bluuebunny/crossref_metadata_2025 huggingface dataset:
Strength and Reliability Performance of Hydroxyapatite Coatings on Titania Treated Ti6Al4V Alloy Using Sol-Gel Precursor
Authors: Balakrishnan A. , Lee Byoung Cheon , Kim Taik Nam , Panigrahi B.B.
Published: March 2009

In this study hydroxyapatite (HA) was coated by sol-gel method on Ti6Al4V alloy
substrates: on micropolished surface and after titania (titanium oxide) treatment. Former shows the
cracks and poor bonding of HA whereas latter shows coating without cracks and higher bonding
strength. The higher bonding strength of HA coating in titania treated sample could be attributed to
the increased roughness by titanium oxide layer.
Preparation of Titanium Oxide Nanotube by Hydrothermal Process
Authors: Qamar M. , Yoon Cho Rong , Oh Hyo Jin , Czoska Anna , Park K. , Lee Nam Hee , Lee K.S. , Kim Sun Jae
Published: March 2009

The TiO2 sol was prepared hydrothermally in an autoclave from aqueous TiOCl2
solutions as starting precursor. Hollow fibers were obtained when sol-gel derived TiO2 sol was
treated chemically with NaOH solution and subsequently heated in autoclave under various
conditions. A systematic analysis of the influence of different NaOH concentrations on the
formation of nanotubes has been carried out using XRD and SEM. The phase structure of the
synthesized material was determined by transmission electron microscopy and found that these
materials are, infact, hollow fibers widely known as nanotubes. From the TEM images, the outer
and inner diameters of the tubes were measured ca. 8 and about 4 nm, respectively, with several
hundred nanometers in length.
Hydrothermal Synthesis of Noble Metal Loaded Tin Oxide Sol Solution for Gas Sensor Application
Authors: Matsushiro Dai , Hashishin Takeshi , Tamaki Jun
Published: March 2009

Noble metal (Au, Pd, Pt) loaded SnO2 sol solutions have been synthesized under
hydrothermal condition. The mixed solution of noble metal chloride (HAuCl4, H2PtCl6, or PdCl2)
and SnCl4 was neutralized with NH4HCO3 solution. The precipitate gel obtained was thoroughly
washed and finally treated under hydrothermal condition (200 oC for 3 h at pH10.5) to obtain
transparent sol solution. From SEM and TEM images of powder or thin film derived from sol, any
noble metal particles could not be observed. However, the grain growth was suppressed when
calcined at 900 oC for noble metal loaded SnO2. The peaks of Sn3d and O1s levels in XPS were
shifted to the lower binding energy side. The electrical resistances of thin films prepared from noble
metal loaded SnO2 sol were larger than that of pure SnO2 thin film. These results suggested that the
noble metals were certainly loaded on SnO2 surface or included in the film to modify the surface state
of SnO2.
Control of Microstructures and Textures in Nanocrystalline Fe-50wt%Ni Foil
Authors: Kim Jong Kweon , Choi Shi Hoon , Park Yong Bum
Published: March 2009

The texture development and the mechanical properties were investigated in a
nanocrystalline Fe-50wt%Ni alloy fabricated by using an electrodeposition method. The as-deposited
texture was characterized by a mixture of major <100>//ND and minor <111>//ND fibre components.
Grain growth occurred in the specimen during annealing above 410oC, and resulted in the texture
change that the <111>//ND fibre component developed strongly with decreasing <100>//ND fibre
component. This texture evolution was attributed to the abnormally rapid growth of the <111>//ND
grains, which became much coarser than the <100>//ND and other oriented grains in the fully
annealed specimen.
Preparation of Nickel Nanoparticles in Water-in-Oil Microemulsion
Authors: Lee Young Il , Shim In Keun , Lee Kwi Jong , Joung Jae Woo
Published: March 2009

Nickel nanoparticles were prepared by reduction of nickel-hydrazine complex with sodium
borohydride (NaBH4) in water-in-oil (w/o) microemulsion of PVP/ethanol/toluene/water at 50C. It
was investigated through SEM and TEM photographs that the nickel nanoparticles with a diameter
15~20nm were nearly monodispersed. By the analysis of XRD, the resulting particles were
characterized to be pure crystalline nickel with a face-centered cubic structure. The results indicate
that the size, shape and distribution of particles depend on the mole ratio of [water]/[PVP] and
[NaBH4]/[Ni]. Also, it was found that particle size could be controlled by the kinds of surfactants.
Chemical Durability and Anti-Microbial Property of Silver-Doped Colloidal Silica
Authors: Mun Byung Bae , Kim Ho Kun , Park Jin Koo
Published: March 2009

Silver-doped silica gel was prepared by the reaction of colloidal silica and AgNO3. In the
synthetic process, aluminum ions promote the chemical durability of silver-doped silica gel with
dramatically decreasing the elusion of silica ions at the aqueous solution. Especially, aluminum ions
induce slow release silver ion of silver-doped silica gel over a long period of time. Also, antimicrobial
effects evaluated using a shake flask method resulted in a disinfection ratio of
Staphylococcus aureus(ATCC 6538) and Escherichia coli(ATCC 25922) of over 99.9%, indicating
high anti-microbial properties.
Nano Structured Silica Aerogel Films by Dip-Coating Process
Authors: Heo Deog Do , Oh Young Jei , Jun B.S.
Published: March 2009

The optimum values of the porosity, pore size and transmittance of the coating layer were
investigated to give the lower thermal conductivity of the smart glazing. The porosity of the aerogel
film is 90%, and the pores with 50micron size are uniformly distributed through the film. The
transmittance and thermal conductivity of smart glazing with 500 μm thickness is at about 80 % in
the visible range(380-780nm) and 0.15 W/(m.K) respectively.
TEM Analysis of Multilayered Co/Cu Nanowire Synthesized by DC Electrodeposition
Authors: Choi Soon Mee , Cho Jiung , Kim Young Keun , Kim Cheol Jin
Published: March 2009

