bluuebunny/crossref_metadata_2025 huggingface dataset:
Recovery and Separation of Si and SiC in Wire Cutting Waste Slurry from Photovoltaic Silicon
Authors: Wang Yan Xiang , Jiang Chao , Liang Hua Yin
Published: June 2012

Abstract. The Si and SiC in wire cutting waste slurry from photovoltaic silicon were recovery and separation by froth floatation in this paper, and the lauryl amine and sodium hamates were used as collector and flocculants, respectively. The effects of collector concentration, inhibitor species, and solution temperature and pH value on separation efficiency were investigated. The morphology of collected solid was characterized by SEM.The phase composition of collected solid was characterized by XRD. Laser particle seizer was used to study the particle size distribution. The results showed that temperature had little effect on the flotation efficiency. When pH value was 7, the lauryl amine adapts to neutral environment and the collecting effect of collector was the best, and cellulose was considered to be the best inhibitors in four different inhibitors. When volume fraction of lauryl amine, sodium humate flocculant, cellulose inhibitor, and temperature and pH value were 0.16%, 0.16%, 0.25‰, 30°C and 7, respectively, the solid collecting rate and collected SiC purity were respectively 51.94% and 94.7%.
A Study on Electrical Resistivity of BaO–CaO–SiO2–Al2O3 Seal Glass Used in Solid Oxide Electrolytic Cell (SOEC)
Authors: Hao Jie , Deng Chang Sheng , Zan Qing Feng , Xu Jing Ming
Published: June 2012

The electrical resistivty (R) of BaO–CaO–SiO2–Al2O3 (BCSA) based glass, which was used in SOEC, was measured by impedance analyzer from room temperature to sealing temperature, and it was founded that electrical resistivity of all seal glass decreases with temperature. When temperature is lower than the soften temperature of glass, the electrical resistivity of all seal glass was no less than 107Ω∙cm. At 850°C, the resistivity of the 16BaO–16CaO–42SiO2–8Al2O3 glass (G1) reached 4.40×106Ω∙cm, and even at the sealing temperature, their resistivity was still above 105-106Ω∙cm. With the decrease of ratio of Si/B from 3 to 1, the electrical resistivity of glass decreased from 4.40×106Ω∙cm to 8.96×104Ω∙cm. The electrical resistivity of glass in BCSA system could be significantly affected by B2O3 and alkaline earth oxides. The results show that the electrical resistivity of glass was improved with the increasing of non-bridging oxygen and the average field strength. All glasses can be used as sealants at high temperature with no electrical shunting in SOEC.
Mixtures of TiO2·0.2H2O and LiFePO4 as Li-ion Battery Cathode Materials
Authors: Hong Zi Jian , Tang Zi Long , Xu Yu Xing , Hong Ye , Tan Ao , Zhang Zhong Tai
Published: June 2012

Mixtures of TiO2•0.2H2O (HTO) and LiFePO4 were prepared via three main composite methods: 2-2 series model, 2-2 parallel model and 3-3 model. HTO had been reported to exhibit high specific capacity (~200 mAh/g at 1 C) as well as excellent cycle property, whereas its voltage plateau was too low (about 1.7 V vs. Li) as a cathode material. LiFePO4 was a promising cathode material for its high voltage plateau (about 3.4 V vs. Li), low cost and high specific capacity (~150 mAh/g at 1 C). However, because of its low conductivity, the rate property as well as cycle property was limited. The mixtures of HTO and LiFePO4 were considered to combine the advantages of both materials. By comparison, the 2-2 parallel model excelled in both rate property and cycle property. Its specific capacity can reach as high as 220 mAh/g with a high specific energy of 450 Wh/Kg at 0.1 C. Even after cycled 200 times at 2 C, the capacity can still be higher than 100 mAh/g. CV measurements and a combined constant current and constant voltage tests supported a two plateaus process for 2-2 parallel model. The charge-discharge voltage gap increased for the 2-2 parallel composites, which was supposed to be related to the interface. In general, the specific energy was much higher than HTO while the specific capacity as well as cycle property was much better than LiFePO4 as a cathode material. .
Application of Electrochemical Impedance Spectroscopy in Organic Solar Cells with Vertically Aligned TiO2 Nanorod Arrays as Buffer Layer
Authors: Zhang Yong Chang , Jiao Xing Jian , Zhou Chen , Shen He Ping , Hao Feng , Hotozuka Kozue , Lin Hong
Published: June 2012

Single-crystal TiO2 nanorod film was synthesized directly on FTO substrates with various lengths by changing the hydrothermal growth parameters including growth time and growth temperature. The obtained nanorod arrays were incorporated in organic solar cells as buffer layer instead of PEDOT: PSS. Results showed that devices assembled with TiO2 nanorods film of 200 nm in length exhibited a lower open-circuit voltage but a significantly higher short-circuit current density compared to those of normal FTO/PEDOT: PSS/P3HT: PCBM/Al structure with a comparable active layer thickness. Overall the power conversion efficiency was boosted by two-fold. Electrochemical impedance spectroscopy (EIS) analyses revealed that the improvement in the photovoltaic performance was induced by the inhibited recombination and consequently enhanced electron lifetime.
Application of Three-Dimensional ZnO Inverse Photonic Crystal in Dye-Sensitized Solar Cells
Authors: Gao Jing Jing , Li Bo , Liu Zhen Dong , Jiao Xing Jian , Zhou Ji , Lin Hong , Li Long Tu
Published: June 2012

