Phase transitions and isothermal equations of state of epsilon hexanitrohexaazaisowurtzitane (CL-20)

• Published in: Journal of applied physics 2008-10, Vol.104 (8), p.083509-083509-5
• Main Authors: Gump, Jared C., Peiris, Suhithi M.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.2990066

The phase stability of epsilon hexanitrohexaazaisowurtzitane at high pressure and temperature was investigated using synchrotron angle-dispersive x-ray diffraction experiments. The samples were compressed at room temperature using a Merrill-Bassett diamond anvil cell. For high-temperature compression experiments a hydrothermal diamond anvil cell developed by Bassett was used. Pressures and temperatures of around 5 GPa and 175 ° C , respectively, were achieved. The epsilon phase was determined to be stable under ambient pressure to a temperature of 120 ° C . A phase transition to the gamma phase was seen at 125 ° C and the gamma phase remained stable until thermal decomposition above 150 ° C . Pressure-volume data for the epsilon phase at ambient and 75 ° C were fitted to the Birch-Murnaghan formalism to obtain isothermal equations of state.