bluuebunny/crossref_metadata_2025 huggingface dataset:
Water Versus Acetone Electrophoretic Deposition of Hydroxyapatite on 316L Stainless Steel
Authors: García-Ruiz Georgina , Vargas Gregorio , Méndez-Nonell J. , Uribe S. A.
Published: March 2009

Hydroxyapatite (HAP) was electrophoretically deposited on 316L stainless steel in order to promote a bioactive surface. The effect of dispersing media (water and acetone), applied voltage and the deposition time on the deposit weight and microstructure of the coatings was evaluated. The deposition time was varied in the range of 1 to 900 s for water suspensions and 0.5 to 180 s for acetone suspensions. Suspensions were prepared by using HAP powder with an average particle size of 1.5 μm at a concentration of 1 % by weight. The deposition was performed under a direct current (DC) field of 400 to 1000 V for acetone suspensions and 5 to 50 V for water suspensions. The coatings were analyzed using scanning electron microscopy. The amount of hydroxyapatite on the surface of the metallic substrate was evaluated by determining the difference in weight of the samples, before and after the electrophoretic process. The stabilization of HAP particles in water was achieved using 1 % by weight of Dispex N40TM and 0.001M KCl. Under this condition the zeta potential of HAP in water suspension was –28 mV. Non additive was required in acetone suspensions. Dense, homogeneous and crack-free coatings of sub-micron particles (0.63 mg/cm2) were obtained by applying 5 V during 60 s in water suspensions. Above a DC field of 5 V the hydrolysis of water seriously difficulties the coatings formation. Homogeneous and crack-free coatings of sub-micron particles (1.45 mg/cm2) were also obtained in acetone suspensions applying 400 to 1000 V during 5 s. Lower voltages were not used with acetone suspensions due to its high resistivity.
Electrophoretic Deposition of Different Yttria-Stabilized Zirconia Powder on Stainless Steel and Carbon Electrodes
Authors: Hayashi Shigeo , Nakagawa Zenbe-e
Published: March 2009

Stabilized zirconia is a common material for oxygen sensors as a solid electrolyte. The electrophoretic deposition (EPD) behavior of 8Y-YSZ (Yttria-stabilized zirconia with 8 mol% Y2O3) powder was investigated on stainless steel and carbon based substrates. This study will be the starting point for the fabrication of complex shaped (even in micro-scale) YSZ based devices. Ethanol + HNO3 based suspensions were used for the EPD experiments and three different YSZ powders were deposited, one commercially available powder and two own-made coprecipitated powder. The latter powders were calcined at respectively 900 and 1200°C. The concentration of the suspension was 3 g/300 cm3, and a small amount of HNO3 solution was added as a dispersant. DC electric field of 100-200 V/15 mm was applied between parallel electrodes. It was found that on stainless steel electrodes the calcined own-made coprecipitated powder showed the best best deposition properties, whereas the commercial YSZ powder showed the best deposition properties on carbon electrodes. These experimental results are discussed with regard to some powder properties (e.g. particle size distribution and packing behavior) and the adhesion between the particles and the substrate.
Study on the Multi-Scale Nanocomposite Ceramic Tool Material
Authors: Liu Han Lian , Huang Chuan Zhen , Wang Jun , Liu Bing Qiang
Published: March 2009

An advanced ceramic cutting tool material was developed by means of micro-scale SiC particle cooperating with nano-scale SiC particle dispersion. With the optimal dispersing and fabricating technology, this multi-scale nanocomposite may get both higher flexural strength and fracture toughness than that of the single-scale composite. The improved mechanical properties may be mainly attributed to the inter/intragranular microstructure with a lot of micro-scale SiC particles located on the grain boundary and a few nano-scale SiC particles located in the matrix grain. Because of the thermal expansion mismatch between SiC and Al2O3 resulting in the compressive stress on the SiC/Al2O3 interface, the interface bonding strength between Al2O3 and SiC was reinforced, which can compel the crack propagating into the relatively weak matrix when meeting the SiC particle on the boundary; while the alumina grain boundary is not the same strong as the SiC/Al2O3 interface and the Al2O3 grain, therefore the crack propagates sometimes along the Al2O3 grain boundaries and sometimes through the grains, when reaching to the nano-scale SiC particle inside the matrix, the crack was pinned and then deflected to the sub-grainboundaries. These coexisting transgranular and intergranular fracture mode induced by micro-scale and nano-scale SiC and the fining of matrix grain derived from the nano-scale SiC resulted in the remarkable strengthening and toughening effect.
Forces in Surface Grinding of Granites with a Brazed Diamond Wheel
Authors: Huang Hui , Zhang G.Q. , Zhan Y.J. , Xu Xi Peng
Published: March 2009

An experimental study was carried out to investigate the process in surface grinding of two
kinds of typical granite with a brazed diamond wheel. The horizontal and vertical forces were
measured to obtain the data for the tangential and vertical force components as well as specific energy.
Micrograph observations on tool surface and granite surface were coupled to check the prevailing
mechanisms for material removal. Although the red granite is more difficult to machine than the black
granite, according to factory records, the normal and tangential force components and specific energy
for red granite were lower than that for black one, which might be attributed to the high height
protrusion of brazed tool and the more ductile flow occurred in the grinding arc of black granite
compared to the red one.
Deposition of Diamond Films on Smooth Surfaces of Cemented Carbide Inserts with Cobalt Boride Interlayers
Authors: Wang Y. , Ma Y.P. , Sun Fang Hong , Zhang Zhi Ming , Chen Ming
Published: March 2009

