Laser-driven Microparticle Impact Experiments on Reinforced Carbon-Carbon, Graphite, and Silicon Carbide

Thermal Protection System (TPS) materials in hypersonic flight not only endure extreme aerothermal loads but are also subject to harsh atmospheric conditions where particulates of sand, ice, or volcanic ash can cause spallation damage and erosion. In this study, a laser induced particle impact testing (LIPIT) method is used to investigate the high-speed impact of microparticles on a range of TPS materials. Monodisperse alumina microspheres with nominal diameters of 60 μm are accelerated to velocities of up to 520 m/s and are impacted on ultra-fine grain graphite, 2D woven reinforced carbon-carbon (RCC), and sintered silicon carbide (SiC) targets. The cratering and spallation mechanisms and their extent for graphite and RCC are studied in situ via high-speed imaging and postmortem using scanning electron microscopy (SEM) and digital confocal microscopy. For silicon carbide experiments, no discernible surface damage was observed and the alumina projectiles were found to fragment upon impact.