As-received multilayered Co/Cu nanowire arrays were examined by TEM, which were
synthesized by pulsed DC electrodeposition using anodized aluminum oxide (AAO) templates. The
multilayered Co/Cu nanowire exhibited magnetism in the perpendicular direction to the long wire
axis. These nanowire can be applied to sensor array, magnetic bead(biocompatible), MRI contrast
enhancing agent, ferro-fluid. Although the characterization of the multilayered Co/Cu nanowire
using XRD and VSM and microstructural analysis using TEM on the bare nanowires extracted from
AAO templates have been reported, interface analysis between Co and Cu phase or HREM analysis
has not been reported in detail. We have prepared TEM specimen with large thin area which was
appropriate for the interface analysis between Co and Cu layer without removing AAO templates
using tripod polishing method. Tripod polishing proved very efficient to secure the large observable
area during TEM session since the polishing angle can be precisely controlled, regardless of the
mechanical strength differences in constituents. Thus we could observe not only the interface
between Co and Cu layer but also the interface between the metallic layers and AAO
templates. Microstructure, composition, and the concentration variation of each Co and Cu layer and
the interfaces were analyzed with TEM and STEM.
Adsorption Characteristics of Uranyl Ions on Carboxymethylated Polyethyleneimine (CM-PEI) / Activated Carbon Composites
Authors: Choi Ke Chon , Jung Yongju , Kim Seok , Park Soo Jin , Lee Hyung Ik , Kim Ji Man
Published: March 2009

We present the adsorption characteristics of uranyl ions on a new and innovative composite
which was composed of a carboxymethylated polyethyleneimine (CM-PEI) and an activated carbon
(F400) with a nanopore less than 2 nm in diameter. In this study, we examined the adsorption
phenomena of uranyl ions on the CM-PEI/F400 composite and evaluated the adsorption data using
various isotherm models. It was found that the adsorption of uranyl ions on the CM-PEI/F400
composite obeys the Langmuir isotherm model. In addition, it was observed that pH of solutions had
great influence on the adsorption capacity of uranyl ions on the CM-PEI/F400 composite. Specially,
the adsorption capacity of uranyl ions was linearly increased with an increase of pH at pH > 3.0.
Interrelation between Strain Relaxation and InxAl1-xAs Compositional Graded Step Buffer Layers on GaAs Substrate Grown by Molecular Beam Epitaxy
Authors: Hwang Sook Hyun , Park Yu Mi , Jeon Hoon Ha , Noh Kyung Seok , Kim Jae Kyu , Moon Joon He , Song Han Jung , Leem Jae Young , Jeon Min Hyon
Published: March 2009

We have grown delta-doped In0.5Ga0.5As /In0.5Al0.5As heterostructures on GaAs substrate
applying with InxAl1-xAs compositional graded-step buffers, called metamorphic structures, grown
by molecular beam epitaxy. Three types of buffer layers with different compositional gradients and
thicknesses have designed to investigate the influence of the strain relaxation process. We
characterized the samples by using transmission electron microscopy, triple-axis X-ray diffraction
and Hall measurement. Two samples with different compositional gradient show almost same
results in electrical properties. On the other hand, it is found that samples with different step
thicknesses had shown the large differences in epilayer tilt and mosaic spread in the step-graded
buffers. These results indicate that there exists an interrelation between the strain-relaxed buffer and
2DEG transport properties.
Synthesis and Characterization of Bioactive Sodium Titanate Nanotube by Alkali Hydrothermal Treatment
Authors: Kim Yun Jong , Kim Sang Bae , Cho Keon Joon , Kim Taik Nam , Cho S.B.
Published: March 2009

In the present work, surface treatment of surgical implant Titanium alloy with micro
bioactive nanotube was experimented. Surface treatment of Ti-6Al-4V bio-implant carried out by
giving alkali hydrothermal and heat treatment. The specimens were treated in 1M NaOH at 100, 150,
200°C for different holding time of 2 hr, 4 hr, 6hr, 12 hr, 24hr & 48 hr. The hydrogel layer generated
during the alkali treatment was crystallized to sodium titanate (Na2Ti6O13) and resulted into the
formation of nano sized tubes on heat treatment. X-ray Diffractrometry (XRD), Scanning Electron
Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the different phases and
surface morphology of these nanorods. The biocompatibility test done using Simulate Body Fluid
(SBF) showed that the Hydroxyapatite (HAp) was well formed at the sodium titanate nanotube layer
generated on the Ti-6Al-4V specimen. The best condition for this increase in surface
biocompatibility was optimized to 6 hours hydrothermal treatment under 200°C using 1 M NaOH
followed by 1 hour heat treatment at 600°C.
Activation and Gas Sorption Properties of Nano-Size Titanium Powder Getters
Authors: Park Mi Young , Ha Ho , Kim Won Baek , Park Je Shin , Suh Chang Youl , Woo Saet Byul
Published: March 2009

Non-evaporable getters (NEGs) are characterized by two major properties i.e. the
activation and gas sorption rate for specific gases. Most of the commercial getters are alloys
composed of micron-size powders. There have been speculations on the advantage of using nanosize
powders as getter material for the obvious increase in volume to surface area ratio and for
effective reaction with gases on size reduced particles. In this study, titanium powders of about 80
nm were prepared by electrical wire explosion method and their gettering properties were measured
in accordance to ASTM standard. The activation of nano-size titanium powders was completed at
about 450oC and the sorption rate was over 4 times higher than those of the micron-size titanium
powders.
Electrical Properties of ZrO2 Capacitor Dielectrics Deposited by rf Magnetron Sputtering
Authors: Lee Chong Mu , Yim Keun Bin , Park Anna , Kim Ho Jin
Published: March 2009

