The Assembly And Application Of Highly Active Nano-aluminum Microsphere Particles

Nano aluminum powder is used in propellants and aluminum-water hydrogen production due to its advantages of high energy density,high heat release,low cost,and wide sources.Adding a certain amount of nano aluminum powder to the propellant can significantly increase the combustion rate and specific impulse.The high activity of nano-aluminum powder lead to the oxidation of nano-aluminum powder and the formation of the dense oxide layer on the surface,resulting in a decrease in active aluminum content.The thickness of the oxide layer limits the further increase of the burning rate in the propellant and also increases the induction time of the reaction in the aluminum-water hydrogen production process.Therefore,for the purpose of maintain the high activity of the nano aluminum powder(n-Al),the surface of the n-Al needs to be coated with modifier.In this paper,polyethylene glycol(PEG)and FC surfactant are used to coat nano aluminum powder.Polyethylene glycol is coated by low-temperature sedimentation method,and FC surfactant is prepared by physical mixing method.The coating mechanism of PEG/n-Al composite particles and FC/n-Al composite particles was analyzed by morphological structure characterization and other characterization methods,and the PEG/n-Al composite particles were evaluated.The possibility of n-Al composite particles and FC/n-Al composite particles used in propellants and aluminum-water hydrogen production.The specific research content is as follows:(1)PEG/n-Al composite particles are prepared by low-temperature recrystallization and deposition.The PEG crystals use n-Al as the nucleus to crystallize on the surface of n-Al.The crystal thickness is about 4-5 nm.Increasing,the crystal thickness of PEG will not increase accordingly.When the PEG concentration is PA6,all the PEG in the solution just completely crystallizes on the n-Al surface.When the PEG concentration is greater than PA6,PEG will crystallize separately in the solution in addition to the crystallized n-Al surface.(2)The F-C/n-Al composite particles are prepared by a physical mixing method,and the thickness of the F-C surfactant coating layer of the composite particles increases as the content of the coating agent increases.Increasing the concentration of F-C surfactant will increase the thickness of the coating layer.Thermal analysis results show that the heat release of F-C/n-Al composite particles is greater than that of PEG/n-Al composite particles.(3)Evaluate the application potential of the prepared PEG/n-Al composite particles and F-C/n-Al composite particles in propellants through the combustion performance,compatibility test and aging test test.The experimental results show that,compared with pure n-Al,both PEG/n-Al composite particles and FC/n-Al composite particles have better combustion performance,and PEG/n-Al composite particles have a shorter ignition delay time.FC/n-Al composite particles have a higher burning rate;both have better stability,and the active content of PEG/n-Al composite particles is only reduced by 1.02% when stored under environmental conditions for 60 days.(4)Test the potential of PEG/n-Al composite particles in aluminum-water hydrogen production through hydrogen production and hydrogen production rate.The experimental results show that the PEG/n-Al composite particles have a considerable hydrogen production rate compared with the pure n-Al after air passivation,but the hydrogen production of PEG/n-Al composite particles is greater than the pure n-Al after air passivation.In summary,PEG/n-Al composite particles and FC/n-Al composite particles can better avoid the oxidation of n-Al and maintain the high activity of n-Al.When the two particles are used in propellants At the same time,FC/n-Al composite particles have better combustion performance.