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1.
V. A. Sokolov 《Refractories and Industrial Ceramics》2005,46(5):338-343
The synthesis and comprehensive study of fusion-cast refractories based on the Cr2O3 - MgO - SiO2 system containing more than 60% Cr2O3 are reported. Analyzed by x-ray diffractometry and petrography, the synthesized materials display a phase composition represented
by a complex spinel and escolaite. Tested for stability by molten alkali-free borosilicate E-glass, the synthesized refractories
are shown to be not inferior in corrosion resistance to a chromium oxide-based ceramic refractory.
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Translated from Novye Ogneupory, No. 10, pp. 68 – 74, October, 2005. 相似文献
2.
V. A. Sokolov 《Refractories and Industrial Ceramics》2005,46(3):197-200
The synthesis and properties of fused materials in the ZrO2 - SiO2 - CaO system (83.1 – 91.7% ZrO2, 0.3 – 9.2% SiO2, and 0.6 – 7.8% CaO) are reported. CaO-assisted stabilization of ZrO2 to yield a cubic modification is reached at a SiO2 concentration of ≤ 4.3%. The arc furnace technology developed can be used to fabricate crucibles, tubes, rings (of diameter
320 mm and height 310 mm), and other shaped components from high-zirconia refractory materials with more than 90% ZrO2.
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Translated from Novye Ogneupory, No. 3, pp. 37 – 40, March, 2005. 相似文献
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4.
V. A. Sokolov T. Ya. Malysheva M. D. Gasparyan 《Refractories and Industrial Ceramics》2008,49(2):146-148
Details are given of the synthesis and testing of flux-cast refractory materials in the alumina-rich region of the Al2O3-MgO-B2O3 system; XRD and petrography indicate that the main structure-forming phases are corundum and magnesian spinel. In subordinate
amounts there are the boroaluminate 9Al2O3·2B2O3 and the previously unknown compound 4Al2O3·MgO·2B2O3, whose composition has been established by microprobe analysis. Corrosion tests showed that three-component systems containing
magnesium and boron oxides at levels of 5–10% do not increase the corrosion resistance of refractories in molten sodium-calcium-silicate
glass and electrovacuum borosilicate glass.
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Translated from Novye Ogneupory, No. 3, pp. 161–163, March, 2008. 相似文献
5.
Huimei Yu Xiaoxing Wang Zhu Shu Mamoru Fujii Chunshan Song 《Frontiers of Chemical Science and Engineering》2018,12(1):83-93
A series of Al2O3 and CeO2 modified MgO sorbents was prepared and studied for CO2 sorption at moderate temperatures. The CO2 sorption capacity of MgO was enhanced with the addition of either Al2O3 or CeO2. Over Al2O3-MgO sorbents, the best capacity of 24.6 mg- CO2/g-sorbent was attained at 100 °C, which was 61% higher than that of MgO (15.3 mg-CO2/g-sorbent). The highest capacity of 35.3 mg-CO2/g-sorbent was obtained over the CeO2-MgO sorbents at the optimal temperature of 200 °C. Combining with the characterization results, we conclude that the promotion effect on CO2 sorption with the addition of Al2O3 and CeO2 can be attributed to the increased surface area with reduced MgO crystallite size. Moreover, the addition of CeO2 increased the basicity of MgO phase, resulting in more increase in the CO2 capacity than Al2O3 promoter. Both the Al2O3-MgO and CeO2-MgO sorbents exhibited better cyclic stability than MgO over the course of fifteen CO2 sorption-desorption cycles. Compared to Al2O3, CeO2 is more effective for promoting the CO2 capacity of MgO. To enhance the CO2 capacity of MgO sorbent, increasing the basicity is more effective than the increase in the surface area. 相似文献
6.
B. S. Seplyarskii G. B. Brauer A. G. Tarasov 《Combustion, Explosion, and Shock Waves》2010,46(3):301-306
Results of a combustion study of a powder mixture of Cr2O3 and Al burnt in an argon flow are reported. The combustion process is affected by a pressure difference along the filler by evacuating one end of the reaction cell. Effects of the initial density, gasifiable additive (borax or sodium carbonate), and pressure difference on specific features of the combustion process are examined. The data obtained were interpreted within the convective-conductive combustion theory of heterogeneous condensed systems. 相似文献
7.
