Table of Content

15 August 2017, Volume 46 Issue 8

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Study on Six Sapphire Ribbons Crystal Grown by Edge Defined Film Fed Growth

ZHU Yan-feng;WANG Ping;WU An-hua

2017, 46(8):  1425-1429. 

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The six sapphire ribbons single crystal was grown by edge defined film fed growth (EFG) method.Single crystal size is 350 mm×80 mm×2 mm.The appropriate thermal field as the radial temperature 2.9-4.6 K/mm and growth speed control between 5-10 mm/h were determined by CGSim simulation software simulation calculation and experimental verification.The crystallization of the crystal had proved by test crystal rocking curve, the peak intensity is very high and symmetry, and rocking curve of half high FWHM is 16.946″.The crystallization of the crystal is good.Crystal dislocation density was calculated through corrosion in level 103, and the middle crystal dislocation density is less than the crystal on both sides.The bending strength of six sapphire ribbons single crystal was tested, and the highest strength is 1583 MPa, the middle crystal strength is greater than both sides.

Effect of the Heat-shield Spacing on the Crystal Growth of Kyropoulos Sapphire

YANG Yi-han;LI Jin;WANG Chang-chun;GAO Mang-mang;KANG Shao-fu;LI Yan

2017, 46(8):  1430-1435. 

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The continuous development of high technology in the field, such as the deep-space, military and scientific research, has greatly promoted the demand for sapphire crystals.Kyropoulos method is one of the main manufacturing methods of sapphire crystal;the thermal field structure has an important influence on the quality of sapphire crystal.This paper studies the spacing of the new heat-shield structure with 7 internal layers of zirconia and external 8 layers of metallic molybdenum in the process of manufacturing sapphire.The influence of heat-shield spacing on the power consumption, solid-liquid interface shape and crystal thermal stresses of single crystal was investigated by numerical calculations;the reasonable heat-shield structure was determined.The results were compared with the experimental results.It show that the power consumption of growth furnace is obviously improve with the increase of heat-shield spacing, and cause the solid-liquid interface convexity increase, as well the Von-Mises stress decrease.Consideration of the co-exerted effects of heat-shield spacing on the power consumption, solid-liquid interface shape and crystal thermal stress, the optimal heat-shield spacing is determined as 5 mm, which resulted in the lowest energy consumption, and could implement to fabricate high quality sapphire crystal.

Structure and Properties of Novel Mulit-functional Crystal Cd4TbO(BO3)3

JIA Li-sha;ZHAO Ying;TU Heng;HU Zhang-gui

2017, 46(8):  1436-1441. 

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A new cadmium-rare earth (Tb) oxyborate Cd4TbO(BO3)3 was synthesized through high-temperature solid-state reaction in platinum crucibles and its crystal was successfully grown using NaF-B2O3 as flux.Single crystal X-ray diffraction exhibits that Cd4TbO(BO3)3 crystallizes in the monoclinic space group of Cm with unit cell parameters a=7.982(1) (A), b=15.806(3) (A), c=3.487(7) (A), α =90°, β=100.57°, γ=90°.The IR and Raman spectra indicate that (BO3) is the only anion group in the Cd4TbO(BO3)3 crystal.Furthermore, the UV-vis-NIR reflectance spectrum indicates that the transmittance of Cd4TbO(BO3)3 crystal in the range of 500-1500 nm is greater than 70;.The content of Tb is 4.624×1021/cm3 per unit volume of crystal 0.3 times of the content of Tb per unit volume of TGG crystal, suggesting that Cd4TbO(BO3)3 is a fairly promising mulit-functional crystal.

Effect of Blank Particles Forming and Atomized Liquid Content on Dry Granulation Process

LIAO Da-hai;ZHU Zuo-xiang;WU Nan-xing;YU Dong-ling;CHEN Tao

2017, 46(8):  1442-1449. 

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In order to study the relationship between the granule formation and the content of atomized liquid in dry granulation process.Based on Eulerian-Eulerian two-fluid model to simulated the mixing process of blank particles and atomized liquid in dry granulation process.The fluidity index, particle gradation and roughness of the blank particles were analyzed in experiment.Verified the correctness of numerical simulation results.Simulation results express when the atomized liquid content is 100 mL, 200 mL and 300 mL, there is no significant difference in the particles' dispersion in granulation chamber, agglomerate phenomenon is not obvious.When the atomized liquid content is 400 mL, 500 mL, there has significant difference in the particles' dispersion in granulation chamber.Agglomerate phenomenon is obvious.Experimental results show when the atomized liquid content is 100 mL, 200 mL, 300 mL, 400 mL and 500 mL.The fluidity index of the billet particles is 63.5;, 83.0;, 90.0;, 77.0;, 61.0;.Percentage of effective particles is 72;, 83;, 90;, 82;, 65;.Average roughness coefficient is 1.38, 1.43, 1.26, 1.49, 1.57.Comprehensive analysis show the result of numerical simulation is agreement with the experiment, when the atomized liquid content is 300 mL in granulation process, the particles' dispersion in granulation chamber is good and there has no agglomeration.The fluidity of particles is optimal, particle gradation is the most uniform, roughness is the optimal.Which means granulation effect is the best.

Study on the Piezoelectric Properties of Rhombohedral Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 Crystal

WEI Ya-jiao;ZHOU Guo-xiang;ZHANG Xin;BAI Xue

2017, 46(8):  1450-1455. 