Improving adhesion and surface roughness of diamond films on WC–Co substrate is the
key factor of the widespread application of diamond coated tools. A new pretreatment method has
been performed for smooth Co-cemented carbide inserts in order to lower the surface roughness of
diamond films under the premise of good adhesion between diamond films and substrates. The
effect of the new pretreatment on the adhesion of the diamond films is investigated. Research
results show that the boronization pretreatment can effectively suppress cobalt diffusion to the
surface and avoid catalytic effect of Co at high temperature. This new pretreatment can avoid the
surface roughening of inserts and ensure the deposition of smooth diamond films. Investigation
shows that the optimum boronization compounding is a powder mixture of
70%B4C+15.5%KBF4+1.5% La2O3+13%Na2CO3. Adhesion between substrates and diamond films
is evaluated by Rockwell A indentation tests and the cutting performance of the diamond-coated
tools is investigated by the cutting tests. Diamond films on smooth cemented carbide inserts with
cobalt boride interlayer have high adhesive strength and low surface roughness. Diamond-coated
tools with boronization pretreatment have a 5-fold increase in tool life compared with untreated
ones.
Research on Field-Induced Oxidation Processing Technology by Contact-Mode AFM in Ambient Air
Authors: Ji Shi Ming , Zhang L.B. , Zhang Li , Jia X.J. , Yuan Qiao Ling , Yuan Ju Long , Shi J.X. , Wang Ya Liang
Published: March 2009

The mechanism responsible for scanning probe field-induced oxidation in ambient air is
attributed to an electrochemical process, i.e., anodic oxidation or anodization,after the analyses is
given of a surface of a sample exposed to air. The effects of biases, tip speeds on morphology of
field-induced oxidation, are introduced and deduced in the form of kinetics formula of oxidation
growth. The field-induced oxidation of hydrogen-passivated Si (Si:H)using contact-mode AFM in air
at room temperature is investigated. The result achieved from the experiment and that drawn from
theoretical analysis are identical, which indicates the accuracy of the experimental operation.This
experiment suggested that it may be used for further investigation of field-induced oxidation
technology.
Modeling and Real-Time Compensation of Cutting Force-Induced Errors on NC Turning Center
Authors: Wu Hao , Turyagyenda G. , Yang Jian Guo
Published: March 2009

This paper systematically presents the relationship between cutting forced-induced errors
and the spindle motor current basing on kinematic chain of NC machine tools. Constructs the model
of cutting force-induced errors with BP Neural network, and develops the real-time error
compensation system. The compensation effect of this system is verified through the experiment
and the compensation system is of a great importance to precision manufacturing industry.
Design and Performance Study of a 3-DOF Micropositioning Table
Authors: Tian Yan Ling , Zhang Da Wei , Ren Cheng Zu , Yan Bing
Published: March 2009

In order to implement dynamic compensation for the wheel vibration of surface grinding
machine, a micropositioning table with high stiffness and response frequency is designed. The
micropositioning table is driven by three piezoelectric actuators with stiffness of 400 N/μm. Three
capacitive sensors are utilized to form feedback control and flexure hinges are used to guide the
moving part and preload for the piezoelectric actuators. The kinetics of the micropositioning table
has been analyzed to understand the relationship of the control voltage and the posture of the
moving part. Due to the coupling characteristic of the system, the decoupling control method is
introduced to improve the performance of the table. Experimental tests are carried out to investigate
the performance of the micropositioning table.
Experimental Research on High-Speed Machining Pearlitic Gray Cast Iron
Authors: Wan Yi , Liu Zhan Qiang , Ai Xing
Published: March 2009

High-speed machining (HSM) has received great interest because it leads to an increase of
productivity and a better workpiece surface quality. However, tool wear increases dramatically due to
the high temperature at the tool/workpiece interface. Proper selection of cutting tool and cutting
parameters is the key process in high-speed machining. In this paper, experiments have been
conducted to high speed milling pearlitic cast iron with different tool materials, including
polycrystalline cubic boron nitrogen, ceramics and coated cemented carbides. Wear curves and tool
life curves have been achieved at various cutting speeds with different cutting tools. If efficiency is
considered, Polycrystalline Cubic Boron Nitrogen cutting tool materials are preferred in finish and
semi-finish machining. According to the different hardness of cast iron, the appropriate range of
cutting speed is from 850 m/min to 1200m/min.
Research on Ultra-Low Feed Servo Control Technology of Ultra-Precision Machine Based on Semi-Closed Loop Control
Authors: Zhang Fei Hu , Sun X.W. , Dong Shen , Zhang L.J.
Published: March 2009

An ultra-precision machine is developed to machine components made of KDP crystal
with single point diamond fly cutting technique. This paper presents a compensating control
algorithm of error disturbance feed-forward which enhances the stability of ultra-low speed motion
of the semi-closed loop feed control servo system of the machine. The simulation results indicate
that the values of the steady-state tracking error decreases to 1/10 after using the compensating
control algorithm. The fluctuation ratio is less than 4% when machining KDP crystal with the feed
rate of 60μm/s.
Creep Feed Surface Grinding NC Technology by Cup Wheel in Radome Machining
Authors: Zhang Mei Min , Lin Bin , Du F.
Published: March 2009

