Table of Content

15 February 2010, Volume 29 Issue 1

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Effect of Curing Temperature on the Hydration Products Composition of MgO Calcinated at High Temperature

WANG Guo-qiang;LI Xiao-yun;QIU Tai

2010, 29(1):  1-5. 

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Hydration properties and hydration products of light magnesium oxide were investigated under different experimental conditions by means of TG-DSC and TG-FTIR. The results show that magnesium oxide calcinated at 900 ℃ tends to hydrate even at ambient temperature. Hydration can be significantly accelerated with increasing temperature. Under the atmospheric pressure and high humidity, hydration and carbonation were both exist when MgO was calcinated at 1300 ℃. The productions of reaction are hexagonally Mg(OH)_2 and amorphous carbonate. Production quantities of these two kinds of product increase obviously along with rising of curing temperature. Pyrolysis temperature of the carbonate generating in this experiment is within 300-450 ℃, which almost covering up the range of decomposition temperature of hexagonal Mg(OH)_2. After calcinated at higher than 1300 ℃, MgO has a great stability that it hardly react with H_2O or CO_2 at room temperature. But it still tends to hydrate and carbonate when curing temperature rises up to 40 ℃ or higher.

Study on Lapping of K9 Glass by Fixed Abrasive Pad

LIN Kui;ZHU Yong-wei;LI Jun;LI Mao;ZUO Dun-wen

2010, 29(1):  6-11. 

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In order to improve lapping efficiency and quality of optical materials, a method of hydrophilic fixed abrasive pad (FAP) lapping was introduced. The fixed abrasive pad embedded with diamond abrasives which had a diameter of 5-10 μm was developed through pattern transfer and UV-curing process. Material Removal Rate (MRR) and average surface roughness (Sa) were employed to evaluate the performance of lapping or polishing. The conventional lapping, fixed abrasive pellet lapping, and hydrophilic FAP lapping of K9 glass with the same particle size abrasives were compared. Results show that the MRR of hydrophilic FAP lapping is 350 nm/min and the average surface roughness Sa is 3.24 nm. Both of the two parameters achieve the quality of finish lapping and polishing. Material removal models of fixed abrasive pellet and hydrophilic FAP are concluded through the experiment results. Besides, self-conditioning mechanism of hydrophilic FAP lapping is obtained.

Synthesis and Characterization of Polyethy Leneglycol-mesoporous Silica Composites

ZHAO Na;WEI Kun;CHEN Xiao-feng;LI Xiang;GUO Wu-sheng;SHU Li-jun;WU Yuan;ZENG Xiao-feng

2010, 29(1):  12-16. 

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Polyethy leneglycol-mesoporous silica was synthesized successfully using impregnation method.The samples were characterized by XRD,N_2 ab-desorption,SEM、infrared spectroscopy(FTIR),DSC-TG. The results of XRD demonstrated that polyethy leneglycol-Mesoporous silica composites kept mesostructure. The results of SEM showed that Polyethy leneglycol-mesoporous silica can be dispersed into mesoporous silical material. The infrared adsorption spectrum analysis showed that the adsorption between the polyethylene glycol and HMS was formed by hydrogen bonding, between which no chemical reactions occurred. From the TG analysis can be seen that the polymer has good heat resistance, HMS enhanced the heat-resistant of the polymer.

Preparation and Characterization of Ag/SiO_2 Composite Grains by Sol-gel Technology

LI Gui-an;DENG Zhong-xun;JIAO Fei;ZHANG Ya-juan;ZHU Ting-liang

2010, 29(1):  17-20. 

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The silver-silica composite grains with different structures were prepared by Sol-gel technology. The formation mechanism was analyzed, the structures of composite grains were characterized by transmission electron microscope (TEM), scan electron microscope (SEM), X-ray diffraction (XRD),Fourier transform infrared spectrometer(FT-IR) and ultraviolet-visible spectroscopy(UV-Vis). The results indicated that the average size of composite grains(290 nm) was homogeneous and the form was similar to sphericity; and Ag grains(4 nm)which were linked on the surface of silica were also homogeneous distribution. In addition, the distribution of Ag grains on the surface of silica were affected by silane coupling agent KH-550, the network system of silica Si-O-Si was affected definitely by silane coupling agent KH-550 , which controled effectively the cluster degree of composite grains.

Research on the Synthesis and Microstructure of Layered-ternary Nitride Ti_4AlN_3

TAN Qing;MEI Bing-chu;ZHOU Wei-bing;WANG Jing-ping

2010, 29(1):  21-25. 

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Predominantly single-phase bulk samples of Ti_4AlN_3 with a few amounts of TiN and Al_3Ti was successfully synthesized by a hot-pressing method using Ti, Al and TiN powders as starting materials. The phase composition of the sintered samples with different starting composition, sintering temperature and holding time were presented. The results of BEI and EDS show that Ti_4AlN_3 is synthesized with the initial composition of Ti/1.2Al/3TiN at 1400 ℃ for 2 h.The sintered sample is fully dense and well-developed in laminate shape with dimension of 5-10 μm. The relative density of it reachs to 99.3%. Besides, the Vickers hardness and electrical conductivity are 3.4-4.5 GPa and 1.2×10~6 Ω~(-1)·m~(-1), which performs well on machinability and electrical property.

Intercalation Mechanism of Configuration of Potassium Carbonate System in the Bentonite Interlayer

ZHOU Ying;LIU Hong-jie;ZOU Rong;YI Mei-gui;LIANG Yu-xiang

2010, 29(1):  26-32. 

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This paper studied on the reaction between sulfuric acid and potassium carbonate in the bentonite layer to potassium sulfate for crystalline in the layer. The optimum experimental conditions were as follows:water bath temperature is 80 ℃,stirring speed is 1.5 m/s, stirring time is 30 min, concentration is 20 g bentonite slurry dissolved in distilled water whose volume is 100 mL; sub-water bath temperature is 70-70 ℃, sub-stirring speed is 0.5-2.0 m/s.The results of single factor experiments and orthogonal experimental are anastomosis. Order of its factors: stirring speed> pulp concentration > water temperature> stirring time. Its best crystallization of layers achieve is 4.2 g. The SEM, EDS picture shows the success of the crystallization of potassium sulfate in the bentonite layer space. The phenomenon of package isn' t appear,so it's a better understanding for releasing of fixed potassium.