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The distribution in 3D space of the piezoelectric coefficient d15, d24, d31, d33, d36 and the electromechanical coupling factor k15, k24, k31, k33, k36 of the rhombohedral PMN-0.33PT crystal were investigated by rotating the coordinate system twice.The functions of the coefficients and the factors stated above about the coordinate rotation angle were obtained.The 3D figures, the maximum values of these coefficients and the rotation angle corresponding to the maximum value are achieved by MATLAB program.It is found that d31, d36, k31 and k36 change dramatically in different direction besides d33 and k33.The maximum value of d31 and k31 of the crystal after rotation expand 15 times and 6 times respectively compared with the measured value of the original coordinates.The maximum value of d36 and k36 which are both zero in the original coordinates can reach 1340 pC/N and 0.73 respectively after rotation.It is instructive for the application of the PMN-0.33 PT crystal in piezoelectric sensors and transducers.

First-principle Calculation of Electronic Structure and Optical Properties of P and Al Doped Cubic Ca2Si

CEN Wei-fu;YANG Yin-ye;FAN Meng-hui

2017, 46(8):  1456-1463. 

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Energy band structure and optical properties of cubic Ca2Si and P(Al)-doped Ca2Si have been calculated by density functional theory of the first-principles pseudo potential wave method.The results show that the energy band of cubic Ca2Si is a direct semiconductor with the band gap of 0.55483 eV.The valance bands are mainly compose of Si 3p and Ca 3d 4s, the conduction bands mainly composed of Ca 3d 4s and Si 3p, the static dielectric function is 11.92474, the refractive index is 3.45322.The P-doped cubic Ca2Si is an n-type direct semiconductor with the band gap of 0.42808 eV.The valance bands are mainly compose of Si 3p, P 3p and Ca 3d 4s, the conduction bands mainly composed of Ca 3d, P 3p 3s and Si 3p, the static dielectric function is 7.92698, the refractive index is 2.81549.The Al-doped cubic Ca2Si is an n-type with the band gap of 0.26317 eV.The valance bands are mainly compose of Si 3p, Al 3p and Ca 3d, the conduction bands mainly compose of Ca 3d 4s, Al 3p 3s and Si 3p, the static dielectric function is 17.02409, the refractive index is 4.12603.The reflectivity are decrease and the absorption are increase by P(Al)-doped.The electronic structure and optical properties of Ca2Si is effectively modulate by doped, the results offer theoretical data for the experimental study of the cubic Ca2Si.

Investigation of YBa2Cu3O7-δ Film Deposited in O2/Ar Mixture Atmosphere by Pulsed Laser Deposition

DAI Xiu-hong;ZHANG Yu-sheng;GE Da-yong;LOU Jian-zhong;ZHAO Hong-dong;LIU Bao-ting

2017, 46(8):  1464-1469. 

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The YBa2Cu3O7-δ(YBCO)superconducting film was fabricated epitaxially on STO(001) substrate by pulsed laser deposition method (PLD) in O2/Ar mixture atmosphere with the mass flow rate ratio of 1∶3.The density of the particles with submicron to micron-sized distributed on the film surface is lower compared with the YBCO film deposited by traditional PLD method.The supconducting transition temperature (Tc) is above 90 K measured by DC resistance as well as the magnectic susceptibility.The zero field critical current density (Jc) is 63.8 MA/cm2, 28.3 MA/cm2 and 8.7 MA/cm2 at 40 K, 65 K and 77 K, respectively.The flux pinning force density reaches the maximum of 387.9 GN/m3 at 5.2 T, 71.3 GN/m3 at 2.6 T, and 12.1 GN/m3 at 0.91 T at 40 K, 65 K and 77 K, respectively.The experimental results provide valuable reference for further study of superconducting films deposited in Ar/O2 mixture atmosphere by PLD method.

Effect of Sputtering Pressure on Transmittance and Optical Band Gap of Silicon Oxycarbide Thin Films

FENG Jian;JIANG Hong;MA Yan-ping;NA Cong;WANG Qi

2017, 46(8):  1470-1475. 

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Silicon oxycarbide (SiOC) thin films were fabricated on Si (100) and glass substrates by radio frequency (RF) magnetron sputtering technique.They were also characterized by scanning electron microscope (SEM), X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy as well as UV-Vis spectroscopy.The component, transmittance and optical band gap of the films deposited under different sputtering pressures were also studied.The results show inside of thin films, the component of sp3 band, transmittance and optical band gap both increase follow the sputtering pressure's increase.The sp3 band and its wide gap σ band have a great influence on the optical band gap of films which is 2.67 eV when the sputtering pressure equal 3.0 Pa.

Effect of ZrO2 on Microstructure and Mechanical Properties of AlN Ceramics Prepared by Hot-Pressing Sintering

LIU Cong;GUO Wei-ming;FU Jun-yu;TONG Wen-xin;WU Shang-hua

2017, 46(8):  1476-1479. 

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The AlN ceramics were hot pressed by the addition of nanoscale ZrO2 power as second phase and Y2O3.The results show that AlN ceramics mainly comprise main phase AlN phase, grain boundary phase Al5Y3O12 and new phase ZrN.With the addition of ZrO2, the Vickers hardness of AlN ceramics has no significant change, while fracture toughness gradually increase.This is because the transformation of fracture mode from intergranular fracture to mixed fracture including intergranular fracture and transgranular fracture which is induced by the formation of ZrN due to the reaction between ZrO2 and AlN, strengthened the grain boundary and then improved fracture toughness.

Study on the Gas Sensing Properties of PbS Quantum Dots/MoO3 Nanobelts at Low Temperature

CAO Min-chi;LIU Yang;HOU Shu-xin;CHEN Chun-run;XU Teng;HE Jing;YANG Shuang;WANG Hao-ran;LI Xin-hong;LIU Yue-li

2017, 46(8):  1480-1486. 

