherency of the YSZ electrolyte to the anode support. These results demonstrate the reliability of this novel process for thin electrolyte SOFCs.
Preparation, Dielectric and Magnetic Properties of Barium-Ferrite-Containing Microcrystalline Glass Ceramic by Citrate Sol-Gel Process
Authors: Zhang Hai Jun , Jia Xiao Lin , Yao Xi , Zhang Liang Ying
Published: March 2009

Four kinds of barium-ferrite-containing microcrystalline glass ceramics, such as
BaFe12O19/SiO2, BaFe12O19/SiO2-B2O3, BaFe12O19/SiO2-B2O3-K2O and BaFe12O19/SiO2-Al2O3-K2O were prepared by citrate sol-gel process, in which inceptive formation temperatures varied from 850°C to 1100°C. The complex dielectric constant and complex permeability of those glass ceramics were measured at 0.1-5.0GHz, and the frequency dependence of complex dielectric constant and permeability was studied. The microcrystalline glass ceramics were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM).
Preparation and Magnetic Properties of Y-Type Ferroxplana by Sol-Gel Method
Authors: Bai Yang , Zhou Ji , Gui Zhi Lun , Li Long Tu
Published: March 2009

The preparation and magnetic properties of Y-type ferroxplana were investigated. Y-type ferroxplana of composition Ba2Zn1.2-xCoxCu0.8Fe12O22 was prepared by citrate sol-gel autocombustion process. X varied from 0 to 1.2. Phase formation was characterized by powder X-ray diffraction (XRD). The microstructure was observed via scanning electron microscopy (SEM). The frequency spectra of initial permeability were measured via an impedance analyzer. Results reveal
that a well-defined Y-type phase can be formed after the auto-combusted powders were annealed at 900oC. The synthesized nano-sized powder is very active and can be sintered well at 900oC. The sintered samples have fine-grained microstructure. The samples exhibit excellent magnetic properties in hyper-frequency. As zinc content increases, the initial permeability is enhanced and the cut-off frequency decreases.
Synthesis and Characterization of Monodispersive In2O3 Particles
Authors: Lin Sung En , Wei Wen Cheng J.
Published: March 2009

Monodispersive and uniform particles have many potential applications. The objectives of this study are trying to synthesize and control the morphology of monodispersive indium oxide (In2O3)particles through hydrothermal process with the help of PVP (polyvinylpyrrolidone) and urea additions. Various cubic, ellipse, or shuttle-like In2O3 particles were synthesized by using hydrothermal conditions
(65-85oC). The effects of Sr nitrate were studied. Spherical particles could not be synthesized. The aspect ratio of the In2O3 particle reduced as the concentration of Sr nitrate increased. Crystalline In2O3 phase appeared above 300oC.
The Application of Porous Anodic Aluminum Oxide Membrane in Luminescence
Authors: Qiao Bin , Tang Zi Long , Zhang Zhong Tai , Zong Rui Long
Published: March 2009

In this article, the anodic aluminum oxide (AAO) was prepared by two-step anodizing process in oxalic acid electrolyte. And a blue-emission of AAO itself attributed to the oxalate was observed. The AAO membrane with ordered nano-sized porous structure was an important membrane to produce nano-materials. And luminescent nano-particles embedded in AAO, such as ZnO in this article, possessed notably special performances which were due to the quantum size
effect and the special environment provided by the nano-pores. Since AAO membranes possessed a unique structure, in this paper, an assumption about the application of the membrane in field emission display (FED) and electroluminescence (EL) was proposed.
Preparation and Luminescence of Y2O3:Eu3+ Nanopowder
Authors: Chen Ji Yang , Shi Ying , Shi Jian Lin
Published: March 2009

Eu3+ doped Y2O3 nanopowder was prepared by a novel complex precipitation process in which the mixture of ammonium water and ammonium hydrogen carbonate was adopted as complex precipitant. The precipitant precursor and the resultant powder were characterized by FT-IR, XRD, SEM and TEM. The resultant weakly agglomerate and spherical particles have a uniform grain size about 20nm after calcined at 850°C for 2 hours. 3mol% Eu3+ doped Y2O3 nanopowder shows an intense red luminescence at 612nm under UV excitation.
Preparation and Upconversion Luminescence of YAG: Er3+ Powders
Authors: Liu Min , Wang Sheng Wu , Zhang Jian , An Li Qiong , Chen Li Dong
Published: March 2009

Y2.85Er0.15Al5O3 was prepared by combustion process. Phase evolution of the synthesized powders was determined by XRD. Single-phase cubic YAG: Er3+ crystalline powders were obtained by calcining the combusted product at 1000°C and no intermidiate phase was observed. SEM morphology showed that the resultant YAG: Er3+ powders were porous. Upconversion emission spectra were measured on the powder compact pumped by a 980nm continuous wave diode laser. The relationship between pump power and luminescence intensity suggested that a two-photon process is active in this sample. The upconversion machanism of YAG: Er3+ system was also discussed.
Texture Development of Dip-Coated Bi-2223 Thick Films on Ag Substrate
Authors: Song Yang , Huang Yong , Han Zheng He
Published: March 2009

Preparing Superconducting Bi-2223 films by dip-coating method is innovative and
valuable. The advantages of this technique are low cost and precise stoichiometric. Controlling the evaporation of Pb efficiently can improve the formation of Bi-2223 phase. Textured BSCCO superconductors are studied and a mechanism for alignment of BSCCO grains addressed.
Modification of Ba6-3xSm8+2xTi18O54 (x=2/3)Microwave Dielectric Ceramics by Nd/Bi Co-Substitution on A-Site
Authors: Qin N. , Chen X.M.
Published: March 2009

