bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication of Porous Al2O3 and TiO2 Thin Film Hybrid Composite Using Atomic Layer Deposition and Properties Study
Authors: Park S.J. , Ahn B.K. , Alegaonkar Prashant Sudhir , Shin H.J. , Yoo Ji Beom
Published: March 2009

Atomic layer deposition (ALD) has been used in advanced applications where thin
layers of materials with precise thickness down to the nanometer scale are needed. Using anodic
oxidation, we prepared the porous alumina. Anodic oxidation was carried out in 5C 0.3M oxalic
acid with anodizing voltages (~ 40 V) and two step anodization method. SEM shows that, these
porous anodic oxides are well aligned and organized into high-density uniform arrays. Afterward,
titanium dioxide thin films were coated by ALD on the porous anodic aluminum oxide. ALD films
were influenced by the deposited interface morphology between Al2O3 and TiO2 and narrow
channel of ~ 10 nm was obtained by controlling ALD cycle.
Sinterbility and Mechanical Properties of Zirconia Nanoparticles Prepared by Hydrothermal Process
Authors: Park Sun Hyo , Ryu In Young , Lee Won Jun , Kim Dae Joon , Han Jung Suk , Lee Myung Hyun
Published: March 2009

A hydrothermal method has been used to produce nanoparticles of 3 mol% yttria-stabilized
tetragonal zirconia (3Y-TZP) with high fracture toughness. The effects of reaction temperature and
pH on crystallite size and sintered density, and the influence of Nb2O5 addition into 3Y-TZP on
toughness have been investigated. The particle size increased with increasing the processing
parameters and the influence of temperature was more significant than pH. The density of nanosized
3Y-TZP increased with increasing pH up to 9 and then decreased abruptly with further increase. The
density increased slightly with the reaction temperature up to 140°C and then changed little with
increasing temperature. The toughness increased in proportional to the Nb2O5 content. After sintering
for 1 h at 1270°C, the highest relative density of 98% was obtained from nanoparticles of about 17
nm, prepared at 200°C and pH 9, and the toughness of 3Y-TZP was increased from 2.5 to 8.3
MPam1/2 by addition of 1.2 mol% Nb2O5.
Carbon Nanotube Gas Sensor Fabricated on Anodic Aluminum Oxide
Authors: Hoa Nguyen Duc , Quy Nguyen Van , Choi Gyu Seok , Cho You Suk , Jeong Se Young , Kim Do Jin
Published: March 2009

A new type of gas sensor was realized by directly depositing carbon nanotube on nano
channels of the anodic alumina oxide (AAO) fabricated on p-type silicon substrate. The carbon
nanotubes were synthesized by thermal chemical vapor deposition at a very high temperature of
1200 oC to improve the crystallinity. The device fabrication process was also developed. The
contact of carbon nanotubes and p-type Si substrate showed a Schottky behavior, and the Schottky
barrier height increased with exposure to gases while the overall conductivity decreased. The
sensors showed fast response and recovery to ammonia gas upon the filling (400 mTorr) and
evacuation.
Characteristics of Al-Doped ZnO Transparent Conductive Oxide Films for Solar Cell Applications
Authors: Kim Doo Soo , Oh Byeong Yun , Jeong Min Chang , Myoung Jae Min
Published: March 2009

Al-doped ZnO (ZnO:Al) films for transparent electrode applications in dye-sensitized solar
cells and thin film solar cells were fabricated and characterized. In order to investigate the effect of
crystallinity of the ZnO:Al films to the morphology and optical properties of the etched surface, the
ZnO:Al films were deposited with varying substrate temperature by rf magnetron sputtering system
and then films’ surface was etched in diluted hydrochloric acid (HCl) solution. Surface morphology
of the amorphous ZnO:Al film deposited at room temperature was controllable to have large surface
area, but it was not appropriate for transparent electrode layers due to high electrical resistivity.
However, the resistivities of the ZnO:Al films deposited at the substrate temperatures of 150 and 300
oC were as low as 1.50×10-3 cm. In addition, the surface morphologies of the films deposited at 150
and 300 oC showed larger surface area for dye-sensitized cells and crater shape for light diffusion
through the films, respectively. The surface morphologies and optical properties of the etched ZnO:Al
films are attributed to the crystallinity of the as-fabricated films.
Effect of Adhesive Thickness and Bonding Length on Behavior of Composite Adhesive Joints Subject to Torsion
Authors: Oh Je Hoon
Published: March 2009

Combined thermal and mechanical analyses were used to investigate the effect of joint
design parameters such as the adhesive thickness and bonding length on stress distributions and
torque capacities of tubular adhesive joints with composite adherends. The finite element analysis
was employed to calculate the residual thermal stresses due to fabrication, and the mechanical stresses
were analyzed using the nonlinear analysis of tubular adhesive joints. The analyses reveal that the
stacking angle, adhesive thickness and bonding length have a significant influence on residual
thermal stresses, and consequently failure modes and joint strengths.
Effect of Multipass Severe Rolling Process in the API X65 Steel
Authors: Sim Ho Sup , Cho Ki Seop , Lee Kon Bae , Yang Hyung Ryul , Kwon Hoon
Published: March 2009

In the API X65 steel, effects of rolling and cooling conditions on microstructure and
mechanical properties were studied. In the case of accelerated cooling after multi-pass rolling in the
high/low unrecrystallized range, the tensile strength was 574-670 MPa and the impact toughness was
74-109 J. In the case of accelerated cooled to 550°C and then interrupted by air cooling, on the other
hand, those values were 524-538 MPa and 100-135 J, respectively. Whereas the former exhibited the
continuous yielding, the latter showed discontinuous yielding. In addition, yield ratio increased from
0.59-0.67 to 0.85-0.87, accompanied with the enhancement of yield strength. Ultrafine ferrite grains
formed by the strain induced dynamic transformation during the severe rolling and second phases
formed during cooling were observed. In accelerated cooling and interrupted cooling conditions, main
second phases formed after cooling were martensite and pearlite, respectively. Separation cracking
mostly observed at interfaces of ferrite matrix and second phases, may be attributed to the intrinsic
interfacial weakness.
Difference in Annealing Characteristics of Nanostructured Copper Alloys Processed by Accumulative Roll Bonding
Authors: Lee Seong Hee , Han S.Z. , Lim Cha Yong
Published: March 2009