The structure and electrical properties of ZrO2 dielectric thin films deposited by rf
magnetron sputtering were investigated. The fixed oxide charge and interface trap density at the
ZrO2/Si interface is substantially decreased by annealing at 500 C. Annealing treatment also enhances
the quality of the film by reducing leakage current. The carrier transport mechanism in the ZrO2 film
is dominated by thermionic emission.
Effect of Cell Size on the Dynamic Compressive Properties of Aluminum Alloy Foams
Authors: Wang Zhi Hua , Ma Hong Wei , Zhao Long Mao , Yang Gui Tong
Published: March 2009

The static and dynamic compressive behaviors of open-cell aluminum alloy foams with
virtually the same relative density of 0.4 were investigated. The foams have different cell sizes
(0.5mm, 1.5mm, 2.5mm) but similar cell morphology and microstructure. The yield strength of these
foams was characterized as a function of strain rate and cell morphology. The experimental results
indicated that the mechanical responses of foams are sensitive to strain rate, and dependent of the cell
size. The present results are compared in details with recent findings obtained from the aluminum
foams.
Mechanical Behaviors of Ultrafine Grained Metallic Materials
Authors: Shin Dong Hyuk , Hwang Duck Young , Ahn Jung Yong , Park Kyung Tae , Kim Yong Suk , Park J.J.
Published: March 2009

Ultrafine grained materials fabricated by severe plastic deformation exhibit both superior
and inferior mechanical properties, as the prominent structural materials, compared to coarse
grained counterparts. The superior mechanical properties are ultrahigh strength and exceptional
ductility at high temperatures (i.e., superplasticity). The inferior mechanical properties are lack of
strain hardenability and room temperature ductility. In this study, the relationship between
microstructure and mechanical properties of ultrafine grained materials fabricated by severe plastic
deformation is investigated in order to provide insight broadening their future applicability.
Hertzian and Nanoindentations on EBPVD-Coated Gadolinium Zirconate Thermal Barrier Materials
Authors: Jung Kyu Ick , Park Sang Hyun , Kim Jong Ho , Kim Do Kyung , Paik Ung Yu , Lee Kee Sung
Published: March 2009

New gadolinium-yttrium zirconate thermal barrier coating(TBC) material is deposited by electron beam PVD method, as an alternative to YSZ TBC layer for gas turbine blade applications. XRD analysis reveals that the new TBC material consists of thermally stable pyrochlore structure. Hertzian and nanoindentation evaluations reveal that gadolinium zirconate materials show superior properties as a TBC candidate material with high mechanical properties. The Y2O3 doping improved hardness and elastic modulus of TBC layers. The indentation stress-strain curves by Hertzian indentation and the load-penetration depth curves by nanoindentation indicate that the new TBC layer has higher damage resistance combined with superior thermal insulation properties rather than commercial YSZ coatings.
Effects of Oxygen on Phase Stability and Mechanical Properties of Quenched Ti-Nb Alloys
Authors: Kim Won Yong , Kim Han Sol , Lim Sung Hwan
Published: March 2009

The effects of oxygen content on microstructures, elastic modulus and tensile properties of
quenched Ti-Nb alloys were investigated in order to design a desirable Ti based alloy through casting
process. From the microstructural and phase analysis, it is evidently revealed that the volume fraction
of β phase increased with increasing content of oxygen, and the occurrence of intermediate ω phase
was suppressed in metastable β Ti-Nb based alloys. Martensite transformation temperature decreased
with increasing content of oxygen. Therefore, it is suggested that oxygen acts to stabilize β phase
rather than α stabilizer in quenched state. Yield strength increased with increasing content of oxygen
without a large consumption of ductility in metastable β Ti-Nb based alloys. The variation of
mechanical property was explained by the phase stability, phase formation and microstructure in
correlation with oxygen and Nb content.
Fatigue Crack Growth of Ultrafine Grained Pure Ti after Severe Plastic Deformation
Authors: Hyun Chang Young , Kim Ho Kyung
Published: March 2009

Fatigue crack growth behavior of the ultrafine-grained pure Ti produced by ECAP was
investigated. The ECAPed sample with a total strain of 4.6 showed nearly equiaxed grains with an
average size of about 0.3 μm. After ECAP, the ultimate tensile strength was increased by 60%, while
the tensile elongation was decreased by 31%. The ECAPed Ti showed much higher resistance in
fatigue crack growth by about a factor of 4 over the whole +K due to plasticity-induced crack closure.
Tribological Characteristics of Coarse and Ultra-Fine Grained Ferrite-Martensite Dual Phase Steel Fabricated by Equal Channel Angular Pressing
Authors: Kim Yong Suk , Yu Hyun Seok , Shin Dong Hyuk
Published: March 2009

The dual phase steel, which consists of hard martensite islands embedded in a ductile
ferrite matrix, is known to possess high strength, toughness, and superior wear resistance. However,
the detailed wear mechanism of the steel has not yet been understood thoroughly. In the present study,
dry sliding friction and wear characteristics of an ultra-fine grained ferrite-martensite dual phase steel
has been investigated at room temperature. Wear tests of the steel were carried out using a pin-on-disk
wear tester against an AISI 52100 bearing steel ball at loads ranging from 1N to 10N. Normalizing
heat treatment was also performed on the steel to produce a ferrite-pearlite microstructure, and the
wear characteristics of the normalized specimen were compared with that of the dual phase steel. The
dual phase steel exhibited lower wear rates than the normalized steel, but the steady-state friction
coefficients of the two steels were similar. The wear of the dual phase steel proceeded with a
tribochemical reaction on the wearing surface accompanied with subsurface strain hardening, which
explained the lower wear rate of the steel.
Iron Nanostructures Fabricated by Electron Beam Induced Deposition and its Magnetic Properties
Authors: Furuya Kazuo , Takeguchi Masaki , Mitsuishi Kazutaka
Published: March 2009

