bluuebunny/crossref_metadata_2025 huggingface dataset:
New Material of Ni-Ti Alloy for Chip Tantalum Capacitor Fuse
Authors: Liu Yang , Wang Yan , Ma Ju Sheng
Published: March 2009

With the wide application of SMT, mass chip components have been applied including tantalum capacitor. A fuse buried in a capacitor can protect the whole system of merit. In the paper a titanium nickel alloy with vanadium addition has been developed as a fuse material. Several alloy wires with different diameters have been used in the fusing experiment. The influencing factor have been discussed that a few factors including diameter, chucking and so on affect the fusing current. Analyses on the fuse wires have been investigated with SEM, XRF and XRD to measure the composition of alloy wires.
Simulation and Fabrication of Silicon Micro-Grippers Actuated by Piezoelectric Actuator
Authors: Kim Won-Hyo , Park Joon Shik , Shin Kyu Shik , Park Kwang Bum , Seong Woo Kyeong , Moon Chan Woo
Published: March 2009

The eight types of micro-grippers with silicon were simulated by ANSYS and fabricated by MEMS(Micro Electro Mechanical System) process. Each type of micro-grippers had a small difference in design shape such as beam width, gap between beams. In order to modify design shape, these micro-grippers were estimated and simulated in point of structure, actuation characteristics by changing design factors. Micro-grippers were composed of five parts which were piezoelectric actuation part, fixing part, rotation arms, the block and gripping jaws. The shape of gripping jaws was designed as the teeth of a saw to reduce adhesion force by decreasing the contact area. The 10.2 µm movement by piezoelectric actuator at 120 V generated the 142.8 µm gripping range of a micro-gripper in real measurement. In the case of simulation result, the gripping range of 162 µm was generated at the same condition. This gripping range was enough to handle small objects like micro-parts
Metal-Containing Diamond-Like Nanocomposite Thin Film for Advanced Temperature Sensors
Authors: Takeno T. , Takagi Toshiyuki , Bozhko Aleksandra A. , Shupegin M. , Sato T.
Published: March 2009

The conductivity of metal-carbon-silicon nanocomposite films considered as potential
candidates for the application as wide-range temperature sensors for severe environmental conditions is studied. The films combine unique properties of amorphous carbons with a new functionality imparted by the presence of metal nanoclusters in host matrix. The deposition of carbon-silicon phase was performed using PECVD of siloxane vapors. Metals (W, Nb, and Cr) with concentration in the range from 12 to 40 at. % were incorporated in the carbon-silicon host matrix by DC magnetron co-sputtering. The conductivity of the films decreases with temperature in the range 80-400 K, being well described by the power-law dependence. The conductivity mechanism found satisfactory explanation in the framework of the model of inelastic tunneling of electrons between metal nanoclusters dispersed in carbon-silicon matrix. The parallel study of the influence of metal concentration increase on carbon phase microstructure was carried out using Raman spectroscopy.
Study on Magnetoresistance for Trilayer with Fe3O4 Film
Authors: Kida Ayumu , Kodera Kazushi , Ohmori Kazuhiko , Asano Hidefumi , Matsui Masaaki
Published: March 2009

High quality Fe3O4 thin film was synthesized by the magnetron sputtering method using Ar-H2 gas. Giant magneto resistance of the trilayer using Fe3O4 was investigated, where the observed MR ratio was less than 1%. A phenomenological calculation was made to make the origin of the small MR ratio clear, using a parallel current model assuming five passes. It is concluded that the non-magnetic layer surrounded by two magnetic layers is necessary to have the same order resistivity and similar thickness with Fe3O4 layer in order to obtain the large MR ratio for the
trilayer using Fe3O4.
An Improvement in Sintering Property of β-Tricalcium Phosphate by Addition of Calcium Pyrophosphate and Calcium Carbonate
Authors: Wang Xin Long , Fan Hong Song , Zhang Xing Dong
Published: March 2009

b-tricalcium phosphate(TCP, Ca3(PO4)2) ceramics are preferred as a bioceramics because of its chemical stability and reasonable degradation rate in vivo, but it is difficult to obtain b-TCP ceramics with high compressive strength at lower temperature than that of phase transition to a-TCP. In this study, the sintering behavior of TCP, Ca2P2O7-doped TCP, and CaCO3-doped TCP in the range of 2wt%~5wt% were investigated respectively. Phase transition of pure TCP took place between 1100°C to 1150°C, and pure b-TCP ceramics could achieve a
compressive strength of only 3MPa. However, calcium pyrophosphate (CPP, Ca2P2O7) additive prevented the transformation of b-TCP to a-TCP, but the second phase of CPP was observed in the resultant ceramics. Phase transition of TCP ceramics by addition of both CPP and calcium carbonate (CC, CaCO3) took place between 1200°C to 1250°C and the resultant TCP ceramics had few impurity of CPP. By adding CPP and CC to TCP, final ceramics with compressive strength over 12MPa could be obtained when sintered at 1200°C for 2hrs.
Effect of Alloying Elements on the Strength and Casting Characteristics of High Strength Al-Zn-Mg-Cu Alloys
Authors: Kim Ki Tae , Kim Jeong Min , Sung Ki Dug , Jun Joong Hwan , Jung Woon Jae
Published: March 2009

Small amounts of various alloying elements were added to a high strength Al-Zn-Mg-Cu alloy and their effects on the microstructure, mechanical properties, and casting characteristics were investigated. Silicon additions with or without extra Mg to the Al-Zn-Mg-Cu alloy could enhance the castability such as fluidity, feedability, and hot tearing resistance significantly while maintaining a high strength. However, in these alloys containing silicon the compositional adjustment was necessary to prevent the Mg2Si phase formation from degrading the precipitation of MgZn2 phase that is responsible for the high strength. Zr addition to the base alloy was also observed to improve the feedability without deteriorating the tensile strength.
Influence of Sintering Temperature on Mechanical Properties of Ti-6Al-4V Compacts by Metal Injection Molding
Authors: Guo Shi Bo , Qu Xuan Hui , He Xin Bo
Published: March 2009

