bluuebunny/crossref_metadata_2025 huggingface dataset:
Time-Economic Lifetime Assessment for High Performance Thermal Barrier Coating Systems
Authors: Bartsch Marion , Baufeld Bernd , Dalkilic S. , Mircea Iulian , Lambrinou K. , Leist T. , Yan J. , Karlsson Anette M.
Published: March 2009

Strategies for time-economic lifetime assessment of thermal barrier coatings (TBC) in
service are described and discussed on the basis of experimental results, achieved on material
systems with coatings applied by electron beam physical vapour deposition. Service cycles for gas
turbine blades have been simulated on specimens in thermo-mechanical fatigue tests, accelerating
the fatigue processes by an increase of load frequency. Time dependent changes in the material
system were imposed by a separate ageing, where the samples were pre-oxidized prior to the fatigue
test. Results of thermo-mechanical fatigue tests on pre-aged and as-coated specimens gave evidence
of interaction between fatigue and ageing processes. An alternative approach is used, which is
focused on the evolution of a failure relevant damage parameter in the TBC system. The interfacial
fracture toughness was selected as a damage parameter, since one important failure mode of TBCs
is the spallation near the interface between the metal and the ceramic. Fracture mechanical
experiments based on indentation methods have been evaluated for monitoring the evolution of the
interfacial fracture toughness as a function of ageing time. It was found that the test results were
influenced by both changes of the interface (which is critical in service) and changes in the
surrounding material.
Microstructural Evolution of Thermal Barrier Coatings during Isothermal Oxidation
Authors: Salazar Alicia , Gómez-García J. , Poza P. , Utrilla V.
Published: March 2009

This paper analyses the degradation of a ceramic top coating 70%ZrO2 – 30%CaO
deposited onto a stainless steel AISI 304 by thermal spray, using Ni-6%Al-5%Mo as overlay
coating. These thermal barrier coatings were heat treated for 48, 120 and 288 h at 800 °C to evaluate
the degradation of these materials by isothermal oxidation. The microstructure evolution during
oxidation was analysed by environmental scanning electron microscopy, transmission electron
microscopy and X ray microanalysis. A thermally grown oxide layer was observed between the
overlay coating and the ceramic top coating after oxidation. This layer was formed by a mixed Al,
Ni and Mo oxides.
Laminated and Functionally Graded Ceramics by Electrophoretic Deposition
Authors: Van der Biest Omer , Vandeperre L. , Put Stijn , Anné Guy , Vleugels Jef
Published: March 2009

Electrophoresis is the effect that when an electric field is applied to a suspension of a powder in a liquid, the powder particles move under influence of this field. Frequently the powder particles also deposit at one of the electrodes. The form of the electrode determines the form of the deposit, hence shaping is possible. The current insights into the science and technology of electrophoretic deposition (EPD) will be summarized. EPD is well suited for shaping layered microstructures (laminates), by simply changing repeatedly between two or more suspensions during deposition. Tubular laminates consisting of silicon carbide layers and crack deflecting graphite interlayers have been produced. These tubes demonstrate an enhanced fracture energy and a gradual mode of failure. Another area of advanced ceramics where the use of EPD makes sense are functionally graded materials (FGM) in which one tries to combine in one component high hardness and high toughness. EPD allows the formation of FGM by depositing from a powder suspension to which a second suspension is continuously added during the process. An example will be shown of a graded WC-Co hardmetal.
Poly(lactic acid) Composites Directly Molded from Lactide and Particle Fillers
Authors: Funabashi Masahiro , Inuzuka Yoshifumi , Kunioka Masao
Published: March 2009

Polymer composite samples consisting of L-Lactic acid (LA) was reacted by ring-opening
polymerization with aluminum triflate as a catalyst, glycerol as an initiator and various particles as
fillers. Cellulose particles, kaolin and silica gel with different particle sizes were employed as fillers.
Filler content was varied 0 to 100 wt% as ratio of filler weight to PLA weight. L-Lactide (L-LA),
aluminum triflate as catalyst, glycerol as an initiator and particles were mixed at room temperature
and then were put into plastic tubes. The mixture in tubes was heated and reacted at 100 oC for 6
hours. The samples were removed from tubes after cooling and were cut into the column shape
specimen with diameter of 10 mm and ca. 10 mm height. By the above procedure, particles could be
mixed to poly(lactic acid) (PLA) matrix easily and homogeneously. The molecular weight and
molecular weight distribution of PLA matrix were determined by gel permeation chromatography
(GPC). Apparent density of composite samples was calculated by using weight and sizes of column
shape specimens. The mechanical properties such as elastic modulus and strength were investigated
by compression tests using column shape specimens. Molecular weight and molecular weight
distribution were almost constant for all the samples with and without particles. Elastic modulus and
compression strength were improved by particles. For the cellulose particles filled samples, the
highest values of elastic modulus and compression strength were derived at filler content of around 20
vol%. The influences of sizes and types of particles on the physical properties such as molecular
weight, density and mechanical properties were investigated.
Fe3O4/Polyaniline Nanoparticles with Core-Shell Structure and their Inductive Heating Property in AC Magnetic Field
Authors: Zhao Dong Lin , Zeng Xian Wei , Xia Qi Sheng , Tang Jin Tian
Published: March 2009

