bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of Capacitive Microaccelerometers with Squeeze Film Damping and Electrostatic Effects Using Model Order Reduction
Authors: Zhang Ya Fei , Yuan Wei Zheng , Chang Hong Long , Xu Jing Hui
Published: March 2009

Model order reduction is an effective method to generate macromodels for system-level simulation. But it is difficult to deal with the electro-mechanical-damping coupling problems. So we presents a new approach to model the capacitive microaccelerometers with squeeze film damping and electrostatic effects using model order reduction (MOR) method. In this approach, the mechanical, squeeze film damping and electrostatic domains of the devices are modeled separately and then coupled at system-level. The macromodel for squeezed film damping effects could account for slip condition of the flow at low pressure and edge effects. In addition, some important parameters are preserved as symbol. The extracted macromodels are translated into the hardware description language and imported into a circuit simulator. An accelerometer is used to demonstrate the feasibility and efficiency of the proposed approach. Numerical simulation results show that the extracted macromodel can dramatically reduce the computation cost while capturing the device behavior accurately.
Electrical Model of Inside Sense Outside Drive Frame Micro-Gyroscope Including Quadrature Error and Coriolis Offset
Authors: Mo Bing , Liu Xiao Wei , Tan Xiao Yun , Chen Wei Ping , Yin Liang
Published: March 2009

Quadrature error and Coriolis offset are main errors of micro-gyroscopes which caused by manufacturing imperfections. They deteriorate the overall performance of micro-gyroscopes. For inside sense outside drive frame micro-gyroscope, quadrature error and Coriolis offset have their own characters. Based on the mechanical analysis of inside sense outside drive frame micro-gyroscope in imperfect condition, the dynamic equations of condition with quadrature error and Coriolis offset are investigated, and an equivalent electrical model with quadrature error and Coriolis offset is presented. It is convenient to observe the effect of quadrature error and Coriolis offset by equivalent electrical model simulating. Three conditions are simulated and compared. The results indicate that the Coriolis offset reduces the amplitude of instantaneous displacement to a very small extent. Its effect can be neglected. Quadrature error causes an error displacement with the amplitude much bigger than the prefect displacement’s amplitude. It is the overwhelming error in ISOD frame micro-gyroscope.
Advance of the Micro-Magnetometer MEMSMag Research
Authors: Yang Jian Zhong , Pan Li Chao , Kang C.L. , Liu Gang , Li Hui Juan , You Z. , Ren D.H. , Tian Y.C.
Published: March 2009

The MEMS fluxgate magnetic sensor which is characterized by its small mass, smart volume, high sensitivity and outstanding temperature stability, is often applied on the measurements of weak magnetic fields, such as the geomagnetic field. Therefore, it is widely utilized in the field of aeronautics and aerospace field, especially in Nano-/Pico- satellites. MEMSMag, a novel type of micro fluxgate magnetic sensor (MFGM), which exploits magnetic fluxgate principle, was designed and microfabricated, Based on MEMS technology. The micro sensor probe has symmetrical geometry, and is flexible for electrical connection. MEMSMag would be easily assembled into a 3-axis subminiature magnetometer and will be applied to measure vector of the weak geomagnetic field. The microfabrication process was developed. The UV lithography technology in combination with thick negative hard-cured technology was exploited in the microfabrication. The original samples were produced with the dimension of 1 1 100 . The primary tests have been done. The integrity, conductivity and resist test, as well as transformer effect measurement were completed. The statistics, analysis and conclusion of the experimental results have been obtained.
Fabrication and Sensing Properties of PSZT Thin Films for Micro-Force Sensors
Authors: Cui Yan , Chen Hui Lin , Shi Er Lei , Zhao Jia Xin , Wang Li Ding
Published: March 2009

Pb1-xSrx (Zr0.53Ti0.47) O3 (PSZT) thin films have been fabricated on Pt/Ti/SiO2/Si substrate by a sol–gel method combined with a rapid thermal annealing process. The microstructure analysis of the thin films showed that the orientation ratio of (111) was 0.304，0.475 and 0.849 with x=0, 0.03, 0.08. The dielectric measurement suggested that the addition of Sr in Pb(Zr0.53Ti0.47) O3(PZT) thin films greatly improved the dielectric properties of PZT thin films. The dielectric constant for PZT thin films at a frequency of 2 kHz was 648，which was increased to 1239 when 3%at Sr was doped. Meanwhile, the dissipation factor was only increased from 0.02 to 0.03. Three kinds of piezoelectric micro-sensors have been prepared based on PSZT thin films and the sensing sensitivity of 0.017pc/uN, 0.033pc/uN, and 0.011pc/uN were realized as x increased, respectively. It indicated that micro-sensors with PSZT0.03 thin films showed better sensing property than other two.
High Efficient Synthesis of Carbon Nanocoils by Catalysts Produced by a Fe and Sn Containing Solution
Authors: Li Da Wei , Pan Lu Jun , Qian Juan Juan , Ma He
Published: March 2009