The difference in annealing characteristics of oxygen free copper (OFC) and
deoxidized low-phosphorous copper (DLP) processed by ARB was studied. The copper alloys
processed by eight cycles of the ARB were annealed for 10 minutes at various temperatures
ranging from 100 to 400°C. The variation of microstructure and mechanical properties with
annealing was significantly different in both copper alloys. In case of OFC, the ultrafine grained
(UFG) structure formed by the ARB still remained up to 200°C, and above 200°C it was
completely replaced with a coarse grained structure due to an occurrence of the conventional
recrystallization. However, in case of DLP, the recrystallization did not occur even at 350°C.
The strength of the OFC also decreased significantly at annealing temperatures above 200°C,
while the hardness of the DLP did not decrease so largely up to 350°C. These differences in
annealing characteristics in both copper alloys were discussed in terms of purity.
Assessment of Tensile and Fatigue Damage in 316L Stainless Steel by Acoustic Emission Technique
Authors: Byeon Jai Won , Kwun S.I. , Kang Kae Myung
Published: March 2009

Acoustic emission (AE) technique was applied to evaluate both tensile deformation of
316L stainless steel and bending-fatigue damage of socket-welded pipe. AE activity was monitored
during tensile deformation of plate-type specimens subjected to various heat treatments. Variation in
RMS voltage of AE signal was correlated with the amount of strain-induced martensite phase.
Secondly, actual size of socket-welded pipe specimen was bending-fatigued under various stresses.
Crack initiation was determined by observing an abrupt increase in AE count, and confirmed by
radiographic examination before and after the crack initiation cycle. Potentials of AE technique for
monitoring fatigue crack initiation were discussed.
Microstructural Evolution during Annealing of 5052 Al Alloy Deformed at Cryogenic Temperature
Authors: Gang Ui Gu , Lee Yong Shin , Park Kyung Tae , Nam Won Jong
Published: March 2009

The activation energy for recovery and recrystallization was calculated using DSC data.
The annealing below 250°C resulted in the bimodal grain size distribution, while that above 300°C
resulted in the uniform distribution of coarse grains. The formation of a bimodal microstructure
would be responsible for the good combination of uniform elongation and tensile strength.
Additionally, the little variation of hardness for different annealing time at 300°C also indicated that
mechanical properties of deformed and annealed 5052 Al alloy were significantly influenced by the
volume fraction of recrystallized grains rather than the coarsening of recrystallized grains.
Effect of Heat Treatment on the Tensile Properties of Poly-Crystal and DS CM247LC Alloy
Authors: Kim In Soo , Choi Baig Gyu , Seo Seong Moon , Kim Doo Hyun , Jo Chang Yong
Published: March 2009

The effect of heat treatment in superalloy CM247LC on tensile properties at various
temperatures has been investigated. In the case of equiaxed poly-crystal specimen, the aged condition
(HTA condition) has higher strength than the solution treated and aged condition (HTSA condition)
at low temperature. The HTSA condition exhibits higher strength than HTA condition in
directionally solidified specimen in all temperature range. Shearing of γ´ particle is a principal
deformation process at the low temperature, and cutting of fine secondary γ´ particle plays important
role in the early stage of deformation in the HTA poly-crystal specimen. Tangles of short misfit
dislocations form at the γ/γ´ interface during the high temperature deformation due to the partial loss
of coherency at the interface. The rafting of γ´ increases tensile strength of the HTSA specimen at and
above 871°C.
Effect of Minor Elements on the Grain Boundary Strengthening of a Single Crystal Superalloy RR2072
Authors: Kim D.H. , Yoo Y.S. , Jo Chang Yong , Jones C.N.
Published: March 2009

Effect of carbon and boron on the grain boundary strengthening of a second generation
single crystal superalloy RR2072 was investigated. Single crystal and bicrystal specimen with three
kinds of tilt type misorientation angle were grown by Bridgman technique. Creep and stress rupture
tests were conducted at 950oC and 1050oC. Rupture life of single crystal of the alloy modified with
carbon and boron was comparable to that of the RR2072 which is free from boron and carbon. TCP
phase precipitation such as sigma was suppressed in the modified alloy during thermal exposure and
creep deformation. Rupture life of the modified alloy bicrystal was superior to that of the RR2072
bicrystal. M23C6 carbide formation and suppression of γ′ band growth is thought to be the role of
minor elements for the grain boundary strengthening of a nickel base single crystal superalloy
RR2072.
Effects of Surface Coating on Wear Properties of A356-20vol.%SiCp Composites
Authors: Lee Jung Moo , Kang Suk Bong , Han Jian Min
Published: March 2009

Thick alumina coatings were performed on A356-20vol.% SiCp composites by micro-arc
oxidation (MAO) process with different processing time. The dry sliding wear tests were performed
on A356-20vol.% SiCp composites with and without surface coating. The samples were tested by
pin-on-disc wear test equipment with different applied load and sliding velocity. It is revealed that
MAO coating improves resistance to wear of A356-20vol.% SiCp composites in the severe wear
conditions. On the basis of the observations and analysis of the worn surface, worn subsurface, wear
debris and variation of friction coefficient, the role of MAO coating layer is examined.
Effects of Mischmetal Addition on the Microstructural Characteristics of BCuP-2 Brazing Filler Metal
Authors: Lee B.K. , Eum I.S. , Han H.K. , Kang C.Y.
Published: March 2009

