Showing papers on "Ammonium perchlorate published in 2004"

Effects of Nanometer Ni, Cu, Al and NiCu Powders on the Thermal Decomposition of Ammonium Perchlorate

Abstract: A study of the decomposition behaviour for Ammonium Perchlorate(AP) was carried out by differential thermal analysis and the two decomposition peaks were observed. The high temperature peak was found to shift to lower temperatures, but the corresponding shift in the low temperature peak was smaller due to the effect of nanometer metal powders. Results shows that Cu and NiCu nanopowders decreased both the high and low decomposition temperature, while Ni and Al nanopowders just decreased the high decomposition temperature and increased the low decomposition temperature. Metal micron-sized powders show catalytic effects on the thermal decomposition of AP, but their effects are less than that of nanometer metal powders. With the increase in content, nanometer metal powders enhanced their catalytic effect on the high temperature decomposition of AP, however their effect was weakened on the low temperature decomposition.

Behaviour of ammonium perchlorate-based propellants and a polymer-bonded explosive under impact loading

Abstract: The response of a range of ammonium perchloratebased propellants and a polymerbonded explosive to dropweight impact loading has been studied using highspeed photography. This technique allows the g...

TG studies of a composite solid rocket propellant based on HTPB-binder

Abstract: Thermal decomposition kinetics of solid rocket propellants based on hydroxyl-terminated polybutadiene-HTPB binder was studied by applying the Arrhenius and Flynn-Wall-Ozawa's methods. The thermal decomposition data of the propellant samples were analyzed by thermogravimetric analysis (TG/DTG) at different heating rates in the temperature range of 300-1200 K. TG curves showed that the thermal degradation occurred in three main stages regardless of the plasticizer (DOA) raw material, the partial HTPB/IPDI binder and the total ammonium perchlorate decompositions. The kinetic parameters Ea (activation energy) and A (pre-exponential factor) and the compensation parameter (Sp) were determined. The apparent activation energies obtained from different methods showed a very good agreement.

Intermittent Burning of Ammonium Perchlorate-Hydrocarbon Binder Monomodal Matrixes, Sandwiches, and Propellants

Abstract: The onset of the midpressure extinction of certain formulations (termed matrixes) of ammonium perchlorate (AP) of monomodal particle size distribution and hydroxyl-terminated polybutadiene binder, in the pressure range around 2-5 MPa, is examined. These matrixes, besides being tested in isolation, have been included in between AP laminas to form sandwiches and mixed with coarse AP particles to form high solids-loading (87.5%) non-aluminized propellants. The burning rates of the sandwiches show abnormal trends with pressure such as low or negative exponents in ranges corresponding to the onset of the midpressure extinction of their respective matrixes. The propellants exhibit this behavior to a lesser degree. Quenched surfaces (self-extinguished or intentionally interrupted during burning) of all the three types of samples were analyzed using a scanning electron microscope, and the burning history of the samples was captured with a high-speed digital camera. The results indicate the prevalence of intermittent burning of the matrixes as the pressure is varied across the boundary between continuous burning and self-extinction (burn/no-burn boundary) of the matrixes. The burning surfaces are marked by extreme three dimensionality coupled with a redistribution of the fine AP particles and the binder. The observations are explained based on the combined effects of the need for the AP particles and the binder to accumulate relative to each other on the burning surface depending on the difference in their pyrolysis rates and the existence of the binder in a molten state on the burning surface.

Combustion of Propellants with Ammonium Dinitramide

Abstract: This paper reports a series of experiments involving ammonium dinitramide (ADN), a new energetic oxidizer of potential use in composite solid propellants. The experiments include (a) self-deflagration of pressed pellets of ADN; (b) combustion of sandwiches with ADN laminae on both sides of a binder lamina that is either “pure” or filled with particulate oxidizer and other additives; and, (c) combustion of propellants with a bimodal oxidizer size distribution, wherein, combustion of coarse ADN and fine AP (ammonium perchlorate) and vice versa were used, in addition to mixtures of coarse ADN and AP, fine ADN and AP, and all-ADN or all-AP formulations.