The radome made of special ceramic is a workpiece needed to be machined precisely.
The machining precision of the exterior contour of the workpiece effects the performance of the
radome directly. Around improving on machining technology of the traditional radome’s
exterior-surface, the creep feed surface grinding by cup wheel based on line enveloping is presented
in this paper. Due to combining the advantages such as large material removal rate, high machining
precision and high efficiency of creep feed grinding and the superiority of cup wheel, the workpiece
with perfect surface quality can be reached. Furthermore, the mathematics model of the geometric
locus of grinding wheel head rotating center is established by using the linear interpolation
algorithm, with a combination of the equal-space and equal-error method. The existing NC grinding
machine with 2-axis simultaneous motion is transformed into 3-axis simultaneous motion (adding
an axis of rotation B) and its feasibility applied to the exterior contour machining has been verified.
The Image Similarity Analysis Technique Applied to the Tool Wear Monitoring in Face Milling
Authors: Liang Yu Teng , Lo C.J. , Chen W.C.
Published: March 2009

The purpose of this paper is to monitor the tool wear based on the image data of cutting
tool in the face milling operation. The surface images of the different coated inserted blade cutters
are captured using a machine vision system incorporating with the mutual information and image
similarity analysis technique for processing the images. The milling test is designed by using
Taguchi’s method. The experimental results indicate that the coating layer factor is recognized to
make the most significant contribution to the over all performance. The TiAlN-surface multilayer
coated inserted blade cutter has the least wear rate amongst these coated milling cutters and has the
longest tool life in this experiment.
Preparation of Nanocrystalline Diamond Films on Molybdenum Substrate by Double Bias Method
Authors: Xu Feng , Zuo Dun Wen , Lu Wen Zhuang , Li Xiang Feng , Xiang Bing Kun , Wang Min
Published: March 2009

The synthesis of nanocrystalline diamond film on polycrystalline molybdenum substrates
was carried out by using of self-made hot filament chemical vapor deposited (HFCVD) system.
Positive bias voltage on the grid electrode on top of hot filaments and negative bias voltage on the
substrate were applied. High purity and extremely smooth nanocrystalline diamond films were
successfully prepared by using the double bias method. Raman, SEM, XRD and AFM results show
that the diamond films obtained have grain sizes less than 20nm, nucleation density higher than
1011cm-1. The mechanism of double bias is also discussed in this paper. The positive grid bias
increases the active, decomposition and ionization of hydrogen and methane molecules, while
negative substrate bias helps positive carbon-containing ions bombard the substrate that leads to the
high nucleation density of the diamond film.
Double-CCD Stereoscopic Vision System Monitoring Chip Shape
Authors: Xu H.H. , Li Xiang Feng , Zuo Dun Wen , Wang Min
Published: March 2009

With the continuous development and popularity of optical sensor and computer vision,
machining process monitoring based on CCD camera has attracted more and more attention in recent
years. Aiming at detecting the shape of cutting chip forming in cylindrical turning, a special matching
algorithm is presented in this paper. As a reliable measuring method of chip shape parameter doesn’t
exist, this algorithm can hardly be verified in a precise manner, however comparison between
experimental results and the original images shows that this matching algorithm is effective. A
double-CCD stereoscopic vision monitoring system employing this algorithm can be used to estimate
the wearing and breakage of tool, and provide significant instruction for the design of tool groove for
its capability of in-process measuring chip shape.
Study on the Two-Axle Bending with Elastic Roller Forming Technique of Non-Circular Cross-Section Tubular Parts Based on the Feed Force Control
Authors: Yan Jing , Zuo Dun Wen , Wang Min
Published: March 2009

Two-Axle Bending Technique with Elastic Roller (TABTER) is a kind of advanced
manufacturing method for bending tubular parts, specially suiting for the difficult-to-work metal
materials with high specific strength, and it can obtain a finer forming accuracy. Now the technique
has been applied to bend split-sleeve and missile body cylinder successfully. In existed theories, the
forming precision of the parts is controlled by adjusting the feed distance between the two axles. But
because of the aging problem of the elastic roller and other uncertain factors, the feed force may be
different even using the same feed, thus the forming precision cannot be ensured. To solve this
problem, the forming theory by controlling the feed force between the two axles is proposed. Then the
NC model of forming the non-circular cross-section tubular parts based on the theory is built. At last,
the NC prototype machine is developed and some experiments are carried out on the machine.
Fabrication of Nanoscale Gratings by Nanoimprint on Silicon Wafer
Authors: Fan X.Q. , Zhang H.H. , Liu S. , Jia K. , Gan Z.Y.
Published: March 2009

This paper presents an approach to fabricate nanoscale gratings by direct imprint on silicon substrate. Imprint conditions that affect the transcription accuracy, such as imprint temperature and pressure, are discussed, and the profile of the imprinted 80nm width gratings with a 250 nm pitch is checked by SEM. High fidelity and fine uniformity demonstrate that nanoimprint is an economical and efficient method to fabricate nanoscale gratings.
Inertial Fusion Micro-Target Semiautomatic Assembly
Authors: Qiu Zu Rong , Nie L.Y. , Zhang Guo Xiong , Yao C.J.
Published: March 2009

This paper describes a micro-target semiautomatic assembly system used in ICF. In the
system two halves of a cylindrical gold hohlraum (1.6 mm long by 0.8 mm in diameter) and a
microsphere capsule (about 0.2 mm in diameter) are assembled. CCD cameras are applied to
monitor the process of closed loop assembly.
Neuron Optimization Based PID Approach for Cutting Force Control
Authors: Jiang S. , Xu Yan Shen , Wu J.
Published: March 2009

