Study On The Fabrication And Properties Of MEMS Digital Solid Micro Thruster System

With the successive development of micro-nano satellite industry, the micro propulsion system is under urgent demand, and the MEMS digital solid microthruster has become a research hotspot owing to its outstanding advantages. This paper aims at developing and studying on the design, fabrication and testing of10×10matrix digital solid microthruster array, the principle conclusions are as follows:Two types of digital solid microthruster has been designed:the bottom igniting structure and the top igniting structure, and the main research was carried out on the former one. The heat conduction was simulated by ANSYS, hence SiO2/Si substrate and epoxy resin were chosen as ignition layer and chamber. A SOI wafer was used to prepare the cavity and SiO2diaphragm, which can improve the combustion efficiency and increase the specific impulse.A single lead of10x10array was designed and prepared for ignition circuit, the characteristic of ignition has been studied on metal silicide heat resistance film, polysilicon thermal resistance film and polysilicon electric explosive bridge membrane under constant voltage. The results show that the former two are not suitable for MEMS digital solid micro thruster, however, the polysilicon electric explosive bridge membrane can vaporize rapidly and generate lots of plasma under low voltage, which can ensure reliable ignition. A series of electric explosive tests have been carried out on12kinds of polysilicon electric explosive bridge of different resistance, and the5.2Ω one turned out to be the best, the stable excitation voltage of which is16V.The Al/CuO and Al/Bi2O3nanothermites were respectively prepared by sol-gel method and ultrasonic method in order for the charge of micro propulsion array. Through the ignition matching experiments, it was found that:Al/Bi2O3could easily lead to a sympathetic detonation of adjacent units because of the large quantities of heat and gas; While the combustion of Al/CuO propellant was smooth and stable with very short ignition delay time——1.7ms in average, and the success rate is100%.By using inkjet printing technology, the adhesive bonding between the layers has been realized with H70E binder that crisscross the chip.The propulsion performance has been tested on a packaged microthruster array which integrated with Al/CuO nanothermite through a simple pendulum micro impulse measuring system, the measured average impulse was1.863×104N· s and the specific impulse was39.7s.