bluuebunny/crossref_metadata_2025 huggingface dataset:
Interfacial Coatings on Inorganic Fibers for High Temperature Ceramic Matrix Composites
Authors: Baklanova Natalia I. , Zima Tatyana , Titov Anatoly , Zaitsev B.N.
Published: March 2009

Ceramic matrix composites reinforced by carbon or SiC-based fibers achieve high toughness
and damage tolerance through the disposal of weak fiber coating which can deflect cracks and promote
debonding at the fiber/matrix region. The methods for fabrication, as well as different techniques
including SEM/EDS, XPS, XRD, AFM, micro Raman for evaluation of properties of the interphase zone
are considered. The morphology, composition, topography, roughness, tensile properties of coated carbon
and SiC fibers are discussed in details. The behavior of coated fibers is governed by the chemistry,
procedure for coating fabrication, nanostructural factors.
Effects of Phosphorus and Fluorine on the Crystallization and Structure of CaO-A12O3-SiO2 System Glass-Ceramic
Authors: Cheng Jin Shu , Qiu Hui Guang , Li Hong , Xie Jun
Published: March 2009

CaO-A12O3-SiO2 (CAS) system glass-ceramics were prepared by sintering with certain
amount of yellow phosphorus slag. The effects of phosphorus and fluorine on the nucleation, crystallization
and structure of CAS system glass-ceramics were investigated by differential thermal analysis, X-ray
diffraction, scanning electron microscopy and other measuring methods. Glass-ceramics of CAS system
with 42.32wt% yellow phosphorus slag were obtained by nucleating at 615°C for 1 hour and crystallizing
at 926°C for 2 hours. The results showed that the introduction of phosphorus and fluorine promoted the
nucleation and crystallization of glass-ceramics, lowering the crystallizing temperature. The main crystal
phase of glass-ceramics was β-wollastonite. The density of the glass-ceramic was 2.695g/cm3.
Microstructure and Crystallization Kinetics Analysis of MO-B2O3-Al2O3-SiO2(M=Mg, Ca, Ba) Glass-Ceramics
Authors: Liu Hua Bin , Xiao Han Ning , Luo Yao Ju , Liao Hong Wei , Chen Hai Bo
Published: March 2009

The effect of alkali earth metal oxides MO (M=Mg, Ca, Ba) on the crystallizing behavior and
the microstructure of B2O3-Al2O3-SiO2 system (BAS) were studied. DSC, XRD and SEM were used to
analyze the crystallization kinetics and to characterize the crystal phases and microstructures of the
glass-ceramics. MO can effectively facilitate the formation of BAS glass, and the crystallinity of the glass
increases in the order of MgO < BaO < CaO. For one given MO, the crystallinity of the glass is dependent
on B2O3/SiO2 ratio: the lower the ratio is, the weaker the crystallinity of the glass will be. It was found that
the early crystallization is aluminum metaborate (Al4B2O9) when the glass is heated at 800 °C, and it
would transfer into aluminum borate(Al18B4O33) at temperatures over 1000 °C. The activation energy and
the Avrami exponent of Al4B2O9 were calculated by Ozawa formulation.
Effect of ZrO2 on Mechanical and Biological Properties of Calcium Phosphate-Based Glass-Ceramics for Biomedical Applications
Authors: Zheng Cai Yun , Li Shu Jun , Hao Yu Lin , Yang Rui
Published: March 2009

The effect of ZrO2 addition on mechanical and biological properties of bioactive
glass-ceramics with chemical compositions of 60CaO-30P2O5-3TiO2-xZrO2-(7-x)Na2O (x=0,1,3) was
investigated. It was found that ZrO2 addition up to 3 mol% contributes to monotonical increase of the
glass transition temperature. The micro-hardness increases slightly by 1 mol% ZrO2 addition and keeps
constant with further addition whereas 1 mol% ZrO2 addition results in ~20% increase of three-point
bending strength. When the specimens were soaked in simulated body fluid, complete apatite layers were
formed on the specimens regardless of the ZrO2 addition. It is therefore concluded that the toughening
contribution of 1 mol% ZrO2 addition has no adverse effect on the bioactivity of calcium phosphate
glass-ceramics.
Effect of Calcination Temperature on Mineral Composition of Carbide Slag, Lime Activity and Synthesized Xonotlite
Authors: Cao Jian Xin , Liu Fei , Lin Qian , Zhang Yu , Dong Yong Gang , Zeng Ling Ke
Published: March 2009

The calcined carbide slag was used to prepare xonotlite by replacing quicklime as the
calcareous materials. Effects of calcination temperature on the mineral composition of the carbide slag,
lime activity and synthesized xonotlite were studied. The results indicated that carbide slag after proper
calcination can be used to prepare xonotlite. Calcination temperature has no effect on the synthesized
xonotlite, but has a great impact on lime activity and morphology of secondary particles of xonotlite.
Preparation and Thermal Decomposition Mechanism of Sr2+-Doped Mg,Al-Hydrotalcite Nanocrystalline
Authors: Ren Qing Li , Luo Qiang
Published: March 2009

The highly pure nanocrystalline Mg,Al-hydrotalcite with Sr2+ doping was synthesized by the
one-step liquid reaction method at atmospheric pressure. And the preparation of the Sr2+-doped
Mg,Al-hydrotalcite nanocrystalline was investigated according to the results of XRD, TEM, Raman and
DSC. Moreover, based on the DSC test results, the thermal mechanism functions of the
Mg,Al-hydrotalcite with Sr2+ doping are studied in detail after calculation and comparison.
Phase Structure and Microstructure of the Interface between WC Steel Bond Hard Alloy and Carbon Steel
Authors: Wei Shi Zhong , Li Yan , Gao Jian Ping , Ji Ying Ping , Long Rui
Published: March 2009

