Superplasticity in Advanced Materials - ICSAM 2006
Vols. 551-552
Vols. 551-552
Fundamentals of Deformation and Annealing
Vol. 550
Vol. 550
Progress in Light Metals, Aerospace Materials and Superconductors
Vols. 546-549
Vols. 546-549
Eco-Materials Processing and Design VIII
Vols. 544-545
Vols. 544-545
THERMEC 2006
Vols. 539-543
Vols. 539-543
Materials Science, Testing and Informatics III
Vols. 537-538
Vols. 537-538
Progress in Powder Metallurgy
Vols. 534-536
Vols. 534-536
Advances in Materials Manufacturing Science and Technology II
Vols. 532-533
Vols. 532-533
Advanced Powder Technology V
Vols. 530-531
Vols. 530-531
Silicon Carbide and Related Materials 2005
Vols. 527-529
Vols. 527-529
Advances in Materials Processing Technologies, 2006
Vol. 526
Vol. 526
Residual Stresses VII, ECRS7
Vols. 524-525
Vols. 524-525
High-Temperature Oxidation and Corrosion 2005
Vols. 522-523
Vols. 522-523
Progress in Powder Metallurgy
Volumes 534-536
Paper Title Page
Abstract: A hyrdrothermal reaction process has been developed to prepare rod-like crystals of
copper oxide using copper nitrate trihydrate as a function of synthesis temperature, stirring speed
and solution pH value. The properties of the fabricated crystals were studied using scanning
electron microscopy, X-ray diffraction and particle size analysis. The morphology of the
synthesized CuO was dependent on both the pH value of the solution and the morphology of the
seed materials. Synthesized particles have regular morphologies and a uniform size distribution.
77
Abstract: TiO2 nanoparticle was synthesized by the flame method using a metal organic precursor
of titanium tetraisopropoxide (TTIP, Ti(OC3H7)4), which was controlled by varying the ratio and
flow rate of gas mixtures consisting of oxygen (oxidizer), methane (fuel) and nitrogen (carrier gas).
The morphology and the size distribution of nanoparticles were observed with TEM and FESEM,
and the phase evolution was analyzed by XRD measurement using a monochromator. The
crystalline phases of TiO2 nanoparticle depended strongly on the temperature distribution in the
flame, whereas the morphology was not sensitive. During the flame synthesis of TiO2 nanoparticle,
anatase TiO2 nanoparticle was predominantly synthesized at the high flame temperature and rapid
flame cooling condition. The low flame temperature and long flame length enabled to form almost
rutile TiO2 nanoparticle (>95%). The anatase nanoparticle was formed by a homogeneous
nucleation and has finally kept the anatase phase without the phase transformation any more in the
flame. However, the rutile TiO2 nanoparticle was not formed directly and homogeneously in flame,
and was manufactured by the phase transformation such as amorphousanataserutile. It was
proved that the rutile phase was nucleated heterogeneously from the amorphous or anatase particles.
81
Abstract: Laser pyrolysis is a very suitable gas-phase process for the synthesis of a wide range of
nanoparticles at laboratory scale. The principle of the method is based on the decomposition of
gaseous or liquid reactants by a high power CO2 laser followed by a quenching effect. The literature
reports the possibility to produce carbides, nitrides, oxides, metals and composites nanoparticles by
this process. This paper reports a study of the effect of the laser intensity (using an innovative
optical system) and of the gas flow rates on the characteristics (size and structure) of silicon carbide
(SiC) nanoparticles produced at pilot scale (up to 1.13 kg/h) by using a mixture of silane (SiH4) and
acetylene (C2H2). It has been shown that the decrease of the gas flow rate favors the increase of the
mean grain size of the particles and that the increase of the laser intensity seems to provoke an
increase of the mean crystal size and/or crystal number.
85
Abstract: This works deals with the deposition of Ti-Zr-Ni icosahedral quasicrystalline powders by
low vacuum plasma spray technique and the performances of the resulting coating layers. The
microstructure of the coatings, as analyzed by X-ray diffraction and TEM techniques, consisted of
nanometer-sized W-Ti50Zr35Ni15 1/1 cubic approximant and TiZrNi Laves phases as well as a low
volume fraction of submicrometer-sized ZrO2 phase. The absence of the icosahedral phase in the
coating layers was explained by the loss of Ti during plasma spraying. The shift in the composition
and the presence of the ZrO2 phase within the coating layers are believed to be responsible for the
reduced microhardness and corrosion performances evaluated by electrochemical tests in a Hanks’
Balance Salt Solution at 37oC.