Because of the features of photonic localization in photonic bandgap(PBG), the photonic crystals can be coupled to DSSC to increase the conversion efficiency. In this paper, through exploring the preparation of large inverse opal structure of ZnO, we attempt to apply the photonic crystals to the Dye-Sensitized Solar Cells (DSSC) to improve its efficiency. The colloidal crystal template is prepared by self-assembled on FTO substrates, and three-dimensional ZnO inverse opal is synthesized via an electrochemical deposition method in zinc nitrate solution. Then we study the inflations of its surface morphology and photonic bandgap on the solar cell’s photoelectric conversion efficiency.
The Thermoelectric Performance Enhancement of N-Type BiTeSe Alloys by Addition of ZnAlO
Authors: Zhang Ting , Jiang Jun , Yang Sheng Hui , Zhai Yong Biao , Xu Gao Jie
Published: June 2012

A series of n-type BiTeSe/ZnAlO composites were prepared by zone melting method. Thermoelectric properties, including the electrical conductivity σ, Seebeck coefficient α and thermal conductivity κ, were measured in the temperature range of 300-550K. Results show that the electrical properties have been slightly lowered due to the reduced carrier concentration by ZnAlO addition. However, the low-temperature-shifted peak α, resulting from the prematurely happened intrinsic excitation, have shifted peak ZT to lower temperatures. As a result, the ZT values at 300 K were significantly enhanced for BiTeSe/ZnAlO composites compared to that of BiTeSe, making more attractive for cooling applications at ambient temperature.
Solvothermal Growth of Cobalt Oxide Hexagon Nanodiscs
Authors: Wang Long Fan , Peng Zhi Jian , Lei Ming , Fu Xiu Li
Published: June 2012

In this work, cobalt oxide nanodiscs were successfully fabricated through a simple solvothermal synthesis method. The obtained cobalt hydroxide nanodiscs are of single-crystalline hexagonal structure with well-defed nanodiscs were found to have very weak magnetic properties, much weaker than its bulk cobalt oxide counterparts, which might find interesting application in special electromagnetism devices.
Photocatalytic Enhancement in Methylene Blue Degradation of TiO2 Photocatalysts via Graphene Hybridization
Authors: Zhou Feng , Fu Ying Qing , Wan Xin
Published: June 2012

A facile route was demonstrated to obtain an efficient graphene-hybridized TiO2 photocatalyst. The photodegradation results of Methylene Blue over graphene hybridized with TiO2 showed that the photocatalytic activity could be significantly enhanced under UV light irradiation. The structure between TiO2 and graphene as well as its effect on the photocatalytic activity were systematically investigated. The mechanism of the enhanced photocatalytic activity is based to the high migration efficiency and the inhibition of recombination of photoinduced electron-hole pairs. The graphene hydridization is proven to be a promising approach to develop highly efficient and stable photocatalysts under UV light irradiation.
Pores Formation Mechanism of Undoped TiO2 Ceramics
Authors: Yuan Jun , Yan Ji Kang , Gan Guo You , Du Jing Hong , Yi Jian Hong
Published: June 2012

Formation mechanism of pores in undoped TiO2 ceramics was investigated through defects chemistry and materials testing methods. The undoped TiO2 ceramics samples were prepared from anatase TiO2 powders by a traditional solid-state sintering method. Microstructure, chemistry composition and ionic valence of undoped TiO2 ceramics were by SEM, EDS and XPS. Formation mechanism of pores was discussed by combination defect chemistry with materials structure measurement. The results show that there exist trivalence Titanium ion (Ti 3+) and grain boundaries absorbed oxygen in undoped TiO2 ceramics samples. Both content of absorbed oxygen in grain boundaries and Ti 3+ concentration increase with sintering temperature increasing. There are much gas pores in grains and grain boundarties of undoped TiO2 ceramics samples. The gas pores are mainly originated from lattice oxygen volatilization and oxygen vacancies segregation during high-temperature sintering.
Super-Hydrophilic Lu3+-Doped TiO2 Photocatalysts for Self-Cleaning Applications
Authors: Xu Wen Yuan , Meng Li Na , Yang Chuo , Huang Guo Lin
Published: June 2012

The self-cleaning glasses can be realized by coating the photoinduced super-hydrophilic Lu3+-doped TiO2 thin films via innovative ultrasonic-sol-gel route. The composition, structure and performance of the as-obtained material were characterized by XRD, SEM, FT-IR and UV-vis. The super-hydrophilicity is assessed by contact angle measurement. Photocatalytic properties of these films are evaluated by degradation of methyl orange under UV irradiation. The results indicate that the crystalline phase composition of Lu3+ doped TiO2 films is anatase, and the particle size is from 6 to 15 nm. In addition, Lu3+ doping can bring the red shift of the optical absorption edge of TiO2. The films exhibit excellent super-hydrophilicity and photocatalytic properties after UV radiation and the hydrophilicity can maintain for a long time in the dark place, which favors greatly the self-cleaning function of the films.
Effect of Testing Conditions on ZnFe2O4 Film Photoelectrocatalytic Properties
Authors: Jin Jian Guo , Hou Gui Qin , Zhang Wen Li
Published: June 2012

The nano-sized ZnFe2O4 films were prepared by Sol-gel process on the conducting electricity glass, and the influence factors of the samples’ photoelectron-catalytic performances was investigated, such as the pole materials, the distance between electrodes, the voltage and the light source etc. The results indicated that, the photoelectron-catalytic effect was best when ZnFe2O4 film as the anode and the conductive glass as the cathode, which showed that the main reaction was the photo-generated holes. When the voltage was constant, there was an optimal value of plate spacing. With the plate distance increasing, the effective contact probability of the photon-generated carrier and the degradation was increased. But the plate spacing was too wider, the moving resistance of photon-generated carrier became higher, so as to the degradation rate decreased. The degradation rates of the films showed undulate increase with the voltage increasing in the different kinds light resources conditions.
ZrC Oxidization Mechanism in Air
Authors: Zhang Yu Wei , Zhang Jin Yong , Xie Jing Jing , Fu Zheng Yi
Published: June 2012

