Study On Thermal Performance Of Boron-hydrogen Compound-ammonia Borane

In order to achieve high-speed and safe flight, the research of the aircraft fuel and rocketpropellant has always acts as a hot issue in the aerospace field. Compared with other metalfuels, boron owns a very volumetric and mass calorific value. Meanwhile, hydrogen wasconsidered to be material which has the highest mass calorific value per unit, and cansignificantly reduce the weight of the propellant. If boron and hydrogen can be combined toeach other to develop a new kind of fuel, it will be able to improve the performance of thefuel significantly. So, the boron-hydrogen compounds have attracted the most attention.Ammonia borane is a kind of molecular crystal constituted by NH3BH3. As a representsubstance of boron-hydrogen compounds, it has a hydrogen content of19.6%by weight andhas moderate thermal stability characteristics, makes that become a very promising addictiveto boron based propellant.The paper summarized the development of the solid propellant and its key components,explored the status quo of the thermal decomposition and thermal aging characteristics of thesolid propellant. The development of the boron-hydrogen which was used as constitute part ofthe high burning rate propellant was emphasized. Then the paper explored the thermalperformance of the ammonia borane in the thermal decomposition kinetics and thermal safetyaspects.The thermal performance of ammonia borane was detected by TG-DSC method andfound ammonia borane is a typical “melt before decomposition” type substance. Itsdecomposition process can be divided into two stages. Isothermal method was used toeliminate the process of melting endothermic in case of impact the exothermic process. Theaverage activation energy and the decomposition enthalpy were calculated by the isothermaldata. Non-isothermal method was used to analysis the decomposition process of ammoniaborane. The most probable mechanism function activation energy and pre-exponential werecalculated by the Popescu, FWO and KAS methods. Kinetic compensation effects ofactivation energy and pre-exponential were also observed. Thermal behavior of ammonia borane and its compatibility with main components ofpropellant were investigated by DSC techniques. The results show that the compatibilities ofammonia borane with AP, HTPB, and RDX are favorable.The AKTS-thermal safety and thermo kinetics software was used to evaluate the thermalstorage security of ammonia borane. Though the thermal dynamic parameters: the reactionactivation energy, self-accelerating decomposition temperature and the time to reach themaximum reaction rate, the thermal safety of ammonia borane and simulated possibleaccident, what this paper offered can deliver some references for industrial production.