bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Temperature Synthesis of Magnesium Aluminate Spinel from AlOOH and MgO Powder
Authors: Wang Xiu Hui , Lu Sheng Bo , Wang Cheng Min , Yu Hong Bo
Published: September 2009

Ultrafine MgAl2O4 powders have been successfully synthesized by solid-state reaction from the mixture of AlOOH and MgO at the lower temperature. The samples were investigated by DTA/TG、XRD and SEM analyses. The results showed that AlOOH can be decomposed into γ-Al2O3 from DG/TDA curves, which can improve the activity of Al2O3 and promote the process of solid-state reaction. The XRD analysis showed the single-phase MgAl2O4 was formed at 1400°C. Meanwhile it was detected by ICP-MS that the purity of powders was 99.995%. The SEM images showed that the mineralizer containing fluoride such as AlF3, NH4F can promote the resultant to grow into regular octahedrons and disperse the particles. The XRD analysis indicated the mixture containing 5% AlF3 can transform the integrated MgAl2O4 powders at 1200°C, nearly 200°C lower than general solid-state reaction. Furthermore, The SEM images showed that fluoride can crystal the fine particles into the larger MgAl2O4 crystals, about 0.5～1.5µm.
Oxygen Reduction Electrocatalysts Based on Two-Dimensional Iron Polyphthalocyanine
Authors: Xu Guo Feng , Li Zhong Fang , Wang Su Wen , Yu Xian Jin
Published: September 2009

Two-dimensional iron polyphthalocyanine(PPcFe) was synthesized by heating iron (II) phthalocyanine tetracarboxylic acids at 400°C in argon atmosphere. The polymer was characterized and analyzed by UV-Vis, FT-IR, XRD and TG. UV-Vis absorption spectra of iron phthalocyanine showed that absorption bands appeared at higher wavelengths than monomer phthalocyanine. The result of IR indicated that the absorption peaks corresponding to the carboxylic acid groups decreased and the characteristic phthalocyanine ring absorption bands were observed. The DTA data for PPcFe showed exceptional thermal stability.
PPcFe, monomer phthalocyanine(PcFe) and dinuclear iron phthalocyanine(DPcFe) were adsorbed on the Vulcan XC-72 carbon and then heat-treated at 400°C in argon atmosphere to prepare catalyst. The electrocatalytic activity was investigated using linear scan voltammetry(LSV) in 0.5M H2SO4. The polarisation curve of oxygen reduction on the FePPc/C catalyst in O2-saturated H2SO4 was compared to that obtained on PcFe, DPcFe and platinum catalysts. Results showed that it possessed higher catalytic activity than PcFe and DPcFe catalysts. LSV at different electrode rotation rates led to determine the Koutecky-Levich plots from which it was shown that the kinetic parameters for the ORR at FePPc/C electrodes are similar to those obtained at 30wt% Pt/C.
Low Velocity Impact Damage Evaluation of 2D C/SiC Composite Material
Authors: Yao Lei Jiang , Feng Zi Yang , Cheng Qi You
Published: September 2009

Three non-destructive test (NDT) methods were used to detect the two dimensional C/SiC specimens after low velocity impact (LVI) of various energies. The damage areas characterized by these methods were very different. Both ultrasonic and thermographic images reveal the LVI damages, while X ray is non-sensitive to the interior damage. However, small delaminations were not found by thermography and accurate judgment depends on the experience and the resolution of the infrared camera. And the result acquired from the higher frequency transducer was very confused because of the inherent defects. It is suggested that using both ultrasonic C-scan and thermography to evaluate the LVI damage of C/SiC. It is also suggested using the transducer of low frequency to perform the ultrasonic C-scan.
Fabrication of Polystyrene-Encapsulated Nanodiamond via In Situ Latex Polymerization and their Wettability Evaluation
Authors: Bai Bo , Wang Peng Peng , Yang Li , He Yong Jun
Published: September 2009

Nanodiamonds coated with polystyrene were prepared by in-situ latex polymerization using azobisisobutylonitrile as initiator in alcohol-water solution. The products were characterized by transmission electron microscope, X-ray diffraction, thermo-gravimetric and differential thermal analysis and Fourier transformation infrared spectrum. A possible formation mechanism and the structure of products were proposed. The experimental evaluation of wettability performance showed that the hydrophobicity of nanodiamond have been enhanced with the wrapping of polystyrene films on the surface of nanodiamond particles.
Growth of Carbon Nanocoils Using Chemical Vapor Deposition
Authors: Su C.C. , Hsieh Y.L. , Chang S.H.
Published: September 2009

We present the synthesis of carbon nanocoils using the chemical vapor deposition technique with metal catalysts on silicon substrates. The optimum synthesis conditions and coil geometry are summarized. The coils have distribution of the outside diameter of 300 nm to 1200 nm, wire diameter of 150 nm to 400 nm and the pitch of the coil of 150 nm to 1200 nm. Applications of the developed carbon nanocoils can be electro-mechanical sensing and the electro-magnetic insulation.
Flexural Testing of Fiber Reinforced Polymer-Concrete Composite Bridge Superstructure
Authors: Wang Yan Lei , Hao Qing Duo , Ou Jin Ping
Published: September 2009

