bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation Uniform of TiO2 Microporous Ceramic Membrane Supported by Al2O3
Authors: Zhang Xin , Li Gai Ye , Zhang Jian Feng
Published: July 2016

In this study, a TiO2 ceramic membrane was coated on the porous Al2O3 ceramic support by a dip-coating method using a self-designed apparatus. A flat, low-porous and uniform membrane was obtained based on the optimized ingredient and fluidity of TiO2 suspension. The effects of thickening agent content on the stability of the membrane casting solution and the microstructure of the membrane were investigated.
Phase Evolution and Surface Morphology of Niobate Hydrate Template Nanoparticles Synthesized by Hydrothermal Method
Authors: Wang Yuan Yu , Xu Nuo Xin , Liu Jin Zhuang , Zhang Qi Long , Yang Hui
Published: July 2016

In this work, an alternative approach to synthesize (K,Na)NbO3 (KNN) particles is investigated. KNN hydrate particles were prepared by hydrothermal method in a mixed alkaline solution with different KOH/(KOH+NaOH) ratios , and phase structure as well as surface morphology of these niobate hydrate particles were systematically studied. For the reaction rate of Na+ is faster than K+, a mixed alkaline solution with K+/Na+ changing from 4/1 to 5/1was required as a starting solution so a to obtain KNN hydrate particles with K/Na=1. Besides, the results show that particle size of KNN hydrate particles synthesized in different starting solution is dependent on K+/Na+ of the starting solution, and grain size of as-sintered KNN ceramics through hydrothermal method decreases sharply.
Hydrothermal Synthesis of Bi4Ti3O12/TiO2 Composite
Authors: Zhao Wei , Liu Nian Qi , Wang Hong Xing , Zhang Yu Bo , Zhang Shi Meng , Gao Ke Xin , Chen Xu , Fan Zhi Yun
Published: July 2016

A hydrothermal processing technology was employed to synthesize Bi4Ti3O12/TiO2 composite by using TiO2 and Bi(NO3)3 as reactor precursors, and KOH as mineralizer. The microstructure and composition of the as-synthesized samples were characterized by X-ray diffraction (XRD), scan electron microscopy (SEM), and the photocatalytic activity was studied. The results showed that Bi/Ti molar ratio, mass of the KOH and the hydrothermal parameters play important roles on the morphology and activities of the photocatalyst. We could obtain composites with good morphology and better performance with 200 °C hydrothermal treatment for 12 h, 0.01 mol/L of KOH, and 1:2 of mole ratio of Bi/Ti, as well as using good crystalline TiO2 as the raw material. The as-prepared powder has a diameter of about 800nm, and the decolorized rate of methylene blue could reach 95 % after the UV-irradiation for 5 h.
Study on the Pore Structure of Forsterite Insulating Material
Authors: Liu Jian Peng , Zhang Xiao Jun , Zhu Hong Xi , Deng Cheng Ji
Published: July 2016

Forsterite insulating materials were prepared by molten salt method using forsterite powder, pulp waste, NaCl and Na2CO3 as raw material. The pore size distribution and pore structural parameters of the sample were studied by nitrogen adsorption-desorption method. The fractal dimension of pore was obtained based on FHH (Frenkel-Halsey-Hill) equation. The results showed that adsorption-desorption isotherm of the sample was identified as type II due to the long-narrow pore with narrow openings. The pore size and fractal dimension decreased with the temperature increased. The maximum pore size was about 2 nm in the sample heated at 1100°C in the condition of different content of molten salt. And optimal thermal insulation performance of the sample were obtained in the sample contained 30 wt% Na2CO3 and heat treated at 1100°C.
Bacterial Cellulose Aerogels Skeleton Strengthened by Regenerated Cellulose
Authors: Fu Rui , Sai Hua Zheng , Xing Li , Xiang Jun Hui , Li Zhen You , Zhang Ting , Zhang Fu Shi
Published: July 2016

Soft skeleton of bacterial cellulose aerogels (BCAs) was strengthened effectively by conformal coverage of regenerated cellulose to make sure the BCAs sustain more compression. After freeze drying, compression modulus of the strengthened sample is significantly higher than that of the BCAs, which endows the former more extensive applications. The regenerated cellulose solution was prepared by gelation of cellulose from aqueous alkali hydroxide/urea solution. Then the bacterial cellulose wet gels bulks were immersed in the regenerated cellulose solution with different contents to discuss the enhanced effect of the BCAs skeleton. The morphology of the enhanced BCAs was observed by scanning electron micrograph (SEM).The porous structure of the enhanced BCAs was investigated by Brunauer-Emmett-Teller (BET) instrument. The stress−strain curves of the enhanced BCAs were measured. The XRD pattern of the strengthened sample was also carried out. The results indicated that regenerated cellulose forms thin layers which conformally covered bacterial cellulose skeleton fibers and that had little effect on microstructure and crystal form of the bulk cellulose aerogels.
Effect of Sintering Pressure on Mechanical Properties of BN-Si3N4 Ceramic Composites Prepared by Spark Plasma Sintering
Authors: An Jia Xin , Xue Wen Dong , Zhai Feng Rui , Xu Ruo Meng , Sun Jia Lin
Published: July 2016

BN-Si3N4 composite ceramic wave-transparent materials with excellent mechanical properties were prepared by spark plasma sintering (SPS) using h-BN and α-Si3N4 powders as raw materials, Al2O3 and Y2O3 as sintering aids. The influence of sintering pressure on density and mechanical properties of BN-Si3N4 composite ceramics were studied. The phases were observed by X-ray diffraction (XRD), and the microstructures were identified by scanning electron microscopy (SEM). The results showed that with the sintering pressure increases, the relative density, bending strength and fracture toughness of the composite ceramics were significantly increased, and the porosity decreased rapidly. The effects of pressure on the properties of the composite ceramics was not significant at >40MPa, so 40MPa is optimal for the composite ceramics to gain good overall performance, i.e. the relative density was 89.1%, the porosity was 2.3%, the bending strength reached 215.4 MPa, and the fracture toughness was 3.1/MPa·m1/2.
Effect of Buried Powder Sintering on the Electrical and Piezoelectric Properties of CuO-Modified (Li,K,Na)(Nb,Sb)O3 Lead-Free Piezoceramics
Authors: Li Lin Ling , Zhen Yu Hua
Published: July 2016

