Preparation Of Hollow Spherical Nickel Oxide And Its Application In Nanothermite

Nanothermites have attracted wide attention due to their high energy density,short ignition delay time and self-sustained exothermic reaction.This dissertation intends to study the preparation of spherical nano-NiO,explore the control method of the sphere particle size and the number of shell layers of hollow spherical nickel oxide,and study the performance of Al/NiO nanothermite,and investigate the structure of influence of combustion performance,such as pressure generated by combustion.The details are as follows:First,solid NiO was prepared by the oil bath method,and Al/NiO was prepared by the ultrasonic mixing method.The morphology and structure were characterized,and its performance was tested by thermal analysis,ignition,and combustion tests.The results show that the Al/NiO nanothermite with a stoichiometric ratio of 1.8 shows the smallest activation energy,the shortest ignition delay time,the strongest light intensity and the highest peak pressure,showing the highest energy output and the largest combustion performance.This indicates that as the stoichiometric ratio increases,the ignition and combustion performance improves.Secondly,in order to further improve the ignition and combustion performance,a double-layer NiO hollow sphere with a controllable particle size was prepared using a carbon sphere template as an oxidant in nanothermite,and the process of forming a double-layer NiO was described.The results show that as the particle size of NiO hollow spheres decreases,the activation energy of nanoaluminum heating agents decreases,the amount of heat released increases,the light intensity increases,the ignition delay time is shortened,and the boost rate is fast.It is concluded from the light signal peak that the combustion process is mainly affected by the mass diffusion distance,which depends on the gap between the core of the NiO hollow sphere and the shell.Finally,in order to investigate the effect of the number of layers on the combustion performance,a multilayered NiO hollow sphere was prepared using a carbon sphere template to enhance electrostatic adsorption,and was used as an oxidant in nanothermite.The results show that as the number of NiO shell layers increases,the activation energy of nanothermite decreases,the amount of heat released increases,the light intensity increases,the ignition delay time is shortened,and the boost rate is fast.Al/NiO nanothermite have excellent ignition and combustion properties,which is very beneficial for practical applications of micro-electromechanical systems(MEMS).