WC steel bond hard alloy powders were compacted by explosive compaction on the surface of
carbon steel, then the composite layer was prepared by liquid-phase sintering in vacuum. The phases and
microstructures of the interface of composite layer were observed by SEM, EDS, TEM. Result showed
that the thickness of the interface was about 30μm, and the elements of W, Cr, C were detected in the
interface. The structures of the interface were pearlites which were composed of the layered tablets of
M23C6 and ferrite. The layered tablets were perpendicular to the interface. The structures were the
pearlites and ferrites in the side of the carbon steel near the interface but globular carbides, whose phase is
W3Fe3C, and pearlites in side of steel bond hard alloy. During sintering at 1623K, all elements of
metal-powder and C, V, which were decomposed by hard-phase, interdiffused in the interface. The
multiple carbides were found in the interface and steel bond hard alloy. As a result, the powders formed
into compact alloy by itself, and at the same time there was a good metallurgical bonding between the
carbon steel and the hard alloy.
Low Temperature Sintering Ba3Ti5Nb6O28 Ceramics with Tunable Temperature Coefficient of Dielectric Constant
Authors: Guo Dong , Ling Zhi Yuan , Hu Xing
Published: March 2009

A middle permittivity dielectrics with the tunable temperature coefficient of dielectric constant (τε) in the BaO-TiO2-Nb2O5 system, Ba3Ti5Nb6O28, has been synthesized and characterized. The dielectric properties of Ba3Ti5Nb6O28 measured at 1MHz are as follows: dielectric constant (εr) ~38, dielectric loss (tanδ)<0.0002, temperature coefficient of dielectric constant (τε)~-22ppm/°C. The Ba3Ti5Nb6O28 phase satisfies the requirements of NP0 (MLCC) dielectrics, but the sintering temperature of the Ba3Ti5Nb6O28 phase (1250~1300°C) is too high to be co-fired with Ag or Cu electrodes. To lower the sintering temperature, an appropriate amount of ZnO-B2O3 frit (5~7wt.%) was added to the Ba3Ti5Nb6O28 phase and dense ceramics were obtained at the sintering temperature lower than 1000°C. Furthermore, the CaNb2O6 phase with the positive τε of 65ppm/°C was incorporated into the Ba3Ti5Nb6O28 phase to adjust the temperature coefficient of dielectric constant from negative to positive(-22~30ppm/°C). Near zero τε ceramics with high εr (38) and low tanδ (0.0002) were obtained at the composition of Ba3Ti5Nb6O28/ CaNb2O6/ ZB frit=76:17:7 wt.%.
Effect of Residual Stress on the Mechanical Capacity of Layered Composite
Authors: Han Dae Suk , Lee Chi Seung , Chun Min Sung , Kim Myung Hyun , Park Hong Chae , Lee Jae Myung
Published: March 2009

For enhanced mechanical properties of ceramics for structural application, a great deal of
attention has concentrated on preparation of layered composites. In this study, numerical simulation
technique, which is applicable for the evaluation of mechanical performance for layered composite
material, was developed. A generalized material constitutive equation coupled with material damage
model based on the continuum damage mechanics approach was proposed and has been implemented
to an in-house type finite element analysis code. The material behaviors for each component of
layered composites can be simulated by the pre-defined material model on the simulation. A series of
finite element analyses was carried out in order to elucidate the effect of fabrication related residual
stress on the structural capacity of the layered composites.
Structure and Microwave Properties of NaxCa1-xAl2-xSi2+xO8 (0 < x < 0.67) Plagioclase Feldspar
Authors: Li Wei , Yue Zhen Xing , Zhao Fei , Pei Jing , Li Long Tu
Published: March 2009

The plagioclase feldspar (NaxCa1-xAl2-xSi2+xO8, 0<x<0.67), has been synthesized under
sub-solidus conditions using the solid-reaction technique. X-ray diffraction (XRD) was used to study the
temperature dependency of the phase and structure transformations. Scanning electron microscopy (SEM)
was performed to demonstrate the micro-structure of the sintered samples. The dielectric properties in
microwave (MW) frequency region, including the dielectric constant, Qxf and the temperature coefficient
were measured by the microwave network analyzer. The results revealed the value of Qxf decreases when
0≤x≤0.2, while increases when 0.2≤x≤0.67. The lowest value of Qxf was at x = 0.2.
(1-x)(K0.44Na0.52Li0.04)(Nb0.84Ta0.10Sb0.06)O3-xSrTiO3 Lead Free Piezoelectric Ceramics
Authors: Cao Ming He , Wang Wan Qiang , Yu Zhi Yong , Hao Hua , Liu Han Xing
Published: March 2009

(1-x)(K0.44Na0.52Li0.04)(Nb0.84Ta0.10Sb0.06)O3-xSrTiO3 (KNNT-ST) lead free piezoelectric
ceramics have been synthesized by a solid state reaction method. The effect of SrTiO3 content on the
piezoelectric properties, sintering behavior and microstructure of (1-x) KNNT-x ST ceramics was
investigated. The experimental results showed that the addition of SrTiO3 can restrain the volatilization of
Na ions and K ions and improve relative density of the samples. A morphotropic phase boundary between
orthorhombic and tetragonal phases is found in the composition range of 0.03<x<0.05. The piezoelectric
properties can be enhanced for (1-x) KNNT-x ST ceramics near the morphotropic phase boundary.
Fabrication and Characterization of Li2O Excess (Na0.49K0.49Li0.02)(Nb0.8Ta0.2)O3 Piezoelectric Ceramics
Authors: Kim Min Soo , Kim Sin Woong , Jeong Soon Jong , Song Jae Sung
Published: March 2009