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PbS quantum dots (QDs) decorated MoO3 nanobelts were prepared by liquid phase method.The composition, structure and morphology of PbS QDs/MoO3 nanobelts were charactered by XRD, FESEM, TEM and EDS measurements.Gas sensors based on MoO3, PbS QDs and PbS QDs/MoO3 nanobelts were assembled using commercial ceramic tubes and their gas sensing properties towards NH3 were tested.The results show that gas sensors based on PbS QDs/MoO3 nanobelts have a good gas sensing response to NH3 at a relative low temperature range (20-100 ℃), and the lowest detect limit is 10 ppm.PbS QDs are uniformly dispersed on the surface of the MoO3 nanobelts, and then the formed heterojunction interface may favor for the separation of electrons and holes, which will greatly improve their electron transfer ability and gas sensing performance.

Molecular Dynamics Simulation Study on Proton Diffusion in SPEEK/PVDF-g-PSSA Blending Membrane

SUN Wei;WANG Yu-xiang;MA Yue;QIU Bei-bei;XU Zhi-yan;ZHOU Qiong;LU Gui-wu

2017, 46(8):  1487-1492. 

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To explore the performance of based modified sulfonated poly(ether ether ketone) (SPEEK) membrane for proton exchange membrane fuel cells(PEMFC), the microstructure and proton transfer performance of SPEEK/PVDF-g-PSSA blending membrane were studied.The effect of water content on structural and dynamical characteristics of blending membrane was investigated by molecular dynamics(MD) simulation technique.It was observed that as the water content increase, the number of water clusters and proton conductivities first increase rapidly.When the water content reaches saturation (λm=20), the calculated proton conductivity is 105 mS/cm, which was coincident with the results of experiment (96 mS/cm).When the water contentin creases to greater than the saturation value, the distance between sulfur atoms increases, and proton conductivity tends to be stable.

Synthesis and Luminescence Properties of Bi4Si3O12∶Sm3+ Phosphor

ZHANG Fang-yuan;XIE Jian-jun;WANG Tun;LIN De-bao;XIAO Wei-qin;SHI Ying;LEI Fang;ZHANG Lei

2017, 46(8):  1493-1497. 

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Bi4Si3O12∶Sm3+ phosphors were prepared by a sol-gel technique.The crystal structure and its luminescence properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectra (PL).The phase of the synthesized samples calcinated at 850 ℃ is pure Bi4Si3O12 according to X-ray diffraction results.The luminescence spectra shows that Bi4Si3O12∶Sm3+phosphors could be excited effectively by the light from ultraviolet ray to blue light.The energy transfer process from Bi3+ to Sm3+ under 260 nm excitation was discussed.The obtained phosphors exhibites a strong band at 468 nm belonging to the 3P1→1S0 transition of Bi3+, and another three emissions peaks at 563 nm, 600 nm, and 649 nm, which comes from4G5/2 → 6HJ(J=5/2,7/2,9/2) transition of Sm3+.While under excitation with 467 nm, only characteristic emission of Sm3+ corresponding to the4G5/2 → 6HJ(J=5/2,7/2,9/2) transition are found.The optimum dopant concentration of Sm3+ in(Bi1-xSmx)4Si3O12 is 3mol;.

Effect of In-situ Synthesis of TiB2 Particles on Microstructure and Mechanical Properties of B4C Ceramics

HAN Wei-yue;LIN Wen-song;WU Xiao;WU Fen;XU Bin-huan

2017, 46(8):  1498-1502. 

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Boron carbide is a kind of potential structural ceramic with wide application.Boron carbide has excellent properties such as low density, high strength, high hardness, abrasion resistance and corrosion resistance, but it has the characteristics in poor toughness and high sintering temperature that limit its broader application.TiB2-reinforced B4C ceramics were prepared by in-situ synthesis and Si-infiltration reaction sintering.The mechanical properties and microstructures of composite ceramics with TiO2 particles were investigated.The results show that the distribution of in-situ particles is more uniform and the grain size is more fine;and the distribution of TiB2 is on the boundary of B4C.It plays a positive role in the toughening and strengthening of B4C ceramic materials.When the amount of TiO2 addition reaches 8wt;, the maximum flexural strength is 269 MPa and the maximum fracture toughness is 7.73 MPa·m1/2, which is 2.46 times of B4C ceramic material with TiO2 content of 0wt;.

Insights on Catalytic Activities of Transition Metal Selenides as Efficient Counter Electrode Materials for Dye-sensitized Solar Cells

GUO Jia-hao;SHI Yan-tao;MA Ting-li

2017, 46(8):  1503-1510. 

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Exploiting an alternative of the Pt-based counter electrode (CE) materials for triiodide reduction reaction has become a major interest in the fundamental research of dye-sensitized solar cells (DSCs).Transition-metal selenides (TMSes) was proved a promising non-precious metal electrocatalysts and be used as counter electrode in DSCs.However, the research on TMSes as counter electrode material in DSCs is not enough in-depth and lack systematic research.Two TMSes, Cr5.6Se8 and HfSe3 were prepared by a free-reductant solvothermal method and used them as counter electrodes in high efficiency DSCs.The electrochemical results show that these selenides have excellent catalytic activity for the reduction of triiodine/iodine couple, the conversion efficiencies of corresponding DSCs are 7.27; for Cr5.6Se8 and 7.52; for HfSe3, respectively, comparable to DSCs based on sputtered Pt CE.These results further prove the possibility of selenides as a potential CE materials, and provided a basic research for new selenides.

Effect of Sintering Temperature on Properties and Microstructure of Ceramic/Bronze Composite Bond

XIE Yu-bo;HOU Yong-gai;LI Wen-feng;HUANG Qing-fei;DING Zhi-jing

2017, 46(8):  1511-1516. 