Titanium and titanium alloys have low density, high strength, excellent corrosion resistance in many media and are known to be biocompatible. This combination of properties makes titanium and its alloys an excellent choice for the applications, such as watch parts, medical devices, dental parts and sports goods. However, in the respect of fabricating complicated shaped parts, low machinability may be a barrier to practical uses. Therefore, it is considered to be very available that metal injection molding(MIM) process is applied to fabricate titanium alloy parts[1-2].
Nevertheless, injection molding of titanium and its alloys presents a real challenge to the processor due to its reactivity. Titanium not only has a strong affinity to oxygen, but also tends to react readily with carbon, nitrogen or hydrogen from the furnace atmosphere. Therefore, contamination by interstitial light elements such as oxygen and carbon is a serious problem because they have much influence on the mechanical properties of titanium alloys[3-5]. So it is necessary to control debinding and sintering conditions. In this paper, preparation of Ti-6Al-4V compacts was performed by MIM process. To reduce the contamination, the debound compacts were sintered at moderate temperature range from 1170°C to 1320°C and high vacuum (10-3Pa). On these conditions, the mechanical properties and relative
density of sintered compacts were investigated.
Microstructural Evolution of Undercooled Ni-40wt%Pb Hypermonotectic Alloy
Authors: Zheng Hong Xing , Yu Yun , Li Jian Guo
Published: March 2009

Microstructural evolution of bulk undercooled Ni-40wt%Pb hypermonotectic alloy was systematically investigated by using molten glass purification and superheating cycling. Within the achieved undercooling range, the microstructures were classified into three categories. When the undercooling was less than 50K, the microstructure consisted of coarse dendritic grain and interdendritic Pb lumps. Increasing undercooling to the range 100 to 198K, macrosegregation was serious. When the undercooling was up to 292K, refined granular grain with homogeneously distributed fine Pb particles on it formed. The granulation mechanism of granular grains was owing to dendritic disintegration and subsequent recrystallization.
Effect of State of Stress on the Cavitation Behavior of Al 5083 Superplastic Material
Authors: Chandra Names , Khraisheh Marwan K. , Kalu Peter N.
Published: March 2009

In this paper we address the controversial issue of nucleation of cavities in Al 5083 alloys and their subsequent growth to coalescence and failure. We focus on the origin and growth of cavities not only during the primary processing of Al 5083 in sheet forms, but also during the manufacture of these sheets into SPF (superplastic forming) components. Experimental observations of pre-existing
cavities in this alloy are made using optical and electron microscopy. The role of sheet rolling direction, and the state of stress during superplastic deformation on the cavity formation and coalescence are also discussed. The effect of the state of stress (uniaxial, plane strain, balanced biaxial, and tri-axial) on the growth characteristics of cavitation is also examined. It is found that the uniaxial model based cavitation cannot directly be extended to predict the behavior of more complex stress states, unless great care is taken to identify the right strain measure for the mapping process.
Superplastic Forming of Aluminum Alloy Car Body Panels
Authors: Zeng Zhi Peng , Zhang Yan Shu , Zhou Yi , Jin Quan Lin
Published: March 2009

An experimental study on superplastic forming of a front fender of 5182 aluminum alloy is presented in this paper. Based on the shape characters of the front fender and the material experimental results, dies, heater and temperature controller for superplastic forming of the fender are designed and manufactured. The SPF results show the designed processing and dies are reasonable and feasible.
Application of Superplastic Forming and Diffusion Bonding in the Aerospace Industry
Authors: Li Zhi Qiang , Guo He Ping
Published: March 2009

As a versatile fabrication process for titanium and aluminum alloys, SPF/DB offers a real potential for revolutionizing aerospace component design. In this paper, the principle, advantages, techno-economics of the process, as well as its application in aerospace industry are introduced. The current trends and the factors relating to the process’s developments are given.
Finite Element Simulation and Experimental Research on the Internal Rolling Connection for Titanium Alloy Tubes
Authors: Zeng Yuan Song
Published: March 2009

In this paper, the internal rolling process is presented to connect the titanium tubes to the tube fitting with the mechanical method. The material flow, the distribution of stress and strain and the connecting mechanics are analyzed by using the finite element method(FEM) for two kinds of the tube fitting structures, the triangle grooves and the rectangle grooves. Rolling experiments and tests for pressure durability, gas-sealing ability, surface finish and contact percent are also
introduced. Results show that the tube joints with the triangle grooves has very excellent connecting strength, and the FE analysis agrees well with the experiments.
High Speed Roll Casting of Aluminum Alloy Strip
Authors: Nakamura Ryoji , Watari Hisaki , Kumai Shinji
Published: March 2009

Two kinds of roll casters, which were suitable for high speed roll casting, were devised. One was a vertical type twin roll caster, and the other was an unequal diameter twin roll caster. The semisolid roll casting using a cooling slope was adopted to these roll casters. The solid fraction was smaller than 5%. 3 mm thickness of 6111 strip was cast at 60 m/min by the vertical type twin roll caster, and 5 mm thickness of 6111 strip was cast at 30 m/min by the unequal diameter twin roll caster. The microstructure of the as-cast strip was equiaxed and spherical, not columnar. The mechanical properties of the strip rolled from roll-cast strip were almost as same as that of the strip made from cast ingot.
The Growth of GaN Films on Si Substrates by HVPE
Authors: Yu Huiqiang , Chen Lin , Zhang Rong , Xiu Xiang Qian , Xie Zi Li , Ye Yu Da , Gu Shu Lin , Shen Bo , Shi Yi , Zheng You Dou
Published: March 2009