Synthesis and Characterization of La_(0.7)Sr_(0.2)Co_(0.1)CuO_(3-σ) Cathode Materials for IT-SOFC

LI Zhao-hui;HOU Shu-en;PANG Song

2010, 29(1):  33-37. 

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Perovskite-type ultrafine La_(0.7)Sr_(0.2)Co_(0.1)CuO_(3-σ) powders used as cathode materials for intermediate temperature solid oxide fuel cell (IT-SOFC) were directly synthesized by a citrate process and the microstructure was observed with scanning electron microscopy (SEM) and analyzed by DSC-TG、XRD. Baking the precursor at different temperature in order to get the powder with different specific surface area. Using semi-dry method to sharp the LSCC and test electrical conductivity in intermediate temperature. The results indicate that high purity ultrafine LSCC powder can be synthesis by citrate process and self-combusting method and it shows good electrical conductivity(more than 150 S/cm), output power(0.85 W/cm~2 and activation energy(112.1 kJ/mol)in suitably temperature.

Preparation and Compressive Strength of Red-mud and Fly Ash Based Non-sintering Geopolymer

LI Wen-juan;GONG Meng;HUANG Zhao-hui;FANG Ming-hao;LIU Yan-gai

2010, 29(1):  38-42. 

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The high early compressive strength geopolymer is prepared by using red-mud and fly ash as the main raw materials, adding suitable water glass as alkali exciting agent. Influence of alkali exciting agent to the development of compressive strength of the samples was discussed in this paper. The non-sintering materials were prepared by using silver sand as the aggregate cementing with red-mud and fly ash geopolymer. When adding amounts of red-mud are between 60%-70%, the compressive strength of all samples in the third day is higher than 10 MPa, they satisfy the demand of MU10 high quality for free-bearing wallboard materials. The mechanism of cementing reaction is also discussed briefly.

Study on Potassium Sulfate Crystal by Method of Ammonia Sulfate and Slow-releasing in Bentonite

LIU Hong-jie;ZOU Rong;ZHOU Ying;LIANG Yu-xiang

2010, 29(1):  43-48. 

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The optimum of technological conditions of potassium sulfate crystal by method of ammonia sulfate and slow-releasing in bentonite were studied.The whisker of potassium sulfate is grown after adding the surfactant M. The optimum conditions is :the ratio of (NH_4)_2SO_4∶ KCl=1.1∶ 1; stirring rate:2.0 m/s; stirring time:80 min; pulp density:25 g/100 g; concentration of ethanol:20%. We know that the potassium sulfate is whisker by SEM,EDS and so on.

Influence of pH Value and Dispersant on the β-calcium Phosphate Powders Prepared by Precipitation Method

ZHAO Na-ru;KANG Hai-feng;LIU Meng-jiao;SUN Yuan-long;Li Pei-wei

2010, 29(1):  49-52. 

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Calcium phosphate was synthesized by precipitation methods with (NH_4)_2HPO_4 and Ca(NO_3)_2·4H_2O , Polyethylene glycol(PEG) was used as dispersant. The β-TCP powders was obtained after calcined at 850 ℃. The heat-treated powders were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and particle size analysis. The influence of pH value and the molecular weight of PEG on the phase composition, agglomeration were investigated. It was found that the β-tricalcium phosphate powders with high purity, fine crystalline and steady dispersivity could be synthesized when the pH value is 7-8 and the molecular weight of PEG is 6000.

Structure of (NH_4)_2[B_(10)O_(14)(OH)_4]·H_2O Based on Scale Chemistry and Discussion of Synthesis Mechanism

OUYANG Ping;LI Da-guang;PAN Chun-yang;CAI Wei-xian

2010, 29(1):  53-57. 

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Under hydrothermal conditions,A hydrated ammonium hydroxy-borate was synthesized based on "Scale Chemistry". Isolated borate anions self-assemble via polymerization to form one dimensional infinite chain, which are linked by hydrogen bonds to form borate sheets. Ammonium ions and water molecules between these sheets connect adjacent sheets via hydrogen bonds. The compound has been characterized by infrared spectroscopy, elemental analysis, and thermogravimetric analysis as well as single crystal X-ray diffraction studies. The results of single crytal X-ray diffraction analysis are in agreement with the results of hypothesis. The compound exhibits an one-dimensional infinite chain that is formed via polymerization of pentaborate anions, with the guest ammonium ions and water molecules residing in the framework. The compound crystallizes in the triclinic system with space group P-1,a=0.76413(15) nm, b=0.92529(19) nm,c=1.1949(2) nm,α=99.49(3)°,β=105.87(3)°and γ=91.57(3)°

Preparation of Fe-Ce-codoping/Active Bleaching Clay Composite Photocatalyst and Its Photocatalytic Property in Factory Wastewater

WANG Dan-jun;GUO Li;LI Dong-sheng;FU Feng;ZHANG Li-ping;GAO Li-feng

2010, 29(1):  58-65. 

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Fe-Ce codoping nano-TiO_2 catalyst was synthesized by microwave-assisted sol process.XRD,XPS and UV-vis absorption spectroscopy techniques were applied to investigate spectrum properties of Fe-Ce codoping TiO_2 nanoparticles. All of the as-synthesized samples were indicated to be pure anatase phase nano-TiO_2 under XRD measurement and its' diffraction peak broadened obviously after Fe and Ce doping. Results of XPS analysis revealed that many oxygen vacancies were produced in the surface of TiO_2 nanoparticles after Fe and Ce codoping. UV-vis absorption spectra demonstrated that the as-synthesized samples had strong and wide absorption band between 200 to 400 nm and the absorption intensity increased after Fe and Ce doping.Photocatalytic experiment results showed that titanium dioxide's photocatalytic activity increased obviously after Fe and Ce codoping.When the doping amount of Fe and Ce was 0.2% and 0.04% respectively, the as-synthesized sample exhibited high photocatalytic activity- COD removal of cigarette factory wastewater was 89.8% and composite catalyst could be easily recovered for circulation use.