S. A. Nemov A. V. Marchenko P. P. Seregin E. A. Tomil’tsev 《Glass Physics and Chemistry》2007,33(6):658-660
Triply and doubly charged states of europium are revealed by 151Eu Mössbauer spectroscopy in the structure of glasses of the composition (mol %) 19.5Al2O3, 31.5SiO2, 26.5MnO, and 22.5Eu2O3. The isomer shifts in the Mössbauer spectra of Eu3+ and Eu2+ ions in the structure of glasses differ from the isomer shifts in the spectra of the Eu2O3 and EuO compounds. This difference is explained by the fact that the electron density at 151Eu nuclei is affected by the manganese and aluminum atoms, which are not bound directly to the europium atoms. The broadening of the spectra of the Eu2+ ions in glasses is caused by the nonuniform isomer shift. 相似文献
8.
Jeong Gil Seo Min Hye Youn Kyung Min Cho Sunyoung Park Sang Hee Lee Joohyung Lee In Kyu Song 《Korean Journal of Chemical Engineering》2008,25(1):41-45
An Al2O3-ZrO2 xerogel (AZ-SG) was prepared by a sol-gel method for use as a support for a nickel catalyst. The Ni/AZ-SG catalyst was then
prepared by an impregnation method, and was applied to hydrogen production by steam reforming of LNG. A nickel catalyst supported
on commercial alumina (A-C) was also prepared (Ni/A-C) for comparison. The hydroxyl-rich surface of the AZ-SG support increased
the dispersion of nickel species on the support during the calcination step. The formation of a surface nickel aluminate-like
phase in the Ni/AZ-SG catalyst greatly enhanced the reducibility of the Ni/AZ-SG catalyst. The ZrO2 in the AZ-SG support increased the adsorption of steam onto the support and the subsequent spillover of steam from the support
to the active nickel sites in the Ni/AZ-SG catalyst. Both the high surface area and the well-developed mesoporosity of the
Ni/AZ-SG catalyst improved the gasification of adsorbed surface hydrocarbons in the reaction. In the steam reforming of LNG,
the Ni/AZ-SG catalyst showed a better catalytic performance than the Ni/A-C catalyst. Moreover, the Ni/AZ-SG catalyst showed
strong resistance toward catalyst deactivation. 相似文献
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10.
A. A. Abramovich O. V. Karban' V. V. Ivanov E. I. Salamatov 《Glass Physics and Chemistry》2005,31(5):709-711
The structures of the single-phase coarse-grain (~1000–3000 nm) corundum ceramic material synthesized by the traditional method and the nanocomposite composed of fine-grain (~300 nm) corundum with iron nanoinclusions and prepared through magnetic pulsed compaction with subsequent sintering are studied using atomic-force microscopy and X-ray powder diffraction. For both ceramic materials, the thermal conductivity is investigated in the temperature range 150–700 K for the purpose of elucidating how the structure affects their thermal and physical properties. 相似文献
11.
Analysis of the formation of Al<Subscript>2</Subscript>O<Subscript>3</Subscript> + Fe nanocomposites
O. Yu. Goncharov O. V. Karban’ O. M. Nemtsova I. A. Il’in 《Glass Physics and Chemistry》2009,35(2):210-218
The formation of Al2O3 + Fe nanocomposites (in the range 0–20 wt % Fe) in the course of three sequential processes, such as dispersion, compaction, and sintering at a temperature of 1573 K, is investigated. It is revealed that the sintering is accompanied by the formation of the spinel phase at interfaces. It is demonstrated that the composition of the sintered samples corresponds to an equilibrium composition at a temperature of approximately 1073 K and that the spinel phase serves as a barrier layer preventing oxidation of iron 相似文献
12.
Synthetic spinels of the system MgO-Cr2O3-Al2O3-Fe2O3 are considered and the desirability of organizing their production for the refractory industry is demonstrated.
Translated from Novye Ogneupory, No. 6, pp. 32–35, June 2008. 相似文献
13.
An investigation on viscosity was conducted 2 weeks after the Al2O3-water nanofluids having dispersants were prepared at the volume concentration of 1-5%. The shear stress was observed with
a non-Newtonian behavior. On further ultrasonic agitation treatment, the nanofluids resumed as a Newtonian fluids. The relative
viscosity increases as the volume concentrations increases. At 5% volume concentration, an increment was about 60% in the
re-ultrasonication nanofluids in comparison with the base fluid. The microstructure analysis indicates that a higher nanoparticle
aggregation had been observed in the nanofluids before re-ultrasonication. 相似文献
14.
