Proceedings of the 9^th SolarPACES International Symposium on Solar Thermal Concentrating Technologies
STCT 9

J. Phys. IV France 09 (1999) Pr3-405-Pr3-410
DOI: 10.1051/jp4:1999363

Influence of gas environment on synthesis of silicon carbide and some carbides and carbonitrides of d-group transition metals through reaction between metal powders and amorphous carbon powders in a solar furnace at P.S.A. (Plataforma Solar de Almería)

D. Martinez,¹, J. Rodríguez¹, L. Guerra Rosa², J. Cruz Fernandes² and N. Shohoji<sup>3

1</sup>  Plataforma Solar de Almería (PSA), Centro Europeo de Ensayos de Energía Solar, Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, P.O. Box 22, 04200 Tabernas, Spain
²  Instituto Superior Técnico (IST), Departamento de Engenharia de Materiais, Av. Rovisco Pais, 1096 Lisboa codex, Portugal
³  Instituto Nacional de Engenharia e Tecnologia Industrial (INETI), Instituto de Materiais e Tecnologias de Produção, Departamento de Tecnologias de Produção, Estrada do Paço do Lumiar, 1699 Lisboa codex, Portugal

Abstract
Refractory carbides and carbonitrides including silicon carbide SiC, tungsten carbide WC, titanium carbide TiC_x (0.5<x<l) and titanium carbonitride TiC_xN_y (0.5<x+y<l) were synthesised from compacted pellet composed of metal powders and amorphous carbon powders through heating in a solar furnace under controlled atmosphere (Ar or N₂). Under irradiation of the solar energy flux 1,350 kW/m² (ca. 1650°C in terms of measured temperature) for 30 min in Ar atmosphere, Si, W and Ti were converted to SiC, WC and TiC_x, respectively. By the similar reaction undertaken in N₂ atmosphere, Si and W were converted to SiC and WC, respectively, but carbonitride TiC_xN_y formed from Ti. No special influence of atmosphere was detected on the WC formation, but conversion to SiC from Si was somewhat retarded in N₂ atmosphere. In either Ar or N₂ atmosphere, progress of graphitisation of amorphous carbon was not detectable by X-ray diffraction analysis in the reaction with Si and Ti but graphitisation of amorphous carbon appeared to be significantly accelerated in the reaction with W.

© EDP Sciences 1999