Electron beam induced deposition (EBID) was carried out with gas introduction systems
attached to field emission scanning electron microscope (FE-SEM). Using iron carbonyl and
ferrocene, three dimensional (3-D) antenna structures were fabricated in the range of 30-50 nm in
diameter and 500-1000 nm in size. Post-deposition annealing of iron nanostructures resulted in the
formation of crystalline alpha-iron and iron carbide phases. The iron concentration was controlled by
the partial pressure of iron carbonyl and ferrocene. Electron holography observation with field
emission transmission electron microscopy (FE-TEM) revealed that the remanent magnetic flux
density Br of the nanostructures also depends on the iron concentration.
Microstructure Changed during Accumulative Roll Bonding of Al/Mg Composite
Authors: Chen M.C. , Wu Wei Te
Published: March 2009

In this study, the ARB process is used and the Al(1100)/Mg (AZ31) alloys which is
chosen. Steps of 12 layers are created. The ARB process creates a multilayer compound between
Al/Mg layers with excellent bonding characteristics and fine grained microstructure. The bonding
condition became ascendant gradually with increased from 1 to 3 cycles. The grain sizes of Al and
Mg alloys were reached to 875 nm and 656 nm after 3 cycles. The hardness of the Al and Mg alloys
were raised to 42Hv and 90Hv after 3 cycles.
Titanium Alloys Casting for Structural Application
Authors: Sung Si Young , Choi Bong Jae , Kim Young Jig
Published: March 2009

The aim of this study is to clarify the metal-mold reaction for the economic net-shape
forming of titanium and titanium alloys. The metal-mold reactions between pure titanium, TiAl
alloys and Al2O3 mold were examined in a plasma arc melting furnace. The alpha-case generation
between pure titanium and Al2O3 mold could not be explained by the conventional α-case formation
mechanism, which is known to be formed by the interstitials, especially oxygen dissolved from mold
materials. However, based on the interstitial and substitutional α-case formation mechanism, the
α-case formation between pure titanium and Al2O3 mold, and α-case free casting of TiAl alloys
against Al2O3 mold can be explained. On the basis of the interstitial and substitutional α-case
formation mechanism, α-case controlled net-shape forming of titanium and TiAl alloys can be
possible for the structural materials.
Mechanical Properties of Si3N4 Ceramics Prepared by Nitrided Pressureless Sintered (NPS) Process
Authors: Kang Chang Gyu , Park Joong Gwun , Kang Tae Won , Kim Chul , Kim Tae Woo , Han In Sub , Lee Kee Sung
Published: March 2009

As an alternative to degassing pipe and rotor blade using in molten aluminum industry, we
investigate the mechanical properties of silicon nitride ceramic components prepared by nitrided
pressureless sintered (NPS) process, which process is the continuous process of nitridation reaction
process combined with pressureless sintering. Mechanical properties of silicon nitride prepared by
NPS process with sintering additives of 5wt% Y2O3, 5wt% Al2O3 and 20wt% Si show high strength,
>500 MPa, high hardness, 12.6 GPa, and superior damage tolerances with high fracture toughness,
9.8 MPam1/2.
Thermotransport of Hydrogen in Zr-1.0Nb-1.0Sn-0.1Fe Alloy
Authors: Kang Joung Ah , Lee Kwon Yeong , Kim Gyung Guk , Kim Ji Hui , Kim Sun Doo , Yoon Chong Seung , Lee Kyung Jong , Kim Seon Jin
Published: March 2009

Hydrogen redistribution caused by thermotransport in the Zr-1.0Nb-1.0Sn-0.1Fe alloy under
the temperature gradient which is likely to be encountered between nuclear fuel cladding and primary
cooling water (300-340) was investigated. The heat of transport (Q*) of hydrogen was determined
by using a steady state technique to evaluate the magnitude and direction of thermotransport of
hydrogen in the alloy. The values of Q∗ were 23.1, 23.7 and 27.1 KJ/mol for the hydrogen
concentration of 73.4, 75.8 and 94.3 ppm by weight respectively. In other words, hydrogen was
transported from hot region to cold region and the value of Q∗ increased with increasing overall
hydrogen concentration. The Zr-1.0Nb-1.0Sn-0.1Fe alloy had the smaller Q∗ value than that of
Zircaloy-4 when compared with same overall hydrogen concentration. Thus, Zr-1.0Nb-1.0Sn-0.1Fe
alloy has better resistance to the formation of hydride due to thermotransport than Zircaloy-4 does.
Microstructural Evolution in CuAlNi Alloy with Ageing
Authors: Yang Gon Seung , Lee Jong Kook , Jang Woo Yang
Published: March 2009

This research has been performed to investigate the effect of ageing onto the grain
refinement of 82wt%Cu-13.5wt%Al-4.5wt%Ni-0.1wt% misch metal alloy with ageing temperature
and time. The variation of transformation temperature with ageing has been found to be heavily
dependent on ageing time and temperature. In the second reversed transformation cycle, the
temperature of Ms point decreases with ageing time at 300, but no variation at 100. The
temperature of As point increases with ageing time at both temperatures. After the second reversed
transformation cycle, the transformation temperature does not show any significant changes in
martensitic phase with ageing, the temperature of Ms point being the same afterwards. Parent phase
after ageing appears to show M18R and N2H martensitic phases depending on the ageing time and
temperature. It is also found that α and γ2 phases are formed only at the condition of 300 and 24h.
Texture and Microstructure in Ni-W Alloy Tape Manufactured by the Powder Metallurgy Process
Authors: Kim Sang Suk , Bae Sung Yeal , Ahn In Sup , Kim Cheol Jin , Kim Ki Won , Cho Kwon Koo
Published: March 2009

