Preparation Of Nanocombustion Catalyst And Its Application In Double-base Propellant

Solid propellant has been widely applied in strategic,tactical missiles,space vehicles,and kinetic energy interceptors as the main energy source of solid rocket motor due to its various advantages,such as high-energy,high-density,and so on.As the main constituent of solid propellants,combustion catalyst can improve the combustion performance efficiently.Compared to the traditional combustion catalyst,metal oxide nanocomposites showed several obvious advantages of high thermal stability and chemical stability,which can increase the burning rate of the solid propellant,reduce the pressure index,and enhance the burning stability.To further study the catalytic mechanism and combustion performance of the metal oxide nanomaterials and nanocomposite metal oxides,we synthesize various metal oxide nanomaterials and metal oxide@graphene oxide nanocomposites,investigate their catalytic performance for the thermal decomposition of the energetic materials in solid propellant,design and optimize different propellant formulations and evaluate the combustion performance,which can provide the foundation for the design of high-performance double base propellant.The main contents covered are as follows:(1)The Fe₂O₃ nanoparticles with different shape and size were successfully synthesized by one-step hydrothermal method,and their structures and morphologies were characterized using SEM.The Fe₂O₃ nanoparticles with height of 64 nm,86 nm and 278 nm are marked as Fe₂O₃-1,Fe₂O₃-2,and Fe₂O₃-3 respectively.The catalytic performance for the thermal decomposition of AP and RDX of the Fe₂O₃ nanoparticles was studied by DSC.The obtained catalytic performance was ranked as Fe₂O₃-1>Fe₂O₃-2>Fe₂O₃-3.These results showed that Fe₂O₃-1 had the higher catalytic performance than that of others,indicating that the smaller particle with the larger specific surface area can obtain the high catalytic ability.Finally,the thermal decomposition kinetic equations of Fe₂O₃-1/RDX,Fe₂O₃-2/RDX and Fe₂O₃-3/RDX are studied,the results show that the Fe₂O₃-1 can reduce the activation energy of the AP and RDX.(2)XRD,SEM and other characterization methods were used to characterize micron-scale B powder(1#),nano-scale B powder(2#),Al powder(3#)and B/Al composite powder(4#).The catalytic decomposition of high-energy oxidant components HMX and CL-20 using nano-scale B powder and B/Al composite powder under different atmospheres(air and nitrogen atmosphere)was studied by DSC and the thermal decomposition kinetics.The results indicate that the nano-scale B power show the strong catalytic decomposition effects for CL-20,while the Al power show the inactivation for the CL-20.The activation entropy?S^?,activation enthalpy?H^?,and activation free energy?G^?thermodynamic function values at the peak temperature of thermal decomposition were studied for catalytic decomposition of the HMX using the B/Al composite powder.(3)CuFe₂O₄-GO nanocomposite was synthesized by in-situ growth method,and the composition structure and morphology of the CuFe₂O₄-GO nanocomposite were characterized and analyzed by XRD,SEM,TEM,FT-IR and XPS.The thermal decomposition catalytic performance of CuFe₂O₄-GO,CuFe₂O₄/GO,CuFe₂O₄ and GO combustion catalyst for RDX was investigated,and the CuFe₂O₄-GO and CuFe₂O₄/GO show a better catalytic performance than that of CuFe₂O₄ and GO.The catalytic performance of the CuFe₂O₄-GO and self-assembled CuFe₂O₄/GO composite combustion catalysts shows no significant difference,which can be attributed to the"positive synergistic effect"between the CuFe₂O₄ particles and GO.(4)Five graphene-tungstate composites were prepared by one-step solvothermal method,and their composition,morphology and structure were systematically characterized by XRD,SEM,TEM,FT-IR,Raman spectroscopy,etc.In addition,the catalytic effect of the as-prepared graphene-tungstate composite for thermal decomposition of energetic compounds RDX,TKX-50 and FOX-7 was studied by DSC method.The results indicate that the as-prepared graphene-tungstate composite show the good compatibility for the RDX and FOX-7.The Mn WO₄-GO and PbWO₄-GO show the significant reduction of thermal decomposition peak temperature of RDX and FOX-7,and the apparent activation energy of RDX and FOX-7 can be reduced.In addition,Fe WO₄-GO show the excellent catalytic activity for the thermal decomposition of TKX-50,which lowers the low temperature and high temperature decomposition peak temperatures of TKX-50 by 20.2 and 27.0°C,respectively.The apparent activation energy of high temperature decomposition decreases72.3 k J·mol^-1,indicating the Fe WO₄-GO can be used as a combustion catalyst containing TKX-50 solid propellant.(5)Based on the study of catalytic decomposition,the double-base and modified double-base propellants were designed using metal composite oxide-GO composite as catalyst.The single-magnification color photography method,high-temperature thermocouple method SEM were used to characterize the high-pressure flame structure,combustion wave temperature distribution and surface morphology of extinguished propellant of double-base and modified double-base propellants containing different catalysts.The results indicate that the PbWO₄-GO show the higher catalytic performance for double-base propellant than that of CuFe₂O₄-GO,and the PbWO₄-GO show the higher catalytic performance for modified double-base propellants than that of Bi₂WO₆-GO.