GaN films are grown on Si(111) with low-temperature GaN (LT-GaN) layers as buffer layers by hydride vapor phase epitaxy (HVPE). The LT-GaN layers are deposited at different temperatures ranging from 400 to 900 °C. The surface property, the structure and optical properties of the GaN films with different LT-GaN layers are studied. When deposition temperature of LT-GaN layer is 600 °C, the GaN film shows the best properties.
Hydrophilic Properties of TiO2-Al2O3 Composite Thin Films
Authors: Liu Qing Ju , Zhang Jin , Zhu Zhongqi , Jin Yingxia , Wang Qing Hui
Published: March 2009

TiO2-Al2O3 composite thin films were fabricated on soda-lime glass with sol-gel
technology. By measuring the contact angle of water with the film surface and the analysis of the XRD and XPS, we studied the influence of Al2O3 doping concentration and film thickness on the hydrophilicity of the composite films. The results indicate that the doping of Al2O3 into TiO2 and the relatively large thickness of the films can improve their hydrophilicity.
High Quality Ceramic Coatings Sprayed by High Efficiency Hypersonic Plasma Spraying Gun
Authors: Zhu Sheng , Xu Bin Shi , Yao Jiu Kun
Published: March 2009

This paper introduced the structure of the high efficiency hypersonic plasma spraying gun and the effects of hypersonic plasma jet on the sprayed particles. The optimised spraying process parameters for several ceramic powders such as Al2O3, Cr2O3, ZrO2, Cr3C2 and Co-WC were listed. The properties and microstructure of the sprayed ceramic coatings were investigated. Nano Al2O3-TiO2 ceramic coating sprayed by using the high efficiency hypersonic plasma spraying was also studied. Compared with the conventional air plasma spraying, high efficiency hypersonic plasma spraying improves greatly the ceramic coatings quality but at low cost.
Synthesis of Perovskite-Type LaMnO3 under Hydrothermal Conditions
Authors: Feng Cai Hong , Li Qian Shu , Liu Chen Min , Deng Yuan , Guo Lin
Published: March 2009

The precursor of LaMnO3 obtained by the reaction of metal salt with potassium
hydroxide was subjected to hydrothermal condition in an autoclave then the precipitate was treated in different temperatures (600-900°C). The effect of precursor type and hydrothermal crystallization conditions on the morphology of lanthanide manganese grains was investigated. The morphology and the structure of the products was studied by transmission electron microscope (TEM) and X-ray diffraction (XRD). Different shapes of LaMnO3 can be obtained by controlling prepare condition and treated temperature. The XRD results showed the formation of perovskite-type LaMnO3.
Effects of Hydrogen on Tensile Properties of SA508 Cl.3 Reactor Pressure Vessel Steel at High Temperature
Authors: Cho Hyun Chul , Kim In Sup
Published: March 2009

Tensile properties of SA508 Cl.3 reactor pressure vessel (RPV) steel were investigated at room temperature and at 288 °C before and after hydrogen charging by electrolysis. At room temperature, the charged hydrogen induced distinct hardening and ductility loss, where quasi-cleavage features were observed around inclusions. These results may be due to interactions between the dissolved hydrogen and dislocations and an increase of hydrogen concentration near the
inclusions. On the other hand, at 288 °C, the charged hydrogen induced some softening, which was explained in terms of the hydrogen shielding effect, and of strain localization by dynamic strain aging (DSA). Further, at 288 °C, the fracture surfaces of the hydrogen-charged specimens showed brittle regions, where the hydrogen might have been trapped in microvoids, leading to internal pressurization.
Iron–Aluminium-Base Alloys with Strengthening Laves Phase for Structural Applications at High Temperatures
Authors: Risanti D.D. , Sauthoff G.
Published: March 2009

Fe-Al-Ta alloys with the ternary Laves phase Ta(Fe0.5+x, Al0.5-x)2 are studied
experimentally with the objective of clarifying the effect of Laves phase precipitation and atomic ordering on the deformation characteristics of such Fe-Al-base alloys. The present study concentrates on the hardening effect of the Laves phase in ordered and disordered Fe-Al-Ta alloys with Al contents between 16 and 45 at.% showing the A2 disorder or the DO3 or B2 order. Ta has a low solubility in Fe-Al alloys which is beneficial for slowing down precipitate coarsening. Small amounts of Laves phase together with atomic ordering increase the yield stress and affect ductility in a complex way. The alloys with 1% Ta exhibit a high oxidation resistance. The continuing work aims at adjusting the Al and Ta content for an optimum relation of high-temperature strength and low-temperature ductility with maintaining a sufficient oxidation resistance.
Ultraviolet Induced Thermoluminescence in Gadolinium-Doped Zirconium Oxide Films
Authors: Azorín J. , Rivera T. , Furetta C. , Sánchez-Rodríguez A.
Published: March 2009

This paper presents the results of studying the thermoluminescent (TL) characteristics of Gadolinium-doped Zirconium oxide (ZrO2:Gd) films. Samples were prepared by the spray pyrolisis method depositing them on different
substrates using various concentrations of the dopant and exposing to UV radiation of different wavelengths in the range from 200 to 330 nm. Optimum concentration of the dopant determined on the base of maximum TL response was 12% when films were exposed to 260 nm UV light. At these conditions, ZrO2:Gd films presented a glow curve exhibiting two peaks at 110°C and 290°C, a broad range linear TL response as a function of spectral irradiance and a fading of the order of 11% in a week. No significant differences were observed in the TL characteristics of the films deposited on quartz or glass substrates. These results suggest that ZrO2:Gd films could be used in UV radiation measurement.
Silicon Oxynitride ECR-PECVD Films for Integrated Optics
Authors: Pernas P.L. , Ruiz E. , Garrido J. , Piqueras J. , Paszti F. , Climent-Font A. , Lifante G. , Cantelar E.
Published: March 2009

