Table of Content

15 October 2009, Volume 28 Issue 5

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Design of Minerals Composition in Cement Clinker Containing Clacium Sulphoaluminate

MA Su-hua;SHEN Xiao-dong

2009, 28(5):  863-868. 

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The influence of additive on the burning and minerals composition of cement clinker containing calcium sulphoaluminate were researched by chemical analysis and X-Ray diffraction.The results show that the additive must be added in the raw meal for the preparation of the clinker containing calcium sulphoaluminate. The suitable amount of additive can decrease the burning temperature of the clinker containing calcium sulphoaluminate, promote the adopt of f-CaO and improve the burnability of the raw meal. At the relative low temperature (1300 ℃ or 1350 ℃), the clinker containing calcium sulphoaluminate can be preparaed successfully.

Quantitative Characterization for Surface Morphology of Interfacial Transition Zone (ITZ) in Concrete by Fractal Dimension

XU Yan;HU Xiao-fang

2009, 28(5):  869-873. 

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In order to characterize the surface morphology of different kinds of the interfacial transition zone (ITZ) in concrete quantitatively, the fractal dimension was introduced and calculated by the covering projection method. The results show that the surface fractal dimension of the interfacial transition zone in concrete morphology is in the range of 2 to 3, and the correlation coefficients of linear regression analysis are greater than 0.95,and strong correlation indicates that the selected surface of interfacial transition zone morphology has obvious fractal characteristics.

Processes from Gelation, Dry to Sintering of NiO/YSZ Slurry Prepared by Gel-casting

LI Wei;HAN Min-fang

2009, 28(5):  874-880. 

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The NiO/YSZ anode materials made by gel-casting process is one of the hot-spot in the areas of solid oxide fuel cell (SOFC). The effects of initiator and catalyst related to gelation time, temperature to weight loss of green, solid loading percent, type and amount of pore former to the shrinkage of samples and the conductivity of reduced anode were investigated in this paper. The samples were characterized by SEM and EDS. The results show that with 5wt% initiator 2.0 mL and 0.5vol% catalyst 1.0 mL in the 100 mL slurry, the gel time of samples could be controlled within 20 minutes. The best suitable drying temperature of green is 25 ℃. The 45vol% solid loading percent, 15wt% graphite as a pore former, sintering at 1350 ℃, the shrinkage of anode green is matched to that of YSZ. The conductivity of Ni/YSZ anode reduced is 800 S/cm at 600-800 ℃, which could meet the requirement of the conductivity as anode in SOFC.

Gray Correlation Analysis on the Properties of Cement Mortar with the Particle Size Distribution of Clinker and Fly Ash

FU Xiu-xin;PAN Zhi-hua;WANG Dong-dong

2009, 28(5):  881-886. 

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Fly ash cement samples with different specific surface area were prepared from Portland cement clinker and flay ash with different specific surface area. Mortar strength development of the fly ash cement and the particle size distribution of the clinker and fly ash were measured respectively, then the gray correlation analysis was carried out on the properties of cement mortar with the particle size distribution of clinker and fly ash. The results showed that clinker particles with size 0-30 μm correlated with the properties of cement positively, and those with size lager than 30 μm correlated with the properties of cement negatively, among which clinker particles with size between 10-20 μm contributed the most to the strength development of cement mortar. Fly ash particles with size 0- 40 μm correlated with the properties of cement positively, thus being more actively, and those with size lager than 40 μm correlated with the properties of cement negatively, contributed less to the strength development of cement mortar.

Gas Permeation Properties and Synthesis of SAPO-34 Zeolite Membranes by Secondary Growth Method

LI Gang;WANG Jin-qu;YANG Jian-hua;CHU Nai-bo;LU Jin-ming

2009, 28(5):  887-892. 

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SAPO-34 zeolite membranes were synthesized on porous α-Al_2O_3 tubular support by secondary growth method using TEAOH as template. The membranes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and gas permeation tests. XRD patterns showed that the as-synthesized membranes had typical CHA-type zeolite XRD patterns, and no other phase presented. SEM analysis revealed that a thin and compact SAPO-34 layer was formed on α-Al_2O_3 tubular support, the crystals showed well intergrowth, and no pinholes and cracks were observed. At room temperature, with a pressure drop of 0.1 MPa, the ideal and separation selectivity of a SAPO-34 zeolite membrane were 7 and 40, respectively.

Study on Setting Time of Fly Ash-based Geopolymer

JIA Yi-hai;HAN Min-fang;MENG Xian-xian;XU Ze-sheng

2009, 28(5):  893-899. 

