bluuebunny/crossref_metadata_2025 huggingface dataset:
An Overview of the Microstructures Present in High-Speed Steel -Carbides Crystallography
Authors: Serna M.M. , Jesus Edilson Rosa Barbarosa , Galego E. , Martinez Luís Gallego , Corrêa H.P.S. , Rossi J.L.
Published: March 2009

The aim of the work was to prepare an overview about the microstructures present in
high-speed steel, focused on the crystallography of the carbides. High-speed steels are currently
obtained by casting, powder metallurgy and more recently spray forming. High-speed steels have a
high hardness resulting from a microstructure, which consists of a steel matrix (martensite and
ferrite), in which embedded carbides of different crystal structure, chemical composition,
morphology and size, exist. These carbides are commonly named MxC, where M represents one or
more metallic atoms. These carbides can be identified by X-ray diffraction considering M as a
unique metallic atom. In this work, it is discussed, in basis of the first principles of physics
crystallography, the validation of this identification when it is considered that other atoms in the
structure are substitutional. Further, it is discussed some requirements for data acquisition that
allows the Rietveld refinement to be applied on carbide crystallography and phase amount
determination.
Recycling of Steel Sludge into Red Ceramic
Authors: Andrade P.M. , Vieira Carlos Maurício Fontes , Monteiro Sérgio Neves , Vernilli Jr. F.
Published: March 2009

The present paper has for objective to evaluate the effect of fine steel sludge waste
incorporation on the properties and microstructure of a kaolinitic clayey body used to the
fabrication of bricks and roofing tiles. Compositions were prepared with additions of waste of
0, 5 and 10 wt.% in a kaolinitic clay from the county of Campos dos Goytacazes, State of Rio
de Janeiro, Brazil. To determine the technological properties such as bulk density, linear
shrinkage, water absorption and flexural strength, specimens were prepared by uniaxial
pressure at 20 MPa and then fired in a laboratory furnace at 700°C, 900°C and 1100°C. The
microstructure of the fired specimen was evaluated by SEM. The results showed that the
incorporation up to 10 wt. % of fine steel sludge does not change the ceramic properties,
specially, at low temperatures. Hence, the recycling of steel sludge into red ceramic
fabrication can be considered as an environmentally correct solution for the final disposal of
this type of waste.
Phase Transition Behaviour of Tricalcium Phosphate (TCP) Doped with MgO and TiO2 as Additives
Authors: Wolff D.M.B. , Ramalho E.G. , Acchar Wilson
Published: March 2009

In this study, the tricalcium phosphate [β-Ca3(PO4)2] behaviour using MgO and
TiO2, respectively as additives has been investigated. The introduction of these additives is to
control the phase transition of TCP during thermal process. The tricalcium phosphate (β,α)
phases change when the temperature of sintering increase and/or during cooling down. To
investigate the phase transition we examined tricalcium phosphate powder doped using 5 mol
% of MgO or TiO2. The β-TCP and additives powders were mixture with acetone and dried
using rota-vapour to eliminate all the solvent at 45°C for 3 h. After this procedure the powders
were uniaxially pressed at 50 MPa and sintered in air-atmosphere at 1100°C to 1200°C for 5
h. All the sintered compacts were measurements by relative density, porosity, shrinkage,
shrinkage rate, and the polished and fracture surfaces were investigated using a scanning
electron microscope (SEM). To verify the transition phase the differential thermal analysis
(DTA) and X-ray diffraction studies were carried out. The experimental results of relative
density showed 92 % (MgO) and 90 % (TiO2) at 1200°C.
Sintering of Cobalt and Strontium Doped Lanthanum Chromite Obtained by Combustion Synthesis
Authors: Setz L.F.G. , Corrêa H.P.S. , Paiva-Santos Carlos de Oliveira , de Mello-Castanho Sonia Regina Homem
Published: March 2009

Lanthanum chromite (LaCrO3) is one of the most adequate materials for use as
interconnector in solid oxide fuel cell (SOFC) applications, due to its intrinsic properties,
namely its good electrical conductivity and resistance to environment conditions in fuel cell
operations. Due to difficulties in sintering, additives are usually added to help in the
densification process. In this work, the influence of added cobalt and strontium, in the
sintering of LaCrO3 obtained by combustion synthesis was studied. The starting materials
were respectively nitrates of chromium, lanthanum, cobalt and strontium, and urea was used
as fuel. The results show that by increasing the strontium and cobalt concentrations it is
possible to reduce the temperature of sintering. Using both additives, the sintering processes
took place in lesser times than normally used for this material, as well as greater values of
density were attained.
Chemical, Electrochemical and Morphological Characterization of Poly-{trans-[RuCl2(vpy)4]} Films Deposited on Nd-Fe-B Magnets and on Inert Materials
Authors: Bandeira M.C.E. , Crayston J.A. , Franco César V.
Published: March 2009

The characterization of poly-{trans-[RuCl2(vpy)4]}films, deposited on Nd-Fe-B magnets and on Pt, Au and Glassy Carbon (GC) electrodes, produced in the present work were carried out by several in situ and extra situ techniques, aiming by the understanding of film structure improve its use as corrosion protection coating and/or electrocatalyst. Cyclic Voltammetry (CV) was used to estimate the surface coverage, film stability and the surface redox potential of films produced at different conditions. By Chronocoulometry films diffusion coefficient (Dct) were evaluated. Film morphology was studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Chemical composition analyses were carried out by Energy Dispersive Spectroscopy (EDS), X-ray Photonelectron Spectroscopy (XPS) and Raman Spectroscopy. The results indicated that the film structure is similar to the Ru complex in solution. Films Dct is limited by the electron transfer rate between Ru metallic centers. Films on Nd-Fe-B were composed by Ru3+ whereas on Pt by Ru2+.
Prediction of Spring Back of the Two-Axle Rotary Shaping Based on Neural Network
Authors: Lu Shi Hong , Wang Jing
Published: March 2009