The magnetite (Fe3O4) nanoparticles were prepared by coprecipitation of Fe3+ and Fe2+ with
aqueous NaOH solution. The Fe3O4/polyaniline (PANI) magnetic composite nanoparticles with
core-shell structure with diameter of 30-50 nm were prepared via an in-situ polymerization of
aniline in aqueous solution containing Fe3O4 magnetic fluid. The inductive heat property of
Fe3O4/polyaniline composite nanoparticles in an alternating current (AC) magnetic field was
investigated. The potential of Fe3O4/polyaniline nanoparticles was evaluated for localized
hyperthermia treatment of cancers. The saturation magnetization Ms and coercivity Hc of Fe3O4
nanoparticles are 50.05 emu/g and 137 Oe respectively, the Fe3O4/polyaniline composite
nanoparticles, 26.34 emu/g and 0 Oe. Exposed in the alternating current (AC) magnetic field for 29
min, the temperatures of physiological saline suspension containing Fe3O4 nanoparticles or
Fe3O4/polyaniline composite nanoparticles are 63.6 °C and 52.4 °C respectively. The
Fe3O4/polyaniline composite nanoparticles would be useful as good thermoseeds for localized
hyperthermia treatment of cancers.
Numerical and Experimental Studies on Cured Shape of Thin Unsymmetric Carbon/Epoxy Laminates
Authors: Dai Fu Hong , Zhang Bo Ming , He Xiao Dong , Du Shan Yi
Published: March 2009

An analytical model was established by means of Ritz method to calculate the cured
shape of cross-ply unsymmetric composite laminates. A number of experiments of Carbon/Epoxy
laminates were conducted. It was found in the experiment that the warped surface could be a
multiple-value function, which should be studied further. The result of calculation correlates well
with the experimental result except the regions very near the laminate edge. The conclusion is
instructive to manufacture of composite laminates.
Application of a Complete Tooling Force Analysis for Simulation of Liquid Composite Moulding Processes
Authors: Bickerton S. , Kelly Piaras
Published: March 2009

The term Liquid Composite Moulding (LCM) encompasses a growing list of composite
manufacturing processes. The focus of this paper is prediction of tooling forces for Resin Transfer
Moulding (RTM). Previous experimental work has demonstrated the influence of reinforcement
compaction behaviour, which is strongly non-elastic. A viscoelastic compaction model has been
developed which addresses both dry and wet response, and is implemented in RTM simulations of
simple flat parts. Non-planar geometries introduce a tangential stress acting on mould surfaces, due to
shear of the reinforcement. The tooling force analysis is extended to complex parts using an existing
RTM filling simulation, LIMS, which has been developed at the University of Delaware.
Microfibril-Reinforced Composites from PE/PET Blends: Effect of Reinforcement Size on Oxygen Permeability
Authors: Shields R.J. , Bhattacharyya Debes , Fakirov S.
Published: March 2009

The objective of this study was to manufacture and investigate the properties of barrier
films made from microfibril-reinforced polymer composites (MFCs) based on blends of linear low
density polyethylene (PE) and poly(ethylene terephthalate) (PET). Blends containing 30 wt% of
PET were prepared and extruded into strands. These were then subjected to cold drawing and
compression moulded into thin films. The permeability of the films to oxygen gas was measured
using a permeation test chamber and the effect of the draw ratio on the size of the reinforcing fibrils
was also observed. Scanning electron microscope (SEM) revealed substantial differences in the
structures of neat and MFC films. A model developed for predicting the permeability of filled
polymer composite films was modified and compared to the test results. The draw ratios of the
MFCs did not appear to have a significant effect on oxygen permeation, despite altering the
dimensions of the reinforcing fibrils. The MFC films were found to be half as permeable as the neat
polymer films.
Multi-Scale Analysis for Thermo-Elasticity Properties of Composite Materials with Small Periodic Configuration
Authors: Tang Shao Fan , Huang Fu Hua , Liang Jun , Du Shan Yi
Published: March 2009

In this paper, based on the equations of coupled thermo-elasticity, two-scale asymptotic
expressions of the temperature and displacement of composite materials under coupled
thermo-elasticity condition are set up with the perturbation method. By the multi-scale finite element
method, the temperature and 2-order displacement, strain and stress of composite materials with
small periodic configuration under coupled thermo-elasticity condition are calculated. Comparing
with the results calculated by finite element method with refined meshes, it’s shown that multi-scale
method is an efficient method, and the calculation precision is satisfied.
Preparation of Carbon Nanotube Reinforced Epoxy Resin Coating and its Microwave Characteristics
Authors: Zhao Dong Lin , Chi Wei Dong , Shen Zeng Min
Published: March 2009

The carbon nanotubes were prepared by catalytic decompose of benzene using floating
transition method at 1100~1200°C. Benzene was used as carbon source and iron as catalyst with
sulfur. The carbon nanotubes are straight with diameter 30~80nm, internal diameter 10~50nm and
length 50~100μm. The carbon nanotubes and epoxy resin were sufficiently mixed. The mixture
was smeared on to a pure aluminum plate layer by layer until the thickness of the composite layer
reached 1.0 mm. The coating resin was cured by heating under infrared radiation. Complex
permittivity, permeability and microwave reflectivity of carbon nanotubes reinforced epoxy resin
coating had been investigated at the frequency ranges of 8.2~12.4GHz and 2~18GHz respectively.
The real part (ε′) of complex permittivity of this coating ranges from 14.87 to 13.86, and the
imaginary part (ε″), from 6.42 to 5.87, the loss tangent tgδε (ε″/ε′), from 0.42 to 0.45. The real part
(μ′) of complex permeability of this coating ranges from 1.02 to 1.14, and the imaginary part (μ″),
from 0.08 to 0.11, the loss tangent tgδμ (μ″/μ′), from 0.06 to 0.11. The maximum absorbing peak of
the carbon nanotube reinforced epoxy resin coating is 22.89 dB at 11.40GHz. The band width
(R<-10dB) of this coating with thickness of 1.0 mm is 3.0GHz, band width (R<-5dB) is 4.7GHz at
the frequency range of 8~18GHz. This carbon nanotube reinforced epoxy resin coating would be a
good candidate for microwave absorbing material.
Processing, Properties and Possible Applications of PZT-Based Thin Films
Authors: Czekaj Dionizy
Published: March 2009