Chemical vapor deposition, Catalyst, Carbon nanocoils, High efficient growth
Abstract: Carbon nanocoils (CNCs) were prepared by thermal chemical vapor deposition (CVD) using a Fe and Sn containing solution as the catalyst predecessor. The solutions of Fe2(SO4)3/SnCl2, FeCl3/SnCl2 and Fe(NO3)3/SnCl2 with the mol ratios of 3:0.1 to 3:1 were used as catalysts. Comparing the catalysts in different composition ratios with the grown deposits after CVD, we found that the optimum mol ratio between Fe and Sn is 6:0.1. It is noted that the catalyst combination of Fe2(SO4)3 /SnCl2 obviously increases the quantity of the grown carbon deposits indicating that it has the largest catalytic activity among the three kinds of combinations. Large surface area of catalyst films formed by release of SO3 from the decomposition of Fe2(SO4)3 over the temperature of 480 °C is very good for the carbon nanocoils growth and the introduction of sulfide impurities are the key factors leading to the high efficient growth for carbon nanocoils. It is known that Fe-additions lead to the growth of carbon nanotubes or nanofibers, while Sn induces their helical growth and a little sulfur impurities may induce the efficient growth of carbon nanocoils.
Effect of the Prepared Proceeding on Mechanical and Tribological Properties of DLC Films
Authors: Cheng Guang Gui , Ding Jian Ning , Kan Biao , Fan Zhen
Published: March 2009

In order to analyze the effect of proceeding on the mechanical and tribological properties of DLC films. Three DLC films samples on single silicon wafers were prepared by CVD method. The changed bias voltages were 300V, 350V, 450V separately. The structure and topography of prepared films were studied by Raman spectroscopy and atomic force microscopy (AFM), respectively. The hardness and elastic modulus together with friction coefficient of DLC films were measured by Tribolab system. According to the Raman spectra, the G and D peak shift to left with the increasing of bias voltage. Nano indent showed that the hardness (H) of the DLC films decreases from 19.63GPa to 18.12GPa with the increasing of bias voltages, and the value of elastic modulus (E) is also behaving the same trend as H from 157.95GPa to 146.95GPa. Friction coefficients of the three samples were measured by nano-scratch method under the constant normal load of 1000uN and the slide velocity of 3 um/sec, the corresponding friction coefficient is 0.0804 for DLC300, 0.0508for DLC350 and 0.0594 for DLC450 separately, which indicates that high hardness materials may not necessarily the perfect frictional material, but compound properties of hardness and elastic modulus
Study of Compensatation of the Nonlinear Errors for Thick Film Capacitor Micro-Displacement Sensor
Authors: Ma Yi Wu , Gao Li Sheng , Chang Hui Min , Zhang Zao Chun , Wang Ying Xian
Published: March 2009

This paper discusses the nonlinear errors for a novel gap variation-type thick film capacitive micro-displacement sensor. The micro-displacement sensor is developed for measuring the PZT displacement based on the pattern of PZT deformation-force sensing-displacement. In theory, The capacitor detects the micro-displacement driven by the PZT ceramic，and the variation of capacitance can be transformed into real-time output voltage signals. In this process, there would be some nonlinear errors. Based on the structure and operational principle of the sensor, possible nonlinear errors and their causes are analyzed. Then targeted measures are adopted to deal with them. Results show that the sensor’s linearity can be improved by effective compensating methods.
Study on the Gold-Gold Thermocompression Bonding for Wafer-Level Packaging
Authors: Wu Jing , Jia Shi Xing , Wang Yun Xiang , Zhu Jian
Published: March 2009

The study is performed to implement the Gold-Gold thermocompression bonding for the wafer-level packaging of MEMS chips. Numerous experimental attempts have been carried out to select the metal film adhesive to avoid the Au-Si melt together and optimize bonding processes to intensify the Au-Au eutectic bonding. Finally the results display that the eutectic bonding of the gold-gold are arrived as electrical as well as mechanical interconnection of the MEMS structure and as seal as well as bonding intension.
Electrokinetic Instability Flow in Nanofilm-Coated Microfluidic Channels
Authors: Chen Wei Chih , Hong Ting Fu , Luo Wen Bo , Tai Chang Hsien , Tsai Chien Hsiung , Fu Lung Ming
Published: March 2009

This paper presented a parametric experimental study of electrokinetic instability phenomena in a cross-shaped configuration microfluidic device with varying channel depths and conductivity ratios. The flow instability is observed when applied electric field strength exceeds a certain critical value. The critical electric field strength is examined as a function of the conductivity ratio of two samples liquid, microchannel depth, and the treatment of microchannel wetted surface. It is found that the critical electric field strengths for the onset of electrokinetic instability are strongly dependent on the conductivity ratio of two samples liquid, and decrease as the channel depths increasing of microfluidic devices. In the present study, the surface inside microchannels is treated utilizing hydrophilic and hydrophobic organic-based SOG (spin-on-glass) nanofilms for glass-based microchips. The experimental results indicate that no significant difference for the critical electric fields for the onset of electrokinetic instability phenomena in both hydrophilic and hydrophobic SOG coating in the surface of microchannels. The critical electric fields for the onset of electrokinetic instability phenomena are slightly lower in both SOG coated cases in compare with that of the non-coated microchannel.
A Rapid Analysis Method for Microgyroscope Using System Vibration Modes
Authors: Liu Guang Jun , Wang An Lin , Yu Zi Yi , Yang Xing , Jiang Tao
Published: March 2009

This paper proposes a rapid dynamic analysis method for microgyroscope using system vibration modes to solve the problems concerning to the computing time in the performance analysis of microgyroscope. The results of eigenvalue solution are employed to construct the state space model. The response of the microgyros cope can be reconstructed as a response superposition of the vibration modes, and then the system equation is decoupled into an uncoupled equation. The dynamic response of the microgyroscope can be calculated by a simple superposition.
Simulation of the Optical Properties for Silicon Nano-Pillar Array Using Finite Difference Time Domain Method
Authors: Liao Yuan Xun , Yi Fu Ting
Published: March 2009