A strong desire for environmental protection and human health care urgently requires us to find an environmental friendly type of piezoelectric material to replace the lead ones. In this study, (LixK0.5-xNa0.5)(Nb0.97Sb0.03)O3-1mol%CuO (x = 0, 0.05, 0.1 ,0.2 ,0.5, abbreviated as CuO-LxKNNS) lead-free piezoelectric ceramics have been fabricated by a conventional solid-state reaction route. We focused on the comparison of buried powder sintering with exposed sintering. The effect of buried powder sintering method on density, structure and dielectric, piezoelectric properties of CuO-LxKNNS ceramics has been investigated. It was found that the density increased greatly when the buried powder sintering method was used, which was effective in inhibiting the volatilization of alkali metal oxides compared with exposed sintering method. Piezoelectric and dielectric properties showed a similar tendency with the density. These ceramics showed an obvious phase transition with increasing the Li content. CuO-LxKNNS ceramics showed orthorhombic symmetry when x= 0, but turned to be tetragonal symmetry when x ≥ 0.05. The optimal composition of CuO-LxKNNS with buried powder sintering method was x = 0.05 sintered at 1020 °C, for which the maximum value of the piezoelectric constant (d33) was 180pC/N, the density (ρ) was 4.40g/cm3, the room temperature relative dielectric constant (εr) was 270 and the dielectric loss (tanδ) was 0.07.
Preparation of High-Purity Magnesium Aluminate Spinel Powder by Thermal Decomposition Method
Authors: Wu Xiao Juan , Li Jun Shou , Tang Xiang Jun , Wang Ming Yuan , Li Su
Published: July 2016

A precursor was obtained after dissolution, drying and cooling using MgSO4·7H2O and NH4Al (SO4)2·12H2O as raw materials. Then the high-purity magnesium aluminate (MgAl2O4) spinel powder was synthesized via the thermal decomposition process of the precursor calcined at different temperatures. The phase, morphology and particle size of the powder obtained at different calcining temperatures were characterized by X-ray diffraction, scanning electron microscopy and laser particle size analyzer. And also the purity of the powder was tested by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results show that the powder exhibits better crystalline shape and bigger crystalline size with the calcining temperature increasing. The calculated grain size is below 30 nm according to Scherrer formula. The particle size of the powder is below 35μm, the particle size distribution is relatively wide and some particles reunite to be bigger ones with the calcining temperature rising. The powder appears to be plate-shaped and the morphology of the grain is irregular particle. The purity of the powder is relatively high. Especially, the purity of the powder obtained at 1150 °C is 98.88%.
Preparation of Amorphous SiOC Ceramic Powders through Precursor Polymer Pyrolysis
Authors: Ma Ming Bo , Wang Hong Jie , Wen Jiang Bo , Niu Min , Fan Xing Yu , Su Lei
Published: July 2016

SiOC ceramic as anode material for lithium ion batteries has received extensive attention recently. In this work, polycarbosilane and polymethylhydrosiloxane were used as precursor polymers through a curing, pyrolysis and ball-milling progress to synthesize three kinds of ceramic powders with different components noted as SCO1, SCO2 and SCO3, respectively. The pyrolysis process of precursor polymers were investigated by the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). And the effect of ball milling progress on the particle size of SiOC ceramic powders was researched. The microstructure of ceramic powders was investigated by scanning electron microscopy (SEM), phase and element composition was analyzed by X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS), and the tap density of ceramic powders was measured. Results show that when the curing temperature was 190 °C and the pyrolysis temperature was 900 oC , the ceramic powders with the particle size between 70 nm-2 μm can be obtained through the ball-milling method at the milling speed of 350 r∙min-1 and ball-milling time of 25 h. The SiOC ceramic powders pyrolyzed at 900°C were amorphous, containing Si, C and O elements. The addition of polymethylhydrosiloxane can adjust contents of C and O in SiOC ceramics. The tap density of the powders was increased from 0.65g∙cm-3 to 0.76 g∙cm-3 with the addition of polymethylhydrosiloxane.
Influences of Preparation Parameters of Catalyst Support on the SCR Denitration Activity of Mn-Ce/TiO2
Authors: Wu Yan Xia , Liang Hai Long , Chen Xin , Tang Jie , Chen Yu Feng , Zhao Chun Lin
Published: July 2016

The catalytic performance of NO removal was studied over Mn-Ce/TiO2 catalysts prepared by different preparation parameters, such as preparation method, Ce/(Mn+Ce) molar ratio and calcination temperature. It was found that samples prepared by co-precipitation method, which had the largest surface area and highly dispersed active component particles, showed the best denitrification activity. The highest NO conversion of 95% is achieved at the Ce/(Mn+Ce) molar ratio of 15% which is much higher than that of the pure manganese constituent. The increase of calcining temperature favored the crystallization of active components, leading to the decline of catalytic activity.
Effects of Eu and Ca Co-Substitution for the Improvement of Multiferroic Properties of BiFeO3
Authors: Xu Xin , Yao Qi Fu , Peng Sheng , Fang Long Kai , Mao Wei Wei , Yang Jian Ping , Li Xing Ao
Published: July 2016