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The effects of the ratios of H_2O/FA (fly ash), NaOH/FA, water glass/FA and calcium compounds addition on setting time of geopolymers were investigated. The hardened products were examined by scanning electron microscope (SEM) and the activating solutions were analyzed by nuclear magnetic resonance (~(29)SiNMR). As a result, the final setting times of geopolymers prolonged from 120 min to 280 min as the ratio of H_2O/FA increases from 0.29 to 0.36. The setting time of geopolymer was prolonging with the ratio of NaOH/FA increasing. The trend of compressive strength of geopolymers was the same as that of setting time. When the ratio of NaOH/FA was 0.1, the final setting time sample was longest with 200 min and the compressive strength was highest with 70 MPa. The ratio of Na_2SiO_3/FA has a little effect on setting time. It was found that slag shortened the setting time by providing heterogeneous nucleation centers. The setting time of geopolymers can be adjusted by the ratio of H_2O/FA, NaOH/FA and slag.

Low-silica X Zeolite Synthesized by Two-step Hydrothermal Treatment

WANG You-he;LI Xiang;LIU Wei;YAN Zi-feng

2009, 28(5):  900-904. 

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Low-silica X zeolite (LSX) was synthesized by two-step hydrothermal process with low temperature aging and high temperature crystallization period. The effects of aging temperature, aging time, crystallization temperature and crystallization time were investigated, then the optimal synthesis conditions were obtained. The synthesized sample at optimized conditions was characterized by X-ray diffraction, chemical analysis and N_2 adsorption and desorption. The results showed that the LSX with high puring had low SiO_2/Al_2O_3 ratio and high purity. Its specific surface area reached 503 m~2·g~(-1) and the micropore size distribution curve spread in a narrow range.

Effects of 3Y-TZP Addition on the Mechanical and Electrical Properties of 8YSZ Electrolyte Materials

JIANG Hong;GUO Rui-song;LI Hai-long

2009, 28(5):  905-908. 

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3Y-TZP was added to 8YSZ by means of mechanical mixing in order to first fulfill the need of electrical property as electrolyte and improve its mechanical property. The samples were sintered in air. The effects of 3Y-TZP addition were investigated through the tests of fracture toughness, bending strength, electrical conductivity and phase composition analysis. The results show that 3Y-TZP improves the mechanical property of 8YSZ material. The fracture toughness and bending strength increase obviously with the increase of 3Y-TZP addition and the conductivity of 8YSZ electrolyte materials dope slightly within 0- 30%. The electrical material when the amount of 3Y-TZP reaches up to 30% embodies excellent properties, with an electrical conductivity of 0.11 S/cm at 1000 ℃ and bending strength of 300 MPa.

Effect of Thermostat Burner on the Temperature in Preheating Zone of Tunnel Kiln

XIN Xu-liang;WANG Shi-feng;CHEN Shi-bing

2009, 28(5):  909-912. 

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In order to reduce the temperature difference of tunnel kiln preheating zone from top to bottom, Thermostat burner and temperature distribution was researched by computer numerical simulation. The temperature difference of material zone in preheating zone of tunnel kiln is decreasing when the ratio (1.5%～10%), velocity (60～110 m/s) and temperature (0～500 K) of flame gas injected are increasing if the thermostat burner's other operation parameters are fixed. Burner thermostat suitable arrangement is staggered.

Numerical Simulation and Analysis of the Effect of the Mould with Temperature Gradient on Solid-liquid Interfacial Position in the Preparation of Sheet Copper Tube by Downward Continuous Unidirectional Solidification Method

SHEN Xi;ZHANG Hong;WANG Zi-dong;LOU Hua-fen;HU Ping-xia

2009, 28(5):  913-918. 

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Based upon the principle of downward continuous unidirectional solidification (DCUS) in the preparation of sheet copper tube, the physical and mathematical models of two-dimensional steady heat transfer for temperature field are established. By contrast the effect of process parameters on solid-liquid interfacial position with different type of mould, the calculated results show that it could get reletively wider process paremter range and higher casting speed at the steady melt temperature by using the mould with temperature gradient.

Study on Improving Rupture Strength and Surface Hardness of Set Gypsum

MENG Li-feng;LIU Dong-hui;WANG Chuan-ping

2009, 28(5):  919-925. 

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The rupture strength and surface hardness of set gypsum was studied by doping in additive agents as calcium hydroxide、melamine、polyvinyl alcohol、reactant addition agent. The dose of each additive reagent was investigated. The rupture strength was slightly reduced while surface hardness was increased during the increasing dose of calcium hydroxide varied from 0 to 10%. The rupture strength was the highest when the dose of melamine was 2%. The surface hardness was best when the dose of melamine was 4%. The appropriate dose of polyvinyl alcohol was 0.8%. It was demonstrated that the trend of rupture strength and surface hardness of set gypsum was opposite when the dose of reactant addition agent increased from 3%. The SEM shows that the morphology and arrangement of the dihydrate gypsum crystal have been apparently changed by the influence of additive agents. The shape of the micro-crystal was almost needle-like and cylindrical. The rigid net structure has been formed by crossed micro-crystal and the arrangement of crystal has been in order. The gas-pocket structure has been dispersed homogeneously. Accordingly, high rupture strength and surface hardness of the set gypsum have been obtained.