Ba6-3xSm8+2xTi18O54 microwave dielectric ceramics were modified by Nd/Bi co-substitution for Sm on A-site. According to XRD and SEM analysis, a single-phase solid solution with new tungsten bronze-type structure was formed in low-Bi-substituted region. Bi was effective on increasing dielectric constant, while led to a decreased Qf value and an increased negative tf. The co-substituting approach
exhibited the advantage in improving e and compensating Qf and tf value.
Nanostructured Surface Coating Layer of Calcium Carbonate Composite Particles
Authors: Fan S.M. , Gai Guo Sheng , Yang Yu Fen , Fu Shao Yun , Miao He Zhuo
Published: March 2009

The calcium carbonate composite particles with nanostructured surface were prepared by heterogeneous nucleation. The calcium carbonate composite particles consisted of a core of groundcalcium carbonate particle and a shell of nanometer calcium carbonate particles. The thickness of theshell of composite calcium carbonate was observed by TEM. The bond intensity between the core and the
shell was measured by means of ultrasonic comminution and stirred ball milling. It was found that the composite calcium carbonate had a compact structure. The linkage between the core and shell was so strong that it must be chemical bond instead of physical adsorption.
Photocatalytic Properties of the Transition Metal Doped TiO2 Powder Prepared by Sol-Gel Process
Authors: Whang Chin Myung , Kim J.G. , Hwang Hae Jin
Published: March 2009

Transition metal-doped TiO2 powders as a photocatalyst were prepared by sol-gel process and Sb, Bi and Nb were introduced into them as dopants. The photocatalytic behaviors of the doped TiO2 powder were studied as a function of dopant, doping concentration and preparation conditions. X-ray diffraction, FT-Raman, B.E.T. and scanning electron microscopy were applied for structural and
microstructural studies. Optical properties of the doped TiO2 powders were studied by UV-Visible Spectrometer and photocatalytic activity of the doped TiO2 was characterized in terms of the degradation of 1,4-dichlorobenzene. X-ray difraction analysis showed that doping with a transition metal ion suppresses anatase-to-rutile
phase transition compared with the pure TiO2. The Sb and Nb-doped TiO2 powders did not exhibit any other diffraction peaks except those belonging to TiO2. On the other hand, a diffraction peak of Bi4Ti3O12 appears for 5 at.% Bi-doped samples. All of the doped TiO2 powders had higher specific surface area than undoped TiO2. Surface area increased with increasing dopant concentration depending on the dopant, from 33.9 m2/g to 55.4m2/g. The UV-visible absorption spectra of doped samples were red-shifted by 20~50nm according to the doping level. Also transition metal doped TiO2 powders exhibited better photocatalytic activity than the undoped TiO2. The increase in photoactivity is probably due to the increase in the interfacial electron transfer, red shifts, and better crystallinity.
LiCoO2 Cathode Material Coated with Nano-Crystallized ZnO by Sol-Gel Method
Authors: Wang Jye Hwa , Fang Ting , Duh Jenq Gong
Published: March 2009

LiCoO2 spinel is one of the most promising cathode materials for Li-ion batteries. However, the capacity fading is aggravated at high voltage, resulting from cathode degradation and electrolyte decomposition owing to over-charging. To improve structural stability, surface modification is an effective method. In this study, nano-crystallized ZnO was coated on the surface of commercial LiCoO2 powders via sol-gel method. The correlation among the amount of coated ZnO, microstructure of
modified cathode and the cycling behavior of surface-treated LiCoO2 powders is discussed. Moreover, the effects of cycling for cathodes with as-derived powders on the phase and morphology are also considered. The surface morphology observed from the scanning electron microscope (SEM) images shows that nano-crystallized and spherical ZnO particles with an average size of about 20 nm have
developed after coating. The size of ZnO nanocrystallites is related to the initial concentration of Zn2+ cations. In comparing the characteristics of bare and coated LiCoO2 powders, improvement in cyceability of the ZnO-coated cathode is explored. It is confirmed that Zn2+ ions diffuse into the surface region of LiCoO2 particles. To reveal the effects of Zone coating on enhancing the electrochemical properties of LiCoO2 cathode during charge and discharge, the morphological differences between the cathode material before and after cycling are discussed.
The Microstructural Evolution of Mn3O4 Hausmannite during Autoxidation
Authors: Fang Ting , Duh Jenq Gong , Tsai Sue Yueh
Published: March 2009

Mn3O4 hausmannite, which is a normal spinel with the Mn2+ in the tetrahedral site and the Mn3+ in the tetrahedral site, is one of the most stable manganese oxides. Variation in the valence of Mn ions (2+, 3+ and 4+) contributes to several different structures of manganese oxides. The autoxidation of precipitated manganese hydroxide in an alkaline solution is a practical approach to
synthesize hausmannite (Mn3O4) at low temperature. During the process, the particle size and morphology of derived products were totally different from the precursors even though nanometer-sized Mn(OH)2 crystals were fabricated at first. It was observed that the variation was resulted from the accumulation of produced Mn3O4 crystallites which departed from the original crystals. This study has not only discussed the influence of reactant concentrations on the particle size
and morphology of derived powders, but also revealed the morphological transformation of crystals involved in autoxidation with the aid of electron micrographs
Hydrothermal Synthesis of Free-Standing Co3O4 Nanocubes
Authors: Yang Juan , Quaresma S. , Mei Sen , Ferreira José Maria F. , Norby P.
Published: March 2009