We use two-dimensional FDTD (Finite difference time domain) method to simulate light transmitting in Si nano-pillar arrays and get some results. The Si nano-pillar array, with diameters, heights, intervals respectively 50-80nm, less than 480nm, 26-44nm, is used as the testifying structure. The reflectivities of both experiment and simulation match well either for bulk silicon or for structure silicon even though small deviations are caused by the uneven size of the pillar’s diameters, heights, and intervals. What’s more, we find reflectivity (ref) increases along with diameter’s (d) increasing for a single pillar with diameters of 20-100nm under a constant light of 600nm, and reaches 10.48% at d=100nm. And with a constant d equal to 20nm, an infinite aspect ratio (r) and a light 600nm, ref is decreasing when the intervals (i) of pillars are increasing. Finally, under the condition of different i, the relations between ref and r are investigated. The undulation of these curves shows that the reflective waves play an important role in sub-wave length optics. Analysis also reveals that there exists a best i for achieving the lowest ref, too large or too small i will cause high ref, even if r is great; moreover, the lager i is, the higher pillar is needed to achieve the lowest ref.
Carbon Nanofibers Synthesized by Ethanol Catalytic Chemical Vapor Deposition
Authors: Su Yi , Zou Xiao Ping , Cheng Jin , Zhu Guang , Wang Mao Fa
Published: March 2009

. Carbon nanofibers have been attracted many attentions for their potential applications in nanocomposites and electromagnetic wave-absorbing materials due to their remarkable mechanical, electrical and other properties. Ethanol as carbon source possesses low toxicity, easier storage and transportation. In this paper, we report ethanol catalytic chemical vapor deposition (ECCVD) for synthesizing carbon nanofibers. We utilized ferrocene as catalyst precursor and use ethanol as carbon source to synthesize carbon nanofibers by ethanol chemical vapor deposition. The deposits were characterized by employed scanning electron microscopy, transmission electron microscope and Raman spectroscopy.
Analyzing the Response of Spring-Mass-Capacitor Structure Using Energy Method
Authors: Zhou Wu , He Xiao Ping , Su Wei , Li Bai Lin
Published: March 2009

The spring-mass-capacitor structure in micro-electro-mechanical systems (MEMS) is a typical macromodel, its response and stability under step voltage is presented in this paper. Energy method is used to analyze the dynamic behavior of mass block where its velocity is zero and accelerometer is zero, respectively. The condition of stability under step voltage is the initial stiffness ratio must less than 0.25, and finally the relation of energy loss and oscillating behavior of block is analyzed. The conclusion is useful to analyze the response of structure and helpful to design a MEMS system composing of spring-mass-capacitor structure.
Flexible Microelectrode Array on Parylene for Subretinal Stimulation and its Biocompatibility Test
Authors: Huang Xian Ju , Yu Wei Hong , Wang Wei , Zhao Chan , Gao Cheng Chen , Wang Xu Qian , Yang Zhi Kun , Li Zhi Hong , Dong Fang Tian
Published: March 2009

Parylene C, an emerging material in microelectromechanical systems (MEMS), is now widely applied to neural prosthesis devices, such as artificial retinal implants, due to its well-known biocompatibility and ability to be easily patterned by oxygen plasma etching. This work presents a flexible parylene-based microelectrode array（MEA）using MEMS techniques aiming for the chronic subretinal stimulation. The MEA was successfully manufactured and inserted into the subretinal space of a rabbit eye by a novel surgical operation. Optical Coherence Tomography(OCT) showed that a chronic implantation of parylene-based electrode arrays in the rabbit retina over a three month follow-up period demonstrated that the present chip system has a good biocompatibility with the subretinal organs without obvious damages.
A DC Voltage Driven Flow-Through Electroporation Microchip
Authors: Zhao Qiao Le , Lin Yu Cheng , Huang Qin Gan
Published: March 2009

Differing with the traditional way to perform electroporation (EP) by using the DC electrical pulse, this paper proposes a new EP system by applying continuous DC voltages to generate proper EP electric field strengths utilizing the shape change of the channel. The fabrication of chip and set-up of system are clearly described and simulations also carried out utilizing CFD-ACE to study the electric field strength distribution and the time span when fluid passes through different electric field strengths. The fabrication of the proposed EP system is quite simple and low-cost.
Modeling and Simulation of Opposite Type MATA Using MEMS Nodal Cell Library
Authors: Lu Dong Xun , Li Wei Hua
Published: March 2009

In MEMS nodal analysis method, more available libraries of nodal models are needed. By analyzing the mathematic model and the equivalent model of the electro-thermal-mechanical beam, this paper shows the steps of building a library of a nodal element for HSPICE. Then the cell library is used to simulate the opposite type micro-array thermal actuator (MATA). At last it shows the DC sweep performance and the transient performance of opposite type MATA. In this paper, to verify the reusability of the beam cell, opposite type MATA is all consisted of the electro-thermal-mechanical beam cell in library.
Simulation of Nanofibers Movement for Near-Field Electrospinning
Authors: Wang Hong Lian , Zheng Gao Feng , Sun Dao Heng
Published: March 2009

