scholarly journals Nanostructured Energetic Materials with Sol-gel Methods

2003 ◽  
Vol 800 ◽  
Author(s):  
Alexander E. Gash ◽  
Joe H. Satcher ◽  
Randall L. Simpson ◽  
Brady J. Clapsaddle

AbstractThe utilization of sol-gel chemical methodology to prepare nanostructured energetic materials as well as the concepts of nanoenergetics is described. The preparation and characterization of two totally different compositions is detailed. In one example, nanostructured aerogel and xerogel composites of sol-gel iron (III) oxide and ultra fine grained aluminum (UFG Al) are prepared, characterized, and compared to a conventional micron-sized Fe2O3/Al thermite. The exquisite degree of mixing and intimate nanostructuring of this material is illustrated using transmission and scanning electron microscopies (TEM and SEM). The nanocomposite material has markedly different energy release (burn rate) and thermal properties compared to the conventional composite, results of which will be discussed. Small-scale safety characterization was performed on the nanostructured thermite. The second nanostructured energetic material consists of a nanostructured hydrocarbon resin fuel network with fine ammonium perchlorate (NH4ClO4) oxidizer present.

2011 ◽  
Vol 217-218 ◽  
pp. 169-174
Author(s):  
Lin Xin Tong ◽  
Jin Hong Li ◽  
Jian Cao

. A series of gels with 3Al2O3•2SiO2 were prepared by Sol-gel method and heated at several temperatures for 2 h to synthesize Ti, Fe-doped mullite. The received powers with highest amount of TiO2 and Fe2O3 additive in range of 3.7-5.6 % and 12.5-15.9 % respectively as starting materials were characterized using X-ray powder diffraction (XRD), scanning electron microscopies (SEM) and energy dispersive spectrometry(EDX). Fe3+ and Ti4+ cation has been incorprated into the crystal lattice of mullite unevenly. The overall trend of Ti, Fe-doped mullite powers with additive amount changing is Δa>Δb>Δc(Except sample 5.6Ti-1350 is Δb>Δa>Δc owing to its excess amount of TiO2), and the relative change of Ti, Fe-doped mullite powers is Δc(%)>Δb(%)>Δa(%)(Except sample 5.6Ti-1350 and 15.9Fe-1350 is Δb(%)>Δc(%)>Δa(%) with the maximum amount of dopant ions).


2003 ◽  
Vol 800 ◽  
Author(s):  
Thomas B. Brill ◽  
Bryce C. Tappan ◽  
Jun Li

ABSTRACTThe objective of this work is to try to create new behaviors of energetic materials by using sol-gel processing and freeze drying to incorporate the energetic material into the fuel matrix at the nano particle size scale. Hydrazinium diperchlorate ([N2H6][ClO4]2) and resorcinol-formaldehyde were chosen in one example, and CL-20 and nitrocellulose were chosen in another. High solids loadings were achieved by the cryogel method. Characterization was carried out by elemental analysis, SEM, TEM, AFM, T-jump/FTIR spectroscopy, DSC, and drop-weight impact testing. The nanoscale formulations do indeed exhibit several different behaviors, such as enhanced burning characteristics and unusual morphologies, and appear to be a promising direction to pursue.


2003 ◽  
Vol 800 ◽  
Author(s):  
Brady J. Clapsaddle ◽  
Lihua Zhao ◽  
Alex E. Gash ◽  
Joe H. Satcher ◽  
Kenneth J. Shea ◽  
...  

ABSTRACTIn the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology, affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Furthermore, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. As a result, the desired organic functionality is well dispersed throughout the composite material on the nanoscale. By introducing a fuel metal into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due to the expected increase of mass transport rates between the reactants. The synthesis and characterization of these metal oxide/silicon oxide nanocomposites and their performance as energetic materials will be discussed.


2012 ◽  
Vol 626 ◽  
pp. 425-429 ◽  
Author(s):  
N.N. Hafizah ◽  
Mohamed Zahidi Musa ◽  
Mohamad Hafiz Mamat ◽  
M. Rusop

In this study, TiO2nanopowder was synthesized via a sol-gel grinding method. The effects of TiO2precursor concentration of TiO2nanopowder were investigated. The TiO2nanopowder obtained were characterized using X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM) for their structural properties. From the calculation of the crystallite size in XRD, the size of the nanoparticles obtained is 49.55 nm at the highest TiO2precursor concentration. In contrast, at the lower concentration of 0.4 molar give the cryatallite size of 12.84 nm. Further, XRD and Raman spectrum results confirmed the TiO2nanopowder obtain composed of only anatase phase. The FESEM micrographs of TiO2nanopowder also were discussed in this paper.


