Influence Of Nano-aluminum Powders On HMX’s Explosive Performance

HMX is one of the very common energetic materials widely used in military and civilian. It has a high detonation velocity, high density, strong heat resistance, often used in mixed explosives, high-energy propellant, propellant, composite propellant and so on. Aluminum powders have advantages of a very high heat of oxidation and a wide range of sources, and the post-detonation burning effect is very powerful, so they have been used in high power of mixed explosives formulation such as aluminized explosive, thermobaric explosive as metal has high calorific value combustible agent, and nano-aluminum powders have a higher combustion effect Therefore, the impact of nano aluminum explosive performance of HMX is also very meaningful.This experiment studies the variation of HMX powders’ minimum ignition energy and lower explosion limit under conditions of the different concentrations and particle size, also we studied the influence of nano-aluminum on the HMX explosive performance.The test totally select particle size three kinds of HMX including 7μm, 38μm, 70μm and 50 nm, 200 nm, 800 nm nano aluminum powders some conclusions are obtained as follows:(1) Dust concentration is one of the main factors HMX minimum ignition energy, minimum ignition energy of HMX dust concentration increases, decreases and then increases after the first, the presence of concentrations of extreme value. When the minimum ignition energy of HMX achieves the minimum value, the dust concentration is 750g/m3, and at this time three kinds of dust particle size HMX’s minimum ignition energy respective are 25.9m J, 73 m J, 102 m J. Three kinds of dust particle size HMX’s minimum ignition energy fitting curve is a linear relationship. When the dust particle size is 7μm, the dust sensitive concentration and the minimum ignition energy respective are 757.3g/m3 and 28.92 m J. The effects of dust particle size on HMX minimum ignition energy is also very significant, with the increase of the HMX dust particle size, the minimum ignition energy under the dust concentration also largen. The change curves of 7μm, 38μm, 70μm particle size HMX dust have been fitted in this experiment, after calculation the sensitive concentrations of three kinds of dust particle size HMX dust respective are 757.3g/m3、741.827g/m3、742.926g/m3, and the values of the minimum ignition energy respective are 28.92 m J,84.881 m J,109.78 m J.(2) In the fixed ignition energy conditions, the lower explosive limit concentrations of three types of HMX powder particle size was determined, the results are 145g/m3、170g/m3、210g/m3. By comparing the results, the higher explosive limit concentration increases with the increasing of HMX powder particle size. The reason is associated with the specific surface area and the dispersion of powder.(3) The experiments selected 50 nm, 200 nm, 800 nm of aluminum powders, the effects of particle size and the content of aluminum on minimum ignition energy, lower explosion limit of HMX was studied. Aluminum ratio rise from 20% to 40%, the minimum ignition energy of mixed dust has a downward trend, falling from 99.4m J to 73 m J. Then, with increasing aluminum content, the minimum ignition energy of mixed dust in a upward trend, mainly due to lack of oxygen and reduction caused by the relative content of HMX; When the particle sizes of aluminum powder are 50 nm, 200 nm, 800 nm, the minimum ignition energy of dust mixed gradually increased, mainly due to the aluminum surface area increases as size decreases, little and slow release of energy supply leaded; Aluminum powder size increases, lower explosion limit of dust mixing also becomes large, analyzing the reasons similar with the increased ignition energy. Within a certain range of concentrations of aluminum, the higher aluminum concentration, the lower explosion limit of HMX When the aluminum content increases within a certain range, HMX explosive limit reduce.