NFES is a new and simple way to realize precision-positioning of nanofiber. A model on NFES nanofiber movement is built to analyze the effects of the existed nanofibers which have been collected on the substrate, on the nanofiber’s dropping movement. During electrospinning nanofiber is affected by the electric field force, Coulomb repulsive force, air resistance force gravity and so on. The influence of parameters on the deposition behavior of as-spun nanofiber is discussed. The simulation results show that (i) with charge density increasing, the final spacing between mass center of nanofibers A and B (FSAB) increases and the movement distance of center-of-mass of nanofiber B (MDB) decreases first and then increases; (ii) FSAB increases with applied voltage, but decreased in narrow range with concentration of PEO increasing; (iii) FSAB decreased with the initial spacing between mass center of nanofibers A and B (ISAB) increasing, and then it increases after reaching the minimum. So does ISAB to DMB. This simulation model would improve the controlling of nanofiber in NFES.
Detection for Spring Constant of Microcantilevers in Atomic Force Microscopy Based on Frequency Measurements
Authors: Wang Fei , Zhao Xue Zeng
Published: March 2009

Micro cantilevers in atomic force microscopy are important force sensors in nano research, and the spring constant is one of the most important parameters of the cantilevers. Normal testing methods are not suitable for the spring constant detecting of micro cantilevers according to the strict scale of the cantilevers, and new methods are needed to the study of micro cantilevers. A method for detecting of spring constant of micro cantilevers based on combining the numerical simulation and frequency measurements is presented in this paper. The new method involves four steps, the first step is developing the vibration model of the micro cantilever studied immersed in air and determine the fluid parameters in the model during dynamic tests in atomic force microscopy presented in this paper; the second step is analyzing the vibration behavior of the corresponding cantilevers with the same geometry but different young’s modulus. The third step is measuring the natural frequencies of the micro cantilevers and comparing the experimental results with the numerical results to determine the young’s modulus of the cantilever. The last step is conducting the young’s modulus to the cantilever FEA model for determination of its spring constant. Experiments on a NSC cantilever have been done to validate the method presented in this paper.
Photochemical Synthesis of Gold Nanostructures in Different Solvents
Authors: Guo Bin , Tang Yong Jian , Li Xi Bo , Wu Wei Dong , Luo Jiang Shan , Cheng Jian Ping
Published: March 2009

Gold nanostructures were synthesized at room temperature under irradiation of a fluorescent lamp in mixture of gold seeds smaller than 10 nm, HAuCl4, and poly(vinylpyrrolidone) (PVP). N,N'-dimethylformamide (DMF), water or ethylene glycol (EG) was used as solvent respectively. The products were characterized by transmission electron microscopy, X-ray diffraction and absorption spectra, and the results indicated that under light irradiation at ambient, the reducibility of the three solvents for HAuCl4 ranked as: EG> water> DMF, all far weaker than that of PVP; PVP also prevented the nanostructures from precipitating; gold seeds seemed to impose an autocatalytic effect to facilitate the reduction of HAuCl4; light irradiation was essential for high-yield production of gold particles; the above factors influenced the morphology and size of the gold structures, and led to formation of particles within nano or micron scale in shape of spheroid, rod or plate.
Uniaxial Stress Dependence of Electrical Properties of Ulrathin Ballistic P-Type Silicon Nanotransistor
Authors: Zhang J.H. , Huang Qing An , Yu H. , Wang J.
Published: March 2009

. In this paper, in order to determine whether the ballistic current enhancement saturates at very high stress level or can be further improved, the effect of uniaxial stress on the ballistic transport of the double-gated, ultrathin-body p-type silicon nanotransistor is investigated using a self-consistent device simulator, which combines the stress-dependent six-band k.p model and a semiclassical top-of-the-barrier ballistic transport model. Based on a semi-continuum atomistic lattice model, the size-dependent elastic constant correction has been for the first time coupled into this simulator. Our results presented here indicate uniaxial compressive stress at moderate levels improves ballistic performance by about 85% while uniaxial tensile stress slightly reduces ballistic drive current. Interestingly, higher compressively strained channel does not offer higher drive current. Although significant variations in the size-dependent elastic constants are found, the ballistic current shows only a small decrease after considering the elastic constant correction. Furthermore, the competition of injection velocity and carrier density related to hole effective masses is found to play a critical role in determining the performance of the nanotransistors.
MEMS Dielectrophoresis Device for Osteoblast Cell Stimulation
Authors: Zou H. , Syms R.R.A. , Mellon S. , Tanner K.E.
Published: March 2009

A fixed microelectrode device for cell stimulation has been designed and fabricated using micro-electromechanical systems (MEMS) technology. Dielectrophoretic forces obtained from non-uniform electric fields were used for manipulating and positioning osteoblasts. The experiments show that the osteoblasts experience positive dielectrophoresis (p-DEP) when suspended in iso-osmotic culture medium and exposed to AC fields at 5 MHz frequency. This work will help to investigate the mechanisms underlying Wolff’s law of bone growth dynamics at the cellular level. The methods used can also be developed to control osteoblast metabolism and ultimately enhance bone repair processes.
Effects of Packaging on RF MEMS Switch’s Return Loss
Authors: Yang Le , Liao Xiao Ping
Published: March 2009