The ZrC oxidization mechanism in air was carefully investigated by the phase composition and grain morphology through DSC, X-ray diffraction and SEM respectively at different temperature. It was found that the oxidization of ZrC start at about 400°C by oxygen atom entering the interstitial sites to substitute part of Carbon. Zr2O and ZrO2can be formed at a temperature of about 600°C and 1000°Crespectively. And ZrC will completely transfer to ZrO2at 1000°C for 5hrs. No obvious grain morphology change was found under 600°C.
Effects of Annealing Temperature on Morphology and Dielectric Property of BiFeO3 Films
Authors: Zhang Li Li , Tan Guo Qiang , Cheng Meng , Ren Hui Jun , Xia Ao
Published: June 2012

Fe(NO3)3•9H2O and Bi(NO3)3•5H2O were used as raw materials. BiFeO3 thin films were prepared by sol-gel method. The effects of annealing temperatures on the morphology and dielectric property of the thin films were studied. XRD results show that the multi-crystal thin films with pure phase are obtained when annealed at 500°C and 550°C. But annealing at 580°C will lead to the appearance of Bi2.46Fe5O12 phase.AFM images show that as the increase of annealing temperatures the surface toughness of the thin film is decreased, but the surface undulation of the thin films is decreased gradually. Within the frequency range of 1KHz~1MHz, the dielectric constant of BiFeO3 thin films is kept over 125 and it does not change very much from 500°C to 580°C. Annealed at 550°C, the BiFeO3 thin films with the lower loss are obtained. At 1MHz, the dielectric loss is 0.12.
Fabrication and Mechanical Properties of Chitosan-Montmorillonite Nano-Composite
Authors: Shou Z.J. , Le H.R. , Qu S.Y. , Rothwell R.A. , Mackay R.E.
Published: June 2012

Chitosan has found various applications in gastrointestinal stent, biomedical implants as well as an effective absorbent in waste water treatment. However, the material suffers from low strength and large shrinkage upon dehydration. The current project is aimed to develop a process to fabricate chitosan composites with the addition of functionalised montmorillonite nanoparticles and to examine the effect of ceramic content on the mechanical behavior of the composites. This paper describes the fabrication of chitosan with montmorrillonite composites and the mechanical testing of the samples and the mechanical behaviour of the composites, as well as the observations of the microstructure. The effects of composition and microstructure on the mechanical properties of the composite are investigated. The results indicate that the nanoparticles are dispersed uniformly in the matrix up to 40wt% using high speed homogeniser. The elastic modulus increases monotonically with the addition of nanoparticles, but the fracture strength drops due to the defects introduced by the nanoparticles.
Relative Translucency of Dental Lithium Disilicate Ceramic Restorations
Authors: Shao Long Quan , Sun Ting , Gan Yun Na , Liu Qi , Yi Yuan Fu , Deng Bin , Wen Ning
Published: June 2012

Abstract. This study investigated the relative translucency of IPS E.max core-veneer combinations of different colors at a clinically appropriate thickness. Core specimens (n=5) of IPS E.max were produced and veneered with IPS E.max veneering porcelain to a final dimension (13 mm in diameter, 1.5mm in thickness). Luminous reflectance was measured three times each specimen with a calibrated spectrophotomete. Contrast ratios were measured from the luminous reflectance(Y) of the tested specimens with a black (Yb) and a white background (Yw). Contrast ratios ranged from 0.798-0.818 for LT core-veneer combinations, 0.831-0.845 for MO core-veneer combinations, 0.929-0.941 for HO core-veneer combinations. There were no significant difference in contrast ratios of core-veneer combinations of the same series (P>0.05). Contrast ratios of LT, HO, MO core-veneer specimens were significantly different (P<0.05). Luminosity and chroma are not related to the relative translucency of core-veneer specimens. LT core-veneer combinations exhibited highest relative translucency, followed by MO and HO core-veneer combinations.
Masking Ability of IPS e.max ALL-Ceramics System of HO Series
Authors: Zhou Shan Yu , Shao Long Quan , Wang Lin Lin , Yi Yuan Fu , Deng Bin , Wen Ning
Published: June 2012

To evaluate the masking ability of IPS e.max all-ceramics system of HO series. IPS e.max Press HO ingots were fabricated into twenty cylindrical specimens (n=5) with the diameter of 13mm and four different thinknesses (0.4mm, 0.6mm, 0.8mm, 1.0mm). All specimens after veneered, gazed and cemented to metal substrate disks (thickness 3mm, diameter 13mm) were measured on both the white background and metal substrate disks background using a spectrophotometer and values of L, a and b were calculated to compare color differences among four groups. Meanwhile ΔE with the preselected required color (A2 color) were calculated. ΔE<1.5 was considered a clinically acceptable color match. In the 0.4mm thickness specimens group, the values of L, a and b significantly increased (-1.36±0.05, -0.15±0.06, -1.46±0.02, respectively) between the white background and abutment background. But there were no significant color differences in the other three groups (P<0.05). In the 0.6mm and 0.8mm thicknesses specimens groups, the color difference values (0.71±0.04, 1.14±0.06, respectively) with A2 color were less than the defined value. Thus the cylindrical specimens with the thickness of 0.6mm, 0.8mm and 1.0mm could mask the metal substrate disks background sufficiently and the thickness of 0.6mm and 0.8mm had an acceptable color match compared with the target color. IPS e.max all-ceramics system of HO series can produce clinically acceptable color match and have the capacity to mask a dark background such as a dark tooth or core buildup material.
Preparation of Pigmented Glass for Infiltration and Investigation of its Physical and Mechanical Properties
Authors: Lu Huai Xiu , Yi Yuan Fu , Deng Bin , Shao Long Quan , Zhao Li Sheng , Shi Guang , Lu Rong Jian , Wen Ning
Published: June 2012