Photocatalytic Activity of Titania Nanowire Arrays Co-doped with Neodymium and Fiuorin

ZHANG Shao-hua;WANG Jian-jun;HU Jiang-feng;XIE Bing

2009, 28(5):  926-929. 

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Titania nanowire arrays were synthesized in highly ordered porous anodic alumina template by Sol-gel electrophoretic method.The samples were characterized by SEM and XRD. The photocatalytic properties of Nd~(3+)/TiO_2，F~-/ TiO_2 and Nd~(3+)/F~-/TiO_2 nanowire arrays were characterized by degradation of methyl orange solution. The results show that Nd~(3+)/F~-/TiO_2 nanowire arrays exhibit higher photocatalytic activity than that of Nd~(3+)/TiO_2 and F~-/ TiO_2 nanowire arrays. For Nd~(3+)/F~-/TiO_2 nanowire arrays，the degradation rate of methyl orange exceeds 90% after 1 h irradiation. At the same time，the absorption wavelength of TiO_2 film shifts red with the addition of impurity ions, indicating that the nanowire arrays exhibit some photocatalytic activity in visible spectrum.

Effects of MoSi_2 Additive on the Properties of HfB2 Ultra High Temperature Ceramics Produced by Gel-gasting

TANG Zhu-xing;YANG Qing-qing;YANG Zan-zhong

2009, 28(5):  930-934. 

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The green bodies of the HfB_2-(5%-15wt%) MoSi_2 ultra high temperature ceramics (UHTCs)system were produced by gel-casting when pH was 10.9, the content of dispersant（PMAA-NH_4）was 8vol% and the solid content of the slurry was 40vol%. the density of the green bodies had achieved above 4.25 g/cm~3 . They were sintered in a high multi-furnace under a flowing argon atmosphere at 1950 ℃ for 30 min. The effects of MoSi_2 additions on the properties of HfB_2 UHTCs were studied. The phase compositions were analyzed with an X-ray diffractometer and the microstructures of the sintered UHTCs were studied by SEM. The results show that the densification and the mechanical properties of the HfB_2 UHTCs added with the increase of MoSi_2 were improved highly. When 15wt% MoSi_2 were added, the hardness of the HfB_2 UHTCs reached 9.8 GPa, the bending strength reached 389.7 MPa and the fracture toughness reached 3.7 MPa·m~(1/2).

Study on Synthesis and Photocatalytic Activity of Porous Ag-ZnO Catalyst

JIA Zhi-gang;LI Yan-hua

2009, 28(5):  935-939. 

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Porous Ag-ZnO catalyst was synthesized by calcining the mixed metal oxalate precursor and subsequent exposure in air. The photocatalytic activity under ultraviolet light was evaluated by photocatalytic degradation of methyl orange.The reaction mechanism was also studied. The experimental results show that the photocatalytic activity was influenced by the calcination temperature, calcination period and the heating-up rate. The slower heating-up rate and the longer calcination period were favor of the improvement of photocatalytic activity, while the photocatalytic activity decreases with the higher calcination temperature. The difference of photocatalytic activity for the complex catalysts with exposed period was related to the variation of Ag phase in air. The optimum catalyst was obtained by calcining the precursor doped 4% Ag at 450 ℃ for 6 h at the heating-up rate of 5 ℃/min and subsequent exposure treatment for 6 d in air.

Study on In-situ Polymerization of Polyacrylonitrile/Montmorillonite

JIA Zhao;TIAN Gui-shan;YANG Yan-gong

2009, 28(5):  940-943. 

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Organized montmorillonite(O-MMT) was prepared using cetyl trimethyl ammonium bromide(CTAB). With ammonium persulfate as the initiator, Polyacrylonitrile (PAN) was made by in situ polymerization between the layer of O-MMT. The structure of PAN/MMT was characterized by Fourier transformed infrared spectroscopy (FT-IR) and X-ray diffractometry (XRD). Both the flame retardant property and heat resistanct were investigated. FT-IR and XRD indicated that the interlay spacing of MMT has been expanded, which was attributed to the fact that PAN has been intercalated into the layer by in situ polymerization. The LOI of the blend was enhanced from 18% to 22%, which revealed that the flame retardant property has been improved. In addition, the heat resistanct has been improved.

Preparation and Photocatalytic Properties of Mo-doped TiO_2

CHEN Gui-hua;YAN Rui-qiang;LIANG Hua-ding;YANG Hui

2009, 28(5):  944-950. 