The concept of the fiber reinforced polymer (FRP)-concrete composite design was exploited in a new type of bridge superstructure. The proposed FRP-concrete composite bridge superstructure is intended to have durable, structurally sound, and cost effective composite system that will take full advantage of the inherent and complementary properties of FRP material and concrete. As a trial case, a prototype bridge superstructure was designed as a simply supported single-span one-lane bridge with a span length of 10 m. The bridge superstructure consists of two bridge decks and each bridge deck is comprised of four FRP box sections combined with a thin layer of concrete in the compression zone. A test specimen, fabricated as a one-third scale model of the prototype bridge superstructure, was subjected to four-points loading to simulate the two heaviest axles of the Chinese design truck load. The test results indicate that the proposed bridge model meets the stiffness requirement and has significant reserve strength.
Magnetic Shape Memory Alloy and Application in Structural Vibration Control
Authors: Weng Guang Yuan , Wang She Liang
Published: September 2009

Magnetic Shape Memory Alloys (MSMA) are attractive active materials because they have large strain (about 10%) as the classical shape memory alloys (SMA), but can provide a 100 times shorter time response, so, MSAM will be the ideal material of structural engineering vibration control. The main disadvantages of MSMA based actuators are the brittleness of the single-crystal material, the difficulty to apply the strong magnetic field required to obtain sufficient strain and the nonlinear behaviors. In this paper a novel MSMA based actuator changing the disadvantage of the hysteretic behaviors into an advantage. This device includes two pieces of MSMA material act in an opposite way. The hysteretic behavior of the material permits to keep a stable position when no current is applied. The use of current pulses permits also a reduction of the coil heating (Joule effect losses) and a reduction of the magnetic circuit size. The performances and characteristics of MSMA are between these of classical SMA and these of piezo-electric materials. A thermo-magneto-mechanical model of the actuator is currently in development in order to design an efficient control law well adapted to the specific MSMA properties.
Preparation of Low Chlorine Shellac from Seedlac by Dechlorination Process Using Pd/Fe Binary Metal as Catalyst
Authors: Liao Ya Long , Xu Fu Chang , Li Dong Bo
Published: September 2009

Pd/Fe bimetallic catalysts were synthesized via chemical deposition and used to eliminate chlorine compacted in shellac while it was being bleached with sodium hypochlorite in alkaline solution for the preparation of low chlorine shellac, a natural and biological product used in large scale in food industry and pharmaceutical fields. Experiments demonstrated that the Pd/Fe bimetallic particles could catalyze dechlorination process effectively, which was affected by several factors such as reaction temperature, Pd/Fe ratio, and the induction of Pd/Fe. The dechlorination efficiency reached 81.9% under the conditions of Pd/Fe loading ratio of 0.10wt%, binary metal usage 10 g/L, H2 flowing rate 50 mL/min, and reaction temperature 90°C for 240 min. Moreover, the mechanism of catalytic hydrogenation was elucidated through structure characterization of the final products using elementary analysis, infrared spectroscopy, and ultraviolet spectrophotometer. It was shown from the result of ultraviolet spectrophotometer that the wavelength of the maximum absorption of seedlac, the raw materials for obtaining shellac, was 235 nm. However, it was blue shifted to the same value 222 nm when the shellac was dechlorinated by catalytic hydrogenation with Pd/Fe binary metal particle as the shellac without catalyzed. The results of elementary analysis showed that chlorine content in the final product was only 0.46%, just 1/5 comparing to that of non-declorination by catalytic hydrogenation under the optimum conditions. It was shown that the chlorine ions compacted in the shellac was substituted by hydrogen ions.
Improvement on the Efficiency of Drawing during the Production of Microfibrillar Composites
Authors: Lin Richard , du Preez Stuart , Slaats James , Bhattacharyya Debes
Published: September 2009

The feasibility of manufacturing microfibrillar composites (MFCs) and their novel applications have been studied to a significant extend. In order to achieve commercially viable production rate of MFC materials, consistent fabrication has to be guaranteed. However, it has been shown that continuous production of MFC materials has certain difficulties need to be overcome. This study aims at identifying the production problems and improving the efficiency of manufacturing MFC materials.
MFC manufacturing has been reasonably successful by drawing poly(ethylene terephthalate) (PET)/polypropylene (PP) blends. However, when the PP in the polymer blends is replaced by polyethylene (PE) for its ease of subsequent manufacturing, irregular breakage persistently occurs during drawing and this phenomenon also occasionally happens for PP/PET blends.
This study involves melt blending of linear low density polyethylene and linear medium density polyethylene with PET in a single screw extruder with 70/30 wt%. Drawing was conducted at temperatures ranging from room temperature to 70°C and with draw ratios of between 1:5 and 1:7. The test results, when comparing MFC with pure PE, show 60% and 80% increase in specific tensile strength and specific tensile stiffness, respectively. It is concluded that by carefully controlling the temperature profile within the drawing chamber and using a moderate draw ratio (1:5), an efficient drawing process can be achieved to produce commercial MFC materials.
Thermal Parameters of Sweat Lubricating Composite and its Effect on High Temperature Rolling Bearing
Authors: Lu Yan , Liu Zuo Min
Published: September 2009

The thermal parameters of sweat self-lubricating composite and its effect on high temperature rolling bearing have been investigated in the paper. A new expression of describing the contact area of the rolling bearings has been developed and used to calculate the change value of the contact area with temperature. The result indicates that the thermal parameters of the sweat self-lubricating composite greatly improve the contact area of the bearings by comparing with the material M50, the increase rate of contact area is lower than that of M50.
Research on the Growth Mechanism of Alumina Ceramics with Columnar Grain
Authors: Rong Shou Fan , Zhu Yong Chang , Zhang Jing Qiang , Liu Hong Li , Shi Chun Yan
Published: September 2009