Packaging of MEMS has been identified as one of the most significant areas of research for enabling MEMS usage in product applications. In order to make MEMS a real-life opportunity, it is vital to explore and develop an understanding of the possibilities and limitations of MEMS packaging. This paper presents several packaging structures for RF MEMS switch which based on GaAs substrate. The return loss of X-band RF MEMS switch before and after packaged can be simulated by Ansoft HFSS. The results show that return loss of RF MEMS switch after packaging deteriorated at least 3dB compared with that of before. Thermal mismatch caused by the variation of the temperature in the packaging process will introduce additional thermo-elastic strain and geometric deformation into the mechanical structure. The influence on return loss of the RF MEMS switch is researched in this paper too. Considering that, return loss simulated by HFSS decreases from -16.38dB to -16.88dB. Then, some design guidelines of RF MEMS packaging derived from the simulation of HFSS are also concluded at the end of the article.
Kinetic Monte Carlo Simulation for the Evolution of Complex Surface in Fabrication of MEMS Devices
Authors: Xing Yan , Qiu Xiao Li
Published: March 2009

This paper introduces a octree search Kinetic Monte Carlo(OS-KMC) that combines the topological requirements for representing an evolving multivalued surface using minimal memory and an efficient search algorithm for the realization of the KMC time evolution. In addition, the data structure for OS-KMC also provides a nature way to generate hexahedral element meshes for the integration between simulator and performance analysis tool. The density of mesh grid and the refinement of the hexahedral element can be controlled in this octree based mesh generation method. In simulating surface morphology during wet etching and micro structure formed by composite MEMS processes, the octree search KMC shows good simulation results with better calculation performance. The octree structure enables the Monte Carlo solutions for large scale problems with complex dynamic surfaces.
Multi-Scale and Finite Element Analysis of the Mixed Boundary Value Problem in a Perforated Domain under Coupled Thermoelasticity
Authors: Feng Yongping , Cui Junzhi
Published: March 2009

The two-scale asymptotic expression and error estimations based on two-scale analysis (TSA) are presented for the solution of the increment of temperature and the displacement of a composite structure with small periodic configurations under coupled thermoelasticity condition in a perforated domain. The two-scale coupled relation between the increment of temperature and displacement is established.The multi-scale finite element algorithms corresponding to TSA are described and numerical results are presented.
Mechanics Framework for Micron-Scale Planar Structures
Authors: Chong A.C.M. , Yang Fan , Lam David C.C. , Tong Pin
Published: March 2009

Structures are assemblies of planar and three-dimensional objects. Planar components and parts are commonly because the deformation behaviors of plates and beams can be analyzed within the plane problem framework. For micron-scale structures, patterning processes in microfabrications are intrinsically planar and the resulting fabricated structures are also planar. These planar micron-scale structures have been designed and analyzed using conventional mechanics, but increasingly as the sizes of these structures become smaller, higher order effects become significant. In nanometer-scale, surfaces were recognized to play significant roles in affecting the physical behavior. Size dependent elastic and plastic deformation behaviors in micron-scale structures were also observed. Size dependence is an intrinsic part of higher order theory of mechanics and has been used successfully to explain scale dependent behavior in threedimensional structures. In this paper, two-dimensional higher order elastic relations in plane stress and plane strain for compressible solids are developed. The difference between the higher order and conventional elasticity theories is compared
Thermal Shock and Thermal Fatigue of Ferroelectric Thin Film due to Pulsed Laser Heating
Authors: Zheng X.J. , Deng S.F. , Zhou Yi Chun , Noda Naotake
Published: March 2009

Thermal shock and thermal fatigue of ferroelectric (FE) thin films were investigated by the pulsed laser tests. The power density was gradually increasing in the single pulsed laser heating test which simulated a thermal shock, the part melting threshold of Pb(Zr0.52Ti0.48)O3 (PZT) thin films was found by scanning electron microscopy (SEM). After thermal shock resulted the highest temperature below Curie point at the surface of PZT thin film, X-ray diffraction (XRD), SEM and RT66A standard ferroelectrics analyzer were used to study the microstructure, crystal grain sizes, and ferroelectric failure behavior. It was found that XRD peak of PZT thin film after laser beam heating was stronger than that before laser beam heating, crystal grain sizes decreased, and the ferroelectric properties were degraded. However there was no crack observed by SEM, until PZT thin films were melted. The fined grain effects on ferroelectric properties and XRD patterns of PZT thin film, depolarization due to the single pulsed laser heating were discussed respectively. The pulsed cycles with a certain power density were gradually increasing in the repetition pulsed laser heating test. It was interesting to find that the cracks will initiate and propagate due to the thermal fatigue induced by the repetition pulsed laser. The possible origins of the thermal fatigue cracks were also discussed.
Size Effect in Fracture Toughness Determination of Brittle Materials
Authors: Chlup Zdeněk , Dlouhý Ivo
Published: March 2009

Each material has some limiting factors for its massive use in structural applications. It
holds in the case of brittle materials all the more. The main limiting factor for ceramic based
materials is the brittleness and its natural scatter. It is necessary to have reliable fracture toughness
characteristics when ceramic based material tends to be used in industrial scale. There is a few
methods used for fracture toughness determination; straight notch and chevron notch technique are
the most frequently used. Both methods have advantages (i.e. straight forward evaluation in the case
of straight notch and easy preparation in the chevron notch technique) and disadvantages (i.e. slow
preparation stage in the straight notch and complicated evaluation in case of the chevron notch).
There is an increasing need to test geometrically non standard (i.e. sub-sized) test pieces. This paper
is focused on the statistical aspect of size effect at fracture toughness evaluation having used both
techniques. Sets of test pieces tested at various geometrical conditions were used for this study. The
obtained fracture toughness data were statistically evaluated with the aim to describe and explain
the influence of the geometrical parameters on the fracture toughness and scatter of measured data.
Fractographical analyses of fracture surfaces were used to identify possible sources of the scatter
and to validate the tests.
Experimental Study on SHS under High Nitrogen Pressure
Authors: Grachev V.V. , Borovinskaya I.P.
Published: March 2009

