| Autor: |
Jorge Cruz Fernandes, Bernard Granier, Jean-Marie Badie, Fernando A. Costa Oliveira, Luís Guerra Rosa, Nobumitsu Shohoji |
| Rok vydání: |
2007 |
| Předmět: |
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| Zdroj: |
International Journal of Refractory Metals and Hard Materials. 25:101-106 |
| ISSN: |
0263-4368 |
| Popis: |
At around 1600 °C, stable phase in W–C binary system being in equilibrium with excess carbon is acknowledged to be mono-carbide WC. Nevertheless, during carbide formation from mixed powders of tungsten and excess carbon (C/W atom ratio: 2) in inert Ar gas environment, sub-carbide W 2 C formed besides mono-carbide WC when the heating was done extremely rapidly (instant temperature rise to 1600 °C from ambient temperature within fractions of a second) in a solar furnace at PROMES-CNRS in Odeillo (France) and the formed W 2 C resisted to be converted fully to WC even after 30 min heating at a temperature exceeding 2500 °C in Ar gas. Under comparatively fast heating condition (heating from ambient temperature to 1600 °C in about 1 min) realised in a solar furnace at PSA (Plataforma Solar de Almeria) in Tabernas (Spain), equilibrium phase WC alone formed from the similar starting material (C/W atom ratio: 1.5). Consideration is given for the formation mechanism of W 2 C under the eruptive heating condition in the solar furnace at PROMES-CNRS and also for the meta-stability of the formed W 2 C phase. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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