Mechanochemical Effects Brought from Superfine Grinding Tourmaline

LI Wen-wen;WU Rui-hua;LIU Zhen

2010, 29(1):  66-71. 

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Mechanochemical effects brought from superfine grinding tourmaline were researched by XRD, FTIR, DTA-TC and carried through contrast tests of the pre and post grinding particle. The crystal lattice has inflation, but it is the lattice distortion category. Ultrafine grinding causes some vibration and fine structure vanishing.The peak present the characteristic which degenerate and wide, the band which [SiO_4] causes vanishes and red shift. The mechanical energy transforms to internal energy of tourmaline, which causes heat absorption effect maximum value temperature to have reduces (1004 ℃ reduces by the original 907 ℃).Indicated to the smallest particle size tourmaline magnetism nature's research, tourmaline coercive force increases .The crystal lattice periodic destruction, enhances the crystal lattice polarity vibration non-simple harmonics effect and improves the tourmaline in certain wavelength range infrared emissivity effectively. Ultrafine powder of tourmaline produces the anoin increases to a certain extent. When the particle size slightly increases to certain extent, the anoin amount reduces.

Preparation and Characterization of Silver Deposited Nano-TiO_2 through the Chitosan Template Method

SI You-lin;ZHANG Sheng-yi;MIN Hong-lin

2010, 29(1):  72-76. 

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In the presence of the chitosan template, reduction with silver deposited TiO_2 nanoparticles were prepared via reduction with NaBH_4. The Ag/TiO_2 nanoparticles were characterized by TEM, XRD, FT-IR, and UV-Vis. The results showed that chitosan accession to the silver reduction reaction can be controlled easily;Nano-Ag/TiO_2 shaped in the square for most particles and the red-shift was observed clearly in the UV-Vis adsorption spectrum. The photocatalytic activity of the as-prepared Ag/TiO_2 nanopowders is satisfactory, which was confirmed by organic photodegradating tests under the sun light. In the absence of sunlight, the as-prepared Ag/TiO_2 has good anti-bacterial effect.

Study of Numerical Simulation of Oxygen-enriched Combustion Chamber of Cell Glass Furnace

HAN Tao;LIU Zong-ming;LI Xian-song;ZHAO Wei-lin;ZHANG Tie-zhu

2010, 29(1):  77-82. 

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This paper establishes a three-dimensional mathematical model of cell glass furnace in the oxygen-enriched combustion space, which consisting of gas flow model composed of mass conservation equation, momentum conservation equation, energy conservation equation as well as the standard k-ε model; chemical reaction model composed of eddy-dissipation model; and radiation model composed of discrete ordinates model. Based on the object of an annual output of 20000 t fiber glass furnace, the distribution of gas flow and temperature field, velocity field of the furnace are researched by using FLUENT software. According to the comparison between the simulation results and the measured results obtained on the spot, it can be suggested that the mathematical model can objectively reflect the real distribution of the temperature field and velocity field of the cell glass furnace. On the basis of research results, the author makes some recommendations to improve simulation results of the combustion process, that is, to adjust the layout of the spray gun on the combustion space. It also can be shown that the three-dimensional mathematical model plays an important role in the research and application of the oxygen-enriched combustion of cell glass furnace.

FEM Analysis on the Temperature Field of CVD Diamond Film Laser Drilling

WU Xiao-jun;ZUO Dun-wen;XU Feng;WANG Min;HE Jia-yuan;YUAN Jia-jing

2010, 29(1):  83-88. 

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Chemical vapor deposited (CVD) diamond film has bright application foreground in many high-tech fields for its a series of outstanding properties. The temperature field distribution of CVD diamond film laser drilling process is different from other materials because of its diamond graphitization taking place during the process. As a result, studies on thermal field distribution have great importance on both the investigation of the processing mechanism and the optimization of drilling parameters. In this paper, a thermodynamics model considering graphitization of CVD diamond is built at first. Based on the model, FEM simulation research is conducted on laser drilling CVD diamond film. Through simulation the temperature field distribution and the degree of diamond graphitization are presented. Besides, the relation between laser drilling results (average removal rate per pulse and graphitization depth) and laser drilling parameters (laser energy, pulse width, repetition rate) is investigated. It is found that average removal rate per pulse and graphitization depth increases with the increase of laser energy, pulse width, repetition rate, with the laser energy as a key factor. Simulation results show that when choosing the drilling parameters with laser energy 0.5～1.6 J, the pulse width 300～800 ns, repetition rate 30～60 Hz, we could obtain high efficiency together with small heat-affected zone.

Study on Modification and Mechanical Property of Titanium Gypsum

SUI Su;GAO Zi-dong;LI Guo-zhong

2010, 29(1):  89-93. 

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Physical modification methods were used by processes, such as breaking, drying, milling, calcining and ageing. The effect of calcining heat on mechanical properties of titanium gypsum was studied. Sodium sulfate, calces and Portland cement were added to titanium gypsum for the chemical modification. The optimum mix of dosage of additives was obtained. The mechanism of the physical modification and chemical modification was discussed. The experiment showed that the mechanical properties of titanium gypsum samples were improved with 0.5% sodium sulfate, 3% calces and 5% Portland cement added after being calcined at 180 ℃ for 3 h. The mechanical properties of titanium gypsum samples: 2 h flexural strength was 2.6 MPa, 2 h compressive strength was 3.2 MPa, absolutely dry flexural strength was 4.58 MPa and absolutely dry compressive strength was 5.2 MPa. After modification, the strength indices of titanium gypsum samples were better than those of 1.6 Level in the national standard calcined gypsum.

Synthesis of Submicron-sized YAG:Ce,Gd Yellow Phosphor by Malonic Acid Sol-gel Method

SUN Hai-ying;ZHANG Xi-yan;WANG Neng-li;MI Xiao-yun;LIU Quan-sheng

2010, 29(1):  94-97. 