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The pure TiO_2 and Mo-doped TiO_2 nanoparticles were prepared by Sol-gel method with tetrabutyl titanate as raw material and characterized by XRD, UV-VIS and XPS. The photocatalytic activity was investigated by degradation of methylene blue. Effects of calcined temperature and doping content of Mo on crystal lattice distortion, grain size, crystal phase, optical properties and photocatalytic activities were investigated. The results show that most of Mo~(6+) takes the place of Ti~(4+) in the crystal lattice of TiO_2, which leds to distortion of crystal lattice, restrains the increase of grain size and inhabits the phase transformation from anatase to rutile of TiO_2. Exciation wavelength red shift more with doping more Mo content calcined at 450 ℃. The content of anatase phase in 1.8%Mo-TiO_2 mixed crystal calcined at 600 ℃, and inducing exciation wavelength blue shift. Doping with the appropriate content of Mo improves the photocatalytic activity of TiO_2, the photocatalytic activity of 1.8%(in mole) Mo doped TiO_2 nanoparticles is optical calcined at 600 ℃.

Study on the Antimicrobial Properties of Ag-carrying Montmorillonite

ZHAO Bing;WU Xin;WANG Guo-qing

2009, 28(5):  951-954. 

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The antibacterial properties of Ag-carrying montmorillonite against colon bacillus, staphylococcus aureus, gas bacillus, hay bacillus, brewer's yeast and candida albicans were confirmed by test-tube experiment oscillation, meanwhile the water resisting property and durability experiment of Ag-carrying montmorillonite were also investigated.The results show that this kind of material reveals effectively bacteriostasis and disinfection ability when the the content of Ag carried on montmorillonite amounts to 2.5%-3.40%. Ag-carrying montmorillonite possesses broad-spectrum antibacterial property. It is not easily decomposed and becomes invalid. Moreover，the antimicrobial agent is long lasting and exhits good water-resisting property.

Experimental Study on Mechanical Property of Basalt Fibre Reinforced Concrete

PAN Hui-min

2009, 28(5):  955-958. 

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More attention is focused on experimental research on basalt fiber at home and abroad. Through the experiments research on the compressive properties,the flexural properties and the flexural impact behavior,the effects of mixing amount of fibers on the mechanical properties of concrete were studied. And the best mixing amount of fibers was obtained. The results show that the strength and the flexural impact behavior can be improved by means of adding basalt fiber into concrete.

Small-angle Scattering Technique and Its Application in Microstructure Characterization of Hardened Cement Pastes

SHEN Ye-qing;DENG Min;MO Li-wu

2009, 28(5):  959-964. 

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This paper summarizes the principal theory of small-angle scattering technique (SAS), including Guinier approximation, Porod approximation and function of the two approximations. Application of SAS in nano-CSH particle diameter, fractal structure of nano-CSH and pore structure distribution in hardened cement pastes is also described in the paper. Advantage of the technique is nondestructive, noninvasive, and could be used repeatedly in the real-time characterization of the microstructure and its evolution. SAS, especially small-angle neutron scattering technique (SANS), also has its limit because effective neutron source is difficult to obtain, analysis of test model is too simplistic far from real fact, and experiment is costly and non-portable.

Research Progress in Silicon-based (oxy) Nitride Phosphors for White LED

ZHAO Xin-ran;FU Ren-li;SONG Xiu-feng;ZHANG Shao-dong;PAN Zheng-wei

2009, 28(5):  965-972. 

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The structures of silicon-based (oxy) nitrides are generally built up of networks constructed from linked SiX_4(X=O,N) tetrahedra. The silicon-based (oxy) nitride phosphors had been considered as promising down-conversion phosphors for white LED owing to their high thermal and chemical stability, and excellent photoluminescence properties. The chemical composition and structure, luminescence properties and improvement methods of silicon-based (oxy) nitride phosphors systems were well summarized. At last, the development and application in white LED of the silicon-based (oxy) nitride phosphors were indicated.

Research Progress in Microwave Property and Preparation of Barium Hexaferrite

CHEN Yu-wei;DENG Min;XIONG Guo-xuan

2009, 28(5):  973-979. 

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As a novel magnetic material, barium hexaferrite had been widely used, especially using as microwave absorbing material. This article reviewed how to improve BaM microwave absorb property,such as doping metal ions, controlling particle morphology and size. Through doping metal ions in BaM or reducing particle size, the natural resonance could be shifted to low frequency. The opposite result could be got if the morphology of BaM is one-dimension.The synthesizing methods for barium hexaferrite, such as conventional ceramic, sol-gel, reverse micelle, hydrothermal and co-precipitation, were also presented. We analysed all these methods merits and faults.

Research Progress in Technology and Equipments of Energy-economize and Contamination-control in Cement Industry

TAO Cong-xi;ZHAO Lin;YU Wei-min;HU Zhi-juan;CHAI Xing-teng;ZHANG Fu-bin

2009, 28(5):  980-985. 