To improve the cutting efficiency, one of key approaches is to control with constant force in the full depth working condition. And the controller design is vital to realize the real-time feasibility and robustness of the system. A neuron optimization based PID approach is proposed in this paper and adopted in the NC cutting process. This approach optimizes the parameters of PID controller real-timely with the neural network control principle. It not only overcomes the mismatch of the open-loop system model which occurred in constant PID control, but also solves the contradiction between the calculation speed and precision in the neural network which caused by the node choosing of the hidden layer. At last, the simulation has been carried out on a NC milling machine to prove the validity and effectiveness of the proposed approach.
Control of Shrinkage during Sintering of Alumina Ceramics Based on Master Sintering Curve Theory
Authors: Tatami Junichi , Suzuki Y. , Wakihara Toru , Meguro Takeshi , Komeya Katsutoshi
Published: March 2009

The Master Sintering Curve (MSC) is quite useful for analyzing the shrinkage behavior of ceramics. It is possible to compare shrinkage behavior using MSCs that are obtained from different firing profiles. In this study, shrinkage behavior during sintering of green bodies of several kinds of Al2O3 based ceramics were evaluated, using an electric furnace equipped with a dilatometer to be controlled based on the MSC theory. Although all of the samples shrank monotonically, shrinkage behavior depended on the additive and heating rate. The MSC theory was applied to analyze shrinkage behavior. As a result, a different MSC could be obtained in Al2O3 with and without the addition of MgO. In the pure Al2O3, a single MSC could be obtained from shrinkage curves by firing at a heating rate of 7.5-20oC/min, though the shrinkage curve at a heating rate of 3-5oC/min did not correspond with the MSC. In contrast, shrinkage curves at heating rate of 5-20oC/min were converged in the case of the MgO doped Al2O3 to obtain a unique MSC independent of firing profile. Apparent activation energy for sintering was estimated as 555 kJ/mol in the pure Al2O3 and 880 kJ/mol in the MgO doped Al2O3. The firing profile to obtain a requested sintering shrinkage curve was predicted from the resultant MSC. A comparison between the predicted and the experimental shrinkage curves, showed good consistency, thus confirming that it is possible to control shrinkage behavior using the MSC.
Microwave Sintering BaTiO3 Ceramics Using Liquid Phase Sintering
Authors: Nishimura Yutsuki , Yasuoka Masaki , Nagaoka Takaaki , Kinemuchi Yoshiaki , Watari Koji
Published: March 2009

Microwave sintering is a process in which target materials absorb microwaves and heat themselves from the inside. When microwave energy is effectively absorbed by the material, energy consumption for the sintering can be reduced. Our study is focused on the microwave sintering of BaTiO3 to more rapidly obtain dense ceramics with specific characteristics. For BaTiO3-based electronic components, the sintering temperature is too high for manufacture, so various additives are used to decrease the sintering temperature without undue worsening of the electrical characteristics. In this work, during microwave sintering, BaCO3, H3BO3, BaB2O4 and LiF were added to form a liquid. The effects of the amount of liquid phase on density and dielectric properties were investigated. BaTiO3 sintered with BaCO3 and H3BO3 showed dielectric properties, whereas BaTiO3 sintered with BaB2O4 had semiconducting properties with PTCR characteristics. Also, LiF-added BaTiO3 indicated a dielectric constant in which the peak shifts to lower temperatures with higher LiF concentrations.
Synthesis and Microstructure of TiO2-SiO2 Nanoparticles by a Reverse Micelle and Sol-Gel Processing
Authors: Bae Dong Sik , Kim Byung Ik , Han Kyong Sop , Adair James H.
Published: March 2009

TiO2-SiO2 nanoparticles have been synthesized using a reverse micelle
technique combined with metal alkoxide hydrolysis and condensation. The size of the
particles can be controlled by manipulating the relative rates of the hydrolysis and
condensation reaction of tetraethyl orthosilicate (TEOS) and titanium isopropoxide (TIP)
within the micro-emulsion. The average size of synthesized TiO2-SiO2 nanoparticles was
about in the size range of 20-100 nm. The effects of synthesis parameters, such as the
molar ratio of water to precursor and the molar ratio of water to surfactant, are discussed.
High Pressure / Low Temperature Sintering of Nanostructured Titania by Internal Heating Method
Authors: Chiang Ching Hua , Pae Kook D. , Lu Chung Hsin
Published: March 2009

The feasibility of an internal heating method for the fabrication of large-scale nanostructured TiO2 samples by high pressure/low temperature sintering is studied. The primary apparatus used is a piston-cylinder type. The arrangement inside the die cavity consists of a circular cylindrical green compact, a graphite furnace to heat the sample, an aluminum container to protect the sample and an aluminum silicate or lava tube for electrical insulation. When the sample inside the mold achieved the desired sintering temperature, the temperature of the thermally insulated mold stayed low enough not to damage the mold itself. An obtained cylindrical sample has dimensions of 12.7 mm (1/2 inch) in diameter by 28.6 mm (1 1/8 inch) long. Its average grain size is 64 nm and the Vicker’s hardness is 5.3 GPa.
The Microstructures and Mechanical Properties of Molybdenum Disilicide Preforms Infiltrated by Aluminum
Authors: Zhang Xiao Li , Jin Zhi Hao , Lu Zhen Lin
Published: March 2009

Infiltrant aluminum was infiltrated into molybdenum disilicide preforms in N2 atmosphere at different temperatures by liquid reactive infiltration processing. The mechanical properties and phase composition of these materials were analyzed and discussed. The experimental results showed that the samples were corresponding to 10 at.% Al averagely after sintered, and consisted of Mo(Al,Si)2 phase and Al-Si alloy phase. High infiltration temperature would lead to Al deficiency mainly in Al-Si alloy phase. The highest bending strength of 737 MPa was reached at infiltration temperature of 1350 °C because the sample had fine and integrated grains, and the strong combination between particles. When the infiltration temperature was higher than 1350 °C, the bending strength of material prepared would decrease because of the phase fragmentation.
Oxynitride Glasses and Their Properties - Implications for High Temperature Performance of Silicon Nitride-Based Ceramics
Authors: Hampshire Stuart , Pomeroy Michael J.
Published: March 2009

