The Preparation And Catalytic Performance Research Of PbCO₃/CuO Nanocomposite Particles

Lead salt and copper salt?or oxides?are ofen used in the duble base propellant or modified duble base propellant as a kind of combustion catalyst.In order to improve the catalytic effect of combustion catalyst,people usually prepare lead/copper composite particles or synthesize nanoparticles by chemical method.But the dispersed homogeneous degree of catalytic component in mixed system could be undesirable,if various combustion catalysts are blended together,reducing the catalytic effect for propellant.In this paper,we focus on the preparation technology of PbCO₃/CuO nanocomposite particles,and explore its influence on the combustion properties of solid propellant.The details as follows:Firstly,the PbCO₃/CuO nanocomposite particles was prepared by mechanical ball milling method via using the PbCO₃ and CuO as raw material,and the optimum ball milling processing parameter has been discussed.The size distribution was detected by the nano particle analyzer,the particle shape and size were observed by SEM,and the crystal shape,element type and purity of product were analyzed by XRD,and EDS respectively.The dispersed homogeneous degree of the two components was quantitatively analyzed by calculating the standard deviation of PbCO₃ and CuO content independently.The results show that diameter of the PbCO₃/CuO nanocomposite particles is about 70 nm,and the dispersed homogeneous degree of PbCO₃ and CuO reach to 95.40%and 92.60%separately.No impurity was generated and the crystal form of PbCO₃ and CuO was unchanged during the preparation process.Secondly,the influence of PbCO₃/CuO nanocomposite particles on the thermal decomposition of double base binder?NC/NG?and NQ was researched by DSC.Compared to the catalyst with a mixture of raw PbCO₃ and raw CuO,the thermal decomposition peak temperature of NC/NG and NQ that contain PbCO₃/CuO nanocomposite particles reduced by 29.35? and 13.73? respectively,meanwhile,apparent decomposition heat increased by 606J·g-1 and 235J·g-1 separately.In addition,apparent activation energy,activation enthalpy,activation entropy and Gibbs free energy of NC/NG and NQ were estimated.Above all indicates that the PbCO₃/CuO nanocomposite particles have a better catalytic behavior for NC/NG and NQ than a mixture of raw PbCO₃ and CuO.Thirdly,the PbCO₃/CuO nanocomposite particles were applied to the double base propellant and the modified duble base propellant,with the burning rate were tested by using target line method.To a greater extent than a mixture of raw PbCO₃ and raw CuO,the PbCO₃/CuO nanocomposite particles can increase the burning rate of the double base propellant and the modified duble base propellant.When the PbCO₃/CuO nanocomposite particles were used in the NC/NG propellant,the NC/NG/NQ propellant and the NC/NG/HMX/NQ propellant,the combustion pressure index were reduced by 0.080,0.059 and 0.086 respectively,compared to the catalyst with a mixture of raw PbCO₃ and raw CuO.