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The research progress in the new technology and equipment used in the Chinese cement industry to realize energy saving and emission reduction was reviewed. The technology and equipment involved in the high efficient and energy-saving clinker burning system, the high efficient and energy-saving grinding system, the power generation process using waste heat from pure cryogenic gas and the solid hazardous wastes disposal process in the cement kiln were discussed, which can realize energy saving and emission reduction in the cement production process.

Research Progress in Preparation and Electric Properties of (Zr, Sn)TiO_4 Thin Films

CHEN Fei;ZHOU Hong-qing;ZHU Hai-kui;WEI Peng-fei;CHEN Dong;LIU Min

2009, 28(5):  986-990. 

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From the piont of the increasing requirement on the performance of thin film materials, the crystal structure, preparation technologies, electrical properties of (Zr, Sn)TiO_4 thin films were mainly summarized. It was proposed that the preparation methods would be extended and modified. And the reserch focus was also pionted out.

Research Progress in Perovskite-like Cathode for Intermediate Temperature Solid Oxide Fuel Cells

GUO You-bin;LU Li-hua;CHU Ling;ZHANG Hua;JIN Jiang

2009, 28(5):  991-996. 

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The composite oxide with perovskite-like structure developed in these years could be a promising cathode of IT-SOFC. In this paper, the research progress of A_2BO_4-type and AA' B_2O_5-type perovskite-like cathode materials was reviewed, and summarized the property of the two types of materials as IT-SOFC cathodes. Improving the microstructure and enhancing the electrochemical performance and thermal stability for perovskite-like cathode will be the emphases for future's research.

Application of Piezoelectric Ceramic Materials on Display Technology

ZHOU Jing;SUN Hai-bin;LIU Jun-cheng

2009, 28(5):  997-1001. 

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The working principle of piezoelectric ceramic displays was described in this paper. Utilizing the inverse piezoelectric effect, the piezoelectric ceramic display takes piezoelectric actuator as its pixel driving source. The preparation processes of piezoelectric ceramics were introduced and the available ceramic materials for display were analyzed. Finally, key technologies restricting the development of ceramic displays were discussed.

Research Progress in the Stugy of Alumina Aerogels

HU Zi-jun;ZHOU Jie-jie;CHEN Xiao-hong;SUN Chen-cheng

2009, 28(5):  1002-1007. 

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Alumina aerogel had been paid great attention for its unique properties. The structure and various preparation methods of alumina aerogels had been summarized in this paper. The preparation methods included alumina alkoxide one step,two steps method and addition of propylene oxide method. The addition of propylene oxide method is one of the most potential route for the synthesis of high performance alumina aerogels. Fiber-reinforced, multiple cornponent and doped aerogels were also introduced.

Research Progress in the Synthesis of Zeolite from Fly Ash

ZHAO Ya-juan;ZHAO Xi-cheng;JIANG Yuan-ru

2009, 28(5):  1008-1012. 

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This paper provided an overview on the methodologies for zeolite synthesis from fly ash (FA),and a detailed description of conventional alkaline conversion processes,with special emphasis on the experimental conditions to obtain different zeolite types. Zeolitic products could be obtained from FA by direct conversion and two-step conversion. A review of potential applications of different zeolitic products for waste water was also given. The examination of the data presented by different authors reveals that one of the main potential application of this material is the uptake of heavy metal ions from polluted waste waters. The adsorption capacity was different according to zeolites type. A new direction with zeolite synthesized from FA is gived.

Research Progress in Antiperoviskite Negative Thermal Expansion Mn_3XN

CHEN Guang-le;FAN Shi-gang;PENG Zhen-zhen

2009, 28(5):  1013-1017. 

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A large magnetostriction in an antiperoviskite system, Mn_3XN, is well-known for their large magnetovolume effect. The relation of magnetic transformation and negative thermal expansion was discussed. The contrastive difference of several Mn_3XN system was summarized, and the diversification of the linear thermal expansion with different element replacement was analyzed. It is proposed with a view to practical applications and further experiment.

Application of Optical Basicity in Glasses and Its Relationship with Element Properties

QI Ji;WANG Cheng-yu;NING Gui-ling

2009, 28(5):  1018-1023. 

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Optical basicity is a scale for acidity and basicity, a reflection of structure and has significant effects on chemical and physical properties of glasses. In this paper, the conception, experimental determination and theoretical computations of optical basicity of glasses were introduced. The relationships between optical basicity and electronegativity of elements, polarizability of oxide ion, O1s binding energy in glasses were reviewed. The qualitative and quantitative relationships between optical basicity and other parameters were discussed and analyzed. The nature and dependence parameters of optical basicity were concluded. It was also prospected that the further researches possibly focus on application and the correlations of optical basicity in different glass systems.

Effect of Fluorine Content on Crystallization of CaO-SiO_2-R_2O-F Glass-ceramics

ZHOU Xi-ya;HU Jun;ZHOU Bin-yang;LIU Lin-feng

2009, 28(5):  1024-1028. 

