The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In order to characterize C/C composites during consumption and to document a carbon–carbon oxidation model, specific oxidation experimental facilities were developed. Two different devices of a BLOx (Bench Laser for Oxidation) feature were designed according to the atmosphere (molecular air, oxygen, water vapor). These facilities enable high-temperature material characterization to be performed in...
In this part a numerical model for the oxidation of C/C composites is developed. It takes into account the morphological and the reactivity results determined in part I and II, respectively. The prediction ability of this model has been checked for different types of composites oxidized in different atmospheres and generally the trends of the experimental reaction curves are relatively well followed...
A model of the oxidation behaviour of C/C composites was developed. The purpose of the model is to predict the carbon loss that occurs at the outer surface and within the porosity of the composite. It takes into account the transport of species in the material, chemical gas–gas and gas–solid reactions, the interaction of both transport phenomena and chemistry, the morphological parameters of the unoxidized...
An evaluation of some of the properties of electrochemically oxidised graphite has been carried out. These studies include textural characterisation, magic angle spinning NMR, ESR and ion exchange properties. A study of the surface morphology has also been carried out using high-resolution transmission electron microscopy and identification of surface groups confirmed by FTIR spectroscopy. The electrochemical...
The enthalpy of immersion of carbons into water reflects the specific and the non-specific interactions between the liquid and the solid. The study of a variety of active carbons oxidized to different degrees with (NH 4 ) 2 S 2 O 8 , HNO 3 and H 2 O 2 , reveals a simple correlation between the enthalpy of immersion, Δ i H(H 2 ...
The oxidation behavior of polyimide-derived carbon films doped with boron in low levels (up to 1.23x10 -2 B/C) was investigated by means of thermogravimetric analysis (TGA). It was observed that boron-doping less than 7.09x10 -3 B/C in the carbon film formed at 1500 o C had a catalytic effect on the oxidation of the carbon. Based on a kinetic analysis, it is revealed...
The effects of oxygen-containing groups, particularly carboxylic and carbonyl groups, on the adsorption of dissolved aromatics on ash-free activated carbon have been studied. Adsorption isotherms for phenol, aniline, nitrobenzene, and benzoic acid were generated in both aqueous and cyclohexane media, using carbons with different amounts of surface oxygen groups. It was found that water adsorption,...
A series of activated carbons with different degrees of activation were oxidized with H 2 O 2 , (NH 4 ) 2 S 2 O 8 and HNO 3 in order to introduce different oxygen surface complexes. Changes in the surface chemistry of the activated carbons after their oxidizing treatments were studied by different techniques including temperature-programmed desorption...
Vapor-grown carbon micro-coils were oxidized under a low O 2 flow-rate for introducing oxygen-containing functional groups on the surface. The surface characteristics were then examined. The O1s/C1s intensity ratios of the XPS spectra measured on the surface increased on using the oxidation treatment. The maximum O1s/C1s ratio of 11.4 at.% was obtained under the following conditions: (a) the...
Three unidirectional C/C composites were prepared from PAN-based carbon fibres and three coal-tar pitches obtained from the same parent coal-tar pitch but differing in their primary QI content. The effect of the amount of primary QI present in pitches on the air reactivity of pitch-cokes and C/C composites was studied by thermogravimetric analysis. The oxidation of pitch-cokes was performed at 10...
Carbon adsorbents with different properties were obtained from furfural with variations in the activation reagents and conditions of treatment. They possess insignificant ash and sulfur contents. Pore volume, pore size distribution and the chemical character of the surface of the obtained carbon adsorbent depend on the activation reagent and temperature of treatment. Various oxygen-containing groups...
A three dimensional C/SiC composite was prepared and flexural strengths during combustion atmosphere and weight changes in air were investigated. When oxidized in air, the C/SiC composite gained weight above the cracking temperature, and lost weight below the cracking temperature. The weight loss reached its maxumum value at about 700 o C. When oxidized during combustion atmosphere, the composite...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.