Surface Oxidation Study of ZrB2–SiC Composite for Re-entry Applications Using Free Piston-Driven Shock Tube

Abstract

Free piston driven shock tube (FPST) is used to perform experiments with ultra high temperature ceramic composites (UHTC). In the present work ZrB2-SiC composite samples are tested in the form of pellets. The pellets were mounted at the end flange of the shock tube and exposed to reflected shock waves in presence of oxygen test gas. Ultra high pure (UHP) oxygen at 10 kPa pressure, heated to very high temperatures of about 9000-10000 K (estimated) and reflected shock pressures of about 6.5-8 MPa for 2-3 ms duration interacts with the surface of ZrB2-SiC ceramic. The surface oxidation occurring on the composite materials has been studied extensively, before and after exposure to shock heated oxygen. Different characterisation techniques like scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) etc. are used to understand the catalytic and non-catalytic surface reactions by examining the surface morphology, electronic structure and crystal structures of the shock treated samples.