The radio frequency (RF) sputtering method was utilized to grow PZT-based ferroelectric thin
films with the chemical composition Pb(Zr0.53Ti0.45W0.01Cd0.01O3). The thin films were characterized in
terms of their microstructure, crystalline structure, chemical composition and dielectric properties. The
processing conditions diagram was defined, which ensured conservation of stoichiometry of the chemical
composition of the thin films. Complex impedance spectroscopy was used to measure frequencydependent
dielectric properties of the PZT-type thin films. Great application potential of the PZT-based
thin films was considered and possibility to employ as-obtained PZT thin films as active elements of the
piezoelectric sensors was reported.
Influence of Different Dopants on the Piezoelectric Properties of the Na1/2Bi1/2TiO3-BaTiO3- Lead-Free Ceramics
Authors: Zhao Wei , Zhou He Ping , Yan Yong Ke , Liu Dan , Liu Shan Shan
Published: March 2009

Lead-free Na1/2Bi1/2TiO3-6BaTiO3 (BNT-6BT) ceramics with different dopants were prepared by a conventional ceramic fabrication technique. The influence of doping CeO2, La2O3, Nb2O5 and Co2O3 on the structure was studied, and the mechanism of soft and hard additives with A-site or B-site substitute changing the piezoelectric properties was discussed. It was found that the rhombohedral-tetragonal morphotropic phase boundary (MPB) of the Na1/2Bi1/2TiO3-6BaTiO3 was not changed obviously.
Liquid Phase Sintering of α-Si3N4 by Spark Plasma Sintering
Authors: Yan Fa Qiang , Chen Fei , Shen Qiang , Zhang Lian Meng
Published: March 2009

In this study, spark plasma sintering (SPS) was applied to prepare α-Si3N4 ceramics of different
densities with magnesia, silicon dioxide, alumina as the sintering aids. The sintering behavior and liquid
phase sintering (LPS) mechanism were discussed and the factors influencing the density of the prepared
samples were analyzed. Microstructures of sintered samples were observed and the phase compositions
were analyzed. The results showed that α-Si3N4 ceramics can be sintered by SPS based on the reaction
among α-Si3N4 and sintering additives which lead to the liquid phase and the density can be well
controlled from 2.48 to 3.09 g/cm3 while the content of the sintering aids changes from 10% to 28.5% and
sintering temperature from 1400°C to 1500°C.
Preparation and Characterization of ZrO2 Microspheres by Internal Gelation Process
Authors: Zhu Hong Long , Ma Ya Lu , Zhang Yu
Published: March 2009

A new process of internal gelation for preparing stabilized zirconia ceramic microspheres was
developed. The influences of process parameters such as process temperatures, raw material
concentrations, and the conditions of drying and calcining on the process and characteristics of the
microspheres were investigated in this paper. With Y2O3 and/or MgO as stabilized agents, the
microspheres had the characteristics of TZP or PSZ materials confirmed by XRD and SEM observations.
Homogeneity of Aqueous Al2O3/3Y-TZP Feedstock by Plastic Kneading
Authors: Weng Ming Tsung , Wei Wen Cheng J.
Published: March 2009

The effects of different kneading sequences, chemical additives, and solid loadings to the
homogeneity and rheological behavior of the Al2O3/3Y-TZP (ZTA) feedstock were investigated. The
properties of the feedstock were analyzed by the torque rheometry, transmission optical microscopy (OM)
and scanning and transmission electron microscopy (SEM & TEM). The optimal kneading process was
determined when good homogeneity was reached. The concepts of critical solid loading and the
homogeneity of two-oxide systems, and the power consumption to reach best microstructure will be
introduced and quantitatively analyzed.
Structural Characterization, Crosslinking and Pyrolysis Investigation of Carbosilane Oligomers
Authors: Hu Hai Feng , Wang Qi Kun , Qi Gon Jin , Chen Zhao Hui , He Xin Bo
Published: March 2009

Carbosilanes synthesized from high-pressure treatment of polysilane, were fractional distilled
and separated. Carbosilanes, characterized by IR and 1HNMR measurement, are composed of linear and
cyclic carbosilanes with some Si-H end groups. Crosslinking occurred between carbosilanes and divinyl
benzene and gave gel content of 52%, and further ceramic yield of 36% upon pyrolysis at 1200°C. The
pyrolyzates contain microcrystal SiC and free carbon, which was approved by XRD measurement.
Advanced Engineering Ceramics for Semiconductor Package Technology
Authors: Kim Hee Seung , Seo Mi Young , Kim Ik Jin
Published: March 2009

Advanced engineering ceramic technology has very remarkable reputation in the high-tech fields such as semiconductor device manufacturing. ZTA (Zirconia Toughened Alumina), ruby and alumina is applied in the manufacturing of the capillaries that demonstrate high strength, fracture toughness and long life. The advantages of the new composite material over the standard ultra-fine grain high-density material have been proven in many applications especially for packages requiring less than 50μm capillary tip diameter. In this work, micro-structural evolution of ceramic composites and its correlation with important criteria in the selection of the suitable capillary material either ZTA composites or high-density ruby ceramics for a specific package applications will be discussed.
Low Temperature Degradation of Yttria Stabilized Zirconia
Authors: Lu Zheng Lan , Jiang Dan Yu , Hu Lei , Zhu Guo Qiang , Li Qiang , Zhang Cheng
Published: March 2009