Mono-dispersed free-standing Co3O4 single crystals were synthesized by hydrothermally treating Co(NO3)2·6H2O aqueous solutions with addition of NaNO3 and tetraethylammonium hydroxide (TENOH). For comparison, samples were prepared using sodium hydroxide (NaOH) instead of TENOH. The obtained phases were greatly dependent on the types of alkalis and their concentrations. TEM images of TENOH-derived samples showed that the formation of free standing
spinel Co3O4 nanocubes with sizes of 40-60 nm dominate over all the observation ranges for the samples with lower TENOH concentrations. While brucite-like Co(OH)2, Co3O4 and rod-like CoOOH appeared in the NaOH-derived sample, TENOH favoured the formation of Co3O4 nanocubes compared with NaOH.
A Study of Slurries in Aqueous Tape Casting Processing
Authors: Cui Xue Min , Huang Yong , Zhou Ji , Wang Chang An , Ouyang Shi Xi
Published: March 2009

As a good binder for aqueous Al2O3 suspensions tape-casting process, a commercial styrene-acrylic latex binder had been investigated. This paper studied on the rheological behaviors of the suspensions and drying process of aqueous slurries with latex binder system, and the research results indicated the rheological behaviors was affected by pH value, solid loading and dispersant (PAA-NH4) additives; and the drying speed of slurries was most decided by drying temperature and slurry coating thickness.
Effect of Bi Content on the Dielectric Property of SBN Ceramics Prepared by Spark Plasma Sintering
Authors: Deng Xiang Yun , Li Bao Rang , Wang Xiao Hui , Li Long Tu , Gui Zhi Lun
Published: March 2009

SrBi2Nb2O9 (SBN) with different Bi2O3 contents were prepared by solid-state reaction method and then spark plasma sintering. The Influence of Bi2O3 on the properties of SBN was studied. The results showed that the increased Bi2O3 contents can enhance densification and improve the dielectric properties.
This might have close relation to the low melting point of Bi2O3 and special sintering way of SPS, which usually results in some change in micro-structure.
BaO-Nd2O3-TiO2 Nano-Ceramics Prepared by SPS Technology
Authors: Xiang Yong , Xie Dao Hua , Song Kuan Xiu , Zhao Yu Shuang , Li Jing Feng
Published: March 2009

Fine grained and dense dielectric ceramics of the BaO-Nd2O3-TiO2 system have been fabricated by the most advanced Spark Plasma Sintering (SPS) technology, whose average grain size is about 100nm as determined by SEM. XRD showed that the diffractive peak of the sample was broadened clearly. The nano-ceramic microstructure formed by SPS is due to the high pressure up to 50 MPa, low
temperature (1000°C) and fast sintering (1 minute). The BaO-Nd2O3-TiO2 ternary nanoceramic sample, which consists of the main phase Nd2Ti2O7 with perovskite-like layer structure (PLS) and the secondary phase BaNd2Ti4O12（Ba4.5Nd9Ti18O54）with perovskite-like tungsten bronze structure, was prepared for the first time by rapidly sintering nano-particles of the xBaO×(0.35-x)Nd2O3×0.65TiO2 compound. Those two phases are formed in BaO-Nd2O3-TiO2 micron-grained ceramics prepared by normal sintering of the nano-particles at 1300°C, resulting in good dielectric characteristics for microwave ceramics; however,
dielectric characteristics are significantly degraded in the SPS-sintered samples probably due to the carbon contamination from the graphite SPS dies.
Shape Forming and Microwave Sintering of Thin Wall Tubular Lithium Aluminate
Authors: Ling Yun Han , Lin Wei , Jiang Zuoz Hong , Bai Xin De
Published: March 2009

Thin wall tubular Lithium aluminate ceramics have special application background. The microwave synthesis of LiAlO2 ultrafine powder, shape forming and microwave sintering of lithium aluminate pipes with 1mm in thickness were conducted in this paper. The results showed: (1) A controllable ratio of alpha to gamma phase LiAlO2 with average particle size of 0.3 µm can be synthesized via microwave radiation at temperature of 650-800°C within an hour; (2) Cold press and
cold isostatic press are feasible methods to form LiAlO2 thin-wall tube and their mechanical properties are superior to those molded via hot pressure casting. (3) Lithium aluminate ceramic was successfully fabricated via microwave sintering, a uniform crystal size within 2-4µm, a typical bimodal pore size distribution and a average compressive strength more than 600MPa were obtained
at 1300°C for 30min.
Effects of Substrates on the Composition and Microstructure of TiO2 Thin Films Prepared by the LPD Method
Authors: Yu Huogen , Yu Jia Guo , Cheng Bei , Ao C.H. , Lee S.C.
Published: March 2009

TiO2 thin films were prepared on soda lime glass, fused quartz and stainless steel substrates by liquid phase deposition (LPD) method from a (NH4)2TiF6 aqueous solution upon the addition of boric acid (H3BO3), and then calcined at 500oC for 2 h. The prepared films were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It was found that the substrates obviously influenced the element composition and microstructure of TiO2 thin films. Except Ti, O and a small amount of F and N elements, which came from the precursor solution, some Si (or Fe) element in the thin films deposited on soda lime glass and quartz substrates (or on stainless steel substrate) was confirmed. The Si (or Fe) element in the thin films could be attributed to two sources. One was from the SiF6
2- ions (or FeF6 2- ions) formed by a reaction between the treatment solution and soda lime glass or quartz (or stainless steel) substrates. The other was attributed to the diffusion of Si (or Fe) from the surface of substrates into the TiO2 thin films after calcination at 500oC. The Si (or Fe) element in the TiO2 thin films could behave as a dopant and resulted in the formation of composite SiO2/TiO2 (or Fe2O3/TiO2) thin films on the substrates.
Preparation of TiO2 Thin Films Using Inorganic Peroxo Titanic Complex and Autoclaved Sols as Precursors
Authors: Ge Lei , Xu Ming Xia , E Lei , Tian Yu Ming , Fang Hai Bo
Published: March 2009