Pure BiFeO3 (BFO), Ca-doped and Eu/Ca-codoped BFO nanoparticles were prepared by using a sol–gel method. The effects of Eu/Ca-codoped on the structural, magnetic and ferroelectric properties of the samples were studied. The X-ray diffraction (XRD) analysis reveals a structure transition in the codoped samples. Co-doped samples were obtained with the best ferromagnetic properties, with the largest remaining magnetization Mr = 0.20 emμ/g. The structure transition may be the main cause for the origin of improved magnetic properties, which destroys the space modulated spin structure of BFO and releases the locked magnetic. In addition, the doping of Eu into BFO can reduce the leakage current and enhance the ferroelectric properties.
Synthesis and Up-Conversion Luminescent Properties of Na(Y1.5Na0.5)F6 Hexagonal Prism
Authors: Zhong Cui Ping , Zhang Jie Jun , Duo Shu Wang
Published: July 2016

Na (Y1.5Na0.5)F6 microparticks were prepared by hydrothermal method. EDTA as the chelating agent. The samples were characterized by X-ray diffraction, scanning electron microscopy and fluorescence spectrometer. The X-ray diffraction indicates that the crystal shows a hexagon phase structure. Under the excitation of 980nm laser, the Na (Y1.5Na0.5)F6 exhibited strong up-conversion light: 4F9/2→4I15/2(red), 4H11/2/4S3/2→4I15/2(green) and 4G11/2→2H9/2 (near-ultraviolet).
Preparation of Zirconium Diboride Nanopowders Using Different Zirconium Sources via Sol-Gel Method
Authors: Qin Xi Xi , Zhao Xiao Dong , Ji Hui Ming , Zhao Zhe
Published: July 2016

Zirconium diboride nanopowders were synthesized by sol–gel method using different zirconium sources of zirconium carbonate and zirconium nitrate based on different gelling processing. Both of zirconium source can be applied in the synthesis of good performance ZrB2 powders while the in-suit sol-gel using zirconium carbonate tend to form the spherical ZrB2 powders about 50nm and the traditional sol-gel using zirconium nitrate prefer to form worm ZrB2 powders about 200nm. The influences of B/Zr molar ration of zirconium carbonate and zirconium nitrate of sol-gel method on the phase constitution was investigated. And the gel mechanism was discussed to explain the different phase constitution, morphology of final products.
Preparation and Performance of Monazite Coating on Woven Alumina Ceramic Cloths
Authors: Liang Yan Yuan , Li Guang Ya
Published: July 2016

Monazite (LaPO4) coatings were deposited on woven cloths of alumina fibers by heterogeneous nucleation and growth using solution precursors. Coatings were characterized by scanning electron microscopy, and X-Ray diffraction; thermogravimetric analysis was performed on LaPO4 precursors. The results show that the optimum ration of La:citrate:P is 1:2:5 in the LaPO4 precursor solution. Coating thickness distributions were measured and analyzed. Uniform monazite coatings (210-250nm) were obtained after depositing in the precursor solution, drying and heating at 900°C for 5 min for 6 recycles. Al2O3f/ Al2O3 composite with the LaPO4coating as the CMC interface revealed goodmechanical strength and the fracture mode is ductile fracture. The tensile toughness is 142.2 MPa, the bending toughness is 288.6MPa and the fracture toughness12.2 MPa•m1/2.
The Effect of Aging Temperature and pH Value of Aging Solution on the Microstructure of ZrO2-SiO2 Aerogels
Authors: Qiao Ying Chen , Li Xiao Lei , He Jian , Ji Hui Ming , Shen Zhu Rui , Hu Zhi Peng
Published: July 2016

ZrO2-SiO2 gels were prepared by prehydrolysis method with sol-gel process. Then,the wet gels were aged at different temperatures (60,110,170 °C) in ethanol or alkaline solution (pH=8). Finally, the monolithic ZrO2-SiO2 aerogels were obtained by supercritical fluid drying. N2 adsorption-desorption, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the microstructure of aerogels. The aim of this research is to study the effect of aging temperature and pH value of aging solution on the microstructure of ZrO2-SiO2 aerogels. The results show that the specific surface area and pore volume of ZrO2-SiO2 aerogels aging in alkaline solution (pH=8) is lower than that of aging in the ethanol. And there is a shift of the pore size distribution towards larger values. This is because the cross-linking reaction in alkaline solution enlarges the particle size. As the aging temperature increases, the specific surface area and pore volume decrease and the particle size distribution of ZrO2-SiO2 aerogels is more uniform.
Thermal Insulation Property of Nanostructured Alumina Coated Zirconia Thermal Barrier Coating
Authors: Yi Zhong Zhou , Shan Ke , Zhai Feng Rui , Sun Hong Yan , Xie Zhi Peng
Published: July 2016

nanostructured Al2O3 coated ZrO2-Y2O3 thermal barrier coatings were prepared by plasma spraying method using nanostructured alumina coated 8mol%Y2O3 stabilized ZrO2 powder as starting material and the thermal insulation property was investigated as a function of the thickness of the coating. The results indicate that the structure and property of thermal barrier coating using nanoAl2O3 coated ZrO2-Y2O3 powder was superior to that of using single zirconia powder. The thermal insulation property of the thermal barrier coating increased with thickness of the coating increasing, and the advantage is more obvious with temperature increasing.
Mechanically Strong and Hierarchical Porous Silica Ceramics via Gelcasting-Lyophilization
Authors: Wan Wei , Yang Jian , Feng Yong Bao , Qiu Tai
Published: July 2016