Aim To explore pigmented glass for infiltration and investigate its physical and mechanical properties. Methods The pigmented glass was prepared by melting glass components in an alumina crucible at 1400°C for 2h. The thermal properties were tested using a Setaram-TGDTA 92 analyzer; three point bending strength and fracture toughness were also tested; the microstructure of the glass was studied using a scanning electron microscope. Results The thermal expansion coefficient over the range 20–600 °C was 6.2 × 10-6 °C -1, Tg was about 690 °C, the density, bending strength, fracture toughness and Vickers hardness were 2.23 g/cm3, 118 MPa, 1.22 MPam1/2, and 7.4 GPa respectively. Conclusion The pigments have no detrimental effects on the physical and mechanical properties; thus the pigmented glass for infiltration has favorable physical and mechanical properties and also good compatibility with presintered porous alumina.
Improving Bioactivity of Porous β-TCP Ceramics by Forming Bone-Like Apatite Layer on the Surfaces of Pore Walls
Authors: Zan Qing Feng , Zhuang Yuan , Dong Li Min , Wang Chen , Wen Ning , Xu Guo Hua
Published: June 2012

Bone tissue engineering provides a new way to repair the bone defect in orthopaedics. The scaffolds, porous materials with excellent biocompatibility, bioactivity and biodegradability, play an important role in bone tissue engineering. Furthermore, the bioactivity of the pore interior surfaces is very important for cell attachment, differentiation and growth, as well as new bone tissue ingrowth into pores. In this paper, β-TCP was selected as materials of scaffolds, and its bioactivity was improved by activating the interior surfaces of pore walls. The porous β-TCP scaffolds with about 50~300μm of pore size and above 80% of porosity were obtained by 3D-gel-laminated processing. Their surfaces of the scaffolds were easily covered by a low crystallized bone-like apatite layer, which determined by XRD and FTIR, after immersing in 1.5SBF solution following pre-treatment by NaOH solution. MTT and ALP assays were performed after cells cultured on the porous scaffolds with bone-like structure, and the results showed higher proliferation rate and differentiation level than that on the scaffolds without treatment, which indicated that the porous β-TCP scaffolds with bone-like apatite layer on surfaces of pore walls possess higher bioactivity. Therefore, the bioactivity of tissue engineering scaffolds could be improved by deposited bone-like apatite layer on their surfaces.
TiO2 Whisker Prepared with Tataniferous Blast-Furnance
Authors: Zhang Wen Li , Gao Sui Jing , Zhao Ying Na
Published: June 2012

Using titaniferous blast-furnace slag (44-70 wt %), quartz, boric acid, and borax as the main raw materials, composition selecting in the phase-separation region of the Na2O-CaO-Al2O3-B2O3 -SiO2-TiO2 system, the basic glasses were prepared through mixed batches and melted at 1200 oC, then TiO2 whiskers could be achieved by heat-treatment the glass samples. The phase and morphology of samples were analyzed by XRD and SEM. The results indicated: when the composition of samples were selected in the phase-separation region and the ratio of SiO2/ B2O3 was between 1.64-1.87, at 850 °C heat-treatment, the diameter of whiskers was about 0.5μ~1μ and the length-diameter ratio was more than 50.
Effect of Cd2+ Concentration on the CdS Crystallites Prepared by Microwave Hydrothermal Process
Authors: Huang Jian Feng , Zhang Qin Feng , Hu Bao Yun , Cao Li Yun , Wu Jian Peng
Published: June 2012

Cadmium sulphide (CdS) crystallites were successfully prepared by a microwave hydrothermal (M–H) process using cadmium chloride (CdCl2·H2O) and sodium thiosulfate (Na2S2O3·5H2O) as source material with different Cd2+ concentration. The phase, composition, morphology and optical property of the obtained crystallites were characterized by X–ray diffraction (XRD), field–emission scanning electron microscopy (FE–SEM), transmission electron microscopy (TEM) and ultraviolet–visible spectrophotometer (UV–Vis). Results show that the crystalline structure of the prepared CdS crystallites changes regularly with the increase of Cd2+ concentration and the corresponding morphology of CdS crystallites transforms from tetrahedron to quasi-sphere. The quasi-spherical CdS is derived from the nanoparticles-assembly behavior. And with the increase of Cd2+ concentration, the decrease in CdS crystallite size is observed. Obvious blue–shift is detected in the UV–Vis absorption when Cd2+ concentration reaches 0.60 mol/L.
Synthesis of In2Se3/CuSe Composite Powder by Solvothermal Method
Authors: Gao J. , Zou Z.G. , Long F. , Xie C.Y. , Chi S.S.
Published: June 2012

The In2Se3/CuSe composite powders with the size in the range of 2-8µm for solar cell were successfully synthesized via using relatively simple solvothermal method at atmospheric pressure by the reaction between InCI3.4H2O, CuCI2.2H2O and Selenious acid and hydrazine hydrate in ethylene glycol.The influences of reaction temperature, reaction time, concentration of solution on the phase and morphology of In2Se3/CuSe composite powders were investigated. The phase and morphology of the products hSubscript textave been well studied by X-ray diffraction (XRD)and scanning electron microscope (SSubscript textEM) techniques.The study revealed that under the conditions of solvothermal method at atmospheric pressure, relative pure In2Se3 and CuSe powder were synthesized at temperatures of 160°C and 100°C respectively. The In2Se3/CuSe of irregular flake composite powders with the average size of 2-8µm had been obtained.The morphology of the products can be controlled by adding different kinds of surfactants such as PVP (Polyvinylpyrrolidone), CTAB (Hexadecyl trimethyl ammonium Bromide) and so on.
Synthesis of LiV3O8 Crystallites via an Improved Citric Acid Assisted Sol-Gel Method
Authors: Wang Dun Qiang , Cao Li Yun , Huang Jian Feng , Wu Jian Peng
Published: June 2012

