HNIW or CL20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) is a nitramine, which is considered as the highest energetic molecular compound known to date, therefore, attracting increasing interest in propulsion applications. Additionally, CL20 is an interesting system for fundamental studies, exhibiting several polymorphs, which can behave as host lattices for trapping guest molecules. Herein, a new CL20 structure that contains inserted CO(2) molecules is reported. A combination of Fourier transform infra red (FTIR) spectroscopy, scanning electron microscopy (SEM), single-crystal X-ray diffraction, and thermal analyses (thermogravimetric analysis coupled with mass spectrometry and differential scanning calorimetry) was used to characterize this new material.

Protective coatings (Al-ON and Al-O-B-N) on Si-O-C fibers (Tyranno ZMI) were applied in order to enhance oxidation resistance under severe thermo-mechanical conditions in the 400-600°C temperature range. The coating process consisted in three steps: (i) the transformation of the Si-O-C fiber surface into microporous carbon; (ii) the impregnation of these carbon microporous layers by an aluminium trichloride (AlCl 3) solution and then, (iii) a final heat-treatment under ammonia. Processing parameters were studied in order to select the best conditions. Using these conditions, obtained results have shown that coatings were present around each fiber, with a controlled thickness, and that the mechanical properties of the fibers were preserved. Although, these coatings did not entirely stop the oxygen ingress, it has been shown that they strongly reduced the oxidation of the fiber.