Oxynitirde glasses are found at triple point junctions and as intergranular films in silicon nitride based ceramics. The glass chemistry, particularly the content of modifyer,usually Y or a rare earth (RE) ion, and the volume fractions of these oxynitride glass phases within the ceramic control the properties of silicon nitride, in particular, creep at high temperature. It is known that, as nitrogen substitutes for oxygen in silicate and aluminosilicate glass networks, increases are observed in glass transition and softening temperatures, viscosities (by two to three orders of magnitude), elastic moduli and microhardness. If changes are made to the RE:Si:Al ratios or different rare earth cation are substituted, properties such as viscosity can be increased by a further two to three orders of magnitude. These effects have implications for the high temperature properties of silicon nitride based ceramics, especially creep resistance. This paper provides an overview of oxynitride glasses and outlines the effect of composition on properties such as glass transition temperature and viscosity and discusses the effects on high temperature behaviour of silicon nitride ceramics.
Influence of Grain Boundary Properties on Microcracking of AlN in Sliding Test
Authors: Kobayashi Yoshimasa , Hayase Toru , Yamada Naohito
Published: March 2009

Grain boundary microcracking in sliding test using a silicon pin was evaluated on several
kinds of AlN to investigate the behavior of damage generation and the influence of material properties
on it. The grain boundary fracture toughness (KIC
gb
) was estimated from a percentage of the
intergranular fracture as a grain boundary property for each specimen. KIC
gb
was greatly influensed by
an amount and kinds of additives. After the sliding test, silicon debris accumulation and grain
boundary microcracking of AlN were observed at the wear traces on the surface of AlN. The density
of grain boundary microcracks increased linearly with increasing the contact load. Empirical
relationship indicated that its density depended on KIC
gb
and the AlN grain size, and decreased mainly
with increasing KIC
gb. The density of grain boundary microcracks greatly degreased at the KIC
gbvalue above 1.9 (MPa·m1/2).
Critical Conditions for Crack-Healing of Structural Ceramics under Constant or Cyclic Stress
Authors: Ono Masato , Nakao Wataru , Takahashi Koji , Ando Kotoji
Published: March 2009

Mullite reinforced by SiC whiskers, Mullite(W), was developed with the aim of improving fracture toughness and to add crack-healing ability. For determining the threshold stress during crack-healing, a composite having a semi-elliptical surface crack of 100 μm was crack-healed at 1473 K for 8 h in air under elevated static and cyclic stresses and the bending strength at 1473 K of the crack-healed composite under stress were also investigated. Mullite(W) crack-healed under static stress below 100 MPa were never fractured during crack-healing and had the same bending strength as the specimens crack-healed under no-stress. Therefore, the threshold static stress during crack-healing of Mullite(W) has been determined to be 100 MPa. The threshold cyclic stress has also been determined to be 150 MPa. Considering that the crack growth is time-dependent, the threshold stress for all conditions during crack-healing of Mullite(W) has been concluded to be 100 MPa.
New Challenge of Plasma Spray Coatings in Nano Oxide Ceramics
Authors: Lee Soo Wohn , Chen Huang , Zeng Yi , Ding Chuan Xian
Published: March 2009

Nanostructured and conventional Al2O3, ZrO2, and TiO2 were deposited using an atmospheric plasma spraying (APS). The size of commercial nano-ceramic powders was varied from 5nm up to 150nm. The microstructure and phase composition of the plasma sprayed coatings on metallic substrate were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that nano-sized ceramic powders enhanced the deposition efficiency on the metallic substrate rather than the micro-sized conventional commercial powders. Density and mechanical property such as microhardness were better in the case of the nano-sized ceramic powders than that of the conventional micro-sized ceramic powders, which are associated with the fine surface roughness and less size in pores of the coating layers. The wear rate of the nanostructured coating was lower than that of the conventional coating. The results were explained in terms of their microstructure of the coatings layers. Also, photocatalytic characterization of the plasma sprayed coatings, using nanocrystalline size TiO2 as feedstock with various powder sizes and shapes as well as adding with different photocatalytic oxides, was performed. The photocatalytic reactivity using plasma sprayed coating layers can be utilized into various applications.
Characterization and Photocatalytic Properties of Plasma Sprayed TiO2 Coatings Deposited from Nanoparticles
Authors: Chen Huang , Kim Tae Ho , Lee Soo Wohn , Aum Ho Sung , Hur Bo Young , Zeng Yi , Ding Chuan Xian
Published: March 2009

The phase and microstructure of four kinds of plasma sprayed TiO2 coatings (P25, ST,
NK, KT) were characterized by XRD (X-ray Diffraction), FE-SEM (Field Emission Scanning
Electron Microscope) and TEM ( Transmission Electron Microscopy). Their photocatalytic
properties were discussed in relation to phase composition and microstructure. The FE-SEM
observation results reveal that there are quite a number of nanoparticles on the surfaces of all four
kinds of plasma sprayed TiO2 coatings, which provide photocatalytic reactive sites. Based on the
observation results of FE-SEM and TEM, the microstructure schematic of plasma sprayed TiO2
coatings using nanoparticles as feedstock is suggested. The best photocatalytic property of P25
coating among the four plasma sprayed TiO2 coatings is attributed to the combination of its fine
“cauliflower” structure and the highest anatase content.
Preparation of Organic/Inorganic Nanocomposites with Microwave Process
Authors: Kim D.H. , Park Seong Soo , Jun B.S. , Lee Jong Kook , Hwang Kyu Hong , Park Hong Chae , Yoon Seog Young
Published: March 2009