In this work we present results of Si/SiO2/SiON/SiO2 waveguides fabricated by means of ECR-PECVD. In order to change refraction index and simultaneously to reduce losses related with hydrogen, we have used N2 as precursor gas for controlling the nitrogen to oxygen relation present in the samples. The composition of the samples were carefully controlled by RBS and ERDA analysis. The refractive index and thickness were measured by using a prisma coupler method at a wavelength of 632.8 nm.
Radiation-Induced-Defects Localization in Single-Mode Optical Fibers
Authors: Girard Sylvain , Boukenter A. , Ouerdane Y. , Meunier J.-P.
Published: March 2009

We studied the defects at the origins of the permanent radiation-induced attenuation in four g-rays irradiated single-mode germanosilicate optical fibers (~1 MeV; 1.2 kGy; 0.3 Gy/s) in the spectral range 400 - 1700 nm. We determined the wavelength dependence of the following cladding codopant influences: germanium (0.3 %), phosphorus (0.3 %), fluorine (0.3 %) on the germanosilicate (13 %) fiber radiation responses. We identified some of the different color centers produced by g-rays and we evaluated their localization in the fiber cross-section through the determination of the radial distribution of the radiation-induced absorption at 633 nm. We also evidenced the strong interactions between these three codopants. In particular, our results showed that the properties of the phosphorus-related color centers, which mainly determine the fiber infrared radiation sensitivity, are strongly influenced by the germanium- and fluorine-codoping.
Endohedral Encapsulation of Lithium in C70
Authors: Veljković M. , Nešković O. , Ivetić Tamara , Veličković S. , Maksin Tatjana
Published: March 2009

A new diatomic molecule-containing endohedral fullerenes were prepared by ion implantation technique (introducing negatively charged C70 into a low temperature lithium plasma column by a strong exial magnetic field).The species prepared were Li@C70 and Li2@C70 and ionized by surface ionization. Their existance was demonstrated through high sensitivity, magnetic mass spectrometer. The corresponding endohedral ions undergo the Rice shrinkwrap mechanism: a mass –analyzed ion spectrum demonstrates the loss of a C2 unit from the cage. The observed ionization energies of endohedral molecules were 5.1 " 0.1 eV and 5.3 " 0.1 eV, respectively.
Study of the Isotope Effects in the Hydrogen Transport in Polycrystalline Tungsten
Authors: Esteban G.A. , Perujo A. , Legarda F.
Published: March 2009

A time-dependent gas-phase isovolumetric desorption technique has been used to evaluate the diffusive transport parameters of hydrogen isotopes in polycrystalline tungsten in the temperatures range 673 to 1073 K and driving pressures from 1.3 104 to 105 Pa. Experiments have been run with both protium and deuterium obtaining their respective transport parameters diffusivity (D), Sieverts’ constant (Ks), the trap site density (Nt) and the trapping activation energy (Et). Isotope effects on these transport parameters are analysed and modelled. Because the classical isotope relation for diffusivity has not been fulfilled, quantum-statistical vibration theory has been applied to model the isotopic relation. A congruent isotopic variation of diffusion parameters related to the type of microstructure, bcc, has been confirmed.
Sliding Wear Behavior of Steam Generator Tube Materials in Nuclear Power Plants
Authors: Kim Gyung Guk , Kim Ji Hui , Lee Kwon Yeong , Kim Seon Jin , Lee Deok Hyun , Hur Do Haeng , Choi Myung Sik , Han Jung Ho
Published: March 2009

Wear damage of steam generator tubes of nuclear power plants can cause leakage of radioactive substances. So the evaluation of tubes’ integrity is very important from the viewpoint of nuclear ecocide. In the present study, sliding wear behaviors of Inconel 600 and 690 steam generator tube materials mated with 409 stainless steel commonly used as the support plate were investigated at room temperature in an air environment. For more precise prediction of wear behaviors of steam generator tubes, Archard equation was modified, and the modified wear
coefficients were estimated as a function of sliding distance. When using the modified Archard equation, the reliabilities for prediction of wear behavior of Inconel 600 and 690 mated with 409 stainless steel increased from 71.8% to 83.8% and from 60.2% to 85.2%, respectively.
Mechanical and Wear Properties of Silicon Nitride Added with AlN
Authors: Sung Rak Joo , Kim Seung Ho , Kusunose Takafumi , Nakayama Tadachika , Sekino Tohru , Niihara Koichi
Published: March 2009

Silicon nitride with various amount of AlN as a sintering aid was sintered by a hot
press method. Densified silicon nitrides were obtained, and it was found that the mechanical and wear properties were dependent on the contents of AlN. The effect of a/b phase on the mechanical and wear properties of silicon nitride was investigated. The properties were changed depending on the amount of a/b phase. In the brittle materials, tribological behaviors were dependent on the microstructure as well as hardness and fracture toughness. We focus on the relationship between the microstructure and mechanical/wear properties of silicon nitride
including AlN additives.
Analysis of Pipe Flow during Transportation of Magnesium Alloy Melt
Authors: Lee Hwang Gu , Kim Dong Jin , Han Jeong Whan , You Byung Don , Byun Ji Young
Published: March 2009