This paper explores the effects of dopant content on the aging behavior of tetragonal zirconia
polycrystal (TZP). TZP powders with varying Y2O3 content (1.75-3mol%) were synthesized by co-precipitation.
After the green body of as-prepared TZP powders being isostatically pressed at 200 MPa and
sintered at 14000C for 3 h in air, a range of TZP ceramics were fabricated. As-synthesized TZP ceramics
annealed at relatively low temperatures with the presence of water or water vapor. XRD analysis was
conducted for phase identification and determined a tetragonal to monoclinic transformation. Microscope
imaging displayed the changes of aged TZP surface structure. It is believed that the degradation of TZP
might be caused by the reaction between Y2O3 and H2O. The mechanism of low temperature degradation
of TZP was discussed.
Novel Visible-Band Transparent Ceramic Laser Material Mn:MgAl2O4
Authors: Lu Tie Cheng , Wang Xue Jun , Cheng Bing Xun , Hu Qiang , Dun Shao Bo
Published: March 2009

In this paper, transparent ceramics Mn:MgAl2O4, which are potentially applicable in visibleband
laser field, were prepared and their light transmission and photoluminescence properties were
investigated. In experiment, Mn:MgAl2O4 powders with two kinds of doping concentrations of 0.5 and
1.0 at% were synthesized through a high-temperature calcination method with NH4Al(SO4)2·12H2O and
MgSO4·7H2O as raw materials, and with MnSO4·H2O as dopant. Transparent ceramics Mn:MgAl2O4
were prepared through vacuum hot-pressing sintering at 1750oC for 1 h, and subsequent vacuumannealing
at 1700oC for 2 h. The samples were measured by means of light transmission and photoluminescence.
The results show that transparent ceramics Mn:MgAl2O4 can be prepared by a low-cost powder
technique and vacuum hot-pressing sintering. Two channels of visible-band luminescence, one peak
around 520nm and one wideband centered at 650nm, respectively, can be shown. The intensity of their
luminescence increases with increasing doping concentration. Obviously, it possesses a potential
application in the field of visible-band solid tunable laser material with high doping concentration.
Microstructure of Pyrolytic Carbon Matrix in Carbon/Carbon Composites after Graphitization
Authors: Sun Wan Chang , Li He Jun , Zhang Shou Yang , Huang Yong
Published: March 2009

The morphologies and textures of the pyrolytic carbon matrix in 2D-C/C composites after
graphitization were investigated by means of polarized light microscope (PLM) and high resolution
transmission electron microscope (HRTEM). The microstructure parameters of the pyrolytic carbon
matrix before and after graphitization were characterized with X-ray diffraction (XRD) technology. It was
found that the interplanar distance of (002) planes (d002) of pyrolytic carbon matrix decreases, and the
microcrystalline stack height (LC) increases after graphitization. Graphitization treatment resulted in a
coarsening of the surface texture and in the formation of circumferential cracks within the matrix. The
lattice fringes of the pyrolytic carbon matrix are continuous and longer in each domain and the (002) peak
spot is smaller and more intense after graphitization.
Influence of Fabricated Process on Mechanical Properties of Porous SiC-Particle/Si3N4 Composites
Authors: Wang Hong Jie , Zhang Wen , Bai Yu , Qiao Guan Jun , Gao Ji Qiang , Jin Zhi Hao
Published: March 2009

In this paper, the mechanical properties of porous Si3N4/SiC composite prepared by different
forming method (uniaxial pressing and gel-casting) were compared. Using gelcasting and two steps
sintering technology, the porous SiC-particle/Si3N4 composites with a high strength, uniform structure
and a relative high porosity were obtained by adding a little amount of nano carbon in slurry. The flexural
strength of optimized material reaches to 100MPa and its porosity is more than 60%. But using uniaxial
pressing and sintering at N2 atmosphere, because the green bodies have the high density, and the density
distribution of a powder compact was not uniform, the flexural strength is not high, and at the same time,
the microstructure is not uniform also.
Steel-Bonded Cemented Carbide GT35 by In Situ Reduction of Natural Ilmenite
Authors: Wu Yi , Yin Chuan Qiang , Zou Zheng Guang , Li Xiao Min , Shen Yu Fang , Zhou Lang
Published: March 2009

Steel-bonded cemented carbide GT35 was fabricated from natural ilmenite by in-situ synthesis
and vacuum pressureless sintering. The thermodynamics of the synthesis process were analyzed. The
results indicated that the stable phases were TiC and iron in the FeTiO3-C system. During the synthesis
process, ilmenite was reduced by graphite via a series of titanium oxides to obtain hard phase (TiC) and
the steel matrix as the ultimate products. The experimental results shown that GT35 had a reasonable
phase composition and fine TiC particles embedded uniformly in the steel matrixes. The composites
exhibited excellent mechanical properties: the relative density was higher than 97%, the hardness reached
HRC 61.5 and the maximal bending strength was about 1270MPa.
Fabrication of TiC Particles Reinforced Hadfield Steel Matrix Composite and its Wear-Resistance
Authors: Cheng Xiao Le , Gao Yi Min , Xing Jian Dong , Tan Min , Zhang Guo Shang , Zhi Xiao Hui
Published: March 2009

The TiC particles are selected as reinforced phase and the Hadfield steel as matrix. The powder
metallurgy liquid phase sintering technique is adopted to fabricate TiC particles reinforced Hadfield steel
matrix composites. The effects of elements Mo and Ni on the performance of the composites were studied.
The impact wear tester is adopted to investigate the wear-resistant property of the composites under the
different impact loads. Adding Mo can improve the interfacial bonding between the Hadfield steel and
TiC, and the best adding ratio between Mo and TiC is 1:3.68. Adding 2%(vol.%)Ni can significantly
improve the density and hardness of the composites. The experiment results of impact wear tests show
that under the condition of low and middling loads, the composites display the best wear-resistant
properties, moreover, the more TiC content is, the better wear-resistance property is. Under 2.0J impact
energy, the wear resistance of the composite containing 40%(vol.%) TiC is 1.3 times of Hadfield steel.
Solution Behavior of CaO-MgO-SiO2 System Bio-Soluble Refractory Ceramic Fibers
Authors: Wang Xi Tang , Luo Chen Ze , Zhang Bao Guo
Published: March 2009

