Optimization of boron carbide density using direct current sintering for use as sputtering sources at the National Ignition Facility

Several experimental trials were conducted to determine optimal sintering parameters and compositions for purchased boron carbide powder using spark plasma sintering/direct current sintering.Sputtering targets used to create ablators for the National Ignition Facility have been unable to survive post processing procedures suggesting that in-house fabrication may yield better results due to extended control.This was accomplished through marginal testing of hold temperature, heating rate, target pressure, pressure onset, dwell time, atomic percent carbon black, graphite, and boron to carbon ratio of the powder.Compositional tests involving carbon black, graphite, and boron involved mixing additive powders with boron carbide using a wet mixing technique involving water and then dried overnight within a furnace.The optimal sintering parameters were found to be a hold temperature of 2000 C, a heating rate of 300 C/min, a target pressure of 50 MPa applied in line with typical parameters, and a dwell time of 5 min.Atomic percentages of 0.4% carbon black, graphite, and a boron to carbon ratio of 6:1 yielded the largest relative density for each respective trial.Greater control of the density and composition allows for more dynamic testing of ablators and sputter sources at the National Ignition Facility and therefore more advancements towards fusion research