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CaO-SiO_2-R_2O-F(R=Na,K) glass-ceramic were prepared by sintering method in this paper. Influence of nucleation agent CaF_2 on the crystallization behavior of canasite ceramic glasses had been investigated using differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicate that CaF_2 can effectively prompt full crystallization. By means of suitable heat treatment, canasite glass-ceramics can be obtained with a randomly-oriented interlocking blade-like crystals and acicular crystals. The major crystalline phases of the glass-ceramics are canasite and Frankamenite (a fluorine-rich form of canasite). With the increasing of the fluorine concentration, both the content and the number of crystalline phase increase,and the grain size decrease.

Mechanism of Brittle-ductile Transition of Glass-ceramics at Low Temperature

ZHOU Liang;ZUO Dun-wen;SUN Yu-li;ZHU Yong-wei

2009, 28(5):  1029-1032. 

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Glass-ceramic is a new kind of substrate for hard disk of computer. In recent years, the mostly used ultra-precision machining methods are lapping and polishing. In this paper, the mechanism of brittle-ductile transition of glass-ceramics at different low temperatures was studied. Formation, propagation,length of crack and hardness of glass-ceramics were investigated at different temperature by means of Vickers indentation. The effect of temperature on the mechanism of its brittle-ductile transition was analyzed. Results show that with the increase of load at different temperatures, glass-ceramic goes through the ductile to brittle transition. Besides, with the decrease of temperature its hardness increases gradually,and the length of crack decreases.

Reaction Mechanism and Low Temperature Synthesis of α-ZnS Nanoparticles by a Sonochemical Process

LI Ji-rong;HUANG Jian-feng;CAO Li-yun;HE Hai-yan;WU Jian-peng

2009, 28(5):  1033-1037. 

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Wurtzite zinc sulfide (α-ZnS) nanocrystallites were synthesized successfully by a sonochemical process using zinc chloride and thiacetamide as raw materials. The as-prepared ZnS nanocrystallites were characterized using X-ray diffraction (XRD), differential scanning calorimetry (DSC), transmission electron microscopy(TEM) and selected area eletron diffraction (SAED). Results show that the as-prepared ZnS nanocrystallites are in hexagonal structure with sphere morphologies and the particle size is about 20-30 nm. The three diffraction rings in the SAED image could be identified corresponding to the crystall face of (002), (110) and (112) of α-ZnS, respectively. Researching on the reaction mechanism indicates that under the ultrasonic irradiation, simonkolleite (Zn_5(OH)_8Cl_2·H_2O) is generated firstly in the reaction system, which is in a hexagonal structure, and it provides a good template for the growth of α-ZnS nanoparticles.

Sulfate Resistance of Alite-barium Calcium Sulphoaluminate Cement

LI Gui-qiang;LU Ling-chao;WANG Shou-de;CHEN Cheng;YIN Chao-nan

2009, 28(5):  1038-1041. 

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Effect of gypsum content on the sulfate resistance of alite-barium calcium sulphoaluminate cement was investigated. Portland cement was taken for comparison. The composition and microstructure of hardened cement pastes were analyzed by X-ray diffraction and scanning electron microscope. The results show that alite-barium calcium sulphoaluminate cement has better ability of sulfate resistance. The coefficient of resistance to sulfate attack with 5% gypsum addition in alite-barium calcium sulphoaluminate is 1.31, while that in Portland cement is only 0.94. Gypsum can affect the tightness of alite-barium calcium sulphoaluminate cement hardened pastes and further influence the ability of resistance to sulfate attack. At the same time, the mechanism of sulfate resistance of alite-barium calcium sulphoaluminate cement was discussed in this paper.

Study on Durable Experiment of Recycled Aggregate Concrete Used by Solid Waste

CUI Zheng-long;KITATSUJI Masa-humi;TANAKA Rei-ji

2009, 28(5):  1042-1045. 

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Strength grade C30 of recycled aggregate that was one of effective methods to dispose waste solid was fabricated with Ca series expanding agent, and blast furnace slag cement and low absorption recycled aggregate used to restrain alkali-aggregate reaction.The durable experiment shows that the strength and durability compared ordinary concrete with recycled aggregate concrete both display the same properties and Ca series expanding agent, blast furnace slag cement, and small water absorption play a good effect on durability of recycled aggregate concrete.

Research on Structure and Properties of Nature Basalt Coating with Atmospheric Plasma Spraying

ZHAO Min;DING Xiang-qun;ZHANG Yun-feng

2009, 28(5):  1046-1049. 

