Carbon Fibers and Nanotubes as a Product of Interaction between Silicon Carbide and Carbonate Melt

Tuesday, 7 October 2014
Expo Center, 1st Floor, Center and Right Foyers (Moon Palace Resort)
S. V. Devyatkin (Institute of General and Inorganic Chemistry)
In quite a number of works, the corrosion of SiC with molten carbonates was studied, but the products of this interaction were not investigated [1, 2]. In this work, the interaction of silicon, TiC and SiC (F 14 and F 36) powders with Na2CO3-K2CO3 melt at 7500С in Ar atmosphere and in air was studied. After washing, the interaction products were analyzed on a SEM and by Raman spectroscopy. A thermodynamic evaluation of the reactions proceeding in carbonates showed that the Gibbs energy for reactions given below is negative at 1023 K; if follows that the reactions proceed from left to right:

I.    3Si + 2Na2CO3 = 2C + 4Na + 3SiO2

                ΔGo1023 K = -473 kJ

II. 3SiC + 2Na2CO3 = 5C + 4Na + 3SiO2

                ΔGo1023 K = -277 kJ                      

III. 3TiC + 2Na2CO3 = 5C + 4Na + 3TiO2

            ΔGo1023 K = -54 kJ                       

Were silicon interacts with carbonate melts, a large amount of graphite and carbon black is formed, which complicates the process of separation of reaction products. Because titanium oxides are slightly soluble in carbonate melts, the surface of carbon fibers was coated with this reaction product. Silicon oxide are readily soluble in carbonate melts, therefore the most promising method for the fabrication of carbon fibers and nanotubes is interaction between SiC and carbonate melts. When SiC interaction with molten carbonates, both carbon fibers and nanotubes are formed (Fig. 1.). Raman spectroscopy corroborated the presence of carbon fibers in the products.


1.   R. E. Dial, G.E. Mangsen,  Corrosion, 17,  35t  (1961).

2. R.E. Tressler, M.D. Meiser, T. Yonushonis,  J. Am. Ceram. Soc., 59,  278 (1976).

Fig. 1. SEM micrograph of SiC (F14) powder after 2 hours interaction with carbonate melts at 7500C .