Magnesium alloys have been well known as active metals. Thus, magnesium alloys in molten state must be handled with extreme care during melting and casting. In this study, water model experiments and numerical analyses were carried out to optimize a pipe flow that can transport magnesium alloys in molten state safely from melting to casting furnace. Especially, during a transportation of molten magnesium alloys, a flow pattern in a pipe becomes important, because the interface between air and melt can be the source of the metal oxidation, and therefore, an air/melt interface area must be minimized. For these purposes, two vessels connected with a long pipe having two elbows with different diameters and radii of the curvature were simulated as melting and casting furnace for magnesium alloys. Optimized conditions with minimized air/melt interface area for the melt transportation were discussed in several pipe configurations.
Equilibrium and Metastable Eutectics Near the Ni3Al Composition
Authors: Lu Y. , Lee J.S. , Lee Je Hyun , Wee Dang Moon , Oh Myung Hoon
Published: March 2009

Ni3Al has been considerable research area due to its high temperature behavior increasing strength with increasing temperature. A series of directional solidification studies showed that the eutectic occurred between g’/b and the metastable eutectic of g/b forms under slightly different conditions, however, it is not well established whether the eutectic is composed of g/g‘, g’/b, or g/b .
In order to understand solidification behavior of the eutectic structure, directional solidification experiments have been carried out with solidification rate near the Ni3Al composition in this study. The effects of the solidification rate and composition on formation of the equilibrium and metastable eutectics have been discussed. The (g’+g) coupled phase was also shown to form with the eutectic at the solid/liquid interface.
The Combustion Characteristics of Refuse Derived Fuels Using Coke/Waste Tire
Authors: Park Myung Ho , Shin Dae Yong
Published: March 2009

Today every nation faces serious problems of energy supply. Reasonable technologies to make use of coal (including coke) can not only help the mining-related economy which is showing a downward trend but also may fit in with the governmental energy policy. In this research, we aim to supply heating systems in factories, homes, and farms with a substitute fuel by developing coke/waste tire compound fuel with high efficiency for rational use of energy and for recycling of
industrial products. A coke/waste boiler was used for this experiment, and different kinds of fuel were experimented including coke, waste tire, coke/waste A and coke/waste B. Four kinds of exhaust gas were also sampled by a gas analyzer, including CO, CO2, NO and NO2 at different temperatures.
Growth Kinetics of Intermetallic Compound and Interfacial Reactions in Pb-Free Flip Chip Solder Bump during Solid State Isothermal Aging
Authors: Kim Dae Gon , Jang Hyung Sun , Kim Young Jig , Jung Seung Boo
Published: March 2009

In the present work, the growth kinetics of intermetallic compound layer formed in
Sn-3.5Ag flip chip solder joints by solid-state isothermal aging was examined at temperatures between 80 and 150 °C for 0 to 60 days. The bumping for the flip chip devices was performed using an electroless under bump metallization. The quantitative analyses were performed on the intermetallic compound layer thickness as a function of aging time and aging temperature. The layer growth of the
Ni3Sn4 intermetallic compound followed a parabolic law within a given temperature range. As a whole, because the value of the time exponent (n) is approximately equal to 0.5, the layer growth of the intermetallic compound was mainly controlled by diffusion mechanism in the temperature range studied. The apparent activation energy of the Ni3Sn4 intermetallic was 49.63 kJ/mol.
Application of a Cold ECAP to Magnesium Alloy (AZ31) by a Combination of Extrusion Process
Authors: Song Jae Wan , Lim Hee Taek , Han Jeong Whan , Kim Mok Soon , Hwang Sun Keun
Published: March 2009

It is well known that magnesium alloys have difficulties in room temperature formability because of their HCP structure. As a basic approach to enhance a cold formability, a new combination process including an extrusion followed by a cold equal channel angular pressing (ECAP) was attempted. ECAP die has an inner die corner angle of 135 degree, the fillet angle of 45 degree and thickness of 5mm. A finite element analysis with a three-dimensional thermo-coupled elasto-plastic
model was also carried out to understand the change of stress and strain during ECAP. Experiments showed that the AZ31 alloy, which is extruded at a ratio of 20 and is heat-treated at 350°C, was successful in a cold ECAP. From the simulated results, it was found that the effective strain gradually decreased from the inner die side (0.533) to the outer die side. This was confirmed by the analytical
analysis via von Mises criterion. Furthermore, it also matched well with the experiments, which showed a uniform shear deformation band. It was also interesting to note that compressive yield strength was drastically increased, which is caused by the occurrence of numerous twins spread across the materials during a cold ECAP.
Mechanical and Electrical Properties of Y-TZP Containing TiNi-Base Intermetallic Compounds
Authors: Tanaka Norihito , Sekino Tohru , Nakayama Tadachika , Hayashi Yamato , Kusunose Takafumi , Niihara Koichi
Published: March 2009

Y-TZP/TiNi composites were successfully fabricated by reductive sintering process. Mechanical properties of Y-TZP / TiNi composites were much higher than those of Y-TZP monolith. XRD analysis revealed that TiNi-base intermetallic compounds such as Ni4Ti3, NiTi, Ni3Ti had been formed. Moreover, the electrical resistivity characteristics indicated that Y-TZP/TiNi composites
were a good conductor of the electricity.
Heavy Metal Leaching Behavior of Glasses Containing EAF Dust
Authors: Eun Hee Tai , Kang Seung Gu , Kim Yoo Taek , Lee Gi Kang , Kim Jung Hwan
Published: March 2009

