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41.
A new approach for preparing of microcellular ceramic materials is the reproduction of wood morphologies by biotemplating, where the structural features of the native wood are maintained in the ceramic product. Biomorphic Al2O3-ceramics were manufactured via the sol-gel route by repeated infiltration of low viscous alumina sols into wood preforms and subsequently sintered in air at 1550°C. The microstructure and phase formation during processing were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), density and porosimetry measurements. In contrast to conventional processed, highly-porous Al2O3-ceramics, the microstructure of the biomorphic Al2O3-ceramics is characterized by an uniaxial pore morphology with pore diameters in the micrometer range, depending on the initially used wood template. 相似文献
42.
The three-way catalyst promoters (Ce-Zr)O2, (Pr-Ce-Zr)O2 and (Pr-Zr)O2 were prepared by the sol-gel method. The reduction/oxidation behavior of these mixed oxides was compared. It is shown that the formation of (Pr-Zr)O2 cubic solid solution at high temperature up to 800 °C makes it more reducible, and that the ternary solid solution that formed in (Pr-Ce-Zr)O2 mixed oxides plays an important role in the reduction process. The catalytic performance tests reveal that the introduction of a small amount of praseodymium into (Ce-Zr)O2 favors the light-off temperature of C3H6 and NO and the effectiveness for NO conversion at the lean region. 相似文献
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本文采用溶胶-凝胶法以组成为3Al2O32SiO2的混合溶胶分别于常压和压力条件下,对SiC微细粉进行包覆处理,该涂覆层在低于1000℃下经1h热处理可结晶成莫来石层,研究了涂覆溶胶浓度、涂覆压力对涂层厚度、结晶化温度等的影响,涂覆后的SiC微粉在中高温的表面抗氧化性明显提高 相似文献
44.
Synthesis and Microstructure of Highly Oriented Lead Titanate Thin Films Prepared by a Sol-Gel Method 总被引:1,自引:0,他引:1
Chiahong Chen Daniel F. Ryder Jr. William A. Spurgeon 《Journal of the American Ceramic Society》1989,72(8):1495-1498
Thin films of PbTiO3 were deposited on fused silica, resistor-grade alumina, and single-crystal (100) MgO by a sol–gel processing method. Whereas the films deposited on silica and alumina substrates were randomly oriented and polycrystalline, highly {100} oriented PbTiO3 films were grown on the MgO single crystals. The perovskite-type structure was observed with films deposited on the single-crystal MgO and annealed at temperatures as low as 470°C, whereas a pyrochlore-type strcuture was observed with films on fused silica and alumina processed in a similar manner. All films heat-treated at temperatures in excess of 570°C showed significant formation of a second PbTi3 O7 phase. The films were characterized by electron microscopy and glancing-incidence-angle X-ray diffraction. 相似文献
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Massimo Guglielmi Giovanna Brusatin Giacomo Facchin Mario Gleria Roger De Jaeger Marco Musiani 《Journal of Inorganic and Organometallic Polymers》1996,6(3):221-236
In this paper the sol-gel preparation of hybrid materials made of metal oxide and polytorganophosphazenel components is described. The main problem focused on during this research was to avoid phase separation in order to get homogeneous materials. This problem was pursued looking at the formation of genuine chemical bonds between the exploited polyphosphazenes and the inorganic composite networks. Investigations on the thermal, mechanical, and electroconductive properties of the synthesized, phosphazene-containing composite materials showed that these matrices presented improved mechanical and thermal features with respect to those of the original phosphazene macromolecule, while the ionic conductivities of the prepared molecular hybrids doped with lithium or silver trillate are of the same order of magnitude as those measured for the neat, original phosphazene substrate.Presented at the Ist Italian Workshop on Cyclo- and Polytphosphazenel Materials. February 15–16, 1996. at the CNR Research Area in Padova, Italy. 相似文献
50.
超临界流体干燥技术制备纳米二氧化锰 总被引:1,自引:0,他引:1
采用溶胶法和超临界流体干燥技术,在533K,7.6MPa的条件下,用超临界乙醇作为干燥剂制备纳米级二氧化锰,采用X射线衍射,透射电镜确定了二氧化锰粒子的行貌和粒径,结果表明,用超临界流体干燥技术可以得到颗粒细,大小均匀,抗团聚非常好的纳米粒子。 相似文献