Mechanical property improvement of B4C ceramic hollow microspheres by doping carbon nanotubes at low-temperature

Abstract

Boron carbide (B4C) ceramic hollow microspheres are considered to be a potential ignition capsule for inertial confinement fusion (ICF). B4C hollow microspheres with enhanced mechanical properties were obtained by pressureless calcination at low temperature with the addition of 2 wt% carbon nanotubes (CNTs). Notably, the microstructure of as-prepared microspheres directly reveals the strengthening mechanism is bridge toughening and pullout of CNTs. The density of B4C hollow microspheres reached 73.2% T.D. at 1000 °C when the doping amount of CNTs is 2 wt%. The crush load of B4C ceramic hollow microspheres (2 wt% CNTs) calcinated at 1000 °C is 25.3 N, while the crush load of the undoped samples under the same conditions is only 8.0 N. The improvement of mechanical properties of B4C hollow microspheres reduces the sensitivity of hollow microspheres to hydrodynamic instability in the high-temperature and high-pressure environment during fusion reaction, which can achieve relatively high fuel efficiency. Meanwhile, the B4C hollow microspheres with high surface finish and high strength as ICF target pellets can greatly reduce the influence of hydrodynamics instability on implosion and effectively improve the gain of the target.