Dense Li2O excess (Na0.49K0.49Li0.02)(Nb0.8Ta0.2)O3 [NKLNT] ceramics were developed by
conventional sintering process without any special technique. The electrical properties of NKNLT
ceramics were investigated as a function of Li2O concentration. When the sample sintered at 1050 oC for
4 h with the addition of 1 mol% Li2O, electro-mechanical coupling factor (kP) and piezoelectric
coefficient (d33) were found to reach the highest values of 0.42 and 260 pC/N, respectively.
Morphotropic Phase Boundary Study of the BNT-BKT Lead-Free Piezoelectric Ceramics
Authors: Zhao Wei , Zhou He Ping , Yan Yong Ke , Liu Dan
Published: March 2009

A lead-free piezoelectric ceramic binary system based on bismuth sodium titanate
(Bi0.5Na0.5)TiO3 (BNT)-bismuth potassium titanate (Bi0.5K0.5)TiO3 (BKT) was synthesized by
conventional mixed-oxide technique. The XRD analysis showed that the rhombohedral-tetragonal
morphotropic phase boundary (MPB) of the Bi0.5 (Na1-xKx)0.5 TiO3 system was in the composition range
of x = 0.16 ~ 0.20. In addition, the piezoelectric properties of this system were also investigated. It was
indicated that the piezoelectric properties are better with the compositions near the rhombohedral phase
within the MPB than the compositions near the tetragonal phase.
A Piezoelectric Micropump Based on MEMS Fabrication
Authors: Wang Bao Wei , Chua Xiang Cheng , Li Long Tu
Published: March 2009

This paper presents a valve-less micropump which is actuated by a piezoelectric ceramic chip.
We employ a microelectromechanical system process for the silicon substrate and anodic bonding for
assembly of the Pyrex glass and silicon wafer. The reciprocating type micropump contains two
nozzle/diffuser elements and a silicon membrane with an embedded piezoelectric ceramic actuator.
Effect of Annealing on Laser-Ablated K3Li2-xNb5+xO15+2x Thin Films
Authors: Zhan Zu Sheng , Gong Yan Sheng , Wang Chuan Bin , Shen Qiang , Zhang Lian Meng
Published: March 2009

In this study, K3Li2-xNb5+xO15+2x (KLN) thin films were prepared by laser-ablated a sintered ceramic target. For an optimum deposition condition, in-situ post annealing method was employed on as-deposited films. XRD measurements showed that KLN films with (310) preferred orientation were obtained on fused quartz substrate. Surface morphology studies indicated that in-situ post annealing could improve the surface quality of KLN thin films. The average transmittance of as-deposited and annealed films in the visible range was nearly 80% to 90%.
Sintering of Transparent Polycrystal Nd:YAG with MgO as Additive
Authors: Li Yong Chao , Guo Wang , Lu Tie Cheng , Tong Shi Hong , Fang Rui Xiao , Xu Hui
Published: March 2009

In this paper, pure phase Nd-doped YAG powders were prepared by co-precipitation method
with different amount of MgO (0~ 0.6 wt %) as additive. Transparent Nd:YAG ceramics were fabricated
by vacuum sintering at 1750°C for 10 hours using the powders. Microstructure of the surfaces of
thermally etched Nd:YAG ceramics was observed by SEM. Transmittance of the transparent Nd:YAG
ceramics was measured over the wavelength region from 600nm to1200nm. The results showed that
MgO as sintering aid can restrain abnormal grain growth and reduce pores in grains and at the same time,
optical transmittance of the ceramics was increased. The optimal weight percentage of MgO added can be
determined as 0.3wt % for the fabrication of transparent Nd:YAG ceramics.
Synthesis and Hydrogen Storage Capacity of SiC Nanotube
Authors: He Rong An , Chu Zeng Yong , Li Xiao Dong , Si Yong Min
Published: March 2009

Hollow nanostructures have important applications in the field of gas adsorption, separation and storage due to their large specific surface areas. Silicon carbide nanotubes (SiCNTs) are one kind of such materials. In this paper, SiCNTs were synthesized from multiwalled carbon nanotubes (MWCNTs) via chemical vapor reaction (CVR) and purification. The SiCNTs were characterized by XRD, SEM and TEM. The results revealed that C-SiC nanotubes were obtained after CVR and most carbon were removed after purification with some traces retained inside SiCNTs. Hydrogen storage capacities measurements indicated that SiCNTs are superior to MWCNTs.
Dielectric Performance of Alumina Ceramics Sintered at Different Temperatures
Authors: Ding Li Jian , Tu You Ping , Li C.R. , Wang Jing Chun
Published: March 2009

This paper investigated the influence of sintering temperature on the dielectric performance of
alumina ceramic. Three different kinds of alumina ceramic samples were prepared using the same
formula with three different sintering temperatures. The flashover voltage and surface charge distribution
of the test samples were measured with a finger type electrode system under a positive pulse voltage
application in a 1×10-4Pa vacuum circumstance. The experimental results showed that the samples with
higher sintering temperature have worse dielectric performance. Based on the SEM observation, the
change of dielectric performance could be attributed to the change of microstructure of alumina ceramics.
Effects of Mn-Doping on the Piezoelectric and Ferroelectric Properties of (Na0.8K0.2)0.5Bi0.5TiO3 Ceramics
Authors: Jiang Xiang Ping , Li Long Zhu , Jiang Fu Lan , Zheng Yan Yan , Liu Li Hua
Published: March 2009

Lead-free piezoelectric ceramics of (Na0.8K0.2)0.5Bi0.5TiO3+x wt.% Mn (abbreviated as NBKT-x% Mn, x=0~0.5) were synthesized by solid-state reaction. The grain growth of the ceramics was restrained by Mn-doping at a certain extent. The mechanical quality factor Qm increases and the dielectric loss tanδ decreases with the increase of Mn-doping. Best piezoelectric properties were obtained for the composition of NKBT-0.2%Mn: d33=158 pC·N-1, tanδ=2.9% at 1 kHz, Qm=110 and kp=30%. The P-E loops show that remnant polarization Pr and coercive field Ec decrease slightly with the amount of the Mn2+ increasing up to 0.2wt.% and then increase as the content of Mn2+ increases further. NKBT-0.5wt. % Mn exhibits strong ferroelectricity with remnant polarization Pr = 38μC/cm2.
Influence of Processing Parameters on Manufacturing Al2O3 Parts by Extrusion Gelation Freeform Fabrication
Authors: Yu Zhi Yong , Liu Han Xing , Cao Ming He , Ouyang Shi Xi , Huang Yong
Published: March 2009