In this work, the effect of mischmetal (48wt%Ce–27wt%La–14wt%Nd–6wt%Pr)
additions on the microstructural characteristics of an Cu-7wt%P brazing filler metal (BCuP-2) were
investigated. The volume fraction of primary Cu was considerably increased with increasing
mischmetal addition in the BCuP-2. Also, the eutectic structure was changed from lamella to fibrous
morphology and the pseudo-eutectic phase (Cu3P) was formed around the primary Cu with the
mischmetal addition above 0.03wt%. Compound containing a small amount of mischmetal was
formed in the primary Cu phase and this compound acts as the nucleation sites of primary Cu. The
fraction of primary Cu was increased by about 1-2wt% due to the mischmetal rich phase. The
mischmetal rich phase also formed in the pseudo-eutectic phase and this enhanced the formation of
pseudo-eutectic phase. The addition of mischmetal changes the eutectic phase lamella to fibrous by
suppressing both the solid-liquid interfacial energy and the surface energy of the solid. The
mischmetal additions showed a very strong influence on the nucleation process of primary Cu and the
subsequent formation of Cu3P phase as well as the eutectic structure change.
The Heat Treatment Characteristics of Hydroxyapatite Thin Films Deposited by RF Sputtering
Authors: Jung Chan Hoi , Kim Soon Kook , Jang Chang Woo , Lee Jun Hee , Lee Su Ho , Song Jae Sung , Kim In Sung , Jeong Soon Jong
Published: March 2009

RF sputtering process was applied to produce thin hydroxyapatite(HAp,
Ca10(PO4)6(OH)2) films on Ti-6Al-4V alloy substrates. The effects of different heat treatment
conditions on the bonding strength between HAp thin films and Ti-6Al-4V alloy substrates were
studied. Before deposition, the Ti-6Al-4V alloy substrates were heat treated for 1hr at 850°C under
3.0×10-3torr, and after deposition, the HAp thin films were heat treated for 1hr at 400°C, 600°C and
800°C under the atmosphere, and analyzed optical microscope, FESEM, FTIR, XRD, nano-indentor,
micro-vickers hardness, respectively. Experimental results represented that the HAp thin films on
the heat treated substrates had higher hardness than none-heat treated substrates before the
deposition.
Effect of Post-ECAP Aging on Mechanical Properties of Age-Hardenable Aluminum Alloys
Authors: Kim Jong Kap , Kim Woo Jin
Published: March 2009

Equal-channel angular pressing (ECAP) is an efficient method of improving strength of
metallic alloys through (sub) grain refinement to, typically, the sub-micrometer level by introducing
intensive plastic strain into materials through repetitive pressing. In the present study, the post-ECAP
aging effect on strength of age hardenable aluminum alloys (6061, 2024, 7075 Al) was examined and
it could be concluded that pre-ECAP solid solution treatment combined with post-ECAP
low-temperature aging provided much more significant room-temperature strengthening effect than
conventional ECAP processing routes without involving special heat treatments.
Investigation on the Microstructure of an 11% Cr Martensitic Steel with Titanium
Authors: Yin Feng Shi , Jung Woo Sang , Chung Soon Hyo
Published: March 2009

The microstructure of an 11% Cr martensitic steel was investigated in normalized-andtempered
condition. It was found that the microstructure was tempered martensite consisting of
prior γ grains and laths. M23C6 precipitates were mainly distributed along prior γ grain boundaries
and lath boundaries and small amount of M3B2 particles were aligned almost as a line along rolling
direction. MX nano-particles were distributed in the matrix. Complex inclusions containing
titanium were also found in the microstructure. Tensile cracks were easily to nucleate at the
interface between matrix and M3B2 particles or inclusions.
A Characteristics Study of FeAlCr Intermetallic Compound Manufactured by Osprey Forming Process
Authors: Park Su Jung , Lee Hyun Kyu
Published: March 2009

The FeAlCr intermetallic compound has a high possibility to be used as the material of the
aerospace industry, in the internal combustion engine, in the heat exchanger and as the material of
next-generation heat resistant material due to the low density, the excellence in oxidation resistance
and corrosion and the high melting point. The study fixed the Cr content of 6% in FeAl alloy to
improve the Ductile in the room temperature and added MO and Hf to improve the Grain Refinement
and the mechanical properties. This alloy was manufactured by Osprey Forming Process to improve
the ductile and the workability in room temperature and to try to get the low production cost as well.
The microstructure and the Fracture phenomenon of specimens after homogenizing(1,000 °C ,
168hour) and phase stabilizing heat treatment(500°C, 120hour) was observed by SEM, EDS, XRD,
Hardness and Compression. The microstructure of FeAlCr intermetallic compound was changed
from the coarse equixed structure to the minute equixed one because of the addition of Mo and Hf.
The rates of hardness and yield strength of FeAlCr intermetallic compound were increased after Mo
and Hf had been added in it.
Effect of Silver Additions on the Ageing Behavior and Mechanical Properties of Mg-Al-Si-Sn-Sr Alloy
Authors: Lee S.W. , Kim Byung Ho , Nam K.Y. , Song Dae Hyun , Cho Kyung Mok
Published: March 2009

Mg is one of the most promising structural materials for lightweight applications due to its
low density, good castability and damping capacity. In this study, we investigated the effect of silver
(Ag) addition on alloy ageing behavior and mechanical properties of Mg-Al-Si-Sn-Sr-Ag alloys with
variation of Ag contents (0.1, 0.5, 1.0, 2.0wt%). The ageing kinetics of Ag added alloys was
determined and affected by Ag addition. Although the precipitation of platelets of Mg17Al12 within
α-Mg matrix was not significantly affected by the silver, mechanical properties such as hardness and
tensile properties were improved with increasing Ag contents.
Formation of a Crystalline-Glass Composite in a Cu-Based Bulk Metallic Glass by Using the Cu-Pb Monotectic System
Authors: Yoo Dae Han , Kang Hee Sam , Yoon Woo Young
Published: March 2009