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Basalt was used to produce powder, then the powder was used to spray on steel and aluminum plates with APS technology in order to create a new mineral coating. The powder of basalt appeared prismatic structure. Powder was mainly composed of SiO_2,K_2O,CaO,Fe_2O_3,Al_2O_3 and the size of them was in 80-200 μm range. The flowability of powder was better. The structure of coating was analysed by SEM and X-ray diffraction methods. The result of experiment shows that there are some holes and micro cracks on surface of coating and structure of coating is amorphous. The bond of coating with intermediate layer is better. The max thickness of coating is about 134 μm and micro hardness of coating is 593-928 Hv_100.

Study on Infrared Spectra of ZnO-B_2O_3-SiO_2 Glass

ZHANG Ming-xi;LI Feng-feng;ZHANG Lin;SHEN Yi;Charles Christopher Sorrell

2009, 28(5):  1050-1054. 

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Glass structures with different components of ZnO-B_2O_3-SiO_2 were investigated by using the Fourier transform infrared spectra. The relationship between the glass structure and components was also analyzed. The results show that when concentration of ZnO is greater than 30%, Zn2+ entered into B-O-Si net, Zn-O-B bond and Zn-O-Si bond are formed and when concentration is greater than 40%, [ZnO_4] units are formed. Otherwise, [BO_3] units are changed into [BO_4] units with the increasing of ZnO content.The growing of SiO_2/ B_2O_3 ratio also introduces the increment of Zn-O-B bonds, Zn-O-Si bonds and [ZnO_4] unitses.At the minetime, [BO_3] unitses also turn to[ BO_4]unitses, and they tend to form boron oxygen polymer groups.

Effect of Mineral Admixture on Acid Resistance of Portland Cement and Mix Design

QIAO Lin;WANG Qi;TIAN Lu-fei;LIU Zhen

2009, 28(5):  1055-1059. 

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Silica fume, fly ash and slag were chosen as mineral admixture， the influence of mineral admixture on cement hydration products, structure and morphology of hardened cement paste were analyzed by means of SEM and XRD. The mechanism of acid corrosion to cement was discussed and proportion optimization of mineral admixture was carried on to improve the acid resistance of portland cement. The results show that mineral admixture is beneficial to reduce alkalinity and improve the pore structure of hardened cement paste. When silica fume, fly ash and slag accounted for 5%, 10% and 15% of cement separately are introduced together, the acid resistance of portland cement is the best.

Effect of (SrZrO_3)_(10)(SrTiO_3)_(90) Buffer Layer on the Crystallization and Ferroelectric Properties of PbZr0.52Ti0.48O3 Thin Films

XIN Hong;SU Wei-an;WANG Yan-yang

2009, 28(5):  1060-1063. 

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PbZr_0.52Ti_0.48O_3 (PZT) thin films were prepared by a Sol-gel method with (SZO)_(10)(STO)_(90) buffer layer. The effect of (SZO)_(10)(STO)_(90) buffer layer on the crystallization and ferroelectric properties of PZT thin films was investigated. X-ray diffraction patterns show that the crystallization of PZT thin films varies with buffer layer clearly. (SZO)_(10)(STO)_(90) seeding layer almost results in the formation of a single (111)-textured PZT film, and (111)-orientation degree increases from 45.0% to more then 90.1%. At the same time, ferroelectric properties of the PZT thin film are improved by (SZO)_(10)(STO)_(90) seeding layer, remanent polarization increases from 26.8 μC/cm~2 to 38.8 μC/cm~2.

Research on Titanium Gypsum for Light-quality Wall Material

QU De-ye;WANG Jun

2009, 28(5):  1064-1070. 

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The article discusses the technique of using titanium gypsum frying to alter the nature of gypsum and produce light-quality wall material. DSC,XRD and SEM, together with other ordinary chemical and physical methods, are applied to test the physical properties of titanium gypsum after frying,according to the gypsum standard of P.R.C. With different temperatures and admixtures, the physical properties of the titanium gypsum are influenced. The results show that the strength of the titanium gypsum changed with the rise of the frying temperature and the best temperature is 170 ℃。Admixture-adding made a change in strength of the titanium gypsum. The best added amount is as follows: concrete 8%-12%, lime 1%, calcium lignosulfonate 0.4%-0.5%. Meanwhile the micro-structure of the titanium gypsum changed from being elongated and tabular to flocculated. Body of the titanium gypsum was fattened and the tissue also changed greatly.

Influence of Nano-TiO_2 on the Surface Structure of the Ceramic Glaze

ZHOU Wu-yi;ZHANG Wei

2009, 28(5):  1071-1075. 

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In this paper,a modificative glaze was prepared using nano-TiO_2 as the additive which resulted in sintering quickly at low temperature. The structure and configuration of the glaze were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared spectrum (IR). The results show that nano-TiO_2 could combined well with silk screen printing glaze and a looked flat, compact, lubricity and reflect ivory-white glaze is obtained by using 5-7.5wt% of nano-TiO_2 and calcining at 750-800 ℃.

