ON THE MECHANISMS OF POROUS SILICON COMBUSTION IN OXYGEN AND AIR ATMOSPHERE WHEN SODIUM PERCHLORATE IS INCORPORATED IN PORES

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.

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.


2021 ◽  
Vol 232 ◽  
pp. 111561
Author(s):  
Rajavasanth Rajasegar ◽  
Yoichi Niki ◽  
Jose Maria García-Oliver ◽  
Zheming Li ◽  
Mark P.B. Musculus

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

1994 ◽  
Vol 358 ◽  
Author(s):  
P. Steiner ◽  
F. Kozlowski ◽  
W. Lang

ABSTRACTIndium, tin, antimony and aluminum are deposited by an electrochemical process into the pores of n-type porous silicon which is anodized with ultraviolet light applied during formation. The presence of these metal atoms in the porous layer is checked by electron microprobe measurement. As reported previously, UV-light etched material shows red photoluminescence (630 nm) and blue electroluminescence (470 nm) without the metal treatment. After metal deposition the photoluminescence intensity decreases slightly (factor 0.5 - 0.8), whereas the spectral position remains constant. The electroluminescence efficiency is significantly enhanced by indium, aluminum and tin in the pores (factor 5 - 90). The tin and antimony treatment causes a red shift to 580 nm and 740 nm, respectively. The conductivity is slightly increased by all kinds of metals by a factor 2-5.


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.


2018 ◽  
Author(s):  
Guangfei Zhu ◽  
Krishna Pattabiraman ◽  
Federico Perini ◽  
Christopher Rutland

2009 ◽  
Vol 151 ◽  
pp. 222-226 ◽  
Author(s):  
Hanna Bandarenka ◽  
Aliaksandr Shapel ◽  
Marco Balucani

Cu-Si nanocomposites formed by an immersion displacement deposition of Cu into porous silicon (PS) matrix have been experimentally studied. SEM and AES were used to investigate the structure and elemental composition of Cu-Si samples. The top part of the Cu-PS samples is shown to demonstrate the following structure: large faceted Cu grains at the top, a porous fine-grained copper film underneath the large grains, and the copper pointed rods extended from the surface into the PS layer. The top part of the silicon skeleton of the PS layer is converted into the copper by the etching followed by Cu displacement deposition. The porosity of the porous layer and displacement deposition times are found to form Cu-Si nanocomposites of various structures and various Cu-Si contents because of various extent of the silicon skeleton transformation into copper.


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