Significantly different inhibition mechanisms of graphene oxide in laser-ignited combustion of micro and nano CL-20

Because of its high energy density, hexanitrohexaazaisowurtzitane(CL-20) has been widely used in propellants in place of conventional oxidizers. The adjustable burning rate of the CL-20 is a key factor in adapting the propellant to various environments. In this work, the effects of graphene oxide(GO) content on the thermal release, ignition and combustion characteristics of micro and nano CL-20 were thoroughly conducted based on the differential scanning calorimetry measurements (DSC), laser ignition, burning rate test and condensed combustion products collection. The results show GO has a positive effect on micro and nano CL-20 in ignition performance and a negative effect on combustion rate. Owing to the addition of GO, the original flameless combustion of CL-20 changes to flaming combustion. With increasing GO content, the burning rates of micro and nano CL-20 show completely different descending laws. Furthermore, the combustion mechanism of nano and micro CL-20/GO has been studied in detail. The burning rate of micro CL-20/GO is primarily determined by the condensed phase, and that of nano composite is controlled by both of the condensed and gas phases. This work provides a deeply insight into the influence mechanism of GO on the properties of nano and micro CL-20.