I. A. Zvereva V. F. Popova E. A. Tugova N. S. Pylkina V. V. Gusarov 《Glass Physics and Chemistry》2005,31(6):808-811
The phase equilibria are investigated and the phase diagram is constructed for the Gd2O3-SrAl2O4 pseudobinary join of the Gd2O3-SrO-Al2O3 ternary oxide system. One ternary compound, namely, Gd2SrAl2O7, is revealed in the Gd2O3-SrAl2O4 join. It is found that this compound undergoes congruent melting. 相似文献
15.
Kamila Michalska Paweł Kowalik Wiesław Próchniak Tadeusz Borowiecki 《Catalysis Letters》2018,148(3):972-978
16.
Structure and crystalline behavior of the ternary system ZnO-B2O3-P2O5 glasses were investigated by means of X-ray diffraction (XRD) and infrared Raman spectra. The research showed that number
of the planar [BO3] units increases with the increase of B2O3 content. When the B2O3 content is above ≥10 mol %, the relative content of planar [BO3] units increases rapidly and causes weakening of the glass structure and decrease in the chemical stability. In the crystallized
glasses the predominant crystal phase Zn2P2O7 decreases with the increase of B2O3 content, while the crystal phase BPO4 increases with it, which cause the declining of chemical stability and the decrease of thermal coefficients of expansion. 相似文献
17.
Electrodeposition of Zn, Co and ZnCo from acid sulfate solutions onto steel was investigated in this first part of a study
of the effects of SiC or Al2O3 particles on these processes and the formation of ZnCo–SiC and ZnCo–Al2O3 electrocomposites. Zn electrodeposition shows a well-defined pre-bulk region, where the hydrogen evolution reaction (HER)
and Zn underpotential deposition (upd) compete. Zn bulk electrodeposition begins with primary nucleation and diffusion-controlled
growth, strongly dependent on conditions favoring previous Zn upd against HER. It is assumed that this first bulk process
takes place over the upd Zn. Zn bulk electrodeposition is followed by secondary nucleation and growth. Co electrodeposition
begins with a slow reduction in parallel with HER, followed by a faster reduction. strongly hinders the initial reduction. The ZnCo and Zn electrodeposition curves are initially similar, retaining features of pre-bulk and bulk Zn electrodeposition. 相似文献
18.
Kang Shanjiao Dou Tao Li Qiang Duan Aijun Zheng Yanying Pan Huifang 《Journal of Porous Materials》2008,15(2):159-162
This paper presents the direct synthesis of super-low SiO2/Al2O3 ratio zeolite beta molecular sieve through a novel route, by which some of aluminium species are added during crystaling
process. The IR results show that with the increase of aluminium content in the framework, the frequency of the band in the
range of framework vibration (1060–1090 cm−1) shifts to the lower wave-number; the BET surface-area decreases and the basicity of zeolite becomes stronger. In a second
step, new adsorbents were obtained by solid-state ion exchanging zeolite beta with Cu(I), Ag(I) cations. The deep-desulfurization
(sulfur levels of <1 ppmw) tests were performed using fixed-bed adsorption technique, the sulfur content of the treated and
untreated gasoline was analyzed by microcoulometry. The experimental results show that the desulfurization performance of
sorbents decreases in order: Cu(I)beta > Ag(I)beta > Na-beta. The best sorbent, Cu(I)beta, has breakthrough adsorption capacities
of 0.236 mmolS/g of sorbent for model gasoline. 相似文献
19.
20.
The maximization of the total surface area of Pt-SnO2/Al2O3 catalyst was studied by using the Taguchi method of experimental design. The catalysts were prepared by sol-gel method. The
effects of HNO3, H2O and aluminum nitrate concentrations and the stirring rate on the total surface area were studied at three levels of each.
L9 orthogonal array leading nine experiments was used in the experimental design. The parameter levels that give maximum total
surface area were determined and experimentally verified. In the range of conditions studied it was found that, medium levels
of HNO3 and H2O concentration and lower levels of aluminum nitrate concentration and stirring rate maximize the total surface area. 相似文献