Extrusion gelation freeform fabrication process is an extrusion-based freeforming technique
capable of fabricating complex shaped monolithic ceramic prototypes by the sequential deposition and
solidification of ceramic suspensions from a computer aided design model. In this process, ceramic parts
are produced using an extrusion nozzle suitable for extruding ceramic suspensions. In this study, the
processing parameters influencing on manufacturing Al2O3 parts were discussed. Air pressure on top of
suspensions, rotating speed of screw, nozzle diameter and scan speed are the main factors to influence the
dimensional precision of ceramic bodies. By optimizing these processing parameters, the green bodies
were fabricated with high precision. The sintered samples with homogenous microstructure and ~97.6%
relative density could be prepared by sintering of these green bodies at 1600oC for 2 hours.
Mullite Fiber Reinforced Alumina Ceramic Matrix Composites
Authors: Wang Zhi , Shi Guo Pu , Sun Xiang , Hou Xian Qin
Published: March 2009

Mullite fiber reinforced alumina ceramic matrix composites (MFACC) were prepared using CaO-MgO-SiO2 (CMS) and TiO2 as sintering aids. The effects of the contents of sintering aids and mullite fiber on the density and sintering temperature of MFACC are studied. The results showed that when the CMS content is 8.0% and the TiO2 content is 1.0%, the density of the as-sintered MFACC is 98.9%. When the mullite fiber content is 15.0% and the sintering temperature is 1450 °C, the flexural strength of the resultant composite increases to 504.5MPa, 70.7% higher than the original matrix, and the relative density of the composites reaches 98.4%. The reinforcement mechanisms are fibers pull-out and sticky point.
Precision Grinding of Concave Spherical Surface of High-Alumina
Authors: Zhang Xiao Feng , Lin Bin , Zhang Fang Yang
Published: March 2009

The performances of high-alumina ceramic are analyzed such as physical and mechanical
property. In consideration of its brittleness-ductility change, the critical cutting depth agc of high-alumina
ceramic is 3μm. When the cutting depth of single grain is less than the critical cutting depth of alumina
ceramic in precision manufacturing, the material is wiped off with ductility. So the cutting depth of single
grain agm should be selected within 0.1~2.5μm.Grinding wheel sharp edge is utilized for the spherical
surface generation cutting. The ceramic-bonded fine grain diamond wheel is selected after considering
manufacturing technology, machining parameters, its making and mending. The granularity of grinding
wheel is M1~M5 and the consistence is 125%. The method of spherical surface generation cutting and the
effect of high-alumina ceramic ductile machining were verified by the experiment of high-alumina
ceramic precision grinding using precision grinding machine MGK1420. The result shows that the
surface quality is very high and achieves the requirements.
Preparation of SiCw/3Y-ZrO2/Al2O3 Composites
Authors: Xu Hong Liang , Wang Hai Long , Lu Hong Xia , Liu Xiao Fang , Yang Dao Yuan , Chen Wen Bin , Lin Sheng , Zhang Rui
Published: March 2009

SiCw/3Y-ZrO2/A12O3 composites were prepared. The composite powders were prepared by a
precursor method. Samples were conventionally sintered at 1500°C and 1580°C for 2h in air. The density,
phases, microstructure, hardness of the SiCw/3Y-ZrO2/A12O3 composites were investigated. It was found
that the relative density of the samples decreased as the increasing content of SiCw. The optimum
mechanical properties may be obtained in the SiCw/3Y-ZrO2/A12O3 composites with 5 vol.% SiCw.
Preparation and Properties of SiC Fibers Containing Yttrium and Aluminum
Authors: Yang Da Xiang , Song Yong Cai
Published: March 2009

SiC fibers containing Y and Al were prepared by sintering the amorphous KD-Y fibers at
different temperatures from 1200 to 1800 °C. The tensile strength of fibers increases when the sintering
temperature increases from 1200 to 1400 °C due to the dispersion strengthening of β-SiC microcrystal
and decreases to the lowest point when being sintered at 1600 °C, then rose again with the further increase
of temperature to 1800 °C. The tensile strength reached to 2.15 GPa. The oxygen content of KD-Y fibers
determined the properties of the sintered SiC fibers and sintering process. Through chemical vapor curing
(CVC), the oxygen content was controlled below 7.0 wt% and the tensile strength of KD-Y fibers reached
to 3.08 GPa. Further-more, the sintering process of KD-Y fibers was discussed and the grain size of β-SiC
grew up with the heat treatment temperature.
Combustion Synthesis of β-Si3N4 and β-SiAlON with Elongated Prismatic Micro-Crystals by Adding SrCO3 and NH4F
Authors: Liu G.H. , Chen Ke Xin , Zhou He Ping , Li Jiang Tao , Zhong Ji Dong , Ferreira José Maria F.
Published: March 2009

β-Si3N4 and β-SiAlON powders were prepared by combustion synthesis with SrCO3 and NH4F
used as additives. The resultant β-Si3N4 and β-SiAlON powders consisted of elongated prismatic microcrystals.
By adding SrCO3, the anisotropic growth of β-Si3N4 and β-SiAlON crystals is improved and
their aspect ratios increase. The addition of NH4F enhanced nitridation reactions and reduced the residual
Si in combustion products. It was proposed that the elongated prismatic β-Si3N4 and β-SiAlON crystals
grew from liquid phase and the composition and property of this liquid was affected by the addition of
SrCO3.
Optimization of α-SiAlON Microstructure by Heat Treatment
Authors: Kurama S.
Published: March 2009