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Ceramic/bronze composite bond was prepared by the method of powder metallurgy, and mass ratio of bronze bond (mCu∶mSn=85∶15) to ceramic bond of 3∶1.The influence of sintering temperature on the mechanical properties and structure of ceramic/bronze composite bond were studied though electro-mechanical universal testing machines, rockwell hardness tester, scanning electron microscope (SEM) and X-ray diffraction.The results show that: when sintering temperature arises, the density, bending strength and impact strength of ceramic/bronze composite bond arises first and decreases later.when sintering temperature is 620 ℃, the mechanical properties of ceramic/bronze composite bond reach its maximum, the density is 5.43 g/cm3, the bending strength is 170 MPa, the impact strength is 9.76 kJ/m2 and the hardness (HRB) is 126.The temperature rise promotes Cu and Sn to realize alloyed and also promotes the interaction of the elements of the interface between the bronze and the ceramic.When sintering temperature is 620 ℃, between the copper and tin are all α+δ eutectoid, the interface of metal and ceramic bonded well, which improve the properties of ceramic/bronze composite bond.

Preparation and Performances of Building Ceramic by Molybdenum Tailings

WANG Xiu-lan;TIAN Da-wei;SHI Qing-hui;WANG Guo-liang

2017, 46(8):  1517-1520. 

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Building ceramic was prepared by molybdenum tailings as the main material, clay and quartz as accessories.The effect of sintering system such as sintering temperature and holding time on the performances of building ceramic was studied.The results show that good performance building ceramics can be made with molybdenum tailings as the main raw material by pressing methods.Under the condition of sintered temperature 1165 ℃, holding time 120 min, the prepared sample exhibited the following properties of bending strength 46.85 MPa, water absorption 0.43;, bulk density 2.23 g/cm3.Building ceramic made by molybdenum tailings can convert solid waste into a production, and form a closed production chain.It not only consumes a large number of industrial solid waste, but also reduces the pollution to the environment, which has good environmental benefits.

Study on Composition and Structure of Carbon Doped Ti-O Thin Films Prepared by PEM Control

XUE Jian-lu;WEN Feng

2017, 46(8):  1521-1526. 

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Carbon doped Ti-O (C∶Ti-O) films were prepared using CO2 and O2 as carbon and oxygen source, and during the deposition Plasma Emission Monitoring (PEM) system was used to realize the closed-loop control of reaction gas and stabilize the reactive sputtering in the hysteresis transition region.The surface morphology, structure and composition of the films were characterized by AFM, Grazing Incidence X-ray Diffraction and XPS.The transmittance of the films was measured by UV-Vis spectrophotometer and the bandgap of the thin films was also calculated by Tauc mapping method.The results show that with the increase of the glow intensity set point (SP), the deposition rate and Ti-C bond content in the C∶Ti-O thin film increase, the bandgap decrease.Increasing SP can enchance the crystallinity of the film and is favorable to the formation of the rutile phase.

Preparation, Microstructure and Adsorption Properties of Co-MgAl Ternary Hydrotalcite-like Compounds

QIU Man-de;HAN Qing-jiao;CUI Yan-long;LI Xu

2017, 46(8):  1527-1533. 

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Co-MgAl ternary hydrotalcite-like compounds (HTLcs) were prepared by hydrothermal method.The different Co2+ ratios on the phase composition, crystal structure and crystal growth of HTLcs were investigated by the X-ray diffraction (XRD) and scanning election microscopy (SEM).Simultaneously, the growth mechanism was discussed by the ligand field theory.The adsorption performance and mechanism of calcined Co-MgAl-HTLcs and MgAl-LDHs were comparative investigated with methyl orange (MO) as the adsorption object.The results show that there is exchange exists in Mg2+ and Co2+ at layer board.The lamellar structure of hydrotalcites are not affected at different Co2+ ratios, but the each crystal planes growth of Co-MgAl-HTLcs are affected during the crystal formation process.The calcined Co-MgAl-HTLcs of Co∶Mg∶Al=1∶2∶1 can maintain sheet structure after 500 ℃ calcining.But the crystal size and thickness slightly are decrease compared with that before calcined, the homogeneity and regularity of the product became relative poorer than before calcined.The adsorption decolorization performance of Co-MgAl-LDO is slowly increasing with the time increase on MO simulated dye wastewater.It took the longer to reach adsorption equilibrium for 70 min.The decolorization rate is only to 60;, which is the lower than the MgAl-LDO (90;).The adsorption kinetic study shows that the adsorption process of Co-MgAl-LDO on the MO is more consistent with the quasi-second-order kinetics equation, and the adsorption isotherm is in accordance with the Freundlich model.The adsorption process of MgAl-LDO is more consistent with the quasi-first order kinetic equation, its adsorption isotherm conforms to the Langmuir model.

Study on Preparation and Growth Mechanism of Potassium Titanate Whisker

FAN Jing;ZHOU Xue-song;CAI Yong-feng;CHANG Shi-yan;SHEN Yi;MENG Yan-zhi

2017, 46(8):  1534-1539. 

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Potassium hexatitanate (K2Ti6O13) whiskers were successfully prepared by the kneading-drying-calcination(KDC) method.The influence of the sintering time and sintering temperature on the crystallization process of the K2Ti6O13 whiskers were investigated by a thermogravimetric and differential thermal analysis.The phase composition and crystal indices of the K2Ti6O13 whiskers were analyzed by X-ray diffraction.Furthermore, the microstructure of the whiskers was investigated by scanning electron microscopy and transmission electron microscopy, which revealed that the growth mechanism of the K2Ti6O13 whiskers.

Effect of Al Pre-treatment to Substrate on the Properties of AlN

JIA Hui;SHI Lu-shan;HUANG Xin;YE Tai-bing

2017, 46(8):  1540-1544. 

