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Synthesis of Al_2OC Compound by Carbothermal Reduction Process with boron oxide Additive

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China's Refractories 2014年第4期23卷 41-44页

作者： YANG Luocheng ZHU Hongxi DENG Chengji CUI Peng The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology

The synthesis method of Al2OC by adding B2O3 was studied to modulate the traditional synthesis *** mixtures of active carbon,alumina and boron oxide with different carbon contents were heated at 1 700 ℃ for 2 h in flowing argon atmosphere to get the Al2OC *** results indicate that the addition of B203 promotes the formation of Al2OC,which is dependent on the addition of B2 O3,and the Al2 OC content in the products increases with the increase of *** systematically exploring the ratio of active carbon,alumina and boron oxide,the best formulation and the corresponding reaction mechanism were determined.

关键词： Al2OC carbothermal reduction boron oxide synthesis mechanism

Planar Tricyclic B8O80/- Clusters:boron oxide Analogs of s-Indacene C12H8

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Planar Tricyclic B8O80/- Clusters:Boron Oxide Analogs of s-I...

Preparation, characterization and photocatalytic activities of boron- and cerium-codoped TiO_2

第十三届全国量子化学会议

作者： Da-Zhi Li Lin-Yan Feng Li-Juan Zhang Wen-Juan Tian Qiu-Hong Xu Hua-Jin Zhai Si-Dian Li College of Chemistry and Chemical Engineering Binzhou University Nanocluster Laboratory Institute of Molecular ScienceShanxi University

boron-containing heterocyclic clusters possess unique bonding characteristics. Some skeleton materials with boron-containing heterocycles as building units have potential application in gas adsorption, selective catalysis and optics.[1-2]The s-indacene CH with C symmetry can be described as a limit system between the classes of aromatic and antiaromatic molecules due to its unique structural and magnetic properties.[3] Inspired by the principle of isoelectronic species, we design planar tricyclic BOmolecules with D symmetries. Interestingly, D BO(A) and D BO.(B) are the global minima of the systems based upon global structural searches and B LYP and CCSD(T) calculations. The D structures feature tricyclic system(5+6+5), which consists two BOfive-membered rings fused together via two bridging O atoms and terminated by two BO groups. Bonding analyses show that the closed-shell BO cluster possesses 12 delocalized π electrons, closely analogous to the bonding pattern of the s-indacene CH.

关键词： boron oxide analog polycyclic aromatic hydrocarbons

来源： cnki会议评论

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Journal of Environmental Sciences 2007年第1期19卷 90-96页

作者： WEI Chao-hai TANG Xin-hu LIANG Jie-rong TAN Shu-ying institute of Environmental Science South China University of Technology Guangzhou 510640 China Department of Environrnental Engineering Jinan University Guangzhou 510632 China

boron- and cerium-codoped TiO2 photocatalysts were synthesized using modified sol-gel reaction process and characterized by X- ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, particle size distribution （PSD）, diffuse reflectance spectra （DRS）, and Brunauer-Emmett-Teller （BET）. The photocatalytic activities were evaluated by monitoring the degradation of dye Acid Red B （ARB）. The results showed that the prepared photocatalysts were mixed oxides mainly consisting of titania, ceria, and boron oxide. The structure of TiO2 could be transformed from amorphous to anatase and then to rutile by increasing calcination temperature; the transformation being accompanied by the growth of particle size without any obvious change in phase structure of CeO2. The XPS of B1.6Ce1.0-TiO2 prepared at 500℃ showed that a few boron atoms were incorporated into titania and ceria lattice, whereas others existed as B2O3. Cerium ions existed in two states, Ce^3＋ and Ce^4＋, and the atomic ratio of Ce^3＋/Ce^4＋ was 1.86. When boron and cerium were doped, the UV-Vis adsorption band wavelength showed an obvious shift toward the visible range （〈526 nm）. As the atomic ratio of Ce/Ti increased to 1.0, the absorbance edge wavelength increased to 481 nm. The absorbance edge wavelength decreased for higher cerium doping levels （Ce/Ti=2.0）. The particles size ranged from 122 to 255 nm with a domain at 168 nm （39.4%）. The degradation of ARB dye indicated that the photocatalytic activities of boron- and cerium-codoped TiO2 were much higher than those of P25 （a standard TiO2 powder）. The activities increased as the boron doping increased, whereas decreased when the Ce/Ti atomic ratio was greater than 0.5. The optimum atomic ratio of B/Ti and Ce/Ti was 1.6 and 0.5, respectively.