In order to assess the behavior of ceramic fibers that are respired and accumulate in the lung,
the solubility of bio-soluble CaO-MgO-SiO2 system ceramic fibers was determined by measuring the
concentrations of the main components in the Gamble solution after different solution periods. The effect
of ZrO2, TiO2, B2O3, Al2O3 and the different CaO/MgO ratio of fibers on the solubility of the ceramic
fibers were investigated. The results indicated that the pH value of the Gamble solutions increase with the
increasing of solution time. CaO, MgO, SiO2 in the ceramic fiber have greater solubility. The existence of
ZrO2 and Al2O3 in the fibers would reduce the solubility of the fibers, and the existence of TiO2, and B2O3
in fibers will benefit the solubility of the fibers.
Effect of Reaction Conditions on Pore Configuration and Mechanical Property for Porous Hydroxyapatite Prepared by Polymer Sponge Method
Authors: Min Sang Ho , Jin Hyeong Ho , Jun B.S. , Park Ik Min , Park Hong Chae , Yoon Seog Young
Published: March 2009

Porous HAp scaffolds have been prepared by using the slurry including HAp and magnesia based on the replication of polymer sponge substrate. The influence of HAp and MgO content in slurry on the pore morphology and size, and density, porosity, and mechanical strength of porous HAp scaffolds was investigated. The obtained scaffolds with average pore sizes ranging 150 to 300 μm had open, relatively uniform, and interconnected porous structure regardless of HAp and MgO content. As the MgO content increased, the pore network frame of scaffolds became to be relatively stronger, even though the pore size was not much changed. The compressive strength of the scaffolds increased rapidly with the increase of MgO content at a fixed HAp content because of increasing the pore wall thickness and density of the scaffolds. As a result, the porosity, density, and compressive strength of the porous HAp scaffolds scaffolds prepared by the sponge method were significantly affected by the addition of MgO.
Porous Hydroxyapatite Bioceramics Prepared by Polymeric Sponge Impregnation Process
Authors: Lv Ying , Li Mu Qin , Yang Han Song , Li Xiao Jie
Published: March 2009

Porous hydroxyapatite bioceramics were obtained by impregnating the polyurethane sponge
with rheologically optimized slurry. 6wt% bioglass was doped into hydroxyapatite to act as a sintering
additive. Thermal analysis was used to study the pyrolysis process of the polyurethane sponge. Phase
component and surface morphology were characterized by X-ray diffraction and scanning electron
microscopy, respectively. It was found that hydroxyapatite was the main phase composition of the porous
ceramics sintered at 1250°C. The porous bodies prepared had an open, uniform and interconnected
structure with pore size of 200-400μm. The porous ceramics possessed high porosity of 70-80% and
compressive strength of 2.3MPa. The precipitates formed on the surface of the porous ceramics might be
bone-like apatite after immersion in a simulated body fluid for various periods.
Self-Setting Biphase Porous Calcium Phosphate Cement
Authors: Pan Jian , Tian Jie Mo , Dong Li Min , Wang Chen , Zan Qing Feng
Published: March 2009

This work has achieved a novel self-setting biphase porous calcium phosphate cement (CPC).
This biphase porous CPC is mainly formed by α-tricalcium phosphate (α-TCP) and β-tricalcium
phosphate (β-TCP). The influence of the weight percent (wt%) of β-TCP of the powder was studied. The
setting time is mainly 10-30min, and increasing with the weight percent of β-TCP. Powder ray diffraction
(XRD) analysis showed that most α-TCP have turned to low-crystallinized HA after immersed in
Simulated Body Fluid (SBF) of 37°C for 7 days. SEM observation showed that the resultants are mainly
formed with micropores and microcrystallites, and more micropores turned out in cements with more
β-TCP after immersed in SBF for 8 weeks.
Improvement of Biocompatibility and Osteointegration of Zirconia Implants by Means of Bioactive Glass Coating: An Experimental Study in Animal
Authors: Yang D.W. , Zhu J.W. , Wu W.G.
Published: March 2009

The present work aimed to evaluate the biological properties between the bioglass coated and
uncoated zirconia implants. A total of 24 implants were retrieved. Bioglass coated and uncoated porous
implants were implanted in the mandible of 4 dogs. At the experimental times of 4 and 8 weeks after
sacrifice, the histological sections specimens of the implants and surrounding tissues were processed to
determine the osteointegration rate; The other corresponding implants were processed for SEM
microanalysis. A significantly higher affinity index was demonstrated in vivo by histomorphometric
evaluation in coated versus uncoated implants. The osteointegration rates varied between 21.5% and
47.7% (cancellous bone), and between 28.0% and 56.8% (cortical bone). (p < 0.05). SEM analysis
demonstrated better bone adhesion to the material in coated implant at any weeks. Coated implants are
highly biocompatible and osteoconductive.
Bioactive Ceramics - New Processing Technologies for Immobilization of Microorganisms for Filtration and Bioreactor Applications
Authors: Koch Dietmar , Soltmann Christian , Grathwohl Georg
Published: March 2009