Solid-phase conductive fuels for chemical microactuators

Abstract: In this work, conductive, composite propellant-type, solid fuels are introduced and characterized for use in microactuators. Ignition was achieved with ammonium perchlorate-based fuels by passing electrical current through solid fuel compositions containing 20 vol.% graphite powder. Feasibility of this fuel is also demonstrated with the ignition of preliminary combustors. The fuels tested consist of ammonium nitrate, ammonium perchlorate, or sodium azide as the main fuel component, hydroxyl terminated polybutadiene or glycidyl azide polymer as the binder, various rate modifying additives including magnesium powder and submicron-sized aluminum powder, as well as graphite powder, which enables the fuel to become conductive. The resultant fuel mixture serves to simplify device fabrication by allowing ignition to occur by passing current directly through the fuel sample from two MEMS fabricated electrodes as opposed to relying on the transfer of heat from external or imbedded igniters. Results of burn time and conductivity testing indicate that the addition of approximately 20% graphite by volume enables conventional composite propellants to become conductive. Also, the addition of graphite roughly doubles the overall decomposition time in fuels containing hydroxyl terminated polybutadiene and only slightly increases overall decomposition time in fuels containing glycidyl azide polymer.

Ammonium perchlorate-containing gas generants

Abstract: Ammonium perchlorate-containing gas generant compositions which, upon combustion, produce or result in an improved effluent and related methods for generating an inflation gas for use in an inflatable restraint system are provided. Such ammonium perchlorate-containing gas generant compositions include ammonium perchlorate present with a mean particle size in excess of 100 microns. Such ammonium perchlorate-containing gas generant compositions also include or contain a chlorine scavenger present in an amount effective to result in a gaseous effluent that is substantially free of hydrogen chloride when the gas generant is combusted, wherein at least about 98 weight percent of the chlorine scavenger is a copper-containing compound. Suitable copper-containing chlorine scavenger compounds include basic copper nitrate, cupric oxide, copper diammine dinitrate-ammonium nitrate mixture wherein ammonium nitrate is present in the mixture in a range of about 3 to about 90 weight percent, copper diammine bitetrazole, a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate and combinations thereof.

Ballistic Properties of Mixed Hybrid Propellants

Abstract: The objective of this project is to experimentally characterize the ballistic properties of a mixed-hybrid propulsion concept that is both controllable and safe. The propulsion configuration was a center-perforated grain with gaseous oxidizer injected at the head end. The fuel grains were loaded with low levels of oxidizer and additives that enhanced their density, and increased the solid regression rate. The propellant formulations have been formulated using a design of experiments approach that evaluates the effects of three ingredients. They were evaluated at the University of Alabama in Huntsville Propulsion Test Facility to determine fundamental ballistic properties that are necessary inputs to designers for system evaluations. The results show that the ingredients added to the solid grain produces up to a 150-300% augmentation in the solid burning rate when compared to grains without any additives at the same flux and pressure levels. The burning rate was determined to be both a function of pressure and oxidizer flux. The propellant with the 25% ammonium perchlorate and the additive burned the fastest. The propellants will stop burning when the gaseous oxidizer flow is stopped.

Effects of Metal and Composite Metal Nanopowders on the Thermal Decomposition of Ammonium Perchlorate （AP） and the Ammonium Perchlorate／Hydroxyterminated Polybutadiene （AP／HTPB） Composite Solid Propellant

Abstract: Effects of metal (Ni, Cu, Al) and composite metal (NiB, NiCu, NiCuB) nanopowders on the thermal decomposition of ammonium perchlorate (AP) and composite solid propellant ammonium perchlorate/hydroxyterminated polybutadiene (AP/HTPB) were studied by thermal analysis (DTA). The results show that metal and composite metal nanopowders all have good catalytic effects on the thermal decomposition of AP and AP/HTPB composite solid propellant. The effects of metal nanopowders on the thermal decomposition of AP are less than those of the composite metal nanopowders. The effects of metal and composite metal nanopowders on the thermal decomposition of AP are different from those on the thermal decomposition of the AP/HTPB composite solid propellant.

Studies on Nonaluminized High Burning Rate AP-Composite Propellants

Abstract: This paper discusses the effect of replacement of hydroxyl terminated poly butadiene (HTPB) by butacene on the burning rates of a nonaluminized ammonium perchlorate (AP)–based composite propellant. A remarkable burning rate enhancement (60–100%) was observed on replacement of HTPB by butacene to the extent of 25%. Replacement of 50–75% HTPB by butacene led to further increase in burning rate by merely 10–20%, and no incremental effect was observed on complete replacement of HTPB. Butacene-based propellants also exhibited a lower pressure exponent (n) of the burning rate. The results obtained are in line with the findings of other researchers on aluminized AP composite propellants. Addition of transition metal oxides, ferric oxide (FO), and copper chromite (CC) to butacene-based formulations led to further enhancement of the burning rates, albeit to a less extent than in the case of HTPB-based systems. However, the burning rates of the former were higher than those of the latter in the case of ballisticall...