Two-axle rotary shaping is one of advanced sheet metal forming process that combined
stamping ascendant used elastic medium with traditional rotary shaping principle. The prediction
model of two-axle rotary shaping is set up to predict the springback for two-axle rotary shaping. It
used the back propagation neural network because of the better nonlinear mapping ability. Some of
data from the experiment and FEM simulation is applied to train the network; the other data is used to
test the prediction result. The result showed that the value of prediction and experiment is in good
agreement, and just small error is existed. It demonstrated that the neural network model might
predict the springback of two-axle rotary shaping and reduce the number of simulation calculation
and experiment operation. It can offer a powerful guidance for rapid choice of process parameters in
production.
Research on the Problem of MC Assembly Line Balancing Based on Genetic Algorithm
Authors: Yang Shui Li , Huang Wei Ping
Published: March 2009

Through the comparative analysis, the features of the mass customization assembly line are obtained. The corresponding genetic algorithm is designed with the total idle time and overloading time of the minimized assembly line as the target function, which is used to resolve the distribution problems of the operation elements in mass customization assembly line. The improved genetic operators can heighten the overall optimal solution ability of genetic algorithm convergence. The calculated examples indicate that this algorithm is the effective method for seeking out solution to the problems of operation elements in the mass customization assembly line.
Study on Ultra-Precision Ball Surface Floating Polishing Kinematics Mechanism
Authors: Lv Xun , Yuan Ju Long , Wen Dong Hui , Deng Qian Fa , Lou Fei Yan
Published: March 2009

The high precision balls are requested in national defense, astronautics and high-tech
commercial domain urgently. Conventional precision machining methods are sensitive to uniformity
of abrasives and machining environment. After precision machining, there are easily to produce thick
damaged layer on the ball surface because of machining stress and chemical conversion. On the basis
of the floating polishing mechanism, a new scatheless ultra-precision polishing method of ball surface
can solve the problems of abrasives uniformity effectively and damaged layer. In order to ensure that
the new polishing method polishes ball surface equally, the appropriate angular velocities of the ball
should be selected. This paper sets up the mathematical model about the motion of ball. By analyzing
and simulating the relationship of the angular velocities, the best processing parameters are acquired.
Laser Fabrication of Low Resistivity Electrode on Glass
Authors: Wu Dong Jiang , Zhuang Juan , Wang Xu Yue , Kang Ren Ke , Zhao Fu Ling
Published: March 2009

A method for low resistivity resistor on transparent substrate with laser induced plasma assisted by ablation and laser annealing was described. The diffusion distribution for metallization was measured with XPS. The surface profile was analysed with SEM. The minimum resistivity we got was 0.1 /Sq. It demonstrates that the electronic thin film obtained has a very good conductivity. The most important factors for forming electrically conducting films on the transparent substrate are laser fluence, beam scanning and pulse repetition rate. This technology will be useful in the fabrication of LCD electrode, glass defused resistor and circuit on glass.
Research on Nano-Cutting Processes Based on Parallel Molecular Dynamics
Authors: Liang Ying Chun , Li De Gang , Bai Qing Shun , Tang Yu Lan
Published: March 2009

To investigate the effect of tool geometry on single-crystal silicon nano-cutting, parallel
molecular dynamics (MD) simulations are carried out with different tool rake angles. In this study,
a parallel arithmetic based on mechanism of spatial decomposition together with MD is applied to
simulate nano-cutting processes of single-crystal silicon (100) plane by using a single-crystal
diamond tool. The simulation results show that tool rake angle has great effects on cutting forces
and subsurface stress, and the effect of tool rake angle variation on work-piece potential energy is
not evident while cutting single-crystal Silicon (100) plane. Moreover, the analysis of cutting forces
and potential energy show that there is not evident dislocation in the nano-cutting.
Fabrication of Patterned Metal Films on Organic Substrates by Transfer Printing
Authors: Dong Shen , Zhao Xiao Li , Wang Jing He , Li Zheng Qiang , Sun Tao , Liang Ying Chun
Published: March 2009

Here a simple and direct method based on transfer printing has beep developed, in which
rigid stamps transfer metal films deposited on the relief surface of the stamps onto patterned organic
substrates. Ultra-precision machining technology is combined with conventional photolithography to
fabricate patterned Si stamps and organic substrates by replica molding. Experiment results indicate
that patterned metal films on Silicon stamps were successfully transferred onto PDMS substrates.
Fabrication of patterned metal films on organic substrates by transfer printing may suit for fabricating
sub-micrometer and nanometer scale features in a single process.
Research on the 5-axis Machining of Blisk
Authors: Hu Chuang Guo , Zhang Ding Hua , Ren Jun Xue , Yang Lei
Published: March 2009

