| With the continuous development of modern science and technology as well as national defense construction in order to meet modern warfare.The demand for new types of weapons and ammunition places high demands on the energy characteristics and safety characteristics of future weapons.Experts from various countries are also committed to the research of new high-energy and low-intensity explosives.1,1-Diamino-2,2-dinitroethylene?FOX-7?was synthesized under this circumstances.As a new type of high energy and low-sensitivity explosive,FOX-7 is widely concerned in the world and has a good application prospect in insensitive ammunition.It is one of the hot topics in the field of energetic materials in recent years.In this paper,the minimum ignition energy and the lower explosion limit of the FOX-7dust cloud are measured using a 1.2-L Hartmanm tester and a 20 L explosion sphere vessels,and measure the minimum ignition energy at different ratios with AL powder.Then,use DSC-TG synchronous thermal analyzer to analyze the thermal decomposition process and curves of FOX-7.The kinetic parameters and thermodynamic parameters were calculated.The critical explosion temperature of FOX-7 was estimated based on the experimental data.The results showed that:?1?Set the diffusion pressure to 0.7Mpa,FOX-7 dust particle size to 25um,and the corresponding concentration is 100g/m3,200g/m3,400g/m3,600g/m3,800g/m3,1000g/m3.The minimum ignition energy of the test dust cloud was:112mJ,79.85mJ,40.74mJ,36.53mJ,25.66mJ,19.01mJ.When the diffusion pressure and the dust particle size are the identical,the minimum ignition energy of the FOX-7 dust cloud gradually decreases with the increase of the dust concentration,and eventually becomes flat.?2?When the diffusion pressure is 0.7Mpa,the FOX-7 dust and the AL powder are mixed in a certain proportion.With the increase of the aluminum powder content,the minimum ignition energy of mixed dust presents the trend of decreasing first and then increasing.The most suitable ratio is70%FOX-7+30%AL.The corresponding minimum ignition energy is 15.65mJ.?3?According to measurement,the lower explosion limit of FOX-7 is 70g/m3—90/m3.?4?According to the results of DSC-TG simultaneous thermal analysis,the decomposition process of FOX-7 is divided into two stages.With the increase of heating rate,the decomposition initiation temperature,peak temperature and decomposition end temperature of FOX-7 are all increased as well as the maximum rate of weight loss.The two decomposition peak temperatures at the heating rates of 5K,10K,15K and 20 K/min were220.35?,225.8?,229.45?,232.75°C and 292.2?,292.3?,292.4?,292.75°C,respectively.?5?Based on the DTG curve,the apparent activation energies calculated by the Kissinger method and the Ozawa method were 205.9 kJ/mol and 203.7 kJ/mol,respectively,and the lgA measured by the Kissinger method was 21.5.Based on the DSC curve,the apparent activation energies calculated by the Kissinger method and the Ozawa method were225.8 kJ/mol and 222.5 kJ/mol,respectively,and the lgA measured by the Kissinger method was 23.7.?6?It can be known from the calculation that the critical temperature for FOX-7 thermal explosion is 208.37°C.?7?Through mass spectrometry analysis of the products of the thermal decomposition reaction of FOX-7;NO,NH3,N2O,HCN,and other products are produced in the two decomposition stages,and NO2,HNCO,etc.are basically produced only in the second stage. |
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