Lithium trivanadate (LiV3O8) powders have many attractive characteristics such as high specific energy density, good rate capacity and long cycle life due to their unique crystal structure and outstanding structure stability as cathode material for rechargeable lithium batteries. LiV3O8 crystallites were synthesized under different conditions via a combined ultrasonic irradiation and sol-gel method. The as-prepared LiV3O8 powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) absorption spectra. The thermal decomposition process was investigated using thermogravimetric (TG) and differential scanning calorimetry (DSC). The effects of molar ratios of metal ion/citric acid and calcinations temperature on phases and microstructure of the powders were investigated. Results indicate that calcinations temperatures have significant influence on the particle morphology, particle size and particle size distribution of the powders. The pure and rod-like LiV3O8 powders with an average size of 0.2-1 μm are obtained at 350 and 400 °C. With the increase of calcinations temperature, the powders exhibit preferred growth orientation along (100) planes. The crystallites obtained at 550 and 600 °C are composed by LiV3O8 with a small amount of Li0.3V2O5 phase, both of which exhibit tabular morphologies with an average size of 2-10 μm.
Effect of pH Value on Preparation of La2CuO4 Microcrystallites Synthesized by Sol-Gel Process
Authors: Li Yi Feng , Huang Jian Feng , Cao Li Yun , Wu Jian Peng
Published: June 2012

La2CuO4 crystallites were prepared via a sol-gel process using lanthanum nitrate and cupric nitrate as raw materials, distilled water as solvent, citric acid as complexing agent and ammonia to control the pH value. The as-prepared La2CuO4 crystallites were characterized by XRD, FESEM, TEM and UV-Vis spectra. Results show that the crystallization property of La2CuO4 crystallites increases firstly and then decreases with increasing of the solution pH value from 1.0 to 2.5, but all of the samples exhibit single sphere-like morphology. It is found that when the solution pH value is controlled at 2.0, the grains display uniform distribution and the size ranges from 100nm to120nm after sintering at 600°C for 2 hours. The optical band gap of the as-prepared La2CuO4 crystallites is calculated to be 1.38eV.
Fabrication and Characterization of ZrO2 Hollow Spheres
Authors: Liu Kai , Li Sa , Wang Chang An
Published: June 2012

Zirconium dioxide hollow microspheres were prepared using carbonaceous polysaccharide microspheres as a template through a heterogeneously nucleating wrapping technique. Firstly, carbonaceous microspheres wrapped by ZrO2 were synthesized, and then the obtained precursor was calcinated at 800°C for 2 hours to remove the template. Based on SEM, TEM and EDS analysis, the microstructure, composition and thermal decomposition process of the precursor as well as the final products were investigated. The formation mechanisms of the core-shell structure precursor and the hollow microspheres were also discussed.
Effect of Dispersant on the Measurement of Particle Size Distribution of Titanium Dioxide
Authors: Shen Li , Hu Jin , Wu Da Ping
Published: June 2012

As anionic surfactant, a commercial salt of lauryl sodium sulfate was used. The effects of different amounts of dispersant on the measurement of particle size distribution between two titanium dioxide powders (anatase and rutile) in aqueous media were discussed. Diluted aqueous suspensions were characterized in terms of particle size distribution and zeta potential. The results demonstrate that the measurement of particle size distribution strongly depends on the amounts of dispersant. The amounts of dispersant have a significant effect on the behavior of the rutile-TiO2 particles. The particle size first decreases significantly with an increase in the amounts of dispersant and then lesser increases with a further increase in the amounts of dispersant. The tendency show significant differences between two particles.
Preparation of ZrO2 Micro Beads by Sol-Gel Method
Authors: Hao S.C. , Zhao X.Y. , Ma J.T. , Zhou X.W. , Liang T.X , Fu X.M. , Lu Z.M. , Guo W.L.
Published: June 2012

ZrO2 micro beads are widely used as abrasive media in many areas. This paper introduces a sol-gel process for preparation of ZrO2 micro beads. First, zirconium nitrate solution and urea were mixed to prepare the sol, then the sol was converted to uniform droplets by vibrating dispersion method. The droplets were emitted from the nozzles into an ammonia solution. Along the way from the nozzle to ammonia solution, the liquid droplets first form spherical shape by their surface tension in air, and were then surface-hardened through ammonia gas. The microspheres complete gelation in the ammonia solution. The gel spheres were treated successively by aging, washing, drying, calcination and sintering to yield ZrO2 ceramic micro beads. The crystal structure of micro beads was examined by X-ray diffraction (XRD). The microstructure of the micro beads was observed by scanning electron microscopy (SEM). The results indicate that the sol-gel process can be used to prepare ZrO2 ceramic micro beads with good sphericity and uniform distribution of diameter.
Preparation and Properties of Rigid Polyurethane Foams Reinforced by Sepiolite Minerals Nanofibers
Authors: Wang Fei , Liang Jin Sheng , Tang Qing Guo
Published: June 2012

