Characterization of thermochemical properties of Al nanoparticle and NiO nanowire composites
Thermochemical properties and microstructures of the composite of Al nanoparticles and NiO nanowires were characterized. The nanowires were synthesized using a hydrothermal method and were mixed with these nanoparticles by sonication. Electron microscopic images of these composites showed dispersed NiO nanowires decorated with Al nanoparticles. Thermal analysis suggests the influence of NiO mass ratio was insignificant with regard to the onset temperature of the observed thermite reaction, although energy release values changed dramatically with varying NiO ratios. Reaction products from the fuel-rich composites were found to include elemental Al and Ni, Al2O3, and AlNi. The production of the AlNi phase, confirmed by an ab initio molecular dynamics simulation, was associated with the formation of some metallic liquid spheres from the thermite reaction.
Integrating Al with NiO nano honeycomb to realize an energetic material on silicon substrate
Nano energetic materials offer improved performance in energy release, ignition, and mechanical properties compared to their bulk or micro counterparts. In this study, the authors propose an approach to synthesize an Al/NiO based nano energetic material which is fully compatible with a microsystem. A two-dimensional NiO nano honeycomb is first realized by thermal oxidation of a Ni thin film deposited onto a silicon substrate by thermal evaporation. Then the NiO nano honeycomb is integrated with an Al that is deposited by thermal evaporation to realize an Al/NiO based nano energetic material. This approach has several advantages over previous investigations, such as lower ignition temperature, enhanced interfacial contact area, reduced impurities and Al oxidation, tailored dimensions, and easier integration into a microsystem to realize functional devices. The synthesized Al/NiO based nano energetic material is characterized by scanning electron microscopy, X-ray diffraction, differential thermal analysis, and differential scanning calorimetry.
Development of a low-temperature co-fired ceramic solid propellant microthruster
Low-temperature co-fired ceramic (LTCC) technology has been first successfully employed for the realization of a solid propellant microthruster. The microthruster has potential applications in microspacecraft as an excellent micropropulsion system for high-accuracy station keeping, attitude control, drag compensation and orbit adjust. The design, fabrication and experimental investigation of LTCC microthrusters are reported. Results from experiments on microcombustion, and thrust and impulse measurements both at sea level and in vacuum are presented. Initial tests employing gunpowder-based solid propellant have produced 3.81 × 10−5–1.27 × 10−4 N s of total impulse and 5.55–14.41 s of specific impulse at sea level, and 1.31 × 10−4–2.79 × 10−4 N s of total impulse and 19.05–31.55 s of specific impulse in vacuum. The performance of the LTCC solid propellant microthruster is also compared with that of a silicon-based solid propellant microthruster.