Polymer/layered silicate nanocomposities were prepared by in situ polymerization with
microwave process. The influence of the amount of clay on the structure and thermal properties for
the synthesized nanocomposites were characterized by means of X-ray diffraction (XRD),
transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermal
gravimetric analysis (TGA). It was found that the structure of nanocomposites, an
intercalated/exfoliated structure, depended on the clay content.
Preparation of Ceramic Honeycomb Filter Supported Zeolite Membrane Modules by Microwave-Assisted In-Situ Crystallization
Authors: Madhusoodana C.D. , Das Rathindra Nath , Kameshima Yoshikazu , Okada Kiyoshi
Published: March 2009

Ceramic honeycomb filter supported zeolite membrane modules were prepared by a novel microwave-assisted in-situ crystallization method. The synthesis was done in two stages; microwave heating of substrates saturated with precursor solution to form a thin layer of zeolite nuclei (seeds) on the porous substrates followed by hydrothermal treatment to crystallize the ZSM-5 zeolite on the substrates. Zeolite formation was significantly enhanced by comparison with the conventional hydrothermal method, as evident from XRD and BET surface area results. The degree of film formation was varied with varying the dipping time of the substrates in the precursor solution prior to microwave heating, thereby controlling film formation inside the pores of the substrates. This new method of seeding using a simple domestic microwave oven was employed to zeolite membrane modules by forming a zeolite film on the thin walls of a honeycomb filter. The permeability of single gases and the separation of mixed gases were evaluated, showing a low pressure-drop and high permeating flux of light molecule gases.
Sintering Behavior of Microstructured γ-Alumina with Nanosized γ-Alumina Additive
Authors: Oh S.W. , Muto Hiroyuki , Muramoto K. , Minami Wataru , Kim Hee Joon
Published: March 2009

In order to fabricate an alumina ceramics with high density at low sintering temperature, nanosized γ–Al2O3 powders with average size of 9.7 nm were added to microsized γ–Al2O3 powders with 2 #m and they were well mixed. Its sintering behavior was studied in the temperature range of 1000oC to 1300oC and in holding time from 1 hour to 10 hours. Compacted samples with a different mixed ratio of nanosized and microsized Al2O3 powders (N/M ratio) were prepared and pressured at 1 GPa in a uniaxial direction. The phase transformation from γ–Al2O3 to α–Al2O3 takes place at 1100oC for 1hour sintering in all compacted samples. This rate is increased with increasing N/M ratio. The relative density varied from 70% to 95% depending on temperature and N/M ratio. With increasing sintering temperature from 1000oC to 1300oC, it was changed from 70% to 93%. Especially, the relative density was enhanced about 9% higher than that of only microsized sample by only 10 wt% addition of nanosized powders.
Synthesis and Characterization of Calcium Phosphate-AMP Layered Materials
Authors: Kaneno Motoki , Sakamoto Kiyoko , Yamaguchi Shunro , Suganuma Katsuaki
Published: March 2009

Calcium phosphate-AMP layered material was synthesized by the hydrolysis of α−TCP in the presence of AMP at pH=6.2. The resulting composite was a mixture of DCPD and calcium phosphate-AMP layered material. The composition and structures of the calcium phosphate-AMP layered material were estimated based on elemental analysis, thermal analysis, and spectroscopic analyses. About 30 wt% of the composite comprises AMP, which is oriented in alternately layered structure of AMP and calcium phosphate layers. Furthermore, the composite showed better cell adhesion than DCPD.
Dissolution and Mechanical Properties of Sintered Hydroxyapatite Immersed in Water
Authors: Seo Dong Seok , Kim Hwan , Hwang Kyu Hong , Lee Jong Kook
Published: March 2009

Dissolution of hydroxyapatite (HAp) in distilled water and related mechanical properties were investigated. The commercially obtained stoichiometric HAp powders were used as starting materials. After preparing powder compacts, the disks were sintered at 1200oC for 2 h in air with under moisture protection. The sintered specimens were then placed into 40 ml of 7.4 distilled water. After immersing for certain period of time at 37oC, weight loss, microstructure, and mechanical characteristics of the specimens were investigated. Fracture toughnesses were measured for both sintered and immersed HAp for comparison. Evidence for the surface damage was observed with appearance of micron-level of pitting and grain boundaries dissolved. The value for fracture toughness decreased due to dissolution of the materials.
Luminescence Properties of Rare-Earth Doped α-SiAlONs
Authors: Xie Rong Jun , Mitomo Mamoru , Hirosaki Naoto
Published: March 2009

Rare-earth doped Ca-α-SiAlON phosphors, with the compositions of (Ca1-3/2xREx)m/2Si12-m-nAlm+nOnN16-n (RE = Ce, Sm, Eu, Tb, Yb and Dy, 0.5 ≤ m = 2n ≤ 3.0), were prepared by reaction at 1700oC for 2h under 10 atm N2. The concentration of rare earths varied from 3 to 30 at% with respect to Ca. The photoluminescence properties of the powders were investigated at room temperature. The results show that (i) strong visible emissions are observed in rare-earth doped Ca-α-SiAlONs; (ii) the emission properties can be optimized by tailoring the activator concentration and the composition of the α-SiAlON host crystal; and (iii) the yellow Eu2+-doped Ca-α-SiAlON phosphors can be used in warm white LEDs.
A Structural Consideration of a Solid Solution La4Ni3-xMnxO10
Authors: Ueno Shunkichi , Misram Halina B. , Kamegashira Naoki
Published: March 2009