The study presents a new method for 5-axis machining of blisk, which consists of both
roughing tunnels and finishing blades. The ruled surface is used to approximate the freeform
surface of blade, and the boundary contour of the tunnel is then determined. Based on the double
point offset method, the 5-axis tool paths for roughing blisk tunnel region are generated. Similarly,
by linking the corresponding points on the tool center curves and the tool axis drive curves, the
spiral tool paths are developed to finish milling thin-walled blades taking into account the residual
stresses induced part distortion during machining. This strategy is experimentally verified.
Experimental Investigation on Friction Performance of Mechanical Seals with a Laser-Textured Seal Face
Authors: Yu Xin Qi , Liu Mei Hong , Wang Zhen Hui , Peng Pei Ying , Cai Ren Liang
Published: March 2009

Regular micro-surface structure in the form of micro-pores produced on the face of mechanical seals by laser technology can be used to improve the friction performance of the seal mating rings. A test rig with variable axial load was used to test laser-textured seal rings with micro-pores of various pore depth and pore ratio to study the effect of the laser-textured seal face structure parameters on the friction performance of mechanical seals. It is found that there are optimum texturing face parameters at which the friction torque and the face temperature rise of seal rings are minimum. Results of these tests show that the micro-pores on one of the seal mating faces can generate substantial hydrodynamic effect. Heat generation due to frictional contact on seal-ring surfaces is a major factor that causes deterioration of face seals and shortens their service life[1,2]. Excessive temperature rise can be avoided by improving structure of a seal surface. By means of laser technology return-flow structure, oblique line groove and spherical micro-pores are engraved on the seal face[3-5]. The research shows that substantial hydrodynamic effect can be generated between the seal faces with micro-pores[6-8]. In this study experiments are performed on laser-textured micro-pores seal faces at various axial loads to investigate the effect of the face structure and operating parameters on friction torque and face temperature rise.
Sintered Fe3Al Intermetallic - A New Filter Element for Hot Gas Filtration
Authors: Xing Yi , Kuang Xing , Wang Fan , Kuang Chun Jiang , Fang Yu Cheng
Published: March 2009

Hot gas filtration and purification is widely applied in many industrial fields, such as in power generation industry, chemical and petrochemical industry, metallurgical industry, ceramic and glass industry, environmental protection industry, etc. Gas filtration at high temperature from industrial processes offers various advantages such as increasing process efficiency, improving heat recovery and materials resource recovery, protection of downstream plant equipment, etc. At the same time, it is an advanced environment protection technology. This paper describes a newly developed metallic filter element - sintered Fe3Al intermetallics. The manufacturing process of sintered Fe3Al metallic powder and the mechanical and filtration characteristics of this filter element were investigated. In this work, the mechanism of the morphological and phase constituent changes of the Fe3Al powder during sintering were studied. The newly developed filter elements were found to have excellent corrosion resistance, good thermal resistance, high strength and high filtration efficiency. Based on these results, the potential application of the sintered Fe3Al filter elements in industrial hot gas filtration are discussed.
Microstructure Control of Porous In-Situ Synthesized Si2N2O-Si3N4 Ceramics
Authors: Paul Rajat Kanti , Lee Chi Woo , Kim Hai Doo , Lee Byong Taek
Published: March 2009

Using 6wt%Y2O3-2wt%Al2O3 as sintering additives and Si as a raw powder, the continuously porous in-situ Si2N2O-Si3N4 bodies were fabricated by multi-pass extrusion process and their microstructures were investigated depending on the addition of carbon (0-9wt %) in the mixture powder. The introduction of Si2N2O fibers observed in the unidirectional continuous pores as well as in the pore-frame regions of the nitrided bodies can be an effective method in increasing the filtration efficiency. In the case of no carbon addition, the network type Si2N2O fibers with high aspect ratio appeared in the continuous pores with diameters of 150-200nm. However, in the case of 9wt% C addition, the fibers were found without any network type and had diameters of 200-250nm.
Powder Characteristics and Sintering Behavior of SiO2 Coated BaTiO3
Authors: Park Jae Sung , Han Young Ho
Published: March 2009

The Powder characteristics and sintering behavior of SiO2 coated BaTiO3 were studied.
BaTiO3 powders were synthesized by the liquid mix method developed by Pechini, and silica coating
was prepared by alkoxide hydrolysis method with TEOS and ethanol. The particle size of the BaTiO3
powders was ~35 nm and the thickness of the SiO2 coating layer was ~5 nm. As the SiO2 content
increased, the SiO2 layers improved the powder dispersion by increasing electrostatic repulsion
between the BaTiO3 particles. The Zeta potential of SiO2 coated BaTiO3 was getting close to that of
pure silica with a more negative charge, compared with that of the uncoated BaTiO3. The onset
temperature of shrinkage curves shifted to higher temperatures with increasing SiO2 contents.
Preparation and Characterization of LnTaO4 (Ln = La, Nd, Sm, Dy, Er and Tm)
Authors: Fujita Atsushi , Matsushita Hiroaki , Katsui Akinori
Published: March 2009

Lanthanide tantalite LnTaO4 (Ln= La, Nd, Sm, Dy, Er and Tm) was synthesized by a
solid state reaction between mixed powders of Ln2O3 (Ln=La, Nd, Sm, Dy, Er and Tm) and Ta2O5.
The single-phase LnTaO4 was prepared by sintering at temperatures of 1423-1673 K in air. The
SEM observation showed that the particles were provided with the growth steps and the depeloped
facets. The photocatalytic activity for water splitting of LnTaO4 prepared was measured under UV
light irradiation. The activity obtained was higher than that previously reported. These results
suggested the crystallinity of LnTaO4 photocatalysts correlates closely with the efficiency of water
splitting.
Sintering and Mechanical Properties of Chromium Boride - Chromium Carbide Composites
Authors: Matsushita Junichi , Shimao Kenji , Machida Yoshiyuki , Takao Takumi , Iizumi Kiyokata , Sawada Yutaka , Shim Kwang Bo
Published: March 2009