Nd-doped α-SiAlON starting composition (Nd0.33Si9.38Al2.62O1.62N14.38) was prepared by gas pressure sintering at 1825°C for 3 hrs. In order to explore the effect of post heat treatment on the developments of elongated α-SiAlON grains, sample was heat treated at 1800°C for 4-12 hrs. It was found that post heat treatments promoted formation of the elongated α-SiAlON grains. The controlling mechanism of grain growth was determined via plotting on a graph the growth in width/length versus time graphics using Image Analysis method. Different growth rates were found between the length and width direction of the α-SiAlON crystals, resulting in anisotropic grain growth in the microstructural development.
Effect of Yttrium(Y) Content in Al Target on the Thickness of CrAlTiN Film by Magnetron Sputtering
Authors: Liu Zhao Zheng , Liu Yao Hui , Jiang Bai Ling , Yu Si Rong
Published: March 2009

In this experiment UDP450 was used to prepare the CrAlTiN films with different Y
contents deposited on Si(100) substrates. The thickness and structure of CrAlTiN films were
characterized by scanning electron microscopy (SEM). The results show that the thickness of
CrAlTiN films increases with the increasing of Y contents in Al targets. Meanwhile, the structures
of these films are column structures with the least changes. XPS and EDS results indicate that Al
contents in the films also increased with the increasing of Y contents in Al targets. Voltages of Al
targets were changed with the variation of Y contents in Al targets when CrAlTiN layers were
formed. The current of Al targets was a constant during producing CrAlTiN layer. The original
voltages of Al targets during forming CrAlTiN layers increased greatly with the increase of Y
contents in Al targets. The results show that the collision probability between the neutral particles
and positive ions increased in the vacuum chamber. This indicates that the sputtering yield of Al
targets is increased at a higher voltage. Consequently, the growing speed of CrAlTiN film and the
sputtering yield of Al targets are all improved with the addition of Y element.
Effect of Low-Energy Ion Irradiation on Synthesis of Hard and Superhard Films
Authors: Li Zhu Guo , Miyake S. , Wu Yi Xiong
Published: March 2009

This article summarizes briefly our recent research on low-temperature synthesis of TiN,
TiN/Cu and TiN/Si films by using inductively coupled plasma assisted magnetron sputtering method.
It is shown that the incorporation of high-flux low-energy ion irradiation during deposition strongly
affects film growth, structure evolution, morphology and mechanical properties. A main attention is
devoted to the synthesis of superhard nanocomposite films at a low deposition temperature. In both
TiN/Cu and TiN/Si films the maximum hardness reaches a value higher than 40 GPa.
Comparative Study of 321 Stainless Steel and 321-Al Composite Coatings Deposited by Arc Spraying Process
Authors: Chen Yong Xiong , Xu Bin Shi , Liang Xiu Bing , Xu Yi
Published: March 2009

A new type of composite coating (321—Al coating) was prepared by using the 321
austenitic stainless steel wire feed stock as the anode and aluminum wire as the cathode in arc
spraying process. In order to compare with the new composite coating, the traditional 321 coating
with twin 321 stainless steel wires was fabricated. The microstructure and wear resistance of the
coatings were characterized by means of scanning electron microscopy (SEM), X-ray diffraction
(XRD), energy dispersion spectroscope (EDS) and MM-200 ring-block type sliding wear tester.
Results showed that, except for the aluminum phase addition in the 321—Al coating, no other extra
phases produce in comparing with the 321 coating. However, due to the additional aluminum, the
321—Al coating performs quite different microstructure characteristics and tribological behavior.
The oxygen content and microhardness of the 321—Al coating are lower than that of the 321
coating, but wear losses are pretty much under the oil lubricated sliding condition. The effect of the
microstructure on the wear behavior of the 321—Al coating was also discussed, which is mainly
relevant to the characteristic of “ductile aluminum and hard stainless steel composite phases
inter-depositing”.
Study of Hard Chromium Plating from Trivalent Chromium Electrolyte
Authors: Li Bao Song , Lin An
Published: March 2009

Hard chromium deposits were prepared from a trivalent chromium plating bath as an
alternative to conventional hexavalent chromium deposits. The influences of bath composition on the
trivalent chromium electrodeposition process and deposited coating properties were studied. The
effects of plating parameters such as current density, bath pH and plating time on structure and
morphology of deposited coatings were investigated. Results show that the hard chromium deposits
exhibited amorphous structure with thickness of 50-100μm and acceptable quality for functional
coatings. The hard chromium deposits exhibited better wear resistance as well as corrosion resistance
than that of hexavalent chromium deposits. The hardness of as-deposited chromium coatings is about
600-700HV. Heat treatment could improve the wear resistance and hardness of the hard chromium
deposits. The formation of polynuclear coordination compounds from hydroxyl complex ions at high
pH is the main disadvantageous factor for the sustained trivalent chromium plating process.
Preparation and Property of Electrodeposited Zn-Fe-SiO2 Composite Coating
Authors: Fan Yun Ying , Zhang Ying Jie , Dong Peng
Published: March 2009

Electrodeposited Zn and Zn-Fe alloy have been applied widely to protect steel from
corrosion, but the property of coating still needs to be improved. In this paper, Zn-Fe-SiO2 composite
coatings are electrodeposited from Zn-Fe alloy electrolyte containing SiO2 particles. Zinc based
coatings with Fe% >1%(mass) are deposited from sulfate bath, and coatings with Fe% <1%(mass) are
deposited from chloride bath. Particle content in the composite coating generally increases with
particle concentration under an adequate agitation and then tends to saturation. The optimum particle
content in the composite coating is 0.5%(mass). Corrosion resistance, porosity, hydrogen
embrittlement and surface morphology of Zn-Fe-SiO2 composite coatings have been tested and
compared with electrodeposited Zn and Zn-Fe alloy. The data implies that Zn-Fe-SiO2 composite
coating has the best corrosion resistance, lowest porosity, lowest hydrogen content and the finest
crystal. All the results show that Zn-Fe-SiO2 composite coating is satisfactory to be used as
anti-corrosion material for steel and has a great future in application.
On the Properties of Conductive Adhesive Filled with Electroless Silver Plated Flake Graphite
Authors: You Min , Zhang Lu Lu , Gong Zheng Peng , Liu Wen Jun , He Ai Ping
Published: March 2009