Based on the structures and composition of ceramic materials, the microstructure design and new preparations were used to induce in situ grain growth by adjusting the main factors which had impacts on grain morphology. By adding CAS (CaO-Al2O3-SiO2) and Nb2O5, the complex toughened alumina ceramics with columnar grain was fabricated under pressureless sintering systematically. The influences of additives on the alumina ceramics with columnar grain were analyzed by means of TEM, SEM, XRD etc. The dynamic conditions of anisotropic growth of columnar grain were researched, and superior growth in some grain directions was induced by doping CAS and Nb2O5. The growth mechanism of columnar grains of alumina ceramics was explored, and established growth model.
Research on Zinc-Silica Composite Plating
Authors: Fan Yun Ying , Zhang Ying Jie , Dong Peng
Published: September 2009

In order to explore a new kind of high anti-corrosion and environmentally benign materials to protect steel, zinc-silica composite coatings were prepared by plating technique. In this paper, experiments on electrodeposited zinc-silica composite coatings are reported, effects of cathodic current density, agitation, additive, anode number, space between anode and cathode on the appearance of coatings are discussed, composition and property of zinc-silica composite coatings are investigated. The electrolyte composition and operating conditions are: ZnCl2　80 g/L, KCl　220 g/L, additive 10 ml/L, SiO2 2~3 g/L, pH 4~5, current density 140~180 A/m2, temperature 15~35°C, 20~30 cm space between anodes and cathodes, once plating time is 60 min.The content of silica in coatings is 0.47~0.56%(mass), the thickness of coatings is 20~23 μm, and the time of composite coatings appearing red rust in neutral salt spray test(NSS) keeps more than 410 h. During the experiment lasting for 30 days, pH value and composition of the electrolyte and deposition speed of coatings all keep relatively stable. Further more, this composite plating technique can reach the first National Entironment Standard(GB 8978–1996). All the results show that zinc-silica composite coatings with no chromate treatment have better corrosion resistance than zinc coatings, stability of this composite plating technique is satisfactory, maintenance operation is convenient, and the plating process is innocuous and safe, so this technique will undoubtedly has a great future in application.
Experimental Research on the Preparation of Porous Activated Carbon from Orange Wastes
Authors: Xie Zhi Gang
Published: September 2009

Porous activated carbon was prepared from orange wastes using zinc chloride as an activating agent by one-step carbonization method. Effects of impregnation ratio, carbonization temperature and heat preservation time on pore characteristics of activated carbon were studied. The porous structures of the orange wastes activated carbon were investigated by BET, D-R equations, BJH equations and Kelvin theory. The morphology was observed using transmission electron microscopy (TEM). The mesoporous activated carbon is gained when the impregnation ratio is 3:1; the carbonization temperature is 550°Cand heat preservation time is 1.0 h. The activated carbon has total pore volume 2.098 cm3/g, mesoporous pore volume 1.438 cm3/g, with a high BET surface area 1476m2/g. The pore distribution of the mesoporous activated carbon is very concentrative, with average pore diameter of 3.88nm. While, the high specific surface area activated carbon is gained when the impregnation ratio is 2:1; the carbonization temperature is 550°Cand heat preservation time is 1.0 h. The activated carbon has high BET surface area 1909 m2/g, while the total pore volume is only 1.448cm3/g and microporous pore volume is 0.889cm3/g, with average pore diameter of 2.29 nm.
Effects of Different Cooling Rate and Modifiers on the Microstructures of 4Y32 Aluminum Alloy
Authors: Wang Gao Song , Zuo Yu Bo , Zhao Zhi Hao , Cui Jian Zhong
Published: September 2009

This paper discussed the effects of different cooling rate on the microstructure of the 4Y32 aluminum alloy and the refinement and modification on 4Y32 aluminum alloy by using Na and Al-10%Sr master alloys in various treatment states. And also the effect of Al-10Sr and Al-3Ti-1B compound modification on microstructures of 4Y32 aluminum alloy has also been studied. The results showed that: the primary silicon was eliminated during slow cooling. As the cooling rate increased, the number of primary silicon was also growing, but the size of primary silicon and eutectic silicon were significantly refined; when without modification, the shape of eutectic silicon was needle and flake; 4Y32 aluminum alloy could be effectively refined after Na modification, under the optimum addition amount of 0.8wt%. The best modification was achieved with 15 minutes, that is, the shape of primary silicon changed to small granular or oval and the primary silicon was eliminated; the as-cast structure has been improved after Al-10Sr modification, under the optimum addition amount of 0.2wt. %, the shape of eutectic silicon changed to fine short rod or point and the primary silicon was eliminated; However, in the compound modification, efficiency of Sr was decreased with the increasing additional amount of AI-3Ti-1B master alloy, which was attribute to the interaction of Sr and Ti.
Influence of Dye-Polyether Derivatives Architecture on Parent C. I. Disperse Yellow 64 Dispersion
Authors: Dong Xia , Zheng Zhao He , He Jin Xin
Published: September 2009