The solubility of manganese ion in layered perovskite La4Ni3O10 phase was examined and
the detailed crystal structure of this phase was discussed. The solid solution of La4Ni3-xMnxO10 was
prepared by solid state reaction. The crystal structure of La4Ni3-xMnxO10 was analyzed by powder
X-ray diffraction and Rietveld methods. The solid solution for x=0.5 had a orthorhombic system with
lattice parameter a=0.5485(0), b=0.5433(6) and c=2.8034(9). In detailed observation of the X-ray
diffraction data, some superlattice reflections that were forbidden for a face centered orthorhombic
cell were identified. A possible space group Pnnn (no.48) was derived from the reflection conditions.
Development of Ferrite Magnetic Materials with High Strength by a Low-Temperature Sintering Method
Authors: Ju Dong Ying , Bian Pei
Published: March 2009

Magnetite (Fe3O4) ferrite magnetic materials have attracted attention arising by the chip
coil electronic material. However, its industrial applications have been limited by the need for high
temperature sintering under reduced pressure or vacuum. In order to develop the process method of
low-cost and energy saving with high-strength and high magnetism of the magnet, in this paper, a new
low-temperature sintering method using CO2 gas and adding a small amount of boric acid (H3BO3) is
proposed. Here, the super fine magnetite powder was fabricated by decomposition from ferrous
oxalate at 500 in CO2 gas. The ferrous oxalate was synthesized using iron chloride and ammonium
oxalate through liquid phase precipitation. The magnetite powder compact was produced by Newton
press and CIP (cold isostatic press) after adding a small amount of boric acid. In this study, the effects
of the additive on the mechanical and magnetic properties of the sintered magnet were also evaluated.
By characteristic evaluation of the magnet, the validity of the proposed new low-temperature sintering
process and the optimal process conditions were confirmed.
Preparation of YSZ Electrolyte for SOFC by Electron Beam PVD
Authors: Shin Tae Ho , Yu Ji Heang , Lee Shi Woo , Han In Sub , Woo Sang Kuk , Jang Byung Koog , Hyun Sang Hoon
Published: March 2009

Yttria stabilized zirconia (YSZ) films with the thickness of up to 12 μm were prepared on
alumina and NiO-YSZ substrates by electron beam physical vapor deposition (EB-PVD). The films
showed nano-scaled columnar structures depending on the substrate temperature. Electrical
conductivity of the YSZ films on alumina was also investigated at the temperature between 700 and
1000oC in oxidizing atmosphere. High activation energy of the conductivity (>1.03eV) indicated that
the conduction via grain boundary controlled the ionic conduction in the films prepared by EB-PVD.
La0.6Sr0.4CoO3-δ as a cathode was applied on the YSZ/NiO-YSZ in order to evaluate the performance
of the YSZ electrolyte.
Current Status of Japanese Passive Control Technology Using Various Damping Materials
Authors: Kasai Kazuhiko , Ooki Yoji
Published: March 2009

Due to the recent earthquakes in the U.S. and Japan, many modern buildings ceased
functioning and required costly structural and nonstructural repairs, although they successfully
protected the lives of the occupants. Because of these, most major buildings constructed after the
earthquakes utilize either passive-control scheme or base-isolation scheme in order to better protect
the building and its contents. This paper addresses current status of passive control technology being
implemented in Japan. Four major groups of dampers and their basic mechanisms are discussed.
Three groups of frames are explained, referring to different connection schemes and deformation lags
between the frame and damper. A unified approach to assess effectiveness of various dampers and
frames will be presented.
Amplitude Dependent Internal Friction of CuAlMn Shape Memory Alloys
Authors: Mielczarek Agnieszka , Riehemann Werner , Vogelgesang Sönke , Zak Hennadiy , Tonn Babette
Published: March 2009

The strain amplitude dependent internal friction at room temperature and the transition temperatures of CuAlMn-shape memory alloys with Al contents from 8.9 wt.% to 12.7 wt.% and Mn contents from 4.7 wt.% to 9.3 wt.% were investigated. The investigated strain range was 10-6 - 10-3. Rods of various compositions were die cast and machined to single clamped damping bars. Their transition temperatures and amplitude dependent damping was determined in as cast and homogenized state. The damping in the investigated shape memory alloys was found to be generally much higher than in metals without martensitic transition. In as cast state some alloys exceeded the damping of a Sonoston type alloy measured in comparison for strains higher than 3 x 10-5. The influence of grain size on damping was investigated by additional sand casting and the use of Boron for grain refinement. It was found that only the material with the biggest grains had a noticeable higher damping over the whole measured strain range. Homogenization heat treatment can still extremely increase the damping of CuAlMn alloys. After homogenization this extremely high damping decreases slowly to medium values in the order of as cast alloys.
Effect of Thermal Cycling (γ<->ε) on Martensitic Transformation Kinetics and Damping Capacity of Fe –17mass%Mn Alloy
Authors: Lee Young Kook , Seo Young Seob , Jin Won , Choi Chong Sool
Published: March 2009