The properties of the conductive adhesive such as resistivity, shear strength and water
-absorb ratio of the adhesive filled with the filler of Ag-coated graphite from electroless silver plating
procedure were studied using the universal meter, the diagrams of scanning electron microscopy
(SEM) and the shear strength testing. The results from the experiment showed that the resistivity of
the Ag-coated flake graphite was relative lower when the addition was less than 50 % (wt) to that of
the conductive adhesives filled with pure flake graphite. The shear strength of the conductivity
adhesive filled with Ag-coated flake graphite was usually higher than that one filled with un-treated
graphite and the peak values occurred when the filler addition was equal to 30%.
Preparing an Environment-Benignly Rare-Earth Based Chemical Conversion Coatings on 6063 Aluminium Alloy
Authors: Chen Dong Chu , Wu Gui Xiang , Li Wen Fang , Gong Wen Hui , Liang Yi Qing
Published: March 2009

In order to develop an environment-benignly chemical conversion process to substitute the
toxic hexavalent chromium treatment on Al alloy surface, a new surface treatment technology based
on rare-earth element, which is to form chemical conversion coating on 6063 Al alloy was presented.
In this process, Ce(NO3)3 was adopted in the chrome-free preparing solution, and KMnO4 was used as
oxidant to accelerate the coating formation on 6063 Al alloy. Furthermore, an L16(43) orthogonal
experiment was carried out to examine the effect of Ce(NO3)3, KMnO4 and solution temperature on
the coating growth on 6063 Al alloy. Accelerants of SrCl2 and NH4VO3 were added to the preparing
solution to improve the coating performance. XRD, SEM and EDS were used to analyse the coating
surface structure, morphology and composition. It was found that a good anti-corrosion coating which
is mainly composed of the elements of Al, Ce, O, Mn, Mg could be formed in the optimal preparing
solution of 5g/L Ce(NO3)3 , 4g/L KMnO4, 1.4g/L SrCl2 at the temperature of 20°C.
Low-Temperature Plasma Surface Modification of Medical Grade Austenitic Stainless Steel to Combat Wear and Corrosion
Authors: Buhagiar Joseph P. , Dong Han Shan
Published: March 2009

The novel low temperature plasma alloying technique that simultaneously introduces both
nitrogen and carbon into the surface of austenitic stainless steel has been used in the past to create a
hybrid N-C S-Phase. This S-Phase layer boasts of high hardness and wear resistance without any
detriment to corrosion resistance. In this study, the afore mentioned hybrid N-C S-Phase was
successfully implemented in the surface of two medical grade austenitic stainless steels: ASTM F138
and F1586. At an optimum process temperature of 430°C a very hard, 20μm precipitate-free S-Phase
layer was created. Anodic Polarization tests in Ringer’s solution showed that the corrosion resistance
of this layer was similar to that of the untreated alloys. Both dry-wear and corrosion-wear (Ringer’s)
behaviour of the surface treated alloys showed an improvement of more than 350% and 40%
respectively when compared to the untreated material.
Stacking Faults in a High Nitrogen Face-Centered-Cubic Phase Formed on Nitrogen-Modified Austenitic Stainless Steel
Authors: Liang J. , Lei M.K.
Published: March 2009

Effects of stacking faults in a high nitrogen face-centered-cubic phase (γΝ) formed on
plasma source ion nitrided 1Cr18Ni9Ti (18-8 type) austenitic stainless steel on peak shift and peak
asymmetry of x-ray diffraction were investigated based on Warren’s theory and Wagner’s method,
respectively. The peak shift from peak position of the γΝ phase is ascribed to the deformation faults
density α, while the peak asymmetry of the γΝ phase is characterized by deviation of the center of
gravity of a peak from the peak maximum (Δ C.G.) due to the twin faults density β. The calculated
peak positions of x-ray diffraction patterns are consistent with that measured for plasma source ion
nitrided 1Cr18Ni9Ti stainless steel.
The Finite Element Simulation Research on Stress-Strain Field of Laser Cladding
Authors: Zhang Ping , Ma Lin , Yuan Jin Ping , Yin Xiao Nan , Cai Zhi Hai
Published: March 2009

The tensile plastic strains and the residual tensile stresses caused by heat input during the
laser cladding process are the main reasons for the cracking. In this paper, the laser cladding process
on a type 1045 steel plate with Ni60 powder feeding was investigated and simulated by finite element
method to analyze the temperature field and stress-strain field of the laser cladding process. In the
temperature field model, the main considerations were given to the heat source data and the thermal
boundary conditions. The interactions of laser, powders and base metal were mainly considered in the
application of the heat source data. The relationship between the heat convection coefficient of work
piece surface and the temperature variation was mainly considered in the application of thermal
boundary conditions. In the stress-strain field model, the main consideration was given to the
elastic-plastic characteristics of the materials, and the materials were assumed to be linear
strain-strengthened. Moreover, the thermal stresses could be solved through the temperature field and
were subsequently applied directly to the stress-strain field model as loads. Besides the temperature
variations, the stress variations and the strain variations of some critical points (including the crest
point of the cladded layer and intersection point of cladded layer and plate) were also obtained
through the finite calculation. The temperature variations show that the heating curve is
approximately a straight line while the cooling curve is like an arm of a hyperbola. The strain
variations show that the thermal strain has a variation trend similar to the temperature variations. The
elastic strain of each point is very low when compared to the plastic strain. The calculated results
show that the tensile plastic strain of the crest point on the coating is the greatest in the cladding
direction and the tensile stress in this direction of this point is great too. As a result, transverse crack
can be easily initiated at the crest of the coating. While the tensile plastic strain at the intersection
point of the base metal and coating is the greatest in the direction vertical to the plate thickness, the
stress at this point (in the same direction) is compressive. Therefore, the intersection points tend to
form a limited toe crack which can not grow.
Preparation of Ag Nanoparticles Colloid by Pulsed Laser Ablation in Distilled Water
Authors: Xu Bing , Song Ren Guo , Tang P.H. , Wang J. , Chai Guo Zhong , Zhang Y.Z. , Ye Z.Z.
Published: March 2009

