Shock induced bottom up formation of silicon carbide (SiC) nanodust
Arijit Roy, V S Surendra, M Ambresh, R Ramachandran, J K Meka, V Venkatraman, T Vijay, K K Marhas, A Das, V Thirukumaran, P Janardhan, B N Rajasekher, Anil Bhardwaj, N J B MasonSivaramanAbstract
Silicon carbide (SiC) dust plays an important role in the interstellar molecular enrichment process by providing a finite area for surface chemistry to take place. Its robust presence in different parts of interstellar medium (ISM) and circumstellar medium (CSM) has been routinely traced by observations at the mid-infrared wavelength. It is one of the most well studied dust grains observed as a component of presolar grains in the meteorite. In this work, we experimentally investigated the bottom up formation pathway of SiC by shock processing of amorphous carbon nanodust and silicon nanopowder with a 2: 1 mass ratio (with mole fraction around 4.7:1)in the presence of hydrogen. The pre and post-shocked samples were examined using techniques including ATR-FTIR spectroscopy, XRD, and HR-TEM imaging. These results show the presence of polycrystalline (α,β) SiC and various carbon nanostructures such as carbon nanoribbons, carbon nanotubes and nanobuds. These results suggest that shock waves, especially low-velocity shock waves, in the ISM/CSM, can induce a chemical reaction between elemental C and Si, leading to the formation of polycrystalline SiC and various other forms of carbon nanostructures simultaneously.