We are using MWCNTs as reinforcement in silicon nitride and SiO2, densifying it at higher temperature 1700 C in nitrogen gas environment. Does MWCNTs react/oxidize with SiO2 and Si3N4 at higher temperature and produce CO/CO2 gases?
Where are your CNTs from? How have they been treated in the process. If what you are saying is happening, then I would say it is from absorbed/trapped gases rather than the other two components you mentioned.
Yes, they can be oxidized, only we have to carryout the process in the presence of sufficient air.
SiO2 and carbon actually can produce SiC at the temperatures higher than 1600C, I guess, but in order to produce CO/CO2 from carbon and Si3N4 you need at least some oxygen-containing compomponents such as air admixture or SiO2.
@SergeiChernyk Thank you for your answer. Yes, SiO2 phase is present during sintering at 1700. I would like to ask how can we confirm the formation of such gases during this process?
Awais Qadir , you can confirm it both directly (by IR or MS of outlet gases) or indirectly (Si-C bond detection by XPS).
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