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YAG:Ce,Gd yellow phosphors were synthesized by malonic acid Sol-gel method. The decomposition process of the dry gel and the formation process of crystalline YAG were characterized by TG/DSC and XRD techniques. The influence of Gd~(3+) doping on the luminescent intensity of the phosphor and the microstructure of powders were studied by fluorescence spectrum and SEM. The results indicate that powders calcined at 1200 ℃ for 3 h are about 0.3-1 μm in size with ball morphology. The emission spectrum of phosphor showes gradually red-shift from 525 nm to 550 nm with the increase of doping concentration of Gd~(3+) ion.

Study on the Structure and the SAW Properties of SNGS Piezoelectric Crystal

YANG Hong-wang;LU Gui-wu;LIN Ding-yi;FENG Chao;HUANG Wen-qi;YANG Hong

2010, 29(1):  98-101. 

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The crystal structure, energy band and density of states of Sr_3NbGa_3Si_2O_(14) (SNGS) single crystal was studied, and the phase velocity and electro-mechanical coupling factor of SNGS are calculated for its different cuts. We gained the cut types with good acoustic surface wave (SAW) characteristics, which provides theoretical basis for the SAW application of SNGS piezoelectric crystal.

Study on Manufacture of Anhydrite from Phosphogypsum

XU Lin-qing;ZHOU Fu-tao;SHI Zong-li

2010, 29(1):  102-106. 

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Phosphogypsum is a powder with high CaSO_4·2H_2O content, The P_2O_5 and F impurities present in phosphogypsum can not be removed completely by washing and chemical treatments. When heated at high temperature, phosphogypsum produced an anhydrite and the impurities became inert and harmless. The effects of different activators on setting and hardening of anhydrite cement was studied. The correlation between hydration and chemically combined water was established. The micro formation mechanism of anhydrite cement was examined by SEM and XRD.

Preparation of Mn-doped Barium Titanate Nano-powder by Microwave-hydrothermal Method

MA Mai-xia;ZHANG Guang-xia

2010, 29(1):  107-111. 

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The Mn-doped barium titanate nano-powders were synthesized by Microwave-hydrothermal Method, in which Ti(OC_4H_9)_4 、Ba(NO_3)_2 and C_4H_6MnO_4·4H_2O compounds were used as raw materials. The Mn-doped Barium Titanate nano-powders were characterized by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The primary effects of processing parameters on the growth and morphology of the Mn-doped Barium Titanate were studied. The experimental results showed that the Mn-doped Barium Titanate of pure phase and uniform size was obtained when the concentration of Mn, the reaction time and drying temperature were 1.0%, 30 min and 82 ℃, respectively. And the size of the Mn-doped Barium Titanate powders was about 100 nm.

Preparation of Ceramic Tiles Using Electrolytic Manganese Residue

HU Chun-yan;YU Hong-bing

2010, 29(1):  112-115. 

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In order to reduce the pollution of electrolytic manganese residue and the toxicity of the heavy metal manganese, the preparation of ceramic tiles was studied by using electrolytic manganese residue as the main raw material. The basic formulas were obtained in terms of the CaO-Al_2O_3-SiO_2 ternary system phase diagram, and then they were optimized through the orthogonal design. In the optimal formula, the mass fraction of electrolytic manganese residue reached 40%. The samples with augite and johannsenite as their main crystal phases, whose water absorption was 1.86%, were produced through the lower-temperature and quick-sintering technology: the temperature was 1079 ℃, and the sintering time was 30 minutes. The samples' main technical performance complied with the BⅠb standard of GB/T 4100-2006 'Ceramic tiles'. Experimental results showed that the heavy metal manganese was in the johannsenite's crystal lattice and became a component of the johannsenite's crystal structure. Therefore, less toxicity of manganese will be released into the environment.

Effect of Annealing and Aging Atmosphere on the Properties of SiO_2 Thin Film on CAB Glass

ZHAO Hua;JIN Yang-li;ZU Cheng-kui;HAN Bin

2010, 29(1):  116-120. 

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The SiO_2 thin film deposited on CAB glass substrate by the means of physical vacuum deposition technology was annealed 600 ℃, then the SiO_2 thin film's mechanical property, optical quality and facial morphology were investigated after 20 d aging time under different atmospheres. The results are followed: annealing and aging atmosphere have effects on the properties of SiO_2 thin film's configuration changed, but all the thin films' fraction coefficient is lower than CAB glass substrate, the annealed thin films' hardness is higher than the un-annealed thin films'; The thin film effectively anti-reflect in the visible range, after the annealed treatment, IR transmission is improved. The results showed the SiO_2 thin film can effectively protect the CAB glass from scratch, on the basis of increasing transmission in the range of visible light.

Influence of Off-stoichiometry on Microstructures of Mg_((1-3χ))Al_((2-2χ))O_4 Transparent Spinel Ceramics

HUANG Cun-bing;WEI Chun-lan;LU Tie-cheng

2010, 29(1):  121-125. 

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A series of transparent spinel ceramics were prepared by a two-step sintering process, vacuum sintering followed by hot isostatic pressing. Phase analysis of the powders and the ceramics were performed by X-ray Diffraction (XRD). The calcined Mg_((1-3χ))Al_((2-2χ))O_4 powders with 0≤χ≤0.20 are mono-phased spinel structure. SEM images show that corundum grains deposited on the main grain boundaries, which are beneficial for toughening the ceramics. Taking consideration of transparency and toughening effect of corundum, the microstructure of the ceramic prepared using Mg_((1-3χ))Al_((2-2χ))O_4 powder with χ of 0.14 is expected better for toughening and strengthening ceramic at less expense of transmittance.

Research Progress of Cement Grinding Dynamic Equation

QIAN Hai-yan;ZHANG Bo-lin

2010, 29(1):  126-132. 

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Power consumption has become the major parameter to estimate whether the technology of grinding process is high efficient in cement production. It is widely accepted that under the field of centrifugal force, the grinding system can effectively decrease power consumption compared with the other systems. It is promising for popularization. The paper reviewed the progress of the ball mill and planetary mill grinding process dynamic equation and pointed out the necessity of the study on it.