Effect of thermal cycling(γ↔ε) on γ→ε martensitic transformation kinetics and damping
capacity of Fe-17mass%Mn alloy has been studied. The amount of ε martensite increases with
thermal cycling in spite of decrease in Ms temperature. The increase in ε martensite content with
thermal cycling is attributable to an increase in the density of martensite nucleation sites by
introduction of dislocations during thermal cycling. The γ→ε martensitic transformation kinetics
shows a burst mode in the non-cycled specimen, while the kinetics exhibits a sigmoidal mode in the
cycled specimens. The damping capacity of the alloy increases with increasing the ε martensite
content in the non-cycled specimen. On the contrary, the damping capacity of the alloy decreases
with increasing the ε martensite content in the cycled specimens. The reason is that the dislocations
introduced during thermal cycling, which obstruct the movement of the damping sources, become
more with thermal cycling.
The Resonant Vibration Fracture Characteristics of Al-xZn Alloy and Mg-xAl-Zn Alloy
Authors: Hung Fei Yi , Chang Han Wen , Chen Zong Fu , Lui Truan Sheng , Chen Li Hui
Published: March 2009

Both Al-Zn alloy and Mg-Al-Zn alloy have been considered as high damping and light materials. For practical use, this study investigated the effects of the structure and the composition on the vibration fracture characteristics of the Al-xZn alloy and the Mg-xAl-Zn alloy under resonance. For Al-xZn (x=7, 11, 49, 83wt%) alloys, under both constant force and initial-deflection conditions, the 7Zn showed the greatest vibration life. For Mg-xAl-Zn (x=3, 6, 9wt%) alloys, experimental results indicate that the AZ31-F as-extruded samples showed a greater vibration life, while high Al fully-annealed samples (AZ91-O) had greater vibration fracture resistance under constant force conditions.
Development of Lead-Free Piezoelectric Materials Using Domain Wall Engineering
Authors: Wada Satoshi , Yako Koichi , Muraishi Tomomitsu , Kakemoto Hirofumi , Tsurumi Takaaki
Published: March 2009

For the [111] oriented barium titanate (BaTiO3) single crystals, the patterning electrode was applied to induce the finer engineered domain configurations with domain size of 3 2m. The poling treatment was performed at 134 °C under electric fields below 6 kV/cm to inhibit the burning of the patterning electrode with photoresist. As the results, the gradient domain sizes from 3 to 8-9 2m were induced into the 31 resonator. The d31 was measured at -243.2 pC/N, and this value was almost 70 % of the expected d31 of –337.7 pC/N for the resonator with domain size of 3 2m. This difference was originated from lower applied electric field below 6 kV/cm. However, this study was revealed that the patterning electrode was very powerful tool to induce much finer domain sizes below 5 2m.
Preparation of LiFePO4 as a Cathode Material for Lithium Ion Batteries by a Citric Acid Complex Method
Authors: Higuchi Masashi , Uchida Kaori , Katayama Keiichi , Azuma Yasuo
Published: March 2009

LiFePO4 powders were prepared by a citric acid complex method. The effects of source composition and firing conditions on the formation of LiFePO4 were investigated. Single phase and well-crystallized LiFePO4 powders were obtained at 500°C for 5h. The particle size of the obtained powder is smaller than that of powder prepared by the conventional solid-state reaction method.
Orientation Control of Perovskite Epitaxial Thin Film on Silicon Substrate with Yttria-Stabilized Zirconia Buffer Layers
Authors: Kondo Masao , Kurihara Kazuaki
Published: March 2009

The influence of a rare earth oxide/yttria-stabilized zirconia (YSZ) double buffer layer structure on
the orientation of a perovskite thin film was investigated on (100) silicon substrates. A calcium
titanate perovskite film with a mixture of (110) and (100) orientation was grown epitaxially on a
YSZ buffer layer. Since rare earth oxides have almost the same chemical nature and different lattice
parameters, it is anticipated that the lattice parameter of the buffer layer can be controlled by
changing the rare earth element. An (100) oriented epitaxial calcium titanate film was obtained by
changing the composition of rare earth oxides on the YSZ/Si substrate.
A Comprehensive Assessment of Motor Function for Use at Home
Authors: Kim Cheol Seung , Eom Gwang Moon , Kim Sung Min , Lim Choon Hak
Published: March 2009

This study aims at developing a comprehensive assessment method of motor function
practicable for use at home. The motor function can be thought of as the resultant of many categories
of fitness, so that a comprehensive assessment technique is desirable. In this study, the motor function
is evaluated in terms of cardiorespiratory fitness and the muscular fitness. The cardiorespiratory
fitness is assessed by the estimated maximum O2 consumption rate and the total heart beat index. The
muscular fitness is assessed by the maintenance time of the maximum speed cycling. The suggested
method is evaluated on the young athletes and also on the non-athletic young subjects. Both the
cardiorespiratory and muscular fitness of two groups showed significant difference. It is expected that
the suggested method be useful for a comprehensive evaluation of the motor function at home.
Measurement of Elastic Properties of Self-Oscillating Gel
Authors: Aoki Reiko , Enoki Manabu , Yoshida Ryo
Published: March 2009

Self-oscillating gel is designed by copolymerizing the catalyst for the Belousov-
Zhabotinsky (BZ) reaction with thermosensitive polymer. The cylindrical-shaped specimens of
NIPAAm-co-(Ru(bpy)3 gel were prepared by copolymerizing (Ru(bpy)3) monomer as catalyst with
NIPAAm as thermosensitive polymer. Tensile tests were performed with cross-head speed of 10 )m/s
in pure water at 20°C. Stress-strain curves were plotted using tensile load measured by semiconductor
gauge and strains calculated from observation of the gel. Fracture strain and Young’s modulus were
obtained from these curves. Also Poisson’s ratio was estimated from the ratio of strains in
longitudinal and radial directions.