FAST COMBUSTION MODES OF COMPOSITES "MOUND OF POROUS SILICON FRAGMENTS-SODIUM PERCHLORATE MONOHYDRATE" IN THE ATMOSPHERE

Author(s):  
V. N. MIRONOV ◽  
◽  
O. G. PENYAZKOV ◽  
E. S. GOLOMAKO ◽  
S. O. SHUMLYAEV ◽  
...  

Numerous studies have demonstrated the potential use of porous silicon (pSi) as an energetic material. However, there are a number of dificulties in such an application of nanostructured silicon. Here are two of the most serious dificulties.

Author(s):  
V. N. MIRONOV ◽  
◽  
O. G. PENYAZKOV ◽  
E. S. GOLOMAKO ◽  
S. O. SHUMLYAEV ◽  
...  

Currently, various groups of scientists are investigating the possibility of using nanostructured porous silicon as promising solid fuels (or additives to composite solid fuels) and as miniature energy sources for microelectromechanical systems. The results presented in the paper demonstrate the prospects of the proposed novations aimed at increasing the efficiency of nanoporous silicon as an energetic material. They are based on the use of mounds of porous silicon fragments treated with sodium perchlorate solutions and dried under low warming (MPSF-composites) as energy composites. For example, when the weights of the MPSF-composites and the porous layer composites on monocrystal substrates treated with sodium perchlorate solutions (PS-composites) are close to each other, the overpressure at the front of the shock waves developing at the initiation and propagation of combustion in the case of MPSF-composites is 5-6 times higher.


2015 ◽  
Vol 1758 ◽  
Author(s):  
Nicholas W. Piekiel ◽  
Christopher J. Morris ◽  
Wayne A. Churaman ◽  
David M. Lunking

ABSTRACTThe present study explores the burning of microscale porous silicon channels with sodium perchlorate. These on-chip porous silicon energetics were embedded in crystalline silicon, and therefore surrounded on three sides by an efficient thermal conductor. For slow burning systems, this presents complications as heat loss to the crystalline silicon substrate can result in inconsistent burning or flame extinction. We investigated <100 μm wide porous silicon strips, sparsely filled with sodium perchlorate (NaClO4), to probe the limits of on-chip combustion. Four different etch times were attempted to decrease the dimensions of the porous silicon strips. The smallest size achieved was 12 x 64 µm, and despite the small dimensions, demonstrated the same flame speed as the larger porous silicon strips of 6-7 m/s. We predict that unreacted porous silicon acts as a thermal insulator to aid combustion for slow burning porous silicon channels, and SEM images provide evidence to support this. We also investigated the small scale combustion of a rapidly burning sample (∼1200 m/s). Despite the rapid flame speed, the propagation followed a designed, winding flame path. The use of these small scale porous silicon samples could significantly reduce the energetic material footprint for future microscale applications.


2021 ◽  
Vol 14 (2) ◽  
pp. 83-91
Author(s):  
V.N. MIRONOV ◽  
◽  
O.G. PENYAZKOV ◽  
E.S. GOLOMAKO ◽  
S.O. SHUMLYAEV ◽  
...  

One of the criteria for the development of high-energy processes is the large specific surface area of the solid component of composites. Therefore, the maximum preservation of its nanostructured skeleton when separating the porous layer from the monocrystal substrate is relevant. Based on the analysis of the quality of the porous layer under various methods and modes of its formation, two methods were selected that provide simple and effective separation of the porous structure from the monocrystal. For composites based on mounds of porous silicon (pSi) fragments (MPSF), three series of experiments were carried out with fragments of porous layers of different age (formed within the previously established time limits before composites creation) with registration of combustion dynamics, temperatures and combustion spectra, as well as intensity of disturbances in the atmosphere forming during combustion of MPSF-composites. Four combustion modes of MPSF-composites were established: smoldering, frontal, aerosol, and frontal-aerosol. The ignition induction times were determined: from 1 to 50 ^s, pressure pulses in the atmosphere at a distance of 260 mm from the ignition site - up to 1.6 bar (with a mass of composites up to 0.4 g). Combustion velocities ofMPSF-composites and their dependences onthe coefficient of stoichiometry and humidity of sodium perchlorate monohydrate are established.