Preparation and Research Progress of LiFePO_4 Cathode Material

ZHOU Wen-cai;LI Jin-hong;JIANG Xiao-qian

2010, 29(1):  133-137. 

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Olivine structure LiFePO_4 as a promising cathode material attracted much attention because of its advantage, such as rich source of cheap raw materials, non-toxic, high theoretical capacity, thermal stability and good cycling performance. Therefore LiFePO_4 is the preferred material of the next generation of lithium-ion battery. Here olivine-type structure and electrochemical performance of LiFePO_4 are presented briefly, while the preparation and modification aimed at the low electronic conductivity are described in detail.

Study Progress in the Nonlinear Constitutive Behavior of Ferroelectric Ceramics

ZHANG Hui-hui;LIU Feng

2010, 29(1):  138-141. 

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Due to the large coupling between their electrical and mechanical properties, as an important functional material, ferroelectric ceramics has been used successfully in many fields. The nonlinear constitutive behavior of ferroelectric ceramics is one of the important frontiers and hotspots in recent research of solid mechanical and material science. Typical characteristics of the nonlinear constitutive behavior of ferroelectric ceramics and its microphysical mechanism were introduced in this paper firstly. Then the experimental progress in the nonlinear constitutive behavior of ferroelectric ceramics is reviewed in detail. In addition new development trends of nonlinear constitutive experiment of ferroelectric ceramics were introduced.

Effect of Temperature on the X-ray Diffraction Characteristics of Bi_(0.5)Na_(0.5)TiO_3 Powders by Sol-gel Method

WANG Hai-zhen;WANG Xiu-feng;YU Cheng-long;JIANG Hong-tao;SHI Jiang-tao

2010, 29(1):  142-146. 

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Bismuth sodium titanate [Bi_(0.5)Na_(0.5)TiO_3, BNT] is considered to be an excellent candidate for a key material of lead-free piezoelectric ceramics. The clear and transparent gels of BNT can be prepared using tetrabutyl titanate, bismuth nitrate pentahydrate and sodium acetate anhydrous as starting materials by Sol-gel method, the BNT fine powders are produced after the dry gels are calcined. XRD patterns show that the second phase in BNT powders is Bi_(12)TiO_(20). With the temperature increasing, the intensity of the Bi_(12)TiO_(20) reduces and the grain size of BNT powders increases. Well-ordered atoms on (101) crystal plane of the powders are formed by characterization of XRD results.

Study on the Corrosion Resistance of Polymer-modified Reactive Powder Concrete

YUAN Yu-fei;LIN Dong;XI Xiao-lin;YIN Su-hong;WEN Zi-yun

2010, 29(1):  147-152. 

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Using small amount of polymer and ordinary processing condition to modify reactive powder concrete (RPC),the modified and unmodified RPC have been compared for their corrosion resistance with the tests of water-dip-in, acid-dip-in and sulphate solution-dip-in and verified by the ruptural and compressive strength loss rate. The results showed that although the strength of RPC is so high, its the water-resistant is not better than OPC mortar; but after polymer modification, the water resistance of RPC could significantly improve. In the anti-acid corrosion aspect, RPC and the polymer modification RPC are all much better than OPC mortar,while the polymer modified RPC is even better than RPC and its strength loss rate is only about 8% when dipped in hydrochloric acid for 90 d. When soaked in 10% Na_2SO_4 solution, the flexural strength of RPC and polymer modified-RPC both appear first increase and then decrease, but polymer modified-RPC has a better sulfate corrosion-resistance. To explain the materials erosion mechanism, the microstructure of materials has been studied with SEM and EDS analysis.

FEM Analysis on Erosion of Corundum-based Refractory in Refining Ladle

HUANG Ao;GU Hua-zhi;LEI Ming;ZHANG Mei-jie;ZHANG Li;ZHOU Shuang-lin

2010, 29(1):  153-157. 

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According to the application parameter of corundum-based refractory in refining ladle, the Johnson-cook model was chosen, erosion model for refractory in high temperature was established, erosion process of refractory in refining ladle was studied by FEM method. The effects of erosion degree, particle velocity, particle size, porosity on erosion rate of refractory in refining ladle were analyzed. The flow field of bottom blowing ladle with thermal transmission of solid and liquid coupled was considered, the erosion condition of refractory in refining ladle was discussed. The results show that: The Johnson-Cook model, which was applied to simulate ductility cutting erosion of refractory in high temperature, is appropriate and reasonable. The erosion rate with small angle degree from 15-30 is much higher, the erosion rate was decreased following the increasing of angle degree above 25. The relationship between erosion rate and particle velocity, particle size and porosity is exponential. The erosion of refractory in refining ladle is small-angle erosion, particularly in parts of ladle, the slag line near porous plug, the side wall near bottom and porous plug, and etc. performance significantly. The erosion of refractory can be weakened as the interfacial film with higher melting point and density formates.

Study on the Layered Rock Configuration MgO Powder Made by Molten Salt Synthesis

CHEN Hao;WANG Xi-tang;HU Qing-hua

2010, 29(1):  158-161. 

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Layered rock configuration MgO powders were prepared through molten salt synthesis with MgCl_2·6H_2O, CaCO_3 ,LiCl as raw materials.They were studied by using XRD and TEM while reactants were investigated by TG-DSC and XRD.The results indicated that MgO was formed at 430 ℃ calcined for 3 h.When calcined at 600 ℃, only MgO product existed in the resultant after washed by Ethanol. If raw materials calcined at 650 ℃ for 3 h,Mg(OH)_2 powders soaked by water were non-regular flakes.They changed into non-regular granular shapes when decomposed to MgO with 0.1-0.6 μm in diameter. On the other side, Mg(OH)_2 powders soaked by PEG-EDTA solution were tetrahedrons.They changed into layered rock configurations with vertex defected when decomposed to MgO,which brim were up to 1.5 μm in length.Linked by some granular,MgO were non-smooth surface.

Research on Low-temperature Sintering and Properties of Ca_(0.3)(Li_(0.5)Sm_(0.5))_(0.7)TiO_3 Microwave Dielectric Ceramics with Composite Sintering Additive

ZHANG Bin;LI Yue-ming;ZHANG Hua;LIAO Run-hua

2010, 29(1):  162-166. 