A new sol-gel method was introduced to prepare titanium oxides (TiO2) photocatalytic thin flms using peroxide (H2O2) and titanyl sulfate (TiOSO4) as raw materials. The TiOSO4 solution was recipitated by adding ammonia solution, then peptized with 30% H2O2 solution to get a yellow, table, neutral, and transparent liquid (peroxo titanic complex sol). When the peroxo titanic complex
sol was autoclaved above 80°C for 2h, it changed to a stable, semitransparent sol containing eedle-like, ultra-fine anatase crystals less than 20nm in diameter. Titanium oxide (anatase) films sed for photocatalysis can be prepared on substrates by a dip-coating technique using peroxo titanic omplex and autoclaved sols.
Synthesis and Microstructure of Barium Bismuth Titanate Thin Films Using a Sol-Gel Technique
Authors: Xie Dan , Pan Wei , Ren Tian Ling , Liu Li Tian
Published: March 2009

The preparation and the microstructure of BaBi4Ti4O15 (BBT) thin films were reported in the paper. BBT thin films were fabricated on silicon substrate using a modified Sol-Gel technique. A key issue of Sol-Gel processing is the chemical reaction and mechanism of precursor solution, which governs the crystallization and characteristics of the final oxide layer. Ethanolamine is an effective complexation
reagent of Bi3+, which could moderate the acidity of precursor. When pH value is about 3.5, the stable and uniform BBT precursor solution could be obtained. The Bi-layered perovskite structure of BBT forms at 750°C. The morphology of the grains in BBT thin films is spheroidal and the grain size is about 120nm.
Study on Alkyd-Based Electrically Conductive Coatings
Authors: Du Zhi Ming , Cong Xiao Min , Wang Peng
Published: March 2009

Carbonaceous fillers have been widely applied in electrically conductive coatings due to their cheaper, steady electrically conductive capability and other excellent performances. Electrically conductive coatings were synthesized by using graphite and carbon black as fillers in the alkyd resin matrices. Influences of various fillers on electrical conductivity of coatings have been investigated in detail.
Study of Novel Self-Humidifying PEMFC with Nano-TiO2-Based Membrane
Authors: Cheng Wang , Mao Zong Qiang , Xu Jing Ming , Xie Xiao Feng
Published: March 2009

We propose self-humidifying polymer electrolyte membranes with highly dispersed
nanometer-sized Titanium dioxides for proton exchange membrane fuel cells operated with dry H2 and O2. The nanosized TiO2 particles that have hygroscopic property are expected to adsorb the water produced from the cathode reaction and to release the water once the proton exchange membrane needs water. The preparation technology of nano-TiO2 particles in a commercial Nafion 112
membrane via novel in situ sol-gel reactions was developed, resulting in a semitransparent membrane with uniform distribution of TiO2 in the proton exchange membrane. It is found that Proton conductivity increases observably by dispersing 3 wt % nano-TiO2 in the Proton exchange membrane at low humidity condition, and the newly prepared TiO2-PEM improve the self-humidifying performance of Proton exchange membrane fuel cell.
La2O3/Al2O3/B2O3 Based Glass-Ceramics for LTCC Application
Authors: Wei Wen Cheng J. , Chen Chih Lung , Roosen Andreas
Published: March 2009

La2O3-Al2O3-B2O3 (LAB) glass with Al2O3 particulates is a lead-free, non-alkali, and low-sintering temperature glass-ceramic system, which has been developed for LTCC application. The glass melting and sintering process window of the LAB systems were investigated. A systematic study on the wetting behaviors of the LAB glass on alumina plate, microstructures and crystallization in the glass-ceramics had also been conducted. The densification and crystallization temperatures of the glass-ceramics took place as low as 800oC. The interface condition of layer glass-ceramics with Ag electrode was also characterized. No obvious interfacial diffusions were observed.
Design of Multiphase Materials
Authors: Tuan Wei Hsing
Published: March 2009

In the present study, several principles are introduced as the guidelines to design multi- phased materials. Each phase in the multiphase material can offer one function or property to the material. The functions contributed from the phases within the multiphase material can interact with each other. Such interactions can be tailored by suitable microstructure design. The Al2O3-ZrO2-Ni multiphase material is
used to demonstrate the applications of the design principles.
Study on Preparation of Spherical Zirconia Powder in Microemulsion System and its Surface Characteristics
Authors: He Jintao , Ma Tian , Huang Yong , Yang Jin Long
Published: March 2009

In this paper, a W/O microemulsion system composed of cyclohexane / water / TritonX-100 / hexyl alcohol is adopted to prepare ultrafine spherical zirconia powder via the reaction between the precipitant and zirconium salt solved in the nano reactors. Furthermore, the powder’s surface characteristics and aqueous dispersibility that strongly depends on the post-treatment process are
investigated thoroughly.
Preparation of Zirconia Nanopowders in Ultrasonic Field by the Sol-Gel Method
Authors: Li Xiao Xi , Chen Ling , Li Bing , Li Lin
Published: March 2009