Highly porous silica ceramics were prepared by in-situ gelation of an aqueous suspension with well dispersed silica particles and N’N-dimethylacrylamide (DMAA) monomer, followed by lyophilization and pressureless sintering. The gelcasting process was imparted by polymerization of DMAA. The silica raw materials used in this experiment are the dusts collected from the exhaust fumes of silicon industry. The as-obtained porous silica ceramics had three-dimensional and hierarchical pore structure and the porosity ranged from 75 to 88 % as the sintering temperature varied from 850 to 1050 °C. In addition, the porous silica ceramics appeared to have strong mechanical strength. Compressive strength of the porous silica ceramics was as high as 3.2 MPa even when the porosity was nearly 80%. The gelcasting-lyophilization method was proved to be a novel and promising route for the preparation of highly porous and mechanically strong materials.
Preparation and Properties of Acupuncture Quartz Fiber Reinforced Quartz-Based Composites
Authors: Wang Ying Ying , Wei Qi Hong , Wang Hong Sheng , Shao Chang Tao , Cheng Hong Hao , Zhang Qing Li
Published: July 2016

Quartz-based composites reinforced by acupuncture quartz fibers were prepared by liquid phase infiltration-in situ solidification process. Effects of different molding processes on the density, micro-structure, phase structure and mechanics properties of the composites were studied. The experimental results show that the composite materials prepared by the silica slurry as matrix and 10% silica sol as the interface layer have better performance: the density increased from 0.74g/cm3 to 1.58g/cm3; the tensile strength, flexural strength and compressive strength reached 32.2MPa, 72.6MPa and 116MPa respectively; it is worth noting that the micro-structure of the material is uniform and compact, and the fracture mode of the material is ductile fracture with the pull out of the fiber.
Preparation of Zirconium Diboride Powder by Carbon Thermal Reduction Method
Authors: Ma Li , Yu Jin Cheng , Zhang Yu Jun , Gong Hong Yu , Li Qi Song , Guo Xue
Published: July 2016

Zirconium diboride (ZrB2) powders with no impurities were prepared using zirconium oxide (ZrO2), boron carbide (B4C) and carbon black as raw material by carbon thermal reduction. The phase composition of ZrB2 powders was characterized by X-ray diffraction (XRD) and the micro-morphology was observed by scanning electron microscope (SEM). The effects of B4C content, calcination temperature and holding time were studied on the formation of ZrB2 powders. The results indicated that ZrB2 powders could be successfully synthesized while holding for 1.5 h at 1600 °C in Ar atmosphere. When the content of B4C was 17.7 wt% , there existed the crystal phase of ZrB2 only. The impurities could be easily led in with the increase of content of B4C. ZrB2 powders with the size from 1-5 μm could be obtained eventually and the particle size grew obviously with increase of the holding time.
Influence of Sintering Aids on the Sintering and Conductivity Properties of Si3N4 Composites
Authors: Jiang Yong , Wu Lan Er , Hai Wan Xiu
Published: July 2016

Silicon nitride (Si3N4) is one of the most important engineering materials. The developing trend of Si3N4 ceramic should be its composite with reinforce phase. However, due to its low self-diffusion coefficient at high temperature, the Si3N4 is very hard to be densified without sintering aids. In the present work, the Y2O3 and light rare-earth oxides of La series (La2O3, CeO2, Pr2O3, Sm2O3) and AlN, Al2O3, MgO, CaCO3 were chosen to be sintering aids. Their effect on the sintering of Si3N4 composite was studied. The results showed that the Y2O3 was the best sintering aid in all members, and the Y2O3-La2O3-AlN ternary composition was the best formula.
Preparation of Sialon/Si3N4-SiC Composite Refractories Using Kyanite Tailings
Authors: Fang Ming Hao , Huang Zhao Hui , Liu Yan Gai , Min Xin , Zhang Li Na
Published: July 2016

Sialon-SiC composite powders were synthesized from kyanite tailings through the carbothermal reduction nitridation (CRN) technique. Using Sialon-SiC composites to substitute Si3N4 composites via the CRN technique synthesize Sialon/Si3N4-SiC composite refractories. The phase composition, cross section morphology, and the substituent amount of Sialon-SiC composites impact on refractories mechanical properties were investigated, respectively. The optimized synthesis temperature for the CRN reaction was found to be 1550 °C for 4 h with the excess carbon 20%. The substituent amount of Sialon-SiC was 25%, the mechanical properties of Sialon/Si3N4-SiC composite refractories reached optimal performance, which bending strength value was 41.8 MPa and compression strength value was 61.6 MPa.
Wetting and Interfacial Behavior of Molten Al on Mo-Ni(Co)-Si Coated SiC Ceramic
Authors: Zhao San Tuan , Zhang Xiang Zhao , Liu Gui Wu , Xia Hong Yan , Shi Zhong Qi , Qiao Guan Jun
Published: July 2016

The Mo-Ni (Co)-Si metallizing coatings on the SiC ceramic substrate were prepared by vacuum cladding process. The wetting and spreading of molten Al on coated SiC ceramic substrates at 900 oC were investigated by the sessile drop technique, and the interfacial behavior of the Al/coated SiC wetting couples was analyzed. The experimental results showed that the final contact angle of Al/M20NiSi coated SiC was close to 0o. With the increase of Mo content in the Mo-Ni-Si coating, the shape of the sessile drop became very irregular due to the strong interactions between the Al drop and the coating, so it was unable to precisely characterize the contact angles of Al/Mo30NiSi and Al/Mo40NiSi systems. The final contact angle of Al/Mo10CoSi coated SiC system was also close to 0o, however, the final contact angle of Al/Mo20CoSi coated SiC system climbed to ~42o with the Mo content increasing from 10 at.% to 20 at.%. The significant increase of contact angle may be caused by the accumulation of Mo near the triple line which can impede the spreading of Al drop.
High Pressure and High Temperature Sintered PcBN Using Al, B4C and C as Sintering Additive
Authors: Ma Yao , Li Jian , Wang Hai Long , Zhang Rui
Published: July 2016