The Perchlorate Dilemma in Drinking Water

Abstract: Perchlorate (ClO 4 ) is an anion that is very mobile in aqueous systems. It is introduced in the environment from the dissolution of the ammonium, potassium, magnesium, or sodium perchlorate salts. It can persist for many decades under typical groundwater and surface-water conditions, because of its resistance to reaction with other available constituents. A major source of perchlorate contamination is the manufacture of ammonium perchlorate, which is used as the oxidizer component and primary ingredient in solid propellant for rockets, missiles, and fireworks. Other sources of perchlorate contamination include its use in nuclear reactors and electronic tubes; as an additive in lubricating oils, tanning and finishing leather; and as a fixer for fabrics and dyes, in electroplating, in aluminum refining, in rubber manufacture, and in the production of paints and enamels. Chemical fertilizer also has been reported to be a potential source of perchlorate contamination.

Azido Polymers-Energetic Binders for Solid Rocket Propellants

Abstract: High-energy solid rocket propellants are composite materials having a binder [hydroxy terminated polybutadiene (HTPB)], high-energy additives [e.g., ammonium perchlorate (AP)], and pyrolants (metal...

Safety firecracker compound containing perchlorate

Abstract: The invention relates to a perchlorate-containing safe firecracker powder, combined of perchlorate, aluminum powder, sulfur and perlite powder, where the perchlorate is potassium perchlorate, barium perchlorate, ammonium perchlorate, or their optional combination. If adopting a perchlorate, first choose potassium perchlorate. Its formula is simple, its components are little, its chemical stability and safety are good, without potassium chlorate. It has advantages of low mechanical sensibility and high safety, good bang rate and sound-level value, etc. It is an ideal safe firecracker powder.

Solid-state proton conduction: An ab initio molecular dynamics investigation of ammonium perchlorate doped with neutral ammonia

Abstract: The charge-transport mechanism in solid ammonium perchlorate crystal exposed to an ammonia-rich environment is studied using ab initio molecular dynamics. Ammonium perchlorate is an ionic crystal composed of NH 4 and ClO 4 - units that possesses an or- thorhombic phase at T 513 K. Exposure to an ammonia- rich atmosphere allows ammonia molecules to be absorbed into the crystal at interstitial sites. It has been proposed that these neutral ammonias can form short-lived N 2 H 7 complexes with the NH 4 ions allowing proton transfer between them, thereby enhancing the conductivity considerably. To date, however, there has been no direct evidence of this proposed mecha- nism. In this paper, ab initio molecular dynamics techniques are employed to explore this mechanism. By comparing computed infrared spectra of the pure and ammonia-doped crys- tals, we observe a significant broadening of the NH stretch peak into a lower frequency re- gion, indicating through an experimentally verifiable observable, the formation of hydrogen bonds between NH 3 and NH 4 units. This suggestion is confirmed by direct observation of N 2 H 7 complexes from the trajectory. Comparison of the diffusion constants of NH 4 in the pure and doped crystals yields a ratio that is comparable to the experimentally measured con- ductivity ratio and clearly shows an enhanced positive charge mobility. Finally, compelling evidence suggesting the possibility of an ammonia umbrella inversion following proton transfer from NH 4 and NH 3 is obtained.

Synthesis and Properties of Shape-controlled CuO Nanocrystals

Abstract: The CuO nanocrystals were prepared by quick-precipitation and hydrolysis method respectively, using Cu(Ac)2 and NaOH as starting materials. The as-prepared CuO nanocrystals were characterized by XRD, TEM, XPS, UV-Visible absorption spectroscopy and BET. The catalysis of CuO nanocrystals of different morphologies on ammonium perchlorate decomposition was investigated by thermal analysis. Results indicated the variation in temperature for NaOH addition played an important role in the shape of the CuO nanocrystals in precipitation method. Well-dispersed spherical CuO nanocrystals with an average size of 6 nm could be obtained when NaOH was added at 100 ℃ and spindle-shaped CuO nanocrystals exceeding 100 nm in diameter were obtained when NaOH was added at room temperature. Needle-shaped CuO nanocrystals could be prepared by the hydrolysis method, and the presence of small amounts of cetyltrimethylammonium bromide (CTAB) could make needle-shaped CuO well dispersed. The catalytic activity of CuO nanocrystals of different morphologies on ammonium perchlorate decomposition was high. The 2% of spherical CuO nanocrystals could make higher decomposition temperature of ammonium perchlorate decreased to 102 ℃. The exothermic quantity of decomposition was from 590 J·g-1 up to 1 420 J·g-1.