To synthesize a crystalline-glass composite in a Cu-based bulk metallic glass, the
monotectic reaction was used. The (Zr-Sn-Pb)-rich crystalline phase was found to coexist with the
(Cu-Ti-Ni)-rich glassy phase during the process of quenching from the melt in the
(Cu47Ti33Zr11Ni6Sn2Si1)100-x+Pbx=1,2 system. Microstructures consisting of uniformly dispersed
crystalline particles in the amorphous matrix were observed by scanning electron microscope (SEM)
and transmission electron microscope (TEM). Compressive tests demonstrated that the fracture strain
of the sample with a Pb content of 1 at% was three times higher than that of the sample with no Pb.
Properties of Preferred Orientation of TiO2 Thin Film on Plasma Pretreated Substrate
Authors: Jhin Jung Geun , Choi Jae Hong , Baek Jong Hyeob , Byun Dong Jin
Published: March 2009

The degree of preference of thin anatase TiO2 films prepared by CVD for the <112>
orientation was enhanced by pretreating the soda-lime glass substrates with a plasma. The
relationships between the preferred orientation and plasma pretreatments were investigated. It was
founded that the TiO2 films on the plasma pretreated soda-lime glass substrates exhibited a higher
degree of preference for the (112) orientation than those without the pretreatment. To confirm the
effect of the plasma pretreatments on the soda-lime glass substrates, TOF-SIMS, contact angle
measurement and TEM were used to determine the changes in the components, surface energy and
crystallinity of the substrates, respectively. It was found the components added as network modifiers,
such as Na+, Ca2+, and K+ ions, was depleted in the surface region of the substrates after the plasma
pretreatment, and that the surface energy of the substrates was increased. Finally, it was observed that
the substrate surface was changed from an amorphous phase to polycrystalline. To sum up, it was
assumed that the surface of the soda-lime glass substrates with their partially crystalline, namely
poly-crystalline, structures artificially induced the thin anatase TiO2 films to develop with a
<112>-preferred orientation. In conclusion, the plasma pretreatment of the glass substrate caused the
TiO2 thin films to exhibit a higher preference for the <112> orientation, thereby optimizing their
photocatalytic efficiency.
Aqueous Dispersion of ZrB2 Powder - Effect of Surface Corrosion and Dispersant
Authors: Lee Sea Hoon , Sakka Yoshio , Kagawa Yutaka
Published: March 2009

Hydrolysis and dispersing behavior of aqueous ZrB2 slurry were investigated. The
isoelectric point (IEP) of ZrB2 slurry was measured to be pH 6.3. The acid and base slurry
underwent rather rapid change of pH after fabrication for one and three hours, respectively. The
oxygen content of the boride powder increased slowly with static ageing time in acid and neutral
slurries, while the value decreased in base slurry. Application of poly(ethyleneimine) changed IEP
of the boride slurry to pH 10.4. Sedimentation test informed that stability of the slurry was
improved when increasing the molecular weight of poly(ethyleneimine) to 70,000 and in acid slurry
(pH 3).
Growth Model of Circumferential Outer Diameter Stress Corrosion Crack in Retired Steam Generator Tube of Kori 1 Nuclear Power Plant
Authors: Kim Dong Jin , Kim Hong Pyo , Kim Joung Soo , Lim Yun Soo , Hwang Seong Sik
Published: March 2009

Growth model of a circumferential outer diameter stress corrosion crack (ODSCC) in a retired
steam generator tube of the Kori 1 nuclear power plant was proposed based on extensive destructive
examinations of the pulled tubes of Alloy 600 from the Kori 1 plant. A small ODSCC grows in a
lateral direction as well as a forward direction until it meets a neighboring ODSCC which also
grows in a lateral direction as well as a forward direction. And then, the two ODSCCs which meet
on the same circumferential plane are consolidated into a single ODSCC. By repeating such a
consolidation process with time, it seems that the apparent growth rate of an ODSCC in the lateral
direction is much faster than that in the forward direction. Growth model of a circumferential
ODSCC from a retired steam generator tube of the Kori 1 plant reveals that many ODSCCs are
initiated and grow in both directions independently until they meet and finally they are consolidated.
Effect of Source Supply Methods on Low-Temperature Preparation of Lead Zirconate Titanate Thin Films Using SrTiO3 Seed Layers by Metallorganic Chemical Vapor Deposition
Authors: Moon Ji Won , Tazawa Shogo , Wakiya Naoki , Kiguchi Takanori , Ishida Youhei , Mizutani Nobuyasu , Shinozaki Kazuo
Published: March 2009

Pb(Zr, Ti)O3 thin films were successfully prepared on (111)Pt/IrO2/SiO2/(100)Si substrates
using SrTiO3 seeds at 290 oC by RF inductive heating type and 350 oC by resistive heating type
metalorganic chemical vapor deposition method (MOCVD), respectively. The SrTiO3 was chosen as
seed layers and prepared by pulsed laser deposition method. The crystal structures and orientations of
SrTiO3 seeds were changed by deposition temperature. In the case of preparation with RF inductive
heating MOCVD, the remanent polarization (2Pr) and coercive field (2Ec) were 42 μC/cm2 and 256
kV/cm, respectively.
Application of Taguchi Method for Optimization of Vacuum Plasma Sprayed CoNiCrAlY Coatings
Authors: Lee Koo Hyun , Ye K.H. , Kim S.T. , Jeon Chae Hong , Song Yo Seung , Seo Jong Hyun , Kim Bae Yeon , Lee Myung Hyun , Cho Nam Ihn , Lee Deuk Yong
Published: March 2009

