CHOLLON, Georges

doi:10.1016/j.jeurceramsoc.2020.08.066

Laboratoire des Composites Thermostructuraux [LCTS]

Langue

Article de revue

Ce document a été publié dans

Journal of the European Ceramic Society. 2021, vol. 41, n° 1, p. 136-147

Résumé en anglais

This contribution aimed at developing a treatment under ammonia in order to eliminate free carbon from the surface of SiC-based fine ceramics like fibers or coatings. The reaction of NH3 with graphitic and non-graphitic carbon was first investigated through kinetic measurements, in situ gas phase analysis and physicochemical investigations of the solid. The carbon etching rate is controlled by heterogeneous reactions involving active sites arising from bulk structural defects and the formation of HCN. A selection of SiC-based fibers and coatings with various carbon contents and (micro)structures was treated in ammonia in favorable conditions. The analyses of the tested SiC–C specimens revealed a reduction of the free carbon content and, simultaneously, a nitridation of the initial Si–C–(O) continuum over a reaction layer. The growth rate, composition and the volume change of this layer vary with the initial microstructure. The ammonia treatment is able to restore the adhesion of carbon-contaminated surfaces.< Réduire

Mots clés en anglais

Ammonia

Graphite

Carbon

Silicon carbide

Heterogeneous kinetics

Mechanical properties

URI

https://oskar-bordeaux.fr/handle/20.500.12278/124052

DOI

http://dx.doi.org/10.1016/j.jeurceramsoc.2020.08.066

Unités de recherche

Laboratoire des Composites Thermo Structuraux (LCTS) - UMR 5801

Voir/Ouvrir

Métadonnées

Partager cette publication !

Licence d’utilisation du document

The high temperature reaction of ammonia with carbon and SiC–C ceramics

Langue

Ce document a été publié dans

Résumé en anglais

Mots clés en anglais

URI

DOI

Unités de recherche