Theoretically exploring methylation effects on solvated multi-hydrogen bonding ammonium perchlorate systems

Abstract: Methyl substituents are introduced into solvated ammonium perchlorate (AP) systems to explicate the effects of methylation on localized hydrogen-bonding. Methylation systems are modeled using density functional theory (DFT) B3LYP type with 4-31G(d, p), 6-311+(2d, p) basis set methods, indicating that whichever methyl group is substituted at the proton site in an ammonium ion or solvent, both methyl groups cease to H-bond, as evidence by elongation of the neighboring bond and characteristic red-shifts in the frequency of vibration. The energy barriers to the conversion from reactants to products in solvated AP systems are also discussed herein to help to elucidate the relationship solubility and H-bonding.

Application of Ammunium Dinitramide in Propellants and Explosives

Abstract: The application of ammanium dinitramide (ADN) as a new oxidizer of propellant and explosives is reviewed, it is considered that ADN is a nice candidate that may replace ammonium perchlorate (AP) oxidizer in propellant compositions. The suggestions about optimization technology to reduce cost, improvement of stabilization, prilling technigues and application of ADN are presented.

Ab Initio Computational Chemical Studies of Molecular Processes and Decomposition in Ammonium Perchlorate

Abstract: : Ammonium perchlorate is widely used as an oxidiser in composite propellants for rocket motors. Its decomposition is of interest in stability, sensitivity and combustion studies for rocket motor safety and performance analysis and prediction. This document presents some theoretical studies conducted to yield insights into the mechanisms and kinetics of ammonium perchlorate decomposition.

Ice-forming fuel

Abstract: FIELD: weather control agents. SUBSTANCE: invention relates to ice-forming fuel for actively affecting overcooled clouds and mists and it is designed for uses in charges of midflight engines of antihail rockets. Fuel is essential for preparing unitary charges according to low-pressure jet molding technology and it functions both as generator of active crystallization sites for overcooled cloud drops and generator of energy required for movement of antihail rockets. Fuel is composed of, wt %: synthetic diene rubber 2.93-3.27, inert plasticizer 4.72- 13.22, burning rate catalyzing plasticizer 0-8.0, quinol ether 0.35-0.39, 4,4'-isopropylidenediphenol epoxide resin 0.50-1.00, silver iodide 1.00- 8.00, ammonium iodide 10.00-14.00, and ammonium perchlorate - the balance. Such composition ensures ice- forming activity at overcooled cloud temperature -6.0 C equal to (0.2-2.6).10-12g-1 at cloud blowing velocity 100 m/sec. EFFECT: increased rocket mass factor and thereby its efficiency and fly distance value. 1 tbl

Method for inflating a gas bag and gas bag module for use in this method

Abstract: A method for inflating a gas bag of a safety arrangement in vehicles provides a gas generator which contains a pyrotechnic propellant comprising an organic fuel and ammonium perchlorate as an oxidizing agent. The pyrotechnic propellant, after its activation, releases a gas which has an amount of hydrochloric acid. A coating is arranged on the inner surface of the gas bag, on which the hydrochloric acid is neutralized or absorbed.

Preparation and characterization of composite particles of Al/ammonium perchlorate

Abstract: Al/Ammonium perchlorate (AP) composite particles were prepared by solvent-nonsolvent method TEM,SEM and XRD were used to characterize their structure and ICP was used to measure their component rateTo research the composite process of Al powder and AP on the propellant, thermal analysis of Al/AP composite particles and propellant contained these composite particles were studied by DTA Results indicate that Al show some catalytic performance on the thermal decomposition of AP in the Al/AP composite particles, while for the simple mixture of Al and AP with the same proportion, Al does not have obvious catalytic effect Compared with the thermal decomposition of the propellant adding pure Al, the peak temperature of high temperature decomposition of the propellant adding composite particles decreases and the total heat release increases greatly Al/AP composite particles can improve the thermal decomposition performance of AP and propellant

Effect of Nanometer Metal Powders on the Thermal Decomposition of Ammonium Perchlorate

Abstract: The decomposition of ammonium perchlorate(AP) in the presence of nanometer metal powders has been investigated by DTA. The results show that nanometer Cu, Ni and Al powders clearly decreased the high decomposition temperature of AP by 130.2, 112.9 and 51.8 ℃ respectively, as compared with that of AP without metal powder, showing good catalytic effects on the higher temperature decomposition of AP. Nanometer Cu powder also obviously decrases the low decomposition temperature of AP by 35.1 ℃, whereas the nanometer Ni and Al powders increased it. The catalytic effects of micron metal powders on the high temperature decomposition of AP are less than that of nanometer metal powders, but all the micron metal powders decrease the low decomposition temperature of AP.