Zirconia nanopowders were prepared in the ultrasonic field by the sol-gel method and the sonochemical effect on the structure of zirconium hydroxide and the zirconia nanopowder properties were systematically investigated in this work. Ultrasound was introduced into the different stages of the
synthesis of zirconia nanopowders in sol-gel reaction system, and zirconium hydroxides and the zirconia nanopowders with different properties were obtained. The results indicated that ultrasonic cavitation could not only disaggregate the agglomerates of zirconia colloidal particles but also reduce the amount of
coordinated H2O, free H2O and free hydroxyl groups of the zirconium hydroxide colloidal particles, thus effectively preventing the formation of hard agglomerates in zirconia powders. Moreover, the effects of different ultrasonic output powers and treatment cycles on the structure and properties of ZrO2 nanopowders were studied by TEM, XRD and SAXS. Zirconia nanopowders with an extremely small
crystallite size (10.3 nm) and a narrow size distribution were yielded with 520 W ultrasound for 6 treatment cycles on the formation period and 600 W ultrasound for 2 treatment cycles on the washing period. It is concluded that the ultrasonic field is a potential method for nanopowder preparation.
Preparation of Refractory Nozzle by Gelcasting of Zirconia Suspensions with Coarse Particles
Authors: Zhang Li Ming , Ma Tian , Li Hai Feng , Huang Yong
Published: March 2009

Zirconia suspensions with coarse particles were prepared and the rheogical behavior and sediment stability of such suspensions with different dispersants were studied. It was found that ZrO2 suspension stabilized with TAC (tri-ammonium citrate) has an obvious shear-thinning behavior and rapid settlement; In contrast, the suspension stabilized with arabic gum shows a shear-thickening behavior and hardly any settlement. Considering both fluidity and settlement stability, APA
(ammonium-polyacrylate) was chosen as the dispersant to increase the solid volume fraction of ZrO2 suspension. Utilizing the above suspension, a kind of refractory nozzle for precision casting of a Cu-Cr alloy was prepared by gelcasting. Such nozzle has a very good resistance to thermal shock and flux scouring.
Plastic Forming of Zirconia from Coagulated Suspensions
Authors: Ye Hao , Liu Jia Chen , Feng Tie Cheng , Zhao Yu Hong , Min Jiang
Published: March 2009

A new method of plastic forming was carried out for zirconia ceramics, which was based on more uniformly mixed and de-agglomerated pastes produced by a process thatinitial dispersion of suspension and subsequent coagulated at a sufficient high solid loading. Through comparing of three approaches or conditions, our results proved that this plastic forming process can give rise to components of higher strength compared to those produced by existing processing route.
Microstructure of Environmental Barrier Mullite and Erbium Silicate Coatings on SiC-Fiber Bonded Composites
Authors: Khan Zuhair S. , Hinoki Tatsuya , Kohyama Akira
Published: March 2009

SiC-composites are candidate structural materials for high temperature applications such as gas turbines. For this purpose, a suitable coating against high temperature oxidation is essential. The coating material selection was made by phase stability/durability under service environment, CTE matching, low elastic modulus and chemical compatibility with SiC. This work is to evaluate the microstructural quality of mullite and erbium silicate coatings on SiC fiber bonded composites. In this work, SiC-fiber bonded 2D-composite (TyrannohexTM) by Ube Industries Ltd., were coated with mullite and erbium silicate by plasma spraying. The thickness of
mullite and erbium silicate coatings was determined to be 120 microns and 220 microns, respectively. The fabricated samples were diamond polished for cross-sectional analyses by optical and scanning electron microscopy.
The coating-substrate interfaces have been found bit undulating. The bonding between mullite and the substrate was found insufficient as compared to that observed in the erbium silicate coated substrate. The cross-sectional analyses of erbium silicate coating revealed the presence of throughthickness micro- and macro-cracks. The width of the macrocracks was found in the range of 1-3
microns. It is conceived that the evolution of large concentration of through-thickness-cracks is due to the stresses in the coating. The most probable sources of stresses are the precipitation of various second phases in the coating materials and the thermal expansion mismatches that arise during cooling. The mullite coating on the other hand is not found with macrocracks and on the whole the
cohesion within the mullite coating is rather strong. The cross-sectional examination also revealed the irregularly distributed pores and cavities in both coating systems that are typical of thermal sprayed coatings. The surfaces of the coatings are characterized of typical lamellar microstructure formed by the flattened platelets of individual particles. The size of these droplets ranges from submicrometer
to several micrometers.
Bending Strength of the Seeded and Tape Cast Si3N4 before and after Oxidation Exposure in Air at 1500°C
Authors: Zeng Yu Ping , Kondo Naoki , Hirao Kiyoshi , Kita Hideki , Ohji Tatsuki , Kanzaki Shuzo
Published: March 2009

Silicon nitride ceramics was prepared by tape casting nonaqueous ceramic slurries,
laminating the green ceramic tapes, and gas pressure sintering in nitrogen atmosphere. Lu2O3 and SiO2 were used as the sintering additives, and 3 wt.% β-Si3N4 seed was added to enhance β-Si3N4 grain growth unidirectionally. The seeded and tape-cast Si3N4 showed very good high temperature bending strength at 1500oC, when the stress applied along with the grain alignment direction. This
was attributable to the formation of a high melting point grain boundary phase and the fibrous Si3N4 grains alignment. After exposure in air at 1500oC for up to 100 h, the oxidation products formed on the Si3N4 surface consist of Lu2Si2O7 and SiO2. The bending strength of the oxidized and tape-cast Si3N4 was degradation, the strength decrease was associated with the formation of new defects on the surface and the interface between the oxide layer and the Si3N4 bulk.
The Recycled Aggregates with Surface Treatment by Pozzolanics
Authors: Kim Jae Jun , Youn Sang Heum , Cho M.J. , Shin H.T. , Yoon Jeong Bae , Hwang Kyu Hong , Lee D.S.
Published: March 2009