Interface stability has been the subject of extensive investigation by the scientists working in the field of micron or nanometer materials for centuries and the control of the colloidal properties and stability of particle dispersions is of significant importance in the manufacture of high quality water-based dispersions or solvent-based systems. The waterborne dispersion of C.I. Disperse Yellow 64 requires the use of dispersant additives. By the reaction of C.I. Disperse Yellow 64 with poly(oxyalkylene)-amines, a series of dye-polyether derivatives, supposed to be used as dispersants for parent dye dispersions, was synthesized and subsequently characterized by amine titration, SEC and 1H NMR. The polyethers chosen are polyoxyethylene-polyoxypropylene diblock coploymers with different molecular weights and degrees of hydrophilicity/hydrophobicity in the backbones. The influence upon adsorption of dye-polyether derivatives on the dispersion behavior of parent C. I. Disperse Yellow 64 has been investigated. A range of experimental methods including adsorption isotherms, dispersion stability test, and particle size measurements were used to assess the dispersion effect of the dye-polyether derivatives. Adsorption of dye-polyether derivatives onto the parent dye surface is little affected by the molecular weight and increases with the increasing hydrophobicity of the polyether. The dispersion stability of the parent C.I. Disperse Yellow 64 dispersions has considerably been improved by the presence of all the dye-polyether derivatives. In particular, the dye-polyether derivatives exhibited excellent dispersive capacity for the dispersions even at a dye to dispersant weight ratio of 10:1, which largely reduced the dispersant demand compared with the commercial dye. This new strategy of the dye-polyether derivative as dispersant for its parent dye will result in significantly alleviating the environment pollution from dyeing effluent and is not only expected to be applicable to dispersion of other water-insoluble dyes in aqueous media, but also a new promising candidate for the stablization of micron or nanometer materials.
Dry Sliding Wear Behavior of Fe3Al Intermetallics Prepared by Mechanical Alloying and Hot Pressing
Authors: Li Jing , Yu Kuan , Lei Shi , Ma Zhong Quan
Published: September 2009

Fe3Al intermetallics with different Al contents were prepared by mechanical alloying and hot pressing. The phases and dry sliding wear behavior were studied. The results show that Fe3Al bulk materials are mainly characterized by the low ordered B2 structure. The wear resistance increased with increasing Al content, with the lowest volume loss of Fe-32Al and irregular value of Fe-30Al. There were obvious differences in wear mechanisms of sintered Fe3Al under different testing conditions. Under lower loads plastic deformation occurred on the wear surface and the wear performance is mainly particle abrasion, the characteristics of which are micro cutting and furrows. With higher loads, the stress concentration led to rapid crack propagation and eventually the fatigue fracture, which was characterized by brittle split of material.
Carbonate Steelmaking Slag to Manufacture Building Materials
Authors: Wu Hao Ze , Chang Jun , Pan Zheng Zhao , Cheng Xin
Published: September 2009

Accelerated carbonation is a new technology of materials preparation, which may have potential for the treatment of industrial solid residues and the sequestration of CO2, an important greenhouse gas. In this study, accelerated carbonation was used to recycle steelmaking slag and sequestrate CO2 to manufacture building materials. The experimental results show that the strength of specimens increases along with the increase of carbonation degree. Moisture content, carbonation temperature and curing time have significant effects on the degree of carbonation, and carbonated specimens have larger weight increase and compressive strength increases under the condition of moisture content 12.6%，reaction time 117 min and reaction temperature 361 K. The SEM and XRD analyses indicate that dogtooth like CaCO3 crystals appear on the surface of carbonated aggregate specimens. Strength and soundness test shows that steelmaking slag building materials have higher strength and eligible soundness after accelerated carbonation.
Mechanism of Steel Corrosion Inhibition Using Mannich Bases
Authors: Bogatu Cristina , Manciulea Ileana , Duta Anca
Published: September 2009

The paper presents the results obtained when using Mannich bases (and derivatives) as corrosion inhibitors in saline environment, for different types of steels, with various alloying elements. The Mannich basis (ketonic combinations with naphtenic and nitrogen containing rings) were synthesized as such (polar) and as chlorhydrates (ionic) and used in corrosion experiments, in concentrations varying from 0….1300 ppm. The corrosion experiments were performed by potentiodynamic polarization studies. Based on the polarization curves, the corrosion current density and rate were calculated. The inhibitor efficiency was evaluated and based on these values the protection mechanisms was discussed.
Wet Surface Modification of Light Calcium Carbonate Powder by Aluminate Coupling Agent
Authors: Li Lang Chen , Zhang Yue
Published: September 2009

The modification of light calcium carbonate powder was studied by wet surface modification in n-Butanol and water solution. The modification process was analyzed by modifying temperature, rotation speed, aluminate coupling agent dosage and n-Butanol percentage. The characters of modified calcium carbonate were investigated by the contact angles with water/glycerol/liquid paraffin/DOP and infrared spectroscopy (IR). The contact angles/water of modified CaCO3 powder obtained in optimum conditions was 134.5°. The results indicated that the surface property of CaCO3 powder changed from the hydrophilicity to the lipophilicity.
Process Optimization of Preparation and Performance Characterization of Oily Sludge-Based Adsorbent Material by Pyrolysis
Authors: Zhang Guang Ying , Hou Ying Fei , Li Chun Hu , Zhu Wei , Zhang Jian
Published: September 2009

The oily sludge-based adsorbents for flue gas desulfurization were prepared by pyrolysis. Based on benzene adsorptivity, the conditions of pyrolysis process were optimized. The optimum prepared conditions of adsorbent material were in nitrogen atmosphere and 550°C, 4h, 10°C/min for the pyrolysis temperature, pyrolysis time and heating rate, respectively. In this case, the maximum benzene adsorbability was 60.12mg/g. Moreover, the main influencing factor was pyrolysis temperature, secondly was pyrolysis time and finally was heating rate. The sludge-based adsorbents were appropriate for flue gas desulfurization. The sulfur capacity of adsorbents via a flue gas desulfurization test after subsequent processing was about 3% and breakthrough time could keep to 109 min.
Superdeep Penetration - Novel Method of Nanoreinforced Composites Producing Based on Metallic, Ceramic and Polymer Matrixes
Authors: Figovsky Oleg , Usherenko Sergey
Published: September 2009