Bond coatings, CoNiCrAlY, are prepared on Inconel 738 substrate by vacuum plasma
spray (VPS). Mechanical properties of VPSed CoNiCrAlY coatings are investigated via Taguchi
method and L18(21×37)orthogonal arrays to determine the optimal setting and the relationship of
experimental variables. Seven parameters were considered as follows: (A) arc current; (B) primary
gas flow rate; (C) secondary gas flow rate; (D) stand-off distance; (E) working pressure; (F) carrier
gas flow rate (Ar); and (G) powder feeding rate.The effect of carrier gas flow rate on the porosity is
determined to be the highest among the parameters investigated. Higher microhardness values are
observed for the VPSed coatings as compared to the coatings prepared by conventional high
velocity oxygen fuel probably due to low amount of the porosity.
Removal of Slurry Residues in Tungsten Plug during Chemical Mechanical Planarization
Authors: Yang Chan Ki , Park Jin Goo , Jo Jung Hun , Lim Geun Sik , Kim Tae Hyung , Jo In Soo
Published: March 2009

One of key processes in tungsten (W) CMP is to remove slurry particles inside W plug after CMP.
In general, HF cleaning is well known to remove the slurry residue particles in W plugs. HF
chemistry lifts off the particles by etching the plug during scrubbing and effectively removes
particles. It is sometimes impossible to apply HF chemisty on W plug due to the degradation of
electrical characteristics of a device. In this paper, a post W CMP cleaning process is proposed to
remove residue particles without applying HF chemistry. After W CMP, recessed plugs are created,
therefore they easily trap slurry particles during CMP process. These particles in recessed plug are
not easy to remove by brush scrubbing when NH4OH chemistry is used for the cleaning because the
brush surface can not reach the recessed area of plugs. Buffing with oxide slurry was followed by
W CMP due to its high selectivity to W. The buffing polishes only oxide slightly which creates
higher plug profiles than surrounding oxide. Higher profiles make the brush contact much more
effectively and result in a similar particle removal efficiency even in NH4OH cleaning to that in HF
brush scrubbing.
Fabrication and Characterization of Al-Fe Coating for the Wet-Seal Area of Separator for Molten Carbonate Fuel Cells (MCFC) by the Laminating of Al Foil
Authors: Choi Jae Woong , Hwang Gil Ho , Oh Heung Jae , Kang Sung Goon
Published: March 2009

The separator of the molten carbonate fuel cells (MCFC) has the major corrosion problems,
especially wet-seal area, because this part contacts directly with the corrosive molten carbonate
electrolyte. For the protection of the wet-seal area, aluminization method is developed recently.
Coated aluminum reacts with the molten carbonate and forms the LiAlO2 having high corrosion
resistance, high melting point, no electrical conductivity and no dissolution in molten carbonate. In
this study, 50㎛ thickness aluminum foil was applied to form the Al-Fe coating layer on the
AISI316L by using the laminating method. Laminating of aluminum foil on AISI 316L was
performed at 630°C for 5h in Ar atmosphere using a jig and diffusion heat treatment was carried out at
700°C, 750°C and 800°C for 3h in Ar atmosphere respectively. This method simplified the existing
complicated process and has a great advantage of low-cost mass production compared to other
methods like PVD, CVD and spray coating.
Surface Modification and Heat Treatment of Ti Rod by Electro Discharge
Authors: Lee W.H. , Oh N.H. , Kim Y.H. , Cheon Y.W. , Cho Y.J. , Lee C.M. , Kim K.B. , Lee N.S.
Published: March 2009

Single pulse of 2.0 to 3.5 kJ of input energy from 150 μF capacitor was applied in a N2
atmosphere to the cp Ti rod for its surface modification and heat treatment. Under the conditions of
using 2.0 and 2.5 kJ of input energy, no phase transformation has been occurred. However, the
hardness and tensile strength decreased slightly after a discharge due to a grain growth. Using
greater than 3.0 kJ of input energy, the electro discharge process made a phase transformation and
the hardness especially at the edge of the cross-section of the Ti rod increased significantly. The Ti
rod before the discharge was lightly oxidized and was primarily in the form of TiO2. However, the
surface of the Ti rod has been instantaneously modified by the discharge into the major form of TiN
from TiO2. The electro discharge process can thus modify the Ti rod’s surface in times as short as
200 μsec by manipulating the input energy, capacitance, and discharging ambience.
Corrosion of Silicate Glasses and Glass-Ceramics Containing EAF Dust in Acidic Solution
Authors: Kim Hwan Sik , Kim Yoo Taek , Lee Gi Gang , Kim Jung Hwan , Kang Seung Gu
Published: March 2009

The corrosion behavior of glass and glass-ceramics fabricated with silicate glass frit mixed
with 50~70 wt% EAF dust in the acidic solution was analyzed by both heavy metal leaching test and
microstructural observation. The crystallization temperature, Tc of glassy specimens was around 850
measured by DTA and the heat treatment temperature to crystallize a glassy specimen was selected
as 950 / 1 hr. The spinel crystal peaks were found in XRD analysis for the glass containing dust >
60 wt%. For the glass-ceramics, however, the spinel peaks in a specimen containing dust > 50 wt%
was found with weak willemite peaks. The glass and glass-ceramic specimens showed the first stage
of corroding reaction according to Clark models in acidic solution. The glass-ceramic specimens
showed much lower a heavy metal leaching concentration than that of glass specimens in the
corrosion test in acidic solution of pH=2.95. Especially, the glass-ceramics containing dust 60 wt%
showed a heavy metal leaching concentration of 66 % Pb, 60 % Zn and 98 % Fe lower than that of
glass specimens due to crystal phases formed, thermodynamically more stable than a glass network
structure. From the leaching test that more Zn ion leached out than Fe ion, the spinel crystal phase
[ZnFe2O4] showed better corrosion resistant in the acidic solution than the willemite [Zn2SiO4].
Microstructures and Tribological Properties of Plasma Arc Sprayed Al-Fe-Cr-Ti Quasicrystalline Coatings
Authors: Kim Yeon Wook , Kim Hee Jung , Shin Hyun Myung
Published: March 2009