Ni-3at.%W alloy tapes for YBCO coated conductor were fabricated by powder metallurgy
process including powder compaction, cold isostatic pressing(CIP), cold rolling and annealing for
recrystallization. The Ni-3at.%W tapes annealed in an atmosphere of 96%Ar and 4%H2 mixing gas
were characterized by X-ray pole figures, orientation distribution function(ODF) and optical
microscopy(OM). The Ni-W alloy tapes were heat-treated at 700~1000°C for the development of
cube texture {001}<100>. The texture analysis indicated that as fabricated tapes have a sharp cube
texture after annealing at 900 and 1000°C. Also, thoroughly recrystallization takes place for the
annealed tapes at the both temperatures and the average grain size of the two tapes is about the same,
which is about 35㎛.
Microstructure and Mechanical Properties of Mg-Zn-Y Alloys Fabricated by Rapid Solidification and Spark Plasma Sintering Processes
Authors: Son Hyeon Taek , Hong J.M. , Oh Ik Hyun , Lee Jae Seol , Kim T.S. , Maruyama Kouichi
Published: March 2009

Mg97Zn1Y2 alloy powders were prepared from gas atomization process, followed by consolidation using spark plasma sintering (SPS) process. The atomized Mg97Zn1Y2 alloy particles were entirely spherical in shape and dendrite microstructure. The compacts sintered by SPS process have values more than 99% of theoretical density. The compressive yield strength was decreased as sintering temperature increased. It is found that the compressive strength showed the maximum value of 303MPa at the sintered specimen under load of 250MPa at 350°C.
Microstructure and Compression Properties of Al-8Fe-2Mo-2V-1Zr Alloys Produced by Extrusion of Melt-Spun Powders
Authors: Jung Taek Kyun , Sung T.J. , Kim Mok Soon , Kim W.Y.
Published: March 2009

Bulk Al-8Fe-2Mo-2V-1Zr (wt.%) alloys were produced by melt spinning which can give
rise to develope a nano crystalline structure in terms of rapid cooling and subsequent hot extrusion.
The bulk alloys exhibited multi-phase microstructures consisting of ultra fine equiaxed grains with
the average grain size of 100nm and a fine intermetallic Al-Fe, Al-V and Al-Zr based phase having
less than 50nm in particle size. From compression test, it was revealed that the bulk alloys have
very high yield strength at both room temperature (942MPa) and elevated temperatures (651MPa at
473K, 500MPa at 573K, respectively).
A Study on Corrosion-Resistant Properties of Unleaded Bi-Containing Automotive Epoxy Primers
Authors: Yang Won Seog , Ahn Seung Ho , Kim Jung Gu , Na Seung Chan , Hwang Woon Suk
Published: March 2009

The aim of this work is to evaluate the difference in the corrosion resistance between
unleaded containing bismuth automotive epoxy primers and leaded one. It was also discussed the
effect of zinc phosphate pretreatment. The specimen coated unleaded epoxy primer showed 0.5V
higher corrosion potential than that of bare steel. The result of salt spray test did not indicate
remarkable difference of corrosion resistance in all specimens above 10 thickness up to 1200
hours. In the cyclic corrosion test, unleaded epoxy primers on phosphated substrate performed
good corrosion properties until 800 hours. The lead free primer performed the equivalent
corrosion resistance as leaded coating on phosphated steel, but slightly inferior to that of leaded
on bare steel. These results show that the pre-treatment of zinc phosphating is effective as well as
pigment changing in performing anti-corrosion properties in automotive bodies.
Study on Nickel Ferrite Formation by Using a Simple Method to Simulate Heat Transfer Surface
Authors: Yeon Jei Won , Choi Kwang Soon , Jung Yongju , Rengaraj Selvaraj , Ha Yeong Keong , Kim Won Ho
Published: March 2009

The condition of a heat transfer surface with boiling is composed of three environmental
components; high temperature, high pressure and water vapor. In general an autoclave or a high
temperature loop system is used for maintaining the required condition. The thermodynamic
relationship of chemical reactions states that the free energy difference (ΔG) is clearly dependent on
the reaction temperature and independent of the reaction pressure if the reaction has no volume
change: (∂ΔG/∂P)T = ΔV ~ 0. Based on the above relationship, the high-pressure term was removed
from the environmental components of the heat transfer surface. A vacuum quartz capsule with a
moisturized metal oxide powder was used to study the formation of nickel ferrite. The feasibility of
this simplified method to simulate a heat transfer surface was confirmed by an analysis of the FT-IR
spectra and XRD pattern during the transformation of a nickel and iron mixed oxide into nickel
ferrite.
Nickel Tungsten Alloy Electroplating for the High Wear Resistant Materials Applications
Authors: Ko Yong Kwon , Chang Gun Ho , Lee Jae Ho
Published: March 2009

Nickel tungsten (Ni-W) alloy coating was electroplated to increase its mechanical
properties. Tungsten cannot be electroplated by itself, however, it is codeposited with other iron
group metals especially with nickel. The morphologies of nickel tungsten coating were varied with
current density. To eliminate the formation of cracks, pulse plating was employed. Crackless nickel
tungsten alloy were obtained in pulse reverse electroplating. Hardness of nickel tungsten coating has
twice higher compared to the normal electroplated nickel.
In2O3 Thin Films Prepared on TiAlN Substrates Using a Triethylindium and Oxygen Mixture
Authors: Kim Hyoun Woo , Hwang Sun Keun , Cho Won Seung , Ko Tae Gyung , Choi Seung Yong , Lee Wan In , Park Sang Eon , Joo Jung Hoon , Kim Dong Ik , Kim Seong Gyoon , Choe Byung Hak , Min Seok Hong , Choi Jae Ho
Published: March 2009

This paper reports the fabrication of indium oxide (In2O3) films using a triethylindium and
oxygen mixture. The deposition has been carried out on TiAlN substrates (200-350°C). We have
established the correlation between the substrate temperature and the structural properties. The films
deposited at 300-350°C were polycrystalline, whereas those deposited at 200°C was close to
amorphous. XRD analysis and SEM images indicated that the films grown at 350°C had grained
structures with the (222) preferred orientation. The room-temperature photoluminescence spectra of
the In2O3 films exhibited a visible light emission.
Piezoelectric Bimorph Microphone with Low Stress Parylene Diaphragm
Authors: Yi Seung Hwan , Yoon Man Soon , Ur Soon Chul
Published: March 2009