To improve the mechanical properties of concretes containing recycled aggregates, pozzolanic materials were used to decrease the porosity of the recycled aggregates. These pozzolanic materials were adhered on the surface of recycled aggregates and closed the open pores so that the water absorption was
decreased 1~2% as the amount of adsorption was increased. Compressive strength of cement mortars and concretes using surface treated recycled aggregates reaches above 95% of the strength of its natural counterparts. Investigation of the microstructures using the scanning electron micrographs showed the formation of dense interface after the adsorption treatment
of pozzolanics to recycled aggregates.
Development of the Reaction-Bonded Si/SiC Ceramic Tubes for High-Temperature Heat Exchangers
Authors: Han In Sub , Seo Doo Won , Lee Shi Woo , Hong Ki Seok , Woo Sang Kuk , Lee Kee Sung
Published: March 2009

The Ministry of Commerce, Industry and Energy has contracted with the KIER including the ceramics company to localize of the ceramic heat exchanger tubes and its components. The basic objective of this paper is to develop a ceramic formulation and process which would yield a cost-effective and long-life Si/SiC tube materials by extrusion and reaction sintering process. Thus,KIER is currently developed and localized heat exchanger tubes with 40mm out diameter, 1500mm length. This paper was tested the mechanical and thermal properties of the localized Si/SiC tubes obtained from reaction sintering. Also, the effect of energy savings of the heat exchanger after exposure to forging furnace with hot corrosive environment was investigated.
Preparation and Evaluation of 5-FU/PLGA/Gene Nanoparticles
Authors: Hu Yun Xiang , Chang Jin , Guo Yi , Yuan Xu Bo , Kang Chun Sheng , Pu Peiyu
Published: March 2009

In this study, we constructed a novel drug delivery system for realizing the combination of gene therapy and chemotherapy by co-loading 5-FU and antisense EGFR (epidermal growth factor receptor) plasmids in biodegradable PLGA/O-CMC (O-carboxmethyl-chitosan) nanoparticles. This novel kind of nanoparticle was characterized by dynamic light scattering for size, size distribution and zeta potential, and scanning electron microscopy (SEM) and transmission electronic microscopy (TEM) for morphological properties and structures. Drug encapsulation efficiency and drug release kinetics under in vitro conditions were also measured. At the same time, the MTT assay, the TUNEL technique and immunohistochemical staining were used to investigate the antitumor activity of these multi-functional nanoparticles on human glioma cells. It was concluded that the 5-FU and plasmid encapsulation efficiencies were as high as 94.5% and 95.7%, and the 5-FU release activity from nanoparticles could be sustained for as long as three weeks. Both the MTT assay and the TUNEL method illustrated that these multi-functional nanoparticles had cytotoxicities as high as 93.5% and could induce apoptosis in most glioma cells. Immunohistochemical staining proved that plasmids on the surface of nanoparticles could transfect gliomas cells, verified by a decline in the expression level of EGFR protein by the glioma cells. Therefore, this novel delivery system for drugs and genes provides another therapeutic pathway for cancer and needs further research.
Preparation of Bioactive Nanophase Titania Ceramics by Alkali-Heat Treatment
Authors: Yu Qi Feng , Yang Bang Cheng , Wu Yao , Zhang Xing Dong
Published: March 2009

In this study, alkali-heat treatment in NaOH solution and heat treatment, which could form amorphous sodium titanate on nanophase titania ceramics surface by conditioning the process, was employed to modify the structure and bioactivity of biomedical titania ceramics. After the nanophase titania ceramics was subjected to alkali-heat treatment, thin film X-ray diffraction and scanning electron microscopy results showed the titania ceramics surfaces were covered by porous sodium titanate. In fast calacification solution (FCS), the alkali-heat treated titania ceramics could induce bonelike apatite formation on its surface. Our results showed that induction of apatite-forming ability on titania ceramics could be attained by alkali-heat treatment. So it was an effective way to prepare bioactive titania ceramics by combining sintering and alkali-heat treatment.
Molecular Modification of Hydroxyapatite to Introduce Interfacial Bonding with Poly (Lactic Acid) in Biodegradable Composites
Authors: Zhang Sheng Min , Luo Qing Ming , Cao Rui Rui , Li Shi Pu
Published: March 2009

Six silane-modified hydroxyapatite (HA) / poly(lactic acid) (PLA) composites at 20% volume HA are prepared through absorption in liquid phase, volatilization, milling, and hot-press molding. Bending testing results indicate that their bending strengths are higher than that of control HA composite (unmodified HA composite) and the maximum strength enhances 27.8%. Calcium precipitation and calcium release experiments are designed to examine the bioactivity of the
modified HA. The results show that the presence of the modification coating does not really impair the bioactivity and mineralization tendency of HA particles. Relationship of swelling property of the composites as function of time is investigated. Swelling equilibriums of silane-modified HA / PLA composites are reached after 48 h or 72 h, but the equilibrium of the unmodified HA / PLA composite is reached within 24 h. The swelling experiment also suggests that the desired swelling property of the composites could be achieved by changing modification molecules of HA according to necessity. Finally, SEM micrographs show that there is an improved interfacial binding between the modified HA and PLA matrix.
Comparison in In Vitro Evaluation of Wollastonite and Dicalcium Silicate Coatings
Authors: Liu Xuan Yong , Ding Chuan Xian , Chu Paul K.
Published: March 2009