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The low temperature sintering process and the microwave dielectric properties of a microwave dielectric material based on Ca_(0.3)(Li_(0.5)Sm_(0.5))_(0.7)TiO_3(CLST-0.7) ceramic with 10 wt % CaO-B_2O_3-SiO_2 (CBS) multiplicity oxide and 4 wt % Li_2O-B_2O_3-SiO_2-CaO-Al_2O_3 (LBSCA) glass and 0-2 wt% CuO multiplicity additives were investigated. The results indicate that with the increasing of CuO content, the bulk density, the dielectric constant ε_r, the product of quality factor and resonance frequency Qf value of CLST-0.7 ceramics all increase first and then decrease and the temperature coefficient of resonant frequency τ_f of CLST ceramics decrease. The sample of CLST with 10 wt% CBS, 4.0 wt% LBSCA and 1.0 wt% CuO sintered at 900 ℃ for 5 h exhibits excellent microwave dielectric properties:ε_r＝67.31,Qf＝2197 GHz,τ_f＝40.28 ppm/℃.

Fabrication and Microstructure Analysis of β-SiAlON Whiskers from Coal Gangue by Carbonthermal Reduction-nitridation

PENG Ben;YUE Chang-sheng;LU Xuan;GUO Min;ZHANG Mei

2010, 29(1):  167-170. 

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β-SiAlON with a lot of slender cylindrical whiskers, has been synthesized by carbonthermal reduction-nitridation method form Coal gangue and carbon black at 1800 K. FESEM photographs showed that diameter of β-SiAlON whisker is 120-220 nm and length in the majority is about 1.5-5 μm. The VLS (vapor-liquid-solid) and VS (vapor-solid) mechanisms have been adopted to explain the behavior of whiskers growth.

Effect of Temperature on Up-converted Fluorescence of Er~(3+)/Yb~(3+) Co-doped Fluoro-oxide Powder

ZHANG Xiang-hua;LONG Yong-tao;ZHOU Xi-feng;LIU Zheng-wei

2010, 29(1):  171-175. 

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Series of Er~(3+)/Yb~(3+) co-doped fluoro-oxide powder samples with the same composition were prepared at different sintering temperatures. One red up-converted emission band centered at 658 nm and two green up-converted emission bands centered at 539 nm,523 nm were observed under the excitation of an 980 nm semiconductor laser, which corresponded to Er~(3+) ions transitions of ~4F_(9/2)→~4I_(15/2) and ~4S_(3/2),~2H_(11/2)→~4I_(15/2), respectively. And the intensity of red emission is stronger than the green ones. It is concluded by comparing each spectra that, the shape of spectra is similar, but the intisity of emission band is obviously different from each other. The sample sintering at 800 ℃ emits the most intensive luminescence. The ratio of the intensity of red emission(658 nm) to green emission(539 nm) increases monotonously with sintering temperature changing from 600 ℃ to 1100 ℃. XRD data show that the oxidation degree of ZnF_2 has been enhanced by increasing sintering temperature, which changed the microstructure of samples. And then the microstructure influenced up-converted fluorescence properties. The relationship between upconversion intensity and pump power of samples were weasured, and the concerned upconversion processes were discussed in this paper.

Effects of R_2O_3(R=Al,B) on Microstructure and Thermal Expansion Behavior of Phosphorus-containing Silicate Opal Glasses

GAO Bin;LIU Shu-jiang

2010, 29(1):  176-179. 

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Phosphorus-containing silicate opal glasses were prepared by means of conventional melt quenching technology, and opaque mechanism and microstructure of the glasses were investigated by XRD,SEM and EDS methods.The influence of R_2O_3(R=Al or B) content on the microstructure and the thermal expansion coefficient was investigated. The results show that heavy opaque glasses are obtained due to the addition of P_2O_5, and this is results from unstable disassemble phase separation; with substituting 3wt%B_2O_3 for Al_2O_3, traces of unknown crystals are precipitated and particles size becomes inhomogenous, and thermal expansion coefficient increases greatly.

Synthesis of Nd:Y_2O_3 Laser Ceramic Nano-powders by Sol-gel Combustion Method

SUN Jing;LI Chang-li;YU Wen-sheng;GENG Ai-fang;LU Qing;LIU Jing-he

2010, 29(1):  180-183. 

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The Nd:Y_2O_3 laser ceramic precusor was prepared by sol-gel combustion method, and Y_2O_3 and Nd_2O_3 were used as raw materials.XRD analysis showed that the optimum calcined temperature of precursor was 1000 ℃. At the same time crystallization was completed.The analysis of DTA-TG indicated that the citric acid was decomposed at 447 ℃,and the temperature of crystal inversion was 590 ℃.The strongest fluorescence peak of Nd:Y_2O_3 laser ceramics precursor was 9421.646 cm~(-1), that was Nd~(3+4)F_(3/2)-~4I_(11/2).

Stab-resistant Characteristics of Kevlar Woven Fabrics Impregnated with Monodisperse Concentrated Suspension

LIU Jun;XIONG Dang-sheng

2010, 29(1):  184-187. 

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Monodisperse concentrated suspensions of different concentrationon were prepared with St(O)ber method and centrifugation/solvent exchange procedure. The rheology behavior and the stab resistance of Kevlar fabrics impregnated with each concentration were studied. The results show that when the mass percent of prepared suspension is lower than 50%, suspension shows weak shear thickening behavior, which viscosity increases and critical shear rate reduces with increasing concentration; when it is about 55%, suspension shows shear thickening at first and then transfer to shear thining; when it is bigger than 65%, shear thinning comes first and then appears obviously shear thickening stab resistance of impregnated Kevlar fabrics improves at some extent, which is 1.66 times than that of pure Kevlar.

Properties and Sintering Behavior of Ceramics Used Fly Ash and Red Mud as Raw Materials

LIU Xue-yin;JIANG Bin;HUANG Zhao-hui;LIU Yan-gai;FANG Ming-hao

2010, 29(1):  188-192. 