Gas-solid systems are among a large class of systems in which self-propagating hightemperature
synthesis (SHS) is observed. Powders of metals and non-metals burn in the atmosphere
of gaseous reagent and the products of the reaction are solid. A variety of nitrides and different
composites were synthesized by combustion of porous powder compacts in nitrogen atmosphere.
The conversion, achieved during the combustion process, as well as the composition and structure
of the products, significantly depends on the nitrogen pressure. Most of the published experimental
results on this topic were obtained under nitrogen pressure of less 10 MPa and only few systems
were investigated under higher pressures. In this work we present the results of the studies on the
combustion process in the range of high nitrogen pressures of 40-400 MPa for two systems, such as
Nb-N2 and B-C-N2. Dependences of combustion characteristics, phase composition and
microstructure of the synthesized products on the nitrogen pressure were studied.
SHS Synthesis of the Materials in the Ti-Al-C-N System Using Intermetallics
Authors: Chlubny Leszek , Lis Jerzy , Bućko Mirosław M.
Published: March 2009

Materials in the Ti-Al-C-N system due to their specific heterodesmic structure show
pseudo-plastic properties. Direct synthesis of these compounds from respective elements requires
high-temperature and long-lasting reaction. Presented work shows attempts to prepare some ternary
compounds using self-propagating high-temperature synthesis (SHS). Intermetalic precursors, TiAl
and Ti3Al, were used to synthesize fine and sinterable powders of 211 and 312 complex structure
materials.
(SiC/Ti3SiC2)n Multi-Layered Coatings Deposited by CVD
Authors: Jacques Sylvain , Fakih Houssam
Published: March 2009

Thin (SiC/Ti3SiC2)n multi-layered coatings were deposited at 1100°C on ceramic
substrates by chemical vapour deposition (CVD) methods. Each SiC sub-layer was classically
processed from H2/CH3SiCl3. Each Ti3SiC2 sub-layer was obtained by reactive CVD (RCVD) from
a H2/TiCl4 gaseous mixture reacting on each SiC solid sub-layer that was previously deposited. The
growth of Ti3SiC2 by RCVD involves partial or total SiC consumption. The H2/TiCl4 ratio was
chosen on the basis of a thermodynamic study. Using a sufficiently high H2/TiCl4 ratio and limiting
the sub-layer thickness allowed the formation of TiC or binary titanium silicides to be avoided. By
using a constant low gas pressure in the CVD reactor, it was possible to obtain nearly pure Ti3SiC2
sub-layers as thin as 0.8 μm. In that case, the ternary compound exhibits basal planes oriented
perpendicular to the substrate surface. A way to obtain thinner sub-layers was the use of a pressurepulsed
CVD method. In addition, the pressure-pulsed method allowed the preferential orientation to be
prevented in the Ti3SiC2 coating.
Influence of the Architecture on the Mechanical Performances of Alumina-Zirconia-Mullite Ceramic Laminates
Authors: Costabile Alessandra , Sglavo Vincenzo M.
Published: March 2009

Ceramic laminates with different architecture have been produced and characterized in
this work. Thickness of single layers, composition and stacking sequence have been changed in
order to modify the corresponding stable growth range of surface defects and final strength.
Laminates composed of alumina/zirconia and alumina/mullite have been considered. The
mechanical behaviour of the materials is discussed in terms of the residual stress profile and the
apparent fracture toughness curve.
Functionally Graded Electrode Materials for Thermoelectric Devices
Authors: Li Jing Feng , Zhang Huai Quan
Published: March 2009

The electrodes for solar thermoelectric modules require high thermal conductivity in the
thickness direction and high electrical conductivity in the plane direction; but the whole electrode
must be electrically insulated in the thickness direction. To meet such requirements, two material
systems of TiB2/AlN/Cu and Cu/AlN/Cu with AlN as a middle layer were designed and studied,
because AlN has high thermal conductivity and electrical resistance. The TiB2/AlN/Cu FGMs were
fabricated via spark plasma sintering (SPS) method, in which a temperature gradient was achieved
by using a specially designed mold. The Cu/AlN/Cu symmetrical FGMs were fabricated by an
infiltration-like process using a symmetrical porosity-graded AlN plate as a preform.
Development of Multi-Layered and Graded Die Coatings for Materials Processing Applications
Authors: Lin Ji , Kunrath A.O. , Zhong D. , Myers S. , Mishra Brajendra , Moore John J.
Published: March 2009