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The aim of this paper is to examine the effects of TMAl preflow on the properties of AlN epitaxial layer grown on c-plane sapphire substrates by metalorganic chemical vapor deposition (MOCVD) using high-temperature treatments.The entire epitaxial growth process was monitored by in situ Epitt.At the same time, the surface morphology and crystal quality of AlN epitaxial layer were studied.The results show that TMAl preflow leads to the decrease of the crystal quality of the AlN epitaxial layer, and it also has a significant effect on the strain.

Preparation of Tetragonal Barium Titanate Nanopowders by Oxalate Co-precipitation Assisted with Microwave Method

CHEN Jie;ZHANG Qing;CHE Ming-chao

2017, 46(8):  1545-1551. 

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The high purity and good crystallinity tetragonal barium titanate (BT) nanopowders were prepared by oxalate co-precipitation assisted by microwave method using tetrabutyl titanate and barium nitrate as the main raw materials.The structure, diameter and profile of the nanopowders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The results show that under the condition that the mole ratio of barium and titanium is 1, the microwave reaction is at 80 ℃ for 30 min, the calcination reaction is at 700 ℃ for 1 h and with the addition of surface active agent (OP-10), barium titanate (BT) nanopowders with a diameter of about 50 nm and c/a ratio of 1.0069 can be prepared.The microwave temperature and microwave time can affect the tetragonality of barium titanate nanopowders significantly.

Band-gap Control and Photocatalytic Properties of Fe Doped TiO2 Ultrafine Powders

LIU Shao-you;ZUO Cheng-gang;CHEN Yuan-dao;ZHOU Shi-biao

2017, 46(8):  1552-1558. 

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Fe doped TiO2 ultrafine powder materials (Fe-TiO2) were synthesized though a simple solid-state reaction method at a low-temperature.The textural properties of these materials were characterized by XRD, UV-Vis, SEM/EDS, N2 adsorption-desorption.And the influence of material for engery band-gap from various feed ratios and templates, the intrinsic relations between the microstructural parameters and photocatalytic degradation of pyridine were investigated.The results show that Fe3+ entering into the lattice of anatase TiO2 is mainly from the c-axis by isomorphous replacement and thus the charge density of c-axis projection direction increases.Moreover, the effective regulation of energy band-gap for the Fe-TiO2 powders is determined by the different templates and various feed molar ratios of nFe∶nTi, but the regulation function of the template is relatively obvious.And it is a positive correlation between the lattice mismatch rate and photocatalytic performance.Under the CTAB as template and the various feed molar ratios of nFe∶nTi, the visible light degradation rate (k) of the pyridine solution on Fe-TiO2 powders follows as kFe-TiO2(nFe/nTi=5∶10) (98.27;)>kFe-TiO2(nFe/nTi=3∶10) (89.63;)>kFe-TiO2 (nFe/nTi=2∶10) (83.68;)>kFe-TiO2 (nFe/nTi=1∶10) (78.08;)>kTiO2(10.13;), and on the condition of the ratio of nFe/nTi=1∶10 with different templates, the k value is kSDS(94.24;)>kCTAB(78.08;)>kSDBS(70.15;)>kDHSB(64.58;).However, the photocatalytic degradation efficiency of pyridine mainly depend on the energy of photogenerated carriers rather than the specific surface area and the width of energy gap.

Controllable Preparation and Photocatalytic Properties of Nano-CeO2 Sphere and Sheet

WANG Zhu-mei;ZHU Xiao-ling;LI Yue-ming;SHEN Zong-yang;ZUO Jian-lin

2017, 46(8):  1559-1563. 

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Using ethylene glycol, water and propanoic acid as solvent, precursor with sheet and sphere shape was first synthesized by template-free solvothermal method through varying the volume ratio of ethylene glycol under 180 ℃.Then CeO2 nano-sphere and nano-sheet was prepared by calcinating the precursor at 500 ℃ for 2 h in the air.The properties of the samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Ultraviolet-visible spectroscopy (UV-Vis DRS).The photocatalytic properties to methylene blue solution were investigated under visible light irradiation.The results show that the CeO2 still kept the shape of the precursor with sheet and spherical morphology after calcination, which was assembled by nanoparticles.The diameter of CeO2 nano-sheet is 0.3-1 μm and the thickness is 20-60 nm.The diameter of CeO2 nano-sphere is about 120-200 nm.CeO2 nanostructures could decrease the band gap energy, increase the specific surface and make the absorption edges red shifting, which significantly increase the photocatalytic activity.The photocatalytic degradation rate of MB in 3 h increased from 12.3; for rod-like CeO2 to 80.1; for CeO2 nano-sphere and 91.2; for CeO2 nano-sphere, respectively.

Preparation and Luminescence Properties of Ca-α-SiAlON∶Eu Phosphors from Ca-Si-Al-O Glass

TANG Yun;HE Jie;ZHANG Xue-ping;TIAN Peng-fang;ZHANG Si-si;XUE Pei

2017, 46(8):  1564-1568. 

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Ca-α-SiAlON∶Eu phosphors were synthesized from Ca-Si-Al-O glass with the addition of Eu2O3 by carbothermal reduction nitridation (CRN) method.The phase composition, microstructure and luminescence properties of the obtained Ca-α-SiAlON∶Eu were investigated by X-ray Diffractometer (XRD), Scanning Electron Microscope (SEM), UV-Vis spectrophotometer and fluorescent spectrophotometer.The results show that: (1)The chemical structure of Ca-Si-Al-O glass prepared from CaO, Al2O3 and SiO2 can be generally described as frame structure of SiO4 tetrahedra branched with AlO4 tetrahedra;(2) Ca-α-SiAlON doping with Eu ion with prismatic morphology are prepared at 1450 ℃ from Ca-Si-Al-O glass with the addition of Eu2O3 by CRN;(3) The obtained Ca-α-SiAlON∶Eu has high adsorption in the UV-visible spectral region.Under the excitation of 420 nm, the Ca-α-SiAlON∶Eu exhibited an intense greenish yellow emission centered at 570 nm, which is attributable to the allowed 4f65d-4f7 transition of Eu2+.