This paper describes a micromachined piezoelectric bimorph microphone, which is
built on a low stress Parylene diaphragm with high quality ZnO films. The ZnO thin film has fine
grain with the average grain size less than 1 and the grain orientation is perpendicular to the
substrate. The highest sensitivity of piezoelectric bimorph microphone fabricated in this study is
about 0.74 mV/Pa, which is twice higher than that of an individual segmented electrode. Based upon
the experimental results, we proposed the equivalent electrical circuit model of piezoelectric
bimorph microphone.
Competing Ion Effect of Stabilization by Cr(III) & Cr(VI) in Ettringite Crystal Structure
Authors: You Kwang Suk , Ahn Ji Whan , Cho Hee Chan , Han Gi Chun , Han Dong Yun , Cho Kye Hong
Published: March 2009

In this study, the degree of the substitution of Cr3+ and Cr6+ into the ettringite structure has
been investigated to extent the immobilization potential of ettringite in the field under specific
conditions. Aqueous suspension containing calcium hydroxide, alumium sulfate, CrCl2(trivalent
chromium) and CrO3(hexavalent chromium) was subjected to ultrasound irradiation under
atmospheric pressure to investigate their effects on synthesis of Cr-ettringite. In the result, the
substitution of Cr3+ into Al site takes place in ettringite structure in solution with Cr3+, and
monosulfate/friedel’ salt phase is also formed by occurrence of extra Al ion in solution. However, in
the case of Cr6+, owing to a higher affinity of sulfate anion to form ettringite than that of Cr6+,most of
Cr6+ did not substituted into the crystal structure of ettringite.
Characterization of Anisotropic and Irregularly-Shaped Materials by High-Sensitive Thermal Conductivity Measurements
Authors: Gustavsson M. , Nagai Hideaki , Okutani Takeshi
Published: March 2009

In modern thermal analysis and design involving thermal transport in solid components it
is necessary to apply different modeling of the thermal heat flow in bulk material and across solid
surface interfaces either in shape of a layer or a solid-solid interface. Similar differences occur when
applying different measurement techniques. Some techniques have been developed specifically for
the purpose of performing measurements of bulk properties by removing the influence from thermal
contact resistance between the measurement probe and the sample material. Thermal conductivity
measurements on metal and ceramic objects of various geometries such as thin bars, thin sheets as
well as coatings or layers are here described when using the Transient Plane Source technique. A
summary overview of the recent developments of this technique, including its ability to be applied in
measurement situations covering a wide range of length and time scales, is also presented. Structural
changes in anisotropy can be recorded with high sensitivity by comparative measurements. The
technique may be applied in situations requiring non-destructive testing, e.g. samples of particular
geometry used for mechanical or tensile testing.
Coarsening of MX Nitrides in Cr-Mo-N-X(X=V,Nb,Ti) Ferritic Steels
Authors: Bae Deuck Seung , Jung Woo Sang , Hong Suk Woo , Song Sang Min , Chung Soon Hyo , Hong Kyung Tae , Lee Kyung Sub
Published: March 2009

Ferritic steels have been candidate structural materials for first wall and blanket structures
of fusion power plant since the late 1970’s, when the fast-reactor irradiation showed them to be more
swelling resistant than austenitic stainless steels. In this investigation, the coarsening of MX nitrides
during aging was studied for Cr-Mo-N-X(X=V, Nb, Ti) ferritic steels. During the aging, (V, Nb,
Ti)nitrides were precipitated out. From TEM observation, particle size distribution was confirmed
and size distribution follows a typical log-normal distribution. The coarsening rate of MX nitrides
was correlated with the Oswald ripening equation.
Encapsulation of Municipal Solid Waste Incineration Bottom Ash to Immobilize Cu and Pb via Carbonation Reaction
Authors: Lee Kyung Hoon , Ahn Ji Whan , Cho Hee Chan , You Kwang Suk , Han Gi Chun , Um Nam Il
Published: March 2009

Bottom ash generated from municipal solid waste incinerators in metropolitan areas
contain calcium and aluminum compounds. As a result of a carbonation reaction, calcite and a
calcium aluminum compound (Na6CaAl6Si6O24, Ca2Al2SiO7) as well as amorphous aluminum oxide
can be found in bottom ash. Due to this, Cu and Pb leaching concentrations decrease via a carbonation
process. Recently, the study of artificial carbonation reaction has been actively investigated, but most
of these studies have been carried out utilizing an aqueous solution method with high water content.
In this study, the carbonation reaction takes place in an aqueous environment, but does not occur on
the surface of the particle. However, to cause the encapsulation of a particle with calcite, calcium
aluminum compound and amorphous aluminum oxide, these must be formed on the surface of
particle. Therefore in this study, a low water content encapsulation method of bottom ash from
municipal solid waste incinerator was investigated with a view to immobilize Cu and Pb via a
carbonation reaction. As seem in the results, the encapsulation effect appeared to be successful, with a
water content of 20%.
Fabrication of Lotus-Type Porous NiAl and Ni3Al Intermetallic Compounds
Authors: Ide Takuya , Tane Masakazu , Nakajima Hideo
Published: March 2009

Lotus-type porous NiAl and Ni3Al intermetallic compounds, possessing cylindrical
pores aligned in the direction parallel to the solidification direction, were fabricated by using a
unidirectional solidification technique in a pressurized hydrogen atmosphere of 2.5MPa. The porosity
of lotus NiAl is 24.2 %, and the porosity of lotus Ni3Al is 3.2%; the porosity of the porous NiAl is
larger than that of Ni3Al. This is because the solubility gap of hydrogen between liquid and solid
phases of NiAl is larger than that of Ni3Al.
Gold Nanowire-Network Structure Prepared from Metallic Gold Nanowires Deposited in Polycarbonate Template Membrane
Authors: Jung Ju Yong , Kim Youn Su , Shim Hee Sang , Kim Won Bae
Published: March 2009