Now there is a motivation for creation of the materials possessing a considerable difference of physical and chemical properties in volume of composite materials 1 . Composite materials allow realizing a complex of various properties which cannot be realized simultaneously in mono material. The perspective in reception of a new smart nanomaterial is basically defined by possibilities which create processing conditions Choosing and manufacturing of fibers refers to the second stage of composite material reinforcement. Process of assemblage of a composite material from the details made at first two stages of process refers to the third stage. But at each stage of process of manufacturing of a composite material there are specific problems. The basic problem at composite material creation, as a rule, is essential contradictions between engineering solutions for various stages of process.
Fabrication of (TiB2, TiCx)/B4C Composites via Ti3Al IMC Added in B4C Ceramics
Authors: Yin Yan Sheng , Zhang Wei Ke , Dong Li Hua , Lei Yan , Li Jian , Xiao Liu
Published: September 2009

Ti3Al inter-metallic compounds were successfully prepared via high energy ball milling and the subsequently heat treatment. Near full dense (TiB2, TiCx)/B4C matrix composites were fabricated by the addition of Ti3Al. The maximum values of hardness, flexural strength and fracture toughness are HRA 94.1, 580.34MPa and 8.07MPa•m1/2 respectively for 20wt% Ti3Al content. Furthermore, the microstructures of the composites were analyzed by XRD, SEM and energy spectrum methods.
Effect of Small Addition of Niobium on the Mechanical Properties of FGBA/ BG Duplex Phase Air Cooling Bainitic Steel
Authors: Feng Chun , Zheng Y.K.
Published: September 2009

The effect of small addition of niobium on the mechanical properties of grain boundary allotriomorphic ferrite (FGBA)/ granular bainite (BG) air cooling bainitic steel has been investigated by tensile test, Optical Microscopy (OM), and scanning electron microscopy (SEM) observation.
The results show that (1) The small addition of niobium improves the mechanical properties of the FGBA/BG steel obviously. Compared with Non-Nb FGBA/ BG steel, 0.02% Nb increases the tensile strength and yield strength about 20% (From 780Mpa to 937Mpa)and 17%(From 557Mpa to 650Mpa) respectively, remaining 18% elongation. (2) With the addition of 0.02%Nb, both the size and the volume fraction of FGBA decrease. Meanwhile, the volume fraction of refined intragranular ferrite and M-A islands increases. Compared with Non-Nb steel, the volume fraction of M-A island in 0.02Nb steel increases from 21% to 31%, and the average size of M-A island decreases from 1.2μm to 0.95um.(3)It is indicated that the small addition of Nb(0.02%) not only refines the allotriomorphic ferrite grain but also promotes the nucleation of intragranular ferrite, both of which in turn contribute to the refinement of granular bainite cluster including its ferrite platelets and M-A islands. (4)It is suggested that the strengthening effect of 0.02%Nb can be mainly attributed to the segregation of Nb to γ/α phase boundaries(solute drag-like effect) rather than the precipitation strengthening of Nb(C,N). Nb enrichment in the α/γ interphase causes the decrease of C-activities and activity gradient in the austenite matrix around the α/γ interphase and thus causes the decrease of C-diffusion rate in austenite, and further the restraint to ferrite growth. The effects also depress bainite transformation temperature and driving force, as a result, the bainite cluster is refined.
Microstructure and Electrical Properties of La2O3-Doped ZnO-Bi2O3 Based Varistor Ceramics
Authors: Xu Dong , Cheng Xiao Nong , Wang Ming Song , Shi Li Yi
Published: September 2009

La2O3-doped ZnO-Bi2O3-based varistor ceramics were obtained by a solid reaction route, and the microstructure and electrical properties of the varistor ceramics were studied in this paper. The results showed with addition of 0-1.00mol% La2O3, La2O3-doped ZnO-based varistor ceramics were prepared in this paper with the voltage gradient of 77-503V/mm, the nonlinear coefficient of 2.4-36.8, and the leakage current of 0.09-494μA. The results also showed with addition of 0.08mol% La2O3, La2O3-doped ZnO-based varistor ceramics exhibit comparatively ideal comprehensive electrical properties. Such as the threshold voltage was 320V/mm, the nonlinear coefficient was 36.8 and the leakage current was 0.29μA. The doping of La2O3 affects the form and decomposition of the pyrochlore.
Phase Evolution and Sintering Characteristics of Mullite-Based Ceramics Prepared from Coal Fly Ash, Calcined Bauxite and Ball Clay
Authors: Ma Xue , Yao Xiao , Hua Su Dong
Published: September 2009

The study provides a novel way for the utilization of coal fly ash, and enriches the sintering mechanism in preparation of low-cost, high performance mullite based ceramic. The phase evolution, microstructure, densification behavior and flexural strength as a function of the sintering temperatures, were investigated by XRD, SEM and evaluated by density, open porosity and shrinkage and three point bending method, respectively. Secondary mullite nucleates from the dissolution of alumina in transient liquid phase at 1300°C. Above 1400°C, mullite content increases and the densification is promoted with increasing temperature. Fast densification takes place and high flexural strength of 149MPa is achieved at 1600°C.
Synthesis and Characterization of Platinum-Containing Ordered Mesoporous Carbon with High Specific Surface Area
Authors: Ji Zhi Hong , Jiang Yan Bin , Li Hao , Ye Li , Han Wei Jian , Zhao Tong
Published: September 2009