Research on the preparation and catalytic function of nano-CuOAP composite particles

Abstract: The nano-CuOAP composite particles were prepared by means of solvent-nonsolvent method. The morphology and compositions were characterized by TEM,XRD and AA.The results show that the composite particles contain copper oxide (CuO) and ammonium perchlorate (NH4ClO4)only , and CuO is coated by AP. The catalytic function of composite particles was tested by using DSC. The results show that the high exothermic peak of nano-CuOAP composite particles drops down to 101℃ i.e. 5.64℃ in advance to the simple admixture of CuO and AP.It is important that the low exothermic peak of AP decomposition disappeares and the high temperature decomposition of AP begins soon after a phase transforming from orthorhombic to cubic, which provides a feasible way to improve the burning rate of propellants.

Effect of heterogeneity of solid propellants on their intrinsic stability of pyrolysis

Abstract: A time -dependent quasi -one-dimensional computation of the pyrolysis of a pair of alternating slabs of solid fuel and solid oxidizer is performed. The geometry is representative of a two - dimensionalized model of the burning surface of a composite propellant. It is recognized that the two components pyrolyze with different surface temperatures and rates of pyrolysis, owing to the difference in their activation energies of pyrolysis, heats of pyrolysis, and other thermo -physical properties. With the combination of ammonium perchlorate as the oxidizer and polybutad iene binder, it is found that the ratio of the pyrolysis rates of the two slabs tends to unity for fuel -rich equivalence ratios, indicating an approach to a steady state pyrolysis of the combination. On the other hand, for fuel -lean equivalence ratios, th e removal of the ignition source leads to an abrupt fall in the regression rate of the binder, indicating that the pyrolysis cannot be self -sustained. As the mixture moves away from a fuel -rich composition, the time re quired to attain stability tends to b e higher. The results are explained based on the stability of pyrolysis of the combination of ingredients , which is influenced by the difference in their activation energies of pyrolysis.

PRE- AND POST-BURNING ANALYSIS OF NANO-ALLUMINIZED PROPELLANTS. COMPARISON OF FOUR RUSSIAN NANO-Al POWDERS

Abstract: Aluminum nano-powders of Russian production were examined and compared with the final goal to evaluate their application in solid rocket propellant formulations. A detailed investigation, concerning a compared characterization of differently sized aluminum powders, by BET (Specific Surface), EM (Electron Microscopy), XRD (X-Ray Diffraction), and XPS (X-ray Photoelectron Spectroscopy), expands the analysis already presented in the first interim report. A detailed investigation concerning a compared characterization of condensed combustion residues of several propellants, based on differently sized aluminum powders, expands the analysis presented in the second interim report. Experimental data concerning the ballistic characterization of several propellants, in terms of steady burning rates and other ballistic effects, expands the analysis already presented in the third interim report. Flame structures and agglomeration phenomena, at and near the burning surface, of several aluminized formulations were analyzed by high-speed, high-resolution, color, digital video recordings. All ballistic studies were performed at SPLab, Milan, Italy using industrial (for comparison) and laboratory composite solid rocket propellants based on ammonium perchlorate as oxidizer and HTPB as binder. The reference formulation was an AP/HTPB/Al composition with respectively 68/17/15 % mass fractions. Results obtained under a wide variety of operating conditions typical of rocket propulsion indicate, for increasing nano-Al mass fraction or decreasing nano-Al size, larger steady burning rates with essentially the same pressure sensitivity. A variety of other effects connected with nano-Al powders appears, depending on the details of the burning formulations. This first year report is focused on uncoated nano-powders of Russian production; the second year report (if continuation is approved) will deal with coated Russian nano-powders and US nanopowders. From a practical viewpoint, the actual properties of the available nominal Al have to be carefully checked before any actual use. With due precautions, nano-Al can be handled with safety in lab scale experiments, but extension to motor scale at this time is still an unknown.