89
Abstract: The reaction-sintered alumina ceramics with low firing shrinkage were prepared from
Al/Al2O3 powder mixture by attrition milling and the effect of milling characteristics of raw
powders on reaction sintering was investigated. Powder mixtures of flaky shape Al with coarse
alumina was much more effectively comminuted by the attrition milling than the mixtures of
globular shape Al with coarse alumina powders. Furthermore the coarse alumina was much more
useful in pulverizing and grinding the ductile Al particles than fine alumina.
After attrition milling and isopressing at 400MPa, the Al/Al2O3 specimen was oxidized at 1200°C
for 8 hours followed by sintering at 1550°C for 3 hours. Because mixed powder of coarse alumina
with flaky Al was much more effectively comminuted than the globular Al, sintered body of more
than 97% theoretical density was achieved, but low contents of Al leads to relatively higher
shrinkage of about 8%. As the coarse alumina particles are much more useful in cutting and
reducing the ductile Al particles, the use of the coarse alumina powder was much more effective in
reaction-sintering.
93
Abstract: Novel bisphenol-based wholly aromatic sulfonated poly(ether sulfone-ketone) copolymer
and organic-inorganic composite membranes were prepared for operation 80°C in polymer
electrolyte membrane fuel cell (PEMFCs). The copolymer were synthesized by direct aromatic
nucleophilic substitution polycondensation of 4,4-difluorobenzophenone, 2,2’-disodiumsulfonyl-
4,4’-fluorophenylsulfone (40mole% of bisphenol A) and bisphenol A. Polymerization proceeded
quantitatively to high molecular weight in N-methyl-2-pyrrolidinone at 180°C. Organic-inorganic
composite membranes were obtained by mixing organic polymers with hydrophilic SiO2 obtained
by sol-gel process. The polymer and a series of composite membranes were studied by FT-IR,
1HNMR, differential scanning calorimetry (DSC) and thermal stability. The proton conductivity as
a function of temperature decreased as SiO2 content increased, but methanol permeability
decreased. The nano composite membranes were found to poses all requisite properties; Ion
exchange capacity (1.2meq./g), glass transition temperatures (164-183), and low affinity towards
methanol (4.63-1.08x10-7 cm2/S).
97
Abstract: The particle size distribution is one of the important parameters for characterisation of
quality of metal powders. Specific material properties such as ability to flow, reactivity as well as
compressibility and its hardening potentials – hence the most important characteristics of sintered
metals - are determined by the size distribution. The correct particle size distribution is the key to
best product quality in atomisation processes of aluminium, milling of pure metals and other
processes.
101
Abstract: The Ag/TiO2-xNx nanoparticles were synthesized by photochemical deposition with
irradiation of visible light in a TiO2-XNX suspension system. The prepared products were
characterized by means of XRD, Uv-vis, and FEM. Its photocatalytic activity was investigated by
the decomposition of methylene blue (MB) solution under illumination of visible and ultraviolet
light, respectively. Compared to TiO2-xNx, the photocatalytic activity of as–prepared Ag/TiO2-xNx is
obviously enhanced due to the decreasing recombination of a photoexcited electron-hole pair. The
mechanism in which photocatalytic activity is enhanced is discussed in detail.
105
Abstract: Monodispersed and nano-sized Cu powders were synthesized from copper sulfate
pentahydrate (CuSO4ㆍ5H2O) inside a nonionic polymer matrix by using wet chemical reduction
process. The sucrose was used as a nonionic polymer network source. The influences of a nonionic
polymer matrix on the particle size of the prepared Cu powders were characterized by means of Xray
diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis (PSA). The
smallen Cu powders with size of approximately 100㎚ was obtained with adding of 0.04M sucrose
at reaction temperature of 60°C. The particle size of the Cu powders prepared by the reduction
inside polymer network was strongly dependent of the sucrose content and reaction temperature.
109
Abstract: Monosized germanium micro particles are prepared by a newly developed Pulsated
Orifice Ejection Method (POEM). The obtained particles are categorized into two kinds of the
microstructures as refined and coarse ones. The morphological difference is estimated to be
determined by the undercooling level during nucleation. Actually, the increase in the temperature of
the melt was effective in coarsening the microstructure, because the temperature of the melt
intensely relates to the undercooling level. The transition temperature of coarse and refined
microstructures is found to be 1300-1350K. Furthermore, a triggered nucleation could improve the
crystallinity of the particles in the short separation.
113