The metabolism of biocomponents and microorganisms is widely used for the production of medical products as well as for biotechnological processes. The productivity of the related reactions can be improved by the immobilization of the living species in granules or in a gel matrix. Since these structures can suffer during operation due to their weakness a new type of porous ceramic composites was developed where the biological phase is immobilized in a rigid inorganic matrix of high permeability for fluids. During the so-called freeze gelation process (FGP) both, a highly efficient immobilization of the biocomponents and an ideal permeability is achieved. A high versatility is then offered due to the particular advantages of the freezing step necessary for the sol-gel transition and the preservation of embedded microorganisms. While the freezing conditions are decisive for the resulting porosity of the biocer, they are also crucial for the survival rate of the embedded biocomponents. The porosity can be adjusted over a wide range by controlling the composition and the freezing conditions. By the directional ice crystal growth large pore channels can be achieved inside the biocers. Thus, the embedded biocomponents are easily accessible by external reagents and biochemical reactions can proceed with a high rate. Furthermore, cell division is conceivable inside the biocers by safe immobilization at the same time. These biocers allow a wide field of applications depending on the class of immobilized biospecies. Biocatalysis with enzymes can also be applied as bioaccumulation and absorption/desorption of metal ions for separation processes of contaminated water or highly selective filters for metallic complexes in solution.
Biomimetic Synthesis of PEC-HA Composite Analogous to Bone
Authors: Li Quan Li , Chen Zhi Qing , Darvell Brian W. , Zeng Quan , Li Gang , Ou Guo Min , Wu Ming Yue
Published: March 2009

A polyelectrolyte complex (PEC) composed of chitosan (CS) and phosphorylated chitosan (PCS) was used to encapsulate a calcium phosphate by a biomimetic method. An acidic CS (polycation) solution containing calcium and phosphate ions (Ca2+: 6mM, Ca/P = 1.67) was added into PCS (polyanion) solution leading to the formation of a polyelectrolyte complex (PEC) with nanoscopic carbonate-containing, low-crystallinity hydroxyapatite (HA) distributed evenly in the fibrils of the PEC by controlled crystal growth. The resulting composite material, PEC-HA, has a complicated, hierarchical porous structure that is expected to have high bio-compatibity and that may be of use as a carrier for controlled-release therapetic agents.
Epitaxial Growth and Electrical Characterization of PBZT Thin Films by RF Magnetron Sputtering Deposition
Authors: Fan Hui Qing , Liu Lai Jun , Chen Xiu Li , Zhang Jie , Wang Wei
Published: March 2009

Barium modified lead zirconate titanate (PBZT) thin films were grown epitaxially on Pt/Ti/SiO2/Si substrates by radio-frequency magnetron sputtering deposition and characterized by X-ray diffraction and scanning electron microscopy. Depending on the growth condition, a wide variation of crystal structure and morphology was evolved in PBZT thin films. The formation of phase structure and pyrochlore phase was strongly dependent on the oxygen partial pressure and re-evaporation of lead from the films during the deposition. Perovskite films were obtained by optimizing the deposition conditions and analyzed by the ferroelectric hysteresis (P~E).
Cyclic Oxidation Behavior of Thermal Barrier Coatings in Environments Containing Water Vapor
Authors: Wang Chang Liang , Zhou Chun Gen , Gong Sheng Kai , Xu Hui Bin
Published: March 2009

The cyclic oxidation of thermal barrier coating (TBC) specimens consisting of nickel-base
superalloy, low pressure plasma sprayed Ni-24Cr-6Al-0.7Y (wt.%) bond coatings and air plasma sprayed
7.5 wt.% yttria stabilized zirconia top coatings was studied at 1050°C in air, (air + 5%H2O), O2 and (O2 +
5%H2O) respectively. The oxidation kinetics of the TBC in each test environment accords with parabolic
law at the initial stage and obeys almost liner law at the final stage. The cyclic oxidation life of the TBC is
500h (1h/cyc) in O2 and (O2 + 5%H2O) and 900 h in air and (air + 5%H2O). The SEM observations
indicated the oxide formed along the bond coat and top coat interface after failure at 1050°C in different
environments are all consisted of Al2O3, Ni(Al,Cr)2O4, NiO and Cr2O3.
Development and Characterization of Nano-TiO2/HA Composite Bioceramic Coating on Titanium Surface
Authors: He Gang , Deng Xia , Cen Yuan Kun , Li Xiao Yu , Luo En , Nie Rong Rong , Zhao Yong , Liang Zhi Hong , Chen Zhi Qing
Published: March 2009

This research is aimed at the development and characterization of a novel bioceramic coating on the surface of pure titanium. Nano-TiO2/HA composite bioceramic coating was designed and developed on the surfaces of pure titanium discs by sol-gel route. The TiO2 anatase bioceramic coating was employed as the inner layer, which could adhere tightly to the titanium substrate. The porous HA bioceramic coating was employed as the outer layer, which has higher solubility and better short term bioactivity. Conventional HA coatings and commercially pure titanium (cpTi) were taken as control. XRD and SEM were employed to characterize the crystallization, surface morphology and thickness of the coatings. The bioactivities of the coatings were evaluated by the in vitro osteoblasts culture. Results show the nano-TiO2/HA composite bioceramic coating has good crystallization and homogeneous, nano-scale surface morphology. And it adheres tightly to the substrate. The in vitro osteoblasts culture exhibits satisfactory bioactivity.
Structuration and Fabrication of Sensors Based on LTCC (Low Temperature Co-Fired Ceramic) Technology
Authors: Birol Hansu , Maeder Thomas , Jacq Caroline , Corradini Giancarlo , Boers Marc , Straessler Sigfrid , Ryser Peter
Published: March 2009

The purpose of this paper is to demonstrate sensors and structures fabricated using the
LTCC technology, which has been addressed and employed increasingly as a smart packaging
approach for several applications. The focus will be on inclination and cantilever force sensors and
micro-fluidic structures. Motivation for selection of LTCC for these applications in addition to
fabrication and structuring of the devices will be explained in details. TGA (thermo-gravimetric
analysis), dilatometer analysis, SEM (scanning electron microscopy), electronic equipment for
measuring sensor performance will be extensively used for explanation of the results. It will also be
shown that, compared to classical thick-film technology on alumina, LTCC allows a considerable
increase in sensitivity, and is therefore better suited for the sensing of minute forces and pressures.
The Influence of Li+ on the Sintering of Cordierite Glass Ceramic
Authors: Wang Han Feng , Zhou He Ping
Published: March 2009

