Boron Carbide Deposition Through High Power Impulse Magnetron Sputtering for Inertial Confinement Fusion Targets

There is an increasing demand for thin- and thick-walled, gas impermeable ablators for inertial confinement fusion (ICF) experiments. Various materials have been considered for the capsules such as high-density carbon, beryllium, tungsten, and molybdenum. One potential coating material is boron carbide (B₄C) with some advantages over other materials because of its low mass, allowing for rapid compression, and moderate melting temperature, allowing for amorphous, uniform ablation. Currently, boron carbide coatings for ICF capsules are produced using DC magnetron sputtering or RF magnetron sputtering, but have issues with inhomogeneity and low density. High power impulse magnetron sputtering (HiPIMS) is a promising magnetron sputtering method that has been shown to produce very dense, uniform coatings. This work explores HiPIMS as a method to produce improved B₄C capsules with homogeneous, dense, and gas-impermeable coatings. This work aims to show the material properties of B₄C capsules produced using HiPIMS and plasma parameters necessary to create leak-tight coatings.