A network structure of gold nanowires was prepared from a template synthesis method,
in which gold metal nanowires were first deposited into a polycarbonate track-etched membrane
with pore diameter of 100 or 220 nm via auto-catalytic deposition (i.e., electroless deposition),
followed by thermal treatment to remove the polycarbonate template membrane.
Heterogeneous Photocatalytic Degradation of Chlorophenols over Ag-TiO2 Nano Particles in an Aqueous Suspension
Authors: Rengaraj Selvaraj , Yeon Jei Won , Li Xiang Zhong , Jung Yongju , Kim Won Ho
Published: March 2009

In the present work, TiO2 and Ag-TiO2 catalysts were prepared by an ultrasonic assisted
sol-gel method. The physico-chemical characteristics studies of the newly synthesized catalysts
were carried out by XRD, TEM, EDX, XPS, UV-Visible absorption spectra and an optical
ellipsometry. In order to find out the optical absorption properties of the catalysts, theoretical
simulations have been carried out by using the Tauc-Lorentz oscillator model. Photodegradation
and mineralisation of the chlorophenols were confirmed by the HPLC and TOC measurements. The
rate of a mineralisation trend was observed in the order of P < 2-CP < 2,4-DCP < 2,6-DCP < 4-CP
< 2,4,6-TCP by using the Ag-TiO2 catalyst. The concentration of the main aromatic intermediate
products was considerably lower for the Ag-TiO2 photocatalysts than for pure TiO2. This
experiment demonstrated that the presence of Ag on TiO2 catalysts could enhance the
photocatalytic oxidation of chlorophenols in an aqueous suspension. It was found that the
degradation of the chlorphenols by these catalysts followed the pseudo- first order kinetic model.
Catalytic Cracking of LLDPE over MCM-48
Authors: Jeon Jong Ki , Park Hyun Ju , Yim Jin Heong , Kim Ji Man , Jung Jin Ho , Park Young Kwon
Published: March 2009

Applicability of Al-MCM-48 as a catalyst for the linear low density polyethylene (LLDPE)
degradation was investigated using a thermogravimetric analyzer as well as a batch reactor. The
degradation products were analyzed by GC/MS, GC-TCD and GC-FID. The activation energy of
LLDPE degradation was lowered by the addition of Al-MCM-48. The oil and gas yields were higher
over Al-MCM-48 than those over Si-MCM-48. Al-MCM-48 generated mainly C7-C10 hydrocarbons,
while Si-MCM-48 exhibited the relatively broader distribution of the oil products (C8-C14).
Al-MCM-48 showed high catalytic stability for the LLDPE degradation.
Characteristics of Al Foam with High Porosity by Melt Foaming Method
Authors: Kim Sang Youl , Seong Hwan Goo , Hur Bo Young
Published: March 2009

Al foams with high porosity were fabricated via melt foaming method. In this process, Ca
and TiH2 are used as thickening and foaming agent. The macrostructure of aluminum foams
exhibited homogeneous distribution of fine pore sizes at shorter holding time. From comparison of
the actual pore sizes with ones calculated with modified Ostwald ripening, the measured pore sizes
were well fitted to the calculated ones. These results suggest that hydrogen diffusion through pore
walls from smaller pores to a larger one is the main process of pore evolution at least in the later
period of holding. The detailed are discussed in the context.
Electrochemical Characteristics of Carbon-Supported Metal Nanoparticles Catalysts Prepared by Electrical Deposition Methods
Authors: Kim Seok , Jung Yongju , Lee Young Seak , Park Soo Jin
Published: March 2009

Graphite nanofibers (GNFs)–supported platinum (Pt) catalysts had been prepared by an
electrochemical deposition by controlling an applied potential to a potential of Pt reduction. Pt
nanoparticles were successfully deposited by using potential sweep methods. The catalyst prepared by
18 sweep times showed the lowest resistance and the highest electroactivity. These electrochemical
properties were dependent on the size, loading level, and morphology of catalysts. The influences of
electrochemical condition on the sizes and loading level of catalysts were also investigated.
Investigation on the Sound Absorption and Transmission for Aluminum Foam and its Composite
Authors: Ko Young H. , Son Hyeon Taek , Cho Jae Ik , Kang Chang Seog , Oh Ik Hyun , Lee Jae Seol , Kim Hyoung Mo , Kim J.C.
Published: March 2009

Although glass wool and polyurethane foam are the most widely used sound-absorber and
insulating materials, there are some critical problems related to the environmental issues. In this
reason, there is a lot of attention on the aluminum foam as a sound absorption material, therefore, in
this research, sound absorption and transmission loss properties were studied. The results showed that
low density aluminum foam performed better in both sound absorption and transmission loss and the
properties were improved as increased air cavity and space.
The Effect of Substrate Temperature on the Formation of ITO Thin Films
Authors: Cho Bum Rae
Published: March 2009

Indium tin oxide (ITO) used in many applications such as electronic and optical devices
were deposited on the soda lime glass substrate by an electron beam evaporation techniques from a
mixture of 90wt% of In2O3 and 10wt% of SnO2. The physical, electrical and optical properties of the
ITO films were determined as a function of substrate temperature. The films deposited at 200
showed optimum properties with a strong diffraction peak having a preferred orientation along the
[111] direction. Experimental results showed that sheet resistance and transmittance of the ITO film
increased with an increase in substrate temperature. Surface roughness increased slightly as a function
of substrate temperature because of grain growth.
Effect of ZnO Buffer Layer on the Structure of TiO2 Thin Film Deposited by Magnetron Sputtering
Authors: Cho Myung Hee , Lee Geun Hyoung
Published: March 2009