Stabilizing characteristics of heavy metals in the silicate glass (SD) and lead silicate glass(PD) containing Electric Arc Furnace(EAF) dust was studied by the toxic characterization leaching procedure(TCLP) test. Dependence of the amount of EAF dust upon structural changes of SD and PD glasses and TCLP results was also investigated by FT-IR spectroscopy. In the TCLP test,
the concentration of heavy metals leached from a glass increased with the amount of EAF dust added. The SD series specimens showed heavy metal leaching lower than the PD series specimens, but the Pb leaching from the PD series specimens was the highest owing to the high Pb content in the PD glass composition. The value R(oxygen/network former ion ratio) was used to compare the leaching
characteristics of glasses, and the SD had a higer R than PD series specimens to show a better chemical durability. Adding the EAF dust to the SD mother glass decreased the Si-O-Si symmetry and increased the non-bridging oxygen, which weakened the structure and decreased the chemical durability of glasses. It is concluded that SD is more effective in stabilizing the heavy metals of EAF
dust than PD series glass.
Petroleum Separation through Polymer Blend Membranes Using Pervaporation
Authors: Huh Hoon , Rhim Ji Won , Park Ji Soon , Nam Sang Yong
Published: March 2009

Utilization of membrane offers the promise of huge energy savings if successfully applied to petroleum separations. Membranes are bound to enter into refining petroleum operations involving liquid separations once appropriate materials and modules are developed. Hybrid processes such as utilizing membrane modules to azeotropes formed during distillation are particularly attractive because they can offer less process complexity and reduced capital investment. A pervaporation
performance was studied using pervaporation through the polymer blendmembranes for the separation of benzene and cyclohexane mixtures to investigate the relationship between pervaporation performance and polymer blend design. Solubility parameter calculation and thermodynamic calculation were used to predict the pervaporation performance for the benzene and cyclohexane mixture system using polymeric blend membrane composed of NBR, PVC and polar copolymers with various solubility parameters. The solubility parameter of the polymer blend
membranes were controlled with different blend ratio. Screening of the membranes was accomplished by simple swelling experiments. Selectivity for the polar component increased with increasing NBR and PVC contents. Solubility parameter from polar and hydrogen bonding properties and activity calculated from thermodynamic model predicted the trend of swelling characteristics and
pervaporation performance. Solubility parameter and thermodynamic calculation provide an a priori methodology for seeking the best blend formulations.
Effect of Boron on Solidification Microstructure in a Single Crystal Superalloy
Authors: Jo Chang Yong , Kim D.H. , Yoo Yeong Seok , Ye D.H. , Lee Jung Hun
Published: March 2009

Carbon and boron were mainly considered to strengthen grain boundaries formed during single crystal casting of complex shaped components. However, those elements cause segregation forming the phase with low melting temperature or with brittle nature. To determine the optimum amount of these elements, the effect of boron on solidification behavior was investigated in the C doped single crystal RR 2072 alloy. The solid/liquid interface morphologies and the solidification microstructures were studied at various solidification rates and with B addition by directional solidification.
Sound Absorption Properties of Al Foam
Authors: Kim Sang Youl , Park Soo Han , Um Yong Su , Hur Bo Young
Published: March 2009

Aluminum foam with 0.2 g/cm3 density showed a good sound absorption property at
frequencies higher than 2000 Hz. Compressed aluminum foam with an air gap of 50 mm or higher exhibited a very high sound absorption property near 400 Hz.
Photocatalytic Activities of Plasma Sprayed TiO2-Based Coatings
Authors: Chen Huang , Lee Soo Wohn , Kim Ho Seob , Lee Eun Ah , Kim Tae Ho , Shin Jae Heyg , Aum Ho Sung , Hur Bo Young
Published: March 2009

Plasma spraying technique was used to deposit thin TiO2-based photocatalytic coatings on a foamed aluminum. Before spraying, the composites of nano-TiO2 powder (P25) and nano- ZnO/CeO2/SnO2 powders were agglomerated into microsized powders by a spray-drying process. XRD, SEM, TEM, XPS and the photocatalytic activity evaluation by the decomposition of benzene were applied to characterize the starting powders and the coatings, respectively. The results showed that all the three plasma sprayed TiO2-based coatings were the mixture phases of anatase and rutile. The XPS spectra results revealed that the oxygen element was composed of three kinds of chemical states, i.e., crystal lattice oxygen, hydroxyl oxygen and physical-adsorbed oxygen. The plasma sprayed 90%TiO2-10%CeO2 coating and 90%TiO2-10%SnO2 coating exhibited similar
photocatalytic activity, which was higher than that of 90%TiO2-10%ZnO coating.
Fabrication of Silicon Nitride Ceramics with Electrical Conductivity
Authors: Kim Yoon Ho , Sekino Tohru , Kawaoka Hirokazu , Kusunose Takafumi , Nakayama Tadachika , Niihara Koichi
Published: March 2009

The electrical conductivity was provided to structural ceramics by controlling the
grain boundary phase. We focused on the grain boundary phase of Si3N4 ceramics, which can be considered as an infinite network for conducting paths. In this study, we investigated the correlationship of the microstructure, mechanical properties, and electrical conductivity of Si3N4 ceramics with V2O5 based glasses. The Si3N4 ceramic with V2O5 based glasses were successfully fabricated by controlling the composition of grain boundary phase. Fabricated materials by a PECS method indicated a very fine microstructure. The mechanical properties
of Si3N4 ceramics with V2O5 based glasses were not good compared to those of conventional Si3N4. However, the values for the SNVB and the SNVBA were four or six orders of magnitude higher at room temperature and had excellent mechanical properties compared to pure V2O5 based glasses.
Characterization of Iron and Its Nitride Nanoparticles Prepared by CVC Process without Using a Chiller
Authors: Lee D.W. , Jang Tae Suk , Lee Dae Hoon , Kim Byoung Kee
Published: March 2009