One of the most important use of thermal spray coatings is for wear resistance. In this work,
the tribological properties of plasma prayed Al83.7Fe7Cr6.3Ti3 quasicrystalline coatings have been
studied. The quasicrystal powders of Al-base alloys were produced by gas atomization unit in vacuum.
The plasma spray process was used to produce quasicrystalline coatings. Then, friction experiments
were carried out on a pin-on-disc-type tribometer. The results indicated that the friction coefficient of
Al83.7Fe7Cr6.3Ti3 quasicrystalline coating is about 50% lower than that of Al70Fe13Cu10Cr7
quasicrystalline coating.
Characteristics of 2.45GHz Microwave Plasma by Langmuir Probe Measurements
Authors: Choi Sun Yong , Minami Wataru , Kim Lae Hyun , Kim Hee Joon
Published: March 2009

The characteristics, such as electron temperature and the electron density, of CF4/Ar
discharge in 2.45GHz microwave has been investigated by using a Langmuir probe with the
microwave power and position. The results showed that the electron temperature and the electron
density decrease with increasing distance from the plasma source. Increasing power enhances the
dissociation and ionization of gas, and increases the electron densities. The electron temperature was
decreased by reducing the mean free path of electrons with increasing microwave power. The electron
temperature is 7.63 ~ 2.49 eV, and the electron density is 0.85×1011 ~ 4.3×1011 cm-3. From obtained
electron energy distribution function, we known that high energy electron decreased with increasing
microwave power and distance from the plasma source. The generated plasma by developed our
system has good quality as results of Debye length λD = 35.8 ~ 67.3 μm, and Ln(ND) = 33.4 ~ 35.2.
An Ab Initio Study of the Energies of Coherent Interfaces Formed between bcc Iron and Carbides or Nitrides of Transition Metals
Authors: Jung Woo Sang , Chung Soon Hyo , Ha Heon Phil , Byun Ji Young
Published: March 2009

An ab initio study was carried out on interface energies at coherent interfaces between bcc
Fe and MXs (NaCl structure, M = Ti, Zr, Hf, V, Nb, Ta, X=C, N). The interface energies have positive
values for carbides and nitrides of group IVB metals (Ti, Zr, Hf), while they have negative values for
carbides and nitrides of group VB metals (V, Nb, Ta). Influence of bond energy was estimated using
the discrete lattice plane/nearest neighbor broken bond (DLP/NNBB) model. It was found that the
dependence of interface energy on the type of carbides and nitrides was closely related to changes of
the bond energies between Fe, M and X(=C, N) atoms before and after formation of the interfaces
Fe/MX.
Dimensional Characteristics of Products Using Rotary Swaging Machine with Four-Dies
Authors: Lim Seong Joo , Choi Ho Joon , Na Kyoung Hoan , Lee C.H.
Published: March 2009

Experiments under a cold rotary swaging process have been conducted to investigate the
dimensional characteristics of the swaged tube and solid bar for obtaining proper product of desirable
quality. Dimensional characteristics are expressed in terms of dimensional deviation and surface
roughness of swaged product through the rotary swaging process. The process variables such as
forming speed and percent reduction of outer diameter of the product are considered and selected
because of playing a key role in the rotary swaging process. Furthermore the developed rotary
swaging machine with four-split dies, named as KRSM25, is used in the swaged experiment. Based
on the experimental results, it is observed that the process variables affect the quality of swaged
product such as dimensional precision, surface roughness of the product. Defect could be found to
occur at a value of more than 2.0 mm/rev in forming speed. The dimensional precision of swaged
product depends on the percentage reduction of outer diameter and forming speed. The work
presented in this paper might be used for available information in the design of the optimum rotary
swaging process.
Stable Deposition and Patterning of Metal Layers on the PDMS Substrate and Characterization for the Development of the Flexible and Implantable Micro Electrode
Authors: Baek Ju Yeoul , Kwon Gu Han , Kim Jeong Yun , Cho Jin Ho , Lee Seung Ha , Sun Kyung , Lee Sang Hoon
Published: March 2009

PDMS(polydimethylsiloxane) is a flexible and biocompatible material and is widely used
in bio- or medical-related fields. Recently, PDMS has been used as a substrate of implantable
electrodes but has exhibited limits in stable metal layer deposition and patterning. In this paper, we
have developed processes for both the stable metallization of PDMS surface and the selective
patterning of conductive elements. The surface treatment via the oxygen plasma ions significantly
affects the adhesion of metal layers to the PDMS surface, while the other factors exhibited no
significant relations. On the basis of our procedure resulted in the effective production of the stable
and fine (line width: 20 ) electrode patterns on the PDMS substrate. Finally, we fabricated
PDMS-based flexible and implantable micro electrode for the subretinal prosthesis.
X-Ray Anomalous Scattering Studies of Fe-Tb Amorphous Thin Films
Authors: Kim Chan Wook , Watanabe Yasuhiro , Nanao Susumu
Published: March 2009

In order to investigate the atomic structure of sputtered-deposited Fe76Tb24 amorphous film,
we performed X-ray anomalous scattering (XAS) measurements at two energies near the Tb
K-absorption edge using the synchrotron-radiations (SR). The total, Tb and Fe environmental pair
distribution functions (PDF's) of the amorphous film were obtained from the normalized scattering
intensities after the corrections for the structural analysis. The coordination numbers were calculated
from the area under the fitted PDF profiles multiplied by 4πr 2 and near-neighbor distances were
estimated from the positions of the peaks of the fitted profiles.
Analysis on the Martensitic Transformation in the Ti-xNb Alloys Using a Phenomenological Theory
Authors: Jeong Hi Won , Kim Seung Eon , Jo Chang Yong , Lee Yong Tae , Park Joong Kuen
Published: March 2009