The paper will present the methodology used to design optimized die coatings employed in
material forming processes in an effort to extend the life and effect efficient operation of the dies. An
optimized die coating 'architecture' requires that the coating system be essentially non-wetting with
the material (metal, glass, polymer) being formed in the die, coupled with good wear and oxidation
resistance Other factors, such as delaying the onset of thermal fatigue cracking (heat checking), and
an acceptably low coefficient of friction. And, possibly, self-lubricating, also need to be considered
based on the processing and forming conditions that include both liquid and solid materials. Many
different die coatings have and are being used with different levels of success. This paper presents the
current understanding that has been gained in laboratory testing, in-plant trials, and modeling in an
effort to generate a fundamental understanding of how such optimized die coating systems may be
designed for specific forming operations and conditions, with examples based on dies used in
aluminum pressure die casting, glass molding, and metal forming operations.
Development and Application of Coated Ceramic Cutting Tools
Authors: Uhlmann E. , Hühns T. , Richarz S. , Reimers Walter , Grigoriev S.
Published: March 2009

Ceramics are characterized by their special wear and temperature resistance. Thus, they are
especially suited for the cutting of high-temperature alloys and difficult-to-cut materials. Due to their
low ductility, they show brittle-hard properties during the process, which lead to a sudden failure of
the tool. But it is possible to create composite materials that counteract the brittle-hard behavior of the
substrate material by PVD-coating. The objective of the investigations is to increase the process
stability of coated ceramic indexable inserts made of aluminum oxide and silicon nitride through the
optimisation of the mechanical pre-treatment of the substrate materials. To this end, the ceramic
substrates are pre-treated by different abrasive machining processes. Comprehensive measurement
evaluations show the influence of the machining process and strategy on the formation of surface and
subsurface. The workpieces ground and lapped in different ways are subsequently coated by an
especially developed PVD process. Measurements show the influence of the pre-treatment on the
surface structure and on the mechanical properties of the composite material. The application of the
developed and manufactured tools in cutting tests verifies the results of the measurements.
Low Temperature MOCVD-Processed Alumina Coatings
Authors: Gleizes Alain , Şovar Maria Magdalena , Samelor Diane , Vahlas C.
Published: March 2009

We first present a Review about the preparation of alumina as thin films by the technique
of MOCVD at low temperature (550°C and below). Then we present our results about thin films
prepared by the low pressure MOCVD technique, using aluminium tri-isopropoxide as a source,
and characterized by elemental analysis (EMPA, EDS, ERDA, RBS), FTIR, XRD and TGA. The
films were grown in a horizontal, hot-wall reactor, with N2 as a carrier gas either pure or added with
water vapour. The deposition temperature was varied in the range 350-550°C. The films are
amorphous. Those prepared at 350°C without water added in the gas phase have a formula close to
AlOOH. Those deposited above 415°C are made of pure alumina Al2O3. When water is added in
the gas phase, the films are pure alumina whatever the deposition temperature.
MOCVD Route to the Fabrication of Calcium Copper Titanate (CaCu3Ti4O12) Thin Films
Authors: Lo Nigro Raffaella , Toro Roberta G. , Malandrino Graziella , Fragalà Ignazio L.
Published: March 2009

CaCu3Ti4O12 (CCTO) thin films have been successfully deposited by Metal Organic
Chemical Vapor Deposition (MOCVD) technique. A novel approach based on a molten multicomponent
precursor source has been applied. The molten mixture consists of the
Ca(hfa)2•tetraglyme, Ti(tmhd)2(O-iPr)2, and Cu(tmhd)2 [Hhfa= 1,1,1,5,5,5-hexafluoro-2,4-
pentanedione; tetraglyme= 2,5,8,11,14-pentaoxapentadecane; Htmhd= 2,2,6,6-tetramethyl-3,5-
heptandione; O-iPr= iso-propoxide] precursors. Film complete structural and morphological
characterizations have been carried out using several techniques [X-ray diffraction (XRD), scanning
electron microscopy (SEM), transmission electron microscopy (TEM)].
Morphological and Structural Characterization of TiN/ZrN Superlattices Deposited by Reactive R.F. Magnetron Sputtering
Authors: Rizzo Antonella , Signore Maria A. , Di Luccio Tiziana , Tagliente M. Antonella , De Riccardis Maria Federica
Published: March 2009

TiN/ZrN multilayers coatings have been deposited using a reactive R. F. magnetron
sputtering process. Nitride layers with different sputtering conditions have been stacked in order to
obtain superlattices having different preferred orientations. The deposition rate has been
considered as independent parameter which changes the energy and the momentum transfer of the
backscattered particles, influencing films structure evolution.
Structure and Electromechanical Properties of Quenched PMN-PT Single Crystal Thin Films
Authors: Wasa Kiyotaka , Kanno Isaku , Suzuki Takaaki
Published: March 2009

Thin films of single c-domain/single crystal (1-x)Pb(Mg1/3Nb2/3)O3－xPbTiO3 (PMN-PT), x≅0.33
near a morphotropic boundary (MPB) composition, were heteroepitaxially grown on
(110)SRO/(001)Pt/(001)MgO substrates by magnetron sputtering. The heteroepitaxial growth was
achieved by rf-magneron sputtering at the substrate temperature of 600oC. After sputtering
deposition, the sputtered films were quenched from 600oC to room temperature in atmospheric air.
The quenching enhanced the heteroepitaxial growth of the stress reduced single c-domain/single
crystal PMN-PT thin films. Their electromechanical coupling factor kt measured by a resonance
spectrum method was 45% at resonant frequency of 1.3GHz with phase velocity of 5500 to 6000m/s
for the film thickness of 2.3μm. The d33 and d31 were 194pC/N and –104pC/N, respectively. The
observed kt , d33 ,and d31were almost the same to the bulk single crystal values.
Development of Monolayered Low Friction PVD Ceramic Coatings for Application on Tools and Mechanical Components
Authors: Wiklund Urban , Stavlid Nils , Hogmark Sture
Published: March 2009