Several boride sintered bodies such as TiB2, ZrB2, and SiB6 were previously reported. In
the present study, the sinterability and physical properties of chromium boride (CrB2) containing
chromium carbide (Cr3C2) sintered bodies were investigated in order to determine its new advanced
material. The samples were sintered at desired temperature for 1 hour in vacuum under a pressure
by hot pressing. The relative density of sintered bodies was measured by Archimedes’ method. The
relative densities of CrB2 addition of 0, 5, 10, 15 and 20 mass % Cr3C2 composites were 92 to 95 %.
The Vickers hardness of the CrB2 with 10 and 15 mass % Cr3C2 composites were about 14 and 15
GPa at room temperature, respectively. The Vickers hardness at high temperature of the CrB2
addition of 10 mass % Cr3C2 composite decreased with increasing measurement temperature. The
Vickers hardness at 1273 K of the sample was 6 GPa. The Vickers hardness of CrB2 addition of
Cr3C2 composites was higher than monolithic CrB2 sintered body. The powder X-ray diffraction
analysis detected CrB and B4C phases in CrB2 containing Cr3C2 composites.
Test Results of SMC Cores as Some Types of Motor Cores
Authors: Asaka Kazuo , Ishihara Chio , Enomoto Yuuji , Ito Motoya
Published: March 2009

Recently, SMC(Soft Magnetic Composite) materials were studied for their applications in
many fields. We have developed a superior SMC for use as motor cores and are studying their
applying effects [1]. It shows almost the same motor output power as laminated Si-steels of 0.35mm
in thickness, although core loss of SMC is about 1.5 times that of the laminations. As shown in the
results, the SMC motor core is sufficient for real use as a motor core. Furthermore, a 3-D shaped
motor core made of SMC can improve approximately 20% of the output compared with the same
size motor made of laminations.
Synthesis of Ultra Fine TiC Powders by Carbothermal Reduction
Authors: Kim Beom Seob , Woo Young Chul , Kim Deug Joong
Published: March 2009

Synthesis of nano TiC powder by carbothermal reduction procedure of TiO2 was
investigated. TiO2 was mixed with resin or carbon powder as reduction agent and was reacted at
1500oC for 0 ~ 45 minutes under Ar atmosphere. Conglomeration of the powders mixed with TiO2
and resin were observed in the initial stage of the reduction and the unreacted TiO2 was not found
even after 5 minutes elapsed. The fine TiC particles with a size of 80 nm were formed by complete
reaction between Ti, a reduction product, and C after 15 minutes. However, the conglomerated
particles were not the powders added with carbon powder as carbon source in the initial stage. The
unreacted TiO2 particles were kept for 15 minutes. Finally, TiC particles were formed and were
partially grown after 20 minutes.
Displacement Properties of Newly Developed 3-Dimensional Piezoelectric Actuator at Various AC Frequencies
Authors: Yoon Man Soon , Choi Y.G. , Ur Soon Chul
Published: March 2009

The electromechanical properties of a newly proposed 3-dimensional piezoelectric actuator have been investigated. Especially, the effects of 3-dimensional geometry on the maximum tip displacement were carefully investigated. As a result, it was found that the maximum strain of the 3-dimensional piezoelectric device was significantly enhanced up to 4.5 times higher than that of a disk shape device. This data was in good agreement with the finite element model analysis of strains and vibration modes. Moreover, the field -induced displacement stability of dome-shaped 3- dimensional piezoelectric actuator at various ac freguencies was superior to Rainbow actuator.
Interfacial and Surface Characterization of Fluorine Treated SnAgCu and NiTi Powders and NiTi/SnAgCu Composite Materials
Authors: Silvain Jean François , Binot C. , Durand E. , Demourgues A.
Published: March 2009

NiTi shape memory alloy particles have been incorporated inside SnAgCu lead free solder paste in order to improve the mechanical performances of solder paste. However, because of the non-wetting properties of solid NiTi particles by the liquid SnAgCu matrix, the development of fluorine gas treatment of both NiTi and SnAgCu particles has been optimized. Scanning electron microscopy (SEM) micrographs of NiTi/SnAgCu composite materials have shown that “Fluorine treatment” of SnAgCu powders lead to a huge increase of the NiTi powder content inside the liquid SnAgCu matrix where no effect have been observed when NiTi materials are fluorinated. Xray photoelectron spectroscopy analysis of treated SnAgCu powders have been used in order to analyze surface chemistry evolution where wavelength dispersion spectroscopy line profiles, across NiTi-SnAgCu interfaces, have been performed.
The Influence of Production Process Parameters on the Properties W-Ag, Mo-Ag Composites
Authors: Leżański Jan , Madej Marcin
Published: March 2009

Attempts have been made to describe the influence of production process parameters on
the microstructure and properties of W - Ag and Mo - Ag composites. The compositions of powder
mixtures are W + 30% Ag and Mo + 30%Ag. Silver additions assists densification during sintering
by a liquid phase sintering process. The main goal of this work is to compare properties and
microstructure of as-sintered and as-infiltrated composites.
Microstructure and Sintering Behavior of ZnO Thermoelectric Materials Prepared by the Pulse-Current-Sintering Method
Authors: Shikatani Noboru , Misawa Tatsuya , Ohtsu Yasunori , Fujita Hiroharu , Kawakami Yuji , Enjoji Takashi
Published: March 2009