2015 ◽  
Vol 1758 ◽  
Author(s):  
Ani Abraham ◽  
Nicholas W. Piekiel ◽  
Cory R. Knick ◽  
Christopher J. Morris ◽  
Edward Dreizin

ABSTRACTWe present the first quantitative assessment of combustion dynamics of on-chip porous silicon (PS) energetic material using sulfur and nitrate-based oxidizers with potential for improved moisture stability and/or minimized environmental impact compared to sodium perchlorate (NaClO4). Material properties of the PS films were characterized using gas adsorption porosimetry, and profilometry to calculate specific surface area, porosity and etch depth. The PS/sulfur energetic composite was formed using three pore loading techniques, where the combustion speeds ranged from 2.9 – 290 m/s. The nitrate-based oxidizers were solution-deposited using different compatible solvents, and depending on the metal-nitrate yielded combustion speeds of 3.1 – 21 m/s. Additionally, the combustion enthalpies from bomb calorimetry experiments are reported for the alternative PS/oxidizer systems in both nitrogen and oxygen environments.


Author(s):  
V. N. MIRONOV ◽  
◽  
O. G. PENYAZKOV ◽  
P. N. KRIVOSHEYEV ◽  
I. A. IVANOV ◽  
...  

The processes of pSi ignition and combustion in oxygen are described. When spark ignition in the porous layer releases the Joule heat, it leads to a significant heating-up of the breakdown region.


2010 ◽  
Vol 2 (11) ◽  
pp. 2998-3003 ◽  
Author(s):  
Collin R. Becker ◽  
Luke J. Currano ◽  
Wayne A. Churaman ◽  
Conrad R. Stoldt

2017 ◽  
Vol 231 (9) ◽  
Author(s):  
Sangeetha Periasamy ◽  
Sasirekha Venkidusamy ◽  
Ragavendran Venkatesan ◽  
Jeyanthinath Mayandi ◽  
Joshua Pearce ◽  
...  

Abstract:The size effect of nanoscale silicon in both amorphous and porous silicon was investigated with micro-Raman spectroscopy. Silicon nanostructures in amorphous silicon were deposited on quartz substrates by plasma enhanced chemical vapor deposition (PECVD) with deposition powers of 15, 30 and 50 W. Micro-Raman spectra of the nanostructured silicon show the T


Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 119 ◽  
Author(s):  
Nikola Baran ◽  
Hrvoje Gebavi ◽  
Lara Mikac ◽  
Davor Ristić ◽  
Marijan Gotić ◽  
...  

Porous silicon has been intensely studied for the past several decades and its applications were found in photovoltaics, biomedicine, and sensors. An important aspect for sensing devices is their long–term stability. One of the more prominent changes that occur with porous silicon as it is exposed to atmosphere is oxidation. In this work we study the influence of oxidation on the sensing properties of porous silicon. Porous silicon layers were prepared by electrochemical etching and oxidized in a tube furnace. We observed that electrical resistance of oxidized samples rises in response to the increasing ambient concentration of organic vapours and ammonia gas. Furthermore, we note the sensitivity is dependent on the oxygen treatment of the porous layer. This indicates that porous silicon has a potential use in sensing of organic vapours and ammonia gas when covered with an oxide layer.


2014 ◽  
Vol 118 (20) ◽  
pp. 10893-10902 ◽  
Author(s):  
Shahana Chatterjee ◽  
Rachel Carter ◽  
Landon Oakes ◽  
William R. Erwin ◽  
Rizia Bardhan ◽  
...  

2003 ◽  
Vol 797 ◽  
Author(s):  
J. Diener ◽  
N. Künzner ◽  
E. Gross ◽  
D. Kovalev ◽  
M. Fujii

ABSTRACTAnisotropic nanostructuring of bulk silicon (Si) leads to a significant optical anisotropy of single porous silicon (PSi) layers. A variation of the etching current in time allows a controlled modification of the porosity along the growth direction and therefore a three-dimensional variation of the refractive index (in plane an in depth). This technique can be important for photonic applications since it is the basis of a development of a variety of novel, polarization sensitive, silicon-based optical devices: retarders, dichroic Bragg Reflectors, dichroic microcavities and Si based polarizers.


Sign in / Sign up

Export Citation Format

Share Document