2012 ◽  
Vol 488-489 ◽  
pp. 506-510 ◽  
Author(s):  
Sikander Rafiq ◽  
Zakaria Man ◽  
Abdulhalim Maulud ◽  
Nawshad Muhammad ◽  
Saikat Maitra

Composite membranes were prepared by incorporating inorganic silica nanoparticles into blends of polysulfone/polyimide (PSF/PI) membranes via sol-gel route. Morphological structures of the developed membranes were carried out by scanning electron microscopy (SEM). Spectroscopic analysis of the hybrid membranes were done by fourier transform infrared spectroscopy (FTIR) analysis. Differential scanning calorimetry (DSC) analysis shows that the glass transition temperature (Tg) increased from 209oC to 238oC in the hybrid membranes followed by thermogravimetric analysis (TGA) that showed significant improvement in thermal stability of the developed membranes.


2016 ◽  
Vol 851 ◽  
pp. 61-65 ◽  
Author(s):  
Kun Li Cao ◽  
Yan Wu ◽  
Jun Wang ◽  
Xiao Yu Hui ◽  
Xiao Tang Wang

Cellulose is a kind of renewable biological template with complex microstructure. Surface sol-gel technology, a practical and environmental-friendly approach to produce silica nanotubes, was discussed in this paper. A series of characterization techniques, namely thermal field emission scanning electron microscopy (SEM), and Aztec X-act spectrometer were used to characterize these samples. The design of the nanotube structure was achieved by natural cellulose and cellulose nanocrystals (CNC), and this nanocopying methodology provided silica nanotubes of cellulose template in nanometer precision.


2011 ◽  
Vol 284-286 ◽  
pp. 597-600
Author(s):  
Dai Mei Chen ◽  
Hai Peng Ji ◽  
Jian Xin Wang ◽  
Jian Chen ◽  
Xin Long Luan ◽  
...  

Nitrogen doped TiO2/sepiolite composite materials (N-TiO2/sep) with different nitrogen contents were prepared by a sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), respectively. XRD and SEM results showed that anatase-TiO2nanoparticles were distributed homogenously on the surface of sepiolite. XPS revealed that N atoms could incorporate into the lattice of anatase TiO2substituting the oxygen atoms sites of oxygen atoms.


2007 ◽  
Vol 997 ◽  
Author(s):  
Ashish Garg ◽  
Soumya Kar ◽  
Anju Dixit ◽  
D C Agrawal

AbstractIn this work, we report on the synthesis and characterization of thin films of (BiFeO3)1−x (PbTiO3)x (BFPT) solid solutions of compositions around morphotropic phase boundary (MPB) grown on platinized silicon (111) Pt/TiO2/SiO2/Si substrate by sol-gel based spin coating technique. The films were post-annealed at 700 and 750°C for 1 h in air. Morphological analysis of the films was carried out by scanning electron microscopy. Grazing incidence X-ray diffractometry revealed the perovskite structure of the films and peaks suggested the presence of rhombohedral structured pure BFPT phase in polycrystalline form. Scanning electron microscopy suggested that films annealed at 750degC had a denser microstructure as compared to those at 700°C. The room temperature dielectric constant of the films with composition of BF:PT :: 75:25 was measured to be ∼1200 at a frequency of 100 kHz.


2014 ◽  
Vol 775-776 ◽  
pp. 97-101
Author(s):  
Loanda Raquel Cumba ◽  
U.O. Bicalho ◽  
D.R. Carmo

This paper describes the preparation and complementary characterization of a composite formed from the activation of titanium isopropoxide by phosphoric acid and deionized water (TiP).Techniques such as, X-ray diffraction (XRD), Raman , electronic (UV-vis) and Scanning electron microscopies (SEM) were used for characterization of this new composite formed. In the X-ray diffractogram of TIP was observed four intense peaks. A strong absorption was observed in the region 362-445 nm. The scanning electron microscopy of TiP, shows that the prepared material consists mostly of a cluster of spherical particles with diameters ranging from 2.35 to 2.60 μm.


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