Influence of Microwave on the Structure and NH3-SCR Denitration Activity of Cu-ZSM-5 Catalysts

TANG Jian-xiao;MA Li-ping;WANG Dong-dong;WANG Qian-qian

2017, 46(8):  1569-1574. 

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Copper-based ZSM-5 zeolite catalysts were prepared using different ways of drying, the microwave drying and the conventional way, that is, electric blasting drying, based on incipient wetness impregnation method.XRD and N2 physisorption techniques were employed to investigate the effect of drying method on porous structure, phase structure as well as catalytic activity.The results show that copper introduction significantly promotes the catalytic activity;below 200 ℃ the catalytic activity of the microwave-dried M-4Cu-ZSM-5 is slightly higher than the conventionally-dried 4Cu-ZSM-5, while between 200-300 ℃ the latter exhibites superior catalytic performance;porous structure, crystal size and distribution of the active species of the catalyst were directly affected by the microwave treatment, causing the differences in catalytic activity.

Synthesis of Three-dimensional Ag2O/WO3 and Investigation of Its Photocatalytic Activity

HE Xiao-yu;LI Chun-xia

2017, 46(8):  1575-1579. 

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Due to WO3 with the band bap of about 2.7 eV, visible light can be used to stimulate the photocatalytic activity, which greatly improve the utilization rate of sunlight.However, the photocatalytic activity of pure WO3 nanopowder is relatively low.In order to solve this problem, WO3 nanonetworks were used as the 3D frame for loading Ag2O nanoparticles.Ag2O/WO3 heterostructures composite were prepared with different molar ratio of WO3 to Ag2O via a simple chemical precipitatation method.To explore the photocatalysis of the heterostructures, the photodegradation of methylene blue was carried out under simulated sunlight irradiation.Photocatalytic activity was enhanced by loading Ag2O nanoparticles on the WO3 networks and the optimum molar ratio of WO3 to Ag2O is 1∶2.Then the photocatalysis decreased with the excessive amount of Ag2O, which may be attributed to the recombination of electrons form WO3 and holes from Ag2O.

Preparation of Mesoporous Carbon-loaded Ce-TiO2 and Its Photocatalytic Degradation of Methylene Blue

SU Shuai;XU Qing;FAN Dong-mei;ZHAI Chun-yang

2017, 46(8):  1580-1586. 

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The precursor of Ce-Ti metal organic material was synthesised by the hydrothermal method using Ce(NO3)3·6H2O, Citric acid, tetrabutyl titanate (IV) and 2-hydroxy terephthalic acid and N, N-dimethylformamide as raw materials.A series of mesoporous nanocomposites Ce-TiO2 with high specific surface area were obtained by different sintering temperatures.The structures and properties of the composites were characterized by XRD, SEM, BET, TG, UV-vis DRS and UV absorption spectroscopy.The results show that the photocatalyst calcinated at 1000 ℃ (CTOF-P10) exhibits excellent photocatalytic properties.The first-order kinetic constant of the degradation of methylene blue (MB) is 2.15 times higher than that of commercial TiO2 (P25).The introduction of Ce ions plays the role of doping, it's preventing the growth of TiO2 grains, and also inhibits the recombination of photogenerated electrons and holes.Consequently, the photocatalytic activity of the synthetic catalyst is dramatically enhanced.

Theoretical Study on Electronic Structure and Li-ion Diffusion Property for LiVPO4F

ZHOU Chuan-cang;ZHANG Fei-peng;WU Hong-yu;ZHANG Jiu-xing

2017, 46(8):  1587-1592. 

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The lattice structure, electronic structure, magnetic property, insert voltage and the Li-ion diffusion properties of LiVPO4F cathode material have been investigated by first-principle calculation method based on the density-functional theory.The calculational results show that the lattice structure of LiVPO4F remains stable during the process of desorption of the Lithium.The percentage of volume change is only 3;;this can be attributed to the stability of P-O covalent bond.The bands near Fermi energy level are mostly formed by V-3d orbital electrons and the band gap energy of LiVPO4F is decreased.The spin polarization phenomenon is found for both systems and the magnetic moment decreases after desorption of Lithium.The averaged insert voltage of LiVPO4F is 4.53 V, which is in agreement with the experimental value of 4.30 V.The Li has obviously stronger diffusion capability comparing with others atoms.

Preparation of Pressure Transmitting Medium Composed of Clay Minerals Produced in Henan Province and Enlarged Scale Tests on Diamond Synthesis

YANG Bing-fei;LIU Jie

2017, 46(8):  1593-1597. 

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Clay minerals produced in Henan procince, which have good sealing performance and pressure transmitting property, can take place of pyrophyllite in the use of pressure transmitting medium.The new pressure transmitting medium introduced in the paper was made by sealing layer and pressure transmitting layer together.The sealing layer was made by the clay minerals, which were divided into three size range(-1.4 mm+0.5 mm,-0.5 mm+0.25 mm and-0.25 mm) and the weight proportion was 4∶4∶2.whereas the pressure transmitting layer was made by dolomite, which was divided into two size range(-0.18 mm+0.15 mm and-0.15 mm) and the weight proportion was 8∶2.In addition, adding 5; and 8; binder(sodium silicate) to the sealing material and pressure transmitting material respectively.The two kinds of materials were molded by pressure, in which the sealing material was in the outside and pressure transmitting material was in the inside, and roasted at a certion temperature.The external sizes of the new medium were 65 mm×65 mm×32.5 mm, and the size of internal cavity was 38.5 mm.With the pressure transmitting medium, a large number of diamond synthesis tests were conducted.The tests results showed that the per unit yield of diamond was 116.0 ct, the proportion of crystals whose compression strength and grain size were more than 130 N and 40/60 mesh were 28.0; and 77.5; respectively, as well as the cemented carbide anvil consumption was less than 0.28 g per 1 g of the produced diamond.The new medium made by clay minerals has the same effect as that made by pyrophyllite material on diamond synthesis.

