Preparation And Properties Of Boron-potassium Nitrate Ignition Powder Doped With Carbon Nanomaterials

Pyrotechnic composition is the basic charge of igiiition devices which are widely used in national defense and aerospace fields.BPN(Boron and Potassium Nitrate)is one of the most well-known ignition composition which both owns safety and high energy.BPN is now able to meet the demands of many kinds of ignition device used in different environment.However,the future scenes of application might be much more severe for BPN ignition composition,with the development of modem military technology.For past decades,researchers have made a comprehensive understanding of the changes of BPN's properties by changing the ratio of boron to potassium nitrate and particle size of the ingredients.However,there is little researches about the counterparts by changing the additions in the ignition composition,and it is fairly simple of the choices on the doping materials and methods.In fact,recent researches demonstrate that the properties of energetic materials will get sharp increase after doping with carbon nanomaterials.Therefore,it is necessary to study the effect of doped carbon nanomaterials on BPN reaction characteristics and ignition perfonnance,so that BPN would fit the more severe environments.This article chosed reduced carbon nanotubes(CNTs)and graphene oxide(rGO)as additions and then prepared the BPN ignition composition doped with CNTs(CNTBPN)and rGO(rGOBPN)respectively.By changing the proportion of carbon nanomaterials,the influence law of types and proportions of carbon nanomaterials on BPN was studied.The results of experiments showed that the comprehensive performances of CNTBPN and rGOBPN including sensitivity,peak pressure,and burning rate,etc.got great increase.The main works are listed as below:1.Through the comparison of characterization,the ice template method was determined to be the doping methods for preparing boron potassium nitrate composites dope with carbon nanomaterials.The CNTBPN and rGOBPN ignition composition were prepared,and the basic properties of the prepared samples were characterized by SEM,IR and Raman spectra,and N2 adsorption/desorption test,which prove that the prepared pure CNTBPN own layered structUre.Then the boron nanoparticles coated with graphite carbon(GBPN)were prepared by high temperature calcined glucose coated boron powder.The SEM,TEM,and EDS characterization results of GBPN prove that this method could effectively reduce the oxygen content and produce a graphite coating on the surface of boron nanoparticles and the as-prepared carbon coating could protect boron particles from oxidization.2.The sensitivity and thermal properties of CNTBPN and rGOBPN were characterized by impact sensitivity,hot bridge-wire,laser ignition threshold tests and TG/DSC.It was found that the mechanical sensitivity and thermal sensitivity of CNTBPN were much better than that of rGOBPN,but their laser sensitivities were similar.The trends of sensitivity value showed that sensitivity decreases with the increase of the proportion of carbon materials which ranged from 1%to 9%.The results of thermal analysis shows that CNTs can effectively reduce the temperature of decomposition reaction of BPN,while rGO slightly raise the initial temperature of the reaction..In addition,the rGO is more deeply involved in the reaction than the CNTs.3.The burning rate of the ignition composition in one-open-end quartz tube was tested and the pressure-time curve of point gunpowder in closed container was measured.The statistical data showed that the burning rate increased first and then decreased with the proportion of carbon increased from I%to 9%(the max burning rate appeared when the proportion of carbon nanomaterials was 5%),while the peak pressure increased monotonically.In addition,the addition of carbon nanomaterials will lead to a small increase in the delay time of laser ignition.The delay time would rise with the increase of the proportion of carbon materials which was between l%to 9%.Through the work of this paper,the mechanical and thermal sensitivity of BPN composition were greatly reduced,and the output pressure was significantly improved by adding carbon nanomaterials by ice template method.And the law of regulating these properties could make it easier for BPN ignition composition to fit more severe application environments.