Polycrystalline cubic boron nitride (PcBN) composites were sintered by high pressure and high temperature sintering (HPHT) at 1450 °C for 3 min under a pressure of 5.0 GPa. Aluminium,boron carbide and carbon in the starting mixture reacts with cubic boron nitride (cBN) to form Al3BC3 and AlN bonding among cBN grains during sintering. X-ray diffraction (XRD) and Scanning electron microscope (SEM) were used to analyze phases and micro-structure of the sintered samples. The dense structure of super hard cBN grains bonded together with Al3BC3 and AlN offers superior hardness and high strength. The Vickers hardness of PcBN composites was 45±5 GPa, and the strength of PcBN composites was 345±15 MPa.
Nitridation Isothermal Kinetics of In Situ β-Sialon Bonded Al2O3-C Refractories
Authors: Yang Xue Qing , Peng Nai , Deng Cheng Ji
Published: July 2016

The kinetics of in-situ β- Sialon bonded Al2O3-C (SAC) refractories were investigated by TGA techniques via isothermal nitridation experiments at different temperatures. The result show that the nitridation process of in-situ β-Sialon bonded Al2O3-C refractories can be divided into two stages: the nitridation reaction rate controlling stage in the first 10 min, and the apparent activation energy of nitridation reaction is 370 kJ/mol ; then the reaction is controlled by both chemical reaction and diffusion rate in the following 110 min, the apparent activation energy of nitridation reaction is 410 kJ/mol.
Effects of Al Content on the Phase Constitution of Aluminum-Periclase Composites at 1600°C in N2
Authors: Yue Dan Dan , Li Yong , Tong Shang Hao , Ma Jia Jia , Hong Yang
Published: July 2016

Al-Al2O3-MgO specimen was made with fused magnesia as aggregate, tabular alumina, fused magnesia and aluminum as co-matrix. It is sintered at 1600 °C under N2. Aluminum powder contents is 0%, 4%, 6%, 10% respectively. The result shows: the sample has formed new phase of AlN, AlON, MgAlON. When aluminum powder contents is 4% AlN and AlON begin to form, and aluminum powder is 6% AlN and AlON form obviously, and MgAlON is formed. Besides the amount of MgAlON is increasing with the aluminum content adding. Aluminum-adding is good solution to decrease the synthesis temperature of AlON, MgAlON.
Influence of Voltage on the Biological Performance of Micro-Arc Oxide Films Based on TC4 Titanium Alloy
Authors: Yan Ji Kang , Teng Yuan , Ni Er Xin , Wu Yun Feng , Sun Yan Hua , Fang Shu Ming , Shi Zhe , Yang Gang
Published: July 2016

The porous ceramic biologic films were prepared on the surface of Ti6Al4V (TC4) with micro-arc oxidation technology (MAO). The phase composition, microstructure and valence state of micro-arc oxide films were studied. The biological properties of the ceramic film were comprehensive evaluated through animal experiments. Results show that with increasing of the micro-arc oxidation voltage, the better biocompatible hydroxyapatite appears on the surface of titanium alloy (TC4). The high voltage promotes the surface pore size enlarge. The porous ceramic surface makes bone tissue early grow up. Pathological sections of bone tissue 24 w animal experiments indicates that the implants can form good biological combination with bone, no rejection and the higher the micro-arc oxidation voltage, the more new bone cells.
Effect of Thermal Oxidation Temperature on the Properties of Micro-Arc Oxidation Ceramic Coating on TC4 Alloy
Authors: Ni Er Xin , Yan Ji Kang , Wu Yun Feng , Teng Yuan , Duan Zhi Cao , Jiang Gui Min , Sun Yan Hua , Yang Gang
Published: July 2016

The effect of thermal oxidation temperature on the properties of MAO ceramic coating was investigated, The phase composition and surface morphology of composite oxidation coating were analyzed by XRD and SEM. The micro-hardness of composite oxidation coating were tested by micro hardness tester. The results shown that the composite oxidation coating consists of rutile, anatase Ti and HA. With the thermal oxidation temperature increasing, the micro-hardness of composite oxidation coatings were improved, but when the thermal oxidation temperature rose from 600 °C to 700 °C, the micro-hardness of coating dropped from 575 HV to 505 HV. With the thermal oxidation temperature increasing, the numbers of micro-porous on coating surface was decreased , and the composite oxidation coating became more density.
Effects of Si3N4 Additions on Creep Resistance of Al-Al2O3 Composites
Authors: Shi Hao Ning , Li Yong , Li Chuan Jing , Qin Hai Xia , Sun Jia Lin
Published: July 2016

Si3N4 (0 and 6 mass%) were added to Al-Al2O3 composite respectively, with phenolic resin as binder, to make Al-Si3N4-Al2O3 unfired composites, which were dried at 200°C for 24h.The creep properties of composites were tested researched under 0.2MPa×50h at 1300°C. The results indicated that the samples put up the features of steady-state creep stage from 25h to 50h; Al4O4C appeared in the corundum matrix with the addition of Al,which improve its creep resistance; when Al and Si3N4 were both existed, sialon phase was formed while Al4O4C was disappeared.
Ablation Behavior of Low Pressure Plasma Sprayed TiB2-MoSi2 Composite Coatings
Authors: Huang Li Ping , Niu Ya Ran , Li Hong , Ren Mu Su , Zheng Xue Bin , Sun Jin Liang
Published: July 2016

In this work, TiB2-MoSi2 composite coatings with various contents of MoSi2 (20 vol. % and 40 vol. %, respectively) were fabricated on SiC coated C/C substrates by low pressure plasma spray (LPPS) technique. The microstructure and phase composition of the coatings were characterized. The ablation behaviors of the composite coatings were evaluated and compared with the pure TiB2 coating using a plasma flame of about 2200°C. The results showed that MoSi2 was uniformly distributed in the TiB2 matrix. All the coatings kept intact after the ablation for 60s - 180s, indicating their excellent ablation resistance. The addition of MoSi2 had great influence on the ablation behavior of the composite coatings. The TiB2 coating gained mass after the ablation. The mass of the TM20 coating increased firstly (60s and 120s) and then decreased at 180 s. Mass loss was observed for the TM40 coating during the whole procedure of ablation test.
Synthesis of Carbon Nanotubes from Phenolic Resin Using Nickel Nitrate as a Catalyst Precursor
Authors: Wang Jun Kai , Deng Xian Gong , Zhang Hai Jun , Li Fa Liang , Tan Cao , Han Lei , Zhang Shao Wei
Published: July 2016