Iron and its nitride (e-Fe3N) nanoparticles were fabricated by the CVC using Fe(CO)5 precursor without the aid of LN2 chiller. The iron particles synthesized at 400 oC were a mixture of amorphous and crystalline a-Fe. Fully crystallized iron particles were then obtained above 600 oC. Iron-nitride particles that were easily formed at 500 oC at 1 atm., however, were not fully developed in vacuum unless the reaction temperature reached 850 oC. Nevertheless, the work chamber needed to be maintained in vacuum to obtain finer iron-nitride particles. The synthesized particles possessing the core-shell type structure were all nearly spherical and enclosed with Fe3O4 or Fe3O4-related amorphous layer. The iron nanoparticles (~20 nm) synthesized at 600 oC at 760 torr exhibited iHc ~ 1.0 kOe and Ms ~ 170 emu/g, whereas the iron-nitride particles (~20 nm) synthesized at 850 oC at 0.01 torr exhibited iHc ~ 0.45 kOe and Ms ~ 115 emu/g.
The Preparation of Rutile TiO2 Doped with Rare Earth Metal Ions, Sulfur and Their Photocatalytic Properties
Authors: Gao Lian , Liu Hong Yan , Sun Jing
Published: March 2009

Small quantities of lanthanum, yttrium and sulfur are doped in rutile n-TiO2 that was
synthesized by an in-situ hydrothermal method. Their photocatalytic activities are characterized by the degradation of methylene blue (MB) under UV-Vis and visible light irradiation. The results show that lanthanum and yttrium ions are rich on the particle surface, which not only makes the surface energy decrease but also inhibits the recombination of photoexcited carriers, while S-doping produces
states in the band gap of TiO2 that absorb visible light. Compared to the S-doping, La-doping, and Y-doping, respectively, the synergistic effects of (S, La)-codoping and (S, Y)-codoping result in a higher photocatalytic activity under visible light irradiation.
Effect of Oxide Additives on the Aspect Ratio Control of Mullite Whiskers
Authors: Park Sang Yeup , Kim Sung Whan , Bang Hee Gon
Published: March 2009

Mullite whiskers were synthesized by the reaction of fly-ash and alumina powder. During the reaction process, the effect of oxide additives on the formation of mullite whisker was investigated. Mullite whisker was synthesized above 1350oC with the addition of excess alumina, and the aspect ratio of mullite whisker increased with increasing sintering temperature and time. Also, the aspect ratio of mullite whisker is dependent on the liquid phase based on silicate composition. The effect of various
oxide additives on the aspect ratio of mullite whisker was investigated.
Electrochemical Characteristics of Si/Mo Multilayer Anode for Microbattery in MEMS
Authors: Jung Ju-Young , Kim Myung Hoon , Moon Hee Soo , Park Jong Wan
Published: March 2009

We have prepared the Si/Mo multilayer consisting of active/inactive material using rf/dc magnetron sputtering. The pre-treatment using an ECR plasma were introduced at current collector for the adhesion and removal of surface contamination. The structural and electrochemical characteristics of multilayers have been investigated. The multilayer nearly maintained more than 90 % of the initial capacity (2653 mAh/g) after 100 cycles whereas the Si thin film was gradually degraded after 40 cycles.
Charge/Discharge Characteristics of SnO2 Electrodes for Lithium Polymer Batteries
Authors: Kim Jong Uk , Kim Jin Kyu , Choi Jae Won , Kim Yeon Hwa , Ahn Jou Hyeon , Kim Guk-Tae , Jun Dae Kyoo , Gu Hal Bon
Published: March 2009

The purpose of this research is to develop tin oxide electrode for lithium ion polymer
battery. We have investigated cyclic voltammetry and charge/discharge cycling of SnO2/SPE/Li cells. The first discharge capacity of SnO2 anode was 612mAh/g. The discharge capacity of SnO2 anode was 560 and 376mAh/g at 2nd and 15th cycle at room temperature, respectively. The SnO2 composite anode with PVDF-PC-EC-LiClO4 electrolyte showed good cycling performance.
Synthesis and Electrochemical Study of Zr-Doped LiNixMnyCo(1-x–y)O2 as Cathode Material for Secondary Li-Ion Battery
Authors: Na Seong-Hwan , Kim Hyun Soo , Moon Seong In
Published: March 2009

In this work, a simple way was contrived to enhance the rate capability and cycle life of LiNixMnyCo(1-x-y)O2 by doping Zr into the material. Zr-doped LiNixMnyCo(1-x-y)O2 was synthesized by solution-based synthetic route, and its electrochemical performance was investigated as 2016 coin-type half cell. With doping, some impurity peaks appeared in the XRD pattern, which seems to
be related to Zr containing oxides. The enhanced characteristics in the rate capability and cycle life might be the result of the protective effect of Zr oxide against the decomposition of electrolyte and a faster Li diffusion rate.
Transformation Behavior and Mechanical Properties of an Equiatomic Ti-Ni Alloy with Surface Sulfide Layers
Authors: Nam Tae Hyun , Park Soo Moon , Cho Gyu Bong
Published: March 2009

Surface sulfide layers were formed on the surface of Ti-50.0(at%)Ni alloys by isothermal annealing at 873 K for 3.6 ks under the sulfur pressure of 80 kPa, and then transformation behavior and mechanical properties were investigated by means of differential scanning calorimetery(DSC), thermal cycling tests under constant load, and tensile tests. The DSC peaks were broadened and
martensitic transformation start temperature(Ms) increased from 281 K to 289 K by sulfurization. An equiatomic Ti-Ni alloy with surface sulfide layers showed good shape memory characteristics and partial superelasticity.
Thermal Sulfidation Behavior of Ti-Ni Alloys
Authors: Nam Tae Hyun , Park Soo Moon , Cho Kwon Koo
Published: March 2009