The effects of Li+ addition on the sintering and microstructural evolution of cordierite were analyzed. As nucleating agent, the Li+ additive decreased the expansion coefficient and dielectric constant. The doping of Li+ was found to block the phase transition from μ-cordierite to α-cordierite and increase sintering temperatures. The effect of Li+ on the activation of cordierite can be attributed to the nucleation of cordierite. Too much Li+ will inhibit the cordierite crystallization and encourage amblygonite crystallization. Cordierite powders were prepared by sol-gel processing.
Activated Alumina Adsorbent Developed from Waste Aluminum Sludge
Authors: Yu Yan , Ruan Yu Zhong
Published: March 2009

Alumina adsorbent was synthesized from waste aluminum sludge in this research. The nitrogen
isothermal adsorption method (77K) is applied to measure the BET specific surface area and pore
structure of activated alumina at different activation temperatures. The research results indicate that,
thermal treatment has huge influences on the test sample’s specific surface area and pore structure. Its
specific surface area and pore volume expand and then diminish, whereas the holding time rises, getting
its peak of 348 m² /g and 0.55 (cm³ /g) respectively at the activation temperature of 600°C and holding
time for 1 hour. The average pore diameter value increases along with the lengthening of activation
temperature and holding time, reaching the maximum of 11nm at activation temperature of 750°C and
holding time for 4 hours. After comprehensive analysis, the activation temperature of 600°C and holding
time for 1 hour are determined as ideal conditions for activated alumina respectively.
Effects of Heat Treatment Temperature on the Photocatalytic Properties of TiO2 Prepared by Melt-Phase Separation Process
Authors: Zhang Wen Li , Wu Yin Lin , Zhao Ying Na , Zhang Xiao Li , Li Hao Man
Published: March 2009

The principle of melt-phase separation process for preparation of nanoparticle TiO2 is based on
the adjustment of glass phase-separation structure. TiO2 grain size can be controlled by changing heat
treatment temperature. The sample was composed of Na2O-B2O3-SiO2-TiO2 glass system (melted at
1573K). A photocatalytic nanoparticle TiO2 which was loaded on porous glass can be obtained by heat
treatment of glass system at various temperatures and then acid washing. The results have shown that the
glass phase-separation structure size matches crystallization rate and an optimal photodegradation
property of TiO2 is achieved. It was found that the suitable heat treatment condition was at 848K for 12h,
although its performance slightly changes with the composition variations.
Preparation and Property of Self-Dispersed Nanometer γ-AlOOH
Authors: Liao Hai Da , Wu Bo Lin , Zhang Lian Meng , Liao Dong Hua , Wang Hui Xian
Published: March 2009

A peptizing-hydrothermal method to prepare nanometer γ-AlOOH crystal powder with
industrial Al(OH)3 as raw materials has been proposed in the present paper. The XRD and TEM results
show the product is a pure γ type nanometer AlOOH crystal powder with average grain diameter of 70nm.
Laser grading analysis indicates the average grain diameters of the product in the solution are 66.52nm in
water and 84.33nm in N,N-dimethylformamide, respectively without surface modification and dispersant.
The experimental result indicated that polymer/inorganic nano-composite with high content of nanometer
AlOOH presents inorganic characteristic of polymer. The wear rate of the alumina ceramic ball sintered
at 1465°C from ceramic, which contains 98 % alumina (wt), can be reduced up to 40% with addition of
3.5% nanometer AlOOH.
Processing and Properties of Nanocrystalline Tetragonal Zirconia
Authors: Trunec Martin , Maca Karel
Published: March 2009

Zirconia nanopowders (stabilized by 1.5 and 3 mol% Y2O3) with particle size below 10 nm
were compacted by cold isostatic pressing. Pressureless sintering and hot isostatic pressing were applied
to obtain dense nanocrystalline ceramics. The influence of the pore size in powder compacts on sintering
behaviour was investigated. Green bodies pressed at 1000 MPa had a maximum pore size of 5 nm. These
bodies were densified to a relative density of over 99.6% with an average grain size about 85 nm by
pressureless sintering at 1100 °C. Indentation techniques were used to evaluate the hardness and fracture
toughness of zirconia nanoceramics. The decrease in the yttria content from 3 to 1.5 mol% resulted in the
toughness increasing from 5.3 to 11.1 MPa m1/2. The differences in fracture toughness of zirconia
ceramics prepared with different yttria contents and by different sintering methods were discussed and
their possible causes were proposed.
Crack Healing, Reopening and Thermal Expansion Behavior of Al2TiO5 Ceramics at High Temperature
Authors: Kim Ik Jin , Lee Kee Sung , Aneziris Christos G.
Published: March 2009

The low thermal expansion (α25-1100oC = 0.05 ~ 1.6 × 10–6/K) of Al2TiO5 ceramics are apparently due to a combination of grain boundary micro cracking caused by the large thermal expansion anisotropy of the crystal axes of the Al2TiO5 phase. During the reheating run, the individual crystallites expanded at low temperature; thus, the solid volume of the specimen expanded into the micro cracks, where as the macroscopic dimensions remained almost unchanged. As a result, the material expanded very little. The micro cracks closed at higher temperatures. This result is closely related to relatively steeper thermal expansion curves.
Effect of Testing Parameters on Wear Properties of Alumina Strengthen 3Y-TZP Ceramics
Authors: Zhao Shi Hai , Xin Shao Bo , Wang Xiao Hui , Liang Xiao Ping
Published: March 2009