Thermoelectric elements using environment-friendly materials with high thermoelectric
conversion efficiency and of these thermoelectric elements can be increased by using a structure
combining n-type and p-type semiconductors. From the above point of view, attention was
directed at ZnO as a candidate n-type semiconductor material and investigations were made. As the
result, a dimensionless figure of merit ZT close to 0.28 (1073K) was obtained for specimens
produced by the PCS (Pulse Current Sintering) method with addition of specified quantities of TiO2,
CoO, and Al2O3 to ZnO. It was found that the interstitial TiO2 in the ZnO restrains the grain growth
and CoO acts onto the bond between grains.
Tungsten/Copper Functionally Graded Materials: Possible Applications and Processing through the Powder Metallurgy Route
Authors: Ozer O. , Missiaen J.M. , Pascal Celine , Lay Sabine , Chaix Jean Marc , Mitteau Raphael
Published: March 2009

Processing of W-Cu graded materials from attritor-milled W-CuO mixtures is described.
The powder reduction steps are investigated by TG and XRD analyses and by microstructural
observations (SEM, TEM). Sintering of reduced powder with different compositions is analysed by
dilatometry. Sintering behaviour of the graded component processed by co-compaction of a
10/20/30wt%Cu multi-layer material is briefly discussed. Liquid Cu migration is observed and
smoothes the composition gradient. Perspectives to control this migration are discussed.
Anisotropy of Thermal Expansion Coefficient of Pressed Graphite Foam Measured over the Temperature Interval 20-500°C
Authors: Zerrouk I. , Ionov S.G. , Popov V.P. , Hamamda S.
Published: March 2009

This research is aimed at determining the thermal expansion coefficient, α(T), along
three directions, X, Y, and Z, of a graphite sample pressed along the direction of weak interactions
(Z), over the temperature range [25-500°C]. The experiment results showed that pressing
completely alters the dilatometric behavior of the material, and the shape of the α(T) curve changes
significantly from one direction to another. Comparing αX, αY, and αZ, a strong anisotropy in the
thermal expansion coefficient is observed. This is in good agreement with results published by other
researchers who have shown that the electrical conductivity and thermal conductibility of a similar
material exhibits strong anisotropic behavior. Pressing has also led to anisotropy in the basal plane,
i.e. between αX and αY which have opposite signs. [Pressing results in a significant decrease in α(T)
along the Y axis, which is considerably lower than that reported in the literature. αZ is clearly
higher that of non-pressed graphite. The wide divergence among the three coefficients is believed to
be attributed to the intensification of the membrane effect.
Consideration of Fe Nanoparticles and Nanowires Synthesized by Chemical Vapor Condensation Process
Authors: Ha Jong Keun , Cho Kwon Koo , Kim Ki Won , Nam Tae Hyun , Ahn Hyo Jun , Cho Gyu Bong
Published: March 2009

Various physical, chemical and mechanical methods, such as inert gas condensation, chemical vapor condensation, sol-gel, pulsed wire evaporation, evaporation technique, and mechanical alloying have been used to synthesize nanoparticles. Among them, chemical vapor condensation(CVC) represents the benefit for its applicability to almost materials because a wide range of precursors are available for large-scale production with a non-agglomerated state. In this work, iron nanoparticles and nanowires have synthesized by chemical vapor condensation(CVC) process, using iron pentacarbonyl(Fe(CO)5) as precursor. The effects of processing parameters on the morphology, microstructure and size of iron nanoparticles and nanowires were studied. Iron nanoparticles and nanowires having various diameters were obtained by controlling the inflow of metallic organic precursor. Both nanoparticles and nanowires were crystallized. Characterization of obtained nanoparticles and nanowires were investigated by using a field emission scanning electron microscopy, transmission microscopy and X-ray diffraction.
Surface Densification Coupled with Higher Density Processes Targeting High-Performance Gearing
Authors: Hanejko Francis , Rawlings Arthur , King Patrick , Poszmik George
Published: March 2009

This paper will describe a powder and processing method that facilitates single presssingle
sintered densities approaching 7.5 g/cm³. At this sintered density, mechanical properties of
the powder metal (P/M) component are significantly improved over current P/M technologies and
begin to approach the performance of wrought steels. High performance gears have the added
requirement of rolling contact fatigue durability that is dependent upon localized density and
thermal processing. Combining high density processing of engineered P/M materials with
selective surface densification enables powder metal components to achieve rolling contact fatigue
durability and mechanical property performance that satisfy the performance requirements of many
high strength automotive transmission gears. Data will be presented that document P/M part
performance in comparison to conventional wrought steel grades.
The Elastic Behaviour of Metal Powder Compacts
Authors: Prado Jose Manuel
Published: March 2009

In this work the elastic behaviour of metallic powder compacts is studied. Cylindrical
specimens with different levels of density have been submitted to uniaxial compression tests with
loading and unloading cycles. The analysis of the elastic loadings shows a non linear elasticity
which can be mathematically represented by means of a potential law. Results are explained by
assuming that the total elastic strain is the contribution of two terms one deriving from the hertzian
deformation of the contacts among particles and another that takes into account the linear elastic
deformation of the powder skeleton. A simple model based in a one pore unit cell is presented to
support the mathematical model.
Metal and Ceramic Micro Components Made by Powder Injection Molding
Authors: Piotter Volker , Finnah G. , Zeep B. , Ruprecht Robert , Haußelt Jürgen
Published: March 2009