Effect of Spinning Aid on the Preparation of Aluminum Titanate Fiber by Non-hydrolytic Sol-gel Method

HU Hai-long;JIANG Wei-hui;FENG Guo;LIU Jian-min;ZHANG Quan;MIAO Li-feng;WU Qian

2017, 46(8):  1598-1603. 

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Aluminum titanate fiber was prepared by non-hydrolytic sol-gel (NHSG) method.The phase transformation process of aluminum titanate were studied by DTA-TG, XRD, TEM, SEM, FE-SEM, and the effects of the type and amount of the spinning aid on the phase and morphology of aluminum titanate fiber were discussed.The results show that aluminum titanate crystal phase can form by NHSG method at 750 ℃, and the introduction of solvent DBE and spinning aid epoxy resin does not affect the low temperature synthesis of aluminum titanate.As a spinning aid, epoxy resin is conducive to form the linear colloidal particles in the sol, resulting in the improvement of the sol.Spinning aid amount is critical to the preparation of aluminum titanate fiber.High quality aluminum titanate fiber, which has smooth surface and compact structure, can be achieved when the mass ratio of aluminum titanate to epoxy resin is 1∶1.

Research and Application on Montmorillonite-based Biofunctional Nanocomposite

SHEN Ke-xuan;LIN Sen;SUN Shi-yong

2017, 46(8):  1604-1607. 

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Research on theory and application of biofunctional nanocompsite has become a focus attention.It is a new interdisciplinary frontier in life science and material science.Clay mineral is a kind of natural silicate minerals with nano structure and it has been widely used due to specific characteristics of layered structure.Its particular structure leds to it has the characteristics of strong adsorption capacity, excellent stability and wide application.The present paper mainly focuses on summarizing montmorillonite-based biofunctional nanocomposite and their applications in the fields of enzymatic catalysis, antibacterial, medicine and environmental protection.The prospects of development of clay mineral-based functional nanocomposites were discussed.

Molecular Dynamics Simulation of Temperature Effect on Methane Hydrate Decomposition

ZHOU Guang-gang;SUN Xiao-liang;LU Gui-wu

2017, 46(8):  1608-1613. 

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Methane hydrate contains high purity methane and water, which is an important strategic resources that can effectively relieve the energy crisis.Methane hydrate decomposition dynamics research involving the hydrate exploitation and application of hydrate technology is the focus of scholars around the world.This article adopts the method of molecular dynamics simulation, style I methane hydrate decomposition kinetics was studied, and the effect of temperature on the microstructure and decomposition rate was discussed.Style I methane hydrate is the object of research, and the influence of temperature on water molecule sequence parameters and radial distribution function was studied.The result shows that in the process of hydrate decomposition, water molecules structure is evolved from the original long range order to long-range disorder and short-range ordered, and is converted from crystal structure of low density to liquid water of higher density.As the temperature of system increases from 270 K to 295 K, the first peak of radial distribution function of carbon-carbon atoms of methane molecules shows a trend of increase, shows that the higher the temperature, the faster the rate of methane escape out of the cage.The study found that in the process of decomposition dynamics of evolution, the AOP sequence parameters of water molecules begin to rise from 0, eventually to stabilize near 0.8.The higher the temperature, the steeper the curve in decomposition of AOP, the faster decomposition of methane hydrate.

Synthesis of Ti Ion Doped LiFePO4/C Composite Material Based on Polymerization Reaction

LI Ling-fang;ZENG Wu-jun;LIU Wan-feng

2017, 46(8):  1614-1618. 

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Firstly, the precursor powder FePO4/PANI was synthesized by polymerization reaction.Then, the cathode material LiFePO4 was synthesized by using LiOH·H2O, FePO4/PANI and PVA as the raw materials.In addition the carbon-coated and Ti4+-doped material were synthesized simultaneously.These three samples were marked as LiFePO4, LiFePO4/C and LiFe0.96Ti0.02PO4/C.Their respective microstructure and characteristics were investigated via XRD, EDS and charge-discharge tests.The XRD patterns agree well with the standard LiFePO4 pattern and without amorphous carbon.Comparing with sample LiFePO4/C, LiFe0.96Ti0.02PO4/C has approximate electronic conductivity and higher Li+ diffusion coefficient.Ti4+ distributes in the lattice evenly.Thus, LiFe0.96Ti0.02PO4/C has better electrochemical performances than the other samples.It's initial discharge capacities are 158.7 mAh·g-1,153.3 mAh·g-1,147.6 mAh·g-1,136.4 mAh·g-1 and 123.5 mAh·g-1 at C/10、C/2、1C、3C and 5C rate respectively.The rate performance and potential stability of LiFe0.96Ti0.02PO4/C are favorable.

Hydrothermal Preparation, Characterization and Its Lithium Storage Performance of MoO3

LI Ye-hua;WU Xian-wen;CHEN Shang;DAI Chun-hui;YU Xiao-lin;WANG Su-liang;LIANG Qi-ying;ZHAO Shen-yong

2017, 46(8):  1619-1624. 