A Pt-containing ordered mesoporous carbon with a high specific surface area was synthesized through evaporation-induced multi-constituent co-assembly method, wherein soluble resol polymer is used as the carbon precursor, silicate oligomers as the inorganic precursor, triblock copolymer as the template, and H2PtCl6•6H2O as the Pt precursor. After thermopolymerization, the template was removed by calcinations, and silica was removed by NaOH solutions. The resultant sample was characterized by X-ray diffraction, nitrogen sorption and transmission electron microscopy. The results showed that the carbon material exhibited highly ordered mesoporous structure, with a high specific surface area of 1560 m2/g, and the pore size distributions of the sample are very narrow, centering at around 6 nm; and the platinum particles with sizes of less than 8 nm were highly distributed in the carbon matrix. The high specific surface area may be ascribed to plenty of small pores inside carbon walls caused by the removal of silica from the composites. Interaction between the Pt4+ and the resin caused the Pt species to be incorporated into the framework of the resin, which was self-assembled into an ordering structure under the direction of the surfactant. After being subjected to pyrolysis at a high temperature, the Pt4+ ions were gradually reduced to form Pt nanoparticles, which were strongly imbedded in the carbon substrate and thereby thermally stable. The removal of silica may result in the exposure of Pt nanoparticles, which render Pt nanoparticles to contact easily with reactant molecules.
Pyrolysis Kinetic of Basic Zinc Carbonate from Spent Catalyst and Preparation of Active ZnO by Microwave Heating
Authors: Zhang Ze Biao , Zhang Zheng Yong , Peng Jin Hui , Zhang Li Bo , Qu Wen Wen , Li Wei
Published: September 2009

The TG and DTG curves of self-made ZnO precursor were studied by the thermo-gravimetric analysis method in N2 atmosphere from 25°C to 650°C at the heating rate of 5, 10 and 15°C/min. The TG curve showed that the decomposition process started at about 150°C and finished at 300°C, in accordance with the temperature range of the decomposition from basic zinc carbonate to zinc oxide. The first level chemical reaction based on Coats-Redfern method was applied to estimate the activation energy of the decomposition. The correlation factor was about 0.99, and the calculated average activation energy was 33.89kJ/mol. Active zinc oxides were perpetrated by microwave heating at 350°C for 30min. Their composition and surface morphology were investigated by using scanning electron microscope and X-ray diffraction and its quality can reach the first-grade standard of HG/T2572-94.
Effect of Disbond Propagation on the Reflected Spectra of CFBG Sensors Embedded within the Bondline of Composite Bonded Joints
Authors: Guo Ya Lin , Ogin S.L. , Capell T.F. , Thorne A.M. , Reed G.T. , Wang Ying Song , Tjin S.C.
Published: September 2009

Chirped fiber Bragg grating (CFBG) sensors were embedded within the adhesive bondline of single-lap CFRP-GFRP bonded composite joints. The effect of disbond propagation (as a consequence of fatigue loading) on the reflected spectra from the CFBG sensor has been studied. As the disbond propagates, thermal strains generated during the bonding of the joint at elevated temperature are released and, as a consequence, a peak in the reflected spectra of the CFBG sensor can be seen. Using a transparent GFRP adherend, it has been possible to demonstrate that there is reasonable agreement between the position of the peak in the reflected spectrum and the disbond front position in the bonded joint.
Influence of Zinc-Zirconium Substitution on Magnetic Properties of Ba(ZnZr)xFe12-2xO19 Hexaferrite Prepared by the Molten Salt Method
Authors: Li Hai Feng , Gong Rong Zhou , Wang Xian , Fan Li Ren , He Gang , He Ming Zhong , Feng Ze Kun
Published: September 2009

M-type hexaferrites Ba(ZnZr)xFe12-2xO19 (x=0, 0.5, 1.0, 1.5) powders, have been synthesized by molten salt method, where x varies from 0 to 1.5 in steps of 0.5. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer(VSM) were used to analyze the structures and magnetic properties. The results showed that, the magnetoplumbite structures for all samples calcining at 1100°C have been formed. The magnetic hysteresis loop measurements of the hexagonal ferrites powders showed that the saturation magnetization (Ms), the remanent magnetization (Mr), and the coercitivity (Hc) of ferrites depend strongly on the chemical compositions of materials. The data showed that the max Hc was obtained when substitution of x=1.0 (Hc=63.9 Oe), while the best Ms was obtained when substitution of x=0.5 (Ms=54.02 emu/g). Zn and Zr substitutions greatly modified the magnetic properties of BaM hexaferrite.
Alkali-Activation Reactivity and Al Environment of Chemosynthetic Al2O3–2SiO2 Powders
Authors: Zheng Guang Jian , Cui Xue Min , Zhang Wei Peng , Tong Zhang Fa
Published: September 2009

In this study, pure Al2O3-2SiO2 powders for a geopolymer were prepared by a sol-gel method, alkali-activation tests and alkali-dissolvability of the powders were carried out, and structure of the powders and alkali-activated products was investigated by 29Si and 27Al MAS NMR and SEM. Results showed that higher alkali-activation reactivity (higher compressive strengths of alkali-activated products) appeared in the powders heat-treated between 600-800 °C and alkali-dissolvability trend was different from that of alkali-activation tests. There were clear correlations between microstructure of alkali-activated products and alkali-activation reactivity and Al environment of the powders. It was found that high strength was related to a dense, fine grained microstructure. Such a structure was found in the alkali-activated products synthesized with the powders with high 5-coordinated Al contents. In addition, the peaks attributed to 5-coordinated Al were strengthened with the rise of heat-treated temperature of the powders.
Synthesis, Characterization and Properties of a Novel Soluble Polyester Based on Fluorene
Authors: Zhou Yun , Liu C.M. , Dong Li Hua
Published: September 2009