Study on the Structure and the Characteristic of Attapulgite Modified by Calcium Carbonate Compound Powder

ZHAO Di-fang;HAN Cheng-liang

2009, 28(5):  1076-1079. 

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Incorporate the attapulgite and the system of Ca(OH)_2-H_2O-CO_2, the composite powder of attapulgite modified by calcium carbonate used the method of heterogeneous nucleation were prepared. The whiteness, distribution of particle size, the phase constitution and the microscopic pattern were tested and analysed.The results show that the whiteness of attapulgite has raised from 71.13 to 93.37, the average particle size D90 decreases rapidly from 244.620 μm to 22.091 μm and the size of calcium carbonate particle is 30-40 nm. The formation mechanics of composite powder were discussed.

Research on the Thermal Storage and Heat Release System in Sandwich Wall Phase-change Insulation Layer

SHANG Jian-li;WANG Zheng-jun;WU Qiang;YANG Guang

2009, 28(5):  1080-1083. 

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According to the technology of thermal storage and the characteristics of energy-saving wall,a new vision of Sandwich composite wall was proposed.By this vision,phase change materials worked as heat-driven source,setting of materials, construction, building as a whole.And based on the heat transfer theory,the process of laminated phase change materials which release heat in winter,storage thermal in summer was analysed. The result shows that the complex system have double effect on self-thermostat and energy-saving.

Preparation of Composite Water Reducer of Refractory Castable

WANG Hai-juan;LIAO Jian-guo;NIU Guo-qing

2009, 28(5):  1084-1087. 

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Based on the results of three kinds of water reducer solely added in refractory castable, and orthogonal test was used to determine the optimal mix ratio. According to the seven performance indexes of castable and result of analysis of scanning electronic microscope, optimal admixing quantity of composite water reducer was obtained. Exprimental results show that the water reducer has evident effect on water reducing, and the performance of refractory castable improves greatly when composite water reducer is in the the scope of 5‰-10‰.

Densification of Machinable Fluoramphibole Glass-ceramics Prepared by Reactive Crystallization-sintering

ZHANG Wei-yi;GAO Hong;ZHANG Li-ming

2009, 28(5):  1088-1092. 

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The sintering of powder compacts of fluormica and soda-lime glass was performed by two types of heating schedules. The densification behaviors of the glass-ceramics were studied by means of the observation of their microstructural evolution using scanning electron microscopy and the measurement of the changes in the shrinkage and density of the compacts during sintering. The results show that the densification of glass-ceramics is achieved by the viscous flow of glassy　phase, the fluormica addition inhibites the viscous flow of glassy phase and reduces the driving force of sintering. Heating up to 850 ℃, fluoramphibole is formed by a reactive crystallization between fluormica and glass,which had a significant influence on the densification. The density of glass-ceramics increases with sintering temperature and isothermal time before the reactive crystallization, but decreases slightly after it because a dense interlocked rod-like fluoramphibole crystal skeleton formes gradually and seriously retards the viscous flow of glassy phase.

Synthesis of Aluminum Oxynitride Powder by Carbothermal Reduction Method

TIAN Ting-yan;DU Hong-bing;JIANG Hua-wei;SUN Feng;ZHANG Wei;FENG Zhi-hua

2009, 28(5):  1093-1096. 

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Aluminum oxynitride powders (ALON) were synthesized by carbothermal reduction method using γ-Al_2O_3 and activity carbon as raw materials. The rate of γ-Al_2O_3 and activity carbon, synthesizing temperature, holding time and removal of carbon impurity were studied in this paper. The prepared powders were analyzed by XRD and SEM. The results showed that ALON powders had well-developed crystal and homogenous granularity.

Application of Fly Ash-acetylene Sludge-sodium Sulfate Concrete in Rural Highway

XIAO Lin-jun;LI Li-min

2009, 28(5):  1097-1101. 

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The application of PLS concrete in rural highway can not only greatly reduce the engineering cost and solve the fund problem of rural highway construction, but also solve the problem of fly ash - acetylene sludge disposal. At the same time, it is advantageous to environmental protection. Combined with the test road, the mixture ratio design, key road performance and construction technique of PLS concrete are studied, which can be taken as a reference for valuable experience to the wide application of PLS concrete on rural highway in our country.

Method for Identifying Asbestos in Brake Rubber of Bicycle

FENG Ya-hui;LI Jian-jun;CHENG Wei;LU Zhi-gang;ZHANG Mei;ZHENG Jian-ming;XU Xin-chun

2009, 28(5):  1102-1106. 

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A method of identification for low content chrysotile, crocidolite and amosite in brake rubber of bicycle by the united way of polarized light microscope and X-ray diffraction had been established. The preliminary break of sample, conditions of low temperature plasma incineration and compare with ashing efficiency in electric furnace, identification of asbestos using polarized light microscope and X-ray diffraction were studied, and the ruler of judging the exist of asbestos was ensured.