Preparation And Reaction Properties Of CuO-based Micro-Nano Structured Composite Energetic Materials

As is a kind of composite energetic material,thermite plays an important role in defense industry and economic construction due to its high energy density,oxygen carrying capacity and quality density.However,with the fast development and great progress of society,the performance of traditional thermite can–not meet the need of much stricter requirements of practical applications due to its high onset temperature,poor exothermic performance and slow combustion rate.Therefore,exploring new thermites with excellent reaction performance has become a hot topic in the field of energetic materials.Usually,micro?nano sized fuel and oxidizers can effectively shorten the mass transfer distance between components and significantly improve their exothermic and combustion performance,which can greatly improve the reaction performance of thermite composite energetic materials.In this work,three kinds of copper oxide with different morphologies were prepared by liquid?phase reduction,subsequent heat treatment technology and rapid precipitation method,respectively.Then,four kinds of micro?nano structural composite energetic materials with excellent reaction performance were synthesized by electrophoretic deposition technology and self?assembly technology.Furthermore,the kinetic behavior of composite energetic materials prepared by electrophoretic deposition and the feasibility and preparation conditions of core?shell thermite prepared by self?assembly technology were carefully studied.In addition,the exothermic properties of these composite energetic materials were also investigated in detail.This work provides a novel strategy and method for the development and application of micro?nano structured composite energetic materials.The main research contents and conclusion of the study are as follows:(1)Aiming at the present problem that the electrodeposition kinetics of composite energetic materials are not yet clear,the electrophoretic deposition process of Al/CuO microboxes composite energetic materials has been explored.The Al/CuO microboxes composite energetic materials were fabricated using electrophoretic deposition technology,and the electrophoretic deposition kinetics of Al/CuO microboxes was verified by diffusion control.The CuO microboxes with a particle length of?2?m are adopted as oxidizers for composite energetic materials.The results show that 10%dwb(dry weight of total solids basis)polyethyleneimine can greatly promote the electrophoretic deposition of CuO microboxes on the Ti cathode.Moreover,a good linear relationship was found between the equivalent ratio(?_d)of Al/CuO microboxes composite energetic materials deposited on Ti sheets and the equivalent ratio(?_s)of Al/CuO in suspension,which can be precisely adjusted by tuning the electrophoretic deposition parameters.When the?_d of Al/CuO microboxes composite energetic material in the suspension is 3.0,the heat release of the sample can reach up to 3049J/g.This work provides a new strategy for the preparation of composite energetic materials using electrophoretic deposition technology.(2)To understand the effect of precursors with different morphologies on the electrophoretic deposition kinetics,the electrophoretic deposition process of Al/CuO microspheres composite energetic materials was further studied.The CuO microspheres with a particle length of 100?120nm were successfully synthesized by a simple solution route and subsequent heat treatment and used as oxidizer for composite energetic materials.The Al/CuO microspheres composite energetic materials were prepared by electrophoretic deposition method.It was found that the electrophoretic deposition kinetics of Al/CuO microspheres was controlled by diffusion control.The results show that?_d is linear with?_s,and the equivalent ratio of composite energetic materials(?_d)can be precisely adjusted by changing the electrophoretic deposition parameters.When the equivalent ratio of Al/CuO microspheres composite energetic materials in suspension is 1.5,the heat release of the sample can reach 1977J/g.(3)The core?shell CuO@Al composite energetic materials were prepared through self?assembly technique in response to the problems of long time and complicated procedures needed in the preparation process of composite energetic materials.The CuO microspheres with a particle length of?450nm are successfully synthesized by a simple solution route and subsequent heat treatment.The CuO microspheres were modified with poly(4?vinylpyridine)(P4VP).The surface of CuO microspheres was coated with Al nanoparticles by self?assembly method.The core?shell CuO@Al composite energetic material with CuO microspheres as the core and Al nanoparticles as the coating layer was successfully prepared.DSC results show that when the equivalence ratio?=1.5,the total heat release of core?shell CuO@Al composite energetic material can reach 1860J/g.The sample exhibited good exothermic properties due to the close contact between the fuel and the oxidizer.This work provides a facile strategy for the preparation of core?shell CuO@Al composite energetic materials with high exothermic properties.(4)The reaction between nano?aluminum and oxygen or water vapor in the environment leads to the formation of passivation layer of Al₂O₃,which weakens the exothermic properties of energetic materials.In contrast,Si shows a higher oxidation resistance,which is more stable in long?term storage or transportation,and promising as a new type of fuel for energetic materials.In this context,core?shell Si@CuO composite energetic materials were synthesized through self?assembly technique.The CuO particles with a diameter of?8nm are successfully synthesized by rapid precipitation method.The nano Si was modified by poly(4?vinylpyridine)(P4VP),and nano CuO particles were coated on the surface of nano Si by self?assembly method.The core?shell Si@CuO composite energetic material with Si as core and CuO particles as the coating layer was successfully prepared.DSC results show that the maximum heat release of core?shell Si@CuO composite energetic material can reach 1061.4J/g when the equivalence ratio?=1.0.The short distance of mass transfer between nano Si and CuO enhances the exothermic properties of composite energetic materials,which provides a new strategy for the preparation of Si?based composite energetic materials with outstanding exothermic properties.