Fluorene and its derivatives which have an aromatic biphenyl structure with wide energy gap in the backbone and high luminescent efficiency have been drawn much attention to materials chemists and device physicists. In this research, 9,9-Bis(methoxycarbonylethy)fluorene and fluorene-containing polyester were prepared and their chemical structure and properties were initially studied. Furthermore, It is found that this fluorene-containing polyester might be a promising candidate for electroluminescent materials due to its excellent luminescent properties, solubility, film-forming property and thermal stability.
Performance and Tribology of Polymer Matrix Friction Material Reinforced with Fibers
Authors: Chen Hai Yan
Published: September 2009

With development of traffic speed, friction materials were required more and more high, in this paper polymer matrix friction material reinforced with fibers was studied. The rigid modified phenolic resin and the soft rubber were mixed to form “polymer alloy”, which was the matrix of friction material. When the amount of resin-rubber blending system was 20~25%, the friction material had better friction performance. Carbon fiber had distinct effects on friction performance and mechanical properties. Friction material was a multicomponents composition, so the physical and chemical changes in material were complex. By TEM it was observed that “sea-island” blending system was obtained by mechanical mixing, in which rubber particles formed uniform distribution. By FTIR analysis it was known that because of the force-chemistry of polymer and time-temperature equivalence principle, resin chemically reacted with rubber during the mixing process.
Synthesis, Morphology and Photophysical Properties of Rod-Coil Copolymers
Authors: Yu Yang Yen , Chien Wen Chen , Hsu Chung Yi
Published: September 2009

The synthesis, morphology, and photophysical properties of poly[2,7-(9,9- dihexylfluorene)]-block-poly(2-vinyl pyridine) (PF-b-P2VP) with different coil lengths in mixed solvents of THF/methanol are reported. A flakes-like lamellar morphology is observed at a short coil length of PF-b-P2VP. As the coil length increases, a spherical and large compound micelle is formed. Upon further increase of the coil length, the morphological transformation from spherical micelles to long rod-like structures is observed. TGA results indicate a good thermal stability of the prepared copolymers. The spectra of optical absorption for the PF-b-P2VP in solution have a blue shift when the fraction of methanol in the mixed solvent increases. The present study shows that the significance of the rod/coil ratio and selective solvent content on the aggregate morphologies and photophysical properties of the rod-coil block copolymers.
Investigation on the Tap-Hole Clay under Thermal Processing
Authors: Yang Shi Ling , Zhang Jian Hua , Dong Ying , Sun Shi Bin , Cui Ping
Published: September 2009

Taking the waterless tap-hole clay in the 1750m3 blast furnace of Jinan Steel Corporation for example, thermal processing at temperatures ranging from 200°C to 1400°C has been performed. The authors systematically investigated the main features of the clay such as bending strength, compressive strength, porosity and density after thermal processing, the microstructure evolution of the clay with increasing temperature were also studied in brief. Research results provide theoretical information for the practical application of tap-hole clay in the blast furnace and are also helpful for understanding the possible property transition of the tap-hole clay in the tap-hole.
TEM Microstructural Investigation of 0.63C-12.7Cr Martensitic Stainless Steel during Various Tempering Treatments
Authors: Lin Yu Li , Lin Chih Chung , Liu An Chun , Lai Hong Jen
Published: September 2009

Microstructure of 0.63C-12.7Cr martensitic stainless steel during various tempering treatments was investigated in this study. Results demonstrate that finely distributed primary carbides were observed on 0.63C-12.7Cr martensitic stainless steel. The matrix phase of 0.63C-12.7Cr martensitic stainless steel when tempered below 500 °C was identified as martensite. However, the matrix structure when tempered at 500 °C and 600 °C was found containing of both ferrite and martensite. On carbide particles, mixed of M7C3 and M23C6 particles were observed on all specimens when tempered at 200-600 °C. The amount of M7C3 carbides was found decreased as the tempered temperature was increased.
Dependence of Aspect Ratio on1-3 Polymer/Cement Based Piezoelectric Composite Properties
Authors: Guo Li Li , Peng Ya Ping , Liao Shuang Shuang , Huang Shi Feng
Published: September 2009

Piezoelectric ceramic(lead niobium lithium zirconate titanate, P(LN)ZT), sulphoaluminate cement and polymer were used to fabricate 1-3 polymer/cement based piezoelectric composites by cut-filling technique. The influence of P(LN)ZT aspect ratio on the piezoelectric and dielectric properties of composites was investigated. The results show that as the P(LN)ZT aspect ratio increases, the piezoelectric strain factor d33 and relative dielectric factor εr decrease evidently, while the piezoelectric voltage factor g33 decreases slowly. The acoustic impedance Z is hardly influenced by the aspect ratio. At the same time, the influence of temperature on the dielectric properties of the composites was studied. The results show that with increasing the temperature at the frequency of 1kHz and 150 kHz, the dielectric factor εr exhibits the trend of increase. In the range of -40°C-110°C, the dielectric loss tanδ first increases slowly, but when exceeding the temperature of 80°C, it increases evidently. Comparing with P(LN)ZT piezoelectric ceramic, the vibration at thickness mode of 1-3 type piezoelectric composite is strengthened.
A Study on the Coating of Acupuncture Needle with Bioceramics to Improve Insulation Performance
Authors: Kim Man Tae , Chung Hyup Jae , Choi Gyu Seok , Kim Yong Bae , Rhee Kyong Yop
Published: September 2009