Carbon nanotubes (CNTs) with 20-40 nm in diameter and several micro-meters in length were prepared through catalytic pyrolysis of phenol resin at 400-1000 °C under Ar atmosphere using nickel nitrate as a catalyst precursor. Microstructure and morphology of pyrolysed resin were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the onset and optimal growth temperatures of CNTs were 400 and 800 °C respectively. Moreover, the optimal weight ratio of Ni catalyst to phenol resin was 0.75%.
Preparation and Characterization of Vanadium Pentoxide Hollow Microspheres with Tunable Sizes
Authors: Gong Ming , Wang Chang An
Published: July 2016

V2O5 hollow microspheres were synthesized by a one-step solvothermal method, with the assistance of PVP as the soft template, ethylene glycol (EG) as the solvent, and vanadium (iii) acetylacetonate (acac) as the metal-ions source. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM). The size of V2O5 hollow microspheres, which can be easily tuned by using PVP of different molecular weights, was about 2.5μm, 4.5μm and 6μm when using PVP-K17, PVP-K30 and PVP-K60 as the template, respectively.
Composition, Structure and Electrical Resistivity of ZnO1-x Films Deposited by RF Magnetron Sputtering under Various O2/Ar Gas Ratios
Authors: Wang Yang , Peng Zhi Jian , Wang Qi , Fu Xiu Li
Published: July 2016

ZnO1-x thin films were deposited by RF magnetron sputtering on conducting silicon wafers at room temperature with ZnOn (n≤1) target under an atmosphere of O2/Ar ratio varying from 0 to 2.0. The correlation between composition, structure and electrical resistivity of the obtained films was investigated. X-ray diffraction analysis revealed that the prepared würtzite ZnO1-x films had c-axis preferential growth orientation. When the O2/Ar ratio was lower than 0.5, the main form of defects in the films was oxygen vacancy; when it was 0.5, the composition of the film approached to the stoichiometric ZnO and had the least number of defects; after that, the main type of defects in the films was interstitial zinc. Thus, with increasing O2/Ar ratio, the electrical resistivity of the films increased first and then decreased.
Control of Preferential Orientation of La1-xSrxMnO3 Thin Films by Pulsed Laser Deposition
Authors: Zhu Ya Xiang , Wang Chuan Bin , Shen Qiang , Zhang Lian Meng
Published: July 2016

La1-xSrxMnO3 (LSMO) thin films were grown on (100)- and (110)-oriented MgO substrates by pulsed laser deposition, so as to control the preferential orientation of the films. At the optimum deposition temperature (Td = 923K), LSMO thin films with a dense texture and a smooth surface were prepared. The XRD patterns and X-ray pole figures indicated that the LSMO thin films were epitaxially grown on MgO substrates, due to the small lattice mismatch between the films and substrates The possible orientation relationships were found to be LSMO (100) [100] // MgO (100) [100] and LSMO (110) [110] // MgO (110) [110], as for the (100) and (110) MgO substrates, respectively.
Study on Zeolite X Complexing Dimethyl Potassium
Authors: Hu Yue , Chen Nan Chun , Xu Hui , Yang L.J. , Ma L.L. , Wu C. , Luo S.J. , Pei Y.C. , Gao S.S.
Published: July 2016

The study took zeolite X as carrier and chitosan as intermediate to compound dimethyl potassium to prepare zeolite X antimicrobial agent by hydrothermal synthesis. The best condition to prepare zeolite X antimicrobial agent is: Mass ratio of zeolite X:Chitosan:dimethyl potassium is 3:1:2, temperature is 40 °C and time is 2 h. Through antibacterial test, we can see that the best inhibitory rate is 78.16%, and release effect significantly enhanced. We studied the structure of zeolite X antimicrobial agent by IR, XRD, SEM, XPS. It can be concluded that: The H on amino-group of chitosan can form hydrogen bonds with O on dimethyl potassium and zeolite X and the hydrogen bonds Play a major role in connecting dimethyl potassium and zeolite X; Free hydroxyl on zeolite X can form hydrogen bonds with O in C-O of chitosan. And it may form hydrogen bonds with O in C=O of dimethyl potassium. And explain the reason of improving of antimicrobial.
Influence of Pre-Oxidation on the Morphology of Mesocarbon Microbeads
Authors: Zhu Ya Ming , Zhao Xue Fei , Gao Li Juan , Lai Shi Quan , Lian Yun Yun
Published: July 2016

Mesocarbon microbeads (MCMB) were prepared from medium coal tar pitch by hot-treatment under certain conditions. The TG, SEM, EDX, Laser Particle Size Analysis and XRD methods were used to characterize the MCMB. The results have been shows that the pre-oxidation treatment before carbonization has a considerable effect on the morphology of MCMB; compared with the MCMB which have no pre-oxidation treatment, the surface of MCMB with pre-oxidation treatment became smoother and the surface defects decreased obviously. Pre-oxidation treatment have been narrowed the particle size distribution of MCMB. Briefly, the average particle size of MCMB with pre-oxidation is 19.751 μm, slightly larger than the untreated MCMB which has the average particle size of 18.442 μm.
Processing and Thermal Properties of Multiwall Carbon Nanotube/Bismuth Antimony Telluride Composites for Nuclear Energy Applications
Authors: Ahmad Kaleem , Wan Chun Lei , Al-Eshaikh Mohammad A. , Kadachi Ahmed N. , Khan Rawaiz , Abdo Hany S.
Published: July 2016