TiO2 thin films were deposited on both bare Si and Si substrates with ZnO buffer layer
(ZnO/Si) by radio frequency (rf) magnetron sputtering of TiO2 target at a substrate temperature of
500. A mixed gas of Ar and O2 was used for sputtering and O2 flow ratio was changed from 0 to
30%. X-ray diffraction patterns showed that the TiO2 thin films had only rutile structure. The weak
diffraction peak from the (110) plane of rutile structure was observed for the TiO2 film formed on bare
Si substrate. For the TiO2 film on ZnO/Si, the diffraction peak from the (200) rutile structure was
dominant. The diffraction intensity from the rutile structure of TiO2/ZnO/Si was stronger than that of
TiO2/Si. This implies that ZnO buffer layer promoted the crystallization of rutile structure.
Feasibility of Copper-Base Leadframe Preplated with a Cu-Sn Alloy instead of Ni
Authors: Lee Dae Hoon , Jang Tae Suk , Jung J.H. , Hong S.S. , Park E.S. , Lee J.W. , Hahn B.K.
Published: March 2009

A preplated frame (PPF) consisting of Au/Pd/Cu-Sn/Cu substrate, i.e., preplated with a
Cu-Sn alloy instead of Ni commercially used, was fabricated by electroplating and then the
feasibility of the frame as an alternative PPF was investigated. The wettability of the Cu-Sn alloy
was better than that of Ni, resulting in excellent contact with the substrate and smoother surface on
the upper Au/Pd protective layer. By XPS analyses, it was confirmed that Cu atoms in the Cu-Sn
alloy layer did not diffuse through the thin protective layer to the surface at temperatures used in IC
assembly. The wire pull-strength and solderability of the Cu-Sn alloy PPF were almost equivalent
to those of the Ni PPF. However, the former showed much better corrosion resistance than the latter.
Annealing Behavior after Ion Shower Doping for the Fabrication of LTPS-TFTs
Authors: Jin Beop Jong , Lee Joo Yeol , Ro Jae Sang
Published: March 2009

Ion shower doping with a main ion source of P2Hx using a source gas mixture of PH3/H2
was conducted on excimer-laser-annealed (ELA) poly-Si. The amount of as-implanted damage was
observed to increase with acceleration voltage. The measured values of as-implanted damage using a
UV-transmittance was found to correlate well with the ones calculated using TRIM-code simulation.
After activation annealing the sheet resistance generally decreases as the acceleration voltage
increases. It, however, increases as the acceleration voltage increases under the conditions of severe
doping and low temperature annealing. Results of UV-transmission Spectroscopy and Hall
measurements revealed that uncured damage seems to be responsible for the rise in sheet resistance.
Fabrication of Porous YSZ from ZnO-YSZ Cermet
Authors: Hwang Moon Jin , Han Chong Soo
Published: March 2009

Porous YSZ(8 mol% yttria-stabilized zirconia) was prepared by an acid leaching of
ZnO-YSZ composite. The ZnO-YSZ composites were obtained by two different methods, a 1450 °C
sintering of the mechanical mixture of ZnO and YSZ powders or a decomposition of Zn(NO3)2
deposited on YSZ and a subsequent sintering. The XRD (X-ray diffraction) pattern of the composite
indicated that it was a mixture of ZnO and YSZ even after the sintering. Sharp edge or round edge of
YSZ was observed in SEM (Scanning Electron Microscope) image of the porous-YSZ from the
mixture of ZnO and YSZ, or Zn(NO3)2 deposited on YSZ, respectively. The porous YSZ from the
composite having ZnO component greater than 60 wt% shows low mechanical strength. As the ZnO
content of the composite increased, the porosity and gas permeability of the porous YSZ increased.
From the result, it was suggested that ZnO is a candidate to generate pores in YSZ bulk or membrane.
Electronic Properties Carbon Film Using Chemical Process
Authors: Lee Sang Heon
Published: March 2009

Electro-deposition of carbon film on silicon substrate in methanol solution was carried
out with various current density, solution temperature and electrode spacing between anode and
cathode. The carbon films with smooth surface morphology and high electrical resistance were
formed when the distance between electrode was relatively wider. The electrical resistance of the
carbon films were independent of both current density and solution temperature.
Effect of Substrate Texture on Superconducting Properties of YBCO Thick Films
Authors: Kim Young Ha , Sung Tae Hyun , Han Sang Chul , Han Young Hee , Jeong Nyeon Ho , Shin Jae Won , No Kwang Soo
Published: March 2009

On nontextured substrates, YBCO superconducting thick films were fabricated using a
simple screen-printing method, from Cu-free powders (Y2O3 and BaCO3). However, the films have
poor superconducting properties, such as the critical current density, Jc value due to the random
orientation of the films. In this work, we investigate the influence of substrate texture on
superconducting properties of the film. The films screen-printed on the nontextured and textured Cu
substrates were heat-treated by 2-step procedure in air (980 °C 10 sec + 930 °C 90 sec) followed by
oxygen annealing at 450 °C for 1 hr. We speculate that Cu ions diffusion from the textured Cu
substrates is still faster than Cu ions diffusion from the nontextured Cu substrates that CuO formed
excessively in the film deteriorates superconducting properties of the YBCO film.
Surface Modification of Novel Organic-Inorganic Hybrid Dielectrics Using Self-Assembled Monolayers
Authors: Jeong Sun Ho , Kim Dong Jo , Lee Sul , Park Bong Kyun , Moon Joo Ho
Published: March 2009

Using a thermally-crosslinkable organosiloxane-based organic-inorganic hybrid material,
solution-processable gate dielectric layer for organic thin-film transistors (OTFTs) have been
fabricated. The hybrid dielectric was synthesized by the sol-gel process. The surface of the prepared
dielectric was modified by self-assembled monolayers (SAMs) treatment using wet chemical method.
Prior to surface modification, the chemical inertness of prepared dielectric was investigated by
immersing into various solvents such as toluene, acetone, isopropyl alcohol, and DI-water. The
existence of SAMs on the surface of dielectric was confirmed by measuring current density-electric
field characteristics and it was observed that surface morphology of SAMs-treated hybrid dielectric
was very smooth.