In this study, heat-acupuncture needle was coated with bioceramics by applying a plasma spray coating method to prevent a skin burn in the heat-acupuncture therapy. The effect of coating on the surface roughness of heat-acupuncture needle was investigated and the surface morphology was examined by scanning electron microscope (SEM). The effect of coating on the heat conduction of heat-acupuncture needle was also investigated. The results showed that the surface roughness of uncoated, Al2O3, and ZrO2 coated needle was 0.0675um, 8.568um, and 3.285um, respectively. The surface of ZrO2 coated needle was more uniform than that of Al2O3 coated needle. The results also showed that the heat conduction of heat-acupuncture needle was significantly affected by the bioceramic coating on the needle. Specifically, the maximum temperature of middle part of uncoated, Al2O3, and ZrO2 coated needle was 48°C, 38°C and 42°C, respectively.
Preparation of Cuprous Oxide from Industrial Leaching Liquid Using the Microwave Thermo-Ethanol Method
Authors: Lin Han Yu , Kuo Chao Yin , Wu Chung Hsin , Lin Tsai Hsung
Published: September 2009

This study investigates the use of the microwave thermo-ethanol method to recover cuprous oxide from waste liquid that contains heavy metals, formed by the leaching of acid from sludge of printed circuit boards. An XRD analysis yields main peaks of cuprous oxide 2θ = 36.45° and 42.35°. SEM analysis indicates that the cuprous oxide was octahedral when 0.1 M glucose, or a higher concentration, was added to the waste liquid. The purity of prepared powder of cuprous oxide was analyzed using an inductively coupled plasma-optical emission spectrometer (ICP-OES), and the purity of the prepared powder of cuprous oxide was found to exceed 70%. Accordingly, in this study, metallic resources were regenerated.
High Temperature Thermoelectric Properties of Oxide Ca2Co2O5
Authors: Li Guo Jing , Zhao Shu Jin , Mei Ao , Lan Jin Le , Lin Yuan Hua
Published: September 2009

Ca2Co2O5 ceramic powders were synthesized by the coprecipitation method and consolidated by spark plasma sintering (SPS) technique.The observation by the SEM indicated that the ceramics body showed fine and layer microstructure.The density of the body increased with an increase of the fritting temperature.XRD patterns showed that the ceramics sample exhibits inpure phase with increasing the sintering temperayure to 850°C and that the grain was preferentially oriented.The electrical conductivity was reduce and the Seebeck coefficient slightly increased with an increase of the sintering temperature.As a result,the thermoelectric properties of the sample prepared by SPS at 800 °C for 5 min was better than the sample prepared by SPS at 750 °C for 5 min at high temperature.The sample treated by the SPS process under the condition of 800 °C,40 MPa and 5 min showed the maximum power factor (PF) of 3.85×10-4W∙m-1∙K-2 at 923 K.
Investigation on the Sound Absorption Properties of MPA/MR
Authors: Ma Yan Hong , Hong Jie , Zhu Bin , Wang Hong
Published: September 2009

This paper introduces a sound absorption structure named as MPA/MR which is a combination of the MPA and Metal Rubber (MR) material. On the basis of Rayleigh model and sound propagation theory in pipe, according to the acoustoelectric analogy method, the theoretical acoustic model of MPA/MR is established, and the formula of absorption coefficient is derived. The multi-function standing wave tube with two microphones was used to obtain acoustic characteristics of MPA/MR experimentally, and the effects of the parameters were analyzed as well. The investigation indicates that MPA/MR can be applied with a broad range of application prospects.
Effects of Aluminizing on the High Temperature Oxidation Behavior of High Silicon Cast Iron
Authors: Lin Meng Bin , Wang Chaur Jeng
Published: September 2009

In this study, the aluminizing of high silicon cast iron by hot-dipping in pure Al melt was performed and their high temperature oxidation behaviour was tested at 750 °C for virous exposure time. After high temperature oxidation tests, the microstructure analysis of all samples were investigated by means of metallographical examination, scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectrometer (EDS) and X-ray diffractometry (XRD).The results showed that the coating layers consisted of three layer, in the sequence of Al, Fe-Al and Si-rich layers from external topcoat to substrate. Nodules graphite had a blocking effect to retard the outward diffusion of Fe atoms and impeded the growth of Fe2Al5 in C-axis. Eventually, the cast iron substrate was oxidized directly by oxygen penetration via the greater cracks and pores to form Fe oxide nodules after 750 °C oxidation for 48h.
Fabrication and Electric Properties of SrTiO3-δ/Nb-SrTiO3 Heterjunction
Authors: Ni Mu Cui , Wang Yan Hong , Li Hai Ying , Liu Jia Yi , Wang Zhi Jun , Li Shou Chun
Published: September 2009

SrTiO3- (STO) thin film has been deposited epitaxially on the (100) oriented, 0.1 wt % Nb-doped SrTiO3 (NSTO) substrate using the pulsed laser deposition technique. The current-voltage (I-V) characteristics of STO/NSTO heterojunction at various temperatures had been measured. A rectifying behavior similar to conventional diodes was observed. For the forward bias, the conduction mechanism changes from Ohmic-like for the low bias voltages to space charge limited current for the high bias voltages. The results were explained by considering the band structures of the heterojunction and the role of space charge layer formed at the interface between STO and NSTO. Our results demonstrate that the interface formed between two oxide materials plays an important role on transport characters of the system and can lead to some potential applications in future microelectronic devices based on combination of two perovskite oxide materials.