In this work the effects of ball milling and carbon nanotubes incorporation on the thermal conductivities of the bulk BiSbTe composites were evaluated. The coarse BiSbTe particles were obtained by crushing BiSbTe lumps and subsequently high energy ball milling was employed in an inert environment to form the fine BiSbTe powder. Multiwall carbon nanotubes in different (0.0, 0.5 and 1.5) vol. % were uniformly mixed in the BiSbTe powder through a combination of ultra-sonication and ball milling, and then processed by rapid high frequency induction heated sintering (HFIHS) to achieve fully dense nanocomposite. Thermal diffusivity of the composites was evaluated and heat capacity was approximated using Pyrocerarm as a reference material. The effect of carbon nanotubes inclusion and BiSbTe particle size reduction on the thermal conductivity was studied from 300 to 500 K. The results show a significant reduction in the thermal conductivity due to the enhanced thermal boundary interface resistance correlated with the fine microstructure/nanostructure in the composites as compared to pristine bulk bismuth antimony telluride.
Preparation of UCO Microspheres by Internal Gelation Process
Authors: Zhao Xing Yu , Ma Jing Tao , Gao Yong , Hao Shao Chang , Deng Chang Sheng , Liu Bing , Tang Ya Ping
Published: July 2016

UCO kernels were used for High Temperature Reactor (HTR) fuel, which can restrain kernels migration and avoid corrosion of cladding layer under the high burnup compared with UO2 or UC kernels. In this paper, UCO kernels were prepared by internal gelation process containing dissolving, broth preparation, dispersing, AWD (aging, washing and drying) and sintering procedures. The broth composition was studied based on the fabrication of UO2 kernels before. Effects of the carbon black content and sintering atmosphere on the microstructure and performance of microspheres were mainly studied. Surface morphology of dried microsphere was observed by integrated microscope. Grain size and the degree of densification of UCO microspheres were observed by SEM.
BiFeO3 Powders Synthesized by Different Sol-Gel Methods
Authors: Bao Li , Qi Xi Wei , Ni Bo , Zhang Min , Mei Rui Bin
Published: July 2016

The multiferroic BiFeO3 powders with perovskite structure were synthesized by sol-gel auto-combustion and conventional sol-gel methods, respectively. As-prepared powders were characterized by XRD, SEM and VSM techniques to investigate phase structure, microstructure and magnetic properties. The results show that the pure phase BiFeO3 powders are obtained successfully by sol-gel auto-combustion after calcining at 650°C for 2h and leaching by HNO3. Compared with conventional sol-gel method which got pure phase BiFeO3 powders at 800°C for 3h, the sol-gel auto-combustion technique can get more pure powders at low temperature, short time and low cost. The particle sizes of the BiFeO3 powders are smaller and well distributed by the sol-gel auto-combustion method than that of the conventional sol-gel method. Furthermore, the magnetic properties at room temperature prepared by the sol-gel auto-combustion methods are significant higher than that of conventional sol-gel method.
Preparation and Microstructure of (La0.5Sm0.5)2(Zr0.7Ce0.3)2O7 Ceramics Prepared by Chemical Coprecipitation Method
Authors: Sun Xian Kai , Wang Guang Hai , Zhang Shi Chao , Sun Hao Ran , Fang Kai , Chen Yu Feng
Published: July 2016

Ceramic materials of (La0.5Sm0.5)2(Zr0.7Ce0.3)2O7 composition powder was synthesized by chemical coprecipitation method using Sm2O3, La2O3, Ce (NO3)3·6H2O and ZrOCl2·8H2O powders as raw materials. Microstructure and phases of (La0.5Sm0.5)2(Zr0.7Ce0.3)2O7 (LSZCO) powder was examined by Transmission Electron Microscope (TEM) and X-ray diffraction (XRD). The specific surface area of powders were determined by BET specific surface area test. The structure of LSZCO powder remained in pyrochlore with the increase of temperature more than 1200 °C. According to the impact on the specific surface area of LSZCO powder, the factors of the process is ordered in descending sequence as follows: pH value, dispersant content, concentration of reactants, the reaction temperature.
Investigation of Aramid Fibers Compared with Steel Fiber on Bending Behavior of Hybrid RC Beams
Authors: Chan Ly , Tanapornraweekit Ganchai , Tangtermsirikul Somnuk
Published: July 2016

This paper presents an experimental study on bending behavior of aramid and steel fiber reinforced concrete (AFRC and SFRC) members. The objective is to investigate effects of two types of aramid fiber and one type of steel fiber in hybrid reinforced concrete (RC) beams. The term hybrid beam is defined as the beam with fiber reinforced concrete (FRC) cast in tension zone and normal concrete (without fiber) cast in compression zone of the beam. The diameter of aramid fiber (AF) is 0.5mm and the surface condition is twist fiber consisting of two single fibers. The fiber lengths are 30mm and 40mm for two types of aramid fiber. The diameter of steel fiber (SF) is 0.6mm and the length is 33mm with hooked ends. Four reinforced concrete (RC) beams with a dimension of 150×200×2100 mm3 were designed to undergo flexural failure. All the tested beams are with the same reinforcement ratio (0.93%), having a fiber volume fraction (Vf) of 1% for each type of fiber. One RC beam without fiber was prepared and tested as a controlled specimen. The height of the FRC tension zone at ultimate state was calculated to be 170mm. Load capacity, average and maximum crack widths of hybrid aramid and steel fiber reinforced concrete beams (HAFRCs & HSFRC) under four-point bending tests were discussed.
Study of Box Girder Steel Structure Locally Reinforced by CFRP
Authors: Liu Zhi Ping , Li Zongchen , Li Ming Chang , Chen Kai , He Chao Chao
Published: July 2016

