I heated fine quartz sand with crushed charcoal with an electric arc (welder + carbon rods, about 1.5-2kW) for a few times, each time 1-2 minutes and
adding some charcoal + sand intermediate. It heated to at least 2000-2500C.
I saw very small spheres during the arcing.
After cooling down I still see these very small spheres (<1mm dia) on the charcoal. See here a movie of the cooled matter (image size about 30mm
wide).
No, I don't have scales which weigh sub-milligram quantities and sub-cubic millimeter volumes. chornedsnorkack - 12-10-2014 at 10:04
The densities are 2,33 for Si and 3,21 for SiC.
Are there any liquids with density in that range, which do not react with either Si or SiC?Praxichys - 13-10-2014 at 08:43
I would imagine that since they are spheres, some melting had to occur.
Silicon melts at 1414C
SiO2 melts at ~1700C
SiC melts at 2730C
Even in an arc, I find it unlikely that the SiC would have melted to form beads like that. That's almost 5000 degrees F.
You might be able to test it using hardness. SiC is very hard. You may be able to find a piece of hardened steel that quartz and silicon cannot
scratch, but SiC would. This could be a good small scale test.
I do not know much about the chemical stability of SiC but perhaps digesting in molten NaOH and then some strong acid would get rid of anything but
the SiC?etoxiran - 12-6-2015 at 13:50