Rigid polyurethane foams were prepared using sepiolite nanofibers as main functional fillers. The effect of sepiolite nanofibers on the properties of polyurethane foams was studied systematically. Through characterization by scanning electron microscope, X-ray diffraction and property test, it was found that the thermal insulation effect can be maintained, and the mechanical properties can be improved due to the good interfacial bond between sepiolite nanofibers and rigid polyurethane foams.
Preparation and Characterization of Coated Carbon Black Pigment
Authors: Wang Xia , Chang Qi Bing , Bao Qi Fu , Zhang Xiao Zhen
Published: June 2012

Black pigment is an important pigment in the ceramic decoration. The traditional black pigment is spinel type matter containing Co, Fe or Cr elements. Carbon black is the best black pigment and is nontoxic. However, carbon black is oxygenated in the ceramic sintering process at atmosphere. Carbon black enclosed in the crystal latter of ZrSiO4 was reported. However, the content of carbon black is little which decreases the color generation. Carbon black coated with SiO2 was prepared by sol-gel method using combustion method using SiO2 sol and black ink as raw materials. The obtained black pigmenSubscript textt was characterized by XRD, TEM and ultraviolet-visible spectrophotometer. The results show that the black pigment does not change its color after calcinations at 1300 °C at atmosphere implying the carbon black is coated completely with SiO2.
Reaction Formed SiC Prepared by Room Temperature Freezing Casting
Authors: Hu Chuan Qi , Wang Hua , Liu Hai Lin , Huo Yan Li , Tang Jie , Chen Yu Feng
Published: June 2012

The porous carbon preforms with fine pore structure has been successfully fabricated by room temperature freezing casting, and the reaction formed SiC with fine mechanical property has prepared successfully by liquid silicon infiltration process. Charcoal powder was used as carbon resource, camphene was used as sublimate vehicle, methyl cellulose was used as pore maker and bonder. The result shows that the homogeneity of the porous carbon preform has been improved largely by adding methyl cellulose ,and the defects of reaction formed silicon carbide has reduced largely also. The density, average flexural strength and Weibull modulus of the best reaction formed silicon carbide prepared in this paper is 2.86 g/cm3, 430.75MPa and 9.29 respectively.
Synthesis of Ti(C,N) Powder via CRN Method from Rutile/Carbon Mixtures
Authors: Chen Kai , Huang Zhao Hui , Fang Ming Hao , Liu Yan Gai , Ouyang Xin
Published: June 2012

Ti(C,N) powder was prepared via carbothermal reduction nitridation (CRN) using rutile and carbon black as the raw material. The phase evolution and the reaction mechanism during the CRN synthesis of Ti(C,N) were investigated, and the effect of reaction temperature and C/TiO2molar ratio on the phase composition and x value in TiC1–xNxwas analyzed. The XRD and SEM results show that: Ti(C,N) powder was synthesized at 1500°C for 4h with the C/TiO2molar ratio of 2.2, under the nitrogen pressure of 0.2MPa. Irregular granular structure and the growth stripes were observed in the final products. The growth of Ti(C,N) grains in CRN process was followed by the gas-solid mechanism.The phase compositions of the products were quite dependent on the reaction temperature and the C/TiO2molar ratio. The TiN content in Ti(C,N) decreased with the increase of reaction temperature. TiC1–xNxpowder with different x values can be synthesized by optimizing the experiment conditions including the synthesis temperature and the C/TiO2molar ratio.
Preparation of Thin Cordierite Sheets by Aqueous Tape Casting
Authors: Wang Shao Hong , Niu Chang Lei , Hou Zhao Xia , Lu Hao Ran , Xue Zhao Lu , Wang Hao , Wang Cai
Published: June 2012

Aqueous tape casting process was used to prepare the thin cordierite sheets, the influences of dispersant (PAAS), the rate of plasticizer (PEG),and binder (PVA),content (R) and drying temperature on the tape casting process were investigated, the sintering character of the sheets were studied after drying. It was showed that when the content of PAAS was 1wt%, the slurries were stable uniform and the shear thinning was reversible. The green sheets with the thickness of 177μm showed good flexibility, lubricious surface and compact microstructure when R was 0.7 and the drying temperature was 25°C. A compact α-cordierite sheet was obtained at 1000°Csintering for 2h.
Microstructures and Properties of Solidified TiC-TiB2 Ceramic Composites with Increasing Cr Metallic Binder Prepared by Combustion Synthesis in High-Gravity Field
Authors: Liu Liang Xiang , Zhang Long , Zhao Zhong Min , Wang Min Quan
Published: June 2012

By increasing addition amount of (CrO3 + Al) subsystem in (B4C + Ti) system, the solidified TiC-TiB2 composites with a series of mass fraction of Cr binder were achieved by combustion synthesis in high-gravity field. The microstructures of the solidified ceramics presented a number of fine TiB2 platelets embedded in TiC grains, Cr-Ti alloy or between TiC grains and Cr-Ti alloy. The increased Cr binder in the ceramic not only brought about the enhanced densification of the ceramic due to fill-up of Cr-Ti liquid in shrinkage cavities between solidified TiC and TiB2 phases, but more importantly made fine-grained even ultrafine-grained microstructure achieved because of the accelerated nucleation and the decelerated growth of TiB2 at initial stage of material solidification. As a result of the achievement of fine-grained even ultrafine-grained microstructure along with the enhanced toughneing mechanisms contributed by the refined TiB2 platelets and the increased plastic phases of Cr-Ti alloy, the solifidied TiC-TiB2 composite containing 20.7 % Cr binder presented the maximun values of 1045 ± 25 MPa and 21.5 ± 1.6 MPa • m 0.5, simultaneously, in flexural strength and fracture toughness along with the moderate hardness of 17.5 ± 2.2 GPa.
Fabrication of Bulk Ceramics by High-Gravity Combustion Synthesis
Authors: Liu Guang Hua , Li Jiang Tao , Yang Zeng Chao
Published: June 2012