In-vitro evaluation of plasma sprayed wollastonite and dicalcium silicate coatings was carried out by SBF soaking test and osteoblasts seeding test. Apatite layers were formed on the surfaces of the two coatings indicative of the excellent bioactivity. The formation rate of apatite is higher on dicalcium silicate than on wollastonite. The cause is believed to be the presence of orthosilicate species in the dicalcium silicate coating promoting easier leaching by exchanging H3O+ ions from the solution with calcium ions concentrated in the orthosilicate positions. At the same time, loss of soluble silicon occurs, and it is supposed to enhance the repolymerization of the silica gel layer and provide the active sites for the nucleation of apatite. The outcome is that apatite forms faster on dicalcium silicate than on wollastonite. The data obtained from the osteoblasts seeding test indicate that the wollastonite and dicalcium silicate coatings promote the proliferation of osteoblasts and possess excellent biocompatibility.
PEG-Containing Polymeric Films and Gels as Postoperative Tissue Adhesion Barriers
Authors: Go A.K. , Kim J.K. , Oh Se Heang , Yuk Soon Hong , Lee Jin Ho
Published: March 2009

This study was designed to evaluate the effect of polyethylene glycol (PEG) and
nonsteroidal anti-inflammatory drug (ibuprofen) on the prevention of postoperative tissue adhesion. For this, we synthesized poly(L-lactic acid)-PEG diblock copolymers and used them to prepare ibuprofen-loaded films as tissue adhesion barrier films. We also prepared lower critical solution temperature (LCST)-controllable Pluronic F127/F68 mixtures including mildly crosslinked alginate and ibuprofen as tissue adhesion barrier gels. The prepared films and gels with/without ibuprofen were evaluated by the observations of peritoneal tissue adhesion via animal study using a rat model.
Surface Characterization and In Vitro Blood Compatibility of Poly(Ethylene Terephthalate) Immobilized with Hirudin
Authors: Li F. , Wang Jin , Sun H. , Huang Nan
Published: March 2009

Poly(ethylene terephthalate) films were exposed under argon plasma glow
discharge and induced polymerization of acrylic acid (AA) in order to introduce carboxylic acid group onto PET (PET-AA) assisting by ultroviolet radiation. Hirudin-immobilized PETs were prepared by the grafting of PET-AA, followed by chemical reaction with hirudin. The surface structure of the treated PET is determined by X-ray photoelectron spectroscopy (XPS). The wettability and surface free energy, interface free energy of the films is investigated by contact angle measurement. Platelet adhesion evaluatiion is conducted to examine the blood compatibility in vitro. Scanning electron microscopy (SEM) and optical microscopy reveal that the amounts of adhered, aggregated and morphologically changed platelets are reduced on hirudin-immobilized PET films.
New Method for Evaluating Material Blood Compatibility Using Microchannel Array
Authors: Kurotobi K. , Yamamoto Akiko , Kikuta A. , Hanawa Takao
Published: March 2009

Microchannel array chips modified by metal deposition or polymer coating were
contacted with blood. Titanium (Ti), chromium (Cr) and gold (Au) films were deposited onto the microchannel array chips. Albumin (Alb) and MPC polymer (MPC) were coated onto other chips. Non-treated Si chips were used as a control. Whole blood was collected with 1000 units/ml heparin solution from young healthy volunteers. The passing time of a 100 µl portion of human whole blood
through these channels was measured under a pressure difference of 20 cm H2O. Simultaneously, the flow behavior of blood cells in channel was observed by an optical microscope and recorded by a video recorder. Platelet adhesion was observed on Si, Ti, Cr, and especially on Au. The blood pass-through time (BPT) increased in order of Ti, Si, Cr and Au. On the Alb- and MPC-coated chips, platelets were seldom observed and the BPTs were short in comparison with the metal chips. From these consequences, platelet adhesion depended on the materials. The BPT correlated well to the number of adherent platelets on the materials. Therefore, the blood coagulation reaction originated in platelet activation could be detected using microchannel array. We concluded that this method could be applied to evaluate initial blood compatibility of materials within several minutes in vitro.
In Vitro Dissolution Behavior of Gel-Derived Bioactive Glasses in the SiO2-CaO-P2O5-MgO System
Authors: Cai Yurong , Zhou Lian , Wei Jian Hua , Yu Zhen Tao , Niu Jin Long
Published: March 2009

Bioactive glass-ceramics of the SiO2-CaO-P2O5-MgO system were fabricated by sol-gel-self propagating method. Two Gel-derived materials discs， 5S and 3S， were prepared by compression of powders. The materials obtained were examined in vitro with regard to the dissolution behavior and the formation ability of calcium phosphate layer on the surfaces of samples in simulated body fluid (SBF). Concentration of ions and pH value in SBF were determined by ICP-AES and micro acidity meter after 3S and 5S were immerged in SBF for intervals from 6h to 15 days and the surface characteristic of 3S and 5S soaked were determined by SEM. Experiment results showed that the formation ability of calcium phosphate on the surface of gel-derived materials depended on the speed of dissolution of samples, which related to original chemical composition and size of crystal on the surface of materials. With decreasing of Si content and increasing of Ca content, smaller crystal could be formed on the surface of 3S, which tended to dissolve more quickly in SBF. Solubility product of calcium phosphate can be reached more easily in the solution with high concentration of Ca and P and bone-like carbonate apatite formed easily on the surface of 3S.
Effect of Indenter Materials on Indentation Fracture of Alumina Ceramics
Authors: Usami Hatsuhiko , Kadomae Tomoya , Igimi Daisuke , Mizuno Mineo
Published: March 2009

