Surface Singularity Upon Solar Radiation Heating of Graphite/Tungsten Powder Mixture Compacts to Temperatures in Excess of 1600°C

Abstract:

Synthesis of single-phase tungsten sub-carbide W2C was attempted by heating pellets made out of a source of carbon (graphite-G) and W powders with G/W atom ratio between 0.35 and 0.50 to two target temperatures, namely 1600°C and 1900°C in an argon atmosphere using a solar furnace at PROMES-CNRS in Odeillo (France). The results showed that synthesis of single-phase W2C phase was difficult at either target temperature yielding the W2C co-existed with free metallic W. It was noted that the thin top surface layer of the solar-synthesised tungsten carbide pellets heated to 1900°C was distinguishable from the rest of the bulk specimen showing localised growth of nano-meter scale WC whiskers over W2C grains. Detailed XRD (X-ray diffraction) results on the effect of both G/W ratio and temperature on W2C lattice parameters are discussed.

• Periodical: Materials Science Forum (Volumes 587-588)
• Pages: 993-997
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.587-588.993
• Online since: June 2008
• Authors: Fernando A. Costa Oliveira, Bernard Granier, J.M. Badie, Jorge Cruz Fernandes, Luis Guerra Rosa, Nobumitsu Shohoji
• Keywords: Hard Metals, Solar Heating, Synthesis, Tungsten Sub-Carbide

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