Study On Preparation And Properties Of Enhanced Perchlorate Based Composite Energetic Materials

It is well known that ammonium perchlorate is often used as oxidant in composite solid propellants,and transition metal oxides as catalysts can improve their thermal decomposition performance.Some studies have also pointed out that adding carbon materials to composite solid propellants can improve their mechanical properties.Therefore,the design and preparation of enhanced perchlorate-based ternary composite energetic materials are proposed,hoping to improve the catalytic performance while improving the mechanical properties of composite solid propellants.The CASTEP module in Materials Studio software was used to simulate the energy band structure.Based on the band gap and catalytic performance,N-type transition metal oxides were preferred.The preferred N-type transition metal oxides were combined with carbon materials to simulate the energy band structure.On this basis,enhanced ternary composite energetic materials were designed and prepared,and their catalytic mechanism was explored.The main research conclusions are as follows:（1）The simulation results show that among the three selected N-type transition metal oxides,Zn O has the strongest catalytic ability,better thanα-Fe₂O₃and Mn O₂.Compared withα-Fe₂O₃and Mn O₂,Zn O has the widest band gap of 0.747 e V,and the d orbital localization of metal atoms is weak,which is more conducive to the transition of electrons from valence band to Fermi level,thereby improving the electron-hole separation efficiency during the thermal decomposition of ammonium perchlorate,promoting the rapid reduction of H atoms and the rapid oxidation of O atoms,better inhibiting the generation of by-products,and the catalytic ability is the strongest.Therefore,Zn O is selected as the best catalyst.（2）The simulation results show that CNTs/Zn O composites have better catalytic performance.The energy band of CNTs/Zn O composites is wider than that of Gra/Zn O composites.The electron transition from the Fermi level of Zn O to the conduction band is stronger,which is conducive to the reduction of hydrogen atoms adsorbed on Zn O by electrons to hydrogen ions.The unidirectional conductivity of CNTs makes electrons flow from Zn O to CNTs,and hydrogen atoms are also reduced in this process.The holes generated after electron transition oxidize the oxygen atoms adsorbed on the surface of carbon nanotubes into superoxide radical anions,promoting the conversion of ammonia to H₂O and NO₂,thereby improving the thermal decomposition efficiency of AP.（3）CNTs/Zn O composites were prepared by liquid phase deposition method.XRD,FT-IR and SEM results showed that Zn O was successfully deposited on the surface of CNTs.4%CNTs/Zn O composites were added to catalyze AP,which reduced the high temperature decomposition peak by 140.23°C.Based on the CNTs/Zn O binary composites,CNTs/Zn O/AP enhanced ternary composite energetic materials were prepared by solvent-nonsolvent method.XRD and FT-IR test results showed that ammonium perchlorate was successfully deposited on the surface of CNTs/Zn O composites.The XRD diffraction peak was consistent with the AP standard peak position,the crystallinity was good,and the complete coating was achieved.SEM test results show that ammonium perchlorate is deposited on the surface of CNTs/Zn O composites.The diameter of the ternary composite energetic material is 40 nm,which belongs to the nano-scale composite energetic material,and no agglomeration occurs.（4）When the mass ratio of CNTs/Zn O/AP reinforced ternary composite energetic material is 1/3/96,the catalytic ability is the strongest,and the high temperature decomposition peak is reduced by 152.94°C,which is 12.71°C earlier than the mixture of CNTs/Zn O and AP with the same ratio,and 14.58°C earlier than pure Zn O.The reasons for the enhanced catalytic ability are as follows:on the one hand,it has the synergistic catalytic effect of CNTs/Zn O binary composites;on the other hand,ammonium perchlorate is a nanomaterial after recrystallization on CNTs/Zn O composites,with increased specific surface area and good uniform dispersion.