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After the formation of a concentration gradient of SiC within a carbon-carbon composite, a zircon (ZrSiO 4 ) thin film was coated on the surface. Oxidation-resistance tests of the treated C-C composites were then carried out. A concentration gradient of SiC was produced by heating the C-C composite in silicon powder at 1450°C for 3 hours. The concentration of SiC along the direction of...
Carbon fibers 6.5 μm in diameter were coated with amorphous SiC films by chemical vapor deposition at temperatures as low as 800-900°C, using triisopropylsilane in hydrogen. The morphology of the films was strongly affected by the reaction conditions. The tensile strength of the coated fibers was decreased by the coating, but was little affected by the coating method if smooth and tight films were...
A coating of boron carbide on carbon fibres was found to be a suitable method for preventing the chemical reactions between the fibre carbon and an aluminium matrix during the fabrication of a composite material by a squeeze-casting process. Such a coating is also interesting since it has an excellent oxidation resistance. Unfortunately, the mechanical properties of composites are not always reproducible;...
Silicon carbide/carbon multi-layered coatings have been formed on the surfaces of C/C composites. The multi-layered coatings were deposited by the CVD method at 1200 o C using SiCl 4 , C 3 H 8 and H 2 gases. The principal idea of the present multi-layered coatings is to suppress the through-the-thickness coating cracks by making the thickness of each SiC and...
Carbon coated monoliths have been prepared by dipcoating cordierite monoliths in a polymer mixture and subsequent carbonisation and activation. Preparation parameters that were varied were viscosity of the dipcoating mixture, carbon precursor and carbonisation temperature. Two different polymers have been used as carbon precursors, Novolac and Furan resins. Also monoliths have been coated with slurry...
Fine particles of photocatalytic anatase-type TiO 2 prepared through hydrolysis of titanium-tetraisopropoxide were coated by carbon through their precipitation in poly(vinyl alcohol) (PVA) aqueous solution, followed by heat treatment at high temperatures of 400-1000 o C in a flow of high purity Ar. Without carbon coating, the phase transformation from anatase to rutile started above...
The multi-walled carbon nanotubes (MWCNTs, mean diameter: 100–200nm) with nickel–phosphorous (Ni–P) coatings were obtained by an electroless deposition process. To prepare the MWCNTs covered with continual Ni–P layers, a pre-treatment procedure comprised of acid-cleaning, sensitization and activation has been developed. The resulting MWCNTs have a uniform distribution of the Ni–P layers coated on...
Carbon-coated anatase-type TiO 2 was prepared by the heat treatment of powder mixtures of photocatalyst TiO 2 (ST-01) with different carbon precursors, poly(vinyl alcohol), hydroxyl propyl cellulose and poly(ethylene terephthalate), at a temperature between 700 and 900°C for 1h in an Ar gas flow. Since the carbon layers formed on the TiO 2 particles were porous, the samples...
Negative electrodes of lithium–ion batteries are generally based on graphite. Higher storage capacities can be obtained with disordered carbons, however they demonstrate a noticeable hysteresis and irreversibility, which can preclude a practical application. In this paper, the main parameters which may affect the irreversible capacity are analyzed and we show that the irreversible lithium consumption...
The penetration of titanium tetraisopropoxide (TTIP) dissolved in supercritical CO 2 into the nano-spaces of an activated carbon was studied for the preparation of a TiO 2 -coated activated carbon. The conversion of TTIP to TiO 2 through thermal decomposition was confirmed by evolved gas analysis during heat treatment under a N 2 flow. Acetone was detected in the evolved...
Carbon nanotube (CNT) reinforced hydroxyapatite composite coatings have been successfully fabricated by laser surface alloying. The phase compositions and the microstructure of the composite coatings were studied using X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). TEM observation showed that a large...
Mesoporous carbon–ceramic honeycomb monoliths were prepared for catalyst supports by a polymer blend approach. In these monoliths, vanadium was supported by ion exchange of the cationic precursor with the protons of oxygenated surface groups. Previously to vanadium incorporation, the carbon–ceramic monoliths were oxidized using different agents under various conditions to get different oxidation degrees...
A new method to coat Fe nanoparticles with carbon by pyrolysis of acetylene is reported. The Fe nanoparticles were beforehand coated with silica layers by sol–gel combined hydrogen method. The antioxidation capability of Fe/SiO 2 composites has enhanced greatly after coated with amorphous carbon shells. By the introduction of only 7.5wt.% nonmagnetic silica and carbon, these composites have...
Single-walled carbon nanotubes (SWNTs) were decorated with Au, Pt and Rh nanoparticles coated with oleylamine. This modification improves substantially the colloidal dispersion of SWNTs in chloroform and other organic solvents affording stable organosols for realistic applications. The metal nanoparticles are well dispersed on the external surfaces of carbon nanotubes and among else could be used...
Ceramic foam substrates of various porosities were coated with novolak resin, which was then subsequently carbonised and activated to develop a pore structure. The carbon forming the layer was characterised by thermal analysis, TPD and N 2 , CO 2 and hexane vapour adsorption. It was found to be microporous with a high surface area (up to 1400m 2 g −1 ), which made it...
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