Both single-phase and multiphase bulk ceramics were prepared by high-gravity combustion synthesis via melt solidification instead of conventional powder sintering. The synthesis process included three steps, namely, combustion reaction, phase separation, and melt solidification. In these steps, phase separation played a key role in producing bulk ceramic materials with high purities and low porosities. It was demonstrated that, in a high-gravity field the phase separation was greatly accelerated, compared with the case under common gravitational condition. In comparison with powder sintering, high-gravity combustion synthesis requires no furnace and can reduce the processing time for the fabrication of bulk ceramic materials.
Phase Transformation Temperature Adjustment of Calcium Chloride Hexahydrate
Authors: Zhu Xiao Qin , Hu Jin , Zhao Hui Yuan , Li Wei Huan
Published: June 2012

Phase change temperature adjustment of calcium chloride hexahydrate added small quantity of barium hydroxide and strontium chloride hexahydrate was researched. The experimental results demonstrated that, its phase change temperature adjustment could be achieved by means of adding excess water, and its suitable adjustment range of phase change temperature was 21.76°C-26.16°C as the proportion of the added excess water was 0-10% by weight. According to the calculation equation gained by the theoretical regression of the experimental results, its phase change temperature with different proportions of excess water may be forecasted during the suitable adjustment range of phase change temperature. This characteristic is of important application value for temperature control in greenhouse or air conditioning etc.
The Influence of Y2O3 Calcined Temperature on the Performance of ZrO2
Authors: Wang Hong Qin , Jiang Dan Yu , Xia Jin Feng , Feng Tao , Yang Xiu Chun
Published: June 2012

Semiconductor gas sensors utilize porous polycrystalline resistors made of semiconducting oxides.The working principle involves the receptor function played by the surface of each oxide grain and the transducer function played by each grain boundary. In addition, the utility factor of the sensing body also takes part in determining the gas response. Therefore, the concepts of sensor design are determined by considering each of these three key factors.ZrO2 is one of the most commonly used sensitive material, The performances of the different components Y2O3-ZrO2 are studied in this paper.The performances of YSZ Prepared with different Y2O3 powder(untreated and 1300°C preburned) and the Mechanism are explored in this paper.
Extraordinary Adsorption Properties of Nano Porous Hydrophobic Silica Aerogels
Authors: Wei Xiao Qing , Ni Xing Yuan , Zhang Zhi Hua , Shen Jun , Du Ai , Zu Guo Qing
Published: June 2012

The adsorption properties of hydrophobic silica aerogels were studied. Polyethoxy- disiloxanes (E-40), ethanol (EtOH), hydrogen fluoride (HF) were used as silican precursor, solvent and catalyst, respectively, followed by solvent substitution and surface modification to prepare silica aerogels. Scanning electronic microscopy, nitrogen adsorption analyzer, contact angle measurement and Fourier transform infrared spectroscopy were used to characterize the structure and properties of silica aerogels. The conclusion is that the silica aerogels are with good hydrophobicity and the gas adsorption capacities is excellent for toxic gases such as benzene and carbon tetrachloride, which is 2~3 times higher than that of activated carbon fiber (ACF) or granule of activated carbon (GAC). Moreover, the adsorption capacity for organic solvent is 20-30 times of its own weight, which is much larger than that of GAC or Poly vinyl alcohol (PVA). In addition, the adsorption capacity of silica aerogels remains almost the same value after two times of adsorption- desorption processes, which means that the process is recyclable, low-cost and environmental friendly.
Mechanical Properties of ZrO2–LaMgAl11O19 Ceramics
Authors: Min Xin , Fang Ming Hao , Liu Yan Gai , Huang Zhao Hui , Liu Feng Jiao , Tang Chao
Published: June 2012

ZrO2 ceramics have been widely used to many fields with its excellent physical and chemical properties, but the mechanical properties of YSZ ceramics, especially the fracture toughness, decline caused by the failure of the phase transformation toughening at high temperature. In this investigation, plate-like LaMgAl11O19 toughened ZrO2 ceramics were prepared by pressureless sintering at 1550 °C for 3h in air . The bulk density of the sintered samples are between 5.5 to 6.0 g/cm3, and the relative density are above 93%. The mechanical properties of the ZrO2-LaMgAl11O19 ceramics were studied systematically at room temperature. The flexure strength and fracture toughness of ZrO2-LaMgAl11O19 ceramic are 811.8 MPa and 13.9 MPa•m½ with the LMA addition of 2wt%.
Anti-Bullet Property of Encapsulated AD95 Al2O3 Ceramic
Authors: Gao Ju Bin , Wang Yang Wei , Wang Fu Chi
Published: June 2012

2024Al and SiC/2024Al were used to encapsulate the AD95 Al2O3 ceramics by Vacuum-high Pressure Infiltration Method. Their anti-bullet properties are not good with Efm of 5.17 and 4.65 respectively, and is far lower than that of the ceramic without encapsulation. The latter one can generate higher hydrostatic pressure between the bullet and ceramic during penetration process. However, in encapsulated targets, the ductile materials in front of the ceramic can decelerate the bullet, so the pressure between bullet and ceramic is not great enough to break the bullet. Propagated microcracks along with the bonding interface were observed in plates consisting of encapsulated Al2O3. These microcraks lead to the interfacial debonding between Al2O3 and encapsulating materials. Consequently, the anti-bullet property of the ceramic encapsulated by metal or composite is depressed. Further more, the different interface bonding conditions and fracture modes cause the discrepancy of anti-bullet property in two kinds of targets with encapsulation structure.
Formation and Evolution of Tribo-Layer on Al2O3 and Al2O3-Based Ceramics in Sliding against Si3N4 under Dry Sliding
Authors: Shang Jian , Lu Jin Jun , Meng Jun Hu , Wang Tao
Published: June 2012