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MoO3 was synthesized by hydrothermal method using sodium molybdate and sodium salicylate as raw material.The structure and morphology of the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and the electrochemical performances of MoO3 were conducted on an electrochemical workstation and a battery tester.The results show that the electrochemical properties of hexagonal MoO3 (h-MoO3) nanobocks prepared by hydrothermal treatment at 180 ℃ for 12 h are much better than the crossed MoO3 (α-MoO3) nanosheets synthesized by hydrothermal treatment at 180 ℃ for 24 h.When it is applied as anodes for lithium ion battery, the initial discharge capacity of h-MoO3 is 2068.1 mAh/g.After 50 cycles, its discharge capacity is 946.4 mAh/g at a current density of 50 mA/g.The outsanding electrochemical performance is attributed to the smaller electrochemical transfer impedance.

Controllable Synthesis and Characterization of Spindle-Like CuO Micro-structure

ZHOU Hai;KANG Min;WU Dong;LYU Bao-liang

2017, 46(8):  1625-1630. 

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Spindle-like CuO micro-sized structures were hydrothermally synthesized using NaOH, urea as precipitant and Cu(NO3)2·3H2O as copper source.The prepared samples were characterized and analyzed by means of XRD, SEM, TEM and HRTEM.The results indicate that the spindle-like CuO exhibited monoclinic phase with high crystallinity.The influence of pH, urea concentration, reaction temperature and reaction time on the growth behavior of CuO was investigated in detail, the results show that the morphology of CuO could be altered by adjusting the relative concentration of NaOH and urea, and thus micro-sized hollow spheres, flower-like structures and spindle-like CuO structures could be obtained.Possible growth mechanism of the spindle-like CuO micro-sized structures was proposed.

Effect of Different Solvents on the Crystallization Properties of Cordierite Powders

LIU Zhen-ying;MA Xiao-li;GUO Zheng-han;LI Jie;XIE Li-na;LIU Yin

2017, 46(8):  1631-1634. 

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Cordierite powders was synthesized by liquid-phase method using TEOS, magnesium and aluminum salts as raw materials.The effects of different solvents and pH value on the crystallization properties of the cordierite powders were characterized by means of DTA-TGA and XRD measurements.The results show that using water as solvent, solution pH value is 4, the cordierite powders sintered at about 1000 ℃ of diffraction pattern is relatively smooth, that phase of μ-cordierite and magnesia alumina spinel occured at 1000 ℃, μ-cordierite and magnesia alumina spinel of diffraction peak intensity begin to decrease at 1200 ℃.The formation of α-cordierite start at 1200 ℃, μ-cordierite phase disappeare, while α-cordierite of peak intensity increase at 1250 ℃, μ-cordierite to α-cordierite transformation is fully completed at 1350 ℃.

Preparation of Graphene Oxide/Polyaniline/Titania for Marine Anti-Corrosion

LIU Xun;GUO Fang;ZHONG Ying-ying

2017, 46(8):  1635-1642. 

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Preparation of aqueous graphene oxide (G) /polyaniline (P) /titanium dioxide (T) composite material in the tartaric solution using graphene oxide as template was presented.Morphologies and crystallizations of as-prepared material were invistigated by TEM, SEM, XRD and IR.Photocatalysis performance and anti-corrosion property of G/P/T material were also investigated by photo-degradation and electrochemical measurements.The results indicate that aniline doped with tartaric acid is dispersed well in solution, and then polymerize into layered graphene oxide (G)/polyaniline (P) with graphene oxide as template, on which nano-TiO2 particles are decorated homogeneously, therefore forming aqueous G/P/T.It is confirmed by the photo-degradation of rhodamine B that G/P/T powder has a good photo-degradation effect, protecting metal material from bio-corrosion.Also, the result shows that G/P/T modified epoxy resin coating could alleviate the corrosion of aluminum alloy, of which self-corrosive current reduces from 10-5 A/cm2 to 10-11 A/cm2.

Effect of Composite Nucleation Agents on Crystallization of Glass-Ceramics Produced by Yellow Phosphorus Furnace Slag

SHANG Zhi-biao;HUANG Xiao-feng;MA Li-ping;LIU Hong-pan;CHEN Dan-li;LIU Xiu-zhuang;ZHAO Dan;FAN Ying-ying

2017, 46(8):  1643-1648. 

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A series of glass-ceramics were prepared by melting method using yellow phosphorus furnace slag as the main raw material and adding different kinds of composite nucleation agents. The crystal phase composition was calculated by FactSage 6.4;the crystallization ability was analyzed by Kissinger equation;the results of simulation and calculation were proved by means of X-ray diffraction and scanning electron microscopy.The results show that compared with adding TiO2, the adding of composite nucleation agents TiO2+CaF2 or TiO2+P2O5 can reduce the crystallization activation energy and promote the crystallization behavior.In the case of adding TiO2+Cr2O3, the effect is opposite.The major crystal phase is wollastonite and the minor crystal phases are aluminian diopside and fluorapatite when any one of TiO2, TiO2+CaF2, TiO2+P2O5 and TiO2+Cr2O3 are added as nucleating agent, which are consistent with the FactSage 6.4 calculation results.

Study on the Al2O3 Contents in Ni-Al2O3 Composite Coatings Predicted by Using BP Neural Network Model

LI Yuan-bin;YUE Wen-xi

2017, 46(8):  1649-1652. 

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A 4×9×1 type of BP neural network model was set up to predict the Al2O3 contents in Ni-Al2O3 composite coatings by using the artificial neural network technology.The content and 3D surface pattern were analyzed by using XRD diffraction and atomic force microscopy (AFM).The results show that when the number of hidden layers is 9, the minimum root mean square error is 1.13;, the fitting similarity R is about 0.99937, which indicates that the BP neural network model can accurately predict the Al2O3 contents.When the duty ratio is 60;, the cathode current density of 4 A/dm2, pH=4, the bath temperature of 55 ℃, Ni-Al2O3 composite coating has a dense structure, and the crystalline is fine.