关键词： titania ceria boron oxide photocatalytic activity Acid Red B

Extracting B_2O_3 from calcined boron mud using molten sodium hydroxide

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Rare Metals 2015年第10期34卷 744-751页

作者： Zhi-Qiang Ning Yu-Chun Zhai Qiu-Shi Song School of Materials and Metallurgy Northeastern University

Extracting B2O3 from calcined boron mud(CBM) was studied. The effect of factors such as reaction temperature and NaO H-to-CBM mass ratio on B2O3 extraction efficiency was investigated. The results show that increasing reaction temperature and NaO H-to-CBM mass ratio increases B2O3 extraction efficiency. There are two stages for the B2O3 extracting process: 0–20 min is the first stage, which is rapid; 20–50 min is the second stage, which is slower than the first stage. The overall extracting process follows the shrinking core model, and the first and second stages are determined to obey the surface chemical reaction model and the diffusion through the products layer model,respectively. The activation energies of the first and second stages are calculated to be 41.74 and 15.43 kJ·mol-1,respectively. The B2O3 extracting kinetics equations of the first and second stages are also obtained.

关键词： boron mud Sodium hydroxide boron oxide Kinetics

Ammonia borane-based reactive mixture for trapping and converting carbon dioxide

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Frontiers of Materials Science 2022年第2期16卷 71-81页

作者： Carlos A.CASTILLA-MARTINEZ Bilge COŞKUNER FİLİZ Eddy PETIT Aysel KANTÜRK FİGEN Umit B.DEMIRCI Institut Europeen des Membranes(IEM) UMR 5635Univ MontpellierENSCMCNRSMontpellierFrance Department of Metallurgy and Materials Engineering Yildiz Technical UniversityİstanbulTurkey Department of Chemical Engineering Yildiz Technical UniversityİstanbulTurkey

Ammonia borane(NH_(3)BH_(3))is a reducing agent,able to trap and convert carbon *** the present work,we used a reactive solid consisting of a mixture of 90 wt.%of NH_(3)BH_(3)and 10 wt.%of palladium chloride,because the mixture reacts in a fast and exothermic way while releasing H2 and generating catalytic *** took advantage of such reactivity to trap and convert CO_(2)(7 bar),knowing besides that Pd0 is a CO_(2)hydrogenation *** operation(*** 1)was effective:BNH polymers,and B−O,C=O,C−O,and C−H bonds(like in BOCH_(3)and BOOCH groups)were *** then(in stage 2)pyrolyzed the as-obtained solid at 1250℃ and washed it with *** doing so,we isolated cyclotriboric acid H_(3)B3O6(stemming from B2O3 formed at 1250℃),hexagonal boron nitride,and graphitic *** conclusion,the stage 1 showed that CO_(2)can be‘trapped’and converted,resulting in the formation of BOCH_(3)and BOOCH groups(possible sources of methanol and formic acid),and the stage 2 showed that CO_(2)transforms into graphitic carbon.

关键词： ammonia borane boron nitride boron oxide carbon dioxide graphitic carbon

Effects of heat treatment on properties of boron nitride fiber

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Science China(Technological Sciences) 2012年第5期55卷 1376-1380页

作者： LI Duan ZHANG ChangRui LI Bin CAO Feng WANG SiQing State Key Laboratory of Advanced Ceramic Fibers&Composites College of Aerospace&Materials EngineeringNational University of Defense TechnologyChangsha 410073China

The boron nitride fibers were heated at the range of 600-1400℃ in flowing nitrogen and air, respectively, and the effects of heat treatment on the structure, composition and morphology of BN fibers were studied. The results showed that BN fibers exhibited smooth surfaces, and that t-BN was the main phase with a little B203 included. After heat treatment at 1400℃ in nitrogen atmosphere, the fibers displayed rough surfaces with little change in mass. Better crystallinity was obtained with the increasing temperature. During heat treatment in air, the fibers were oxidized severely as the temperature went up, especially at 1400℃. The volatilization of B203, HBO2 and H3BO3 led to the pores on the surfaces of the fibers, while the boron oxide glaze and nitrogen gas produced during the oxidation process protected the fibers from further oxidation.