The wear behaviours of alumina strengthen 3Y-TZP ceramics worn against high chromium
cast iron under various testing conditions were investigated using a block-on-block tribometer. The
results showed that the wear rate increases with the increasing of the load and the sliding time. Under the
low load the main mechanism governing the wear properties of ceramic is the apparent plastic
deformation and ploughing, and the wear rate rapidly increases and the wear mechanism changes into
brittle fracture under high load. Meanwhile the wear resistance is depended on the properties of the
abrasive particle. As expected, the wear resistance was increased with decreasing hardness of abrasive
particle, but it was also influenced by the morphology, that is, the sharper the abrasive particle the higher
wear rate.
Finite Element Method for Thermal Analysis and Ablative Calculation of Heat Protection Materials
Authors: Li Zhong Ping , Ding Yuan Fa , Zhang Fan Wei , Zhang Yue
Published: March 2009

Finite element method (FEM) was used for planar ablation problem of heat protection materials based on thermal analysis. ANSYS, a commercial FEM code, was employed for modeling and calculating, and material deleting and boundary moving problems were solved with its advanced techniques. Various heat flux (HF) densities ranging from 1 to 10 MW/m2 as thermal loads were investigated to the effects of heat conduction and ablation, respectively. The results showed that a sudden thermal load can cause great temperature rise and high thermal gradient near the surface of the material. The ablative quantity and ablation rate were also calculated, and mathematical models have been deduced for them.
Grain Characteristics of Nanocrystalline ZrO2 Powders
Authors: Yin Hui Yan , Han Min Fang
Published: March 2009

The grain characteristics of four kinds of ZrO2 nanocrystalline powders were manifested and
discussed in this paper. The grain size of sample 1 tested by XRD, TEM and BET is consistent. The
agglomeration coefficient of Sample 1 is higher, about 62.5, and the span of grain distribution is 14.58.
The grain sizes of Sample 2 and 3 tested by XRD, TEM and BET are different. These differences identify
the crystalline domain including 2~3 unite, which make the departure spheres in TEM. There are more
soft agglomerates in Sample 2 with the agglomeration coefficient of 25.71 and the span of grain
distribution being 18.94 than that in Sample 3 with the agglomeration coefficient of 6.89 and the span of
grain distribution being 8.91. The grain sizes of Sample 4 tested by XRD, TEM and BET are obviously
different. That identifies the large hard agglomerates.
Effect of Ti Content on Microstructure and Dielectric Properties of Li and Ti Co-Doped NiO Thin Films
Authors: Zhang Ya Ru , Zhang Bo Ping , Dong Yan , Li Jing Feng
Published: March 2009

Li and Ti co-doped NiO thin films with 200 nm in thickness were deposited onto Pt/Ti/SiO2/ Si(100) substrates using a sol-gel spin-coating method. The effect of Ti doping content on microstructure and dielectric properties of Li0.10TixNi0.90-xO (x=5-20mol%) thin films was investigated. XRD results showed that all the Li0.10TixNi0.90-xO thin films consisted of a mixture of NiO, Li2NiO2 and NiTiO3 oxides. The intensities of the diffraction peaks for the NiTiO3 phase increased and those for NiO decreased with increasing Ti content, suggesting that a part of NiO phase combined with Ti to form NiTiO3 phase. The dielectric constants of all the Li0.10TixNi0.90-xO thin films at 102 Hz at room temperature ranged from 200 to 400 and increased with increasing Ti content. The frequency stability of the dielectric constant for the Li0.10TixNi0.90-xO thin films was also improved greatly with increasing Ti content.
Preparation and Microwave Dielectric Properties of (1-x)Ca2/5Sm2/5TiO3 -x Li1/2Nd1/2TiO3 Ceramics
Authors: Huang Guo Hua , Xie Qing Lian , Xu Jian Mei , Pan Yin Song , Zhou Dong Xiang
Published: March 2009

(1-x) Ca2/5Sm2/5TiO3-x Li1/2Nd1/2TiO3 (CSLNT) ceramics, suitable for use in resonators or
filters at microwave frequency, have a high εr and a low temperature coefficient of resonant frequency.
The effects of calcinations on the microwave dielectric properties of CSLNT were studied. The CSLNT
(x = 0.3) ceramics sintered at 1300oC for 3 h showed microwave properties with εr of 92, Qf of 5060 GHz
and τf of 7.5 ppm/oC. The microwave dielectric properties of CSLNT (x = 0.3) ceramics were also
improved by soft chemistry methods such as citric acid gel route and ethylenediaminetetraacetic acid
(EDTA) chelating method. The excellent microwave properties with εr = 96, Qf = 6290 GHz and τf = 6
ppm/oC were obtained by EDTA chelating method for CSLNT (x = 0.3) ceramics.
Analysis of Dynamic Response for Piezoelectric Vibration Converter by Finite Element Simulation
Authors: Chu Xiang Cheng , Yan Ren Bo , Gong Wen , Li Long Tu
Published: March 2009

The dynamic behavior of a vibration converter of an ultrasonic motor is described using finite
element method. Tetrahedral finite elements with three dimensions are formulated with the effects of
piezoelectric coupling. And the solution of the coupled electroelastic equations of dynamic motion is
presented. The simulated response of the vibration converter is calculated, and shows excellent
consistency with experimental results, which proved that finite element modeling is a good approach to
optimize piezoelectric apparatus design. A gradual optimized method is employed to ascertain the most
compatible structure.
A Novel Cylinder Driving Ultrasonic Motor
Authors: Li You Guang , Chen Zai Li
Published: March 2009

The paper presents a novel structure cylinder driving USM (ultrasonic motor). Through
development and experimentation, the torque and rotational speed of the prototype were tested, which
proves that this type of USM has a very simple structure, self-adjusting pre-tightening force and
compensation for wear. The results verify the theoretical feasibility and provide instructions for the
industrialization of this type of USM.