The titanium alloys containing the Nb transition elements have been investigated as the
Ni-free shape memory and the biomedical alloys with a low elastic modulus. The mechanical
properties of the alloys depended upon the meta-stable phases like the α`, α``, ω. To study the
martensitic transformations from the β to α`` or α` the Ti-xNb (x=0 to 40 wt%) alloys were melted
into the button type ingots using a VAR, and followed by the water-quenching after the soaking at
1000oC for 2hrs. The crystallography of the martensitic phases in the water-quenched alloys was
analyzed using a XRD. The diffraction peaks of the orthorhombic martensites were identified by the
crystallographic relationship with the bcc matrix. The lattice parameters of the orthorhombic
martensites were varied continuously with the contents of the Nb elements. The martensitic
transformations of the alloys were studied using the phenomenological theory of Bowles and
Mackenzie.
Characterization of a-Se(As:Cl) Film for Phosphor Coupled X-Ray Light Modulators
Authors: Kang Sang Sik , Park Ji Koon , Cha Byung Youl , Shin Jung Woog , Kim So Yeong , Mun Chi Woong , Lee Kun Hwan , Lee Hyung Won , Nam Sang Hee
Published: March 2009

Amorphous selenium (a-Se) film has the potential to fulfill the requirements of a novel
x-ray image detector because of its good photo-to-dark impedance ratio, large area coverage, and low
temperature deposition. In this work were studied the structural, optical and electrical properties of
thermally- evaporated a-Se film for the phosphor-light modulator (PLM). From the x-ray diffraction
and electron microscopy experimental results, the deposited film had an amorphous phase without
any re-crystallization or defects. Also, the light absorption in widely visible range of 400 ~ 630 nm
was over 95 %. From the electrical measurements, the low dark current density of 2.8 nA/cm2 was
obtained at 10 V/㎛. The x-ray sensitivity of the 270㎛-Gd2O3:Eu phosphor coupled 20㎛-Se film
was 7.31 nC/cm2-mR. From such experimental results, the novel x-ray detector which incorporates
phosphor coupled x-ray light modulator, makes an operation at low x-ray exposure possible,
therefore, the applications as a medical imaging detector are shown below.
Grand Canonical Monte Carlo Simulations for the Prediction of Adsorption Capacity of Hydrogen in MOFs
Authors: Jung Dong Hyun , Kim Dae Jin , Lee Tae Bum , Kim Ja Heon , Choi Seung Hoon
Published: March 2009

We performed grand canonical Monte Carlo simulations on the series of MOFs, that are
Metal-Organic Frameworks having various organic linkers and nanocube frameworks, to find out
rational design and synthetic strategies toward efficient hydrogen storage materials. The adsorption
amounts of hydrogen molecules showed diverse range according to the variation of parameter
values. This indicated that the hydrogen adsorption was sensitive to the values of parameters
corresponding to the non-bonding interactions. The optimization of the parameters was done to fit
the experimental results at 77 K. After the parameterization of the potential function, we adopted
this condition to predict the adsorption amount of hydrogen molecules on IRMOF-3, which has
NH2 group as the substituent of hydrogen bonded to benzene ring. The calculation results showed
good agreement with experimental adsorptions and we analyzed the adsorption sites of each MOF
and the relationship between the adsorption characteristics and the hydrogen uptake capacity.
Measurement of Mechanical Properties for Thin Film Using Visual Image Tracing Method
Authors: Lee Sang Joo , Han Seung Woo , Kim Jae Hyun , Lee Hak Joo
Published: March 2009

It is quite difficult to accurately measure the mechanical properties of thin films. Currently,
there are several methods (or application) available for measuring mechanical properties of thin films.
Their properties, however, have been determined by indirect methods such as cantilever beam test and
diaphragm bulge test. This paper reports the efforts to develop a direct strain measurement system for
micro/nano scale thin film materials. The proposed solution is the Visual Image Tracing (VIT) strain
measurement system coupled with a micro tensile testing unit, which consists of a piezoelectric
actuator, load cell, microscope and CCD cameras. The advantage of this system is the ability to
monitor the real time images of specimen during the test in order to determine its Young’s modulus
and Poisson’s ratio at the same time. Stress-strain curve, Young’s modulus, yield strength and
Poisson’s ratio of copper thin film measured using VIT system are presented.
Nanoporous SiC Membrane Derived from Preceramic Polymer
Authors: Kim Y. , Kim Soo Ryong , Song B.G. , Dabhade Vikram V. , Sea B.K. , Kwon Woo Teck
Published: March 2009

Ceramic membranes having nano sized pores have great potential for gas separation at
high temperature due to their good thermal stability. Moreover, nanoporous silicon carbide
membrane has potential application under hydrothermal condition at high temperature. In this
research, nanoporous SiC membrane has been developed on the porous alumina plate using
preceramic polymers as CVD precursor at 850oC. The preceramic polymer was characterized with
Si29 NMR, FT-IR, GC and TGA. The prepared SiC membrane was characterized with SEM and
EDS. The hydrogen permeability and selectivity toward nitrogen gas were measured using a GC.
Chemical Vapor Deposition of Pt Nano Particles on Carbon Nanotubes
Authors: Kim Hee Yeon , Lee Seung Jae , Jung Nam Jo
Published: March 2009

Pt nano particles were synthesized on carbon nanotubes (CNTs) by chemical vapor
deposition (CVD). (Trimethyl)methylcyclopentadienyl platinum (MeCpPtMe3) was used as Pt
precursor, which was vaporized at 70oC and delivered to the pretreated CNTs at the reactor. The CVD
was performed at various temperatures, 80~270oC with various gas flows. Consequently, Pt nano
particles of 1~2 nm size were synthesized by CVD, which is much smaller than the Pt particles
prepared by wet impregnation and by electrochemical deposition. The surface characterizations of
Pt/CNT catalysts were performed by XRD, HR-TEM, CO chemisorption, etc.
Epitaxial Growth and Anisotropic Dielectric Properties of La-Doped Bi4Ti3O12 Thin Films
Authors: Lee Jang Sik , Jia Q.X.
Published: March 2009

