Nanoenergetic materials are the key to great advances in microscale energy-demanding systems as actuation part, igniter, propulsion unit, and power. An important challenge of energetic materials for microelectromechanical system (MEMS) is the compatibility of standard microsystem techniques with technology process employed in preparing energetic materials producing a large amount of gas and heat. Picric acid is known to react with metals to form highly unstable metallic picrate, which are often employed as explosive materials. In this study, films of zinc picrate were successfully produced with an 'in-situ chemical reaction' method by introducing picric acid onto a ZnO nanowire array, which is fully compatible with technology for MEMS. The films were characterized by nuclear magnetic resonance, X-ray diffraction, XPS, and SEM. The results demonstrate that picric acid reacted with ZnO to form zinc picrate thin film. Differential scanning calorimetry and thermogravimetric analysis measurements show that zinc picrate/ZnO films exhibit producing a large amount of gas, high energy output and lower ignition temperature, which will enhance the diversity of functions on MEMS devices. Therefore, this will open the door to integrate this traditional organic energetic material into microsystem, leading to new generation of MEMS devices. Copyright
In order to study the ignition process and response characteristics of cast polymer-bonded explosives (PBX) under the action of friction, HMX-based cast PBX explosives were used to carry out friction ignition experiments at a 90° swing angle and obtain the critical ignition loading pressure was 3.7 MPa. Combined with the morphology characterization results of HMX-based cast PBX, the friction temperature rise process was numerically simulated at the macro and micro scale, and the ignition characteristics were judged. The accuracy of the numerical simulation results was ensured based on the experiment. Based on the thermal–mechanical coupling algorithm, the mechanical–thermal response of HMX-based cast PBX tablet under friction was analyzed from the macro scale. The results show that the maximum temperature rise is 55 °C, and the temperature rise of the whole tablet is not enough to ignite the explosive. Based on the random circle and morphology characterization results of tablet, the mesoscopic model of HMX-based cast PBX was constructed, and the microcrack friction formed after interface debonding was introduced into the model. The temperature rise process at the micro scale shows that HMX crystal particles can be ignited at a temperature of 619 K under 4 MPa hydraulic pressure loaded by friction sensitivity instrument. The main reason for friction ignition of HMX-based cast PBX is the friction hot spot generated by microcracks formed after interface damage of the tablet mesoscopic model, and the external friction heat between cast PBX tablet and sliding column has little effect on ignition. External friction affects the ignition of HMX-based cast PBX by influencing the formation of internal cracks and the stress at microcracks.
Recently micro-energetic devices by integrating the energetic materials into micro-electromechanical systems (MEMS) to meet the requirements of energy and function diversity have attracted attention from many researchers. Here the technology of modified electrochemical corrosion which is fully compatible with standard microelectronic manufacturing is reported and used to prepare the porous silicon array with a high area ratio. The micro-energetic device was realized by integrating the energetic material lead picrates into the microchannel of porous silicon array. The structure and properties of porous silicon array/lead picrates were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. The results obtained from these analysis demonstrated that the energetic materials lead picrates is integrated into microchannel of porous silicon array successfully and the heat from DSC equal to 796.05J/g suggests that thermal decomposition of lead picrates inside the microchannel of porous silicon array takes place, indicating the micro-energetic device in this paper posses the function of producing gas. Meanwhile, the micro-energetic device exhibits lower ignition temperature compared to other energetic devices. Therefore, this will enhance energy performances and the function diversity for MEMS devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.