Ceramic carbon based coatings have become common on tools and machine components,
mainly because they offer a greatly reduced friction, as compared to uncoated steel contacts, in
combination with a considerable wear protection. Very often they contain alloying elements such as
different metals to control properties like hardness, wear resistance and lubricity. Applied to
component surfaces, also properties relating to the running-in behaviour become important since an
efficient running-in is crucial for their long term steady-state functionality. Also, even though
component coatings are meant to provide low friction in dry sliding, they are increasingly used also
in lubricated situations. This raises demands for compatibility with common lubricants. All these
aspects have to be considered when developing new tribological coatings and some of these are
addressed in this work. Results from different sliding tests with coated and uncoated surfaces in
both dry and boundary lubricated contacts are presented. The generated tribofilms and their
influence on the tribological properties are compared for the different sliding conditions. It is also
shown how lubricants and their additives can affect the running-in, the tribofilm formation, and
alter the steady state friction.
Microstructural and Mechanical Characterization of Mechanically-Activated Plasma-Sprayed Nanostructured Al2O3-TiO2 and Al2O3-ZrO2 Coatings
Authors: Coste Sandrine , Bertrand Ghislaine , Coddet Christian , Gaffet Eric , Hahn Horst , Sieger H. , Meunier Cathy , Vives Serge
Published: March 2009

Granulated nanostructured alumina/titania and alumina/zirconia powders were used to achieve
coatings by atmospheric plasma spraying. Raw materials and mechanically activated ceramic
mixtures (alumina with 13wt% and 44wt% of titania or 40wt% and 80wt% of zirconia) have been
considered to produce the sprayable powders. Effects of various plasma spray conditions (primary
Ar and secondary H2 gas flow rates, arc intensity) on the microstructure, phase content and
microhardness of the coatings have been evaluated. It has been shown by SEM observations that the
coatings exhibit a lamellar structure consisting in fully melted and partially melted areas including
porosity, ranging from 10 to 30vol.%. The phase changes (from αAl2O3 to γAl2O3, from anatase to
rutile for TiO2, Al2TiO5) or structural changes that occur during the plasma spraying of the
nanostructured powders were investigated by XRD and related to the processing conditions and in
turn to the amount of unmelted powder.
Coating of Polymer Surfaces by Liquid Phase Deposition of TiO2: A Biologically-Inspired Approach
Authors: Löbmann Peer
Published: March 2009

The coating of polymer surfaces with ceramics up to now is basically only accomplishable
by vacuum-based technologies such as sputtering, because the thermal load is low compared to
other methods such as sol-gel processing. Since the investment costs for the equipment required are
considerably high and the coating is limited to line-of sight deposition, simple and cost-effective
processing routes are sought.
In all higher organisms inorganic materials are synthesized at ambient temperatures under physiological
conditions. Therefore the study of biomineralization processes has gained considerable academic
attention in the last decades. One of the key features of inorganic material deposition in vito
is the interaction between supersaturated solutions and specifically modified surfaces.
Following this paradigm so-called bio-inspired approaches can be developed which go beyond the
current limitations of synthetic techniques. One example is the mineralization of planar polymer
surfaces with TiO2 at 50oC. Using polystyrene latex particles as templates, all four stages
commonly found in natural biomineralization can be emulated in a completely artificial system.
Nanostructured Ceramic Thin Films and Membranes by Wet Chemical Processing Methods
Authors: Shi Jing Yu , Mottern Matthew L. , Shqau Krenar , Verweij Henk
Published: March 2009

Nanostructured ceramic thin films and membranes are used for protective or functional
purposes and prepared on dense or porous substrate materials. Wet chemical methods enable
cheap, low-temperature, mass-scale manufacturing routes. They produce fine-grained porous and
dense micro-structures that cannot be realized otherwise. In wet-chemical processing, clean
nanoparticle dispersions are deposited on the substrate at, primarily, ambient conditions. The
deposition is followed by a (rapid) thermal processing treatment to remove liquids and organic
additives, to convert precursors to the target composition, and to establish the final porous and
dense micro-structure. In the synthesis of precursor dispersions it is very important to obtain
nanoparticles with a near-isometric shape and a fairly narrow particle size distribution, without the
formation of secondary (agglomerate) structures. In particular the latter requires careful control of
solution and interfacial chemistry to achieve proper colloidal stability, during and after the
synthesis process. Characterization of coating integrity, defect morphology and defect population
is done by decoration methods, microscopy, ellipsometry and statistical methods that employ
membrane transport properties.
The Influence of PZT Film Thickness on Microstructure in CSD Processing
Authors: Etin A. , Shter G.E. , Grader G.S.
Published: March 2009

The R&D of state of the art PZT (PbZrxTi1-xO3) films is important due to their
piezoelectric, pyroelectric and ferroelectric properties. Currently, Chemical Solution Deposition
(CSD) methods (e.g. spin coating of a sol-gel precursor solution) are successfully used in our lab to
deposit PZT films with intermediate thickness. This method employs multiple coating procedures
and different microstructure is observed after each coating. We report on the film microstructure
evolution studied by quantitative analysis of HRSEM images as a function of thickness.