To investigate the anisotropic dielectric properties of layer-structured bismuth-based
ferroelectrics along different crystal directions, we fabricate devices along different crystal
orientations using highly c-axis oriented Bi3.25La0.75Ti3O12 (BLT) thin films on (001) LaAlO3 (LAO)
substrates. Experimental results have shown that the dielectric properties of the BLT films are highly
anisotropic along different crystal directions. The dielectric constants (1MHz at 300 K) are 358 and
160 along [100] and [110], respectively. Dielectric nonlinearity is also detected along these crystal
directions. On the other hand, a much smaller dielectric constant and no detectable dielectric
nonlinearity in a field range of 0-200 kV/cm are observed for films along [001] when c-axis oriented
SRO is used as the bottom electrode.
Pt(IV) Adsorption Characteristics of Nanoporous Carbons Modified with Carboxymethylated Polyethyleneimine
Authors: Jung Yongju , Yeon Jei Won , Kim Ji Man , Lee Hyung Ik , Kim Seok , Park Soo Jin
Published: March 2009

In this study, we modified the surface of nanoporous carbons with carboxymethylated
polyethyleneimine (CM-PEI) of a high charge density in order to increase the Pt loading on the
nanoporous carbons in an aqueous solution. We carried out equilibrium adsorption tests of Pt(IV) on
the pure nanoporous carbon and the CM-PEI-coated carbons and evaluated the adsorption isotherm
on the CM-PEI-coated carbon using various isotherm models. It was found that the adsorption of
Pt(IV) onto the CM-PEI-coated carbons obeys the Langmuir isotherm model.
Microwave-Assisted Heterogeneous Transfer Hydrogenation of Ketones
Authors: Sarkar M.S. , Jin Myung Jong
Published: March 2009

A first and efficient procedure has been developed for microwave-assisted transfer
hydrogenation of ketones. Silica gel-supported ligand 2 has been prepared for the transfer
hydrogenation. This immobilized ligand-Ru complex acted as an efficient catalyst for the hydrogen
transfer reaction of ketones. The MW-assisted reactions using the supported ligand 2 could reach
completion within 20~40 min.
A Study of Hydroxyapatite Coating on Porous Ti Compact by Electrostatic Spray Deposition
Authors: Lee W.H. , Kim Y.H. , Oh N.H. , Cheon Y.W. , Cho Y.J. , Lee C.M. , Kim K.B. , Lee N.S.
Published: March 2009

Coatings of hydroxyapatite (HA) on the porous-surfaced Ti compact have been
conducted by electrostatic spray deposition (EDS). The precursor solution for the HA coating by
ESD was prepared by mixing nano-scaled HA powder with ethyl alcohol. As-deposited HA films on
the substrate were heat-treated (400 ~ 900 °C) and their physical characteristics were investigated
by Scanning Electronic Microscopy (SEM), X-ray Diffractometer (XRD), and X-ray
Photoelectronic Spectroscopy (XPS). As-deposited HA films were consisted of HA particles which
were uniformly distributed on the Ti substrate, showing a porous structure. By heat treatment, HA
particles were agglomerated each other and melted to form a highly dense and homogeneous
coating layer consisted of equiaxed nano-scaled grains. HA coatings on the porous-surfaced Ti
compact consisted of highly crystalline apatite phase with the Ca/P ratio of about 1.67 were
successfully obtained by using ESD.
High Quality Epitaxial Pt Films Grown on γ-Al2O3/Si (111) Substrates
Authors: Ito Mikinori , Sawada Kazuaki , Ishida Makoto
Published: March 2009

Epitaxial Pt films were grown on γ-Al2O3/Si (111) substrate by RF-magnetron sputtering.
The γ-Al2O3 buffer layers were grown epitaxially using molecular beam epitaxy. The films were
characterized by reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD) and
atomic force microscopy (AFM). The results of XRD showed that high-quality Pt films were obtained
at around 560°C. In addition, the Pt films exhibited a very smooth surface with the root-mean-square
(rms) surface roughness is about 0.4 nm.
Ferroelectric Nanotube Arrays in Hexagonally Ordered Pores of Aluminum Oxide
Authors: Bu S.D. , Choi Y.C. , Kim J. , Han J.K. , Chang K.S.
Published: March 2009

Self-organization of a two-dimensional array of nanopores, which was formed by anodic
oxidation of aluminum, was investigated quantitatively using scanning electron microscopy (SEM)
images and their fast Fourier transformation analysis. The highly ordered array of nanopores with
diameters of ~60 nm was obtained by two-step anodization at an anodizing voltage of 40 V for an
anodizing time of 36 h in a 0.3 M oxalic acid. A two-dimensional ordered array of ferroelectric
PbTiO3 nanotubes was successfully fabricated by a spin coating of sol-gel solution into porous anodic
alumina template. SEM and transmission electron microscopy images show that the nanotubes have a
relatively constant wall thickness of ~15 nm with an outer diameter of ~60 nm. The present method
has a high efficiency to fabricate an ordered nanotube array of a variety of functional metal oxide
materials in a large area.
Synthesis and Photocatalytic Activity of TiO2 Nanoparticles Loaded on the Fluorine-Modified Hydrophobic Mesoporous Silica
Authors: Yuan Shuai , Oakada Shusuke , Maki Keiichi , Kuwahara Yasutaka , Tomonari Masanori , Kawasaki Shinichi , Mori Kohsuke , Yamashita Hiromi
Published: March 2009

The fluorine-modified mesoporous silica HMS(F20) was synthesized by using the mixture
of TEFS(SiF(OC2H5)3) and TEOS(Si(OC2H5)4) as the silica source. The specific surface and pore
size distribution were characterized by N2 adsorption and the hydrophilic-hydrophobic property was
measured by water adsorption. The photocatalytic activities of TiO2 nanoparticles loaded on
HMF(F20) and HMS were investigated for the degradation of iso-butanol diluted in water. The
results show that the fluorine-modified mesoporous silica HMS(F20) has higher hydrophobic
property than HMS and the TiO2/HMS(F20) exhibits the higher photocatalytic activity than
TiO2/HMS. The hydrophobic mesopores benefit the condensation of hydrophobic organic
compounds diluted in water, which results in higher photocatalytic degradation efficiency.