The present study describes the effect of indenter materials on Hertzian cracking
behavior of alumina ceramics in sphere indentation. Numerical analysis (FEM) was carried out to investigate the influence of the frictional resistance at the interface due to the elastic mismatch between the indenter and the flat specimen on the stress distribution near the contact area. Two kinds of alumina ceramics with different mechanical properties were used for the flat specimen. Materials of the sphere indenter were cemented carbide, silicon nitride, alumina and hardened steel.
The indenter was penetrated into the specimen with an electro-mechanical testing apparatus at a constant cross-head-speed in air. The indentation fracture was monitored with the acoustic emission signal. The numerical analysis revealed that the frictional resistance had influenced on the stress distribution. The experimental data showed that the ring crack radius, the crack pass below the contact zone and the indentation strength were different depending on the indenter material. From the comparison between the numerical analysis and the experimental data, it was found that the minimum value of the ring crack radius of the low density alumina flat specimen corresponds to the position of the maximum tensile stress.
Trends in Fluid Application Strategy for Grinding Processes
Authors: Stephenson D.J.
Published: March 2009

The current application of fluids in grinding processes is discussed, the issues related to the use of both mineral oil and water based fluids and the desire to move towards minimum quantity lubrication (MQL) or even dry grinding. The impact of fluid application strategy on workpiece quality is considered. In particular the importance of reliable thermal modelling and knowledge of the thermal partitioning of heat is essential if robust fluid application strategies are to be developed. Examples are given showing how an understanding of the thermal characteristics of the process can be used to develop different and successful fluid application strategies for various grinding regimes from creep feed through to high efficiency deep grinding (HEDG). The possibility of using solid lubricants is also discussed for particular grinding regimes.
Improvement of Surface Texture of Stainless Steel by Utilizing Dry Blasting - 2nd Report: Effect of Blasting Conditions on Wettability -
Authors: Minaki Kazushi , Kitajima Koichi , Minaki K. , Izawa Moriyasu , Tosha Katsuji
Published: March 2009

Recently, wet blasting is generally used such as liquid honing and water jet machining in surface before plating of stainless steel. The outstanding feature of wet blasting is to prevent generation of static electric charge, to use micro abrasive grain, and to have cushioning for workpiece. On the other hand, the disadvantage of wet blasting is to generate corrosion of equipment and liquid waste under processing. Moreover, the using abrasive grain is available on a limited basis. In particular, improvement disposal of liquid waste under processing is crucial in the near future. This paper makes proposal for improvement of surface texture by utilizing dry blasting, and it conducts improvement of surface texture about martensite stainless steel (SUS420J2 In JIS), which is used in material for scale applications. As a result, it is cleared that relationship between surface texture and blasting conditions. Furthermore, based on these results, it reports relationship between surface texture and wettability.
Development of Gas-Atomized Magnetic Tools
Authors: Saito T. , Koike K. , Yamato H. , Kuwana A. , Suzuki A. , Yamaguchi H. , Shinmura Takeo
Published: March 2009

The deficiency in the variety of available magnetic abrasive results in a narrow range of finishing performance. To break through this difficulty, this research developed iron-based gas-atomized magnetic tools. The magnetic tool has a spherical shape and micro-crevices on the surface. The micro-crevices perform the role of cutting instead of the edges of the existing magnetic abrasive, thereby achieving abrasive-less finishing. This paper studies the finishing performance of
the developed magnetic tool. Compared to the existing magnetic abrasive, this magnetic tool shows more efficient finishing performance in the internal finishing of SUS304 stainless steel tubes used for sanitary piping systems.
High-Speed Milling Experiments on the Extended Length of Milling Tool
Authors: Qin Zhe , Wang Cheng Yong , Hu Ying Ning , Lin Y.S.
Published: March 2009

High speed milling is widely employed in die and mold machining, and the attentions
had been gradually paid on the details during the process. Based on the high-speed milling experiments of hardened steel with different extended length of tool, cutting force, cutting vibration, tool wear and surface roughness were measured and analyzed in this paper. It was founded that cutting force and vibration were not increasing straightly with the addition of extended length, but fell down when exceeded a certain value, and the surface quality improved at same time.
New Compensation Grinding of Axisymmetric Aspherical Lenses with High NA Value
Authors: Yoshihara Nobuhito , Kuriyagawa Tsunemoto
Published: March 2009

Aspherical parts are installed in various optical instruments. At present, a higher form
accuracy is required for aspherical parts to improve the resolution of the optical instruments. To meet this demand, an arc envelope grinding method has been developed. In the arc envelope grinding process, a spherical shaped grinding wheel is used and the form error of the cross-sectional profile of the grinding wheel is transcribed to the workpiece profile. Therefore, the grinding wheel should be trued previously. However, the form error of the grinding wheel cannot be removed perfectly. To reduce the affect of the form error of the grinding wheel, compensation grinding must be carried out. In this work, the wheel path of a new compensation grinding method is proposed for a high NA value of the workpiece. Tests using the new compensation grinding method demonstrate the reduction in the form error of aspherical parts.