To overcome the lack of micro manufacturing processes suitable for medium and large
scale production as well as to process high resistive materials a special variant of micro injection
molding is currently under development: micro powder injection molding (MicroPIM), which
already enables the manufacturing of finest detailed components with structure sizes down to a few
ten micrometer. In order to expand the scope of application of MicroPIM, tests are being conducted
with pure tungsten powders or tungsten alloy powders. As further improvement, micro twocomponent
injection molding allows, for example, the fabrication of micro components consisting
of two ceramic materials with different physical properties.
Metal Injection Molding Process of Mo2FeB2 Boride Base Cermets
Authors: Tashiro Hirofumi , Hirata Koro , Yamasaki Yuji , Takagi Kenichi
Published: March 2009

Mo2FeB2 boride base cermets produced by a novel sintering technique, called reaction
boronizing sintering through a liquid phase, have excellent mechanical properties and wear and
corrosion-resistances. Hence, the cermets are applied to the injection molding die-casting machine
parts and so on.
Metal injection molding (MIM) is a suitable processing route for the mass production of
complex shaped and high performance components. In general, it is difficult for the liquid phase
sintered materials to be applied to the injection molding process because significant shrinkage and
deformation occur during sintering.
In this study, the MIM process was applied in the production of Mo2FeB2 boride base cermets
parts. We investigated that the effect of deoxidization and sintering temperature on mechanical
properties and deformation of the cermets. As a result, deoxidization temperature of 1323K and
sintering temperature of 1518K were suitable. The MIM products of the cermets showed allowable
dimensional accuracy and the same mechanical properties as the press-sintered.
Optimization of Composite MIM Feedstock Rheological Behaviour by Experimental Analysis
Authors: Chen Chih Cherng , Wu Chi Wen , Yen Chih Ming
Published: March 2009

The kneading process and formulations of feedstock obviously affect the quality of MIM
products. In the present work, the rheological behaviour of the composite MIM feedstock, metal
matrix (Cu) with few additions of ceramic powders (Al2O3), was measured by a selfdesigned/
manufactured simple capillary rheometer. Experimental results show that the distribution
between powders and binder is more uniformly when blending time increased. Though high powder
loading will increase the feedstock viscosity, the fluidity reveals relatively stable through the load
curves of extrusion. Besides, the temperature-dependence of viscosity of the feedstock
approximately follows an Arrehnius equation. Basing on Taguchi’s method, the kneading
optimization conditions and the rheological model of the feedstock were established, respectively.
Spray Forming of Mg2Si Rich Aluminum Alloys
Authors: Ellendt N. , Uhlenwinkel Volker , Stelling O. , Irretier A. , Kessler O.
Published: March 2009

Aluminium Alloys with a 22 wt.-% Mg2Si content were spray formed. This alloy features a low density and is therefore a superior material for lightweight applications. The main problem in the spray forming of this type of alloy was the occurrence of high porosities. First process optimizations have been performed to decrease porosity under a certain level, so that it can be closed by an extrusion process.
Abnormal Grain Growth Mechanism of Calcium Hexaluminate Phase
Authors: Song Jun Ho , Jo Young Jin , Bang Hee Gon , Park Sang Yeup
Published: March 2009

Calcium-hexaluminate phase(CA6) phase is known to be effective for the crack shielding due to the spinel block crystal structure. In this study, we focused to control the CA6 morphology for the good damage tolerance behavior in alumina and zirconia/calcium-hexaluminate(CA6) composites. calcium-hexaluminate(CA6) composites were prepared from zirconia, alumina and calcium carbornate powders. Calcium-hexaluminate(CA6) phase was obtained by the solid reaction through the formation of intermediate phase(CA2). CA6 phase showed column type abnormal grain grown behavior composed of small blocks. Due to the typical microstructure of CA6, alumina and zirconia/calcium-hexaluminate composites provide well controlled crack propagation behavior.
Influence of Sintering Parameters on the Mechanical Performance of PM Steels Pre-Alloyed with Chromium
Authors: Bergman Ola , Lindqvist Björn , Bengtsson Sven
Published: March 2009

Powder grades pre-alloyed with 1.5-3 wt% chromium are suitable for PM steel
components in high performance applications. These materials can be successfully sintered at the
conventional temperature 1120 °C, although well-monitored sintering atmospheres with low oxygen
partial pressures (<10-17-10-18 atm) are required to avoid oxidation. Mechanical properties of the Cralloyed
PM grades are enhanced by a higher sintering temperature in the range 1120-1250 °C, due
to positive effects from pore rounding, increased density and more effective oxide reduction. A
material consisting of Astaloy CrM, which is pre-alloyed with 3 wt% Cr and 0.5 wt% Mo, and 0.6
wt% graphite obtains an ultimate tensile strength of 1470 MPa combined with an impact strength of
31 J at density 7.1 g/cm3, after sintering at 1250 °C followed by cooling at 2.5 °C/s and tempering.
Research on Two Sintered Techniques of Nanometer WC-Co Powder
Authors: Sun Lan , Jia Cheng Chang , Tang Hua
Published: March 2009

This paper concerned with SPS (spark plasma sintering), hot pressing of sinter nanometer
WC-Co powder and discussed the density, hardness, microstructures and grain sizes of the alloys
sintered by different styles. The results showed that SPS could lower the sintering temperature,
increased the density and circumscribed the growth of grain size of WC. Hot pressing sintering
could produce high density alloys and play well on the grain growth, but its sintering temperature
and sintering time were larger than SPS. Besides, the hardness of the sintered cemented alloys that
was dependent on the grain size and densification could also be improved by SPS and hot pressing.
Fabrication of Cordierite Honeycomb from Fly Ash
Authors: Kim Sung Jin , Park Sung Jin , Bang Hee Gon , Park Sang Yeup
Published: March 2009

