250 / 2023-04-20 19:39:18

The peculiarity of Boron Nitride Hugoniot by laser shock compression up to 1.6 TPa

phase diagram,high pressure,shock wave

高压物理与材料科学 > 动高压-海报

As a low-Z chemical element, Boron and boron compounds are very important both in the astrophysical context and in the study of nuclear fusion. From the point of view of Inertial Confinement Fusion, Boron nitride (BN) have been proposed as alternative ablator[1] comparing CH and high density carbon [2], because it could enable better coupling between the laser and capsule. From the point of view of material science, the phase diagram of BN predicted is similar to that of carbon, incorporating phases [3-4] at high temperatures and pressures whose structures and physical properties resemble diamond. The Hugoniot peculiarity of BN with different phases is significantly different, and experimental data are needed to verify the theoretical model. Only few experimental data for Hugoniot and melting properties at high pressure and temperature [5] have been obtained and they are too limited for constraining these theoretical models above a few hundred gigapascals. 

Here we reported first shock Hugoniot experimental results for hexagonal BN at pressure between 500 and 1600 GPa (516 Mbar). At SGIII prototype laser facility in China, hexagonal BN has been compressed near threefold compression using hohlraum radiation-generated shock waves. Our pressure and density measurements of BN at extreme conditions are in good agreement with the results by density functional theory molecular dynamics (DFT-MD) simulations and theoretical predictions. The results are also benefit for understanding its structural complexity in phase diagram and how phase changes upon compression and provide more fundamental scientific information for BN phase diagram at high pressures and practical interest for ICF and high-energy density physics.