Ti and Ni sulfides were formed on the surface of Ti-Ni alloys by isothermal annealing at various sulfur pressures, and then microstructures of the surface sulfide layers were investigated by means of scanning electron microscopy and X-ray diffractions. Morphology of sulfurized surface changed from granular shape to porous shape at the sulfur pressure of 80 kPa, which is related to the change in sulfide from NiS1.97 to NiS. Two-layered sulfide was observed in which the inner layer was mainly Ti8.2S11 , and the outer layer was a mixture of NiS1.97 and NiS. The discharge curve of the Ti and Ni sulfides cathode formed on the Ti-Ni current collector at the first cycle showed a plateau voltage of 1.6 V, and the discharge capacity was found to be about 530 mAh/g-NiS1.97.
Ionic Conductivity of Sodium Ion with NaCF3SO3 Salts in Electrolyte for Sodium Batteries
Authors: Kim Tae-Bum , Park Cheol Wan , Ryu Ho Suk , Ahn Hyo Jun
Published: March 2009

To find out the proper sodium ion conducting electrolyte at room temperature, we
investigated the ac impedance measurement of PVdF gel polymer electrolyte and liquid tetraglyme(TEGDME) with various concentrations of sodium trifluoromethane sulfonate(NaCF3SO3). The concentration of NaCF3SO3 did not severely affect the ionic conductivity. The sodium ionic conductivity using TEGDME with NaCF3SO3 was about 3.3×10-4 S㎝-1 which was lower than that of the PVdF gel polymer electrolyte, 5.0×10-4 S㎝-1. From the viewpoint of ionic conductivity, PVdF gel polymer electrolyte was proper electrolyte for sodium battery.
Preparation of Nano-Sized TiO2 Photocatalysts by a Multi-Gelation Method and Their Application to the Degradation of 2-Propanol Diluted in Water
Authors: Neppolian B. , Yamashita Hiromi , Okada Yusuke , Nishijima H. , Anpo Masakazu
Published: March 2009

TiO2 photocatalysts prepared by a novel multi-gelation method showed good
photocatalytic activity for the degradation of 2-propanol diluted in water by the control of parameters such as particle size, surface area, crystallinity, pore-volume, pore-diameter as well as anatase and rutile phase composition by changing the number of pH swings during preparation. In particular, with this method the phase transition from anatase to rutile at higher pH swing times can be controlled and high purity and uniformity of the TiO2 particles which leads to higher photocatalytic activity of the particles can be achieved. From our experimental results, it has been
observed that TiO2 catalysts prepared by this unique multi-gelation method, i.e., adopting variations in the pH swing, significantly shows higher photocatalytic activity for the degradation of 2- propanol diluted in water. It can be considered a viable alternative over existing commercial methods for the preparation of photofunctional catalysts.
High Temperature Oxidation Behavior of Ti3SiC2 in Air
Authors: Ko J.H. , Hwang Sung Sic , Park Sang Whan , Lee Dong Bok
Published: March 2009

Fine-grained and coarse-grained Ti3SiC2 materials were synthesized by hot pressing using TiC0.67 and Si powders as starting materials. The oxidation between 900 and 1100oC in air resulted in the formation of an outer TiO2 (rutile) layer and an inner mixed layer of TiO2 and amorphous SiO2, accompanying the liberation of carbon into the air. Fine-grained Ti3SiC2 displayed better oxidation resistance than coarse-grained one, with activation energies of 376.5~380 kJ/mol for oxidation.
The Effect of Mould Constraints on the 0.2% Proof Stress of As-Cast Mg-Al Alloys
Authors: Wessen Magnus , Cao Hai Ping
Published: March 2009

When a casting solidifies and cools down in a metallic mould, stresses and strains
develop as a result of uneven temperature distributions, metal shrinkage and mould constraints. At ejection from the mould, the casting usually springs back slightly when the elastic part of the strain is released. However, due to the low flow stress at high temperatures it is likely that the casting also has experienced some plastic deformations, meaning that the dislocation density has increased. This paper discusses how the existence of remaining plastic deformations affects the initial flow
behavior and the yield strength during tensile testing of as cast Mg-Al alloys with different degrees of mould constraints.
The Freedom CAR and Hydrogen Fuels Initiative and Magnesium
Authors: Carpenter Joseph A.
Published: March 2009

The USA’s transportation system is nearly completely dependent on petroleum.
Petroleum is used to satisfy 95 percent of America’s transportation energy needs, consuming two-thirds of all the petroleum used. Since roughly 55 percent of petroleum is imported from abroad, the implications of this dependency on USA’s energy security are readily apparent. Therefore, the U.S. Department of Energy (DOE) and the U.S. Council for Automotive Research (USCAR) announced in January 2002 a new cooperative research effort known as the FreedomCAR Partnership to fund high-risk, high-payoff research into advanced automotive technologies with the potential for dramatically lowering this dependence. The new partnership replaced and built upon the Partnership for a New Generation of Vehicles (PNGV) that ran from 1993 to 2001 [1]. In January 2003, the energy-supply industry joined the FreedomCAR Partnership forming the FreedomCAR and Hydrogen Fuel Initiative (FC&HFI) to develop the technologies needed for the mass production of fuel-cell vehicles using hydrogen as fuel and the infrastructure needed to deliver the hydrogen to the consumer. The goal is to enable the automotive and energy-supply industries to make commercialization decisions in 2015 on largescale introduction of such vehicles and on developing the infrastructure beginning in 2020. The long-term transition of vehicles from gasoline to hydrogen is viewed as critical in lowering the dependence of the U.S. economy on foreign oil, and in reducing the environmental impact of the personal transportation sector. In addition to the longer-term work on fuel cells and hydrogen infrastructure, the FC&HFI conducts research on technologies with the potential for shorter-term energy efficiency and environmental benefits, such as new engine concepts,
lightweight materials, and hybrid propulsion components. Magnesium is one of several lightweight materials being researched. This paper discusses the FC&HFI and its work on magnesium.