In the study, we attempted to synthesize the cordierite by the reaction of fly-ash
and alumina, silicon dioxide, magnesia powders. And also porous cordierite honeycomb filte
r for air purification was fabricated from the combination of synthetic cordierite using fly as
h and pore forming agent. As the extrusion processing parameters of honeycomb, binder formul
ation and extrusion conditions were investigated. Graphite addition was effective for the reduce
ment of extrusion pressures. Porous cordierite honeycomb was fabricated with high porosity (
58%), and good compressive strength (69MPa) with 30wt% graphite at low sintering tempera
ture(1150oC).
Sinter-Bonding of Iron Based Compacts Containing P and Cu
Authors: Pieczonka Tadeusz , Kazior Jan
Published: March 2009

The sinter-bonding behavior of iron based powder mixtures was investigated. To produce the green compacts to be joined the following powders based on Höganäs AB grade NC 100.24 plain iron powder were used: NC 100.24 as delivered, PNC 30, PNC 60 and NC 100.24 + 4%Cu powder mixtures. Dimensional behaviour of all those materials during the sintering cycle was monitored by dilatometry. Simple ring shaped specimens as the outer parts and cylindrical as the inner parts were pressed. The influence of parts’ composition on joining strength was established. Diffusion of alloying elements: copper and phosphorous, across the bonding surface was controlled by metallography, SEM and microanalysis.
HRTEM Study of Phase Transformation from Anatase to Rutile in Nanocrystalline TiO2 Particles
Authors: Kim Kyou Hyun , Park Hoon , Ahn Jae Pyong , Lee Jael Chul , Park Jong Ku
Published: March 2009

The spherical anatase TiO2 nanoparticle of 50 nm in diameter was manufactured by flame method and was subsequently heat-treated to investigate the transformation behavior from anatase to rutile using TEM observation. The anatase particle was facetted at the free surface and a neck formed between the anatase particles prior to the phase transformation. This resulted in the severe lattice distortion at the region of the interface. Unfortunately, we could not find the rutile grain nucleated in the anatase particle due to very fast grain growth. All the phase boundaries observed in HRTEM images existed in the contact between anatase and rutile particles. The nucleation of rutile phase in anatase particle was suppressed at the low heat-treated temperature but the grain growth of rutile particles after the phase transformation grew very fast by the sweeping phenomena of grain boundary. It leaded to the microstructure without the rutile phase traped in anatase particle.
A Comparative Study of Mechanical Property in Al-8Fe-2Mo-2V-1Zr Bulk Alloys Fabricated from an Atomized Powder and a Melt Spun Ribbon
Authors: Jung Taek Kyun , Sung T.J. , Kim Mok Soon , Kim Won Yong
Published: March 2009

Al-8Fe-2Mo-2V-1Zr alloy powders were prepared by gas atomization and melt spinning
method. In melt spinning technique, melt spun ribbons were pulverized by a speed rotor mill to make
a powder shape. In order to produce a bulk form, powders were canned and hot extruded in the
extrusion ratio of 25 to 1 at 693K. For the gas atomization and hot extrusion processed bulk material,
equiaxed grains with the average size of 400 nm and finely distributed dispersoids with their particle
sizes ranging from 50nm to 200nm were observed to display a characteristic nano-structured feature
over the entire region. For the melt spun and hot extrusion processed alloy, a refined microstructural
feature consisting of equiaxed grains with the average size of 200 nm and fine dispersoids with their
particle sizes under 50 nm appeared to exhibit a difference in microstructure. Yield strength of the
latter alloy was higher than that for the former alloy up to elevated temperatures. The maximum yield
strength was measured to about 800 MPa at room temperature for the latter alloy.
Extrusion of CP Grade Titanium Powders Eliminating the Need for Hot Pre-Compaction via Hot Isostatic Pressing
Authors: Wilson Robert , Stone Nigel A. , Gibson Mark A.
Published: March 2009

Extrusion is a way to produce near net shape components from CP grade titanium
powders of optimum density with minimum porosity and acceptable mechanical properties.
Chemically pure, hydride/dehydride titanium powders were cold pre-compacted and extruded at
850oC under an argon atmosphere. The extrusion stress required was ~450MPa. To characterize
the extrusions, the porosity distribution, qualitative microstructure and tensile properties were
evaluated and compared with conventional extruded wrought titanium. Extrusion occurred after
the green billets were upset to ~100% of theoretical density and adequate lubrication was applied to
the die. The resultant product was 100% dense with a narrow band of surface porosity and
exhibited an equiaxed microstructure of similar magnitude to the starting material. The tensile
properties of the bars were observed to be significantly superior to conventionally extruded CP
titanium bar products, a result associated with the much finer average grain size. Outcomes from
this study have assisted in the identification of a number of key characteristics important to the
extrusion of titanium from pre-compacted CP titanium powders, allowing the elimination of
canning and hot isostatic pressing (HIPping) of billets prior to extrusion as per conventional PM
processes.
Milling and Sintering Behavior of the Metal-Ceramic Mixed Powders
Authors: Yang Z. X. , Youn Sang Heum , Hwang Kyu Hong , Yoon Seog Young , Lee Jong Kook , Kim Hwan
Published: March 2009