The Ag nanoparticles colloid was prepared by pulsed laser ablation for different time in
10 ml distilled water without any surface active agent, and it was analysed by means of UV-visible
spectrophotometer and transmission electron microscopy (TEM). The results showed that the
ablation efficiency and absorbance increased fast and shift to higher energies with increasing
ablation time from 5 to 10 min, then increased slowly from 10 to 20 min, and increased fast again
from 20 to 25 min. The morphologies of most Ag nanoparticles were nearly spherical. The average
diameter and its distribution decreased from 5 to 7.5 min, then increased from 7.5 to 15 min, and
decreased from 15 to 25 min.
Surface Modification of CrN Coating by Plasma Oxidation Process
Authors: Ho Wei Yu , Chen Hui Chu , Chang Chi Lung , Wang Da Yung , Ho Woei Yun
Published: March 2009

In this study, the CrN coating was first deposited on tool steels by cathodic arc evaporation
technique and then this coating was subjected to oxygen glow discharge to activate the oxidation
process in order to form oxide layer on the surface of the CrN coating. The varied properties of CrN
coatings with or without oxidation treatment were studied in terms of hardness, adhesion,
microstructure and surface morphology by using XRD, AFM, Rockwell indentation,
Nano-indentation tests. The result turned out that the effect of the plasma oxidation process on the
hardness of CrN coating was improved due to the oxide layer on the surface.
Microstructure and Wear Response of Ni/SiC Laser Cladding Composite Coatings on a Carbon Steel
Authors: Lou Bai Yang , Xu Bing , Zhou Y.B. , Bai W.J. , Du H.L.
Published: March 2009

The high-energy laser melts the cladding materials which coagulate onto the surface of
the base materials. The laser cladding coatings are produced mainly in two methods: powder
feeding and prefabricating. The grain-strengthening composite coatings could be formed more
easily by prefabricating method than by powder feeding method. In this paper, Ni/SiC ceramic
composite coating on carbon steel (45 steel) was made by prefabricating method. The
microstructure and wear-resistance of Ni/SiC cladding coating on the 45 steel were studied using
scanning electronic microscope (SEM) and wear test. The results showed that the microstructure of
cladding coatings included bonding layer, thermo-affected layer and heat-affected layer after laser
cladding. The microstructure of cladding coating was mainly of dendrite and cell-like crystals. The
resultant multilayered coating had excellent adherence with the base steel. The addition of SiC
particles into cladding coatings significantly reinforced the microhardness of laser cladding coating.
Compared with Ni60A cladding coating, Ni60A/SiC cladding coating had high microhardness,
which was attributed to not only the dispersion intensification effect of the SiC particle, but also by
the new complicated phases. During laser cladding process, SiC particles may decompose and
dissolve into the coating and result in solid solution strengthening effect which increases the
microhardness of the composite coatings. The base material and Ni-based laser cladding coatings
with and without SiC were tested to assess the wear-resistance property. The test results
demonstrated that the laser cladding coatings had better wear resistance than the base material.
Furthermore, the laser cladding coating with SiC particles had higher wear-resistance than the
coating without SiC.
A Numerical Simulation Studying for Plasma Expansion in Laser Ablation Processing
Authors: Tan Xin Yu , Wang Zhong Long , Feng Mao , Zhou Yine
Published: March 2009

A numerical simulation is proposed to study the dynamics expansion characteristics
during the material irradiated by a high-intensity laser beam.The ionization effect and the local mass
and momentum conservations for plasma expansion are considered in this model. As an example of
carbon target, the plasma flow dynamics into a vacuum, like ionization degree, plasma number
density and space pressure are studied in detail. The results show the plasma temperature strongly
affects the ionization fraction and the ionization effect evidently influences the plasma dynamic
expansion behavior. The space pressure of plasma decreases along with the plasma expansion.
The Application of Ultrasonic Phase Spectrum of the Reflection Coefficient on Nondestructive Characterizing the Plasma Sprayed Coatings Irradiated by HIPIB
Authors: Zhao Y. , Lin Li , Li X.M. , Lei M.K.
Published: March 2009

Ultrasonic phase spectrum of reflection coefficient has been used to nondestructively
characterize the density, porosity, and microcracks of plasma sprayed Cr2O3 coatings irradiated by
high-intensity pulsed ion beam (HIPIB). The ultrasonic measurement was investigated using
immersion focusing pulse echo method with a 25 MHz transducer and the phase spectrum of
reflection coefficient has been experimentally obtained. The relationship among velocity, density,
attenuation coefficient and the phase spectrum was analyzed based on an acoustic transmission model
in a multi-layered structure. The velocity relates to the harmonic frequency of the phase spectrum, and
the density and attenuation coefficient play roles on the amplitude of the maximum and the shape of
the spectrum. The effects of the three parameters (velocity, density and attenuation coefficient) on the
amplitude of the maximum of the phase are similar. Some critical value exists which change the
relationship between the individual parameter and the maximum of the phase spectrum. When one of
the three parameters exceeds the corresponded critical value, the amplitude of the maximum
decreases in the form of exp( ) n y = A Bx . For the as-sprayed and irradiated coatings with the thickness of
50 0m, the velocity calculated from the phase spectrum is 2522 and 2772 m/s, harmonic frequency
corresponding to 12.61 and 13.86 MHz, respectively. These ultrasonic determinations demonstrated
that the coating becomes more densified after irradiation by HIPIB, in agreement with SEM
observations. Ultrasonic phase spectrum itself is a good indicator to reveal differences between
density and microstructures of coating prepared with various conditions as well as to follow their
evolution after HIPIB irradiation.
Preparation and Characterization of Nickel-Based Composites Coatings Reinforced by TiB2+WC on Stainless Steel by Laser Cladding
Authors: Li Jun , Li Wen Ge , Zhang Guang Jun
Published: March 2009