Alumina (Al2O3) and Al2O3-based ceramics are candidate wear-resistant materials for many applications. In the past decades, the friction and wear behaviors of Al2O3 and Al2O3-based ceramics in dry sliding and lubricated conditions have been extensively investigated. In dry sliding, surface modification of Al2O3 and Al2O3-based ceramics at tribo-interface can be observed. In other words, the original surfaces of Al2O3 and Al2O3-based ceramics can be modified by friction and friction-induced material interaction (fracture, mechanical mixing, tribo-sintering) at the tribo-interface, and hence give birth to a tribo-layer. The formation and evolution of the tribo-layer on the worn surfaces of Al2O3 and Al2O3-based ceramics are the keys to understand the friction and wear behaviors of Al2O3 and Al2O3-based ceramics. This is conducted by scanning electron microscopy (SEM) observation and classification of the morphology and composition of the worn surfaces of Al2O3 and Al2O3-based ceramics at different sliding stages. The typical characteristics of the tribo-layers on the worn surfaces of Al2O3 and Al2O3-based ceramics in sliding against Si3N4 in a reciprocating motion are smooth surface with many interlinked cracks in morphology, mechanical mixing in chemical composition. The condition allowing the formation of the tribo-layer is briefly discussed.
Synthesis of Methacryloxypropyltrimethoxysilane Grafting Silica Cryogels Using Xylene as Solvent
Authors: Cheng Hao Liang , Miao Lei , Su Li Fen , Tanemura Sakae , Xu Gang
Published: June 2012

Grafting methacryloxypropyltrimethoxysilane (MPS) onto the surface of silica nanoparticles is the most common approach in surface chemical modification. Traditionally, ethanol or toluene was used as solvent in the grafting process. However, using ethanol as solvent brought about poor grafting result and toluene being regulated was also not an ideal grafting solvent. In order to overcome these disadvantages, we widen the grafting solvents and a novel solvent of xylene was utilized to prepare MPS grafting silica cryogels in this study. The hydrolysis of MPS was in the mixture of methanol and water using diluted hydrochloric acid solution as a catalyst. Both original and MPS-grafted samples were characterized by fourier transform infrared spectrometer (FTIR), thermogravimetric analysis (TG) and other methods. The results showed that xylene is an effective solvent in the process of grafting and the MPS was chemically bonded onto the surfaces of nano-silica particles.
Synthesis of Plugged Mesoporous SBA-15-Type Silicas from Sodium Silicate
Authors: Shan Wei Jun , Wang Wei , Ru Hong Qiang
Published: June 2012

Nonionic triblock copolymers (P123) templated SBA-15 silicas since 1998 have attracted great interests due to their larger pores, thicker pore walls, etc. Following that, extensive works were devoted to tailor the textural and morphological properties of SBA-15s, among which the SBA-15 with plugs formed in mesoschannels, called plugged hexagonal templated silica (PHTS), was one of famous examples. This work presents a simple but effective method to prepare PHTS-type SBA-15s based on the partitioned cooperative self-assembly process using P123 as template and cheap sodium silicate as silica precursor, which is in contrast with most other works using TEOS as silica precursor. Various techniques, including XRD, TEM and N2 sorption, have been employed to characterize the resultant PHTS-type SBA-15s. For this method, synthetic parameters, especially the interval time and aging temperatures, were found to have great influence on the plugged mesostructures.
Thermal Properties of Magnesium Hydroxide Using First-Principles Method
Authors: Ren Qing Li , Luo Qiang
Published: June 2012

The thermal properties of the magnesium hydroxide crystalline powder samples, which were prepared by us, were investigated by first-principles method. The calculated results show that the forbidden band of phonon appears in both 14～19 THz and 33～102 THz. There are 3 acoustic lattice wave branches and 12 optical ones, where two horizontal acoustic branches are degeneracy and two horizontal optical ones are degeneracyhe. Moreover, The constant-volume specific heat quickly increases at low temperature; but it tends to be flat at high temperature. Besides, the Debye temperature quickly increases to 483K from temperature 0K to 10K; but from temperature 100K to 1000K, it is linear with temperature approximately, whose increasing rate is about 1.333; at temperature of 1000K, the Debye temperature is 1930K, reaching its maximum.
Preparation and Properties of MgAl2O4-CaAl12O19 High Temperature Composite
Authors: Wang Yong Hong , Liu Yan Gai , Yang Tao , Huang Zhao Hui , Fang Ming Hao
Published: June 2012

The utilization of lightweight refractories plays an important role in reducing the energy consumption of industrial furnaces. In this paper, MgAl2O4-CaA112O19 high temperature composite was synthesized via solid state reaction using magnesite, dolomite and industrial alumina as raw materials. The influences of raw materials and reaction temperature on phase compositions and microstructure of the composite were investigated by XRD and SEM，respectively. The parameters to prepare MgAl2O4-CaA112O19 high temperature composite were optimized. The results show that the optimum reaction conditions for synthesizing MgAl2O4-CaA112O19 composite is the CA6/MA weight ratio of 2:3, and the reaction temperature of 1500°C for 4h. The CaA112O19 crystals showed laminated or plate-like structure, and the MgAl2O4 showed spherical morphology. The reaction temperature had little effect on the phase compositions of MA-CA6 composite in this experiment. The content of Al2O3 in the raw material affected the phase composition of MA-CA6 composite.With the increase of the CaA112O19 amount, the bending strength of the composite decreased.