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The effects of temperature on the phase characteristics and sintering properties of fly ash and red mud between 1050 ℃ to 1200 ℃ had been studied. The results showed that the main mineral phase of fly ash was quartz (SiO_2) and mullite(3Al_2O_3·2SiO_2), the major mineral phases of red mud were gehlenite (Ca_2Al_2SiO_7), quartz (SiO_2), andradite(Ca_3Fe_2+3(SiO_4)_3) and morimotoite (Ca_3TiFeSi_3O_(12)). Different ratio of fly ash and red mud samples got the relatively lower porosity, the higher bulk density and compressive strength at 1200 ℃. The 5# sample sintered at 1200 ℃ got the porosity of 1.67%, bulk density of 2.10 g·cm~(-3), compressive strength of 123.23 MPa, achieving sintering dense state, and the dominant phase was (anorthite,sodian) and mullite. The formation of mullite and addition of glass phase in the samples contributed to dense sintering at high temperature.

Mix Proportion Design of RPC Based on Orthogonal Theory

ZHAO Qing-xin;LIU Zhao-yang;HAO Sheng-wang

2010, 29(1):  193-197. 

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A new method for preparing reactive powder concrete (RPC) was proposed based on the orthogonal theory and current preparing experience experiments. The method contains two steps, first the best matrix of PRC material should be selected by the orthogonal design theory, then the dosage of steel fiber is optimized through experiments. On basis of the method, RPC material was prepared with cement P.O 42.5R, fly ash, silica fume, river sand, super-plasticizer and steel fiber, and its flexural strength can reach 38.6 MPa.

Effect of Boron and Fluorine Co-doping on the Band Gap Structure of TiO_2 and Its Visible Light Photocatalytic Performance

CAO Guang-xiu;LI Yao-gang;ZHANG Qing-hong;WANG Hong-zhi

2010, 29(1):  198-203. 

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Boron and fluorine codoped TiO_2 powders were prepared by hydrolysis of titanium tetra-n-butyl oxide in a mixed NH_4F-H_3BO_3-H_2O solution. The XRD results showed that the co-doping of boron and fluorine could not only efficiently inhibit the grain growth but also suppress the phase transition of anatase to rutile. When the molar ratios of B and F to Ti are 20∶ 100 and 5∶ 100 and calcined at 600 ℃, UV-vis spectroscopy of the sample showed better visible light responding. XPS results revealed that the Ti-B bonds and Ti-F bonds have formed which could extend the absorption spectra to visible light region and enhance visible light photocatalytic activity. When the molar ratios of B and F to Ti are 20∶ 100 and 5∶ 100 and calcined at 600 ℃, the degradation rate of 4-chlorophenol (4-CP) over the sample was about 1.5 to 3.0 times higher than that for other doped samples and undoped TiO_2. The total organic carbon (TOC) removal rates of 4-CP showed that 4-CP has been mineralized efficiently with the sample under visible light illumination.

Preparation and Thermal Conductivity Measurement of Al_2O_3-water Nanofluid in Low Volume Concentration

LI Jin-kai;ZHAO Wei-lin;LIU Zong-ming;HAN Ya-dong

2010, 29(1):  204-208. 

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Al_2O_3-water nanofluid with 40 nm particle size was produced with various volume concentrations from 0.1% to 0.5% using a two-step method with ultrasonication and without any surfactant. The analysis of zeta potential, particle size and absorbancy indicates that 3 hours of ultrasonic vibration can uniformly disperse the Al_2O_3 nanoparticles in water. In this experimental process, thermal conductivities were mearsured.The results show that the thermal conductivities of Al_2O_3-water nanafluids are all higher than water. The enhancement of thermal conductivity is 5.40%-17.9% in the low volume concentration range of 0.1%-0.5%. Enhancement of thermal conductivity is 7.23%-23% in the temperature range of 17-57 ℃ at a volume fraction of 0.2%. Furthermore, the experimental results show the thermal conductivities of Al_2O_3-water nanofluids increased nonlinearly with the nanoparticle volume concentration and temperature increasing.

Study on Alumina-zirconia Composite Powder Prepared by Chemical Methods

TIAN Xiao-li;XUE Qun-hu;XUE Chong-bo

2010, 29(1):  209-213. 

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Alumina-zirconia composite powders were prepared by two chemical methods, which were Sol-gel method and co-precipitation method, and then characterized by some equipments: size of the granularity was expressed by laser particle size analyzer, phase composition was analyzed by X-ray diffraction (XRD) and distribution of alumina and zirconia at microscopic view was observed by scanning electron microscope (SEM). The experimental results show that compared with co-precipitation method, the powder from Sol-gel method was preferable, of which the granularity was much thinner, the content of tetragonal zirconia was much higher and the distribution of alumina and zirconia was much evener.

Effect of Annealing Temperature on Microstructure and Surface Topography of In-doped ZnO Thin Films

DAI Jie-lin

2010, 29(1):  214-218. 

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Microstructure, surface morphology and optical properties of ZnO thin film with 4at.% In doping concentration were measured by X-ray diffractometer, scanning electron microscope and UV-Vis spectrophotometer. Microstructure analysis shows that all films are polycrystalline and exhibit the hexagonal wurtzite structure. The crystallinity is deteriorated due to doping with indium. Intensity of the diffraction peaks almost has no change with annealing temperature increases. Surface morphology results indicate that the films are irregular, and possess the particle size of 50-100 nm having uniform and dense microstructure. Optical transmittance spectra show that as annealing temperature increases, the value of optical bandgap decreases from 3.267 to 3.197 eV, which might be induced by the transition of residual stress.

Process Research of Mg-Al-CO_3 LDHs Nanopowders Using a Two-stage Reactor

LIU Yue-jun;QUE Yong-sheng;YANG Jun;LIU Yiwu;YANG Shuang-lei

2010, 29(1):  219-223. 

