Diamond formation in double-shocked epoxy to 150 GPa

• Published in: Journal of Applied Physics
• Main Authors: Marshall, M. C., Gorman, M. G., Polsin, D. N., Eggert, J. H., Ginnane, M. K., Rygg, J. R., Collins, G. W., Leininger, L. D.
• Other Authors: U.S. Department of Energy, University of Rochester, New York State Energy Research and Development Authority, Lawrence Livermore National Laboratory
• Format: Article in Journal/Newspaper
• Language: English
• Published: AIP Publishing 2022
• Subjects: General Physics and Astronomy; Methane hydrate
• Online Access: http://dx.doi.org/10.1063/5.0082237; https://aip.scitation.org/doi/am-pdf/10.1063/5.0082237; https://pubs.aip.org/aip/jap/article-pdf/doi/10.1063/5.0082237/16504672/085904_1_online.pdf

We present measurements of diamond formation in doubly shocked Stycast 1266 epoxy (comprising C, H, Cl, N, and O) using in situ x-ray diffraction. Epoxy samples were reshocked against a LiF window to pressures between 80 and 148 GPa in experiments at the Omega Laser Facility. The pressure and temperature conditions were diagnosed in situ using velocimetry and optical pyrometry, respectively. X-ray diffraction patterns of the compressed epoxy are consistent with cubic diamond (Fd3¯m), indicating that diamond can precipitate not only from twice-shocked CH polystyrene [Kraus et al. Nat. Astron. 1, 606 (2017)] at these conditions but also from twice-shocked CH polymers with the addition of oxygen, nitrogen, and chlorine. These results, in combination with previous works on CH, CH2, CH4, and methane hydrate, support that diamond often, but not always, forms from CH-based compounds at extreme pressures and temperatures, indicating that the chemical composition, thermodynamic compression path, and kinetics play an important role.