关键词： boron nitride fiber heat treatment oxidation boron oxide surface

Effect of B_2O_3 on Melting Temperature of CaO-Based Ladle Refining Slag

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Journal of Iron and Steel Research International 2010年第10期17卷 18-22页

作者： WANG Hong-ming LI Gui-rong LI Bo ZHANG Xue-jun YAN Yong-qi School of Materials Science and Engineering Jiangsu University Zhenjiang 212013 Jiangsu China Stainless Steel BranCh Baosteel Group Shanghai 200431 China

B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting temperature of two series of refining slags including the low basicity slags （the mass ratio of CaO/SiO2 is 3--4） and the high basicity slags （the mass ratio of CaO/SiO2 is 5--8.75） were investigated. The slag melting temperature was meas- ured using the hemisphere method. The results indicate that the fluxing action of B2O3 is better than that of CaF2 and A1203. For the CaO-based refining slag with low basicity, the melting temperature is decreased effectively when B2O3 is used to substitute for equal mass of CaF2, Al2O3 and SiO2, respectively. For the CaO-based refining slag with high basicity, when CaF2 is substituted by B2 03, the melting temperature can be decreased remarkably. Espe- cially, when the mass ratios of CaO/Al2O3 and CaO/SiO2 are in the range of 1.1--4.0 and 5.25--8. 0, respectively, the slag melting temperature is lower than 1 300 ℃. Therefore, the 132 03-containing refining slags with high ratios of CaO/Al2O3 and CaO/SiO2 have ultra low melting temperature.

关键词： fluoride-free slag boron oxide CaO-based refining slag melting temperature

Tribological behavior of hot-pressed boron carbide with oxidation

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Journal of Central South University of Technology 2001年第2期8卷 89-93页

作者： WANG Ling sen,WU Fang,ZHANG Jin sheng,FAN Yi,LIU Bo wei,GAO You (State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China) State Key Laboratory for Powder Metallurgy Central South University Changsha China

The oxidation behavior at 973 1 273 K and the effect of oxidation on the room temperature tribological properties of hot pressed boron carbide ceramic were investigated. Oxidized samples were studied by X ray diffractometer and scanning electron microscopy. It is demonstrated that the oxidation results in the formation of a thin transparent B 2O 3 film, and the oxide film is severely cracked during cooling due to the thermal expansion mismatch between the oxide film and B 4C substrate. B 2O 3 reacts with moisture in air to form boric acid, which is a kind of solid lubricant. The sliding friction factors of oxidized B 4C pair are about 0.05 0.08, compared to 0.25 0.35 of the as received B 4C pair. When the oxidation temperature is up to 1 273 K, severe unstability and increase of friction factor are observed. Visual inspection of the wear track reveals that the lubricant film is broken and some debris particles occur on and around the rubbing surfaces, because the friction interface is rough by the severe etching of grain boundaries.

关键词： oxidation boron carbide friction factor boron oxide boron acid

Effects of B_2O_3 and CaF_2 on Melting Temperatures of CaO-SiO_2-Fe_2O_3 System Fluxes

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Journal of Iron and Steel Research International 2013年第6期20卷 21-24页

作者： WANG Hong-ming YANG Li-li LI Gui-rong ZHU Xiang ZHU Hua ZHAO Yu-tao School of Materials Science and Engineering Jiangsu University Jiangsu Shasteel Group

Fluorite is widely employed as fluxing agent in metallurgy flux , which inevitably leads to serious fluorine pollution.B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3steelmaking fluxes to substitute for *** effects of B2O3 and CaF2 on the melting properties of this system were *** melting temperatures of fluxes including softening temperature （Ts）, hemispherical temperature （Th）, and flow temperature （Tf） were measured using the hemisphere *** results indicate that the fluxing effect of B2O3is more significant than that of CaF2 .When the addition amount of B2O3 （mass percent） exceeds 6% , the melting temperatures of fluxes including Ts , Th and Tf are decreased lower than 1 300℃.The basicity of fluxes has a significant effect on the melting temperature , and the melting temperatures of the fluxes increase with the increase of fluxes *** , when B2O3 is used as fluxing agent , the melting temperature changes little with the basicity increasing from 2.5 to 5.0. These characteristics are suitable for steelmaking *** , Fe2O3 has an important fluxing effect on this CaO-based steelmaking *** indicates that the fluxes system is suitable for steelmaking process.

关键词： boron oxide calcium fluoride melting temperature CaO-SiO2-Fe2O3 system steelmaking flux