Research On Characteristics And Regularity Of Energy Release Of Porous Silicon Nano-energetic Chips

A novel nano-energetic material formed by embedding oxidant in porous silicon (PS). It’s fit for energetic chip because its preparation technology is compatible with MEMS technology. This nano-energetic material has been used in ignition device. But the fundamental research is still very weak and the knowledge of energy control and release is poor. In this dissertation, the material preparation, the chip packaging and the output characteristics and regularity were researched.The main research results are as follows:PS film was prepared by electrochemical etching. The thickness of films increased depending on the increasing of current and conduction time. Films prepared in the current of 0.1 A for 15min were smooth, and the average roughness was only2.7nm while the thickness was 25μm. PS nano-energetic chips (PS nECs) were fabricated in MEMS technologies. From the analysis of X-ray diffraction, the experiment results showed that sodium perchlorate filled in the pores was in the status of sodium perchlorate monohydrate and the presence of Si-O-H in the surface of PS was confirmed. Results of thermoanalysisproved that sodium perchloratemelted before the reaction of the PS nano-energetic materials (PS nEMs).The heat output was 689.5J·g-1.A high speed camera was used to record the reaction process of PS nECs. The duration time was in the grade of millisecond. The reaction delay time was in microsecond studied by an optical fiber. This suggested that PS had an advantage of ignition reliability and duration time. A micro-closed bomb was designed and fabricated to investigate the output pressure. The histories of pressures generated in the micro-closed bomb ranged from 0.22 MPa to 17.99 MPa depending on the increase of the ignition voltages from 80V to 200V.The impulses of reactions tested by the thrust stand were in the grade of μN·s.The results showed that PS nECs were expected to be used in the field of micro-thruster.In order to research the performance of reactions with restrict,a circular nozzle and a convergent-divergent nozzle were designed and fabricated. The results showed that circular nozzle made little contribution to the increase of the impulse. So did the convergent-divergent nozzle in low ignition voltages. While in high ignition voltages, the impulses increased to a great extent with the convergent-divergent nozzle. It reached nearly 2mN·s at 200V while it was 914.52μN·s with a circular nozzle and 728.42μN·s without nozzle.