The reaction-sintered alumina ceramics with low firing shrinkage were prepared from Al/Al2O3 powder mixture by attrition milling and the effect of milling characteristics of raw powders on reaction sintering was investigated. Powder mixtures of flaky shape Al with coarse alumina was much more effectively comminuted by the attrition milling than the mixtures of globular shape Al with coarse alumina powders. Furthermore the coarse alumina was much more useful in pulverizing and grinding the ductile Al particles than fine alumina. After attrition milling and isopressing at 400MPa, the Al/Al2O3 specimen was oxidized at 1200°C for 8 hours followed by sintering at 1550°C for 3 hours. Because mixed powder of coarse alumina with flaky Al was much more effectively comminuted than the globular Al, sintered body of more than 97% theoretical density was achieved, but low contents of Al leads to relatively higher shrinkage of about 8%. As the coarse alumina particles are much more useful in cutting and reducing the ductile Al particles, the use of the coarse alumina powder was much more effective in reaction-sintering.
Corelationship Between Powder Metallurgy and Casting Method Using SiC Powder for Metal Foam
Authors: Kim Sang Youl , Babcsán Norbert , Ahn Duck Kyu , Song Yeong Hwan , Hur Bo Young
Published: March 2009

Metal foams are not easy to use as materials as their manufacturing process involves all
three, solid, liquid and gaseous phases occurring simultaneously at varying temperatures and
moreever the morphology of the solidified foam is quite complex. There has not been any report on
the stabilization of metal foams. To compare the stabilisation of metal foams using a different
method, powder metallurgy and casting method using SiC and Ca alloy particle are required. Our
investigation results showed deeply etched valleys with high oxygen content and secondary phases
attached to line-shaped pores with higher SiC content than the matrix. These line-shaped pores -
most probably oxide bifilms-form networks decorated with either secondary phases or oxide
particle. We suspect that these decorated bifilms play a crucial role in the stabilisation of metal
foams.
Fabrication of Gas-Permeable Die Materials Having Orthogonally Arrayed Pore Channels
Authors: Chan Tien Yin , Wang De Xing , Chang Hua Jun , Chen Chia Liang
Published: March 2009

Defects of components as a result of entrapped gases during an injection process could be minimized with the utilization of a gas-permeable metal die material in the mold, due to its excellent permeability of air. Conventional gas-permeable die materials employ low temperature sintering of loosely packed steel powders with or without the addition of pore-forming polymers, whose microstructures are usually weak and their gas permeability values are also low. In this study, gas-permeable metal die materials are developed using tool steel powder, packed in a mold having the insertion of orthogonally arrayed polymer wires. Linear gas-permeable channels in orthogonal array are thus developed by the burning out of the polymer wires, which yield a large value of air permeability. The value of air permeability can be adjusted by changing the diameter and number density of the polymer wires. The tool steel powder can be made fully dense by supersolidus liquid phase sintering, yielding a microstructure with a wear resistance value much larger than that of the conventional gas-permeable die material.
Net-Shape Manufacturing of Micro Porous Metal Components by Powder Injection Molding
Authors: Nishiyabu Kazuaki , Matsuzaki Satoru , Tanaka Shigeo
Published: March 2009

A novel production method for porous metal components has been developed by
applying powder space holder (PSH) method to metal powder injection molding (MIM) process.
The PSH-MIM method has an industrial competitive advantage that is capable of net-shape
manufacturing the micro-sized porous metal products with complicated shapes and controlled
porosity and pore size. In this study, the small impeller with homogeneous micro-porous structure
was manufactured by the PSH-MIM method using porous compounds composed of fine stainless
steel 316L powder and polymethylmethacrylate (PMMA) particle. The effects of combinations in
size and fraction of PMMA particle on dimensional tolerance and variation of sintered porous
specimens were investigated. It was concluded that the PSH-MIM method could manufacture
commercially micro-porous metal components with high dimensional accuracy.
Processing of Polymer-Derived Microcellular Ceramics Containing Reactive Fillers
Authors: Kim Young Wook , Jang Doo Hee , Eom Jung Hye , Song In Hyuck , Kim Hai Doo
Published: March 2009

Processing techniques for producing microcellular silicon carbide, mullite, and cordierite ceramics with cell densities greater than 108 cells/cm3 and cells smaller than 30 μm have been developed by a reaction method that incorporates a polysiloxane and reactive fillers. The techniques developed in this study offer substantial flexibility for producing microcellular ceramics whereby cell size, cell density, degree of interconnectivity, composition, and porosity can all be effectively controlled. It is demonstrated that the adjustment of filler composition enables the possibility of tailoring the composition and properties of the microcellular ceramics. The present results suggest that the proposed novel processing techniques are suitable for the manufacture of microcellular ceramics with high morphological uniformity.
Recycling of Stainless Steel Grinding Sludge
Authors: Shimizu Toru , Hanada Kotaro , Adachi Satoru , Katoh Masahito , Hatsukano Kanichi , Matsuzaki Kunio
Published: March 2009

Stainless steel sludge is generated as a waste in the grinding process, and the possibility
of recycling stainless steel is considered here. Generally, stainless steel grinding sludge ranging
about 10,000 are generated per a year in Japan, and most of it is discarded or re-melted with scrap
steel. In this study, we considered the possibility of using the stainless steel sludge as metal powder
for MIM or raw material for metal foam. For the MIM process, the metal powder will need some
improvement, and flotation and spheroidizing processes of the sludge are necessary. For fabrication
of the metal foam, untreated sludge can be used, and steel foam about 90% porosity is produced.