Authors
Abstract
A novel method of studying oxidation resistance and phase transformation of SiC fine powder was performed using multiple shock treatments in millisecond timescale using indigenously developed material shock tube (MST1). MST1 was used to produce shock waves which heat the ultra high pure oxygen test gas to a reflected shock temperature and pressure of about 5300 K (estimated) and 25 bar, respectively for 1-2 milliseconds. Different characterization techniques like X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) show the formation of oxides and sub-oxide species after shock treatment. XRD studies shows the phase transformation of hexagonal SiC to amorphous SiO2. SEM and TEM micrographs show change in surface morphology of SiC from irregular shape to micro/nano spheres due to superheating and cooling at the rate of about 106 K/s. This novel method is used for the first time to demonstrate the behavior of material in presence of extreme aero-thermodynamic conditions for a short duration. These conditions generated using shock tubes are not achievable by conventional furnaces for oxidation studies of SiC in a short duration.
Graphical Abstract
)
Keywords
)