Effect Of Mg（BH₄）₂ On Thermal Stability Of Several RDX-based Mixed Explosives

Metal hydride as the additive of mixed explosives is one of the hot topics in the field of energy-containing materials,so the study on the safety between metal hydride and energy-containing materials has become the focus of the research.In this paper,Mg（BH₄）₂ was choosed as a metal hydride additive,then added Mg（BH₄）₂ to Desensitized RDX,Desensitized RDX/Al and Desensitized RDX/Al/AP mixed explosives respectively.The effects of Mg（BH₄）₂ on the thermal stability of several RDX-based explosives were studied by differential scanning calorimetry（DSC）,adiabatic accelerated calorimetry（ARC）and vacuum stability test（VST）.The DSC can obtain the thermal decomposition curve of the sample and visually see the change of the exothermic process of the sample.And DSC can judge the inter-material compatibility according to the change of the temperature of decomposition peak,and according to the experimental data at different heating rise,the values of apparent activation energy E and pre-exponential factor A of the samples were calculated.ARC can obtain more accurate exothermic information of samples,and also obtain relevant parameters such as heat release and adiabatic temperature rise under adiabatic conditions.VST can judge the stability and compatibility of the mixture.Through the above experiment to the following conclusion:The influence of Mg（BH₄）₂on the thermal stability of Desensitized RDX is related to the mass ratio of Mg（BH₄）₂.When the mass ratio is 10%,it can not only reduce the possibility and severity of thermal runaway risk,but also have good stability,which is more difficult to occur thermal decomposition.However,when the mass ratio increases to 20%,the thermal stability becomes significantly worse.The addition of Mg（BH₄）₂ can significantly increase the exothermal performance of Desensitized RDX/Al mixed explosives,and the possibility and severity of thermal runaway risk also increase,but the mass ratio of Mg（BH₄）₂ increases from 10%to 15%,and the vacuum stability of mixed explosives is good.When Mg（BH₄）₂ was added to Desensitized RDX/Al/AP explosives,the stability became worse.In addition,if add Al and Mg（BH₄）₂ as additives to Desensitized RDX/AP,the three mixed explosives are ranked from the highest to the lowest in terms of thermal stability:the mixed explosive containing Al>the mixed explosive containing Mg（BH₄）₂>the mixed explosive containing Al and Mg（BH₄）₂.Through the experiments in this paper,the thermal stability of Mg（BH₄）₂ on several RDX-based mixed explosives is preliminarily analyzed,which has certain guiding significance and reference value for the practical application of Mg（BH4）2 in energy-containing materials.