The preparation and characterization of a nickel-based composite coating reinforced by
TiB2 particles produced in situ and WC particles on stainless steel by laser cladding have been
investigated. The experiment results show that the coating obtained at suitable parameters
epitaxially grows from the substrate. The coating is mainly composed of γ-Ni dendrite and
dispersed TiB2 and WC particles. In the upper part of the coating, the white phase dispersed in the
coatings is mainly fine batt-shaped TiB2 particles. In the middle and bottom parts of the coating, the
white phase is mainly composed of comparatively coarse equiaxial WC particles, only an small
amount of fine TiB2 particles are present. The different distribution of TiB2 and WC should be
attributed to the density difference of TiB2, WC and Ni-based alloys and the comparatively slow
scanning rate. No cracks were observed throughout the whole coating, especially in the interface,
after the coating was deal with by the thermal shock experiment, which shows that the coating
processes a good metallurgical bond with the substrate and the high cracking resistance.
Research on Friction and Wear Performance of Brake Disc Pair Materials for New Type of Drilling Rig
Authors: Wang Xin Hua , Zhang Si Wei , Wang De Guo
Published: March 2009

Tribological performance of new brake pair is studied at different temperatures, load and
speed by variable temperature friction and wear test. The research indicates that brake pair has
better frictional characteristics at variable temperature as well as heat-fade resistance performance at
high temperatures. Wear rate of brake block and brake disc increases with friction temperature
rising, however wear-resisting performance of brake disc is comparatively stable. Load has less
influence on frictional coefficient of brake pair. Wear rate of brake disc and brake block increases
with load increasing, but brake block has comparatively stable wear-resisting performance.
Frictional coefficient of brake pair increases and tends to stabilize gradually along with sliding
speed increasing, and speed has less influence on wear rate of brake block and brake disc. Initial
heat-fading occurs in brake block material along with frictional temperature rising, secondary
solidification may happen when frictional temperature reaches a certain value. When temperature
rises much higher, brake block begins to soften and plastic flow intensifies, in addition thermal
decomposition occurs in organic substance and wear-resisting performance becomes poorer.
Build-up welding material has strong age-hardening effect and stable thermal structure, which
leaves surface hardness and structure performance of brake disc unchanged at high temperatures.
Corrosion Behavior of AZ31 Magnesium Alloy with Microarc Oxidation Film Irradiated by High-Intensity Pulsed Ion Beam
Authors: Han X.G. , Li P. , Zhu X.P. , Lei M.K.
Published: March 2009

The microarc oxidation (MAO) films on AZ31 magnesium alloy were modified by
high-intensity pulsed ion beam (HIPIB) at an ion current density of 200 A/cm2 with 1-5 shots. The
modified MAO films presented a corrosion resistance superior to that of the original films.
Scanning electron microscopy (SEM) observation revealed that a sealing layer was formed on the
MAO films by HIPIB irradiation. The corrosion behaviors of the MAO films in 3.5 % NaCl
solution were characterized by using electrochemical impedance spectroscopy (EIS). The noticeable
improvement in the corrosion resistance of MAO films is attributed to the blocking effect of the
sealing layer that hinders the process of electrolyte penetrating the MAO films to the magnesium
alloy.
Structure and Properties Investigation about a Copper-Base SHS Welding Material
Authors: Hu J.Z. , Ma Shi Ning , Chen X.R.
Published: March 2009

A new Copper-base SHS welding material was developed to meet the demand of the
welding mend about metal parts in field. The structure and properties of the welding line were
studied and the results indicated that the welding was belong to fusion welding, the fusion area
between the parent metal and the welding line was clear, the tensile strength of the welding line
over 200MPa, the bend strength close to 600MPa and the surface hardness close to HRB130. All
these indicated that this copper-base material could be used in emergency maintenance welding
about metal parts.
The Study of the Boundary Lubrication Mechanism of BN-C-Silicone Oil Composite Colloid at High Temperature
Authors: Guo Hong , Liu Zuo Min
Published: March 2009

Nano-scale BN-C-silicone oil composite colloid was prepared in a planetary ball mill by
using wet grinding techniques. Frictional experiments with GCr15 and 35CrMo as frictional pairs
were then conducted under a wide range of temperature (from ambient temperature to 300°C) on a
pin-plate friction and wear tester. Results show that lubricating properties of the colloid were
improved significantly. In particular, the frictional coefficient of the colloid is lower than that of the
pure silicone oil at both ambient temperature and high temperature. For example, at ambient
temperature, the frictional coefficients ( f ) of the BN-C-silicone oil composite colloid and pure
silicone oil are about 0.05 and 0.18, respectively; while at 300°C, the f value of the BN-C-silicone
oil composite colloid and pure silicone oil are about 0.13 and 0.36, respectively. The characteristic of
the worn surface film was also investigated by using SEM. SEM images show that on the worn
surface, the concave zone is filled with some nano BN-C particles; while the rest of the particles are
dispersed in the surface film. Therefore, BN-C particles may repair the worn surface, which tend to
improve the boundary lubricity of the silicone oil. Finally, based on the model proposed by
T.A.Stolarski, the rupture ratio of the lubricating film was discussed to address why BN-C-silicone oil
composite colloid has relatively lower frictional coefficient even at high temperature.