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The nanopowders of magnesium aluminium layered double hydroxides (Mg-Al-CO_3 LDHs) were prepared from the reaction of the salt solution of MgCl_2·6H_2O, AlCl_3·6H_2O and precipitating agent of Na_2CO_3, NaOH in a two-stage reactor with up and down reaction chamber. The effects of reactant concentration, stirring speed, surfactant type on the crystal structure, particle size, and size distributionthe have been studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), laser particle size distribution analyzer. The results demonstrated that the product synthesized in the optimum conditions has excellent uniform and plate structure with a particle size of approximately 30-50 nm, and has higher degrees of crystallinity. As the reactant concentration increasing, particle size became smaller and more uniform; stirring speed increasing, particle size decreased and particle size distribution curve became narrower. The reasult also indicated that different types of surfactants have a significant influence on the crystal structure.

Study on the Test Method of the Anti-carbonation Properties of Common Portland Cement

JI Xi-xian;PAN Gang-hua;YANG Ling;LI Li

2010, 29(1):  224-229. 

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The anti-carbonation property of cement is one of the main factors which affect the anti-carbonation property of the concrete. It is necessary to control the anti-carbonation property of cement in order to ensure the carbonation property of concrete. Therefore, it needs to study the characterization and testing methods of the anti-carbonation property of cement. In this paper, a testing method was designed in order to study the characterization and testing methods of the anti-carbonation property of cement, which could clearly distinguish the differences between the anti-carbonation properties of various cements.

Research on Mechanism of Bonding and Plug Caused by Coal Combustion

LI Jian-xi;YU Su;SHU Yi-zhou;TANG Shuang-lu;LU Kai-fang;ZHANG Ping;CAO Ying-ying

2010, 29(1):  230-234. 

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One of the important reasons is the incomplete combustion of coal in new dry cement kiln system. In this paper, its mechanism was studied and discussed.It shows that the incomplete combustion of coal can decrease the temperature of the transient liquid phase on the system, increase the evaporation rate and the sulfur cycle and generate high local temperature so as to promote the crust bonding and plug effect.

Research on the Grinding Dynamics of Cement Clinker

WU Chun-fen;FANG Ying;LI Zhen;GE Peng-peng

2010, 29(1):  235-238. 

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The cement clinker was milled for different time in the planetary ball mill. Investigations were carried out with the particle size distribution, the blaine surface as well as 45 μm sieve residue of the clinker. With the Rosin-Rammler-Bennet equation as the particle size distribution model, the grinding dynamic feature of cement clinker was studied and evaluated in the experiment. By the methods of linear regression analysis and the characteristic diameter analysis of grinding dynamic feature. The experimental results show that the specific surface area, the characteristic diameter and the uniformity coefficient of ground clinker powder are in linear relation to logarithmic or double logarithmic of grinding time. The grinding dynamics of cement clinker follows dS/dt=170.66/t, and the fineness of clinker powder shouldn' t be higher than 550 m~2·kg~(-1).

Research on the Properties of Al_2O_3-Si_3N_4-SiC Composite

CHEN Chun-xia;LI Yong;KANG Hua-rong;XIA Wen-bin;YUE Yue-hong

2010, 29(1):  239-242. 

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Taking brown alumina, silicon nitride and carbon silicon as raw materials, the specimens were prepared under oxidization atmosphere. The specimens was embedded in carbon at temperatures of 1500 ℃,1550 ℃ and 1600 ℃ for 5 h respectively. The phase change of the specimens fired under oxidation atmosphere and the stability of Si_3N_4 under carbon-embedded were studied by XRD, SEM and EDS, combining with thermodynamic analysis.The results show that there is a mullite solid solution Si_6Al_(10)O_(21)N_4 created after fired under oxidation atmosphere.Si_3N_4 and Si_6Al_(10)O_(21)N_4 will transform to SiC partly after carbon-embedded, and the transition temperature of Si_3N_4 and Si_6Al_(10)O_(21)N_4 are above 1500 ℃ and 1550 ℃ respectively.

Study on the Hydration Mechanism of Coal Gangue Modified Cement Mortar by Microstructure Characterization

XU Zi-fang;ZHANG Ming-xu;MIN Fan-fei

2010, 29(1):  243-247. 

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The addition of suitable amount of coal gangue to cement mortar may increase cement mortar strength. When the content of coal gangue is 9%, the compressive strengths at 3 and 28 d increased 1.0 MPa and 2.0 MPa, respectively. The analysis by XRD, TGA-DTA and SEM showed that the addition of coal gangue prompted the hydration reaction at early stage of 7 days. The hydration products are AFt, C-S-H, AFm and Ca(OH)_2. These hydration products and crystal structures are different. After modification, hydration products increased and the hydration speed was quickened. As a result, the cement mortar strength increased.

Amorphous Si-C-O-N Coating on SSiC Ceramics for Surface Modification

TANG Hui-dong;SUN Yuan-yuan;LI Long-zhu;TAN Shou-hong

2010, 29(1):  248-252. 

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In order to improve the low reflectance of polished SSiC, the amorphous Si-C-O-N coating was coated on the surface of SSiC ceramics by RF magnetron sputtering. The as-prepared coating was characterized by XRD, FTIR and XPS, et al. The reflectance was also determined in the visible range. The results show that the coating was composed of Si-N, Si-C and Si-O bondings. The surface defects decrease obviously after polished. The surface roughness yields to angstrom grade. The lowest reflectance in visible range increases to 90%. The scalar scattering theory was used to analyze the cause in increasing the reflectance.

Simulating Experiments of Solidification of Sandy Soil Contaminated with Actinides by SHS Method of Thermite

ZHANG Song-lin;ZHANG Qing-ming;QIN Zhi-gui;TIAN Mei

2010, 29(1):  253-256. 

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Simulating experiments were conducted for solidification of sandy soils contaminated with actinides by SHS method of thermite. The main work consists of analysis of solidification mechanisms, selection of actinides analogs, test of concentration of the actinide analogs in the block of iron and leach rates of the actinide analogs in the solidification form. The results show that the leach rates of Ce and Er in the solidification form are on the order of 10~(-3)-10~(-5) g·m~(-2)·d~(-1) . XRD and SEM indicate that Er and Ce in the solidification form exist in form of silicate crystal surrounded by glass. Concentrations of the actinide analogs in the iron block are extremely low.