On the basis of using CFRP (Carbon Fiber Reinforced Polymer) to reinforce steel materials and structures, this paper focused on the reinforcement method of box girder steel structure. Firstly, FEM models were set up to discuss the reinforce method, stress distribution between overall strengthening of flange and locally strengthening. Secondly, typical crack model was raised on the basis of mechanics characteristic, reinforcement effects under different methods was analyzed. The results showed that locally strengthening method to reinforce the certain fatigue areas could improve stress concentration phenomenon and SIF effectively. This paper offered a significant basement for reinforcing box girder steel structures and repairing fatigue cracks using CFRP.
Effect of Weathering on the Mechanical Properties of HDPE/Rice Straw Composite
Authors: El Shazly Yehia M.S. , El Nemr Mohamed H. , Mubarak Ashraf A. , Zaki Mohamed H.
Published: July 2016

In recent years, Wood Plastic Composite (WPC) has found widespread applications in the field of construction, decoration and furniture. In this work, the effect of weathering on the mechanical properties of WPC made from high density polyethylene (HDPE) and rice straw particles (RS) has been studied. Different loading of composite (20, 35 and 50% RS) were tested. Polyethylene wax (PE-wax) and UV-stabilizer were also added to assess their effect on the WPC composite.
Shungite Nanopowder as a Modificator of Mechanical Properties and Water Absorption for Three-Ply Particle Board
Authors: Vasilyev Sergey Borisovich , Kolesnikov Gennady Nikolaevich , Pitukhin Aleksandr Vasilyevich , Panov Nikolai Gennadievich , Kostyukevich Vadim
Published: July 2016

The article presents the methods and the results of the experimental investigation of the additive influence of shungite nanopowder when mixed in the glue for three-ply particle board. The hypothesis of shungite nanopowder influence on physical-mechanical properties, water absorption and thickness swelling of wood particle board was formulated. The results of experimental investigations proved that the optimum shungite nanopowder quantity in glue solution makes up about 10 % of absolutely dry resin mass. Wooden particles of aspen and coniferous species, as well as glue solution based on carbamide-formaldehyde resin, were used in boards manufacturing. The samples were tested in order to determine physical-mechanical properties. It was found out that the 10 % shungite nanopowder additive increases the breaking point of three-ply particle board under bending strength by 18.3-25.7 %, the breaking point of three-ply particle board under tension perpendicular to the face of board by 7.5-11.7 %. As the result of experimental investigation it was found out that the 10 % shungite nanopowder when mixed in the glue decreases water thickness swelling of three-ply particle board up to 14.2 % and water absorption by 10.6-20.1 %. The shungite nanopowder powder contained particles of 50...100 nm in size and specific surface of 120 m2/g. In the course of the experiment three-ply particle boards were used with the thickness of 15.6 mm.
Optimization of Tin Magneto Electrodeposition under Additive Electrolyte Influence Using Taguchi Method Application
Authors: Sudibyo Sudibyo , Nurjaman Fajar , Aziz Norashid
Published: July 2016

Operational conditions of tin magneto electrodeposition were successfully obtained using Taguchi technique. The parameters which optimize using Taguchi orthogonal array were tin sulphate, sulphuric acid, gluconate concentrations and magnetic strength (Tesla). The gluconate in this process is additive electrolyte which acts as an inhibitor against corrosion. The effects of those parameters toward the fractal dimension of tin electrodeposits were studied in this research. The results show that microstructures of tin electrodeposit from magneto electrodeposition have a compact structure than the tin electrodeposits of conventional electrodeposition.
Study on the Simplification of Spiral Bevel Gear Grinding Model
Authors: Wang Chang Sheng , Yao Peng , Wang Jun , Huang Chuan Zhen , Liu Han Lian , Zhu Hong Tao , Zou Bin
Published: July 2016

Gear grinding is expensive and difficult to research due to its complex kinematics and meshing theory. In the paper, a simplified method based on the meshing model of spiral bevel gear system is presented. With the relative speed and normal curvature of tooth surfaces and grinding wheels on meshing point deduced from differential geometry theory and grinding parameters, the spiral bevel gear grinding can be simplified to fundamental grinding process like surface, cylindrical and internal grinding, which may be utilized to perform experimental investigation on mechanism of gear grinding.
Surface Morphology of Silicon Induced by Laser Ablation in Flowing Water
Authors: Charee Wisan , Tangwarodomnukun Viboon
Published: July 2016

Underwater laser machining process has a high potential over the typical laser ablation to remove materials with less thermal damage occurring along the cut. However, the formations of vapor bubble and cut debris in water can substantially disturb the incident laser beam, thereby reducing the ablation performance. Instead of performing the ablation in still water, the flowing water technique was applied to flush away the cut debris and bubble generated. In this study, the effects of laser pulse energy, traverse speed and water flow rate on the cut surface roughness and heat-affected zone in the laser grooving of silicon were experimentally investigated and analyzed. The findings revealed that the cut surface roughness decreased with the increases in laser pulse energy and laser traverse speed. Though a higher water flow rate resulted in a rougher cut surface, the heat-affected zone can be minimized when the increased flow rate was applied.
The Effects of Ultrasonic Vibration in Hot Pressing for Microgrooves
Authors: Xie Jia Qing , Zhou Tian Feng , Liu Yang , Kuriyagawa Tunemoto , Wang Xi Bin
Published: July 2016

Microgrooves with a pitch at wave length level are increasingly needed in the optical system. Conventional, the microgroove forming accuracy is low due to the incomplete filling of the material in the cavity of microgroove mold, and surface flaws occur easily due to the adhesion of the resin material to the mold surface. In this research, the response behavior of resin material subjected to alternating stress is resolved based on Generalized Maxwell model. Finite Element Method (FEM) simulation is carried out to test the microgroove forming effects under the pressing condition without and with ultrasonic vibration. An ultrasonic assisted pressing machine is developed and used to fabricate microgrooves on methacrylic resin surface. Form accuracy and surface quality of microgrooves are confirmed to be improved by comparing the ultrasonic assisted pressing with the conventional forming.